HK1081194B - 6-amino-1h-indazole compounds as phosphodiesterase 4 inhibitors, pharmaceutical compositions comprising the same, and use thereof - Google Patents

Description

6-amino-1H-indazoles as phosphodiesterase 4 inhibitors, pharmaceutical compositions and uses thereof

This application claims priority to U.S. provisional application 60/396,309 filed on 19/7/2002. This application is related to application 10/051,309 filed on 22/1/2001 and provisional application 60/262,651 thereof, application 60/267,196 filed on 8/2/2001 and application 60/306,140 filed on 14/7/2001, the disclosures of which are incorporated herein by reference in their entireties.

Technical Field

The present invention relates generally to the field of phosphodiesterase 4(PDE 4) enzyme inhibition. More particularly, the invention relates to selective PDE4 inhibition by novel compounds, such as aminoindazole and aminobenzofuran analogs, methods for preparing these compounds, compositions containing these compounds, and methods of use thereof.

Background

Cyclic nucleotide specific Phosphodiesterases (PDEs) represent a class of enzymes that catalyze the hydrolysis of various cyclic nucleosides monophosphate, including cAMP and cGMP. These cyclic nucleotides act as second messengers within the cell and as messengers carry impulses from cell surface receptors that have bound various hormones and neurotransmitters. PDEs function to regulate the levels of cyclic nucleotides in cells and maintain cyclic nucleotide homeostasis by degrading these single cyclic nucleotides, resulting in termination of their messenger role.

PDE enzymes can be divided into 11 classes according to their specificity for hydrolysis of cAMP or cGMP, their sensitivity to calcium, calmodulin or cGMP modulation, and their selective inhibition by various compounds. For example, PDE 1 is Ca-dependent²⁺Calponin stimulation. PDE 2 is cGMP-dependent and is found in the heart and adrenal glands. PDE 3 is cGMP-dependent, and inhibition of this enzyme produces positive inotropic activity. PDE4 is cAMP specific and its inhibition leads to airway relaxation, anti-inflammatory and antidepressant activity. PDE5 appears to be important in regulating cGMP content in vascular smooth muscle, and thus PDE5 inhibitors may have cardiovascular activity. Because of their unique biochemical properties, PDEs are likely to undergo a number of different forms of regulation.

PDE4 differs in various kinetic properties, including low mie constants for cAMP and sensitivity to certain drugs. The PDE4 enzyme class consists of four genes that produce 4 isoforms of the PDE4 enzyme known as PDE 4A, PDE 4B, PDE 4C and PDE 4D [ see: wang et al, Expression, Purification, and analysis of human cAMP-Specific phosphorus estiferase (PDE 4) Subtypes A, B, C, and D, biochem. Biophys. Res. Comm., 234, 320-324 (1997). In addition, various splice variants of each PDE4 isoform have been identified.

The PDE4 isoenzymes are located in the cytosol of cells and are not associated with any known membrane structures. The PDE4 isozyme specifically inactivates cAMP by catalyzing its hydrolysis to adenosine 5' -monophosphate (AMP). Modulation of cAMP activity is important in many biological processes, including inflammation and memory. PDE4 isoenzyme inhibitors such as rolipram, pyraclostrobin, CDP-840 and ariflo are potent anti-inflammatory agents and may therefore be used in the treatment of diseases where inflammation is an issue such as asthma or arthritis. Furthermore, rolipram improves cognitive ability in rats and mice in a learning model.

Rolipram piclamilast

In addition to these compounds such as rolipram, xanthine derivatives such as pentoxifylline, denbufylline and theophylline inhibit PDE4 and have recently attracted considerable attention for their cognition enhancing effects. cAMP and cGMP are second messengers that regulate cellular responses to many different hormones and neurotransmitters. Thus, PDE inhibition and the resultant increase in intracellular cAMP or cGMP in critical cells, such as those in the nervous system and other parts of the body, may be therapeutically important.

Rolipram, which was developed in the past as an antidepressant, selectively inhibits the PDE4 enzyme and has become a standard agent for the classification of PDE enzyme subtypes. Early work in The PDE4 field focused on depression and inflammation, and subsequently has been extended to indications including, for example, dementia [ see "The PDE IV Family Of Calcium-phosphorus diesterases Enzymes", john a. lowe, III et al, Drugs ofhe Future 1992, 17 (9): 799 overview 807 ]. Other clinical developments of rolipram and other first generation PDE4 inhibitors have been terminated by the side effects of these compounds. The major side effect in primates is emesis, while the major side effects in rodents are testicular degranulation, weakening of vascular smooth muscle, psychotropic effects, increased gastric acid secretion and gastric erosion.

Disclosure of Invention

The present invention relates to novel compounds, such as aminoindazole and aminobenzofuran analogs, which inhibit PDE4 enzymes, particularly to improve side effect profiles, e.g., are relatively non-emetic (e.g., as compared to the prior art compounds discussed above). Preferably, the compound selectively inhibits the PDE4 enzyme. The compounds of the invention are also readily accessible to cells, particularly cells of the nervous system.

Furthermore, the present invention provides methods for the synthesis of compounds having such activity and selectivity, as well as methods for treating a patient, e.g., a mammal, including a human, in need of PDE inhibition, particularly PDE4 inhibition, for conditions involving elevated intracellular PDE4 levels or reduced cAMP levels, e.g., involving neurological syndromes, particularly conditions associated with memory impairment, most particularly long term memory impairment, wherein such memory impairment is due in part to catabolism of intracellular cAMP levels by PDE4 enzymes, or wherein such memory impairment can be ameliorated by effectively inhibiting PDE4 enzyme activity.

In a preferred aspect, the compounds of the invention ameliorate these disorders by inhibiting PDE4 enzymes at doses that do not induce emesis.

The present invention includes compounds of formulas I and II:

wherein

R¹Is a hydrogen atom, and is,

an alkyl group having 1 to 8 carbon atoms, which is branched or unbranched and is unsubstituted or substituted one or more times by halogen,

cycloalkyl having 3 to 10, preferably 3 to 8, carbon atoms, which is unsubstituted or substituted one or more times by: halogen, hydroxy, oxygen, cyano, alkyl having 1 to 4 carbon atoms, alkoxy having 1 to 4 carbon atoms, or combinations thereof (e.g., cyclopentyl), or

A heterocyclic group which is saturated, partially saturated or unsaturated, having 5 to 10 ring atoms, wherein at least one ring atom is N, O or an S atom, which is unsubstituted or substituted one or more times by: halogen, alkyl, hydroxy, alkoxy, alkoxyalkoxy, nitro, methylenedioxy, ethylenedioxy, trifluoromethyl, amino, aminomethyl, aminoalkyl, aminoalkoxy, dialkylamino, hydroxyalkyl (e.g., hydroxymethyl), hydroxamic acid, tetrazol-5-yl, hydroxyalkoxy, carboxy, alkoxycarbonyl (e.g., t-butoxycarbonyl, ethoxycarbonyl), cyano, acyl, alkylthio, alkylsulfinyl, alkylsulfonyl, phenoxy, or combinations thereof (e.g., tetrahydrofuranyl, pyridinyl, thienyl, pyrazinyl, quinolinyl, isoquinolinyl, pyrimidinyl, imidazolyl, thiazolyl, and the like),

R²is hydrogen, or

An alkyl group having 1 to 4 carbon atoms, which is branched or unbranched and is unsubstituted or substituted one or more times by: halogen, cyano and/or C_1～4Alkoxy (e.g. CH)₃、C₂H₅、CHF₂、CF₃Etc.), and wherein one or more-CH₂CH₂The radicals-may each be replaced by-CH-or-C.ident.C-,

R³is a compound of formula (I) in the formula (H),

alkyl having 1 to 8, preferably 1 to 4, carbon atoms, which is branched or unbranched and which is unsubstituted or substituted one or more times by: halogen, cyano, C_1～4Alkoxy groups or combinations thereof (such as methyl, ethyl, propyl, etc.),

partially unsaturated carbocyclic-alkyl, wherein the carbocyclic moiety has 5 to 14 carbon atoms and the alkyl moiety is branched or unbranched, has 1 to 5 carbon atoms, and is unsubstituted or substituted one or more times in the carbocyclic moiety by: halogen, alkyl, alkoxy, nitro, cyano, oxygen, or combinations thereof, and the alkyl moiety is optionally substituted with halogen, C_1～4Alkoxy, cyano, or combinations thereof (e.g., cyclohexenylmethyl, etc.),

an arylalkyl group having from 7 to 19 carbon atoms wherein the aryl moiety has from 6 to 14 carbon atoms and the alkyl moiety is branched or unbranched having from 1 to 5 carbon atoms, the arylalkyl group being unsubstituted or substituted on the aryl moiety one or more times by: halogen, trifluoromethyl, CF₃O, nitro, amino, alkyl, alkoxy, alkylamino, dialkylamino, and/or substituted in the alkyl moiety with halogen, cyano or methyl (e.g., benzyl, phenethyl, phenylpropyl, methylbenzyl, methoxybenzyl, trifluoromethyl, benzyl, methylenedioxybenzyl, etc.), or

Heteroarylalkyl, wherein the heteroaryl moiety may be partially or fully saturated and has from 5 to 10 ring atoms, at least one of which is N, O or S, the alkyl moiety being branched or unbranched and has from 1 to 5 carbon atoms, the heteroarylalkyl being unsubstituted or substituted on the heteroaryl moiety one or more times by: halogen, alkyl, alkoxy, cyano, trifluoromethyl, CF₃O, nitro, oxygen, amino, alkylamino, dialkylamino or combinations thereof, and/or substituted in the alkyl moiety with halogen, cyano or methyl or combinations thereof (e.g., pyridylmethyl, pyridylpropyl, methylpyridylmethyl, chloropyridylmethyl, dichloropyridylmethyl, thienylmethyl, thiazolylmethyl, quinolinylmethyl, isoquinolinylmethyl, piperidinylmethyl, furylmethyl, imidazolylmethyl, methylimidazolylmethyl, pyrrolylmethyl, etc.);

R⁴is a compound of formula (I) in the formula (H),

has the advantages ofAryl of 6 to 14 carbon atoms, unsubstituted or substituted one or more times by: halogen, alkyl, alkenyl, alkynyl, hydroxy, alkoxy, alkoxyalkoxy, nitro, methylenedioxy, ethylenedioxy, trifluoromethyl, OCF₃Amino, aminoalkyl, aminoalkoxy, dialkylamino, hydroxyalkyl (e.g., hydroxymethyl), hydroxamic acid, tetrazol-5-yl, 2 (-heterocyclic) tetrazol-5-yl (e.g., 2- (2-tetrahydropyranyl) tetrazol-5-yl), hydroxyalkoxy, carboxy, alkoxycarbonyl (e.g., t-butoxycarbonyl, ethoxycarbonyl), cyano, acyl, alkylthio, alkylsulfinyl, alkylsulfonyl, phenoxy, trialkylsiloxy (e.g., t-butyldimethylsilyloxy), R⁵-L-or combinations thereof (e.g. substituted or unsubstituted phenyl, naphthyl and biphenyl, e.g. phenyl, methylphenyl, chlorophenyl, fluorophenyl, vinylphenyl, cyanophenyl, methylenedioxyphenyl, ethylphenyl, dichlorophenyl, carboxyphenyl, ethoxycarbonylphenyl, dimethylphenyl, hydroxymethylphenyl, nitrophenyl, aminophenyl, etc.), or

Heteroaryl having 5 to 10 ring atoms, wherein at least one ring atom is a heteroatom, which is unsubstituted or substituted one or more times by: halogen, alkyl, hydroxy, alkoxy, alkoxyalkoxy, nitro, methylenedioxy, ethylenedioxy, trifluoromethyl, amino, aminomethyl, aminoalkyl, aminoalkoxy, dialkylamino, hydroxyalkyl (e.g. hydroxymethyl), hydroxamic acid, tetrazol-5-yl, hydroxyalkoxy, carboxy, alkoxycarbonyl (e.g. tert-butoxycarbonyl, ethoxycarbonyl), cyano, acyl, alkylthio, alkylsulfinyl, alkylsulfonyl, phenoxy, trialkylsiloxy (e.g. tert-butyldimethylsiloxy), R⁵-L-or combinations thereof (e.g., pyridyl, thienyl, pyrazinyl, quinolinyl, isoquinolinyl, pyrimidinyl, imidazolyl, thiazolyl, and the like);

R⁵is a compound of formula (I) in the formula (H),

alkyl having 1 to 8, preferably 1 to 4, carbon atoms, which is unsubstituted or substituted one or more times by: halogen, C_1～4-alkyl radical、C_1～4Alkoxy, oxygen or combinations thereof (such as methyl, ethyl, propyl, etc.),

alkylamino or dialkylamino groups in which each alkyl moiety independently has 1 to 8, preferably 1 to 4 carbon atoms (e.g., dimethylamino, etc.),

partially unsaturated carbocycle-alkyl, wherein the carbocycle moiety has 5 to 14 carbon atoms and the alkyl moiety has 1 to 5 carbon atoms, which is unsubstituted or substituted, preferably one or more times in the carbocycle moiety, with: halogen, alkyl, alkoxy, nitro, cyano, oxygen or combinations thereof (e.g., cyclohexenylmethyl, etc.),

cycloalkyl having 3 to 10, preferably 3 to 8, carbon atoms, which is unsubstituted or substituted one or more times by: halogen, hydroxy, oxygen, cyano, alkoxy, alkyl having 1 to 4 carbon atoms, or combinations thereof (e.g., cyclopentyl),

cycloalkylalkyl having 4 to 16, preferably 4 to 12, carbon atoms, which is unsubstituted or substituted one or more times in the cycloalkyl part and/or in the alkyl part by: halogen, oxygen, cyano, hydroxy, alkyl, alkoxy, or combinations thereof (e.g., cyclopentylmethyl, cyclopropylmethyl, and the like),

aryl having 6 to 14 carbon atoms, which is unsubstituted or substituted one or more times by: halogen, alkyl, hydroxy, alkoxy, alkoxyalkoxy, nitro, methylenedioxy, ethylenedioxy, trifluoromethyl, amino, aminomethyl, aminoalkyl, aminoalkoxy, dialkylamino, hydroxyalkyl (e.g., hydroxymethyl), hydroxamic acid, tetrazol-5-yl, hydroxyalkoxy, carboxy, alkoxycarbonyl (e.g., t-butoxycarbonyl, ethoxycarbonyl), cyano, acyl, alkylthio, alkylsulfinyl, alkylsulfonyl (e.g., substituted or unsubstituted phenyl and naphthyl, methylphenyl, chlorophenyl, fluorophenyl, vinylphenyl, cyanophenyl, methylenedioxyphenyl, ethylphenyl, dichlorophenyl, carboxyphenyl, ethoxycarbonylphenyl, dimethylphenyl, hydroxymethylphenyl, nitrophenyl, aminophenyl, and the like),

an arylalkyl group having from 7 to 19 carbon atoms wherein the aryl moiety has from 6 to 14 carbon atoms and the alkyl moiety is branched or unbranched having from 1 to 5 carbon atoms, the arylalkyl group being unsubstituted or substituted on the aryl moiety one or more times by: halogen, trifluoromethyl, CF₃O, nitro, amino, alkyl, alkoxy, amino, alkylamino, dialkylamino, and/or substituted in the alkyl moiety with halogen, cyano or methyl (e.g., benzyl, phenethyl, phenylpropyl, methylbenzyl, methoxybenzyl, trifluoromethyl, benzyl, methylenedioxybenzyl, etc.),

a heterocyclic group which is saturated, partially saturated or unsaturated, having 5 to 10 ring atoms, wherein at least one ring atom is N, O or an S atom, which is unsubstituted or substituted one or more times by: halogen, alkyl, hydroxy, alkoxy, alkoxyalkoxy, nitro, methylenedioxy, ethylenedioxy, trifluoromethyl, amino, aminomethyl, aminoalkyl, aminoalkoxy, dialkylamino, hydroxyalkyl (e.g., hydroxymethyl), hydroxamic acid, tetrazol-5-yl, hydroxyalkoxy, carboxy, alkoxycarbonyl (e.g., t-butoxycarbonyl, ethoxycarbonyl), cyano, acyl, alkylthio, alkylsulfinyl, alkylsulfonyl, phenoxy, or combinations thereof (e.g., pyridyl, thienyl, pyrazinyl, quinolyl, isoquinolyl, pyrimidinyl, imidazolyl, thiazolyl, etc.), or

Heterocycle-alkyl, wherein the heterocycle moiety is saturated, partially saturated or unsaturated and has 5 to 10 ring atoms, at least one of which is N, O or an S atom, and the alkyl moiety is branched or unbranched and has 1 to 5 carbon atoms, which heterocycle-alkyl is unsubstituted or substituted one or more times in the heterocycle moiety by: halogen, alkyl, alkoxy, cyano, trifluoromethyl, CF₃O, nitro, oxo, amino, alkylamino, dialkylamino or combinations thereof, and/or substituted in the alkyl moiety with halogen, cyano or methyl or combinations thereof (e.g., pyridylmethyl, pyridylpropyl, methylpyridylmethyl, etc.);

l is a single bond or a divalent aliphatic radical having up to 8 carbon atoms, in which one or more-CH groups₂-each of the groups is optionally replaced by: -O-, -S-, -SO₂-、-SO-、-NR⁶-、-SO₂NH-、-NHSO₂-、-CO-、-NR⁶CO-、-CONR⁶-, -NHCONH-, -OCONH, -NHCOO-, -SCONH-, -SCSNH-or-NHCSNH- (e.g. -O-, -CH)₂-、-CO-、-CO-O-、-O-CO-、-CO-NH-、-NH-CO-、-CH₂CH₂CH₂-NH-CO-、-CH₂-CH₂-O-、-SO₂-NH-CH₂CH₂-O-、-O-CH₂CH₂-O-、-CH₂-NH-CO-、-CO-NH-CH₂-、-SO₂-NH-、-CH₂-NH-SO₂-、-CH₂CH₂CH₂-SO₂-NH-、-CONHSO₂-and the like); r⁶Is a compound of formula (I) in the formula (H),

alkyl having 1 to 8, preferably 1 to 4, carbon atoms, which is branched or unbranched and which is unsubstituted or substituted one or more times by: halogen, C_1～4Alkyl radical, C_1～4Alkoxy, oxygen or combinations thereof (such as methyl, ethyl, propyl, etc.);

R⁷is alkoxy or alkylthio, each having 1 to 4 carbon atoms, which is branched or unbranched and is unsubstituted or substituted one or more times by halogen (e.g. CH)₃、CHF₂、CF₃Etc.),

R⁸is-CO-C_1～4Alkyl, branched or unbranched, and unsubstituted or substituted one or more times by halogen (e.g. CH)₃、CHF₂、CF₃Etc.) or is

R⁹Is hydrogen or an alkyl group having 1 to 4 carbon atoms, which is branched or unbranchedAnd is unsubstituted or substituted one or more times by halogen (e.g. CH)₃、CHF₂、CF₃Etc.),

R¹⁰is an alkyl group having 1 to 6 carbon atoms, which is branched or unbranched and is unsubstituted or substituted one or more times by halogen (e.g. CH)₃、CHF₂、CF₃Etc.),

R¹¹is an alkyl group having 1 to 6 carbon atoms, which is branched or unbranched and is unsubstituted or substituted one or more times by halogen (e.g. CH)₃、CHF₂、CF₃Etc.),

x and Y are each independently O or S, and

a is an alkylene group having 2 to 7 carbon atoms, which is unsubstituted or substituted one or more times by halogen;

wherein R in formula I³And R⁴Are not both H, and R in formula II³And R⁴At least one of which is not H.

According to another aspect of the present invention there is provided a class of novel compounds of formulae III and IV:

wherein R is¹、R²、R³、R⁴、R⁷And R⁸As defined above. The compounds of this subclass of formula I and II not only have PDE4 inhibitory activity, but are also useful as intermediates in the preparation of compounds of formula II, wherein R³And R⁴Are not H.

Further, preferred compounds of formula I and II are compounds of formula V and VI:

wherein R is¹、R²、R⁴、R⁷And R⁸As defined in formulas I and II, and one of B, D and E is N and the remainder are C. Preferably, D is N. And, R⁴Preferably pyridyl or phenyl, each of which may be substituted or unsubstituted.

According to another aspect of the invention, the compounds of formulae I and II are selected from the following compounds:

7-methoxy-2- (2-methyl- (1, 3-dioxolan-2-yl) -4- [ N- (4-pyridylmethyl) ] aminobenzofuran,

7-methoxy-2- (2-methyl- (1, 3-dioxolan-2-yl) -4- [ N- (3-pyridylmethyl) ] aminobenzofuran,

7-methoxy-2- (2-methyl- (1, 3-dioxolan-2-yl) -4- [ N-phenyl-N- (4-pyridylmethyl) ] aminobenzofuran,

7-methoxy-2- (2-methyl- (1, 3-dioxolan-2-yl) -4- [ N- (3-cyanophenyl) -N- (3-pyridylmethyl) ] aminobenzofuran,

7-methoxy-2- (2-methyl- (1, 3-dioxolan-2-yl) -4- [ N-phenyl-N- (3-pyridylmethyl) ] aminobenzofuran,

7-methoxy-2- (2-methyl- (1, 3-dioxolan-2-yl) -4- [ N- (3-cyanophenyl) -N- (4-pyridylmethyl) ] aminobenzofuran,

7-methoxy-2- (2-methyl- (1, 3-dioxolan-2-yl) -4- [ N- (4-acetylphenyl) -N- (3-pyridylmethyl) ] aminobenzofuran,

7-methoxy-2- (2-methyl- (1, 3-dioxolan-2-yl) -4- [ N- (4-carboxyphenyl) -N- (3-pyridylmethyl) ] aminobenzofuran,

7-methoxy-2- (2-methyl- (1, 3-dioxolan-2-yl) -4- [ N- (4- (2H-tetrazol-5-yl) phenyl) -N- (3-pyridylmethyl) ] aminobenzofuran,

7-methoxy-2- (2-methyl- (1, 3-dioxolan-2-yl) -4- [ N- (4-carboxy-3-chlorophenyl) -N- (3-pyridylmethyl) ] aminobenzofuran,

7-methoxy-2- (2-methyl- (1, 3-dioxolan-2-yl) -4- [ N- (3-carboxy-5-fluorophenyl) -N- (3-pyridylmethyl) ] aminobenzofuran,

1-cyclopentyl-6- [ N- (3- (1, 1-dimethylethoxycarbonyl) phenyl) -N- (3-pyridylmethyl) ] -1H-aminoindazole,

2-acetyl-7-methoxy-4- (N- (4-cyanophenyl) -N- (3-pyridylmethyl)) aminobenzofuran,

2-acetyl-7-methoxy-4- (N-phenyl-N- (4-pyridylmethyl)) aminobenzofuran,

1-cyclopentyl-6- (N-phenyl-N- (3-pyridylmethyl)) aminoindazole,

1-cyclopentyl-6- (N- (3-carboxyphenyl) -N- (3-pyridylmethyl)) aminoindazole,

2-acetyl-7-methoxy-4- (N- (3-carboxyphenyl) -N- (3-pyridylmethyl)) aminobenzofuran,

7-methoxy-2- (2-methyl- (1, 3-dioxolan-2-yl) -4- (N- (4-cyanophenyl) -N- (3-pyridylmethyl)) -aminobenzofuran,

2-acetyl-7-methoxy-4- (N- (3-cyanophenyl) -N- (3-pyridylmethyl)) aminobenzofuran,

2-acetyl-7-methoxy-4- (N-phenyl-N- (3-pyridylmethyl)) aminobenzofuran,

2-acetyl-7-methoxy-4- (N- (3-cyanophenyl) -N- (4-pyridylmethyl)) aminobenzofuran,

2-acetyl-7-methoxy-4- (N- (4-acetylphenyl) -N- (3-pyridylmethyl)) aminobenzofuran,

2-acetyl-7-methoxy-4- [ N- (4-carboxyphenyl) -N- (3-pyridylmethyl) ] aminobenzofuran,

2-acetyl-7-methoxy-4- [ N- (4- (2H-tetrazol-5-yl) phenyl) -N- (3-pyridylmethyl) ] aminobenzofuran,

2-acetyl-7-methoxy-4- [ N- (4-carboxy-3-chlorophenyl) -N- (3-pyridylmethyl) ] aminobenzofuran,

2-acetyl-7-methoxy-4- [ N- (3-carboxy-5-fluorophenyl) -N- (3-pyridylmethyl) ] aminobenzofuran,

6-amino-1-cyclopentyl-3-ethyl-6- [ N-3- (1, 1-dimethylethoxycarbonyl) phenyl ] -N- (3-pyridylmethyl) amino-1H-indazole,

1-cyclopentyl-3-ethyl-6- [ N- (3-carboxyphenyl) -N- (3-pyridylmethyl) amino-1H-indazole,

2-acetyl-7-methoxy-N- (4-phenylsulfonylaminocarbonylphenyl) -N- (3-pyridylmethyl) -4-aminobenzofuran,

and

a pharmaceutically acceptable salt thereof,

wherein the optically active compounds may be in the form of their isolated enantiomers or mixtures thereof, including racemic mixtures.

The compounds of the invention are effective in inhibiting or modulating PDE4 activity in an animal, such as a mammal, particularly a human. These compounds exhibit neurological activity, particularly when such activity affects cognition, including long-term memory. These compounds will also be effective in treating diseases involving reduced cAMP levels. This includes, but is not limited to, inflammatory diseases. These compounds may also be useful as antidepressants, or for the treatment of cognitive and adverse symptoms of schizophrenia.

Assays for determining PDE inhibitory activity and selectivity for PDE4 inhibitory activity and selectivity for inhibiting the PDE4 isozyme are known in the art. See, for example, U.S. patent 6,136,821, the disclosure of which is incorporated herein by reference.

According to another aspect of the present invention, there is provided a compound for use as an intermediate in the production of a PDE4 inhibitor as described herein (e.g. a PDE4 inhibitor of formula I and II) and/or for the synthesis of a radiolabeled PDE4 inhibitor analogue as described in the present application.

Accordingly, the present invention provides intermediate compounds corresponding to compounds of formulae I and II, wherein R²、R³、R⁴And R⁸As defined above for formulae I and II, but R¹Or R⁷Is H, tert-butyldimethylsilyl-or a suitable phenol or indazole protecting group. Suitable protecting groups are described, for example, in the following documents: greene, T.W. and Wuts, P.G.M., protective groups in Organic Synthesis, 3^rd Edition，John Wiley&Sons, 1999, pp 246-293. For example by removing the protecting group and allowing the resulting compound of formula (I) wherein R¹Or R⁷Reaction of a compound which is H with a suitable radiolabelling agent, these intermediates may also be used to synthesise a radiolabelled compound, for example where R⁷Is composed of³H₃CO-、²H₃CO-、¹⁴CH₃-or¹¹CH₃-. These radiolabeled compounds are useful for determining tissue distribution of compounds in animals in PET imaging studies and for in vivo, in vitro (ex vivo) and in vitro (in vitro) binding studies.

As described above, wherein R⁴、R⁷And R⁸The compounds of formula III as described hereinbefore are useful in the production of compounds wherein R is³Useful intermediates for compounds of formula II other than H.

And, as before, wherein R³、R⁷And R⁸The compounds of formula IV as described hereinbefore are useful in the production of compounds wherein R is⁴Useful intermediates for compounds of formula II other than H.

Herein, halogen means F, Cl, Br and I. Preferred halogens are F and Cl.

Alkyl, as a group or substituent per se or as part of a group or substituent (e.g. alkylamino, trialkylsiloxy, aminoalkyl, hydroxyalkyl) means a straight-chain or branched aliphatic hydrocarbon radical having from 1 to 12 carbon atoms, preferably from 1 to 8 carbon atoms, in particular from 1 to 4 carbon atoms. Suitable alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl and dodecyl. Other examples of suitable alkyl groups include 1-, 2-or 3-methylbutyl, 1-, 1, 2-or 2, 2-dimethylpropyl, 1-ethylpropyl, 1-, 2-, 3-or 4-methylpentyl, 1-, 1, 2-, 1, 3-, 2-, 2, 3-or 3, 3-dimethylbutyl, 1-or 2-ethylbutyl, ethylmethylpropyl, trimethylpropyl, methylhexyl, dimethylpentyl, ethylpentyl, ethylmethylbutyl, dimethylbutyl, and the like.

Substituted alkyl is alkyl as described above, which is substituted in one or more positions with: halogen, oxygen, hydroxy, C_1～4-alkoxy and/or cyano. Halogen is a preferred substituent, especially F and Cl.

Alkoxy means an alkyl-O-group, and alkoxyalkoxy means an alkyl-O-group, wherein the alkyl moiety is in accordance with the foregoing. Suitable alkoxy and alkoxyalkoxy groups include methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, methoxymethoxy, ethoxymethoxy, propoxymethoxy and methoxyethoxy. Preferred alkoxy groups are methoxy and ethoxy. Similarly, alkoxycarbonyl means alkyl-O-CO-, wherein the alkyl moiety is in accordance with the foregoing. Examples include methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl and tert-butoxycarbonyl.

Cycloalkyl means a monocyclic, bicyclic or tricyclic non-aromatic saturated hydrocarbon group having 3 to 10 carbon atoms, preferably 3 to 8 carbon atoms, particularly 3 to 6 carbon atoms. Suitable cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, norbornyl, 1-decahydronaphthalene, adamantan-1-yl and adamantan-2-yl. Other suitable cycloalkyl groups include spiropentyl, bicyclo [2.1.0] pentyl, bicyclo [3.1.0] hexyl, spiro [2.4] heptyl, spiro [2.5] octyl, bicyclo [5.1.0] octyl, spiro [2.6] nonyl, bicyclo [2.2.0] hexyl, spiro [3.3] heptyl, bicyclo [4.2.0] octyl and spiro [3.5] nonyl. Preferred cycloalkyl groups are cyclopropyl, cyclopentyl and cyclohexyl. Cycloalkyl groups may be substituted, for example by halogen and/or alkyl.

Cycloalkylalkyl refers to cycloalkyl-alkyl groups, wherein the cycloalkyl and alkyl moieties are in accordance with the foregoing. Suitable examples include cyclopropylmethyl and cyclopentylmethyl.

Aryl, as a group or substituent per se or as part of a group or substituent, refers to an aromatic carbocyclic group containing 6 to 14 carbon atoms, preferably 6 to 12 carbon atoms, especially 6 to 10 carbon atoms. Suitable aryl groups include phenyl, naphthyl and biphenyl. Substituted aryl groups include those described above, which are substituted one or more times with: such as halogen, alkyl, hydroxy, alkoxy, nitro, methylenedioxy, ethylenedioxy, amino, alkylamino, dialkylamino, hydroxyalkyl, hydroxyalkoxy, carboxy, cyano, acyl, alkoxycarbonyl, alkylthio, alkylsulfinyl, alkylsulfonyl and phenoxy.

Arylalkyl means aryl-alkyl in which the aryl and alkyl portions are in accordance with the foregoing. Suitable examples include benzyl, 1-phenylethyl, 2-phenylethyl, phenylpropyl, phenylbutyl, phenylpentyl and naphthylmethyl.

The heteroaryl group means an aromatic heterocyclic group having one or two rings and a total number of ring atoms of 5 to 10, wherein at least one ring atom is a heteroatom. Preferably the heteroaryl group contains 1 to 3, especially 1 or 2, heterocyclic atoms selected from N, O and S. Suitable heteroaryl groups include furyl, thienyl, pyrrolyl, pyrazolyl, imidazolyl, triazolyl, tetrazolyl, dithiolyl, oxathialyl, isoxazolyl, oxazolyl, thiazolyl, isothiazolyl, oxadiazolyl, oxatriazolyl, dioxazolyl, oxathiazolyl, thiadiazolyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, triazinyl, oxazinyl, isoxazolyl, oxathiazinyl, oxadiazolyl, benzofuranyl, isobenzofuranyl, thiaindenyl, isothiaindenyl, indolyl, isoindolyl, indazolyl, benzisoxazolyl, benzoxazolyl, benzothiazolyl, benzisothiazolyl, purinyl, benzopyranyl, quinolinyl, isoquinolinyl, cinnolinyl, quinazolinyl, naphthyridinyl or benzoxazinyl, for example 2-thienyl, 3-thienyl, 2-thienyl, 3-or 4-pyridyl, 2-, 3-, 4-, 5-, 6-, 7-or 8-quinolyl and 1-, 3-, 4-, 5-, 6-, 7-or 8-isoquinolyl.

Substituted heteroaryl refers to the above heteroaryl substituted at one or more positions with: such as halogen, aryl, alkyl, alkoxy, carboxyl, methylene, cyano, trifluoromethyl, nitro, oxygen, amino, alkylamino, and dialkylamino.

Heterocycles include heteroaryl as described above and non-aromatic cyclic groups containing at least one heteroatom preferably selected from N, S and O, such as tetrahydrofuranyl, piperidinyl and pyrrolidinyl.

Heterocycle-alkyl refers to a heterocycle-alkyl group wherein the heterocycle and alkyl moieties are in accordance with the foregoing. Suitable examples are pyridylmethyl, thienylmethyl, pyrimidinylmethyl, pyrazinylmethyl and isoquinolinylmethyl.

The partially unsaturated carbocyclic ring structure is a non-aromatic monocyclic or bicyclic ring structure containing 5 to 14 carbon atoms, preferably 6 to 10 carbon atoms, wherein one or more of the ring structures contains at least one C ═ C bond. Suitable examples are cyclopentenyl, cyclohexenyl, cyclohexadienyl, tetrahydronaphthalenyl and indan-2-yl.

Alkenyl means a straight or branched aliphatic group containing 2 to 12 carbon atoms, wherein one or more-CH groups₂-CH₂Each-structure is replaced by-CH ═ CH-. Suitable alkenyl groups are vinyl, 1-propenyl, 2-methylvinyl, 1-butene, 2-butene, 1-pentenyl and 2-pentenyl.

Alkynyl means a straight or branched chain aliphatic radical containing 2 to 12 carbon atoms, wherein one or more-CH groups₂-CH₂-the structures are each replaced by-C ≡ C-. Suitable alkynyl radicals areEthynyl, propynyl, 1-butynyl and 2-butynyl.

Acyl refers to alkanoyl having 1 to 13 carbon atoms wherein the alkyl moiety may be substituted by halogen, alkyl, aryl and/or alkoxy, or aroyl having 7 to 15 carbon atoms wherein the aryl moiety may be substituted by, for example, halogen, alkyl and/or alkoxy. Suitable acyl groups include formyl, acetyl, propionyl, butyryl and benzoyl.

The substituted group preferably has 1 to 3 substituents, particularly 1 to 2 substituents.

In the compounds of formula I, R¹There may be an alkyl group preferably having 2 to 4 carbon atoms, optionally substituted with halogen, preferably fluorine or chlorine.

R¹Cycloalkyl radicals, in particular cyclopentyl or cyclohexyl, may also be preferred.

R²Preferably H or an alkyl group having 1 to 4 carbon atoms, especially ethyl.

R³Preferably hydrogen, alkyl having 1 to 4 carbon atoms (e.g., methyl, ethyl, n-propyl or n-butyl), arylalkyl (e.g., substituted or unsubstituted benzyl, phenethyl and phenylpropyl), or heteroarylalkyl (e.g., substituted or unsubstituted pyridylmethyl, furylmethyl, thienylmethyl, pyrrolylmethyl, pyrimidylmethyl, thiazolylmethyl, isoquinolylmethyl and quinolylmethyl). R³Preferred substituents for the aryl and heteroaryl moieties of (A) are F, Cl, CH₃、C₂H₅、OCH₃And CN. In particular, R³Preferably a pyridylmethyl group.

R⁴Preference is given to aryl or heteroaryl, in particular phenyl, naphthyl, biphenyl, furyl, pyrazinyl, pyrimidinyl, pyridyl, quinolyl and isoquinolyl, each of which is unsubstituted or substituted one or more times. Preferred substituents are OH, F, Cl, CF₃Alkyl (e.g. methyl or ethyl), alkoxy (e.g. methoxy and ethoxy), CNVinyl group, CH₂OH、CONHOH、CONH₂Methylenedioxy, COOH, and combinations thereof. For example, R⁴May be phenyl substituted by halogen, COOH and/or CN.

In addition, when R is⁴For aryl, especially phenyl, preferred substituents include R⁵-L-, such as R⁵-、R⁵-O-、R⁵-CO-、R⁵-NH-CO-、R⁵-SO₂-NH-、R⁵-SO₂-NH-alkylene-O-, NH₂-alkyl-NH-CO-, R⁵alkylene-NH-CO-, alkyl-CO-NH-alkyl-, and also methyl, ethyl, Cl, F, CN, OCH₃、CF₃Amino, nitro, HOCH₂And COOH.

When R is⁴Is as a quilt R⁵-SO₂when-NH-substituted aryl, it is preferably substituted phenyl, and R⁵Preferably methyl, ethyl, propyl or phenyl.

When R is⁴Is as a quilt R⁵-SO₂-NH-alkylene-O-substituted aryl, which is preferably substituted phenyl. In these cases, R⁵Preferably methyl, ethyl, propyl or phenyl, and alkylene is preferably-CH₂-、-CH₂CH₂-or-CH₂CH₂CH₂-。

When R is⁴Is as a quilt R⁵-L-substituted aryl, which is preferably substituted phenyl. In these cases, R is preferred⁵The group includes phenyl, tetrazolyl, oxazinyl, piperazinyl, methylpiperazinyl, pyridyl, methylpyridyl, pyrrolinyl, methylpyrrolinyl, piperidyl or methylpiperidyl, and L is preferably a single bond, -O-, -CO-, -CH₂-、-CH₂CH₂-、-CH₂CH₂CH₂-、-CH₂-O-、-CH₂CH₂-O-、-CH₂CH₂CH₂-O-、-CH₂-NH-CH₂CH₂-O-, -CO-NH-, -NH-CO-or-CONHSO₂-。

R⁷Preferably alkoxy having 1 to 4 carbon atoms, which is branched or unbranched and which is unsubstituted or substituted one or more times by halogen, such as CH₃Or C₂H₅。

R⁸preferably-CO-C_1-4Alkyl radicals, e.g. COCH₃。

R⁹Is preferably-CH₃。

X and Y are preferably both O or S, in particular O.

A is preferably-CH₂CH₂-. Furthermore, preferred PDE4 inhibitors of the invention are compounds of the subformulae Ia to IIe corresponding to formulas I and II but showing the following preferred groups:

Ia R³is arylalkyl or heteroarylalkyl, each of which is substituted or unsubstituted; and is

R⁴Is H or is aryl or heteroaryl, each of which is substituted or unsubstituted.

Ib R¹Is cycloalkyl; and is

R²Is H or C₂H₅。

Ic R¹Is cycloalkyl;

R²is H or C₂H₅；

R³Is arylalkyl or heteroarylalkyl, each of which is substituted or unsubstituted; and is

R⁴Is H or is aryl or heteroaralkyl, each of which is substituted or unsubstituted.

Id R¹Is cyclopentyl;

R²is H or C₂H₅；

R³Is arylalkyl or heteroarylalkyl, each of whichIs substituted or unsubstituted; and is

R⁴Is H or is aryl or heteroaryl, each of which is substituted or unsubstituted.

Ie R¹Is cyclopentyl;

R²is H or C₂H₅；

R³Is substituted or unsubstituted pyridyl; and is

R⁴Is H or is aryl or heteroaryl, each of which is substituted or unsubstituted.

If R¹Is cyclopentyl;

R²is H or C₂H₅；

R³Is substituted or unsubstituted pyridyl; and is

R⁴Is substituted or unsubstituted phenyl.

IIa R³Is arylalkyl or heteroarylalkyl, each of which is substituted or unsubstituted; and is

R⁴Is H or is aryl or heteroaryl, each of which is substituted or unsubstituted.

IIb R⁷Is an alkoxy group having 1 to 4 carbon atoms;

R⁸is COCH₃Or

R⁹is-CH₃；

X and Y are both O or S; and is

A is-CH₂CH₂-。

IIc R³Is arylalkyl or heteroarylalkyl, each of which is substituted or unsubstituted; and is

R⁴Is H or is aryl or heteroaryl, each of which is substituted or unsubstituted;

R⁷is an alkoxy group having 1 to 4 carbon atoms;

R⁸is COCH₃Or

R⁹is-CH₃；

X and Y are both O or S; and is

A is-CH₂CH₂-。

IId R³Is substituted or unsubstituted pyridyl;

R⁴is H or is aryl or heteroaryl, each of which is substituted or unsubstituted;

R⁷is an alkoxy group having 1 to 4 carbon atoms;

R⁸is COCH₃Or

R⁹is-CH₃；

X and Y are both O or S; and is

A is-CH₂CH₂-。

IIe R³Is substituted or unsubstituted pyridineA pyridyl group;

R⁴is H or is substituted or unsubstituted phenyl;

R⁷is an alkoxy group having 1 to 4 carbon atoms;

R⁸is COCH₃Or

R⁹is-CH₃；

X and Y are both O or S; and is

A is-CH₂CH₂-。

Preferred aspects include pharmaceutical compositions comprising a compound of the invention and a pharmaceutically acceptable carrier, and optionally another active agent as described below; a method of inhibiting a PDE4 enzyme, in particular an isozyme, e.g. as determined in vitro or in vivo (in an animal, such as in an animal model, or in a mammal or in a human) by conventional assays or the assays described herein; methods of treating neurological syndromes, such as memory loss, particularly long-term memory loss, cognitive disorders or decline, memory disorders, and the like; methods of treating a disease mediated by PDE4 activity, such as a disease described herein, in a mammal, such as a human.

The compounds of the present invention can be prepared conventionally. All starting materials are known or can be prepared conventionally from known starting materials. Some of the methods that may be used are described below.

The starting material 6-amino-1-cyclopentyl-3-ethylindazole can be synthesized from the corresponding 6-carboxy-1-cyclopentyl-3-ethylindazole by Curtius rearrangement. The starting 6-carboxy-1-cyclopentyl-3-ethylindazole can be prepared by methods conventional in the art (see, e.g., WO 098/09961). Alternatively, the starting 6-amino-1-cyclopentyl-3-ethylindazole can be synthesized by amination of a 6-halo-1-cycloalkyl-3-ethylindazole or reduction of a 6-nitro-1-cycloalkyl-3-ethylindazole. The indazole backbone is prepared by several conventional methods in the art, such as by the reaction of cycloalkylhydrazine and 2, 4-difluorophenyl ethyl ketone.

The starting benzofurans are commercially available or can be synthesized according to literature methods by intramolecular aldol condensation of the β -ketoether of a suitably substituted salicylaldehyde. (see Strategies for organic Drug Synthesis and Design, Daniel Lednicomer, Ed., 1998, John Wiley and Sons, Inc. Chapter 10, pp.286-289). Nitration of 2-acetyl-7-methoxybenzofuran and nitric acid in acetic anhydride provides 2-acetyl-7-methoxy-4-nitrobenzofuran. (in the above scheme, the DPA patent refers to U.S. patent application 10/051,309).

The carbonyl group is protected with a suitable base-stable protecting group such as dioxane or dioxolane to provide the desired starting 4-nitrobenzofuran. See WO 99/40085 and WO 99/37640.

One skilled in the art will recognize that certain compounds of formulas I and II may exist in different geometric isomeric forms. In addition, certain compounds of the present invention have one or more asymmetric carbon atoms and thus can exist in the form of optical isomers and racemic or non-racemic mixtures thereof and diastereoisomers and diastereomeric mixtures thereof. All such compounds, including cis-isomers, trans-isomers, diastereomeric mixtures, racemates, diastereomeric mixtures of enantiomers, and substantially pure and pure enantiomers, are within the scope of the invention. The substantially pure enantiomer contains not more than 5% w/w of the corresponding opposite enantiomer, preferably not more than 2%, most preferably not more than 1%.

Optical isomers can be obtained by resolution of racemic mixtures according to conventional methods, for example by formation of diastereomeric salts using optically active acids or bases, or formation of covalent diastereomers. Examples of suitable acids are tartaric acid, diacetyltartaric acid, dibenzoyltartaric acid, ditoluoyltartaric acid and camphorsulfonic acid. Mixtures of diastereomers may be separated into their individual diastereomers on the basis of their physical and/or chemical differences by methods known to those skilled in the art, for example, by chromatography or fractional crystallization. The optically active base or acid is then released from the separated diastereomeric salt. Different methods for separating optical isomers include the use of chiral chromatography (e.g., chiral HPLC columns) with or without conventional derivatization, and optimally selected to maximize separation of enantiomers. Suitable chiral HPLC columns are manufactured by Diacel, e.g., Chiracel OD and Chiracel OJ among many others, which can be routinely selected. Also useful are derivatized or underivatized enzyme separations. The optically active compounds of the formulae I and II can likewise be obtained by chiral synthesis using optically active starting materials.

In addition, one of ordinary skill in the art will recognize that isomeric forms may be differently enriched, e.g.²H、³H、¹¹C and/or¹⁴The compound is used in a form enriched in C content.

The invention also relates to useful forms of the compounds disclosed herein, such as pharmaceutically acceptable salts and prodrugs of all compounds of the invention. Pharmaceutically acceptable salts include salts obtained by reacting the main compound used as a base with an inorganic or organic acid to form a salt, such as salts of hydrochloric acid, sulfuric acid, phosphoric acid, methanesulfonic acid, camphorsulfonic acid, oxalic acid, maleic acid, succinic acid, and citric acid. Pharmaceutically acceptable salts also include salts such as: wherein the main compound acts as an acid and reacts with a suitable base to form, for example, sodium, potassium, calcium, magnesium, ammonium and choline salts. Those skilled in the art will also recognize that acid addition salts of the claimed compounds may be prepared by reacting the compounds with suitable inorganic or organic acids via any of a number of known methods. Alternatively, alkali and alkaline earth metal salts are prepared by reacting the compounds of the present invention with a suitable base via a variety of known methods.

The following are further examples of acid salts that may be obtained by reaction with inorganic or organic acids: acetate, adipate, alginate, citrate, aspartate, benzoate, benzenesulfonate, bisulfate, butyrate, camphorate, digluconate, cyclopentanepropionate, dodecylsulfate, ethanesulfonate, glucoheptanoate, glycerophosphate, hemisulfate, heptanoate, hexanoate, fumarate, hydrobromide, hydroiodide, 2-hydroxy-ethanesulfonate, lactate, maleate, methanesulfonate, nicotinate, 2-naphthalenesulfonate, oxalate, palmitate, pectinate, persulfate, 3-phenylpropionate, picrate, pivalate, propionate, succinate, tartrate, thiocyanate, tosylate, methanesulfonate, and undecanoate.

Preferably, the salt formed is pharmaceutically acceptable for administration to a mammal. However, pharmaceutically unacceptable salts of the compounds are suitable as intermediates, for example for isolating the compound in salt form and then converting the salt back to the free base compound by treatment with an alkaline reagent. The free base may then be converted into a pharmaceutically acceptable acid addition salt, if desired.

The compounds of the invention may be administered alone or as the active ingredient of the formulation. Thus, the invention also includes pharmaceutical compositions of compounds of formula I or II containing, for example, one or more pharmaceutically acceptable carriers.

There are a number of standard references which describe the preparation of various formulations suitable for administration of the compounds of the present invention. Examples of possible formulations and preparations are included in the following documents, for example: the Handbook of Pharmaceutical Excipients, American Pharmaceutical Association (current edition); pharmaceutical Dosage Forms: tablets (Lieberman, Lachman and Schwartz, editors) current edition, Marcel Dekker, Inc. published, and Remington's Pharmaceutical Sciences (Arthur Osol, editor), 1553-.

Due to the high degree of PDE4 inhibition of the compounds of the invention, they can be administered to anyone in need or desire of PDE4 inhibition and/or improved cognition. Administration can be carried out as needed by the patient, for example, oral, nasal, parenteral (subcutaneous, intravenous, intramuscular, intrasternal, and infusion), inhalation, rectal, vaginal, topical, localized, transdermal, and ocular.

Various solid oral dosage forms may be used for administration of the compounds of the present invention, including the following solid dosage forms: tablets, gelcaps (gelcaps), capsules, caplets, granules, lozenges, and powders. The compounds of the present invention may be administered alone or in combination with various pharmaceutically acceptable carriers, diluents (e.g., sucrose, mannose, lactose, starch) and excipients known in the art, including but not limited to suspending agents, solubilizers, buffers, binders, disintegrants, preservatives, colorants, flavorants, lubricants and the like. Time release capsules, tablets and gels are also advantageous in the administration of the compounds of the present invention.

Various liquid oral dosage forms may also be used for administration of the compounds of the invention, including aqueous and non-aqueous solutions, emulsions, suspensions, syrups and elixirs. These dosage forms may also contain suitable inert diluents known in the art, such as water, and suitable excipients known in the art, such as preservatives, wetting agents, sweeteners, flavoring agents, and agents for emulsifying and/or suspending the compounds of the present invention. For example, the compounds of the present invention may be injected intravenously in the form of an isotonic sterile solution. Other formulations are also possible.

Suppositories for rectal administration of the compounds of the invention can be prepared by mixing the compound with suitable excipients such as cocoa butter, salicylates and polyethylene glycols. Formulations for vaginal administration may be in the form of a pessary, tampon, cream, gel, paste, foam or spray containing the active ingredient and a suitable carrier as known in the art.

For topical administration, the pharmaceutical composition may be in the form of a cream, ointment, liniment, lotion, emulsion, suspension, gel, solution, paste, powder, spray, and drops suitable for administration to the skin, eye, ear, or nose. Topical administration may also include transdermal administration via a device such as a transdermal patch.

Aerosol formulations suitable for administration by inhalation may also be prepared. For example, for the treatment of respiratory diseases, the compounds of the present invention may be administered by inhalation of powders (e.g. micronised) or as nebulized solutions or suspensions. The aerosol formulation may be placed in a propellant that can be pressurized.

The compounds may also be administered as the sole active agent or in combination with other pharmaceutical agents, such as other agents used in the treatment of cognitive disorders and/or in the treatment of psychosis, e.g., other PDE4 inhibitors, calcium channel blockers, cholinergics, adenosine receptor modulators, amphakines NMDA-R modulators, mGluR modulators, and cholinesterase inhibitors (e.g., donepezil, rivastigmine (rivastigmine), and glanthanamine). In these combinations, each active ingredient may be administered in accordance with their conventional dosage ranges or dosages below their conventional dosage ranges.

The invention also includes therapeutic methods involving PDE4 enzyme inhibition. Accordingly, the invention includes a method of selectively inhibiting the PDE4 enzyme in an animal, such as a mammal, particularly a human, wherein such inhibition has a therapeutic effect, e.g., such inhibition may ameliorate a condition involving neurological syndrome, such as memory loss, particularly long-term memory loss. These methods comprise administering to an animal, particularly a mammal, most particularly a human, in need thereof, an inhibitory amount of a compound disclosed herein, alone or as part of a formulation.

Symptoms of memory impairment manifest as a dysfunction in the ability to learn new information and/or an inability to recall previously learned information. Memory disorders are the major symptoms of dementia and may also be syndromes associated with diseases such as alzheimer's disease, schizophrenia, parkinson's disease, huntington's disease, pick's disease, creutzfeldt-jakob disease, HIV, cardiovascular disease and head trauma, as well as age-related cognitive decline.

Dementia is a disease involving memory loss and other intellectual impairment independent of memory. The invention includes methods for treating patients with memory impairment of all forms of dementia. Dementias are classified according to their etiology and include: neurodegenerative dementias (such as alzheimer's disease, parkinson's disease, huntington's disease, pick's disease), vascular (such as infarction, hemorrhage, heart disease), mixed vascular and alzheimer's disease, bacterial meningitis, creutzfeldt-jakob disease, multiple sclerosis, traumatic (such as subdural hematoma or traumatic brain injury), infectious (such as HIV), hereditary (down's syndrome), toxic (such as heavy metals, alcohol, certain drugs), metabolic (such as vitamin B12 or folate deficiency), CNS hypoxia, cushing's syndrome, psychiatric disorders (such as depression and schizophrenia) and hydrocephalus.

The invention includes methods for treating memory loss independent of dementia, including Mild Cognitive Impairment (MCI) and age-related cognitive decline. The invention includes methods for treating memory impairment resulting from disease. In another application, the invention includes methods for treating memory loss resulting from the use of general anesthetics, chemotherapy, radiation therapy, post-operative trauma, and therapeutic intervention.

The compounds of the invention may be used in the treatment of psychiatric disorders including schizophrenia, bipolar or manic depression, major depression, and drug addiction and morphine dependence. These compounds can improve insomnia. PDE4 inhibitors can be used to elevate cAMP levels and prevent neuronal apoptosis. PDE4 inhibitors are also known as anti-inflammatory agents. The combination of anti-apoptotic and anti-inflammatory properties makes these compounds useful for treating neurodegeneration resulting from any disease or injury, including stroke, spinal cord injury, neurogenesis, alzheimer's disease, multiple sclerosis, Amyotrophic Lateral Sclerosis (ALS), and Multiple System Atrophy (MSA).

Thus, according to a preferred embodiment, the invention comprises a method for treating a patient suffering from a memory disorder caused by a disease such as: alzheimer's disease, schizophrenia, parkinson's disease, huntington's disease, pick's disease, creutzfeldt-jakob disease, depression, aging, head trauma, stroke, CNS hypoxia, brain aging, multi-infarct dementia and other neurological disorders including acute neuropathy as well as HIV and cardiovascular disease, comprising administering an effective amount of a compound of formula I or II or a pharmaceutically acceptable salt thereof.

The compounds of the present invention may also be used in a method of treating a patient suffering from a disease characterized by reduced NMDA function, such as schizophrenia. The compounds may also be used in the treatment of psychiatric disorders characterised by elevated PDE4 levels, for example various forms of depression such as manic depression, major depression and depression associated with psychosis and neuropathy.

As noted, the compounds of the present invention also exhibit anti-inflammatory activity. Accordingly, the compounds of the present invention are useful in the treatment of various allergic and inflammatory diseases, particularly disorders characterized by reduced levels of cyclic AMP and/or increased levels of phosphodiesterase 4. Thus, according to another embodiment of the present invention, there is provided a method of treating allergic and inflammatory conditions comprising administering an effective amount of a compound of formula I or II or a pharmaceutically acceptable salt thereof. These conditions include: asthma, chronic bronchitis, Chronic Obstructive Pulmonary Disease (COPD), atopic dermatitis, urticaria, allergic rhinitis, allergic conjunctivitis, vernal conjunctivitis, eosinophilic granuloma, psoriasis, inflammatory arthritis, rheumatoid arthritis, septic shock, ulcerative colitis, Crohn's disease, reperfusion injury of myocardium and brain, chronic glomerulonephritis, endotoxic shock, adult respiratory distress syndrome, cystic fibrosis, arterial restenosis, atherosclerosis, keratosis, rheumatoid spondylitis, osteoarthritis, pyresis, diabetes, pneumoconiosis, chronic obstructive airways disease, chronic obstructive pulmonary disease, toxic and allergic contact eczema, atopic eczema, seborrheic eczema, lichen simplex, sunburn, pruritis of the anogenital area, alopecia areata, hypertrophic scars, discoid lupus erythematosus, systemic lupus erythematosus, chronic inflammatory bowel disease, follicular and large-area pyoderma, endogenous and exogenous acne, rosacea, Behcet's disease, allergic purpuric nephritis, inflammatory bowel disease, leukemia, multiple sclerosis, gastroenteropathy, autoimmune disease, etc.

PDE4 inhibitors for the treatment of asthma, chronic bronchitis, psoriasis, allergic rhinitis and other inflammatory diseases and for the inhibition of tumor necrosis factor are known in the art. See, for example, WO 98/58901, JP-11-18957, JP 10-072415, WO 93/25517, WO 94/14742, US 5,814,651 and US 5,935,9778. These references also describe assays for determining PDE4 inhibitory activity, as well as methods for synthesizing these compounds. These documents are incorporated herein by reference in their entirety.

PDE4 inhibitors may be used for the prevention or amelioration of osteoporosis, as antibiotics, for the treatment of cardiovascular disease by mobilizing cholesterol in atherosclerotic lesions, can be used for treating Rheumatoid Arthritis (RA), inhibiting proliferation of mesenchymal cells after transplantation for a long time, for treating urethral blockage secondary to benign prostatic hyperplasia, for inhibiting chemotaxis and reducing the invasion of colon cancer cells, for the treatment of B-cell chronic lymphocytic leukemia (B-CLL), for inhibiting uterine contractions, for reducing pulmonary vascular Ischemia Reperfusion Injury (IRI), for corneal hydration, for inhibiting IL-2R expression, thereby eliminating HIV-1DNA nuclei from entering memory T cells, for increasing glucose-induced insulin secretion, for the simultaneous prevention and treatment of colitis, and for inhibiting mast cell degranulation.

The compounds of the invention may be administered as the sole active agent or in combination with other pharmaceutical agents such as other agents useful in the treatment of cognitive disorders and/or in the treatment of psychosis, e.g., other PDE4 inhibitors, calcium channel blockers, cholinergics, adenosine receptor modulators, amphakines NMDA-R modulators, mGluR modulators, and cholinesterase inhibitors (e.g., donepezil, rivastigmine, and glanthanamine). In these combinations, each active ingredient may be administered in accordance with their conventional dosage ranges or dosages below their conventional dosage ranges.

The dosage of the compounds of the invention depends on a variety of factors including the particular syndrome being treated, the severity of the symptoms, the route of administration, the frequency of the dosage intervals, the particular compound used, the potency, toxicological profile, pharmacokinetic profile of the compound and the presence of any deleterious side effects, etc.

The compounds of the invention are typically administered to a mammal at conventional dosage levels for PDE4 inhibitors, such as the known compounds described above. For example, the compounds may be administered in one or more doses, for example orally, at a level of 0.01 to 100 mg/kg/day, preferably 0.1 to 70 mg/kg/day, especially 0.5 to 10 mg/kg/day. For example, a unit dosage form may contain 0.1 to 50mg of active compound. For intravenous administration, the compounds may be administered in one or more doses, and the dose level is, for example, 0.001 to 50 mg/kg/day, preferably 0.001 to 10 mg/kg/day, particularly 0.01 to 1 mg/kg/day. For example, a unit dosage form may contain 0.1 to 10mg of active compound.

In practicing the methods of the present invention, it will of course be understood that reference to particular buffers, media, reagents, cells, culture conditions, and the like, is not intended to be limiting, but is intended to include all such related materials which one of ordinary skill in the art would recognize as being useful or valuable in the particular context in question. For example, one buffer system or medium can often be substituted for another while still achieving similar, if not identical, effects. Those skilled in the art are well aware of such systems and methods and are therefore able to make such substitutions without undue experimentation to best serve their purposes in using the methods and steps disclosed herein.

All applications, patents, and publications cited above and below, and U.S. provisional application 60/396,726 filed on 7/19/2002, are hereby incorporated by reference in their entirety.

Examples

The invention will now be further described by the following non-limiting examples. In practicing the disclosure of these examples, it should be clearly understood that they are no doubt indicative of those skilled in the art as to other and different embodiments of the disclosed method.

In the foregoing and following examples, all temperatures are given in degrees Celsius without calibration; and all parts and percentages are by weight unless otherwise indicated.

Example 1

6-amino-1-cyclopentyl-3-ethyl-1H-indazole

To a mixture of 1-cyclopentyl-3-ethyl-1H-indazole-6-carboxylic acid (258mg) and triethylamine (0.56mL) in tert-butanol (1mL) was added diphenylphosphorylazide (0.33 mL). The mixture was stirred at 100 ℃ for 4 h, then partitioned between water (25mL) and diethyl ether (25 mL). The ether layer was collected and dried (MgSO)₄) Through a silica gel plug. The silica gel was washed with an additional 25mL of diethyl ether and the mixture was concentrated in vacuo. The residue was dissolved in THF (5mL), 6N aqueous HCl (1mL) was added, and the mixture was stirred for 18 hours. Ether (25mL) and water (25mL) were added, and the ether layer was collected and dried (MgSO₄) And concentrated in vacuo. The residue was purified by silica gel column chromatography to give 6-amino-1-cyclopentyl-3-ethyl-1H-indazole (59% yield), 0.14 g.¹H NMR(300MHz)δ7.45(d，J＝8.4Hz，1H)，6.52(m，2H)，4.74(p，J＝7.8Hz，1H)，3.86(br，2H)，2.95(q，J＝7.7Hz，2H)，2.3-1.8(m，6H)，1.8-1.6(m，2H)，1.37(t，J＝7.7Hz，3H)。

Example 2

1-cyclopentyl-3-ethyl-6- [ N- (3-pyridylmethyl) ] amino-1H-indazole

To a mixture of 3-pyridinecarboxaldehyde (106mg, 1.0mol) in methanol (5.0mL) was added 6-amino-1-cyclopentyl-3-ethyl-1H-indazole (240mg, 1.05mmol) and p-toluenesulfonic acid monohydrate (2.0 mg). The reaction mixture was stirred for 4 hours. The flask was then cooled to 0 ℃ and sodium borohydride (0.09g, 2.3mmol) was added portionwise over 4 hours. The reaction mixture was allowed to warm to room temperature with stirring over 16 hours. TLC indicated completion of the reaction (1: 3 hex: BA). The solvent was evaporated, diluted with water (10mL) and extracted with ethyl acetate (2X 20 mL). The combined organic layers were washed with brine (5mL), dried over sodium sulfate, and concentrated to give the desired product.¹HNMR(300MHz)δ8.64(s，1H)，8.51(m，1H)，7.70(m，1H)，7.42(d，J＝8.4Hz，1H)，7.25(m，1H)，6.50(m，1H)，6.33(s，1H)，4.68(p，J＝7.8Hz，1H)，4.55(br，1H)，4.40(s，1H)，2.90(q，J＝7.7Hz，2H)，2.1-1.8(m，6H)，1.8-1.6(m，2H)，1.34(t，J＝7.7Hz，3H)。

The following compounds were prepared in a similar manner to example 2 above:

1-cyclopentyl-6- (3-pyridylmethyl) aminoindazole,

7-methoxy-2- (2-methyl- (1, 3-dioxolan-2-yl) -4- [ N- (3-pyridylmethyl) ] aminobenzofuran, with

7-methoxy-2- (2-methyl- (1, 3-dioxolan-2-yl) -4- [ N- (4-pyridylmethyl) ] aminobenzofuran.

Example 3

6-amino-1-cyclopentyl-3-ethyl-6- [ N-3- (1, 1-dimethylethoxycarbonyl) phenyl ] -N- (3-pyridylmethyl) amino-1H-indazole

To a 10mL dry argon-flushed flask were added 0.06g (0.61mmol) NaOtBu, 36mg Pd in the following order₂dba₃2.0mL of toluene, 0.014mL of P (tBu)₃And 2.0mL of a solution of 140mg (0.436mmol) of 6-amino-1-cyclopentyl-3-ethyl-N- (3-pyridylmethyl) -1H-indazole in toluene. 310mg (1.5mmol) of tert-butyl 3-iodobenzoate are added dropwise with stirring and the mixture is stirredThe mixture was stirred for 18 hours. The reaction mixture was diluted with ethyl acetate, washed twice with water and extracted with 3X 15mL of 3N HCl. The combined acid extracts were washed with 15mL EtOAc, followed by careful neutralization with 6N NaOH to a pH greater than 12. The aqueous base solution was extracted with 2X 15mL EtOAc, and the combined organic phases were washed with 15mL water and brine, dried (MgSO 4)₄) And concentrated. The residue was purified by silica gel chromatography (Biotage Flash 40M) eluting with 25% ethyl acetate in hexane.¹H NMR(300MHz)δ8.65(br，1H)，8.51(br，1H)，8.26(d，J＝8.4，1H)，7.75(m，1H)，7.7-7.5(m，3H)，7.27(m，1H)，7.1-7.0(m，2H)，6.85(d，J＝8.4，1H)，5.22(s，1H)，4.76(p，J＝7.8Hz，1H)，2.96(q，J＝7.7Hz，2H)，2.1-2.8(m，6H)，1.8-1.6(m，2H)，1.54(s，9H)，1.34(t，J＝7.7Hz，3H)。

The following compounds were prepared in a similar manner to example 3 above:

7-methoxy-2- (2-methyl- (1, 3-dioxolan-2-yl)) -4- [ N-phenyl-N- (4-pyridylmethyl) ] aminobenzofuran,

7-methoxy-2- (2-methyl- (1, 3-dioxolan-2-yl)) -4- [ N- (4-cyanophenyl) -N- (3-pyridylmethyl) ] aminobenzofuran,

7-methoxy-2- (2-methyl- (1, 3-dioxolan-2-yl)) -4- [ N- (3-cyanophenyl) -N- (3-pyridylmethyl) ] aminobenzofuran,

7-methoxy-2- (2-methyl- (1, 3-dioxolan-2-yl)) -4- [ N-phenyl-N- (3-pyridylmethyl) ] aminobenzofuran,

7-methoxy-2- (2-methyl- (1, 3-dioxolan-2-yl)) -4- [ N- (3-cyanophenyl) -N- (4-pyridylmethyl) ] aminobenzofuran,

7-methoxy-2- (2-methyl- (1, 3-dioxolan-2-yl)) -4- [ N- (4-acetylphenyl) -N- (3-pyridylmethyl) ] aminobenzofuran,

7-methoxy-2- (2-methyl- (1, 3-dioxolan-2-yl)) -4- [ N- (4-carboxyphenyl) -N- (3-pyridylmethyl) ] aminobenzofuran,

7-methoxy-2- (2-methyl- (1, 3-dioxolan-2-yl)) -4- [ N- (4- (2H-tetrazol-5-yl) phenyl) -N- (3-pyridylmethyl) ] aminobenzofuran,

7-methoxy-2- (2-methyl- (1, 3-dioxolan-2-yl)) -4- [ N- (4-carboxy-3-chlorophenyl) -N- (3-pyridylmethyl) ] aminobenzofuran,

7-methoxy-2- (2-methyl- (1, 3-dioxolan-2-yl)) -4- [ N- (3-carboxy-5-fluorophenyl) -N- (3-pyridylmethyl) ] aminobenzofuran,

1-cyclopentyl-6- [ N-phenyl-N- (3-pyridylmethyl) ] aminobenzofuran, with

1-cyclopentyl-6- [ N- (3- (1, 1-dimethylethoxycarbonyl) phenyl) -N- (3-pyridylmethyl) ] -1H-aminoindazole.

Example 4

6-amino-1-cyclopentyl-3-ethyl-6- [ N- (3-carboxyphenyl) -N- (3-pyridylmethyl) ] amino-1H-indazole

170mg (0.344mmol) of 6-amino-1-cyclopentyl-3-ethyl-N- [3- (1, 1-dimethylethoxycarbonyl) phenyl]A solution of (E) -N- (3-pyridylmethyl) amino-1H-indazole, 3.35mL of dichloromethane, and 0.84mL of trifluoroacetic acid was stirred at room temperature for 5 hours. The solution was washed with 5.0mL of water. Then 5.0mL of water was added and the pH was adjusted to 6 by addition of 10% aqueous sodium hydroxide solution. The combined aqueous layers were extracted with 2X 5mL of dichloromethane. The combined dichloromethane extracts were evaporated through SiO₂The residue was purified by flash chromatography using 10% methanol in dichloromethane as eluent.¹H NMR(300MHz)δ8.90(br，1H)，8.70(br，1H)，8.25(d，J＝8.4，1H)，7.7-7.5(m，4H)，7.20(m，1H)，7.1-7.0(m，2H)，6.86(d，J＝8.4，1H)，5.20(s，1H)，4.76(p，J＝7.8Hz，1H)，2.96(q，J＝7.7Hz，2H)，2.05(m，4H)，1.88(m，2H)，1.65(m，2H)，1.36(t，J＝7.7Hz，3H)。

The following compounds were prepared in a similar manner to example 4 above:

1-cyclopentyl-6- [ N- (3-carboxyphenyl) -N- (3-pyridylmethyl) ] aminoindazole.

Example 5

2-acetyl-7-methoxy-4-nitrobenzofuran

To a solution of 2-acetyl-7-methoxybenzofuran (4.0g) in acetic anhydride (50mL) was added dropwise 70% nitric acid (1.5mL) at 0 ℃. The mixture was allowed to warm to room temperature, stirred for 3 hours, and then poured into ice-cold saturated sodium carbonate (200 mL). Solid sodium carbonate was carefully added with stirring until basic (pH 8). The mixture was filtered and the solid was collected by vacuum filtration. The solid was refluxed in 100mL of methanol for 1 hour, then cooled to 0 ℃ and filtered to give 2-acetyl-7-methoxy-4-nitrobenzofuran (2.1 g).¹H NMR(300MHz)δ8.29(d，J＝8.9Hz，1H)，8.14(s，1H)，7.00(d，J＝8.9Hz，1H)，4.14(s，3H)，2.68(s，3H)。

Example 6

7-methoxy-2- (2-methyl- (1, 3-dioxolan-2-yl)) -4-nitrobenzofuran

A mixture of 2-acetyl-7-methoxy-4-nitrobenzofuran (2.1g), ethylene glycol (2mL), and p-toluenesulfonic acid (25mg) in toluene (50mL) was heated to reflux with an additional Dean-Stark apparatus for 18 hours. The mixture was partitioned between saturated aqueous sodium bicarbonate (50mL) and diethyl ether (50 mL). The ether layer was collected, washed with water (25mL) and brine (25mL), dried (MgSO)₄) And concentrated to give 7-methoxy-2- (2-methyl- (1, 3-dioxolan-2-yl)) -4-nitrobenzofuran (2.1 g).¹H NMR(300MHz)δ8.22(d，J＝9.0Hz，1H)，7.44(s，1H)，6.84(d，J＝9.0Hz，1H)，4.11(s，3H)，4.11(m，4H)，1.86(s，3H)。

Example 7

4-amino-7-methoxy-2- (2-methyl- (1, 3-dioxolan-2-yl)) -benzofuran

To a suspension of 10% Pd (200mg) on activated carbon in ethanol (100mL) under nitrogen was added 7-methoxy-2- (2-methyl- (1, 3-dioxolan-2-yl)) -4-nitrobenzofuran (6.50g, 23 mmol). The reaction mixture was degassed three times under vacuum. The reaction mixture was stirred vigorously while hydrogen was allowed to flow over the reaction mixture. After 4 hours, TLC (5: 1 hex: EA) indicated completion of the reaction. The reaction mixture was filtered through a pad of celite, and the celite was rinsed with additional ethanol. The solvent was removed in vacuo to give 5.1g (88% yield) of the title compound as a yellow oil.

Example 8

2-acetyl-7-methoxy-4- (N- (3-carboxyphenyl) -N- (3-pyridylmethyl) aminobenzofuran

7-methoxy-2- (2-methyl-1, 3-dioxolan-2-yl) -4- (N-3-carboxyphenyl) -N- (3-pyridylmethyl) aminobenzofuran, tert-butyl ester (120mg) was placed in dichloromethane (10mL), trifluoroacetic acid (2mL) was added, and the mixture was stirred for 4 hours. The mixture was concentrated in vacuo and the residue purified by column chromatography eluting with a linear gradient of 0% to 10% methanol in ethyl acetate over 15 minutes to give 65mg of 2-acetyl-7-methoxy-4- (N- (3-carboxyphenyl) -N- (3-pyridylmethyl) aminobenzofuran.¹H NMR(300MHz)δ11.60(br，1H)，8.71(br，1H)，8.56(br，1H)，7.80(d，J＝7.5Hz，1H)，7.60-7.50(m，2H)，7.35(m，1H)，7.20(t，J＝7.9Hz，1H)，7.10-7.00(m，2H)，6.95-6.80(m，2H)，5.09(s，2H)，4.01(s，3H)，2.54(s，3H)。

The following compounds were prepared in a similar manner to example 8 above:

2-acetyl-7-methoxy-4- [ N-phenyl-N- (4-pyridylmethyl) ] aminobenzofuran,

2-acetyl-7-methoxy-4- [ N- (4-cyanophenyl) -N- (3-pyridylmethyl) ] aminobenzofuran,

2-acetyl-7-methoxy-4- [ N- (3-cyanophenyl) -N- (3-pyridylmethyl) ] aminobenzofuran,

2-acetyl-7-methoxy-4- [ N-phenyl-N- (3-pyridylmethyl) ] aminobenzofuran,

2-acetyl-7-methoxy-4- [ N- (3-cyanophenyl) -N- (4-pyridylmethyl) ] aminobenzofuran,

2-acetyl-7-methoxy-4- [ N- (4-acetylphenyl) -N- (3-pyridylmethyl) ] aminobenzofuran,

2-acetyl-7-methoxy-4- [ N- (4-carboxyphenyl) -N- (3-pyridylmethyl) ] aminobenzofuran,

2-acetyl-7-methoxy-4- [ N- (4- (2H-tetrazol-5-yl) phenyl) -N- (3-pyridylmethyl) ] aminobenzofuran,

2-acetyl-7-methoxy-4- [ N- (4-carboxy-3-chlorophenyl) -N- (3-pyridylmethyl) ] aminobenzofuran, with

2-acetyl-7-methoxy-4- [ N- (3-carboxy-5-fluorophenyl) -N- (3-pyridylmethyl) ] aminobenzofuran.

Example 9

2-acetyl-7-methoxy-N- (4-phenylsulfonylaminocarbonylphenyl) -N- (3-pyridylmethyl) -4-aminobenzofuran

EDCI (230mg, 1.2mmol) was added in one portion to a solution of 2-acetyl-7-methoxy-N- (4-carboxyphenyl) -N- (3-pyridylmethyl) -4-aminobenzofuran (416mg, 1.0mmol), benzenesulfonamide (200mg, 1.2mmol) and DMAP (150mg, 1.2mmol) in dichloromethane (5mL) at room temperature and the mixture was stirred at room temperature for 16 h. The mixture was partitioned between water (25mL) and ethyl acetate (25mL) and the pH adjusted to 5-6 with 1.0N HCl. Ethyl acetate was separated, washed with brine (25mL), dried (MgSO)₄) And concentrated in vacuo. The residue was purified by column chromatography eluting with a linear gradient of 5% to 10% methanol in ethyl acetate to give 2-acetyl-7-methoxy-N- (4-phenylsulphonylaminocarbonylphenyl) -N- (3-pyridylmethyl) -4-aminobenzofuran (415 mg).¹H NMR(300MHz)δ8.53(br，1H)，8.46(br，1H)，8.06(d，J＝7.3Hz，2H)，7.8-7.3(m，6H)，7.21(m，1H)，7.1-7.0(m，2H)，6.91(d，J＝8.5Hz，1H)，6.56(d，J＝7.3Hz，2H)，4.99(s，2H)，4.02(s，3H)，2.54(s，3H)。

Example 10

In vitro assay for phosphodiesterase type 4 inhibitory activity

Human PDE4 was obtained from baculovirus-infected Sf9 cells expressing the recombinase. The cDNA encoding hPDE-4D6 was subcloned into a baculovirus vector. Insect cells (Sf9) were infected with this baculovirus and cells were cultured until the protein was expressed. Baculovirus-infected cells were lysed and the lysate was used as a source of hPDE-4D6 enzyme. The enzyme was partially purified by DEAE ion exchange chromatography. This process can be repeated using other PDE-4 enzymes encoded by the cDNA.

The determination method comprises the following steps:

phosphodiesterase type 4 converts cyclic adenosine monophosphate (cAMP) to 5 '-adenosine monophosphate (5' -AMP). Nucleotidase converts 5' -AMP to adenosine. Thus, the combined activity of PDE4 and nucleotidase converts cAMP to adenosine. cAMP and adenosine were easily separated by a neutral alumina column. Phosphodiesterase inhibitors block the conversion of cAMP to adenosine in this assay, and PDE4 inhibitors therefore cause adenosine depletion.

The cell lysate (40. mu.l) expressing hPDE-4D6 was combined with 50. mu.l of the assay mixture and 10. mu.l of inhibitor and incubated for 12 minutes at room temperature. The final concentrations of the assay components were: 0.4. mu.g of enzyme, 10mM Tris-HCl (pH 7.5), 10mM MgCl₂3 μ M cAMP, 0.002U 5' -nucleotidase and 3X 10⁴cpm[3H]cAMP. The reaction was stopped by adding 100. mu.l of boiled 5 mNHCl. An aliquot of 75. mu.l of the reaction mixture was transferred from each well onto an alumina column (Multiplate; Millipore). Elution of labelled adenosine into OptiPlate by spinning at 2000rpm for 2 minutes; add 150. mu.l/well of scintillation fluid to the OptiPlate. The plate was closed, shaken for about 30 minutes, and measured using Wallac Triflux ® [ ]³H]Cpm of adenosine.

Will be describedSome test compounds were dissolved in 100% DMSO and diluted into assay samples to give a final DMSO concentration of 0.1%. DMSO at this concentration did not affect enzyme activity. A decrease in adenosine concentration represents an inhibition of PDE activity. pIC was determined by screening 6-12 compound concentrations ranging from 0.1nM to 10000nM₅₀Values, then plotting drug concentration pairs³Graph of H-adenosine concentration. Estimation of pIC Using non-Linear regression software (Assay Explorer ®)₅₀The value is obtained.

Example 11 (method A)

Passive avoidance in rats, in vivo testing for learning and memory

The tests were performed as described previously (Zhang, h. -t., Crissman, a.m., Dorairaj, n.r., Chandler, l.j. and O' Donnell, j.m., Neuropsychopharmacology, 2000, 23, 198-. The instrument (Model E10-16SC, Coulbour Instruments, Allentown, Pa.) consisted of a double compartment, where the illuminated compartment was connected to the darkened compartment by a shutter. The ground of the darkened compartment consisted of stainless steel rods through which a foot shock could be delivered from a constant current source. All experimental groups were first fitted to the instrument the day before the start of the experiment. During training, rats (male Spraque-Dawley (Harlan), weighing 250-350 g) were placed in the illuminated compartment facing the closed gate 1 minute before lifting the gate. The waiting time to enter the darkened compartment is recorded. After the rats entered the dark compartment, the doors were closed and a 0.5mA shock was applied for 3 seconds. After 24 hours, rats were given 0.1mg/kg MK-801 or saline 30 minutes before injection of saline or test compound (dose 0.1-2.5 mg/kg, i.p.), which was 30 minutes before the start of the retention test. The rat was again placed in the illuminated compartment with the gate open. The waiting time to enter the darkened compartment was recorded for up to 180 seconds, at which point the test was terminated.

All data were analyzed by analysis of variance (ANOVA), and individual comparisons were performed using the Kewman-Keuls test. On average, nude mice took less than 30 seconds to cross the illuminated compartment into the dark compartment. However, most of the vehicle-pretreated rats no longer entered the dark compartment after 24 hours of shock exposure; the average wait time was increased to 175 seconds (p < 0.001). Pretreatment with MK-801(0.1mg/kg) significantly reduced this waiting time compared to vehicle (p < 0.001). The actual test compound reversed this amnesic effect of MK-801 in a dose-dependent fashion in a statistically significant manner.

Example 11 (method B)

Radial arm maze task in rats, in vivo testing for learning and memory

The tests were performed as described previously (Zhang, h. -t., Crissman, a.m., Dorairaj, n.r., Chandler, l.j. and O' Donnell, j.m., Neuropsychopharmacology, 2000, 23, l 98-204). After 5 days of initial cage rearing, rats (male Spraque-Dawley (Harlan) weighing 250-350 g) were placed in an eight-arm radial maze (60X 10X 12cm per arm height; the maze was raised 70cm above the ground) to acclimate for two days. The rats were then placed individually in the center of the maze for 5 minutes and the bolus was placed near the food well, followed by the well at the end of the arm on the next day; the operation was performed twice daily. Then, four randomly selected arms were each baited with a bolus of food. The rat was confined to a central platform (26 cm diameter) for 15 seconds and then allowed to move freely through the maze until it collected all the bolus of food or over 10 minutes, whichever occurred first and whichever was used. Four parameters were recorded: 1) working memory errors, i.e. entry into the bait arm that has been visited during the same trial; 2) referencing a memory error, i.e., entering an arm not baited; 3) a master arm inlet; and 4) test duration (seconds), the time it takes to collect all the food mass in the maze. If the working memory errors were all zero in 5 consecutive trials, and the mean reference memory error was less than 1, the rats began drug testing. MK-801 or saline was injected 15 minutes later with vehicle or test drug, and testing was initiated 45 minutes later. Experiments were performed in a lighted room containing several additional visual cues from the maze.

All data were analyzed by analysis of variance (ANOVA) and individual comparisons were performed using the Kewman-Keuls test. MK-801(0.1mg/kg, i.p.) increased the frequency of working and reference memory errors (p < 0.01) compared to controls. Administration of the actual test compound reverses this amnesic effect of MK-801 on working memory in a dose-dependent fashion in a statistically significant manner.

The preceding examples can be repeated with similar success by substituting the generically or specifically described reactants and/or operating conditions of this invention for those used in the preceding examples.

While particular compounds and processes of the present invention have been illustrated, it will be apparent that changes and modifications can be made without departing from the spirit or scope of the invention.

Claims (29)

1. A compound of formula I:

wherein

R¹A cycloalkyl group having 3 to 10 carbon atoms,

R²is an alkyl group having 1 to 4 carbon atoms, which is branched or unbranched,

R³is a pyridylalkyl group in which the alkyl moiety is branched or unbranched having 1 to 5 carbon atoms,

R⁴is phenyl substituted by carboxyl or alkoxycarbonyl, wherein the alkyl moiety is branched or unbranched and has 1-5 carbon atoms;

wherein the optically active compound may be in the form of one of its isolated enantiomers or a mixture thereof, including a racemic mixture.

2. The compound according to claim 1, which is a compound of formula V:

wherein

R¹A cycloalkyl group having 3 to 10 carbon atoms,

R²is an alkyl group having 1 to 4 carbon atoms, which is branched or unbranched,

R⁴is phenyl substituted by carboxyl or alkoxycarbonyl, wherein the alkyl moiety is branched or unbranched and has 1-5 carbon atoms;

and one of B, D and E is N and the other two are C;

wherein the optically active compound may be in the form of one of its isolated enantiomers or a mixture thereof, including a racemic mixture.

3. A compound according to claim 2, wherein D is N and B and E are C.

4. A compound according to any one of claims 1 to 3, wherein R¹Is cyclopentyl.

5. A compound according to any one of claims 1 to 3, wherein R²Is ethyl.

6. A compound according to claim 1, wherein R³Is a picolyl group.

7. A compound according to any one of claims 1 to 3, wherein R⁴Is phenyl substituted by carboxyl.

8. A compound according to any one of claims 1 to 3, wherein R⁴Is phenyl substituted by ethoxycarbonyl.

9. A compound according to claim 1, which is

6-amino-1-cyclopentyl-3-ethyl-6- [ N-3- (1, 1-dimethylethoxycarbonyl) phenyl ] -N- (3-pyridylmethyl) amino-1H-indazole,

1-cyclopentyl-3-ethyl-6- [ N- (3-carboxyphenyl) -N- (3-pyridylmethyl) amino-1H-indazole, or

A pharmaceutically acceptable salt thereof,

wherein the optically active compounds may be in the form of their isolated enantiomers or mixtures thereof, including racemic mixtures.

10. A pharmaceutical composition comprising a compound according to any one of claims 1 to 9 and a pharmaceutically acceptable carrier.

11. A composition according to claim 10, wherein the compound of claim 1 is provided in a unit dose of 0.1 to 50 mg.

12. Use of a compound according to one of claims 1 to 9 for the manufacture of a medicament for effecting PDE4 enzyme inhibition, improving cognition and/or treating psychosis in a patient.

13. Use according to claim 12, wherein the patient is a human.

14. Use according to claim 12, wherein the patient suffers from cognitive impairment or decline.

15. The use according to claim 12, wherein the patient suffers from memory impairment.

16. The use according to claim 15, wherein the patient suffers from memory impairment caused by alzheimer's disease, schizophrenia, parkinson's disease, huntington's disease, pick's disease, creutzfeld-jakob disease, HIV, cardiovascular disease, head trauma or age-related cognitive decline.

17. The use according to claim 15, wherein the patient suffers from memory impairment due to dementia.

18. Use according to claim 12, wherein the patient is suffering from a psychiatric disorder.

19. The use according to claim 18, wherein the patient is suffering from schizophrenia, bipolar or manic depression, or major depression.

20. Use of a compound according to one of claims 1 to 9 for the preparation of a medicament for the treatment of a patient suffering from a disease associated with a reduced cAMP level.

21. Use according to claim 12, wherein the patient is treated to achieve PDE4 enzyme inhibition.

22. Use of a compound according to one of claims 1 to 9 for the preparation of a medicament for the treatment of patients suffering from allergic or inflammatory diseases.

23. Use of a compound according to one of claims 1 to 9 for the preparation of a medicament for the treatment of patients suffering from neurodegeneration caused by a disease or injury.

24. The use of claim 23, wherein the disease or injury is stroke, spinal cord injury, alzheimer's disease, multiple sclerosis, Amyotrophic Lateral Sclerosis (ALS), or Multiple Systemic Atrophy (MSA).

25. Use according to claim 15, wherein the patient suffers from a memory disorder caused by alzheimer's disease, schizophrenia, parkinson's disease, huntington's disease, pick's disease, creutzfeld-jakob disease, depression, aging, head trauma, stroke, CNS hypoxia, brain senescence, multi-infarct dementia, acute neuronal disease, HIV or cardiovascular disease.

26. The use according to claims 12-25, wherein the compound is administered with one or more pharmaceutical agents for the treatment of cognitive disorders and/or the treatment of psychosis.

27. The use of claim 26, wherein the one or more pharmaceutical agents are selected from PDE4 inhibitors, calcium channel blockers, cholinergics, adenosine receptor modulators, ampakines NMDA-R modulators, mGluR modulators, and cholinesterase inhibitors.

28. Use of a compound according to one of claims 1 to 9 for the preparation of a medicament for the treatment of patients suffering from drug addiction and morphine dependence.

29. Use according to claim 22, wherein the patient suffers from inflammation caused by: asthma, chronic bronchitis, chronic obstructive pulmonary disease, atopic dermatitis, urticaria, allergic rhinitis, allergic conjunctivitis, vernal conjunctivitis, eosinophilic granuloma, psoriasis, inflammatory arthritis, rheumatoid arthritis, septic shock, ulcerative colitis, crohn's disease, reperfusion injury of the myocardium and brain, chronic glomerulonephritis, endotoxic shock, adult respiratory distress syndrome, cystic fibrosis, arterial restenosis, atherosclerosis, keratosis, rheumatoid spondylitis, osteoarthritis, pyresis, diabetes, pneumoconiosis, chronic obstructive airways disease, chronic obstructive pulmonary disease, toxic and allergic contact eczema, atopic eczema, seborrheic eczema, lichen simplex, sunburn, pruritus ani-genital area, alopecia areata, hypertrophic scars, discoid lupus erythematosus, systemic lupus erythematosus, follicular and large area pyoderma, Endogenous and exogenous acne, rosacea, behcet's disease, allergic purpuric nephritis, inflammatory bowel disease, leukemia, multiple sclerosis, gastrointestinal disorders, or autoimmune diseases.