CH669195A5 - FURANE-3-carboxylic acid derivatives and their use as SUNSCREEN AGENTS OUTSIDE THE TEXTILE INDUSTRY. - Google Patents

Description

669 195

PATENT CLAIMS 1. Furanecarboxylic acid derivatives of the general formula I

R3 \ ^ CO - ^ - R1 »

XX,

alkyl-substituted furan-3-carboxylic acids are significantly superior in their stabilizing effect to the corresponding furan-2-carboxylic acid derivatives.

The invention now relates to furan carboxylic acid derivative of the general formula I.

R2

in the

R 'to R3 independently of one another hydrogen, alkyl, cyclohexyl or phenyl, but not more than two of these radicals simultaneously hydrogen and R4 a radical of the formula

10th

R3 ^, ^ CO

XX

R2

R 1

-R ^

-N

, R5 "R6

R6 R6

I 1 D 3 -N-A-N-0 C \ ^ R J

in the

R1 to R3 independently of one another are hydrogen, alkyl, 15 cyclohexyl or phenyl, but not more than two of these radicals simultaneously hydrogen and R4 is a radical of the formula

R

R2

20th

-N

are, where

A is a bridge member which contains a heterocyclic ring or up to 3 times Cr to CI2-alkylene interrupted by ether oxygen or up to 3 times nitrogen-interrupted C | - to C12-alkylene and

R5 CT to C: rAralkyl or C4 to C12 cycloalkylalkyl or a Cr to CI2 alkyl containing a heterocycle and R6 a radical of the formula

-RS -r6

R6 R6

I I

-N-A-N-0 C \. ^ -R3

-XX

R1-

R2

25th

30th

R7

~ 4-R 0

N-R '1 R 1 0

are, where

A is a bridge member which contains a heterocyclic ring or up to 3 times ether-interrupted Cj to C | 2-alkylene or up to 3 times nitrogen-interrupted Cr to C | 2-alkylene and

R5 is C7 to CI2 aralkyl or C4 to C12 cycloalkylalkyl or a Cr to C 1-4 alkyl containing a heterocycle and R6 is a radical of the formula

R3

are in the

R7 to R10 Cr to C4-alkyl,

R7 to R8 or R9 and R '° together a tetra or pentamethylene bridge and

R11 is hydrogen, C2 to CI6 acyl, Cr to C8 alkyl, C3 to C8 alkenyl. C2- to C4-hydroxyalkyl or aralkyl and their salts.

2. Use of the compounds according to claim 1 as light stabilizers outside the textile industry.

DESCRIPTION It is already known that 2,2,6,6-tetraalkylpiperidine derivatives are excellent light stabilizers for organic polymers. Furancarboxylic acid derivatives have also become known among them.

DE-OS 22 58 752 describes tetraalkylpiperidinyl esters of furan-2-carboxylic acid and furan-2,5-dicarboxylic acid. The publication WO 81 02 021 mentions the tri- (2,2,6,6-tetramethyl-4-piperidinyl) ester of a furan tricarboxylic acid which is not precisely defined. The published patent application DE-OS 26 23 422 finally describes tetraalkylpiperidinyl esters of furan-2-carboxylic acid.

DE-PS 20 40 975 claims tetraalkylpiperidinyl amides of furan-2-carboxylic acid and furan-2,3,4-tricarboxylic acid, while DE-PS 23 49 962 describes pentaalkylpiperidi-nylamides of furan-2-carboxylic acid.

A common feature of the previously described furan-carboxylic acid 2,2,6,6-tetraalkyl-4-piperidinyl ester is at least one carboxyl group in the 2-position of the heterocyclic ring. Surprisingly, it was found that the 2,2,6,6-tetraalkyl-4-piperidinyl derivatives according to the invention

35

R? f-RO

- <N-Rl

^ _R10

40

45

50

or

R9

are in the

R7 to R10 Cr to C4-alkyl,

R7 to R8 or R9 and R10 together a tetra-pentamethylene bridge and

R11 is hydrogen, C2- to C] 6-acyl, Cr to Cs-alkyl, C3 to C8-alkenyl, C2- to C4-hydroxyalkyl or aralkyl and salts thereof.

Alkyl radicals for R1 to R3 and R7 to RlH and R'1 are CnH2n ^ | within the general definitions of the straight-chain or branched groups. The unbranched radicals are preferred. The following may be mentioned in detail, for example:

C «H17, CH, CH:

: cS -C7Hi5- Q, HI3, QH ,,.

55

60

65

CH,

CH.,

-CHi-CHo-CHcC ™ 3 CH .-- C CH ,,

Cri, ~ i

CH3

CH2CH e '^ 3, C (CH3) 3, CH ^ r ^ j3 preferably

CH3, C2H5, C3H7 or C4H,).

3rd

669 195

R5 is e.g. Benzyl, phenylethyl, 2,4-dimethoxyphenyl-ethyl, 2- (l-pyrrolidyl) ethyl, 2- (4-morpholinyl) ethyl, 2- (l-pi-perazyl) ethyl, cyclohexylmethyl or cyclohexylethyl.

Other residues Rn are e.g. Acetyl, propionyl, butyryl, hexanoyl, ß-ethylhexanoyl, allyl, ß-hydroxyethyl, ß-hydroxypropyl, benzyl or phenylethyl.

Bridge links A are e.g. Remains of the formulas

~ H2CH2CH2C-N ^ N-CH2CH2CH2-,

(CH: h0 (CH2) 20 (CH2) 3-, ~ (CH2) .r-N- (CH2) r

CH,

Preferred compounds of formula 1 have as

R1 to R3 are hydrogen or methyl and as

R7 to RU) methyl.

The derivatives derived from 2,4- or 2,5-di- or 2,4,5-trimethyfuran-3-carboxylic acid are particularly preferred.

Compounds in which R1 = R: = CHj and "R3 = H and R7 to RiH = CH are furthermore particularly preferred.

For R- "benzyl, phenylethyl or 2,4-dimethoxyphenylethyl are preferred. R" is preferably hydrogen, methyl, allyl, benzyl or acetyl.

The compounds according to the invention can be prepared by generally known chemical processes. The furan carboxylic acid piperidinyl amides can be e.g. either from the corresponding acid halides and the substituted 4-amino-2,2,6,6-tetraalkylpiperidines in the presence of acid-binding agents, such as organic amines, alkali metal hydroxides or alkali metal carbonates, or from the corresponding methyl or ethyl esters by reaction with 4-amino-2,2 , 6,6-tetraalkylpiperidines in the presence of catalytically active compounds such as titanium tetrabutylate. The amides are expediently prepared via the acid halides.

The preparation of the furan-3-carboxylic acid derivatives required as starting compounds is known from the literature. For example, the 2,5-dimethylfuran-3-carboxylic acid methyl ester can be prepared by the processes described in DE-OSes 22 07 098 and 28 26 013.

The 2-methyl-5-ethylfuran-3-carboxylic acid ethyl ester and corresponding esters with larger alkyl groups in the 5-position of the furan ring are described in J. Org. Chem. 43, 4596 (1978).

The ethyl 2-methyl-5-phenylfuran-3-carboxylate can be prepared according to the instructions in Bull. Soc. Chim. France 1970, [6], 2272.

The 2,4-dimethylfuran and 2,4,5-trimethylfuran-3-carboxylic acid methyl esters can e.g. according to the regulation in «Anales real soc. espan. fis. y quim. (Madrid) 50 B, 407-12 (1954) »[C.A. 49, 13 207 c (1955)].

The 2-methyl] -4-ethylfuran-3-carboxylic acid methyl ester can be prepared analogously to the 2,4-dimethylfuran-3-carboxylic acid methyl ester by using l-hydroxybutan-2-one instead of hydroxyacetone.

The synthesis of the 2-methylfuran-3-carboxylic acid methyl ester is described, for example, in DE-OS 28 00 505 or in J. Chem. Soc., Perkin Trans. I, 1981, 1982-9.

The preparation of further alkyl-substituted furan-3-car-bonic esters can be found in the literature.

The acid chlorides can be prepared by known methods, e.g. by saponification of the methyl or ethyl esters of the corresponding acids to give the free acids and their subsequent reaction with

Thionyl chloride or other suitable compound to the acid chlorides.

The compounds according to the invention can be in the form of the free bases or else as salts. Suitable anions are e.g. of inorganic acids and especially organic carboxylic acids.

Inorganic anions are e.g. Chloride, bromide, sulfate, methosulfate, phosphate or rhodanide.

Examples of carboxylic acid anions are: formate, acetate, propionate, hexanoate, cyclohexanoate, lactate, stearate, dodecyl benzoate, benzoate, acrylate, methacrylate, citrate, mononate or succinate as well as anions of polycarboxylic acids with up to 3000 COOH groups as well Anions of dialkylfuran carboxylic acids.

Details of the production can be found in the examples.

The compounds according to the invention are suitable for stabilizing organic material, especially plastics, against degradation by light and heat. They are added to the plastics to be stabilized in a concentration of 0.01 to 5% by weight, preferably 0.02 to 1% by weight, before, during or after the polymer formation.

All known devices and methods for mixing stabilizing agents or other additives into polymers can be used to mix the compounds according to the invention with the plastics to be stabilized.

The plastics stabilized by one of the compounds according to the invention can optionally also contain further additives, for example antioxidants, light stabilizers, metal deactivators, antistatic agents, flame retardants, pigments and fillers.

Antioxidants and light stabilizers which can be added to the plastics in addition to the compounds according to the invention are e.g. Compounds based on sterically hindered phenols or costabilizers containing sulfur or phosphorus.

Examples of such phenolic antioxidants are 2,6-di-tert-butyl-4-methylphenol, n-octadecyl-β- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 1,1, 3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-tri-methyl-2,4,6-tris (3,5-di-tert-butyl -4-hydroxybenzyi) -benzene, 1,3,5-tris- (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, 1,3,5-tris- [ß- (3rd , 5-di-tert-butyl-4-hydroxyphenyl) -propionyIoxyethyI] isocyanurate, 1,3,5-tris (2,6-dimethyl-3-hydroxy-4-tert-butylbenzyl) isocyanurate , 'Pentaerythritol-te-trakis [ß- (3,5-di-tert-butyl-4-hydroxy-phenyl) propionate] etc. mentioned.

Examples of phosphorus-containing antioxidants are tris (nonylphenyl) phosphite, distearylpentaerythritol diphosphite, tris (2,4-di-tert-butylphenyl) phosphite, tris (2-tert-butyl-4-methylphenyl) phosphite , Bis- (2,4-di-tert-butylphenyl) pentaerythritol diphosphite, tetrakis (2,4-di-tert-butylphenyl) -4,4'-biphenylene diphosphite etc. mentioned.

Examples of sulfur-containing antioxidants are dilauryl thiodipropionate, dimyristyl thiodipropionate, distearyl thiodipropionate, pentaerythritol tetractis (β-lauryl thiopropionate), pentaerythritol tetrakis (β-hexylthiopropionate) etc.

Other antioxidants and light stabilizers that can be used together with the compounds according to the invention are e.g. 2- (2'-hydroxyphenyl) benzotriazoles, 2-hydroxybenzophenones, aryl esters of hydroxybenzoic acids, a-cyanocinnamic acid derivatives, nickel compounds or oxalic acid dianilides.

Examples of organic polymers which can be stabilized by the compounds according to the invention are:

5

10th

15

20th

25th

30th

35

40

45

50

55

60

65

669 195

4th

Polymers of mono- and diolefins. such as. Low or high density polyethylene, linear low density polyethylene, polypropylene, polyisobutylene, polybutene-1, polymethylpentene-1, polyisoprene, polybutadiene and copolymers of mono- or diolefins or mixtures of the aforementioned polymers;

Copolymers of mono- or diolefins with other vinyl monomers such as e.g. Ethylene-alkyl acrylate copolymers, ethylene-alkyl methacrylate copolymers, ethylene-vinyl acetate copolymers or ethylene-acrylic acid copolymers;

Polystyrene;

Copolymers of styrene or a-methylstyrene with dienes or acrylic derivatives, e.g. Styrene-butadiene, styrene-acrylonitrile, styrene-ethyl methacrylate, styrene-butadiene-ethyl acrylate, styrene-acrylonitrile-methyl acrylate;

ABS, MBS or similar polymers;

halogen-containing polymers, e.g. Polyvinyl chloride, polyvinyl fluoride, polyvinylidene fluoride and their copolymers;

Polymers derived from α, β-unsaturated acids and their derivatives, such as polyacrylates and polymethacrylates, polyacrylamides and polyacrylonitriles;

Polymers derived from unsaturated alcohols and amines or their acrylic derivatives or acetals, such as polyvinyl alcohol or polyvinyl acetate;

Polyurethanes, polyamides, polyureas, polyesters, polycarbonates, polysulfones and polyethersulfones.

Other organic polymers that can be stabilized with the compounds according to the invention are

industrial paints. Among these are stove enamels, among them in turn vehicle paints, preferably two-coat paints. Of particular note.

5 The antioxidants and light stabilizers already listed can also be used here.

Insofar as they are solid, the compounds according to the invention can be added to the lacquer in solid or dissolved form or, if they are liquid, in bulk. Their good solubility in coating systems is of particular advantage.

Preference is given to using the compounds according to the invention in polyolefins, preferably ethylene and propylene polymers.

15

example 1

2,5-dimethylfuran-3-carboxylic acid-N-phenylethyl-N- (2,2,6,6-tetramethyl-4-piperidinyl amide)

28.6 g (0.18 mol) of 2,5-dimethylfuran-3-carboxylic acid chloro-20 rid and 45.0 g (0.18 mol) of 4-N-phenylethylamino-2,2,6,6-te-tramethylpiperidine are refluxed in 400 mol of toluene together with 15.0 g of sodium carbonate for 24 h. The mixture is allowed to cool and the precipitate is filtered off with suction. This is stirred for 0.5 h in 1000 ml of 2N sodium hydroxide solution, and the mixture is extracted with 25 ethyl acetate. The organic phase is concentrated, the remaining residue is dried. 46.2 g (72%) of a colorless compound of mp 76 to 78 ° C. are obtained.

Further compounds according to the invention are listed in Table 1; the designations refer to Formula I.

Table 1

E.g.

R1

R2

R3

R **

Melting point

CH3

ch3

0-H2C-N- <;

nh

78 - 80 ° C

ch3

ch3

h3

ch3

ch3

ch3

ch3

30 - 132 ° C

"3 C0 —— CH2CH2 — N—

ch3

ch3

|: C H 2 C H 2 N— ^

I.

NH

CH2-N ^, N- (CH2) 3_N-CH 2

I-

ch 2 n

I W-

NH

4 "

I W-

HH

96-98 ° C

Bp 168 ° C / 0.1 Torr

Mp: 1 25-1 27 ° C

I0 0 C

H3O ^ mv \ CH3

5 669195

Example 7

9

as example 1, salt with 2,4-di

178-

-180

C.

10.0 g of the carboxamide from Example 1 are in

methyl furan-3-carboxylic acid

150 ml of methanol dissolved. Add 1.92 g adipic acid,

10th

as example 2, salt with Adi

83-

- 85 "C.

warms up to a clear solution and constricts. You get

pinic acid

11.3 g (95%) of the adipic acid salt with a mp

5 11

as example 2, salt with 2,5-di-

162-

-163

° C

154-156 ° C.

methyl furan-3-carboxylic acid

Further compounds according to the invention are in Ta

12

as example 1, salt with 2,4-di

148-

-150

° c belle 2 listed; the designations refer to For

methyl furan-3-carboxylic acid

mel I.

13

as example 3, salt with Adi

80-

- 83

° c

10th

pinic acid

Table 2

Ex. R4 melting point

8 as Example 1, salt with 2,5-di-138-140 ° C methyl furan-3-carboxylic acid

C.