GB2339779A

GB2339779A - 2,6 Quinoline Derivitives

Info

Publication number: GB2339779A
Application number: GB9815537A
Authority: GB
Inventors: John William Goodby; Kenneth Johnson Toyne; Robert Andrew Lewis; Michael Hird; Andrew John Slaney; John Clifford Jones
Original assignee: UK Secretary of State for Defence
Current assignee: UK Secretary of State for Defence
Priority date: 1998-07-17
Filing date: 1998-07-17
Publication date: 2000-02-09
Also published as: GB9815537D0

Description

2339779 2,6-Ouinolines The present invention relates to quinoline

compounds, and particularly but not exclusively to such compounds which 5 possess a liquid crystal phase.

Quinolines have received relatively little attention as mesogenic cores for liquid crystal materials. Nevertheless, materials of the general formula (1) R, R2 are known, where one of RI and R, is alkyl and the other is alkoxy, examples thereof being disclosed in Liquid Crystals, 2, (1987), No 5, pp 625-31 and in Ferroelectrics, 148 (1993) 139-145.

Also, materials of the general formula (2):

CH2=CH.(CH2)90 N OC,H2n., 20 where n is 4, 6, 9, 10, 12 or 14 are disclosed in Liquid Crystals, a, (1997) No. 5, 661-7.

In addition, materials of the general formula (3) CnH2n,10 N:Z Nll N 60" N H OCnH2n., ..... (3) where M is 5 and n is 1 to 10 are disclosed in Liquid Crystals, 20, (1996), No. 2, 253-260, and materials of the general formula (4) 0 11 H2"lCnO O-C-0 N C6H13 (4) where n is from 3 to 9 are disclosed in Mol. Cryst. Liq.

Cryst., 206, (1991), 131-137.

Where negative dielectric anisotropy is required, the presence of the nitrogen atom inherently creates a transverse dipole moment. The presence of a fluorine atom in the molecule can have a significant effect on the liquid crystal properties in general, including the dielectric anisotropy, which can be increased or decreased according to whether the dipole moment associated with the fluorine atom aids or opposes that associated with the nitrogen atom.

2 Accordingly, in one aspect, the present invention provides a 2,6-quinoline derivative comprising a group R.-A- at the 6-position and a group R,-B- at the 2-position, wherein RI and R, may be the same or dif f erent and are each selected from an alkyl or alkoxy group, which may or may not comprise further substituents, may be saturated or unsaturated, branched or straight chain; an aryl group substituted with an alkoxy or alkyl group, wherein either of the aryl and alkyl/alkoxy groups may or may not comprise further substituents, and the alkyl or alkoxy group may be saturated or unsaturated, branched or straight chain; a nitrile group; and a trifluoromethyl group; wherein at least one said alkyl or alkoxy group is present; wherein A and B may be the same or dif f erent, and are each selected f rom a direct bond, or a linking group providing a linking chain length of up to f our atoms between the quinoline nucleus and the respective substituent R, or R.; wherein, excluding any terminal hydrogen atom, the, or at least one, said alkyl or alkoxy group (a) provides a maximum chain length of no less than four atoms and no more than 16 atoms if joined directly to the quinoline nucleus, or if substituted on a said aryl group; or (b) if joined to the quinoline nucleus by a said linking group A or B, provides with the said joining group a chain length of at least 4 atoms and no more than 16 atoms extending from the quinoline nucleus; and wherein at least one of the quinoline nucleus, the R,.-Acombination and the R,-B- combination includes a fluorine substituent.

3 None of the prior art compounds mentioned above comprises an aryl group directly substituted at the 6 position on the quinoline nucleus, and accordingly, in a second aspect, the invention provides a 2,6-quinoline derivative comprising a group R,-A- at the 6-position and a group 1?,-Bat the 2- position, wherein R, and R, may be the same or dif f erent and are each selected f rom an alkyl or alkoxy group, which may or may not comprise further substituents, may be saturated or unsaturated, branched or straight chain; a nitrile group; and a trifluoromethyl group; wherein at least one said alkyl or alkoxy group is present; wherein A is an aryl group; wherein B is selected from a direct bond and a linking group providing a chain of up to four atoms between the quinoline nucleus and the respective substituent R2; wherein, excluding any terminal hydrogen atom, the maximum chain length of the group R, and/or the maximum chain length of the group R,-B- is no less than 4 atoms and no more than 16 atoms.

Also, in a third aspect similar to the second, the 25 invention provides a 2,6-quinoline derivative comprising - a group R,-A- at the 6-position and a group P,-B- at the 2-position, wherein R2 and R, may be the same or dif f erent and are each selected f rom, an alkyl or alkoxy group, which may or may not comprise further substituents, may be saturated or unsaturated, branched or straight chain;.a nitrile group; and a trifluoromethyl group; wherein at least one said alkyl or alkoxy group is present; wherein A and B are aryl groups which may be the same or different; and 4 wherein, excluding any terminal hydrogen atom, the maximum chain length of the group R, and/or the maximum chain length of the group R. is no less than 4 atoms and no more than 16 atoms.

In each case, where present, substituents on R, and/or R, will in general be relatively small groups, for example a methyl group, a trifluoromethyl group, a halogen atom, a nitrile or amino group, or possibly a methoxy group.

Where present, additional substituents on the quinoline nucleus will in general also tend to be relatively small, for example a halogen atom, a nitrile or amino group, a methoxy or ethoxy group, or a methyl or ethyl group.

Where present, the aryl group included in R, or R, is commonly a benzene ring, although it could be, for example a heterocyclic ring system such as pyridine, pyrimidine or thiophene.

Where present, the linking group A/B could provide, for example, a single atom chain such as sulphur (-S-), carbonyl (-CO-), amino (-NH-) or methylene (-CH.,-); or a double atom chain, such as vinyl (-CH=CH-), acetylene or ethynyl (-C=-C-), carbonyloxy or oxycarbonyl (-COO- in either direction). Groups providing three or four atom chains can also be used (for example -CHCOCH,- and -CH,CH=CHCH.- for coupling to- an aryl nucleus). In some preferred materials both A and B are direct bonds.

Liquid crystal properties tend to be associated with molecules which can adopt a shape which is rather long, and tends to be narrow or flat, and it is believed that the requirement for chain lengths of 4 to 16 atoms, and preferably 5 to 10 atoms, associated with the alkyl/alkoxy groups optimises the chance of liquid crystal phases without giving a molecule which is so large that the material becomes unusable, e.g. by virtue of the narrowness or elevation of the liquid crystal temperature range.

Furthermore when R3. or R, comprises an aromatic nucleus, it is believed that conjugation with the quinoline system will tend to increase the overall flatness of the molecular shape. When there is an intervening linking group, those providing two or four atom linking chains are preferred to favour a flat linear conformation, particularly when such linking group also permits conjugation between the aryl nucleus and that of the quinoline, e.g. by virtue of being unsaturated.

By appropriate choice of alkyl or alkoxy group, or A or B, or any additional substituent, which is optically active, the entire molecule can be made chiral. This is well known to affect the properties of any resulting liquid crystal phase.

While it can be expected that the type of joining group A and/or B will have some effect on dielectric anisotropy, the presence of the fluorine substituent is expected to have a much greater effect.

In one preferred embodiment the quinoline nucleus comprises at least one fluorine atom, on the 3, 4, 5, 7 or 8-position, the latter being illustrated in some embodiments described below. When present at the at the 8- position, a fluoro- substituent provides both a higher dielectric biaxiality and a lower melting point, e.g.

-compared to the non-substituted equivalent, but other positions for'a fluorine substituent or substituents on the quinoline nucleus fall within the present invention. Thus, additionally, or in lieu thereof, where present an aryl group can be substituted with at least one fluorine atom, and ' some embodiments described below comprise two fluorine atoms on an aryl group.

6 Where present, a preferred form of aryl group is a benzene ring, and this, in some embodiments described below, is substituted by a single fluorine atom, or by two fluorine atoms on adjacent carbon atoms of the ring.

Also, as in some embodiments below, a benzene aryl group is substituted by a said alkyl or alkoxy group in the para-position.

In a derivative according to the second aspect, B is preferably a direct bond.

In some preferred derivatives according to the invention, R, is an alkoxy group and R, is an alkyl or alkoxy group.

The invention extends to methods of preparing derivatives according to the first to third aspects, including in particular a method in which an ethynyl linkage A is reduced to a saturated linkage. it also extends to liquid crystal materials and compositions comprising derivatives according to the first to third aspects, and to devices containing such materials, for example light modulators, and particularly, but not exclusively Electro-optic light modulators and display devices.

Further aspects and features of the present invention will become clear on consideration of the appended claims, to which reference should be made, and on consideration of the following description of exemplary embodiments of the invention.

Using the following reacti on scheme, a number of compounds of the formula (5) and/or (6) were prepared:

7 Scheme 1 a Br N Br- -NH2 0 2 3 b x C Ic a N Y N 5- 4 a.-. (i) 6M 1(3, (ii) ZnC12, (iii) NH3 b... alyrooronic acid, 1,2- diinetboxyediane, 2M Wa2CO3, Pd(PPb3)4 c- (i) n-butylUdiium or lithiumdiisopropylamide, TBF (ii) alkylbmmide Compound x Compound x y 4a CsHt?O- CgHI70--o- n-beptyl -9b 4b C$F-l-P CSF-170- F 4c CgH.70 5C CSH n-heptyl 5d CSH170 5e 'qH,-p 02 C.-HI-P-02 dec-10-eiryl 9 Scheme 2 a CAUI I,;:: Ml C7H,5--o-NH2 6 7 N b a---C0W-H2SO4,glycerokFeS CA15 boricacid, F N sodium 3-aitmbenzenesulponate b... ri-butylithiuM 4-bro#4-octylo)q,2-ffwmbcnzene,TBF OCS HI-7 Scheme 3 F B C,DH210 Br- M2 a b N F 10 N C a COW- H2SO4, glycerok FeS, ClOH21 boric acid, so4rum 3-nMvbcn=nesulpbonaft b 4-decyloWbewlbownic acid, 1,2-dimeffioxyedwie, 2M Pd(PPh3)4, 2M Na2CO3 b n4wxyffitbiurv T. BF 12 F NCj!13 I Scheme 4 F sq,70- F Br;ZZL 5 1 1 1&; F CaBr 13 F N 14 ItH17 a --- 4-mVIoxy-2,3-dfflwmpheaylboronic acid, U-dimethoxyethaw, Pd(PPh3)4, 2M Na2CO to Experimnentat Melting points and liquid crystal transition temperatures were measured using a Mettler FPS hot-stage and control unit in conjunction with an Olympus BH2 polarising microscope. These were confirmed by differential scanning calorimetry (DSC) carried out on a Perkin Elmer DSC 7 with TAC 7/PC instrument interface and controlled cooling accessory. Heating and cooling rates were at 10 'C mirrI. A nitrogen atmosphere was maintained in the firnance. The refesence sample was gold and the calibration sample was indrurrL The transition temperatures are given for the heafing cycle and'melting points for liquid crystalline compounds are those of the DSC onset value. Analytical thin4ayer chromatography (TLC) was performed on KiescIgel silica gel 60 F254, backed onto aluminium. sheets and spots were visualised with UV light and iodine. The progress of reactions was often monitored using a Perldn Elmer 93 10 capillary gas chromatograph fitted with a 12 m QC2/BPI-1.0 SGE colunin (N2 carrier) and a flame ionisation detector. Purity of compounds -was checked by bigh perforniance liquid chromatography OPLC) on a Licbrocart 125-4 Superspher RP IS column connected to a Merck-Hitachi L4000 UV detector, L 6200A pump, D-6000 interface and D-6000 HPLC manager eluting with chloroform/acetonitrile. Infi-ared (IR) spectra were obtained using either a Perkin Elmer 993G or a Peridn Elmer 497G -spectrometer (s = stronp, w = weak) as thin lihns or potassium bromide discs. 'H NM spectra were recorded on a JEOL JMK G3M70 FT spectrometer (270 MITz) in deuteriochloroform -unless otherwise stated. Chemical shifts are reported in ppm from an internal standard of IMS. Selected data are reported as follows: chernical shik multiplicity (s = singlet, d = doublet, t = triplet, q = quartet, -m = multiplet, br broad), coupling constarit Qmtz) and assiganxmt. Mass spectra were recorded on a Firrinigan MAT 1020 GC/MS spectrometer, W represents the molecular ion. Flash chromatograpky was carried out using Sorbsil C60 (40- 60 m) grade silica- TBF was fresI4'distilled from potasmum/benzophenone ketyl and AnalaR ether'was dried over sodium wire.' Light petroleum refers to the fi-action (b.p. 40-60 'C) unless odxxwise stated. Organic solvent extractions were dried over magnesium sulphate unless otherwise stated. The syringe pump employed in the synthesis of the bromorriethylquinoline 3 was a Razel A-99 model.

6-B,ronw-2-vYeIqzdWine 3 A solution of 4-bromoanfline 1 (50.0 g, 0-291 mol) and 6M hydrochloric acid (145 ml) was heated under gentle refhm -A mb"re of crotonaldehyde 2 (30.5 K 0.37 mol) and n-butanol was added'Wa a syringe pump at -a -rate of 6 ml W. After the final addition -the mixture was heated under reflux for 30 miri; zinc chloride (39.6 g, 0.29 mol) was added to the hot mixture which was heated for 5 min and cooled to 0 C- A tarry precipitate was filtered off and washed with propan-2-ol to leave a yellow solid which was then washed with THF and ether. The quinaldine HCI(ZnCI)v2 complex was partitioned in conc. ammonia-ether and the aqueous layer was extracted with ether The combined organic extracts were dried and evaporated to give a yellow crystalline solid 3 (3 1.0 g. 480/6); 8;i 2. 55 (3 H, s, Me), 7.29 Q H, d, J 8-5, 3-H), 7.74 (1 K dd, J 9 and 2, 7-H), 7.89 (1 K d, J9, 4- or SH), 7.92 (1 H, d, J 2, 5-H), and 7.95 1 IL d, J 9, 4- or 8-H); 2-Me1-6-(4'-"Iox>phenyl)quinoline 4a 6-Bromo-2-methylquinoline 3 (2.79 g, 12-6 mmol), 4-octyloxyphenylboronic acid (3-77 g, 15-1 rnmof) and tetralds(triphenylphosphine)-paWium(o) (437 mg, 0.30 nunol) were added to a mixture of 1,2-dimetboxyetharte (50 ml) and 2M aqueous'sodiurn carbonate (50 mI)- The inbcture was degassed and heated under gentle reflux in a nitrogen atmosphere for 4 IL The product was extracted into dichloromethane (2 x) and the extracts were washed with sat. aqueous sodium chloride, dried and evaporated- Flash chromatography (300/a ethyl acetatelight petroleum) gave.a pale yellow solid 4a (3-49 g, 781%) (from MeOM; v,,,'2950, 2930, 2920, 2970, 2850- 1600, 1595, 1515, 1490, 1295, 1210, 93 0, and 820 crrf'; &'J 0. 89 (3 IL t' Me), 1.25-1.57 (10 K m, CH2), 1-82 (2 K quint, OCH:zCH2), 2.76 (3 IL s, 2-Me), 4.01 (2 K t, OM2), 7.01 (2 R d, J 9, 3'- and Y-H), 7.29 (1 K J 8. 3-M, 7.64 (2 K d, J 8, 27- and 6'H)..' 7.90, (1 K s, 5-M, 7.92 (1 K dd, J 8 and 2, 7-M, 9.04 (1 K d, J 8, 4- or 9-M, and 8.07.(I K d, J8, 4- or 8-M; m1z 347 (M+I, 333, 313,.261, 248, and 235. 6-(2',3-Witoro-4'-octyloxyphetod)-2-,methylquinotine 4b Quantities: 6-bromo-2-methylquinoline 3 (2.01 g, 9.05 mmol), 2,3difluoro4octyloxyphenyThoronic acid (3.37 & 11.7 mmol), tetdbs(tripheuylphospMne)pa%diurn(O) (314 mg. 0-27 minol), 1,2dimethoxyedmie (50 ml), 2M aqueous soidium carbonate (50 ml). The experimental procedure was as described for 2-methyl-6-(4'octyloxyphenyl)quinotme 4X_ Flash chromatography (10 to 35% EtOAc-light petroleum) -gave the pale yellow methl )Apinoftne 4b (2.51 g, 70%) (from MeO14; v..,.- 2950, 2920, 2850,1625, 1600, 1515, 1495, 1460, 1300, 1100, 1070, 945, 810, and 795 cnf'-, 6a 0. 89 (3 IL t, CH2CH3), 1.24-1.43 (8 IL tn CH:z), 1.49 (2 K quint, OCHM- 2CH2), 1-85 (2 K quint. OCH2CH2), 2-55 (3 K S Me), 4.09 (2 _K 4 0012), 6,84 (1 K ddd, J 8, 7-5 and 2, 5'41), 7.19 (1 dt, J 8 and 2, 6 MI, 7.31 (1 K d J9,3-1p, 7.82 (1 IL dt, J9 and 1.5, 7-H). 7-90 (1 br 5-1p, and:9.08 (2 FL d, J 9, 4- and &-M; m1z 383 (M), 271 (1 W1.), 256, and 222.

_(27 _f7UQrO411_"jOX)phCjDO_2 YjqUjWjjnC 4C _Mejh Quantities: 6-bromo-2-methylquinoline 3 (15.2.g- 68.6 mmol). 2-fluoro4- octyloxyphenyl boronic acid (27-6 g, 103 mmol), teb-4]ds(triphenylphosphine)palladium(O) (2.38 g, 2-04 unnol), 1,2-dimedKmyethane (200 ml), 2M aqueous sodim cmbonate (200 ml). The expenmental procedure was as descnl)ed for 2-Tncthyl-6-(4'- octyloxyphenyl)qumohne Flash chromatography (20/ EtOAc-light petrolmn) gave the pale yellow'medifyquinoline 4C (20.5 g, 8r1e) (from MeOM; transitionsrC C 56.3 N 59-9 1, v..,_ 2960, 2935, 2920, 2900, 2860, 2950, 1610, 1510, 1460. 1295, 1160, 1115, 1035, 960, 950, and 830 cni"; &_ 0.90 (3 FL s, Me), 1.25-1.42 (8 K m, CH:z),, 1.48 (2 It quint OCHzCH2CH2), 1.82 (2 K quint, OCH2CH2), 2.76 (3 K s, CCH3), 4.01 (2 K t, OCH2), 6.75 (1 K dd, J 13 and 2, Y-M, 6-80 (I K dd. JS and 2, 5'-MP 7.29 (1 FL d, J9,3-M 7.44 (1 -K t, J 8-5, 6'-H), 7.85 (1 K dt, J9 and 2, 7-H), 7.90 (1 K br s, 5-M, 8.05 (1 YL d, J 9, 4- or 84D. and 8.06 (1 d, J 9, 4or 8 M/Z 365 347, 334, 314, 360, 297, 253, and 197.

2-Heptyl-6-(4'-octyloxypheWI)quinoline Sa To a cooled (-10 C) degassed solution of2-metbyi-6-W- octyloxyphenyl)quinofine 4a (1.90 g, 5.47 mmol) in dry TBF (30 ml) under Xjwas added 2_5M n-butyllitbium. (3.6 ral, 5.7 mmot) dropwise, maintaining the temperature at -10 -C_ A bri& red colourappeared inimedeiately on addition of n4xrt3ihthium and after the final addition, stirring was continued with cooling for 30 min. I-Bromohexane (947 ing, 5. 74 mmol) in TUF (3 nil) was added and the reaction was allowed to warm to room temperature overnight. Water was added and the rabaure was extracted into ether; the extractions were washed with sat. mpeous sodium cMondc, dried and evaporated. Flash chromatography (10% EtOAc-liglit petroleum) gave the keptylquinoline Sa 1-29./o).(from EtOAc); ftansitionsM C 101.9 SmA 125.6 L- (Found: C. 83.48; H, g, 551 9.83; N, 3-30. C-,olLINO requires C, 83.48; K 9.57; N, 3.25/Y, v.,, 2960, 2920s, 2855, 1600, 1515, 1490, 1280, 1260, 1245, 1190, and 830 cm-'; m1z 431 (W), 402, 374, 360, 347, and 234.

6-(2',,3.'-Difluoro4'-"Iolg,pheloo-2-h--ptylqWnoline 5b Quantifies: 6-(2,3'-Muoro4'-octyloxyphenA2-metbylquinoline 4b (1.50 g' 3- 80 rnmol), Ibromobexane (627 mg, 3.80 mmol). 2.5M n-butyllithium (1.6 nd, 4.0 mmol), TFIF (30 ml). The experimental procedure was as described for 2-heptyl-&(4'-octyloxyphenyT)qumohne 5aFlash chromatography (10 to 15% EtOAc4i& petroleum) gave the heptylquinolim 5b (0.97 556/6) (from MeOHMOM; transitionsrC C 42.4 SmA 73-7 1 (Found: C, 76-76; K 9.72; N, 3.03. C3aH39NOF2'requires C, 77.04; K 8.41-114, 3.0(r/o); v. 2950, 2920s, 2870, 285Q, 1630, 1600,1515, i495,1410,1500,1200w, 1100, 1075s, 8845, and 795 cfff'; 6. 6.87 (3 H, t, Me), 0.90 (3 K s, Me), 1.24-1.56 (18 CH2), 1,83 (2 K quint, CH7.), 1-86 (2 I-L quint Cu6), 2.98 (2 K t, J 7-5 ' CCH2), 4. I'D (2 K t, J 6, OCH2), 6-84 (1 It ddd, J 8.5, 8 and 2, 5'-1P, 7.20 (1 TL dd J 8.5 and 2, 6'-M. 7.33 (1 H, d, J 9, 3-1p, 7.92 (1 K dt, 19 and 2, 74P, 7.91 (1 IL br t, 5-M and 8-09 (2 ET, d, J 9, 4- and 9-M; m/z 467 (NO, 438, 424, 410, 3967 393, wW 271.

6-(2'-Flito,ro-4'-"IogpheMD-2-heptylquinoline 5c Quantities: 6-(2'-fluoro4'-octyloxyphenyIY2-metbylquinoline 4c (5.0 g, 13.7 nunol). Ibromohexane (2-37 g, 14.4 mmol). 2.5M n.-Wfithium. (6.0 t-W, 14.4 mmol)." TBF (100 Ud). The experimental procedure was as descnlx4 for 2-h"1-6-(4'octy]oWhenyl)quinoline SaFlash chromatography (0 to 15% dichloromethaneligk petroleum) gave -the heptyfquinohne Sc (2-44 9. 406/6) (from EtOM; trwLsitions/0C C 40-6 SmA 69.3 1 (Found: C, 79.96; K 9- 11 N, 3-10. CmH4oNOF reqes C, 80.13; K 8.97; 3.120/9); v...,'_ 2970, 2920, 2850, 1620, 1510, 1490, 1460, 1310, 1225, 1160,; 1120, 910A 850, and 830 cyW'; 8a 0. 87 (3 FT, t, Me), 0.90 (3 It t Me), 1.23-1.53 (18 K m. CH2), 1.8 1 (4 K overlappling quint, CH2), 2.97 (2 K t, J 7- 5, CCH2), 3.99 (2 K t, J 6, OCH2). 6.74 (1 K dd J 13 and Z, 3'-M, 6-80 (1 K dd, J 8 and 2 5'-M, 7-32 (1 IL d, J 9, 3-14), 7.44 (1 IL dd, J 9, 6'-M, 7.85 (1 K dt, J 8 and 1.5, 7ID. i'6. (I IL br s, 5-H), and 9.07 (2 K d, J 9, 4- and 8-ID; m1z 449 OW), 420, 406, 392, 378, 365 (IW19), and 253.

2-(co-Bromalievl)-6-(4'-"IoWhenyr)quinoline 5d Quantifies: 2-methy"44-octyloxypbenyl)quinoIine 4a (1.20 g, 3-46 nunol), 1,5 dibrornopentane (398 mg, 1.73 mmol), 2.5M n-butyllithiurn (1.5 ml, _3'6 mmol), TUF (30 rnl).

The experimental procedure was as descnl)ed fbr 2-hept3d->-Koctyloxyphenyl)qtiii61ine Sa.

Flash chrornatography. (10 to 200% ROAc-light petroleum) We the bromohexyAqvinoUrze 5d (120 mg, 54/) (from R01-1); transitions/'CC 71.3 SmA98.6Lv.,.2920,2850, 1600,1515, 1490, 1460, 12:90, 1245, 1190, 1030, 1000, 895' and 830s, cid'- Sa 0.90 (3 H, t, Me), 1.24 1.57 (14 K ta, C116), 1.85 (6 K 3 x quint CH2), 2.99 (2 K t, j 7. 5, CMzj, 3.41 (2 I-L t, J 7, Cff2Br), 4.02 (2 K d, J 6.5, OCH2), 7.01 (2 9 d, J 8, 3'- and 5'41), 7.30 (1 It d, J 9. 3-M, 7.64 (2 K d, J 8, 2'- and 6'-M, 7.90 (1 K d, J 2, 5-H), 7.92 (1 FL dd, J 9 and Z, 7-M, 8.07 (I K (L J9,4-,or 84D, and 8-09 (1 IL d J 9,4- or 8-M; m1z 497.495 O\Of), 482, 469, (M), 452, 417, 361 and 348 (100%).

2-((D-Bromohepfyo-"4'-ocfylo-rjphenyl)quinolin 5c 2_5M n-Butyllithium (3. 5 ml, 8.6 mmoD was added to solution of dry diisopropylamine (1.1 ml, 8.6 mml) in dry TBF (40 ml) under N2 at -70 'C. After 5 min 2-metby16-(4'octyloxyphenyl)quinoline 4a (3.0 g, 8.6 mrwl) in THF (5 rnl) was added dropwise and 13 stirring at -70 C continued for 40 min1,5-Dilbromohexane (2.1 g- 8.6 mmol) in TBF (5 ml) was added to the deep red solution and the reaction was allowed to warm to ambient temperature overnight. Water was added and the product was extracted into chchloromethane. The combined organic extracts were washed with water, dried (Na-,-'o X and evaporated-. Flash chromatography (5 to 10% EtOAc-light petroleum) gave the bromoheplYlquinoftne 5e (2-38 g, 54/o) (from EtOAc),-, transitions/0C C 89-9 SmA 98-1 1 (Found: C, 70.62, K 8.00; N. 2.62. C3jLwNOBr requires C, 70.70; K 7.92; N, 2-751K), v - M= 2920, 2850,1600, 1515, 1490, 1460. 1280,1260, 1245, 1190, 1130, 1030, 1000, and 830 crrf 1; 82 0.90 (3 K t, Me), 1.25-1.53 (16 It in, CH2), 1. 87 ( H, 3 x quint, CH:t), 2.98 (2 K t, J 8, CCH2). 3 -40 (2 K t, J 7. CH2Br), 4.02 (2 K dx J 6.5, OCH2), 7.01 (2 K d, J 8, 3'- and 5'ID, 7.30 (1 K d, J 9, 3 IP, 7.63 (2 H, d, J 8, T- and 6'-H), 7.90 (1 K br d J 2, 5- M, 7.92 (1 K d4, J 9 and 2,1-1p, 8.07 (1 K d, J 9, 4- or 8-H), and 8.09 (1 11, d J 9, 4- or;g-H); m1z 511 (M), 509 (M-), 481, 431, 416, 402, 375, 360, 347 (1000/.), and 234.

2-(Dodec-10-enyl)-"2-flU,DrO-4'-octyloWhenyl)quinoline 5f Quantifies: 6-(2'-fluoro-4'-octyloxyphenyl)-2-metbylquinoline 4c (2.50 g, 6.95 mmol), I Ibromoundec-I-ene. (1.65 g, 6.95 mmol), 2.5M n-butyllithium (2.8 nil, 7.1. mmol), dfisopropylamine (420 mg- 7-1 mmol), TBF (30 nil). TheoqxTimeutal, procedure was as described for 2-(w-bromobeptyp-6-(4'octyloxyphenyr)Winoline Se- Flash chromatography (5 to 100/q EtOAc-light petroleuR) gave the dodecenylquinoline 5f (2-49g, 620%) (from EtOH); transitions/OC C 44.6 SmA 62.9 1 (Found: C, 8 1.42; K 9.7 1; N, 2.69. C35FLaNOF requires C, 72.63; K 9.54; N, 2.421/e); v..,- 2920, 2840, 1615, 1510, 1485, 1460,"'1300, liZ5, 1165, 1_120,1100, 960, 905, 930, and 820 cm4; SH 0.90 (3 IL t, Me), 1.2'3-1.57 (24 K m, CH2), 1.8 1 (4 IL 2 x quint, CH2), 2-04 (2 I-L q. CHM=CH2), 2.98 (2 K t, J 7, CCH2), 3.99 (2 K d J 6.5, OCH2), 4.92 (1 K d of m, 12-H.), 4.98 (1 I-L d of m, 12-1-L&), 5. 81 (1 K ddt, Jv.,,,- 14, J,,,i,: 1q, and 6, 1 I-M, 6.75 (1 K dd J 13 and 2, 3'-H), 6.80 (1 K dd J 8 and 2, 5% 7-31 (1 K d, J 8, 3-M, 7.44 (1 H, dd, J8, 6'-1-1), 7.84 Q K dt, JS and L5, 7-M, 7.90 (1br s, 5-M, and 9.08 (2 K d, J8, 4- and &M; m/z Sig (W+I) 489, 477, 463, 421, 379, 366, and 254 (100%).

6-HiTfyWnofine 7 A nixture of 4-heptylanaline 6 (20.0 g.. 0.105 mol). glycerol (24-3 ml), iron(D) suIphide (3.03 g, 0.034 mot), sodiurn 3-niftobenzenesulphonate (11. 1 g, 0-049 mol), conc. sulphuric acid (18 ml) and boric acid (5.36 g. 0.087 mol) was heated at ca.'145 C (reaction temperature) for 3hThe appearance of vigorous fi-othing indicated when the temperature required for reaction had been attained. Water was added and the mixture was made basic with dilute sodium hydroxide solution. The dark mixture was extracW with &Jxr, the combined extracts were washed with sat. aqueous. sodium chloride, dried. and evapomted. Distillation (Kugelrohr, 170 'C:' 0-9 rnmHg) gave the pale yellow heptylquinoline 7 (19.1 g, 801/6); v..,,.- 2950,2920, 2850,1590, 1565, 1,495s, 1460, 1375, 1120, 980, and 785 cm-; 6p. 0.90 (3 T-1, t, Me), 1.22-1.45 (9 H,.m, CH2). I - 75 (2 K quint ArCH2), 7.36 (2 FL dd, J 9 and 4, 3-M, 7.56 (2 K in, 5- and 7-M, 8.03 (1 K d, J9,4- or 8-EP, 8-08 (1 IL d J9,4- or 8-M. and 8-85 (1 K dd, J4 and 2, 2-M; ml-- 221 (M), 212, 198, 184, 167Y 156, and 142 (1 O(M).

2-(3 -Fluoro-4'-ocWoxyphenyl),-&heplylwimoline 8 1.6M a-Butyffithium (6.8 ml, 10.9 mmol) was added to a solution of 4bromo-l-octyloxy-2fluorobenzene (3.31 g, 10.9 mmol) in dry THF (40 ml) at. -70 C under N2. After Ih a solution of 6-heptylquinoline 7 (2.48 g- 10.9 mmol) in TBF (5 MI) was added droptise and the mixt"e was allowed to warm to room temoerature overnigbt. Sat- aqueous sodium chlodde was added and the organic layer was separated. The aqueous layer was extracted with ether and the combine - organic soltitions were dried and evaporated. Flash chromtograpby (4% ethyl acetate-light petroleum) gave the 2-tvylquinofine 9 (1-71 g, 351/0) (from EtOAc), transitionsrC C 46.5 SmC 82.5 SmA 95.6 N 97.4 L v.,,, 2950, 2920, 285q, 1620w, 1595, 1520, 1490, 1460s, 1285s, 1270s, 1135, 985, 840,:910, and 785 crn-'; Sjj 0.88 (3 K t, Me), 0.89 (3 K t, Me), 1.23-1.43 (18 K m, C112), 1.49 (2 K quint OCH2CH2CH2), 1.72 (2H, quint, CCH2CH2),1-86(2 EL quinOCH2CH2),239 (2K tJ-7.5, CCHZ). 4.10 (2Kt,J7,OCH2). 7.06(l K dJ9, 5'- 14), 7.56 (2K m, 3and 5-1-1),7.77(l K dJ9, 7H), 7.85 (1 K d of m,.J 9, 6'-M, 7.96 (1 K dd., J 12 and 2, 2'-1-1)7 8.04 (1 K d, J 9, 4- 'or 8M, and 9.12(l RdJ9,4-org-M;m/z449M),337,308,279. 266, and 252(1000/.).

6-Bromo-Sfluoroquiwlh 10 Quantities: 4-bromo-2-fluoro.analine 9.(9-5 g, 0. 05 mol), gjycerol (12-3 ml), iron(D) sulphide (1.44 g, 0.016 mol), sodium 3-nitrobenzenesLdphonate (4.79 g, 0-021 mol), conc. sulphuric acid (B ml), , boric acid (2.56 g, 0-041 mol). The experimental procediire was as described for 6-heptylquinoline ?. Column chromatography of the crude extract (0 to 200/o ethyl acetatelight petroleum) gave the bromofluoroqzdhohm 10 (3.60 g. 640/); 7.49 (1 FL dd), 7.55 (1 K dd 7.81 (1 K t), 8- 12 (1 K dt), and 8 99 (1 K dd)- 6-(4'-DecyIarjphenyV-8fluoroquinofine 11 Quantities: 6-bromo-8-fluoroquinofine 10 (1.60 g, 7-09 mmol), 4- decyloxyphenylboionic acid (2.16 g, 7.77 rnmol), t.ebakis(tjiphenyl- phosphine)palladium(O) (0.25 g, 0.22 - mmol), 1,2dimethoxyethane (35 ml), 2M aqueous sodium carbonate (35 ml)- The experimental procedure was as described for 6-(4'-octyioxyphenyt)-2-methylquinotine 4a- 'Flash chromatography (0 to 5WI. dicliloromethane-light petroleum) gave the flUOrOCflYIqUinOUJ7e 11 (1 -50 g, 565/e) 2960, 2930, 2920s, 2870w, 2950, 1600, 1490, 1375, 1280, 1270, 1255, 1245, 1200, 1090, 1020, 990, 970, 835s, and 790 crif'; &S 0.89 (3 H, t Me), 1.25-1.56 (14 T-T, m, CH:z), 1. 82 (2 K quint, OCH2CH2), 4.02 (2 IL t', J 6.5, OCH2), 7-02 (2.K d, J 9, 3'- and 5'-M 7.48 (1 K dd, J 8 and 4, 3-1p, 7.62(2 IL d, J 9, 2'- and 6'- Ip, 7-67 (1 K dd, J 13 and 2, 7-H), 7.75 (1 K d, J 2 5-11), 8.20 (1 IL dt, J 9 and 1.5, 4-H), and 8.93 (1 K dd, J 6 and 2, 2-M; m/z 379 Qd), 23IWI- ), 222, and 210.

6-(4-Decykn 9phenyl)-8-fluoro-24w-xylquinoline 12 To a degassed solution (under N2) of 6-(4"-deryloxyphenylyg-fluoro. quinoline 11. (1.00 g, 2.64 mmol) 11 in dry THIF (20 ml) at -40 C'was added dropwise with stirring 2M nhexyllithium (1.3 ml,"2.6 mmol). The mixture was allowed to" warm to ambient temperature and then heated at 50 IOC for lh. Water was added and the product was extracted into ether (2 x)- The extracts were washed with water, dried and evaporated- Recrystallisation from. EtOR gave the pure 8-fluoroquinoline 12 (0-71 g- 58%); transitionsM C 49.2 SmA 92.4 1, v,., 2950, 2920s,, 2870w, 2840, 1600, 1510, 1485, 1410, 1280, 1250, 1200, 1180, 1100, 1015, and 830 cni4; &.. 0.89 (6 1-, t, Me), 1.24-1.55 (20 R M CH2), 1.82 (4 IL quint, OCH2CHz and CCH2CHz), 3-02 (2 K t, J 7.5, CCHz), 4.02 (2 YL t, J 6-5, OCH2), 7.01 (2 K d, J 8, 3 -- and 5'-H), 7-36 (1 FL J 183,3-M, 7.61 (2 K d, J 8, 2'- and 6'-11), 7.64. (1 IL dd, J.13 and 2, 7-14), 7.70 (1 K d J 2, 5-M2 and 8.09 (IR dd, J 9 and 2, 4-H); Wz 463 (M); 448, 434, 420, 406, 393(100'/6), 279,and253.

2,6-Bis-(2'.3'Afluoro-4'-octylaxyphenyl)quinoline 14 Quantities: 2,"ibromoquinoline' 13 (1.48 g, 5.16 mmol), 2,3-difluoro4octyloxyphemiy1boronic acid (3.24 g, 11.3 mmol), teftaWtriphenylphospbine)paUadium(O) (299 mg, 0-26 nunot), 1,2ditnetho)Wethane (40 n:d), 2M aqueous sodium carbonate (40 nil). The experunental procedure was as described for 6-(4'-<)ctyloxyphenyl)-2methylqu'moline 4a. Flash chromatograpky (10 to 20/9 EtOAc-Ught pettoleum) gave the vale yellow 2,6&ivylquinoftne 14 (1.50 g, 67%) (from EtOH/EtOAc); transitions/C C 136.2 Sn3C 178.7 SmA 189.6 1; v..,-.2950, 2930, 2920, 2970, 2850, 1630, -1520, 1470s, 1340, 1310, 1195, 1095, 1070, and 800 cni4; 8--- 0.94 (6 TT, t, Me), 1.20-1.60 (20 T-T, m, CT-T2), 1.86 (4 K quint OC-H2CH2), 4.10 (2 J 7, OCH2), 4.13 (2 K t, J 7, OCHZ), 6.86 (1 IL Add), 6-92 (1 ddd), 7.21 (1 K dd, J 9 and 2, 3-M, 7-88 (3 IL m), 7.97 (1 K br s,, 5-H), 8.18 (1 K d, J 9, 4or &-M and 9-23 (1 K d J 9, 4- or 8-M; m/z 609 (M), 3 95, 365, 337, 309, 266, and 253 - References Welter, J Prakt. Chemie-, 1891, 43, 497.

16 Compounds 5b, 5c, 5f and 14 are examples according to the first aspect of the invention in which R, is substituted with one or two fluorine atoms; compounds 8 and 14 are examples according to the f irst aspect of the invention in which R, is substituted with one or two fluorine atoms; and compound 12 is an example according to the f irst aspect of the invention in which the quinoline nucleus is substituted with a fluorine atom.

Compounds 5a to 5f, 12 and 14 are examples according to the second or third aspects of the invention.

A further compound of the formula (7):

C5H, 1 N OC8H17 has been prepared, and is an example of a compound according to the first aspect of the invention in which a fluorine atom is substituted on the quinolin6 nucleus at the 8- position and R, is connected to the quinoline nucleus by an ethynyl group. The compound has high dielectric biaxiality and a relatively low melting point. Phase transitions are determined to be (in OC):- 1 91.1 N 54.1 SmC 56.1 C (melting point). 25 If desired, the unsaturated linkage of the compound (7) can be reduced in known manner, f or example using hydrogen with a Pd/Pt catalyst, to provide the 6-heptyl compound.

17 As will be seen from the foregoing description, compounds according to the invention frequently possess one or more liquid crystal phases extending over a reasonably large temperature range. They are useful, either per se or in admixture with other liquid crystal materials, in liquid crystal devices, for example optical modulators and displays. In electrically controlled devices, the negative dielectric anisotropy exhibited by certain of the compounds will be found advantageous.

18

Claims

1. A 2,6-quinoline derivative comprising a group R,-Aat the 6-position and a group R,-B- at the 2-position, wherein R. and R, may be the same or dif f erent and are each selected from an alkyl or alkoxy group, which may or may not comprise further substituents, may be saturated or unsaturated, branched or straight chain; an aryl group substituted with an alkoxy or alkyl group, wherein either of the aryl and alkyl/alkoxy groups may or may not comprise further substituents, and the alkyl or -alkoxy group may be saturated or unsaturated, branched or straight chain; a nitrile group; and a trifluoromethyl group; wherein at least one said alkyl or alkoxy group is present; wherein A and B may be the same or dif f erent., and are each selected from a direct bond, or a linking group providing a linking chain length of up to four atoms between the quinoline nucleus and the respective substituent Ri or R,; wherein, excluding any terminal hydrogen atom, the, or at least one, said alkyl or alkoxy group (a) provides a maximum chain length of no less than four atoms and no more than 16 atoms if joined directly to the quinoline nucleus, or if substituted on a said aryl group; or (b) if joined to the quinoline nucleus by a said linking group A or B, provides with the said joining group a chain length of at least 4 atoms and no more than 16 atoms extending from the quinoline nucleus; and wherein at least one of the quinoline nucleus, the R,.-Acombination and the P-2-B- combination includes a fluorine substituent'. -- 19

2. A quinoline derivative according to claim I wherein the quinoline nucleus comprises at least one fluorine atom, on the 3, 4, 5, 7 or 8position.

3. A quinoline derivative according to claim 2 wherein the fluorine atom is at the 8-position.

4. A quinoline derivative according to any preceding claim wherein at least one 'of R, and R, comprises an aryl group substituted with at least one fluorine atom.

5. A quinoline derivative according to claim 6 wherein said aryl group includes two fluorine atoms.

6. A quinoline derivative according to any one of claims 1 to 3 wherein at least one of RI and R, is a benzene ring substituted with said alkyl or alkoxy group.

7. A quinoline derivative according to claim 6 wherein said benzene ring is substituted by said alkyl or alkoxy group in the para-position.

8. A quinoline derivative according to claim 6 or claim 7 wherein said benzene ring includes a fluorine substituent.

9. A quinoline derivative according to claim 8 wherein said benzene ring includes two fluorine substituents on adjacent carbon atoms.

10. A quinoline derivative according to any preceding claim wherein A is a direct bond.

11. A quinoline derivative according to any one of claims I to 9 wherein A and/or B provides a said linking chain length of two atoms.

12. A quinoline derivative according to claim 11 wherein A is ethynyl.

13. A quinoline derivative according to any preceding claim wherein B is a dir'ect bond.

14. A quinoline derivative according to any preceding claim wherein, excluding any terminal hydrogen atom, each of Rl and R., is or comprises a respective said alkyl or alkoxy group which (a) provides a maximum chain length of no less than four atoms and no more than 16 atoms if joined directly to the quinoline nucleus, or if substituted on a said aryl group; or (b) if joined to the quinoline nucleus by a said linking group A or B, provides with the said joining group a maximum chain length of at least 4 atoms and no more than 16 atoms extending from the quinoline nucleus.

15. A 2,6-quinoline derivative comprising a group R,-Aat the 6-position and a group R,-B- at the 2-position, wherein R, and R, may be the same or dif f erent and are each selected from an alkyl or alkoxy group, which may or may not comprise further substituents, may be saturated or unsaturated, branched or straight chain; a nitrile group; and a trifluoromethyl group; wherein at least one said a-lkyl or alkoxy group is present; wherein A is an aryl group; wherein B is selected from a direct bond and a linking group providing a chain of up to four atoms between the quinoline nucleus and the respective substituent R,; wherein, excluding any terminal hydrogen atom, the maximum chain length of the group R., and/or the maximum 21 chain length of the group R.-B- is no less than 4 atoms and no more than 16 atoms.

16. A quinoline derivative according to claim 14 wherein 5 B is a direct bond.

17. A quinoline derivative according to claim 15 or claim 16 wherein, excluding any terminal hydrogen atom, R, is a said alkyl or alkoxy group which provides a maximum chain length of no less than f our atoms and no more than 16 and R, provides with the said joining group B a maximum chain length of at least 4 atoms and no more than 16 atoms.

18. A 2,6-quinoline derivative comprising a group R,-Aat the 6-position and a group R,-B- at the 2-position, wherein R land R, may be the same or dif f erent and are each selected f rom an alkyl or alkoxy group, which may or may not comprise further substituents, may be saturated or unsaturated, branched or straight chain; a nitrile group; and a trifluoromethyl group; wherein at least one said alkyl or alkoxy group is present; 25 wherein A and B are aryl groups which may be the same or different; and wherein, excluding any terminal hydrogen atom, the maX3_MUM Chain length of the group R, and/or the maximum chain length of the group R,-B- is no less than 4 atoms and no more than 16 atoms.

19. A quinoline derivative according to claim 18 wherein B is a benzene ring.

20. A quinoline derivative according to claim IS or claim 19 wherein B comprises at least one fluorine substituent.

22

21. A quinoline derivative according to one of claims 18 to 20 wherein each of R, and R, is a respective said alkyl or alkoxy group which, excluding any terminal hydrogen atom, provides a maximum chain length of no less than four atoms and no more than 16 atoms.

22. A quinoline derivative according to any one of claims 15 to 21 wherein R. comprises a said alkoxy group 10 and R, comprises a said alkyl group.

23. A quinoline derivative according to any one of claims 15 to 21 wherein R, and R, both comprise said alkoxy groups.

24. A quinoline derivative according to any one of claims 15 to 23 wherein A comprises at least one fluorine substituent.

25. A quinoline derivative according to any one of claims 15 to 24 wherein A is a benzene ring.

26. A quinoline derivative according to any one of claims 15 to 25 wherein the quinoline nucleus comprises 25 at least one fluorine substituent.

27. A quinoline derivative according to any preceding claim wherein the molecule contains a chiral centre.

28. A 2,6-quinoline derivative as claimed in any one of claims 1, 15 and 18 and substantially as hereinbefore described.

29. A method of preparing a 2,6-quinoline derivative according to any preceding claim, the method being substantially as hereinbefore described.

23

30. A method of preparing a 2,6-quinoline compound according to claim I wherein the ethynyl linkage of a compound according to claim 12 is reduced to a saturated linkage.

31. A liquid crystal material or composition comprising a 2,6-quinoline derivative according to any one of claims I to 28.

32. A light modulator comprising a 2,6-quinoline derivative according to any one of claims 1 to 28.

33. An electro-optic device comprising a 2,6-quinoline derivative according to any one of claims I to 28.

24