Materiais moleculares funcionais contendo n-heterociclos - capes

Hockey stick-shaped LC compounds 389NMR (CDCl 3 ) d: 8.09–8.04 (m, 4H), 7.62 (d, 2H,J58.8 Hz), 7.44 (d, 2H, J58.8 Hz), 7.01 (d, 2H,J59.2 Hz), 6.87 (d, 2H, J58.8 Hz), 4.03 (m, 2H), 3.28(t, J55.2 Hz), 2.59 (t, J55.2 Hz), 2.37 (m, 2H),1.27 (broad, 28H), 0.88 (m, 6H). 13 C NMR (CDCl 3 ,ppm) d: 165.32, 164.47, 162.71, 151.86, 133.52, 132.49,129.37, 127.97, 127.31, 123.49, 116.76, 115.55, 113.02,112.17, 93.98, 88.02, 68.98, 59.47, 53.53, 48.73, 32.56,30.25, 29.99, 29.81, 28.26, 27.53, 26.68, 23.34, 14.77.Elemental analysis for C 46 H 62 N 4 O 2 : calcd C 78.59, H8.89, N 7.97; found C 78.55, H 9.18, N 7.95%.4.3.8. 2-(4-Decyloxyphenyl)-5-(4-ethynylphenyl)-1,3,4-oxadiazole, 17. (a) Coupling with 2-methyl-3-butyn-2-ol.A mixture of compound 9 (2.63 g, 5.76 mmol),PdCl 2 (PPh 3 ) 2 (42.0 mg, 0.06 mmol), CuI (5.7 mg,0.03 mmol) and TPP (15.7 mg, 0.06 mmol) in TEA(50 ml) was kept at 60uC for 40 min. Pure 2-methyl-3-butyn-2-ol (0.95 ml, 8.64 mmol) was added and themixture stirred under reflux for 4 h. After cooling, themixture was filtered through a celite pad washing withTHF (150 ml). The solvents were evaporated to give ayellow powder; yield 2.21 g (84%), m.p. 126.7uC. IR(KBr) n max /cm 21 : 3369, 2923, 2852, 1612, 1495, 1258,1170, 843. (b) Protective group elimination as acetone.The intermediate alkynol (2 g, 4.35 mmol) was dissolvedin 40 ml of toluene. NaOH (0.5 g) was added and themixture was slowly heated and acetone distilled off over4 h. Toluene was removed under reduced pressure andthe residue recrystallized from heptane to give 1.2 g(69%) of a pale yellow powder, m.p. 109.7uC. IR (KBr)n max /cm 21 :3273, 2956, 2918, 2850, 1610, 1496, 1478,1260, 1177, 841. 1 H NMR (CDCl 3 ) d: 8.06 (m, 4 H),7.63 (d, J58.2 Hz, 2H), 7.01 (d, J58.7 Hz, 2H), 4.03 (t,2H), 3.24 (s, 1H), 1.82 (m, 2H), 1.28 (broad, 14H),0.88 (t, 3H). 13 C NMR (CDCl 3 ) d: 165.5, 164.2, 162.8,133.4, 129.4, 127.3, 126.0, 124.8, 116.6, 115.7, 83.4, 80.6,69.0, 32.6, 30.2, 30.0, 29.8, 26.7, 23.4, 14.8.4.3.9. 4-Iodophenyl 49-decyloxybenzoate, 19. 4-Decyloxy benzoic acid [20] (1.26 g, 4.55 mmol) and 4-iodophenol (1.09 g, 1.26 mmol) were suspended inCH 2 Cl 2 (25 ml) under Ar atmosphere. After additionof DCC (0.94 g, 4.55 mmol) and DMAP (0.049 g,0.45 mmol) the mixture was stirred for 24 h. Theresulting white precipitate was filtered off and washedwith CH 2 Cl 2 (100 ml). The solvent was evaporated andthe white solid recrystallized from ethanol to give 1.51 g(70%) of product, m.p. 86.9uC SmA, 87.8uC I. IR (KBr)n max /cm 21 : 2946, 2918, 2851, 1724, 1606, 1510, 1283,1265, 1206, 1169, 1053, 847, 758. 1 H NMR (CDCl 3 ) d:8.11 (d, J58.7 Hz, 2H), 7.72 (d, J58.4 Hz, 2H), 6.97 (m,4H), 4.03 (t, 2H), 1.82 (m, 2H), 1.28 (broad, 14H),0.88 (t, 3H).4.3.10. 2-[4-(49-Decyloxybiphenyl-4-yl-ethynyl)phenyl]-5-(4-decyloxyphenyl)-1,3,4-oxadiazole, 4. Aryl bromide18 (0.14 g, 0.36 mmol), PdCl 2 (PPh 3 ) 2 (25.5 mg,0.036 mmol), CuI (3.4 mg, 0.018 mmol) and TPP(10.0 mg, 0.036 mmol) in TEA (30 ml) were kept at60uC for 40 min. Compound 18 (0.146 g, 0.36 mmol),dissolved in 10 ml of THF, was then added dropwise.The reaction mixture was heated under reflux for afurther 24 h and left to cool to room temperature. Theprecipitate was filtered, washing with TEA (50 ml). Thesolid residue was purified by column chromatography(silica gel, chloroform), and twice recrystallized fromethanol affording the pure product; yield 0.122 g (47%).IR (KBr) n max /cm 21 : 2919, 2849, 1609, 1494, 1474, 1303,1258, 1175, 1013, 840.1 H NMR (CDCl 3 ) d: 8.11–8.06 (m, 6H), 7.68 (m, 4H), 7.50 (m, 2H), 7.02 (m, 4H),4.03 (m, 4H), 1.80 (m, 4H), 1.27 (broad, 28H), 0.87 (t,6H). Elemental analysis for C 48 H 58 N 2 O 3 : calcd C 81.09,H 8.22, N 3.94; found C 81.04, H 8.29, N 3.87%.4.3.11. 4-Decyloxybenzoic acid 4-{4-[5-(4-decyloxyphenyl)-1,3,4-oxadiazol-2-yl]phenylethynyl}phenylester,7. This compound was obtained by coupling betweenarylacetylene 17 and 4-iodophenyl 49-decyloxybenzoate19 using the same procedure as described for compound4; yield 61%. IR (KBr) n max /cm 21 : 2954, 2918, 2850,1724, 1609, 1497, 1252, 841. 1 H NMR (CDCl 3 ) d: 8.08(m, 6H), 7.69 – 7.60 (m, 4H), 7.25 (d, 2H, J58.8 Hz),7.01 (m, 4H), 4.05 (m, 4H), 1.81 (m, 4H), 1.28 (broad,28H), 0.88 (t, 6H). 13 C NMR (CDCl 3 , ppm) d: 165.1,164.8, 164.0, 163.9, 151.5, 133.6, 132.7, 129.1, 128.8,127.1, 123.8, 122.8, 121.9, 116.3, 116.2, 115.7, 113.9,91.8, 88.9, 68.6, 68.5, 32.1, 29.8, 29.6, 29.5, 29.3, 26.2,22.9, 14.3. Elemental analysis for C 49 H 58 N 2 O 5 : calcd C77.95, H 7.74, N 3.71; found C 77.48, H 7.56, N 3.73%.AcknowledgmentsThe authors thank Mrs Marly da Silveira Soldi (DSCmeasurements), also Prof. Edson Minatti and Fabio daSilva Miranda for free access to photophysical instruments.This work was supported by the agencies CNPq-Brazil and Funcitec/SC.References[1] S. Diele, A. Mac Dicke, E. Geiber, K. Meinel, D. Demus,H. Sackmann. Mol. Cryst. liq. Cryst., 166, 131 (1989);C.M. Paleos, D. Tsiourvias. Angew. Chem. int. Ed. Engl.,107, 1839 (1995); C. Tschierske, A. Lunow, H. Zaschze.Liq. Cryst., 8, 885 (1990); K. Praefcke, K.B. Kohne, S.Diele, G. Pelzl, A. Kjaer. Liq. Cryst., 11, 1 (1992); G.Lattermann, G. Safer. Mol. Cryst. liq. Cryst., 191, 199