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DOI: 10.1055/s-0029-1219833
Synthesis of New Chiral Smectic Mesogenes with 4-(2-Phenylethyl)biphenyl and 4-[2-(3-Fluorophenyl)ethyl]biphenyl Molecular Cores
Publikationsverlauf
Publikationsdatum:
15. April 2010 (online)
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Abstract
Two methods of synthesis of chosen 1-[4-(1-methyl-heptyloxycarbonyl)phenyl]-2-[4′-(2,2,3,3,4,4,4-heptafluorobutoxyalkoxy)biphenyl-4-yl]ethanes and 1-[3-fluoro-4-(1-methylheptyloxycarbonyl)phenyl]-2-[4′-(2,2,3,3,4,4,4-heptafluorobutoxyalkoxy)bi-phenyl-4-yl]ethanes have been proposed, checked and compared. The compounds were prepared by Sonogashira coupling of 4-benzyloxy-4′-ethynylbiphenyl with appropriate 4-halobenzoate esters followed by parallel hydrogenation of ethynylene bridge and debenzylation of hydroxyl group. The 1-[4-(1-methylheptyloxycarbonyl)phenyl]-2-[4′-hydroxybiphenyl-4-yl]ethane and 1-[3-fluoro-4-(methoxycarbonyl)phenyl]-2-[4′-hydroxybiphenyl-4-yl]ethane thus obtained has been transformed into final products by Mitsunobu reaction with ω-(2,2,3,3,4,4,4-heptafluorobutoxy)alkan-1-ols, followed by the replacing of an ester terminal chain in the case of second method.
Key words
coupling - Mitsunobu reaction - alkynes - biaryls - self-assembly
- 1
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References and Notes
Synthesis of 4-Benzyloxy-4′-ethynylbiphenyl (3)
4-Benzyloxy-4-bromobiphenyl
(128.8 g, 0.38 mol), Et3N (57.6 g, 0.57 mol), DBU (29
g, 0.19 mol), PdCl2
(PPh3)2 (2
g, 2.85 mmol), CuI (1 g, 5.27 mmol), and THF (400 mL) have been
added in a 1 L nitrogen-filled flask. The mixture were heated(boiling)
for 5 min, and 2-methyl-3-butyn-2-ol (38.3 g, 0.456 mol) has been
dropped in slowly. After 4 h of stirring the GC-MS analysis was
performed. To complete the reaction, 25% of the initial
amount of 2-methyl-3-butyn-2-ol and 0.5g of PdCl2
(PPh3)2 were
added and stirred for additional 8 h. Then the reaction mixture
was poured onto H2O and the solid was filtered off, dried
and washed using CH2Cl2 (0.5 L). The obtained
4-[4′-(benzyloxy)biphenyl-4-yl]-2-methylbut-3-yn-2-ol
(112 g, 0.33 mol), NaH (1.1 g, 46 mmol) and dry toluene (1 L) have
been placed in a flask equipped with column and distillation head
to distill off the emerging acetone. When the distillate temperature
reached the bp of toluene, the reaction mixture was cooled down
and poured onto the H2O. The organic layer was separated
and poured through active carbon pad and dried over anhyd MgSO4.
The toluene solution was concentrated and the final product crystallized
in freezer. 4-Benzyloxy-4′-ethynyl-biphenyl (3) was obtained in 57% yield (61.5
g, 0.217 mol).
MS (EI 70eV): m/z = 284 [M+
],
193, 165, 139, 91, 65. IR (neat): 3282, 3061, 3036, 2861, 2359,
2340, 1600, 1488, 1454, 1380, 1284, 1246, 1026, 1008, 812, 738,
619. ¹H NMR (200 MHz, CDCl3): δ = 7.53
(m, 2 H, ArH), 7.51 (m, 5 H, ArH), 7.43 (m, 2 H, ArH), 7.39 (m,
2 H, ArH), 7.03 (m, 2 H, ArH), 5.10 (s, CH2), 3.11 (s,
1 H CºCH). ¹³C NMR (50 MHz, CDCl3): δ = 158.89
(1 C), 141.31 (1 C), 137.04 (1 C), 133.15 (1 C), 132.74 (2 CH),
128.84 (2 CH), 128.32 (2 CH), 128.25 (2 CH), 127.69 (1 CH), 126.70
(2 CH), 120.49 (1 C), 115.44 (2 CH), 83.87 (1 C), 77.87 (1 CH),
70.28 (1 CH2). Mp 156.7-157.2 ˚C
(dec.).
1-[( S )-4-(1-Methylheptyloxycarbonyl)phenyl]-2-[4′-(2,2,3,3,4,4,4-heptafluorobutoxyhexyloxy)biphenyl-4-yl]ethane (6.6) MS (EI 70eV): 712 [M+ ], 465, 183, 55. MS (ESI+, MeOH-H2O): 735 [M + Na+], 615. IR (neat): 2934, 2856, 1710, 1608, 1499, 1354, 1222, 1103, 810, 736 cm-¹. ¹³C NMR (50 MHz, CDCl3): δ = 166.29 (1 COO), 158.55 (1 CO), 146.94 (1 CEt), 139.63 (1 CEt), 138.69 (1 C), 133.38 (1 C), 129.67 (2 CH), 128.83 (2 CH), 128.75 (1 CCOO), 128.48 (2 CH), 127.95 (2 CH), 126.67 (2 CH), 114.74 (2 CH), 73.13 (1 COOC), 71.59 (1 CH2O), 67.88 (1 CH2O), 37.87 (1 CH2Ar), 37.12 (1 CH2Ar), 36.11 (1 CH2), 31.77 (1 CH2), 29.41 (1 CH2), 29.19 (2 CH2), 25.82 (1 CH2), 25.60 (1 CH2), 25.43 (1 CH2), 22.61 (1 CH2), 20.11 (CH3), 14.08 (CH3).
81-[( S )-3-Fluoro-4-(1-methylheptyloxycarbonyl)phenyl]-2-[4′-(2,2,3,3,4,4,4-heptafluorobutoxybutoxy)biphenyl-4-yl]ethane (12.4) MS (EI, 70eV): m/z = 702 [M+ ], 465, 183, 55. MS (ESI+, MeOH-H2O): m/z = 725 [M + Na+], 605. IR (neat): 2950, 2859, 1699, 1622, 1499, 1354, 1219, 1117, 971, 817, 734.