Abstract
A new Schiff base ester, 3-hydroxy-4-{[(4-fluorophenyl)imino]methyl}phenyl octadecanoate, was synthesized and its IR, 1H NMR, 13C NMR and MS spectroscopic data are presented.
Schiff base (CH=N) compounds have received a considerable amount of attention from many sresearchers owing to their importance in exhibiting thermochromism and photochromism [1,2,3]. Aromatic Schiff bases possessing a long alkyl chain have received overwhelming attention due to their possibility to show liquid crystallinity properties such as smectic and nematic phases [4,5,6,7].
Synthesis
4-Formyl-3-hydroxyphenyl octadecanoate was previously prepared via Steglich esterification [8]. In a round-bottom flask, a mixture of the aldehyde I (1.74 g, 5.0 mmol), 4-fluoroaniline (0.56 g, 5.0 mmol) and absolute ethanol (40 mL) was refluxed for 3 h with stirring. The reaction mixture was filtered and the solvent was removed from the filtrate by evaporation. Recrystallization from absolute ethanol gave the title compound as a yellow solid (1.84 g, 74%).
Melting point: 95.4 °C
MS (EI): m/z = 497 (M+)
IR (KBr, cm−1): 3454 (O-H), 2954, 2918, 2849 (C-H aliphatic); 1758 (C=O ester); 1624 (C=N); 1609, 1510 (C=C aromatic), 1245 (C-F).
1H NMR (400 MHz, CDCl3): δ/ppm 0.89 (t, 3H, J = 7.0 Hz, CH3), 1.28-1.45 {m, 28H, CH3(CH2)14-}, 1.74 (quint, 2H, J = 7.3 Hz, -CH2CH2COO-), 2.56 (t, 2H, J = 7.5 Hz, -CH2COO-), 6.71 (dd, 1H, J = 2.2, 8.4 Hz, Ar-H), 6.78 (d, 1H, J = 2.2 Hz, Ar-H), 7.10 (m, 2H, Ar-H), 7.25 (m, 2H, Ar-H), 7.38 (d, 1H, J = 8.4 Hz, Ar-H), 8.58 (s, 1H, CH=N), 13.39 (s, 1H, OH).
13C NMR (100 MHz, CDCl3): δ/ppm 172.1 (COO), 162.8 (CH=N), 161.9, 160.9, 155.0, 144.8, 133.5, 123.0, 117.4, 116.7, 113.3, 110.8 (aromatic carbons), 34.8 (-CH2COO-), 25.3 (-CH2CH2COO-), 32.3, 30.1, 30.0, 29.9, 29.8, 29.7, 29.6, 29.5, 23.1 (CH3(CH2)14-), 14.5 (CH3).
Elemental analysis: Calculated for C31H44FNO3 C, 74.81%, H, 8.91%, N, 2.81%; Found: C, 74.92%, H, 8.98%, N, 2.70%.
Supplementary materials
Supplementary File 1Supplementary File 2Supplementary File 3Acknowledgements
The author (S.T. Ha) would like to thank Universiti Tunku Abdul Rahman for the financial support and research facilities.
References and Notes
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