Abstract
A new Schiff base ester, 3-hydroxy-4-{[(4-chlorophenyl)imino]methyl}phenyl octadecanoate, was synthesized and its IR, 1H NMR, 13C NMR and MS spectroscopic data are presented.
Schiff bases have attracted overwhelming attentions from many researchers owing to their importance in exhibiting thermochromism and photochromism [1,2,3,4]. The presence of a long alkyl chain at the para position of the aldehyde or aniline fragment of N-benzylideneanilines has been regarded as one of the important elements which favours the existence of liquid crystal phases [5,6,7,8,9].
Synthesis
4-Formyl-3-hydroxyphenyl octadecanoate was previously prepared via Steglich esterification [10]. In a round-bottom flask, a mixture of the aldehyde I (1.74 g, 5.0 mmol), 4-chloroaniline (0.64 g, 5.0 mmol) and absolute ethanol (40 mL) was refluxed with stirring for 3 h. 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 (0.87 g, 34%).
Melting point: 116.1 °C
MS (EI): m/z = 514 (M+)
IR (KBr, cm−1): 3435 (O-H), 2951, 2917, 2847 (C-H aliphatic); 1759 (C=O ester); 1624 (C=N); 1605, 1471 (C=C aromatic), 1095 (C-Cl).
1H NMR (400 MHz, CDCl3): δ/ppm 0.91 (t, 3H, J = 6.9 Hz, CH3), 1.28-1.44 {m, 28H, CH3(CH2)14-}, 1.78 (quint, 2H, J = 7.3 Hz, -CH2CH2COO-), 2.58 (t, 2H, J = 7.4 Hz, -CH2COO-), 6.71 (dd, 1H, J = 2.1, 8.4 Hz, Ar-H), 6.78 (d, 1H, J = 2.1 Hz, Ar-H), 7.21 (dd, 2H, J = 2.0, 8.6 Hz, Ar-H), 7.37 (dd, 2H, J = 2.3, 8.3 Hz, Ar-H), 7.39 (d, 1H, J = 8.4 Hz, Ar-H), 8.58 (s, 1H, CH=N), 13.31 (s, 1H, OH).
13C NMR (100 MHz, CDCl3): δ/ppm 171.8 (COO), 162.9 (CH=N), 162.4, 155.3, 147.3, 133.6, 133.0, 129.9, 122.7, 117.3, 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, 29.4, 23.0 (CH3(CH2)14-), 14.4 (CH3).
Elemental analysis: Calculated for C31H44ClNO3 C, 72.42%, H, 8.63%, N, 2.72%; Found: C, 72.30%, H, 8.71%, N, 2.75%.
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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