Abstract
A new Schiff base ester, 4-{[(4-fluorophenyl)imino]methyl}-3-hydroxyphenyl 4-(hexadecanoyloxy)benzoate was synthesized and its IR, 1H NMR, 13C NMR and EI-MS spectroscopic data are presented.
Schiff bases have attracted much attention from many researchers owing to their thermochromic and photochromic properties [1,2,3,4,5]. The presence of a long alkyl chain at the para position of the aldehyde or aniline fragment of N-benzylideneanilines has also been identified as one of the important requirements which favours the existence of liquid crystal phases [6,7,8]. Different alkyl chain length and terminal substituent can significantly influence the anisotropic properties of liquid crystals [6]. Thus, we report here another new derivative containing an hexadecanoyloxy chain, 4-{[(4-fluorophenyl)imino]methyl}-3-hydroxyphenyl 4-(hexadecanoyloxy)benzoate.
Scheme 1.
Synthesis of 4-{[(4-Fluorophenyl)imino]methyl}-3-hydroxyphenyl 4-(hexadecanoyloxy)benzoate.
Experimental
Analytical data were obtained on Perkin Elmer 2400 LS series CHNS/O analyzers. Electron impact mass spectra (EI-MS) were recorded by Hewlett Packard 5989A Mass Spectrometer operating at 70 eV ionizing energy. FT-IR data were recorded on a Perkin Elmer 2000-FTIR spectrophotometer. NMR spectra were recorded in CDCl3 on a Bruker 400 MHz Ultrashield Spectrometer.
4-(4-n-Hexadecanoyloxybenzoyloxy)-2-hydroxybenzaldehye was prepared according to method described in our previous work [9]. In a round-bottom flask, a mixture of the aldehyde (2.48 g, 5.0 mmol), 4-fluoroaniline (0.56 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 (1.56 g, 53%).
Melting point: 189–191 °C
MS (EI): m/z (rel. int. %) = 590 (1) (M+).
IR (KBr): νmax (cm−1), 2953, 2916, 2848 (C-H aliphatic), 1755 (C=O of C15H31COO- fragment), 1743 (C=O of benzoate), 1625 (C=N), 1605 (C=C aromatic), 1282 (C-O).
1H NMR (400 MHz, CDCl3): δ/ppm, 0.91 (t, 3H, J = 6.8 Hz, CH3-), 1.24–1.47 (m, 24H, CH3-(CH2)12-), 1.79 (quint, 2H, J = 7.5 Hz, -CH2-CH2COO-), 2.62 (t, 2H, J = 7.5 Hz, -CH2-COO-), 6.86 (dd, 1H, J = 2.2, 8.4 Hz, Ar-H), 6.93 (d, 1H, J = 2.2 Hz, Ar-H), 7.12–7.17 (m, 2H, Ar-H), 7.26–7.31 (m, 4H, Ar-H), 7.46 (d, 1H, J = 8.5 Hz, Ar-H), 8.25 (d, 2H, J = 8.8 Hz, Ar-H), 8.62 (s, 1H, CH=N), 13.45 (s, 1H, OH).
13C NMR (100 MHz, CDCl3): δ/ppm, 171.86 (C=O of C15H31COO-), 164.11 (C=O of benzoate), 163.27 (C=N), 162.94, 161.94, 155.64, 155.14, 144.93, 133.54, 132.17, 127.08, 122.92, 122.25, 117.62, 116.49, 113.33 and 110.95 for aromatic carbons, 34.81 (-CH2COO-), 25.28 (-CH2CH2COO-), 32.27, 30.03, 30.02, 30.00, 29.98, 29.94, 29.79, 29.68, 29.58, 29.46, 23.01 (CH3(CH2)12), 14.37 (CH3(CH2)12).
Elemental analysis: Calculated for C36H44NO5F, 73.32%, H, 7.52%, N, 2.38%; Found: C, 73.37%, H, 7.50%, N, 2.40%.
Supplementary materials
Supplementary File 1Supplementary File 2Supplementary File 3Acknowledgements
Authors would like to thank Universiti Tunku Abdul Rahman and Universitit Sains Malaysia for the financial supports via UTAR Research Fund and research facilities.
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