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4-[(2-Hydroxy-4-pentadecyl-benzylidene)-amino]-benzoic Acid Methyl Ester

Research Centre for Synthesis and Catalysis, Department of Chemistry, University of Johannesburg, P.O. Box 524, Auckland Park 2006, Johannesburg, South Africa
The Institute for Drug Research, School of Pharmacy, The Hebrew University of Jerusalem, P.O. Box 12065, Jerusalem 91120, Israel
Research Center for Bioorganic Chemistry, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok-10330, Thailand
Author to whom correspondence should be addressed.
Molbank 2013, 2013(4), M810;
Submission received: 17 September 2013 / Accepted: 15 November 2013 / Published: 28 November 2013


A new Schiff base, 4-[(2-hydroxy-4-pentadecyl-benzylidene)-amino]-benzoic acid methyl ester was synthesized and its UV, IR, 1H-NMR, 13C-NMR and ESI-MS spectroscopic data are presented.

Graphical Abstract


Schiff bases have received a considerable amount of attention from many researchers owing to their importance in exhibiting thermochromism and photochromism [1,2,3,4]. Aromatic Schiff bases possessing long alkyl chain have received overwhelming attention due to their possibility to show mesomorphic properties such as smectic and nematic phases [5,6]. As a continuation of our previous work, we report here another new Schiff base compound, 4-[(2-hydroxy-4-pentadecyl-benzylidene)-amino]-benzoic acid methyl ester.


2-Hydroxy-4-pentadecylbenzaldehyde was prepared from cardanol (3-pentadecylphenol, contained, e.g., in Cashew nut shell liquid (CNSL)) by formylation, using a standard procedure [7]. The title compound was obtained by refluxing compound 2 with an equimolar amount of methyl-4-amino benzoate in 1,4-dioxane for 3 h. This new Schiff base was fully characterized by elemental analysis, UV, IR, MS, 1H-NMR and13C-NMR data. As shown in Scheme 1.


All reagents were analytical grade. Purchased from Fluka, or Aldrich chemical Co., Ltd, and were as received without further purification. Melting point was determined in open capillary and is uncorrected. Absorption spectrum was recorded in CHCl3 by a Hewlett Packard-8453 spectrophotometer. FT-IR spectrum was recorded on a Nicolet Fourier Transform Infrared Spectrophotometer: Impact 410 (Nicolet Instrument Technologies, Inc., Madison, WI, USA). 1H-NMR and 13C-NMR were obtained in DMSO-d6 at 500 MHz for 1H nuclei and 125 MHz for 13C nuclei (Bruker Company, Rheinstetten, Germany). All chemical shifts were reported in parts per million (ppm) using residual proton or carbon signal in deuterated solvents as internal references. Couping constants (J) are reported in Hertz (Hz). Mass spectra were recorded by electron spray ionization mass spectroscopy (ESI-MS) on a bruker daltornics microOTOF mass spectrometer. Elemental analysis (C, H and N) was performed on a Perkin Elmer 2400 analyzer. The purity of the compound was checked by TLC on silica gel and further purification was performed through column chromatography (silica gel, 60–120 mesh).
2-Hydroxy-4-pentadecylbenzaldehyde 2 (0.23 g, 0.71 mmole) in 1,4-dioxane (20 mL) and methyl-4-amino benzoate 3 (0.10 g, 0.71 mmol) was heated under reflux for 3 hours. The completion of the reaction was monitored by TLC. The reaction mixture was allowed to cool down to room temperature, and then poured onto ice cooled water with constant stirring. The precipitate was filtered, washed with water, dried and recrystallized from absolute ethanol. The resulting solid was further purified by silica column, using a gradient mixture of hexane/ethyl acetate (90:10) as an eluent to obtain 4.
Color: light yellow solid.
Yield: 0.21 g (65%).
Melting point: 212–214 °C.
λmax = 351 nm.
ESI-MS: m/z = 465.817 (M+).
IR (KBr): νmax (cm−1): 3441.68 (O-H str.), 2917.15 ((=C-H), w), 1723.44 (C=N str.).
1H-NMR (500 MHz, DMSO-d6) δ ppm: 12.68 (s, 1H, OH), 8.94 (s, 1H, CH=N), 8.01 (d, J = 7.7 Hz, 2H, Ar-H), 7.57 (d, J = 7.8 Hz, 1H, Ar-H), 7.48 (d, J = 7.8 Hz, 2H, Ar-H), 6.82 (d, J = 7.7 Hz, 1H, Ar-H), 6.79 (s, 1H, Ar-H), 3.85 (s, 3H, OCH3), 2.60 (t, J = 7.6 Hz, 2H, Ar-CH2), 1.56–1.13 (m, 26H, (CH2)13), 0.83 (t, J = 6.8 Hz, 3H, CH3).
13C-NMR (125 MHz, DMSO-d6) δ ppm: 163.72, 161.46, 152.44, 143.56, 132.60, 131.07, 128.22, 121.10, 120.03, 117.12, (Aromatic carbons), 52.14 (OCH3), 36.30, 31.92, 30.84, 30.63, 29.68, 29.67, 29.65, 29.55, 29.47, 29.35, 29.27, 22.68 (Methylene carbons), 14.09 (CH3).
Elemental analysis: Calculated for C30H43NO3: C, 77.38%; H, 9.31%; N, 3.01%; found: C 77.08%; H, 9.05%; N, 2.89%.

Supplementary materials

Supplementary File 1Supplementary File 2Supplementary File 3Supplementary File 4


This work was supported by the Higher Education Research Promotion and National Research University Project of Thailand, Office of the Higher Education Commission (Project No. EN1250B). The post-doctoral fellowship grant from University of Johannesburg was gratefully acknowledged.

Conflicts of Interest

The authors declare no conflict of interest.


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Scheme 1. 4-[(2-hydroxy-4-pentadecyl-benzylidene)-amino]-benzoic acid methyl ester.
Scheme 1. 4-[(2-hydroxy-4-pentadecyl-benzylidene)-amino]-benzoic acid methyl ester.
Molbank 2013 m810 sch001

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MDPI and ACS Style

Naganagowda, G.; Mahato, S.K.; Meijboom, R.; Petsom, A. 4-[(2-Hydroxy-4-pentadecyl-benzylidene)-amino]-benzoic Acid Methyl Ester. Molbank 2013, 2013, M810.

AMA Style

Naganagowda G, Mahato SK, Meijboom R, Petsom A. 4-[(2-Hydroxy-4-pentadecyl-benzylidene)-amino]-benzoic Acid Methyl Ester. Molbank. 2013; 2013(4):M810.

Chicago/Turabian Style

Naganagowda, Gadada, Sanjit Kumar Mahato, Reinout Meijboom, and Amorn Petsom. 2013. "4-[(2-Hydroxy-4-pentadecyl-benzylidene)-amino]-benzoic Acid Methyl Ester" Molbank 2013, no. 4: M810.

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