Synthesis, Characterization and Fluorescence study of Certain Cinnamamide Derivatives and α, β unsaturated acids

A series of Cinnamamide were prepared by condensation of appropriate malonic acid derivatives with several aldehydes in presence of condensing agent and in its absence α, β Unsaturated acids were synthesized. The synthesized compounds were characterized by elemental analysis and I.R spectra. Introduction: Varley1 was the first to have used pyridine in malonic acid-aldehyde condensations. Later , Several substituted Cinnammamides have been reported by condensing malonic derivatives such as N-phenyl malonamic acid, N-(2, 3 or 4 methyl)phenyl malonamic acids, N-(2, 3 or 4 -Cl) phenyl malonamic acids, N-(2methoxy)phenyl malonamic acids, N-(2 and 4 ethoxy)phenyl malonamic acids, N-1naphthyl, N-2naphthyl, N-(2)fluorenyl malonamic acids with aromatic aldehydes in the presence of pyridine. Various substituted N-phenyl cinnamamide possess wide spectrum of biological activity. They have been useful as anticonvulsant drugs 2-4-3, inhibitors of blood platelet aggregation5, insecticides6 and melanin inhibitors7, application of which gave a much reduced pigment deposit on the guinea pig skin after exposure to U.V radiations. In the course of the present work N-(4butyl) phenyl malonamic acid and N-(4isopropyl) phenyl malonamic acid have been condensed with several aldehydes. It has been observed that all the condensation produced the expected α, β Unsaturated acids in the absence ofcondensing agent Material and Method: All reagents and solvents were procured from Sigma Aldrich. The identity of compounds was confirmed by M.P., Elemental analysis and I.R. spectral data. Melting Points were determined in open capillaries on Electro-thermal apparatus and were uncorrected. Infrared (IR) spectra were recorded on Perkin Elmer RX-1 using KBr wafers. Elemental analysis was performed on Elementor Vario EL III at C.D.R.I., Lucknow. The analytical results of the elements were within ± 0.3 %. Preparation of Substituted Cinnamamides and α, β Unsaturated acids The general procedure adopted was to condense equimolecular quantities of malonamic acid and aldehyde in R.B flask in presence of pyridine. The mixture was then heated in an oil bath at 105o-110o C for four hours. The reaction mixture was first observed to melt to a clear solution with effervescence and afterwards it gets solidified. The solid product was extracted with a saturated solution of sodium bicarbonate and then filtered and washed with water 3-4 times. The filtrate gave no solid o acidification with Conc. HCl.The residue was purified by recrystallisation from ethanol and purity was checked by T.L.C (Methanol/Benzene). When the same procedure was carried out in absence of pyridine, then α, β Unsaturated acids were obtained. Result: The I.R spectrum on Perkin Elmer spectrophotometer of N-(4-butyl) phenyl cinnamamide reveals absorption at 3290 cm 1 (-NH stretching), 1662 cm ( CONH group), 1610 cm (-C=Cstretching for phenyl conjugation) 2956 cm, 1532 cm, 1440 cm ( aromatic characters). The I.R spectrum on Perkin Elmer spectrophotometer of Benzal N-(4-butyl) phenyl malonamic acid reveals absorption at 3285 cm (-NH stretching), 1655 cm ( CONH group), 1605 cm (-C=Cstretching for phenyl conjugation) 3300 cm. Kausik Ghosh et al, /J. Pharm. Sci. & Res. Vol.2 (8), 2010, 445-449