Friday , 27 November 2020

Synthesis and Characterization of 4-(2-Chlorobenzylidene)-1-{4-[3-(substituted phenyl)prop-2-enoyl]phenyl}-2-phenyl-imidazol-5-one

About author :
Amee B. Patel & Pankaj S. Patel*
Department of Chemistry, Sheth L.H. Science College, Mansa, India.
Scholar of J.J.T. University, Jhunjhunu, Rajasthan.

Abstract :
4-(2-Chlorobenzylidene)-1-{4-[3-(substituted phenyl)prop-2-enoyl]phenyl}-2-phenyl-imidazol-5-one synthesized by the condensation of 1-(4-acetylphenyl)-4-(2-chlorobenzylidene)-2-phenyl-imidazol-5-one with various aldehydes in presence of ethanol. The intermediate 1-(4-acetylphenyl)-4-(2-chlorobenzylidene)-2-phenyl-imidazol-5-one synthesized by the condensation of  4-(2-chlorobenzylidene)-2-phenyl-1,3-oxazol-5-one  with 1-(4-aminophenyl) ethanone in presence of pyridine. The product is characterized by spectral and analytical data.
Key word: Synthesis, substituted Chalcones, substitutedphenyl, Oxoimidazoline
The chemistry of heterocycles lies at the heart of drug discovery1 Oxoimidazoline also known as imidazolines. Imidazolines have been found to be associated with several pharmacological activities.2-7 During the past decade a large number of imidazoline containing compounds have been in the market with diverse pharmacological properties e.g. ,clonidine, phentolamine for the treatment of hypertension, cimentidine as antiulcer, dacardazine as anticancer ketoconazole, econazole as antifungal agents. Encouraged by these observations, we have synthesized various new imidazol-5-one moiety and tested them for antimicrobial activity. The condensation of substituted aromatic aldehydes with acetyl glycine in presence of sodium acetate and acetic anhydride as reported in literature.
Melting points were taken in open capillary tube and were uncorrected. IR spectra (KBr) were recorded on I.R. Spectrophotometer of Buck scientific Model No. 500 and instrument used for NMR Spectroscopy was DUL 13C-1, 300 MHz and tetramethyl silane used as internal standard. Solvent used were CDCl3 and DMSO. Purity of the compounds were checked by tlc on silica- G plates. Anti microbial activities were tested by Cup-Borer method.
1. Preparation of 4-(2-chlorobenzylidene)-2-phenyl-1,3-oxazol-5-one 
 In a 500 ml conical flask equipped with a reflux condenser a mixture of 2-chlorobenzylidene (0.25M), hippuric acid (0.25 M), acetic anhydride (0.75M) and anhydrous sodium acetate (0.25 M) was placed and heated on an electric hot plate with constant shaking. As soon as the mixture has liquefied completely, transfer the flask to a water bath and heat for 2 hours. Then add 100 ml of ethanol slowly to the contents of the flask, allow the mixture to stand overnight, filter the crystalline product with solution, wash with  25 ml  of ice-cold alcohol and then finaly wash with  25 ml of boiling water, dry at 100 0C. The yield of the product was 75% and the product melts at 1600C. Found: C(67.71%) H(3.53%) N(4.90%), Calcd. for C16H10ClNO2: C(67.74%) H(3.55%) N(4.94%) 
2.Preparation of 1-(4-acetylphenyl)-4-(2-chlorobenzylidene)-2-phenyl-imidazol-5-one 
In a 250 ml conical flask equipped with a reflux condenser a mixture of 4-(2-chlorobenzylidene)-2-phenyl-1,3-oxazol-5-one (0.1M), 1-(4-aminophenyl)ethanone (0.1M), 25 ml pyridine and about one pellet of KOH was placed and was heated on sand bath for 7-8 hours. The mixture was then poured in ice. The precipitates were collected, washed with 10% HCl and re-crystallized from ethanol. The yield of the product was 72% and the product melts at 1450C. Found: C(71.90%) H(4.24%) N(6.96%), Calcd. for C24H17ClN2O2: C(71.91%) H(4.27%) N(6.99%) IR (KBr); (cm-1): 1710(>C=Oimidazolone),1650 (>C=N-), 1600(>C = C<), 1250(C-N).
3.Preparation of 4-(2-Chlorobenzylidene)-1-{4-[3-(substitutedphenyl)prop-2-enoyl]phenyl}-2-phenyl-imidazol-5-one
To the solution of 1-(4-acetylphenyl)-4-(2-chlorobenzylidene)-2-phenyl-imidazol-5-one (0.01M) in absolute ethanol (50 ml), substituted benzaldehyde (0.01M) and 2% NaOH (10 ml) were added and refluxed for 10 hours. After refluxing the reaction mixture was concentrated , cooled, filtered and neutralized with dil. HCl. The solid residue thus obtained was crystallized by absolute  ethanol. IR (KBr); AB-5 (cm-1): 3400(-OH), 3100(=C-H), 2950(-C-H), 1720(>C=O imidazolone), 1650(>C=N-), 1600(>C = C<),1200  (C-N), 600  (C-Cl). NMR ; AB-3 : d 3.490, singlate (6H)(-OCH3), d 7.631, singlate  (1H) (=CH-vinylic), d 6.660-7.902 , multiplate (18H) ( Ar-H , –CH=CH-).



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