Abstract
Condensation of 5-chloro-4-formyl-3-methyl-1-phenylpyrazole (1) with malononitrile in the presence of piperidine or ammonium acetate affords the corresponding pyrazole derivatives (2-4). Base-catalyzed cyclocondensation of 1 with hippuric acid or ethyl glycinate hydrochloride gives the oxazolone 6 and 5-amino-3-methyl-6-oxo-1-phenyl-1,6-dihydropyrano[2,3-c]pyrazole (7) respectively. Treatment of 1 with ethyl cyanoacetate in basic medium produce ethyl alpha-cyano-beta-(5-chloro-3-methyl-1-phenylpyrazol-4-yl)acrylate (8) which reacts with nitrogen nucleophiles to give compounds 9-12. Transesterification and/or hydrolysis of ester group has been observed on treatment of 8 with methyl alcohol in basic medium leading to the formation of acrylate derivatives (13-15), Compound 8 on treatment with ethyl acetoacetate or cyclohexanone undergoes condensation with subsequent cyclization and/or dearylation to give the adducts 16 and 17 respectively. Structures of all the products have been established by elemental analysis, IR, PMR and mass spectral data.