Reaction of 2-Phenyl-4-arylidene-1,3-oxazolones with Different Nucleophiles for Synthesis of Some New Heterocycles

Abstract

Refluxing of 1,3-oxazolone (1a) with malononitrile in dry benzene and in the presence of ammonium acetate afforded imidazolone derivative (2). However, carrying out the same reaction in absolute ethanol and in the presence of piperidine as a base gave the benzamide derivative (4). Fusion of (1a) with p-anisidine gave the open adduct benzamide (6), which cyclized in acidic medium to give imidazolone derivative (7). Heating of imidazolone (7) with malononitrile above its melting point afforded 1,3-diazepine derivative (8). Reaction of the carbohydrazide (9) with isatin in ethanol gives the corresponding Schiff base (11), which then reacted with acetyl acetone, ethyl acetoacetate, ethyl cyanoacetate, and malononitrile in n-butanol and piperidine to afford benzamide derivative (13, 14, 15) and (16), respectively. The structures of the newly synthesized compounds were established on the basis of IR, 1 H-NMR, mass spectra, and elemental analyses.