Synthesis of some ethoxyphthalimide derivatives of pyrazoloisoxazoles and pyrazolopyrimidines and their antimicrobial and anticancer screening

Abstract

Synthesis of 4-arylidene-5-methyl-2,4-dihydro-3H-pyrazol-3-one (IIIa-d) has been achieved by the condensation reaction between 5-methyl-2,4-dihydro-3H-pyrazol-3-one (I) and 4-substituted benzaldehydes (IIa-d). Ethyl acetoacetate and hydrazine hydrate in absolute alcohol undergo cyclization reaction to give (I). 4-Arylidene-5-methyl-2,4-dihydro-3H-pyrazol-3-ones (IIIa-d) have been converted to corresponding ethoxyphthalimide derivatives (IVa-d) by treatment with phthalimidoxyethyl bromide (A). 1-N-Ethoxyphthalimido-3-methyl-4-(4-substituted benzylidene) pyrazol-5-one (IVa-d) has been reacted with hydroxylamine hydrochloride and guanidine nitrate separately to yield ethoxyphthalimide substituted pyrazolo[3,4-c]isoxazoles (Va-d) and pyrazolo[3,4-d]pyrimidines (VIa-d) respectively. All the compounds have been characterized by elemental and spectral analysis mainly IR, ¹H NMR and mass spectroscopy. Synthesized compounds have also been screened for various biological activities viz. antibacterial, antifungal, antiviral and anticancer.