Design & Synthesis of InCl3 Catalyzed Novel Pyrazole Conjugates with 2°-Amines; Discover Their in Vitro Antimicrobial & DFT Studies

Abstract

A mild and efficient protocol was developed for the synthesis of pyrazole and 2°-amine hybrid conjugates through an InCl3 Ugi four-component reaction followed by a base mediated secondary amine coupling reaction. MCRs have been used extensively in the field of combinatorial chemistry, which offers the synthesis of libraries of similar molecules in a parallel fashion. A small library of novel N-allyl-N-(1-(4-(aminomethyl) phenyl)-2-(tert-butylamino)-2-oxoethyl)-1,3-diphenyl-1H-pyrazole-4-carboxamide scaffold was designed and synthesized through a one-pot four-component Ugi reaction, the resulting Ugi product pyrazole derivative coupled with various secondary amines to prepare target pyrazole – amine conjugate molecules. The structures of synthesized conjugates confirmed by spectroscopic techniques (NMR, C, H, N analysis, and MS). The in vitro antimicrobial survey of these pyrazole-secondary amine conjugates was supported by DFT studies; thereby notifies the conjugates are promising antimicrobial agents and are comparable to the standard antimicrobial molecules such as ampicilin, griseofulvin, isoniazide and rifampicin.