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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. [ABSTRACT FROM AUTHOR]

Given the attractive ability of iminium ions to functionalize molecules directly at ostensibly unreactive positions, the reactivity of iminium ions, in which an α CH2 group is replaced by CO was explored. Background studies on the ability of such iminium cations to promote reactions via an iminium-catalyzed or iminium-equivalent pathway are apparently unavailable. Previously, tandem cross-coupling reactions were reported, in which an iminium ion undergoes nucleophilic 1,2-addition to give a putative three-component intermediate that abstracts a proton in situ and undergoes self-deamination followed by unprecedented DMSO/aerobic oxidation to generate α-ketoamides. However, later it was observed that iminium ions can generate valuable α-ketoamides through simple aerobic oxidation. In all reactions, iminium ions were generated in situ by reaction of 2-oxoaldehydes with secondary amines. [ABSTRACT FROM AUTHOR]