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An operationally simple and high yielding protocol for the synthesis of polyfunctional pyrazoles has been developed through one-pot, three-component coupling of aldehydes, 1,3-dicarbonyls, and diazo compounds as well as tosyl hydrazones. The reaction proceeds through a tandem Knoevenagel condensation, 1,3-dipolar cycloaddition, and transition metal-free oxidative aromatization reaction sequence utilizing molecular oxygen as a green oxidant. The scope of the reaction was studied by varying the aldehyde, 1,3-dicarbonyl, and diazo component individually.

An efficient metal-free one-pot protocol has been developed for the construction of 1,3,4-oxadiazole derivatives via iodine-mediated oxidative amination of benzylic C–H bonds of azaarenes.

A facile and efficient metal-free, one-pot, three component synthetic protocol has been developed for the synthesis of medicinally important substituted imidazo[1,2-a]pyridines via the iodine-catalysed oxidative amination of benzylic C-H bonds of azaarenes with 2-aminoazines and condensation with isocyanides. The presented methodology offers the advantages of wide substrate scope, moderate reaction conditions, environment friendliness, clean and simple protocol with high atom economy apart from higher yields. The synthesized compounds were screened for their anti-cancer activity in selected human cancer cell lines. Compounds 4a, 4b, 4c, 4i, 7a, 7b and 7m have significant IC values ranging from 4.88 ± 0.28 to 14.55 ± 0.74 μM.

A novel strategy for the synthesis of imidazo[1,2-a]pyridines via efficient catalyst/metal-free annulations of α-keto vinyl azides and 2-aminopyridines is described. Several imidazo[1,2-a]pyridines were synthesized from readily available vinyl azides and 2-aminopyridines and obtained in highly pure form by simply evaporating the reaction solvent. This remarkably high yielding and atom economical protocol allows the formation of three new C-N bonds through cascade reactions and rearrangements.

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A series of 2-anilinopyridyl linked benzothiazole-hydrazone conjugates (5a-aa) were designed, synthesized and evaluated for their anticancer potential.