An expedient, one-pot, stepwise sequential approach for the regioselective synthesis of pyrazolines

An efficient approach for the synthesis of pyrazoline/pyrazole-tethered pyridinyl methanones is described via a one-pot, stepwise, sequential methodology using chalcones and pyridine-4-carbohydrazide as substrates through a Michael addition followed by cyclization. The reaction proceeds via a catalyst-, solvent-, work-up-, and column-chromatography-free method under melt conditions to provide the pyrazolines in short reaction times with high atom efficiency.