An efficient and practical synthesis of 1,3,5-trisubstituted 2-pyrazoline structures was achieved through cyclization of phenylhydrazine with α,β--unsaturated ketones (chalcones) using methanoic acid (formic acid) as catalyst under thermal condition.

Trichloroisocyanuric acid as a commercially available and inexpensive catalyst has been used in a new, facile and efficient procedure for the synthesis of 2-oxazolines, 2-imidazolines and 2-thiazolines through the reaction of nitriles with 2-aminoethanol, ethylenediamine or 2-aminoethanthiol under solvent -free conditions