Synthesis of 2-[1,2-dihydropyrazol-4-yl]-1,3,4-thiadiazole derivatives as potential antimicrobial agents.

The synthesis of some 2-[1,2-dihydropyrazol-4-yl]-1,3,4-thiadiazole derivatives is performed by reacting 4-dithiocarboxylic acid hydrazides of 3-amino-1,2-dihydro-5H-pyrazol-5-one and 3-amino-1,2-dihydro-1-methyl-5H-pyrazol-5-one with carboxylic acid derivatives. The unusual behaviour of 3-amino-1,2-dihydro-1-methyl-5H-pyrazol-5-one towards acetylating agents is described. The antimicrobial activity of some 2-[1,2-dihydropyrazol-4-yl]-1,3,4-thiadiazole derivatives is tested in a preliminary screening.