Synthesis of pyrazole-3-carboxylic acid progressed via two different protocols, one of which
is solid state. Pyrazole-3-carboxylic acid was converted into different derivatives such as ester, urea,
amide and nitrile. The amide compound was converted to nitrile using SOCl2 and DMF. Solid state
heating of carboxylic acid gave decarboxylated product. Cyclization of tetra-substituted pyrazole with
hydrazines resulted in pyrazolopyridazinones. The antimicrobial activities of the synthesized pyrazole
derivatives against Bacillus cereus, Escherichia coli, Micrococcus luteus, Staphylococcus aureus, and
Saccharomyces cerevisiae were evaluated. One of the pyrazole derivatives which possess nitro group
showed antimicrobial activity in only B. cereus, a Gram-positive bacteria, with an MIC of 128 μg/mL.