New pyrazole derivatives of potential biological activity

Chloro-3-methyl-1-phenyl-1H-pyrazole-4-carboxaldehyde ( 1) was reacted with hydrazine hydrate and thiosemicarbazide to afford the corresp onding hydrazones 2 and thiosemicarbazones 4. The latter compounds were used to obtain the pyra zole derivatives 3, 5-7. A series of azines 8a-e were obtained by reacting 2 with aromatic aldehydes. Potassium permanganate oxidation of 1 gave the acid 9, which was transformed into the corresponding acid azide 11 then used to prepare diverse urea derivatives 13-18 via Curtius reaction .