5-Chloro-3-methyl-1-phenyl-4-pyrazolecarboxaldehyde

5-Chloro-3-methyl-1-phenyl-4-pyrazolecarboxaldehyde (5-Chloro-3-methyl-1-phenyl-1H-pyrazole-4-carboxaldehyde) can be synthesized from 3-methyl-1-phenyl-1Hpyrazol-5(4H)-one under Vilsmeier-Haack reaction conditions. Knoevenagel condensation of 5-chloro-3-methyl-1-phenyl-1H-pyrazole-4-carboxaldehyde with ethylcyanoacetate at 0°C has been reported to afford ethyl-2-cyano-3-(5-chloro-3-methyl-1-phenyl-1H-pyrazole-4-yl)propionate. It participates in the synthesis of 2-((5-phenoxy-3-methyl-1-phenyl-1H-pyrazol- 4-yl)methylene)hydrazinecarbothiomide derivatives with a potential anticonvulsant property.

5-Chloro-3-methyl-1-phenyl-4-pyrazolecarboxaldehyde (5-Chloro-3-methyl-1-phenyl-1H-pyrazole-4-carboxaldehyde) may be employed as starting material for the following syntheses:

• 5-chloro-3-methyl-1-phenyl-1H-pyrazole-4-carboxaldehyde hydrazone
• N¹-((5-chloro-3-methyl-1-phenyl-1H-pyrazol-4-yl)methylene)thiosemicarbazone
• pyrazole derivatives, which were pharmacologically evaluated for analgesic (tail flick) and anti-inflammatory (based on carrageenan-induced paw edema) activities
• N′-[(5-chloro-3-methyl-1-phenyl-1H-pyrazol-4- yl)methylene] 2/4-substituted hydrazides