Sydnones as Masked Hydrazines for the Synthesis of 4‐Arylazo‐1,2‐dihydro‐pyrazol‐3‐one Derivatives
摘要:
A simple and convenient one-pot synthesis of 4-(4-chlorophenylazo)-5-methyl-2-aryl- 1,2-dihydro-pyrazol -3-ones (4a-j) has been carried out from 3-arylsydnones (3a-j) by reaction with 2-(4-chlorophenyl)-hydrazono-3-oxo-butyric acid ethyl ester (2b). The 3-arylsydnones are used as masked hydrazines in this reaction. Similarly, the 4-arylazo-2-(7-hydroxy-4-methyl-2-oxo-2H-chromen-8-ylmethyl)-5-methy 1- 1,2-dihydro-pyrazol-3-ones (7a-j) were synthesized from 3+7-acetoxy-4-methyl-8-methylene)coumaryl]sydnone (5). All the newly synthesized compounds exhibited antimicrobial activity greater than the reference drugs used.