Chemistry of Phosphorus Ylides: Part 46-Efficient Synthesis and Biological Evaluation of New Phosphorus, Sulfur, and Selenium Pyrazole Derivatives

1,5-Dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazole-4-carbaldehyde was allowed to react with different phosphorus, sulfur, and selenium reagents. The reaction products depend on the nature of the reagent and the condition of the reaction used. Treatment of the carbaldehyde with the active phosphacumulene ylides afforded the phosphoranylidene pyranopyrazoles. On the other hand, its reaction with the stable phosphonium ylides gave the oxaphosphetanes. Sulfidodithiaphosphetane pyrazole was generated from the reaction of Japanese reagent with the carbaldehyde. Selenido-oxaselenaphosphetane and dioxaphospholane pyrazoles were obtained from the reaction of the carbaldehyde with Woolin's reagent and phosphorus triamide, respectively. The antimicrobial screening of the synthesized compounds was also evaluated.