2 H ‐Pyran‐2‐one‐3‐carbothioamide derivatives: Synthesis and reaction with hydrazine hydrate

N ‐Aryl‐4‐hydroxy‐6‐methyl‐2 H ‐pyran‐2‐one‐3‐carbothiamides and N ‐aryl‐4‐hydroxycoumarin‐3‐carbothiamides were synthesized by the reaction of arylisothiocyanates with 4‐hydroxy‐6‐methylpyran‐2‐one and 4‐hydroxycoumarin, respectively. Novel products 3‐[bis(arylamino)methylene]‐6‐methyl‐2 H ,4 H ‐pyran‐2,4‐diones and N , N ′‐diaryl‐4‐hydroxycoumarin‐3‐carboximidamides have also been obtained in the same reactions. Novel 4‐acetoacetyl‐3‐phenylamino‐4,5‐dihydro‐5 H ‐pyrazol‐5‐ones were synthesized from the reaction of N ‐aryl‐4‐hydroxy‐6‐methyl‐2 H ‐pyran‐2‐one‐3‐carbothiamides with an excess of hydrazine. The structure of all compounds was established by NMR and mass spectra. J. Heterocyclic Chem., (2009).