Synthesis of 2-Alkyl(aryl)-3-methylthio-6-methyl-6-arylpyrano-[4, 3-c] pyrazol-4(2H)-ones

The synthesis of 2-alkyl(aryl)-3-methylthiopyrano[4,3-c]pyrazol-4(2H)-ones via 5, 6- dihydro-2H-pyran-2, 4-dione-3-dithioacetals with (un)substituted hydrazines is described and the mechanism of the formation of title compounds is discussed. Their structures were confirmed by 1HNMR spectra and elemental analysis.