Synthesis of Pyrazolo[3,4-c][1,2]thiazin-4(3H)-one 2,2-Dioxides, New Heterocycles
The reaction of substituted ethyl 5-aminopyrazole-4-carboxylatcs with two equivalents of methanesulfonyl chloride gave the substituted ethyl 5-[bis(methylsufonyl)amino]-1H-pyrazole-4-carboxylates II. Removal of one of the methanesulfonyl groups, followed