Regioselective synthesis of novel N2- and N4- substituted 7-methylpyrazolo[4,5-e][1,2,4]thiadiazines

Abstract

The new compound 7-methylpyrazolo[4,5-e][1,2,4]thiadiazin-3(2H,4H)-one 1,1-dioxide (5) was synthesized and its novel mono N2- or N 4-substituted derivatives 6 and 7 were prepared by regioselective N-alkylation of 5 with different molar ratios of NaH and alkyl halides. Based on the regioselective alkylation conditions found a facile one-pot synthesis of N2,N4-disubstituted pyrazolo[4,5-e][1,2,4] thiadiazines 8 was developed. The structures of the newly synthesized compounds were confirmed by IR, 1H-NMR, 13C-NMR and MS spectral analysis. © 2006 by MDPI.