Regioselective reduction of 3-substituted 2,3-dihydrobenzothiadiazines with borohydrides

A simple and efficient synthetic path for N-1 or N-2 alkyl-substituted 2-aminobenzensulfonamides was developed based on regioselective reduction with NaBH3CN in different solvents. This simple method could be adapted for the synthesis of more advanced intermediates.