In the title compound, C(9)H(11)N(3)O(2)S, the thia-zine ring adopts a half-chair conformation. In the crystal structure N-H⋯N hydrogen bonds connect two mol-ecules into a centrosymmetric dimer, forming an R(2) (2)(6) ring motif. These dimers are further connected into chains by N-H⋯O and C-H⋯O hydrogen bonds.