The title compound, C(14)H(18)N(2)O(4)S, contains hydrogen-bonded dimeric pairs of mol-ecules arranged around inversion centers, forming 14-membered rings with an R(2) (2)(14) motif. The structure is stabilized by extensive intra-molecular inter-actions. The thia-zine ring adopts a half-chair conformation, with the S and N atoms displaced by -0.485 (3) and 0.296 (3) Å, respectively, from the plane formed by the remaining atoms of the ring.