Methyl 1-allyl-4-hy­droxy-2,2-dioxo-1H-2λ⁶,1-benzo­thia­zine-3-carboxyl­ate

There are two independent mol­ecules in the asymmetric unit of the title compound, C₁₃H₁₃NO₅S, in both of which the ester substituent is nearly coplanar [C—C—C—O torsion angles = 2.7 (7) and −0.8 (7)°] with the planar fragment of the bicycle due to the formation of a strong O—H...O intra­molecular hydrogen bond. The vinyl group at the ring N atom is approximately orthogonal to the heterocyclic mean plane [C—N—C—C torsion angles = 103.1 (6) and 98.2 (5)°]. The refinement was performed on a two-component, non-merohedrally twinned crystal [population ratio = 0.483 (3):0.517 (3).