Crystal structure of ( Z )-2-benzylidene-4-methyl-2 H -benzo[ b ][1,4]thiazin-3(4 H )-one

In the title compound, C 16 H 13 NOS, the 1,4-thiazine ring displays a screw-boat conformation. The conformation about the ethene bond [1.344 (2) Å] is Z . The plane of the fused benzene ring makes a dihedral angle of 58.95 (9)° with the pendent phenyl ring, indicating a twisted conformation in the molecule. In the crystal, molecules are linked by pairs of C—H...O hydrogen bonds, forming inversion dimers.