Tetrahydro‐6‐methyl‐1H,3H‐thieno[3,4‐b]pyrrol‐2‐one, an Analogue of Biotin

The title compound, C 7 H 11 NOS, an analogue of biotin, was prepared in order to further investigate the binding characteristics of biotin. The bicyclic ring system has pseudo-mirror symmetry with the tetrahydrothieno ring in an S5β-envelope form with the methyl substituent in an equatorial position. The cis-fused pyrrolidone system is planar [non-H atoms coplanar within 0.03 (1) A] and the dihedral angle between it and the four coplanar C atoms of the tetrahydrothieno ring is 119.0(2)°. The C-S bond lengths are 1.808 (4) and 1.803(4)A, and the C-S-C angle is 88.8 (2)°.