rac-5-Diphenylacetyl-2,2,4-trimethyl-2,3,4,5-tetrahydro-1,5-benzothiazepine and rac-5-formyl-2,2,4-trimethyl-2,3,4,5-tetrahydro-1,5-benzothiazepine.

rac-5-Diphenylacetyl-2,2,4-trimethyl-2,3,4,5-tetrahydro-1,5-benzothiazepine, C(26)H(27)NOS, (I), and rac-5-formyl-2,2,4-trimethyl-2,3,4,5-tetrahydro-1,5-benzothiazepine, C(13)H(17)NOS, (II), are both characterized by a planar configuration around the heterocyclic N atom. In contrast with the chair conformation of the parent benzothiazepine, which has no substituents at the heterocyclic N atom, the seven-membered ring adopts a boat conformation in (I) and a conformation intermediate between boat and twist-boat in (II). The molecules lack a symmetry plane, indicating distortions from the perfect boat or twist-boat conformations. The supramolecular architectures are significantly different, depending in (I) on C-H...O interactions and intermolecular S...S contacts, and in (II) on a single aromatic pi-pi stacking interaction.