cis-(±)-5-[2-(Dimethylamino)ethyl]-3-hydroxy-2-(4-methoxyphenyl)-2,3,4,5-tetrahydro-1,5-benzothiazepin-4-one

The title compound, C₂₀H₂₄N₂O₃S, is a drug intermediate of diltiazem. The molecule is stabilized by covalent bonding and weak hydrogen bonding, and the crystal packing is stabilized by hydrogen bonding. The seven-membered ring is distorted showing a twist-boat conformation. The methoxyphenyl and hydroxy groups are cis oriented with respect to one another, with the phenyl ring in an axial position. Intermolecular hydrogen bonding produces dimers in the crystal.

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