(cis)-3-methyl-1,5-benzothiazepine-4-ones: potent analogs of the calcium channel blocker diltiazen

3-Methyl analogs of the calcium channel blocker diltiazem are reported. The title compounds were prepared from readily available amino thiophenols by a six step sequence which involves setting up the desired 2,3-cis-stereochemistry through decarboxylation under acidic conditions. To our knowledge, there are the most potent analogs of diltiazem reported to date.