Convenient syntheses of 2,3,4,5-tetrahydro-1,4-benzothiazepines, -1,4-benzoxazepines and -1,4-benzodiazepines

Abstract

4-Benzotriazolylmethyl-2,3,4,5-tetrahydro-1,4-benzothiazepines 5a,b, -1,4-benzoxazepine (12) and -1,4-benzodiazepine (20) are obtained via aluminium chloride mediated intramolecular cyclizations of N,N-bis(1H-1,2,3-benzotriazol-1-ylmethyl)-2-(arylthio)ethan-1-amines 4a,b, -2-(phenoxy)ethan-1-amine (11) and -N-[2-(N′-methylanilino)ethyl]amine (19), respectively. Subsequent nucleophilic substitutions of the benzotriazolyl group in 5a,b, 12 and 20 succeeded with Grignard reagents, triethyl phosphite, sodium borohydride, and a silyl enol ether to give novel 2,3,4,5-tetrahydro-1,4-benzothiazepines 6–9, -1,4-benzoxazepines 13 and 14, and -1,4-benzodiazepines 21–23 in good yields.