4327-52-0

A series of 1, 5-benzothiazepines were synthesized using disulfides and α, β-unsaturated carbonyl or nitrile compounds as reaction substrates. After reductive cleavage of the S-S bond of disulfides, the resulting thiols were reacted with α,β-unsaturated carbonyl or nitrile compounds to generated seven-membered heterocyclic compounds. In the presence of ammonium thioglycolate, the Michael reaction occurred between disulfides (1) and 4-methyl-3-penten-2-one to give 2, 2, 4-trymethyl-3H-1, 5-benzothiazepine derivatives in good yields. When ethyl acrylate or acrylonitrile was used as the Michael acceptor, 90-99% of (2-amino- phenylsulfanyl)propionitriles (3) and/or 92-99% of (2-amino-phenylsulfanyl) propionic acid ethyl esters (4) were produced. Subsequently, the 1, 5-benzothiazepine compounds 5 and 6 were obtained due to the cyclization reaction. The Japan Institute of Heterocyclic Chemistry.

An inexpensive and readily available ionic liquid, tetrabutylammonium bromide in the molten state, efficiently catalyzes the conjugate addition of thiols to α,β-unsaturated nitriles, carboxylic ester, ketones and aldehydes as well as nitro olefins.