3-Aminoacetylthiazolidine-4-carboxylate Esters and their 1-Thia-4-azaspiro[4.5]decane-3-carboxylate Derivatives. Synthesis and Stereochemical Properties

Article abstract of DOI:10.1002/jhet.5570340607

Dimethyl thiazolidine-2,4-dicarboxylate 2 and ethyl 1-thia-4-azaspiro[4.5]decane-3-carboxylates 3-5 were obtained as a diastereoisomeric mixture while their 3-aminoacetyl derivatives were isolated in only one isomeric form. These reactions of N-acylation were stereoselective, which can be explained by an interconversion of the diastereoisomers via a seco intermediate. The ¹H nmr analysis of amides 6 and 11 exhibited the presence of both cis and irons amide bond conformations, whereas only one cis conformation was observed for spiro amides 8-10 and 13-15.