Ringerweiterungen und Ringverengungen bei der Umsetzung von 1,3- Oxazolidin-2,4-dionen und 1,3-Thiazolidin-2,4-dion mit 3-Amino-2H-azirinen

Abstract

The reaction of 3-amino-2H-azirines 1 and 1,3-oxazolidine-2,4-diones 2 in MeCN at room temperature leads to 3,4-dihydro-3-(2-hydroxyacetyl)-2H-imidazol-2-ones 3 in good yield (Scheme 2, Table I). A reaction mechanism proceeding via ring enlargement of the bicyclic zwitterion A to give B, followed by transannular ring contraction to C, is proposed for the formation of 3. This mechanism is in accordance with the result of the reaction of 2a and the 15N-labelled 1a*: in the isolated product 3a*, only N(3) is labelled (Scheme 2). The anal Show more