Preparation and oxidation of 3-aminothienotriazinones as a probe of the structure of thiopene analogs of benzocyclopropenone

Abstract

The lead tetraacetate oxidation of the isomeric 3-amino thienotriazinones (1) and (2) give different product mixtures in the presence of nucleophilic and dipolar traps. This eliminates the possibility of a single common intermediate such as the ring-closed form of the cyclopropenone (3a). The possibility of a rapid equilibration between several species such as (3a-3c) is also eliminated. The triazinone (1) gives only unrearranged products, while (2) gives small but reproducible amounts of products which suggest some rearrangement of (3c) to (3b).