Synthetic studies on bicyclomycin and its analogues. Part 1. Synthesis of substituted 2-oxa-8,10-diazabicyclo[4.2.2]decanes

Abstract

Methods have been developed for formation of the eight-membered oxygen-containing ring system (2) present in the antibiotic bicyclomycin. The procedure starts with N,N′-disubstituted piperazine-2,5-diones or the corresponding mono imino ethers. A new method is based on the oxidation of the mono imino ethers using 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) as oxidant: the bis imino ethers gave pyrazines under these conditions, whilst the parent piperazinedione proved to be unreactive.