SYNTHESIS AND REACTIVITY OF BICYCLOMYCIN C(3') AMINES

The novel bicyclomycin C(3') tertiary amines 6-8 were prepared in which morpholine, N-acetylpiperazine, and N-carboethoxypiperazine were installed at the C(3') site in bicyclomycin (1), respectively. Previous attempts to synthesize bicyclomycin C(3') amines were unsuccessful. Compounds 6-8 were found to be more reactive than 1 in neutral and basic solutions. Under these conditions, a novel ring fragmentation process occurred to give a monosubstituted hydantoin (i.e., 15, 18, 19) and alpha-methylene-gamma-butyrolactone (17). Pathways for the formation of hydantoins 15, 18, and 19 and butyrolactone 17 are proposed, and evidence is presented in support of these hypotheses. The potential significance of this ring fragmentation process in future drug design is discussed.