Azo bridges from azines .15. Oxygenation of unsaturated cyclic azo compounds with peracids

Azo bridges in compounds 3, 6, 11, 16, 20 and 22 are chemospecifically oxidized with MCPBA to the corresponding azoxy derivatives 4, 7, 12, 17, 21, and 23 in the presence of one or two (20, 22) double bonds even if these are located in a close parallel position to the azo bridge (6, 11, 20, 22). The order of reactivity of different olefinic moieties towards MCPBA was found to be bicycloheptene > bicyclooctene, cyclopentene. Thus, epoxy/azoxides 5, 8, 13, 14, and 19 as well as bisepoxy/azoxides 10 and 15 were obtained. If both the azo and the olefinic bridge are part of a bicycloheptane system (24) the azo group can be no longer oxidized chemospecifically (25 + 26).