The preparation of a 10-membered ring macrolactone by selective ozonolysis and the role of the dihydropyran-substituent on the MCPBA-oxidation reaction profile of β-lapachone phenazines

Abstract

The benzophenazine from β-lapachone was submitted to ozonolysis under conditions that selectively furnished the corresponding rigid macrocyclic lactone 7,7-dimethyl-7,8,9,10-tetrahydro-5H-benzo[3,4]oxecino[5,6-b]quinoxaline- 5,10-dione in an yield of 52%. The effect of substituents located at the dihydropyrane moiety of the phenazines, namely C2′-OH, C2′-Br and C2′-I, in the oxidation with MCPBA, was also investigated. ©2005 Sociedade Brasileira de Química.