New Dihydro and Tetrahydro Derivatives of Desmycosin

III. The Opening of Oxirane Ring of 12, 13-Epoxydesmycosin

Abstract

Opening the oxirane ring of 12, 13-epoxydesmycosin dimethylacetal (1) by catalytic hydrogenation gave the 10, ll-dihydro-12, 13-epoxy derivative (3) as the main product. Reductive oxirane cleavage was accomplished with dissolved metal (Zn) giving the 10, 13-dihydro-13-hydroxy compound (6). Mild acid hydrolysis of 6 gave expected 10, 13-dihydro-13-hydroxydesmycosin (8), but hydrolysis of 3, under the same conditions, gave three tautomeric desepoxy products.