6,7-Dihydroxy-6,7-dihydrocanrenone isomers: improved synthesis and proton NMR study.
The synthesis in improved yields of one 6,7-epoxide and three 6,7-dihydroxycanrenone derivatives is described. Canrenone was the starting material for all derivatives and was obtained by acid-catalyzed lactonization of potassium canrenoate. The epoxidation of canrenone to 6 alpha, 7 alpha-epoxycanrenone by m-chloroperbenzoic acid was improved by addition of a free radical inhibitor. This epoxide was efficiently cleaved to 6 beta, 7 alpha-dihydroxy-6,7-dihydrocanrenone by perchloric acid in a dioxane-water mixture; 6 beta, 7 beta- and 6 alpha, 7 alpha-dihydrocanrenone were obtained by OsO4 oxidation of canrenone in either-pyridine and subsequent reduction of the osmates by hydrogen sulfide. The stereochemistry of the products obtained from the reaction of osmium tetroxide with the 6,7-double bond of steroidal 4,6-dien-3-ones has been a controversial issue for some time. A detailed proton-NMR study of the three diol derivatives unequivocally confirmed the proposed stereochemical structure.
Tal
D M
DM
Biochemistry Department, Weizmann Institute of Science, Rehovot, Israel.
D055598:Chemical Phenomena; D002621:Chemistry; D007536:Isomerism; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D013148:Spironolactone / Q000031:analogs & derivatives*
C061691:6,7-epoxycanrenone; D013148:Spironolactone; C055913:dihydroxy-6,7-dihydrocanrenone