title: Detailed study of oxidative esterification and elimination reactions undergone by a steroidal 17 alpha-benzoyloxy-20-oxo-21-aldehyde.
abstract: The reaction of 17 alpha-benzoyloxy-11 beta-hydroxy-3,20-dioxo-1, 4-pregnadien-21-al as the hemiacetal (1) with methanol:acetic acid:potassium cyanide:manganese dioxide followed by acetylation and preparative HPLC of the reaction mixture afforded 11 crystalline products. These products can be conveniently divided into three categories representing side-chain cleavage and oxidative esterification with or without elimination of the benzoyloxy group. Of special interest was the stereospecific formation of the C-17 cyanohydrin acetate 4a and the cis delta 17(20) enol acetate methyl ester 5. On the other hand, nonstereospecific addition of HCN to the side chain gave the C-20 epimeric cyanohydrin acetates 7a and 7b. The use of activated versus nonactivated MnO2 plays a major role in determining the quantitative distribution of the products. It was also discovered that even in the absence of MnO2, the reaction goes to completion. A proposed mechanism which explains the formation of all products is presented.
authors.affiliation: Department of Medicine, Crozer-Chester Medical Center, PA 19013.
authors.forename: M L
authors.initials: ML
authors.lastname: Lewbart
authors.forename: R S
authors.initials: RS
authors.lastname: Annan
authors.forename: B H
authors.initials: BH
authors.lastname: Arison
authors.forename: J P
authors.initials: JP
authors.lastname: Springer
authors.forename: S R
authors.initials: SR
authors.lastname: Gould
mesh_terms: D055598:Chemical Phenomena; D002621:Chemistry; D004951:Esterification; D011245:Pregnadienes
chemical_list: D011245:Pregnadienes; C064462:17-benzoyloxy-11-hydroxy-3,20-dioxo-1,4-pregnadien-21-al hemiacetal