The carbon magnetic resonance spectra of a series of C-19 hydroxy, C-5β,6β epoxy, C-5α,6α epoxy, and C-24 ethyl steroids have been assigned. Shift parameters for the C-19 hydroxyl function are listed. The data presented has led to a reassignment of the published spectra of several C5α,6 α epoxy steroids. In addition, 13Cmr spectral data for several bicyclic enones and a Δ5(10)-3-estrone are presented.
The products of the incubation of androst-5-ene-3,17-dione @a), 3B-hydroxyandrost-5-ene-17-one (2b), and androsta-3,s-diene-17-one ( The C-6P hydroxylation of androst-4-ene-3,17-dione (la) by R. arrhizus ATCC 11 145 proceeds via the A395-enol form of the ketone (1). In an attempt to gain further insight into this enzymic process, we have studied the metabolism of androst-5-ene-3,17-dione (2a), the corresponding 3P-alcohol (2b), and the A3.5-enol analogue 3, by R. arrhizus under a variety of conditions. In addition we have incubated a series of epoxy steroids and related compounds, 4-9.
. DIAKOW. Can. J. Chem. 56,694 (1978). The steroid analogue 4,4a,5,6,7,8-hexahydro-2(3H)-naphthalenone was hydroxylated at C-8c(, C-88, and C-4a by Rl~hoprrs arrl~izus. Similar products were obtained by peracid oxidation of the corresponding en01 ethers: hydroxylation of estr-4-ene-3,17-dione by the same fungus occurred at the analogous C-6 and C-10 positions. These results are consistent with a mechanism of microbial hydroxylation involving the en01 form of the A4-3-ketone. Data from the incubations with R. arrlrizrrs of androst-4-ene-3,17-dione specifically labelled with deuterium at C-4, C-6rx, or C-68 and from those of other deuterium labelled substrates have been interpreted in terms of a mechanism of C-6B hydroxylation involving a rate-determining step before enolization of the ketone, followed by rapid enolization and oxidation of the en01 to give the 68-hydroxydJ-3-ketone. The kinetic isotope effect, k l I / k D , for the hydroxylation of androst-4-ene-3,17-dione at C-6p has been found to be 1.2 f 0
. J. Chem. 57. 1585 (1979).The products arising from the incubations of C-6a and C-6p chloro-, fluoro-, and methylsubstituted A4-3-keto steroids with the C-6b hydroxylating fungus Rllizopus arrhizus ATCC 11145 have been identified, and their formation rationalised in terms of A3s5 enolic intermediates. The incubations of C-6 chloro and methyl A3.' en01 acetates with R. arrhizus, and the oxidations by m-chloroperoxybenzoic acid of the corresponding en01 ethyl ethers have also been described. The relevance of the results so obtained to the mechanism of C-6p hydroxylation of A4-3-keto steroids by R. arrhizus is discussed.HERBERT L. HOLLAND et PETER R. P. DIAKOW. Can. J. Chem. 57, 1585 (1979).On a identifie les produits qui se forment par incubation de A4 cCto-3 stkroi'des (substituks en C-6a et C-6b par des chlore, fluor ou mCthyle) avec les champignons hydroxylant en C-6p, Rhizopus arrhizus ATCC 11 145 et l'on a rationalis6 leur formation en termes d'intermediaires Cnoliques A' s5. On dCcrit aussi les incubations des acCtates Cnoliques A3e5 substitues en C-6 par un chlore ou un mCthyle ainsi que les oxydations par l'acide m-chloroperbenzoique des Cthers Cnoliques Cthyliques correspondants. On discute de la relation entre ces risultats et le mecanisme de l'hydroxylation en C-6p des A4 &to-3 stCroldes par le R arrhizus.[Traduit par le journal]
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