title: Novel microbial hydroxylation of 13-ethyl-17 beta-hydroxy-18,19-dinor-17 alpha-pregn-4-en-20-yn-3-one.
abstract: The microbial transformation of the dl and the d-enantiomer of 13-ethyl-17 beta-hydroxy-18,19-dinor-17 alpha-pregn-4-en-20-yn-3-one (1) were investigated. Poor yields and poor resolutions were usually obtained for the hydroxylation reactions. Transformation of 1 by Cunninghamella blakesleeana gave 6 beta-, 7 beta-, 10 beta-, 15 alpha-hydroxy derivatives 4, 5, 6, 7, and 6 beta,10 beta-dihydroxy derivative 8; transformation of 1 by Cunninghamella echinulata afforded 5, 6, and 8. Biotransformation of dl-1 by Cunninghamella species usually gave 10 beta-hydroxy product with the low enanitomeric excess or as the racemic form. However, C. echinulata was able to efficiently differentiate the two enantiomers of 1 in the course of 6 beta,10 beta-dihydroxylation reactions. The d-enantiomer of the dl-1 was the better substrate for this type hydroxylation. The 7 beta and 15 alpha-hydroxylations of 1 by microbial cultures was unusual for 19-nor type steroids, and these hydroxylation reactions were presumably due to the presence of 17 alpha-ethynyl group.
authors.affiliation: Institute of Materia Medica, Chinese Academy of Medical Sciences, Beijing, Peoples' Republic of China.
authors.forename: S H
authors.initials: SH
authors.lastname: Hu
authors.forename: X F
authors.initials: XF
authors.lastname: Tian
authors.forename: G D
authors.initials: GD
authors.lastname: Han
mesh_terms: D001234:Aspergillus niger / Q000378:metabolism*; D001711:Biotransformation; D006900:Hydroxylation; D009682:Magnetic Resonance Spectroscopy; D009090:Mucorales / Q000378:metabolism*; D009652:Norpregnenes / Q000737:chemistry / Q000378:metabolism*; D011372:Progestins / Q000378:metabolism; D013237:Stereoisomerism
chemical_list: D009652:Norpregnenes; D011372:Progestins; C103408:norbolethone