Biotransformation of two stemodane diterpenes by Mucor plumbeus

• Published in: Tetrahedron Vol. 60; no. 36; pp. 7921 - 7932
• Main Authors: Fraga, Braulio M., Guillermo, Ricardo, Hernández, Melchor G., Chamy, Marı́a C., Garbarino, Juan A.
• Format: Journal Article
• Language: English
• Published: OXFORD Elsevier Ltd 30.08.2004; Elsevier
• Subjects: 13,14-Dihydroxy-stemodane rearrangement; Chemistry; Chemistry, Organic; Diterpenes; Microbiological transformations; Mucor plumbeus; Physical Sciences; Prestemodane; Science & Technology; Stemodane; 13,14-Dihydroxy-stemodane rearrangement; Microbiological transformations; Diterpenes; Stemodane; Prestemodane; Mucor plumbeus; prestemodane; 13,14-dihydroxy-stemodane rearrangement; HYDROXYLATION; diterpenes; MAGNETIC-RESONANCE SPECTROSCOPY; microbiological transformations; NATURALLY-OCCURRING SUBSTANCES; MICROBIOLOGICAL TRANSFORMATION; APHIDICOLIN; SCLAREOL; stemodane; DERIVATIVES
• ISSN: 0040-4020; 1464-5416
• DOI: 10.1016/j.tet.2004.06.055

The microbiological transformation of 13α,17-dihydroxy-stemodane ( 2 ) by the fungus Mucor plumbeus afforded 13α,17,19-trihydroxy-stemodane ( 3 ), 3β,13α,17-trihydroxy-stemodane ( 5 ), 3-oxo-13α,17-dihydroxy-stemodane ( 7 ), 7α,13α,17,19-tetrahydroxy-stemodane ( 8 ), 3β,11α,13α,17-tetrahydroxy-stemodane ( 10 ), 3β,7α,13α,17-tetrahydroxy-stemodane ( 12 ), 3β,8β,13α,17-tetrahydroxy-stemodane ( 14 ), 2α,13α,17-trihydroxy-stemodane ( 16 ), 2α,13α,17,19-tetrahydroxy-stemodane ( 17 ), 2α,3β,13α,17-tetrahydroxy-stemodane ( 20 ) and 3β,11β,13α,17-tetrahydroxy-stemodane ( 22 ), whilst the incubation of 13α,14-dihydroxy-stemodane ( 25 ) gave 3β,13α,14-trihydroxy-stemodane ( 28 ), 2α,13α,14-trihydroxy-stemodane ( 29 ) and 13α,14,19-trihydroxy-stemodane ( 30 ). Preference for hydroxylations of ring A at C-2(α), C-3(β) and C-19 were observed in both incubations. An interesting rearrangement of 13α,14α-dihydroxy-stemodanes to 14-oxo derivatives with an unusual carbon framework has been observed under acetylation conditions. We have named this skeleton prestemodane, which, as a hydrocarbon ion, had been postulated as a biogenetic precursor of stemodane. The microbiological transformation of 13α,17-dihydroxy-stemodane and 13α,14α-dihydroxy stemodane diterpenes by Mucor plumbeus preferentially lead to metabolites hydroxylated at C-2 (α), C-3(β) and C-19. An interesting rearrangement of the second group of diterpenes to compounds with a prestemodane skeleton has been observed under acetylation conditions.