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- Title
Photooxygenation of Pregnanes.
- Authors
Mara 4;A. Ponce; Rosa Erra-Balsells; Andrea 4;C. Bruttomesso; Eduardo 4;G. Gros
- Abstract
The course of the singlet-oxygen reaction with pregn-17(20)-enes and pregn-5,17(20)-dienes was studied to compare the reactivity of the two alkene moieties present in some steroid families. Thus, from commercially available (3,5a)-hydroxy-androstan-17-one and (3)-3-hydroxyandrost-5-en-17-one, the following 3-{[(tert-butyl)dimethylsilyl]oxy}-substituted, 17(20)-unsaturated pregnanes were prepared (see Fig. 4;1): (3,5a)-21-norpregn-17(20)-ene 1; (3,5a,17Z)-pregn-17(20)-ene 2, (3,5a,16a,17E)-pregn-17(20)-en-16-ol 3, (16,5a,17E)-pregn-17(20)-en-16-ol 4, (3,5a,16,17E)-pregn-17(20)-en-16-ol acetate 5, (3,16a)-21-norpregna-5,17(20)-dien-16-ol 6, (3,16a,17E)-pregna-5,17(20)-dien-16-ol 7, (3,17Z)-pregna-5,17(20)-diene 8, (3,17E)-pregna-5,17(20)-dien-21-ol 9 and (3,17E)-5,17(20)-dien-21-ol acetate 10. The oxygenated products (see Fig. 4;2) obtained from 110 and 1O2, generated by irradiation of Rose Bengal in 3O2-saturated pyridine solution, were characterized by 1H-, 13C-NMR, and MS (EI, FAB, HR-EI, ESI- and UV-MALDI-TOF) data. Major products were those formed by the ene reaction involving as intermediates the corresponding hydroperoxides and the cyclic tautomers of the allylic hydroperoxides, i.e., the corresponding oxiranium oxide-like intermediate (Scheme 4;5).
- Subjects
PHOTOSYNTHETIC oxygen evolution; PHOTOSYNTHESIS; IRRADIATION; NONMETALS
- Publication
Helvetica Chimica Acta, 2004, Vol 87, Issue 12, p2987
- ISSN
0018-019X
- Publication type
Article