ALLYLIC ACETOXYLATION OF DELTA-5-STEROIDS - OBSERVATION OF A COMPETING PATHWAY - A C-13-NMR STUDY OF 5-BETA-BROMO STEROIDS
DSpace at IIT Bombay
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Title |
ALLYLIC ACETOXYLATION OF DELTA-5-STEROIDS - OBSERVATION OF A COMPETING PATHWAY - A C-13-NMR STUDY OF 5-BETA-BROMO STEROIDS
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Creator |
DESAI, UR
BAIG, MHA TRIVEDI, GK |
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Subject |
neighboring group participation
nuclear magnetic-resonance 2-dimensional spectroscopy oxidation |
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Description |
The allylic acetoxylation of (25R)-spirost-5-en-22-alpha-O-3-beta-yl-acetate (1) using bromine/silver acetate/pyridine/-60-degrees has been studied. Besides the expected 4-actoxy derivative 2 (72%), two products in minor amounts, viz. 5-beta, 6-alpha-dibromo-3-beta-acetoxy steroid (3, 12%) and 5-beta-bromo-3-beta,6-beta-diacetoxy steroid (4, 4%) are obtained. The isolation of products 3 and 4 indicate a competing reaction pathway, albeit in small manner. The C-13 NMR spectra of 5-beta-bromo steroids are studied. Influence of bromine on gamma-carbons, the gamma-g effect, is found to be of immense help in deducing the A/B cis-fusion as well as to highlight configurational and conformational factors.
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Publisher |
COUNCIL SCIENTIFIC INDUSTRIAL RESEARCH
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Date |
2011-07-20T12:29:45Z
2011-12-26T12:51:29Z 2011-12-27T05:36:48Z 2011-07-20T12:29:45Z 2011-12-26T12:51:29Z 2011-12-27T05:36:48Z 1991 |
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Type |
Article
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Identifier |
INDIAN JOURNAL OF CHEMISTRY SECTION B-ORGANIC CHEMISTRY INCLUDING MEDICINAL CHEMISTRY, 30(12), 1085-1088
0376-4699 http://dspace.library.iitb.ac.in/xmlui/handle/10054/5475 http://hdl.handle.net/10054/5475 |
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Language |
en
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