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Please use this identifier to cite or link to this item: http://dspace.library.iitb.ac.in/jspui/handle/10054/5205

Title: Differential behavior of (25R)-5,6-epoxyspirostan-22 alpha-O-3 beta-ol and (25R)-5,6-epoxyspirostan-22 alpha-O-3 beta,4 beta-diol toward Dowex
Authors: KORDE, SS
BAIG, MHA
DESAI, UR
TRIVEDI, GK
Keywords: starfish saponins
steroidal glycosides
polyhydroxysteroids
efficient
sulfates
acids
Issue Date: 1996
Publisher: BUTTERWORTH-HEINEMANN
Citation: STEROIDS, 61(5), 290-295
Abstract: The acid-catalyzed hydrolytic cleavage of the 5,6-epoxyspirostane derivatives by the cation exchange resin Dowel 50W X8 has been exploited with the goal of developing synthetic protocols toward 3,4,5,6-polyhydroxyspirostane analogs that can serve as intermediates to potential biologically active compounds. Whereas the diastereomers (25R)-5 alpha,6 alpha-epoxyspirostan-22 alpha-O-3 beta-ol and (25R)-5 beta,6 beta-epoxyspirostan-22 alpha-O-3 beta-ol yield two products, (25R)-6 beta-methoxyspirostan-22 alpha-O-3 beta,5 alpha-diol and (25R)-spirostan-22 alpha-O-3 beta,5 alpha,6 beta-triol on Dowex treatment in water-methanol, the alpha- and beta-diastereomers of the 5,6-epoxy derivative of 3 beta,4 beta-diol provide a single product, (25R)-3 beta,6 beta-dihydroxy-5 alpha-spirostan-4-one, in good yields. The structures of these products have been confirmed using H-1 NMR, C-13 NMR, and H-1-H-1 J-correlated spectroscopies. Multifunctional product formation suggests tremendous utility of Dowex in steroid synthesis. The product formation has been rationalized on the basis of differential conformational constraints of the A/B rings of the different epoxides in directing the reaction course. The reaction shows an interesting example of stereoelectronic stereoelectronic effect of a single hydroxy group in discriminating solvent participation.
URI: http://dx.doi.org/10.1016/0039-128X(95)00231-E
http://dspace.library.iitb.ac.in/xmlui/handle/10054/5205
http://hdl.handle.net/10054/5205
ISSN: 0039-128X
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