Revisit to 25R/25S Stereochemical Analysis of Spirostane-type Steroidal Sapogenins and Steroidal Saponins via 1H NMR Chemical Shift Data
2012 ◽
Vol 7
(6)
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pp. 1934578X1200700
Keyword(s):
H Nmr
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An approach based on the difference (Δab = δa – δb) between 1H NMR chemical shifts (δa, δb) of the geminal protons of oxymethylene (H2-26) (Δab = <0.2 for 25 R; Δab = >0.5 for 25 S) is proposed for ascertaining 25 R/25 S orientation of the 27-methyl group for (22 R)-spirostane-type steroidal sapogenins and steroidal saponins. These studies suggested the 25 R-orientation of the 27-Me group for the steroidal saponins isolated by Temraz et al. from Tribulus alatus.
1999 ◽
Vol 289
(1-2)
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pp. 11-19
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2015 ◽
Vol 2015
(6)
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pp. 1320-1324
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Keyword(s):
1977 ◽
Vol 55
(17)
◽
pp. 3161-3165
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1975 ◽
Vol 53
(19)
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pp. 2880-2890
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