- STUDIES ON OXIDATI0N OF TRITERPENOIDS: PART VII. TRANSFORMATION OF OLEANANE AND URSANE SKELETONS TO 11α,12α-OXIDOTRITERPENOIDS WITH HYDROGEN PEROXIDE AND SELENIUM DIOXIDE AND THEIR CARBON-13 NMR DATA.
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Hydrogen peroxide-selenium dioxide in t-butanol has been found to be a good reagent for the preparation of 11α,12α-oxidotriterpenoids of oleanane and ursane skeletons; whereas α-amyrin and β-amyrin acetates furnished 11α,12α-epoxyurs-14-en-3β-yl acetate (4c) and 11α,12α-epoxytaraxer-14-en-3β-yl acetate (4a) respectively, uvaol and ursolic acid/methyl ester gave 11α,12α-epoxyurs-28->13-olide-3β-ol (5d); erythrodiol (3c) and oleanolic acid (3b)/methyl ester (3d) afforded 11α,12α-epoxy-oleanan-28->13-olide-3β-ol (5); olean-12-en-2α,3β,28-yl triacetate (3j) on similar reaction furnished 11α,12α-epoxytaraxer-14-en-3β-ol-2α,28-yl diacetate (4d) and 11α,12α-epoxytaraxer-14-en-2α,3β-diol-28-ylacetate (4e).
- Pradhan, Bhim Prasad,Chakraborty, Satyajit,Weyerstahl, Peter
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- Rearrangement and oxidation of β-amyrin promoted by growing cells of Lecanicillium muscarinium
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Microbial transformation of β-amyrin by growing cells of the fungus Lecanicillium muscarinium (former Cephalosporium aphidicola) was successfully accomplished after 15 days of incubation with orbital shaking at 120 rpm. Two products purified by column chr
- Martins, Leonardo Ribeiro,Takahashi, Jacqueline Aparecida
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experimental part
p. 767 - 774
(2010/09/07)
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