B. P. Pradhan

A triterpenoid lactone from Leucas aspera

Abstract Leucolactone, isolated from the root of Leucas aspera has been characterized as 3β,16α-dihydroxyoleanan-28→13β-olide on the basis of 1 H, 13 C NMR, 2D NMR and mass spectral analysis.

Triterpenoid acids from Sapium sebiferum

Abstract Sebiferenic acid, isolated from the bark of Sapium sebiferum , has been characterized as 2α,3β-dihydroxytaraxer-14-en-28-oic acid on the basis of 1 H NMR, 13 C NMR and mass spectral evidence and chemical transformations. The structure of sebiferic acid has been revised.

Studies on oxidation of triterpenoids: part vii. Transformation of oleanane and ursane skeletons to 11α, 12α-oxidotriterpenoids with hydrogen perox

Abstract 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-oleanam-28→13-olide-3β-ol ( 5 ) ; oleam-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-yl acetate ( 4e ).

Three new friedelane lactones from the bark of gynocardia odorata (flacourtiaceae)

Abstract Three new triterpenes - odolactone, acetylodollactone and odollactone from the bark of Gynocardia odorata have been characterised as 3-keto, 3,α-O-acetyl and 3α(-hydroxyl derivatives of friedelan-26→12β-lactone respectively.

Diterpenoid lactones from the roots of Gynocardia odorata

Three new diterpenoid lactones, odolide iso-odolide and hydroxy odolide, isolated from the roots of Gynocardia odorata have been characterized as ent-kaur-15(16)-en-19 → 20-olide, ent-kaur-16(17)-en-19 → 20-olide and 16α-hydroxy-ent-kauran-19 → 20-olide on the basis of spectral and chemical analysis. The higher terpenoids isolated were odolactone, trichadenic acid-A and β-sitosterol.

A single pot synthesis of 3,4-seco acid from 4,4-dimethyl-3-keto triterpenoid

Abstract Oxidation of 4,4-dimethyl-3-keto triterpenoid with m-CPBA in presence of p-TsOH furnishes 3,4-seco triterpenoid acid whereas 4-mono-methyl-3-keto-triterpenoid affords only the ϵ-lactone under the identical condition.

Reduction of ketones to epimeric alcohols with potassium hydroxide-diethylene glycol

Abstract Triterpenoid ketones have been reduced to epimeric alcohols on boiling with potassium hydroxide in diethylene glycol. κ, β -unsaturated ketone furnished saturated epimeric alcohols.

Action of hydrogen peroxide on olean-12,15-dien-3,11-diol: preparation of c-nor-triterpene lactones

Abstract Treatment of olean-12,15-dien-3,11-diol with hydrogen peroxide containing p-toluenesulphonic acid furnished two isomeric γ-lactones identified as 3β-acetates of C-12-nor-olean-15-en-13α-carb →19α-olide and C-12-nor-olean-18(19)-en-13β-carb→15β-olide.