32337-26-1Relevant articles and documents
Synthesis of 25-oxygenated D:A-friedooleananes: Part IV - Studies on the structure of roxburghonic acid
Ghosh, S. K.,Datta, S. K.,Das, Saktipada
, p. 370 - 371 (2007/10/02)
Structure of the natural product roxburghonic acid (1) has been established by its synthesis from purtanjivadione (2).Compound 2 is converted into 3β-acetoxy-7β,25-oxido-D:A-friedooleanane (3) by the literature method.The latter on oxidation with CrO3-AcOH gives 3β-acetoxy-D:A-friedoolean-7β 25-olide (4) which is hydrolysed with 5percent methanolic KOH solution to yield 3β-hydroxyolide (5).The lactone 5 on treatment with lithium in boiling ethylenediamine affords 3β-hydroxy-D:A-friedoolean-25-oic acid (6) which on oxidation with CrO3 in pyridine yields 1.The structure of 1 has been confirmed by its elemental analyses and spectral (IR, PMR and mass) data and also by esterification with diazomethane to give methyl roxburghonate (7).
TWO NEW ANGULAR METHYL DIOXYGENATED D:A-FRIEDO-OLEANANES
Weeratunga, Gamini,Kumar, Vijaya,Sultanbawa, M. Uvais S.
, p. 2031 - 2032 (2007/10/02)
Two new trioxygenated D:A-friedo-oleananes from Elaeodendron glaucum have been shown to be the angular methyl dioxygenated 25,28-dihydroxy-D:A-friedo-oleanan-3-one(1) and 3,28-dioxo-D:A-friedo-oleanan-25-ol(2) by interconversion and deoxygenation of the alcohol(2) using Lithium-ethylene diamine reduction coupled with spectroscopic methods.
