Studies on Indian medicinal plants—XXXIX : Reinvestigation of the lactones and bromo derivative of betulinic acid |
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Authors: | B Achari SC Pakrashi |
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Institution: | Indian Institute of Experimental Medicine, Calcutta-700032, India |
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Abstract: | Isobornyloxy aluminium dichloride reduction of the ketolactone 2a of betulinic acid (1a) gave the axial alcohol 2b as the preponderant product. Hydroxylactone B of 1a therefore must have the equatorial OH function contrary to our previous conclusion. The so-called “hydroxylactone A” has been found to be the ring A rearranged product 3a. Reexamination of earlier work has shown that 1a yields a mixture of 2e and 5a in presence of HBr-AcOH, and a mixture of 2d and 3a with refluxing formic acid. Bromination of 1a affords 1e. |
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