- CONTRIBUTIONS TO THE STUDY OF EPIMERIZATION OF POLYPEPTIDIC ERGOT ALKALOIDS AT C-8
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The influence of pH and nature of the solvent upon the epimerization rate of polypeptidic ergot alkaloids (ergotamine, ergocristine, ergocryptine and ergocornine) at C-8 was studied.It was established that, in aqueous solutions, epimerization is minimum within 2.5-4.0 pH range.The first-order rate constants of epimerization in various organic solvents of the alkaloids in question were evaluated; they have shown that the epimerization rate is maximum in methanol, which is the most polar of the solvents tested.Epimerization at C-8 of ergotamine is a first-order reaction over a time interval much shorter than in epimerization of alkaloids from ergotoxine group, more so with methanol as solvent.Ether, chloroform and benzene have ensured an adequate stability.
- Bandula, Rodica,Vasilescu, Marilena
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p. 1189 - 1196
(2007/10/03)
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