Oxidation of vincristine

The participation of peroxidase in the metabolism of alkaloids has frequently been described in the literature [42,50,52,150,151], However, the participation of peroxidase in alkaloid metabolism is generally associated with alkaloid turnover and catabolism, which generally reduces the biological (pharmacological) activity of such compounds [152-154]. This is the case of the oxidation of vincristine (XLV) by peroxidase to lead to N-formyl-catharinine (XLVI) [154] (Scheme XXIII). 

It was previously known that oxidation of vinblastine sulfate with chromyl acetate leads to vincristine 471). Szantay and coworkers have found that a similar oxidation carried out on the free base 665 led instead to the cyclic derivative, 756, in which the original velbanamine part has undergone a 3, 7 -transannular cyclization into a i/ -aspidosperma-type skeleton. Similar oxidation of vincristine (666) led to the corresponding cyclized product 757. Acid treatment of the cyclized derivatives resulted in an aspidospermane- eburnane skeletal rearrangement leading to novel bisindoles with the i/ -eburnea-aspidosperma-type skeleton, e.g., 756 758 472). 

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See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ , ]

See also in sourсe #XX -- [ ]

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