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Protoberberine alkaloids transformation reactions

Although C—O bond cleavage is of little importance for transformations of protoberberines to other types of alkaloids, the selective C—O bond cleavage reaction provides access to naturally unabundant or nonnatural protoberberines from naturally abundant protoberberines such as berberine. [Pg.153]

Ring D inversion seems to be a crucial step in biogenetic transformations of protoberberines to related alkaloids such as rhoeadine, retroprotoberberine, spirobenzylisoquinoline, and indenobenzazepine alkaloids. 8,14-Cyclober-bin-13-ol 478 derived from berberine (15) was successively treated with ethyl chloroformate, silver nitrate, and pyridinium dichromate (PDC) in dimethyl-formamide to give the keto oxazolidinone 479 (Scheme 98). Heating of 479 with 10% aqueous sodium hydroxide in ethanol effected hydrolysis, retro-aldol reaction, cyclization, and dehydration to provide successfully the... [Pg.218]

See other pages where Protoberberine alkaloids transformation reactions is mentioned: [Pg.141]    [Pg.143]    [Pg.159]    [Pg.173]    [Pg.193]    [Pg.197]    [Pg.207]    [Pg.211]    [Pg.213]    [Pg.223]    [Pg.225]    [Pg.227]    [Pg.229]    [Pg.416]    [Pg.339]    [Pg.293]    [Pg.285]    [Pg.431]    [Pg.383]    [Pg.394]    [Pg.318]    [Pg.343]    [Pg.418]    [Pg.432]    [Pg.249]    [Pg.265]    [Pg.506]    [Pg.385]    [Pg.220]    [Pg.267]    [Pg.261]    [Pg.547]    [Pg.276]   
See also in sourсe #XX -- [ Pg.33 , Pg.141 ]



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Alkaloids protoberberines

Protoberberine

Protoberberine alkaloids

Protoberberine alkaloids, transformation

Reaction transform

Transformation reaction

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