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Spirobenzylisoquinoline alkaloids cyclization

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 also in sourсe #XX -- [ Pg.2 ]

See also in sourсe #XX -- [ Pg.1040 ]

See also in sourсe #XX -- [ Pg.1040 ]

See also in sourсe #XX -- [ Pg.2 ]

See also in sourсe #XX -- [ Pg.1040 ]



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Spirobenzylisoquinoline

Spirobenzylisoquinoline alkaloids

Spirobenzylisoquinolines

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