Chemical and Pharmaceutical Bulletin
Online ISSN : 1347-5223
Print ISSN : 0009-2363
ISSN-L : 0009-2363
Chemical Transformation of Protoberberines. VI. Ring D Inversion of Protoberberine Alkaloids. Conversion of Berberine into Non-naturally Occurring 11, 12-Oxygenated Protoberberines via Spirobenzylisoquinolines
MIYOJI HANAOKAMITSURU INOUEMISAO TAKAHASHISHINGO YASUDA
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Keywords: oxazolidinone ring
JOURNAL FREE ACCESS

1984 Volume 32 Issue 11 Pages 4431-4436

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Abstract

Three methods were developed for the transformation of naturally occurring 9, 10-oxygenated protoberberines into non-naturally occurring 11, 12-oxygenated protoberberines through ring D inversion via spirobenzylisoquinolines. Berberine (14) was converted to the spirobenzylisoquinoline (18) through regioselective cleavage of the 8, 14-cycloberbine (17). Alkaline hydrolysis of the oxazolidinone (20) derived from 18 efficiently afforded the 11, 12-oxygenated protoberberine (23), which was also obtained from 8-methoxyberberinephenolbetaine (24) through treatment of the keto-hydroxy-spirobenzylisoquinoline (25) with alkali. The spirobenzylisoquinoline (26) derived from the 8, 14-cycloberbine (16) was subjected to hydrogenolysis and subsequent hydrolysis to give the amino-ketone (28), photolysis of which furnished the 11, 12-oxygenated protoberberine (29).

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© The Pharmaceutical Society of Japan
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