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Methoxyberberine betaine

Betaines of 13-hydroxyberberine and its analogues of general type (190) are easily prepared. Berberine betaine (190, R=H) is obtained by the oxidation of berberine-acetone (191) with potassium permanganate, in a process that invoves a retro-Mannich loss of acetone, and methoxyberberine betaine (190, R= OMe) results from the controlled photo-oxidation of berberine. Other analogues can be prepared by the oxidation of dihydro-and 8-alkyldihydro-berberines. Both (190, R=H) and (190, R= OMe) can be reduced to a mixture of ophiocarpine (192) and the C-13 epimeric epiophiocarpine (M. Hanaoka. C. Mukai and Y. Arata, Heterocycles, 1977, 895). Photo-oxidation of the... [Pg.300]

Photo-oxidation of the methoxyberberine betaine (83) in methanol has been shown to be a novel method of producing the spirobenzylisoquinoline (84) [which may be hydrolysed to the diketone (87)], though the keto-ester (85) and the hemiketal-lactone (86) are other products of the reaction. ... [Pg.105]

The methoxyberberine betaine (83) will undergo acyl migration in aqueous THF to give the imide methyl isoanhydroberberilate (94). That acyl migration had indeed occurred was shown by the conversion of the betaine (83) into the acetoxy-enamine (95) by acetic anhydride and pyridine, followed by hydrolysis of this by methanolic potassium hydroxide to the known methyl anhydroberberilate (97). The two isomeric compounds (94) and (97) react differently when treated with sodium borohydride in ethanol, the former suffering only solvolysis to noroxy-hydrastinine (98) and the diester (99) and the latter reduction to the ortho-ester (96). This ortho-ester, on A -methylation and further reduction with sodium borohydride, yields hydrohydrastinine and i -meconine. ... [Pg.106]


See other pages where Methoxyberberine betaine is mentioned: [Pg.91]    [Pg.523]   
See also in sourсe #XX -- [ Pg.300 ]




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