O-Methylbalfourodinium salt

O-Methylbalfourodinium salt (11) is the major quaternary alkaloid of young Brazilian trees of the Balfourodendron riedelianum Engl, species... 

Dihydroisopropylfuroquinoline alkaloids, e.g., balfourodine (100), hydroxydimethylpyran derivatives such as isobalfourodine (104), and hydroxyisopropyl derivatives of the lunasine type contain a single chiral center at the 2-position of the prenyl side chain. In order to obtain sufficient quantities of the alkaloids to study their absolute stereochemistry, methods of asymmetric synthesis were developed by Grundon and co-workers (78-80). Reaction of 3-isoprenylquinolones (98) with chiral peroxy acids furnished balfourodine (100), O-methylbalfourodinium salt (101) isobalfourodine (104), and balfourolone (103), as illustrated in Scheme 5, with... 

Support for the new mechanism was provided by trapping the intermediate with methyl iodide to give epoxide 133. The structure of this compound was indicated by IR absorption at 1646 cm- (2-quinolone carbonyl) and by the NMR spectrum. The epoxide was converted readily into the diol balfourolone (135) on alumina chromatography or by treatment with 2 N sodium hydroxide at 20° the mild conditions and the failure of 2,4-dimethoxyquinoline epoxides (e.g., 109) to react under similar conditions suggest that this reaction occurs through formation of O-methylbalfourodinium salt (134) and subsequent nucleophilic attack at the 2-position rather than by direct reaction of hydroxide ion on the epoxide ring. Epoxide 133 is the presumed intermediate in reaction of 4-methoxy-... 

N-methyIplatydesminium salt, R=H, 67 pteleatinium salt,R=OH,68 O-methylbalfourodinium salt, R=OMe,69... 

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See also in sourсe #XX -- [ , , , , , ]

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