Phenanthridinium-2-olates

Oxidation of the alkaloid lycorine (359) gives a red, hygroscopic solid which readily forms salts with mineral acids. This product, which has been assigned the betaine structure 358, has also been obtained from Ungernia minor and named ungeremine. . zss TV-methyl derivative (357 R = Me, R R = OCH2O) has also been described.  

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Demethylvasconine (85) (9-methoxy-5-methyl-phenanthridin-8-olate) presented in Scheme 31 was found in Crinum kirkii (95P1291) (Amaryllidaceae). Although published as cation, no information about the anion of this alkaloid is given. Its relationship to other alkaloids of this class, however, makes a betainic structure more than likely and this is confirmed by a comparison of the NMR data of 85 with the cationic and betainic alkaloids presented in Table III. This betaine is isoconjugate with the 2-methylphenanthrene anion and thus defined the alkaloid as a member of class 1 (odd alternant hydrocarbon anions). Whereas substitution of the isoconjugate phenanthridinium moiety at the 1-position with an anionic fragment results in zwitterions (cf. Section III.D), the phenanthridinium-2-olate is a mesomeric betaine. 

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