7a-Hydroxyisoatisine

The chemical work on ajaconine has been reviewed (<5) in Volume XII of this treatise. Recently, Pelletier and Mody reported (57) an unusual rearrangement of ajaconine to 7a-hydroxyisoatisine (82) via a disfavored 5-endo-trigonal ring closure, which is discussed in Section V. 

Recently, Pelletier and Mody (87) reported an unusual rearrangement of ajaconine (80), via a disfavored 5-endo-trig ring closure, to the more stable oxazolidine ring-containing compound, 7a-hydroxyisoatisine (82). They called attention to apparent violations of Baldwin s cyclization rules (151)... 

Refluxing ajaconine in methanol afforded a mixture from which a new compound identified (87) as 7a-hydroxyisoatisine (82) was isolated. The structure of the latter was established by 1H- and UC-NMR spectroscopy. When ajaconine was refluxed in CH3OD under nitrogen, a mixture of C-19, C-20-deuterated ajaconine (206) and C-19,C-20-deuterated 7 -hydroxy-isoatisine (207) was formed. Incorporation of deuterium in 206 and 207 indicated that ajaconine ionized and rearranged to 207 and that these species are in equilibrium in refluxing methanol. 

Pelletier and Mody (87) have studied the behavior of ajaconine (88) in ionic and nonionic solvents with the aid of 13C-NMR spectroscopy. They established the structure of 7a-hydroxyisoatisine (82) and reported the 13C-NMR spectra of 80, 82, atisinium chloride (5), and ajaconium chloride (203). 

The alkaloid ajaconine (33) undergoes an unusual rearrangement to 7a-hydroxyisoatisine (34) on heating in methanol. 

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