ABsmcT.-Three new azafluorene alkaloids were isolated from Oxandra xylopioidies. The structures of the alkaloids, as determined by organic syntheses andor spectral analyses, were shown to be 4-azafluorenones, 6-hydroxyonychine [3),5-hydroxy-6-methoxyonychine 141, and 2,6-dimethoxy-7-hydroxyonychine 15). The syntheses also provided three additional azaflourenone alkaloids, which were identified as 5,6-dimethoxyonychine 161, 8-hydroxyonychine [n, and 5,8dimethoxyonychine 181. The physical and spectral properties of these azafluorene alkaloids are discussed.In 1976, De Almeida et a f . (1) isolated the novel alkaloid onychine from Onychopetafum arnuzonicum (Annonaceae). Its structure was assigned as 1-aza-4-methylfluoren-9-one 111. In 1979, Koyama et a f . (2) synthesized both 1-aza-4-methylfluoren-9-one E l ] and its structural isomer, l-methyl-4-azafluoren-9-one 121. Based upon the nmr data of these synthetic products and onychine, they suggested that the structure of onychine be revised to l-methyl-4-azafluoren-9-one 121, although a direct comparison of the synthetic products with onychine was not carried out. Later, reference (3) to and isolation [from Cfeistophofispatm (Annonaceae)] (4) of onychine still regarded the structure as 1. This was also the case when 6-methoxyonychine was reported (5) without reference to the revised (2) structure for onychine.In our laboratory three new alkaloids were isolated from Oxandra xyfopioides Diels (Annonaceae). Spectral data suggested they were onychine analogues. At this point erroneous structures were published (6,7) for these compounds, based upon the prior references that regarded the structure of onychine as 1. In view of the uncertainty of the structure of onychine, synthetic methods were employed to produce several 4-azaflouren-9-one derivatives via phenylnicotinic acids (8) in order to establish firmly the structures of the isolates.The three alkaloids isolated from 0. xyfopioih were shown to be 6-hydroxyonychine {37, 5-hydroxy-6-methoxyonychine 141, and 2,6-dimethoxy-7-hydroxyonychine 151. The syntheses provided three additional azafluorene alkaloids, 5,6-dimethoxyonychine 167, 8-hydroxyonychine 17, and 5,8-dimethoxyonychine 181.The uv and ir data of the three natural products indicated they were analogues of onychine ( l-methyl-4-azafluoren-9-one) [ 2 ] . The mass spectra showed molecular ions at m/z 2 11 (16 amu higher than 2), 24 1 (46 amu larger than 2), and 27 1 (76 arnu higher than 2) suggesting hydroxy-, hydroxy-methoxy-, and dimethoxy-hydroxy-derivatives, respectively.
