title: Transformations of the 2,7-Seco Aspidosperma alkaloid leuconolam, structure revision of epi-leuconolam, and partial syntheses of leuconoxine and leuconodines A and F.
abstract: Several transformations of the seco Aspidosperma alkaloid leuconolam were carried out. The based-induced reaction resulted in cyclization to yield two epimers, the major product corresponding to the optical antipode of a (+)-meloscine derivative. The structures and relative configuration of the products were confirmed by X-ray diffraction analysis. Reaction of leuconolam and epi-leuconolam with various acids, molecular bromine, and hydrogen gave results that indicated that the structure of the alkaloid, previously assigned as epi-leuconolam, was incorrect. This was confirmed by an X-ray diffraction analysis, which revealed that epi-leuconolam is in fact 6,7-dehydroleuconoxine. Short partial syntheses of the diazaspiro indole alkaloid leuconoxine and the new leuconoxine-type alkaloids leuconodines A and F were carried out.
authors.affiliation: Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia.
authors.forename: Yun-Yee
authors.initials: YY
authors.lastname: Low
authors.forename: Fong-Jiao
authors.initials: FJ
authors.lastname: Hong
authors.forename: Kuan-Hon
authors.initials: KH
authors.lastname: Lim
authors.forename: Noel F
authors.initials: NF
authors.lastname: Thomas
authors.forename: Toh-Seok
authors.initials: TS
authors.lastname: Kam
mesh_terms: D030009:Aspidosperma / Q000737:chemistry; D001381:Azepines / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D018360:Crystallography, X-Ray; D003500:Cyclization; D026121:Indole Alkaloids / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D015394:Molecular Structure; D024301:Plant Bark / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D001381:Azepines; D026121:Indole Alkaloids; C000590192:leuconodine A; C000590193:leuconodine F; C000590191:leuconoxine; C062173:leuconolam