title: Criofolinine and vernavosine, new pentacyclic indole alkaloids incorporating pyrroloazepine and pyridopyrimidine moieties derived from a common yohimbine precursor.
abstract: Two new indole alkaloids characterized by previously unencountered natural product skeletons, viz., criofolinine (1), incorporating a pyrroloazepine motif within a pentacyclic ring system, and vernavosine (2, isolated as its ethyl ether derivative 3, which on hydrolysis regenerated the putative precursor alkaloid 2), incorporating a pyridopyrimidine moiety embedded within a pentacyclic carbon framework, were isolated from a Malayan Tabernaemontana species. The structures and absolute configuration of these alkaloids were determined on the basis of NMR and MS analysis and confirmed by X-ray diffraction analysis.
authors.affiliation: Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia.
authors.forename: Choy-Eng
authors.initials: CE
authors.lastname: Nge
authors.forename: Chew-Yan
authors.initials: CY
authors.lastname: Gan
authors.forename: Kuan-Hon
authors.initials: KH
authors.lastname: Lim
authors.forename: Kang-Nee
authors.initials: KN
authors.lastname: Ting
authors.forename: Yun-Yee
authors.initials: YY
authors.lastname: Low
authors.forename: Toh-Seok
authors.initials: TS
authors.lastname: Kam
mesh_terms: D001381:Azepines / Q000737:chemistry*; D026121:Indole Alkaloids / Q000737:chemistry* / Q000302:isolation & purification; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D018515:Plant Leaves; D011743:Pyrimidines / Q000737:chemistry*; D013237:Stereoisomerism; D030014:Tabernaemontana / Q000737:chemistry*; D014961:X-Ray Diffraction; D015016:Yohimbine / Q000737:chemistry*
chemical_list: D001381:Azepines; D026121:Indole Alkaloids; D011743:Pyrimidines; C000600317:criofolinine; C000600318:vernavosine; D015016:Yohimbine