Criofolinine and Vernavosine, New Pentacyclic Indole Alkaloids Incorporating Pyrroloazepine and Pyridopyrimidine Moieties Derived from a Common Yohimbine Precursor

• Published in: Organic letters Vol. 16; no. 24; pp. 6330 - 6333
• Main Authors: Nge, Choy-Eng, Gan, Chew-Yan, Lim, Kuan-Hon, Ting, Kang-Nee, Low, Yun-Yee, Kam, Toh-Seok
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 19.12.2014; Amer Chemical Soc
• Subjects: Azepines - chemistry; Chemistry; Chemistry, Organic; Indole Alkaloids - chemistry; Indole Alkaloids - isolation & purification; Magnetic Resonance Spectroscopy; Molecular Structure; Physical Sciences; Plant Leaves; Pyrimidines - chemistry; Science & Technology; Stereoisomerism; Tabernaemontana - chemistry; X-Ray Diffraction; Yohimbine - chemistry; TABERNAEMONTANA; A-D; BISINDOLE ALKALOIDS; JERANTININE; LEAVES
• ISSN: 1523-7060; 1523-7052
• DOI: 10.1021/ol503072g

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.