Kopsiyunnanines F and isocondylocarpines: new tubotaiwine-type alkaloids from Yunnan Kopsia arborea

Abstract

Five new alkaloids, including three 19,20-epoxytubotaiwine stereoisomers, viz. kopsiyunnanines F1 (1), F2 (2), and F3 (3), (Z)-isocondylocarpine (4), and (Z)-isocondylocarpine N-oxide (5), along with five known tubotaiwine-type indole alkaloids were isolated from the aerial part of Yunnan Kopsia arborea Blume (Apocynaceae). Their structures including absolute configurations were elucidated by spectroscopic and chemical means.

Isolation and Structural Elucidation of Compounds from Pleiocarpa bicarpellata and Their In Vitro Antiprotozoal Activity

“…The experimental spectrum ( Figure 4 ) showed negative Cotton effects (CE) at 211 and 238 nm and positive CE at 201, 259, and 315 nm that matched well with the calculated ECD curve for 7 S , 15 R , 20 R , and 21 S . These configurations are different from those described for tubotaiwine, which were 7S , 15S , 20S , and 21R [ 36 ]. Compound 15 was identified as methyl ( 7S,15R,20R,21S )-20-ethyl-5,6,14,15,21-hexahydro-15,21-ethanopyrrolo[5,21- d ]carbazole-16-carboxylate-methane and named ( 7S,15R,20R,21S )-tubotaiwine.…”

Total Synthesis of (+)-Condylocarpine, (+)-Isocondylocarpine, and (+)-Tubotaiwine

“…During our recent total synthesis of the structurally unique indole alkaloid (−)-actinophyllic acid, we developed a concise synthesis of the hexahydro-1,5-methano-1 H -azocino[4,3- b ]indole ring system. , A central step in this synthesis is an iron(III)-promoted intramolecular oxidative coupling of malonate and ketone enolates generated from indole piperidones 6 to deliver hexahydro-1,5-methano-1 H -azocino[4,3- b ]indole-12-ones 7 (eq ). Ketone (1 S ,5 R )- 7b was prepared in enantioenriched form (er = 95:5) in 26% overall yield from 4-( tert -butoxycarbonylamino)butyric acid by way of six isolated intermediates. , Herein we report the use of tetracyclic intermediate (1 S ,5 R )- 7b for the enantioselective synthesis of three representative members of the condylocarpine subtype of the aspidospermatan group of alkaloids. , …”

Total Syntheses of <i>Lycopodium</i> and Monoterpenoid Indole Alkaloids Based on Biosynthesis-Inspired Strategies

“…Strictosidine (45), which is biosynthesized by the condensation of tryptamine (43) and secologanin (44), is the key intermediate for the in vivo elaboration of numerous groups of monoterpenoid indole alkaloids having rich structural di-versity. 31) According to their structural characteristics, monoterpenoid indole alkaloids are classified into four major types (with many subdivisions), i.e., Corynanthe, Strychnos, Aspidosperma, and Iboga.…”

“…Total Synthesis and Structure Elucidation of Kopsiyunnanine K The genus Kopsia, which belongs to Family Apocynaceae, is a rich source of monoterpenoid indole alkaloids possessing structural diversity as well as a wide range of biological activities. 37) As a result of our continuing chemical studies on novel bioactive alkaloids, we were able to accomplish the structure elucidation of several unique monoterpenoid indole alkaloids from Kopsia arborea native to Yunnan Province in China [38][39][40][41][42][43][44][45][46] (Chart 19).…”