Koh Kaneko

Five glycosides from the Chinese drug Tong-guang-san: the stems of Marsdenia tenacissima

Abstract Five new glycosides were isolated from the Chinese crude drug ‘Tong-guang-san’: the stems of Marsdenia tenacissima (Roth.) Wight et Arn. (Asclepiadaceae). The structures of tenacissosides A-E were deduced on the basis of chemical and spectral evidence as tenacigenin B-I 3- O -β- D -glucopyranosyl-(1→4)-3- O -methyl-6-deoxy-β- D - allopyranosyl-(1→4)-β- D -oleandropyranoside, tenacigenin B-II 3- O -β- D -glucopyranosyl-(1 →4)-3- O -methyl-6-deoxy- β- D allopyranosyl-(1 →4)-β- D -oleandropyranoside, tenacigenin B-III 3- O -β- D glucopyranosyl-(1→4)-3- O -methyl-6- deoxy-β- D -allopyranosyl-(1 → 4)-β- D -oleandropyranoside, tenacigenin B-IV 3- O -β- D -glucopyranosyl-(1 →4)-3- O - methyl-6-deoxy-β- D -allopyranosyl-(1 → 4)-β- D -oleandropyranoside and tenacigenin B-V 3- O -β- D -glucopyranosyl- (1 → 4)-3- O -methyl-6-deoxy-allopyranosyl-(1 → 4)-β- D -oleandropyranoside, respectively.

A steroidal alkaloid from Fritillaria ebeiensis

Abstract A unique steroidal alkaloid with a 5β-hydroxyl group, ebeietinone, was isolated from the bulbs of Fritillaria ebeiensis var. purpurea . Its structure was determined by means of MS, 1 H NMR and 13 C NMR and confirmed by X-ray crystallography.

Four pregnane glycosides, boucerosides AI, AII, BI and BII, from Boucerosia aucheriana

Abstract Four new glycosides were isolated from Boucerosia aucheriana. The structures of boucerosides AI, AII, BI, and BII were deduced on the basis of chemical and spectral evidence as boucerogenin I 3-O-β- d -glucopyranosyl-(1→4)-6-deoxy-3-O-methyl-β- d -allopyranosyl-(1→4)-β- d -oleandropyranosyl-(1→4)-β- d -cymaropyranoside, boucerogenin II 3-O-β- d -glucopyranosyl-(1→4)-6-deoxy-3-O-methyl-β- d -allopyranosyl-(1→4)-β- d -oleandropyranosyl-(1→4)-β- d -cymaropyranoside, boucerogenin I 3-O-β- d -glucopyranosyl-(1→4)-6-deoxy-3-O-methyl-β- d -allopyranosyl-(1→4)-β- d -cymaropyranosyl-(1→4)-β- d -cymaropyranoside, and boucerogenin II 3-O-β- d -glucopyranosyl-(1→4)-6-deoxy-3-O-methyl-β- d -allopyranosyl-(1→4)-β- d -cymaropyranosyl-(1→4)-β.

Conversion of solanidine to jerveratrum alkaloids in Veratrum grandiflorum

Abstract Etiolated Veratrum grandiflorum Loesen. fil. accumulates solanidyl glycoside in the leaf, and this glycoside is converted into jerveratrum alkaloids in the rhizome during subsequent illumination.

Solanopubamine, a steroidal alkaloid from Solanum pubescens

Abstract Aerial parts of Solanum pubescens yielded a new steroidal alkaloid, solanopubamine, the structure of which was elucidated as 3β-amino-5α,22αH,25βH-solanidan-23β-ol by 13 C NMR, 1 H NMR, IR, mass spectral analysis and chemical degradation methods.

New steroidal alkaloids having a novel seven ring skeleton from fritillaria ussuriensis maxim

Abstract Two new steroidal alkaloids having a novel seven ring skeleton, ussurienine ( 1 ) and ussurienone ( 2 ), were isolated from the HCI-MeOH hydrolyzed alkaloid fraction of Fritillaria ussuriensis Maxim. (Ping-bei-mu). Continuous study on the same plant, however, showed that 1 and 2 were the artifacts derived from ussuriedine ( 3 ) and ussuriedinone ( 4 ), which were isolated from the free alkaloids fraction. Their structures were elucidated on the basis of spectral data, X-ray crystal analysis and chemical conversion.

New steroidal alkaloids from fritillaria ussuriensis maxim. Pingbeinone and Heilonine

Abstract Two novel alkaloids, pingbeinone (1) and heilonine (2) were isolated from Fritillaria ussuriensis and their structures were determined on the basis of spectral data and X-ray crystallographic analysis. Pingbeinone is novel C26 steroidal alkaloid having a skeleton lacking C-18 of C-nor D-homo steroidal alkaloid.

Pingbeinone, a novel steroidal alkaloid having C-18 nor cevane skeleton from Fritillaria ussuriensis Maxim

Abstract A novel stroidal alkaloid, having C-18 nor cevane skeleton, pingbeinone ( 1 ), was isolated from Fritillaria ussuriensis Maxim. The structure was established by X-ray crystallographic analysis of its hydrogen iodide.