Galbelgin

Rapid purification of diastereoisomers from Piper kadsura using supercritical fluid chromatography with chiral stationary phases.[Pubmed:28641835]

J Chromatogr A. 2017 Aug 4;1509:141-146.

Supercritical fluid chromatography (SFC) with chiral stationary phases (CSPs) is an advanced solution for the separation of achiral compounds in Piper kadsura. Analogues and stereoisomers are abundant in natural products, but there are obstacles in separation using conventional method. In this paper, four lignan diastereoisomers, (-)-Galbelgin, (-)-Ganschisandrin, Galgravin and (-)-Veraguensin, from Piper kadsura were separated and purified by chiral SFC. Purification strategy was designed, considering of the compound enrichment, sample purity and purification throughput. Two-step achiral purification method on chiral preparative columns with stacked automated injections was developed. Unconventional mobile phase modifier dichloromethane (DCM) was applied to improve the sample solubility. Four diastereoisomers was prepared at the respective weight of 103.1mg, 10.0mg, 152.3mg and 178.6mg from 710mg extract with the purity of greater than 98%.

Asymmetric synthesis of (+)-galbelgin, (-)-kadangustin J, (-)-cyclogalgravin and (-)-pycnanthulignenes A and B, three structurally distinct lignan classes, using a common chiral precursor.[Pubmed:21749139]

J Org Chem. 2011 Aug 19;76(16):6636-48.

The enantioselective synthesis of three structurally distinct classes of lignan from a single, aza-Claisen-derived, chiral morpholine amide is reported. The class of lignan formed is dependent on the substitution pattern in the aryl rings and choice of protecting group on a key benzylic hydroxyl group. The methodology has been used to asymmetrically synthesize and determine the absolute stereochemistry of lignans (+)-cyclogalgravin 3, (-)-pycnanthulignene A 4, (-)-pycnanthulignene B 5, and (-)-kadangustin J 8.

[Neolignans and lignan from Piper wallichii].[Pubmed:20394289]

Zhongguo Zhong Yao Za Zhi. 2010 Jan;35(2):180-2.

To investigate the chemical constituents of the aerial part of Piper wallichii. Nine compounds were isolated by various chromatographic techniques and the structures were elucidated by their physicochemical properties and the spectral data analysis. Nine compounds were identified as one lignan (-)-Galbelgin (1) and eight neolignans: denudatin B (2), hancinone D (3), (+)-licarin A (4), kadsurenone (5), wallichinine (6), hancinone C (7), hancinone B (8), (+)-burchellin (9). Compounds 1, 3, 4, 8, 9 were isolated from this plant for the first time.

Compounds with neuroprotective activity from the medicinal plant Machilus thunbergii.[Pubmed:19555186]

J Enzyme Inhib Med Chem. 2009 Oct;24(5):1117-21.

The dichloromethane fraction of the bark of Machilus thunbergii Sieb. et Zucc. (Lauraceae) significantly protected primary cultures of rat cortical cells exposed to the excitotoxic amino acid, L-glutamate. Through the activity-guided isolation from the CH(2)Cl(2) fraction, (+)-9'-hydroxyGalbelgin (1), isogalcatin B (2), (7S,8S,8'R)-3',4'-dimethoxy-3,4,-methylenedioxylignan-7-ol (3), 1-hydroxy-7-hydroxymethyl-6-methoxyxanthone (4), 5,7-dimethoxy-3',4'-methylenedioxyflavan-3-ol (5), (+)-(3S,4S,6R)-3,6-dihydroxypiperitone (6), protocatechuic acid methyl ester (7) and tyrosol (8) were obtained. All of them had significant neuroprotective activities against glutamate-induced neurotoxicity in primary cultures of rat cortical cells at concentrations ranging from 0.1 microM to 10.0 microM and were comparable to MK-801, a well-known inhibitor of glutamate receptor.

Total synthesis of (-)-talaumidin and (-)-galbelgin.[Pubmed:19408154]

J Asian Nat Prod Res. 2009;11(3):281-7.

( - )-Talaumidin (1) and ( - )-Galbelgin (2) have been synthesized via 4-pentenoic acid as a starting material with the overall yield of about 17.8 and 16.9%, respectively. The key steps include Evans asymmetry anti-aldol reaction, TBS protection, hydroboration, oxidation, Friedel-Crafts arylation, etc.

Stereoselective synthesis of tetrahydrofuran lignans via BF(3) x OEt(2)-promoted reductive deoxygenation/epimerization of cyclic hemiketal: synthesis of (-)-odoratisol C, (-)-futokadsurin A, (-)-veraguensin, (+)-fragransin A(2), (+)-galbelgin, and (+)-talaumidin.[Pubmed:17764190]

Org Lett. 2007 Sep 27;9(20):3965-8.

A versatile route to the synthesis of 2,5-diaryl-3,4-dimethyltetrahydrofuran lignans, (-)-odoratisol C (1), (-)-futokadsurin A (2), (-)-veraguensin (3), (+)-fragransin A2 (4), (+)-Galbelgin (5), and (+)-talaumidin (6), is described. Central to the synthesis of the lignans is BF(3) x OEt(2)-promoted deoxygenation/epimerization of the hemiketal 9a followed by stereoselective reduction of the oxocarbenium ion intermediates 8a,b.