527-06-0Relevant articles and documents
Characteristic alkaline catalyzed degradation of kotalanol, a potent α-glucosidase inhibitor isolated from Ayurvedic traditional medicine Salacia reticulata, leading to anhydroheptitols: another structural proof
Muraoka, Osamu,Xie, Weijia,Osaki, Satomi,Kagawa, Ayumi,Tanabe, Genzoh,Amer, Mumen F.A.,Minematsu, Toshie,Morikawa, Toshio,Yoshikawa, Masayuki
, p. 3717 - 3722 (2010)
Stereochemical structure of kotalanol (2), a highly potent α-glucosidase inhibitor isolated from an Ayurvedic traditional medicine Salacia reticulata, was proved by alkaline catalyzed degradation of natural kotalanol (2), in which characteristic stereospecific cyclization of the degradative side chain leading to anhydroheptitols (10 and 11) was involved.
Organocatalytic Synthesis of Higher-Carbon Sugars: Efficient Protocol for the Synthesis of Natural Sedoheptulose and d-Glycero-l-galacto-oct-2-ulose
Popik, Oskar,Pasternak-Suder, Monika,Ba?, Sebastian,Mlynarski, Jacek
, p. 717 - 721 (2016/08/27)
Herein we report a short and efficient protocol for the synthesis of naturally occurring higher-carbon sugars—sedoheptulose (d-altro-hept-2-ulose) and d-glycero-l-galacto-oct-2-ulose—from readily available sugar aldehydes and dihydroxyacetone (DHA). The key step includes a diastereoselective organocatalytic syn-selective aldol reaction of DHA with d-erythrose and d-xylose, respectively. The methodology presented can be expanded to the synthesis of various higher sugars by means of syn-selective carbon–carbon-bond-forming aldol reactions promoted by primary-based organocatalysts. For example, this methodology provided useful access to d-glycero-d-galacto-oct-2-ulose and 1-deoxy-d-glycero-d-galacto-oct-2-ulose from d-arabinose in high yield (85 and 74 %, respectively) and high stereoselectivity (99:1).
Structure proof and synthesis of kotalanol and de-O-sulfonated kotalanol, glycosidase inhibitors isolated from an herbal remedy for the treatment of type-2 diabetes
Jayakanthan, Kumarasamy,Mohan, Sankar,Pinto, B. Mario
body text, p. 5621 - 5626 (2009/09/24)
Kotalanol and de-O-sulfonated-kotalanol are the most active principles in the aqueous extracts of Salacia reticulata which are traditionally used in India, Sri Lanka, and Thailand for the treatment of diabetes. We report here the exact stereochemical structures of these two compounds by synthesis and comparison of their physical data to those of the corresponding natural compounds. The candidate structures were based on our recent report on the synthesis of analogues and also the structure-activity relationship studies of lower homologues. The initial synthetic strategyrelied on the selective nucleophilic attack of p-methoxybenzyl (PMB)-pr otected 4-thio-D-arabinitol at the least hindered carbon atom of two different, selectively protected 1,3-cyclic sulfates to afford the sulfonium sulfates. The protecting groups consisted of a methylene acetal, in the form of a seven-membered ring, and benzyl ethers. Deprotection of the adducts yielded the sulfonium ions but also resulted in de-O-sulfonation. Comparison of the physical data of the two adducts to those reported for de-O-sulfonated natural kotalanol yielded the elusive structure of kotalanol by inference. The side chain of this compound was determined to be another naturally occurring heptitol, D-perseitol (D-glycero-D-galacto-heptitol) with a sulfonyloxy group at the C-5 position. The synthesis of kotalanol itself was then achieved by coupling PMB-protected 4-thio-D-arabinitol with a cyclic sulfate that was synthesized from the naturally occurring D-perseitol. The work establishes unambiguously the structures of two natural products, namely, kotalanol and de-O-sulfonated kotalanol.
Four orders of magnitude rate increase in artificial enzyme-catalyzed aryl glycoside hydrolysis
Ortega-Caballero, Fernando,Bjerre, Jeannette,Laustsen, Line Skall,Bols, Mikael
, p. 7217 - 7226 (2007/10/03)
(6A6DR)-6A,6D-Di-C-cyano- β-cyclodextrin (1) and 6A,6D-di-C-cyano-α- cyclodextrin (2) were synthesized and shown to catalyze hydrolysis of aryl glycosides into glucose and phenol with a reaction following Michaelis-Menten kinetics. At pH 8.0 and 59 °C hydrolysis of 4-nitrophenyl α-glucopyranoside was catalyzed by 1 with KM = 10.5 ± 1.5 mM, kcat = 1.42(±0.09) × 10-4 s -1 and kcatk/uncat = 7922, Catalysis was observed with a concentration of 1 as low as 10 μM. Hydrolysis of the other aryl glycosides containing stereochemical variation in the sugar-moiety and 4-nitro-, 2-nitro-, 2-aldehydo-, and 2,4-dinitro- were also catalyzed by 1 and 2 with kcat/kuncat ranging from 4 to 7100. Hydrolysis of a phenyl β-D-glucoside or the thioglycoside tolylthio β-D-glucoside was also catalyzed. From a series of prepared analogues of 1 it was found that the catalysis was associated with the hydroxyl groups α to the nitril groups. The monocyanohydrin 6-C-cyano-β-cyclodextrin (3) was also found to catalyze the hydrolysis of 4-nitrophenyl β-glucopyranoside with k Cat/kuncat = 1356. It was proposed that the cyclodextrin cyanohydrins 1-3 catalyze the hydrolysis by general acid catalysis on the bound substrate.
Efficient synthesis of enantiopure conduritols by ring-closing metathesis
Jorgensen,Iversen,Paulsen,Madsen
, p. 4630 - 4634 (2007/10/03)
Two short synthetic approaches to enantiopure conduritols are described starting from the chiral pool. In both cases, the cyclohexene ring is assembled via ring-closing olefin metathesis. The terminal diene precursers for the metathesis reaction are prepared either from octitols or from tartaric acids. The former route involves a new method for selective bromination of the primary positions in long-chain carbohydrate polyols. Subsequent reductive elimination with zinc then generates the diene. The latter route uses a highly diastereoselective addition of divinylzinc to tartaric dialdehydes for preparation of the dienes.
THE SYNTHESIS OF SOME SEVEN-CARBON SUGARS via THE OSMYLATION OF OLEFINIC SUGARS
Brimacombe, John S.,Kabir, Abul K. M. S.
, p. 35 - 52 (2007/10/02)
The stereochemical outcome of the catalytic osmylation of 6,7-dideoxy-1,2:3,4-di-O-isopropylidene-α-D-galacto-hept-6-enopyranose (10), 5,6-dideoxy-1,2-O-isopropylidene-α-D-xylo-hex-5-enofuranose, (E)- and (Z)-3-O-benzyl-5,6-dideoxy-1,2-O-isopropylidene-α-D-xylo-hept-5-enofuranose (20 and 27, respectively), methyl (Z)-3-O-benzyl-5,6-dideoxy-1,2-O-isopropylidene-α-D-xylo-hept-5-enofuranuronate (26), (E)-3-O-benzyl-5,6-dideoxy-1,2-O-isopropylidene-α-D-ribo-hept-5-enofuranose, benzyl (E)- and (Z)-5,6-dideoxy-2,3-O-isopropylidene-α-D-lyxo-hept-5-enofuranoside (46 and 50, respectively), and methyluronate (49) has been examined.Such oxidations led to satisfactory syntheses of L-glycero-D-gluco-heptose and the corresponding heptitol (from 20), L-glycero-D-gulo-heptitol (from 26), D-glycero-D-gluco-heptitol (from 27), D-glycero-D-galacto-heptitol (from 10 and 46), (meso)-glycero-gulo-heptitol (from 49), and D-glycero-D-manno-heptitol (from 50).
