Significant rate accelerated synthesis of glycosyl azides and glycosyl 1,2,3-triazole conjugates

Abstract

An efficient and significantly rapid access of a series of glycosyl azides and glycosyl 1,2,3-triazole conjugates is reported using modified one-pot reaction conditions. In both cases yields were excellent and single diastereomers were obtained.

Synthesis of esters derived from 2,3,4,6-tetra-O-acetyl-1-[4-(2-hydroxyethyl)-1H-1,2,3-triazol-1-yl]-β-D-glucopyranose

“…The reaction of 2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl azide (prepared in situ from α-acetobromoglucose (α-ABG) upon reaction with NaN3 in DMSO) [29] with but-3-yn-1-ol alcohol under click chemistry conditions [29,30] afforded the alcohol (1) with an overall yield of 47%. The presence of a singlet at 8.13 ppm for the H-5 of the triazole ring, as well as the expected signals for CH2CH2OH confirms the structure of the alcohol.…”

Synthesis of β-Glycosyl Amides from N-Glycosyl Dinitrobenzenesulfonamides

“…Initially we began by selecting d -glucose and d -galactose and converting each into the corresponding β-glycosyl azide 1 and 2 , respectively. 27 Reduction of glycosyl azides was accomplished using Adams’ catalyst to generate the respective glycosylamines. As free glycosylamines are prone to anomerization, the reduced glycosylamine was immediately subjected to sulfonation with dNBS-Cl in pyridine.…”

Four-component one-pot synthesis of a branched manno-pentasaccharide: tert-butyldiphenylsilyl ether as an in situ removable carbohydrate-protecting group

“…Building blocks 2 and 3 were prepared by literature 8,9 procedures and synthetic strategy of the building blocks 4 and 5 starting from phenyl thioglycoside 10 (7) and benzyl mannopyranoside 11 (10), respectively, are described in Scheme 2. The structures of all new products were well supported by spectroscopic and analytical data.…”

“…Phenyl thioglycoside 7 first treated with triethylorthoacetate in presence of camphorsulfonic acid (CSA) as catalyst produced 2,3:4,6-di-O-orthoester, in situ ring opening of which gave 2,4-and 2,6-acyl protected thioglycosides nearly in 1:1 ratio. 12 Selective acetylation of the primary hydroxyl 13 in presence of secondary hydroxyl groups was then carried out by treating the mixture with acetyl chloride in pyridine at À40 C to produce triacetylated phenyl thiomannopyranoside (8) in 30% overall yield after flash chromatography. Coupling of trichloroacetimidate donor 14 (9) with acceptor 8 was achieved by chemoselective activation of the former by TMSOTf 15 in CH 2 Cl 2 at À20 C to produce compound 4 in 85% yield.…”

“…1 H and 13 C NMR spectra were recorded in Bruker DPX 300/600 MHz and Bruker DPX 75/150 MHz spectrometer, respectively, using tetramethylsilane (d¼0.00) as an internal standard at 25 C. ESI-MS (positive) was conducted using LC-ESI-Q-TOF micro Mass spectrometer. (8). To a solution of compound 7 (0.1 g, 0.37 mmol) in DMF (2 ml) trimethylorthoacetate (0.01 ml, 0.81 mmol) and p-TsOH (10 mg) were added.…”