Iodonium promoted reactions of disarmed thioglycosides

Konradsson, Peter; Udodong, Uko E.; Fraser‐Reid, Bert

doi:10.1016/s0040-4039(00)97609-3

Cited by 577 publications

(227 citation statements)

References 15 publications

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“…Manuscript in preparation). Briefly, a fully benzoylated galactofuranosyl thioglycoside was coupled with the appropriate acceptor alcohol under the promotion of N-iodosuccinimide and silver triflate (Konradsson, 1990). Subsequent deprotection of these products with sodium methoxide yielded the target molecules.…”

Section: Galactofuranose Derivativesmentioning

confidence: 99%

Nippostrongylus brasiliensis: Identification of intelectin-1 and -2 as Stat6-dependent genes expressed in lung and intestine during infection

Voehringer

Stanley

Cox

et al. 2007

Experimental Parasitology

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Elimination of the helminth parasite Nippostrongylus brasiliensis from infected mice is mediated by IL-4 or IL-13 and dependent on the IL-4Rα chain and the transcription factor Stat6 in nonhematopoietic cells. However, it is not clear which Stat6-dependent effector molecules mediate worm expulsion. We identified intelectin-1 and -2 as Stat6-dependent genes that are induced during infection. Intelectins can bind galactofuranose, a sugar present only in microorganisms and might therefore serve as microbial pattern element. To analyze whether constitutive expression of intelectin-1 or -2 leads to accelerated pathogen clearance, transgenic mice were generated which express high levels of these genes selectively in the lung. Infection with N. brasiliensis or Mycobacterium tuberculosis did not result in accelerated pathogen clearance in transgenic as compared to wild-type mice. Further, no significant modulation of the immune response in lung or lymph nodes was observed. Thus, under these conditions, intelectins did not enhance pathogen clearance.

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Section: Galactofuranose Derivativesmentioning

confidence: 99%

Nippostrongylus brasiliensis: Identification of intelectin-1 and -2 as Stat6-dependent genes expressed in lung and intestine during infection

Voehringer

Stanley

Cox

et al. 2007

Experimental Parasitology

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“…Further investigations using more biologically relevant acceptors, galactose diacetonide 5b and benzyl 2,6-di-O-benzyl-b-D-galactopyranoside 5c were performed with 1b. Thus, the reaction of 1b with 5b promoted by 3.0 molar equivalent of NIS and 3.0 molar equivalent of trifluoromethanesulfonic acid (TfOH) 18) in CH 3 CN at Ϫ40°C gave the corresponding a(2→6)-linked glycoside 6b in 60% yield stereoselectively (a/bϭ11 : 1, entry 2). The reaction of 1b with 5b did not proceed when the promoter was changed to AgOTf.…”

Section: Resultsmentioning

confidence: 99%

Preparation of 4-Pentenoic Acid Ester of Neu5Ac and 4-Pentenyl Glycoside of Neu5Ac and Their Application to Glycosylation

Ikeda

Fukuyo

Sato

et al. 2005

CHEMICAL & PHARMACEUTICAL BULLETIN

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N-Acetylneuraminic acids (Neu5Ac), sialic acids are most frequently found as a-glycosidically linked terminal residues of glycoproteins and glycolipids. There are a wide range of biological properties endowed by sialic acids on natural glycoconjugate structure and function, often involved in important cell surface communications and infection processes. 1-3)The development of the efficient method of O-sialylation has been a challenging task in the field of sialic acid chemistry. 4,5) Fraser-Reid and his co-workers introduced a 4-pentenyl group as a new and effective leaving group at the anomeric center of the glycosyl donor.6) The attractiveness of 4-pentenyl glycosides is enhanced by the fact that they can be applied to the armed/disarmed methodology of oligosaccharide synthesis.7) 4-Pentenyl glycosides are of interest for studying various biological and physiological phenomena of carbohydrates.8) To the best of our knowledge, there has been no report on the synthesis of 4-pentenoic acid ester of Neu5Ac (1a). A few reports 9,10) on the synthesis of 4-pentenyl glycoside of Neu5Ac (1b) have been reported, however application of 1b to O-sialylation has not been studied. As a part of our program aimed at the development of new O-sialylation, 11,12) we are interested in finding out whether 1a, b would be suitable for stereoselective O-sialylation. This paper describes the synthesis of 1a, b and their application to O-sialylation. Results and DiscussionWe first focused on an efficient synthesis of 1a having 4-pentenoyloxy group at the 2-position of Neu5Ac as a leaving group. Treatment of per-O-acetylated Neu5Ac 2 with hydrogen chloride in AcCl-AcOH (1 : 1) gave 2-chloro derivative 3 in a quantitative yield. Compound 3 was treated with silver carbonate in acetone-H 2 O (9 : 1) to afford 2-hydroxy derivative 4 13) in 88% yield. Acylation of 4 was achieved by 4-pentenoic anhydride and pyridine and N,N-dimethylaminopyridine (DMAP) in CH 2 Cl 2 to give 1a in a quantitative yield as an anomeric mixture with b-anomer as the major product (Chart 1). Next, we focused on a search for an efficient method of synthesizing 1b. When silver salicylate was used as a promoter in the presence of 4-penten-1-ol in CH 2 Cl 2 , 1b was obtained in 80% yield.9) The best result was obtained when the reaction was performed by Koenigs-Knorr condi- * To whom correspondence should be addressed. e-mail: ikeda@u-shizuoka-ken.ac. Novel sialosyl donors, 4-pentenoic acid ester of N-acetylneuraminic acids (Neu5Ac) (1a) and 4-pentenyl glycoside of Neu5Ac (1b) were successfully prepared from the corresponding per-O-acetylated 2-hydroxy and 2-chloro derivatives of Neu5Ac, respectively and applied to the synthesis of O-sialosides.

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“…The chitinase assay was performed according to the method previous reported. 3) S. 4, (6), and }, 4, (7). To a stirred suspension of thioglycoside 4 (198 mg, 0.22 mmol), demethylallosamizoline derivative 5 (84 mg, 0.22 mmol) and pulverized activated 4A molecular sieves (400 mg) in dry dichloromethane (S ml) was added N-iodosuccinimide (12S mg, 0.S6 mmol) at -15°C under Ar.…”

Section: Methodsmentioning

confidence: 99%

“…Thus, chitobiose derivative 4 3 ) and demethylallosamizoline derivative 52) were coupled by treating with Niodosuccinimide in the presence of trifluoromethanesulfonic acid and 4A molecular sieves in dichloromethane 6 ) at -lSoC to give pseudotrisaccharide 6 in a 73% yield together with glycal 7 3 ) (6% yield). In the lH-NMR spectrum of 6, H-C (1') resonated at S.44ppm as a doublet with J l '.2,=8.3Hz, typical of a 1,2-trans-configura ted glycosidic bond.…”

mentioning

confidence: 99%

Preparation of a Demethylallosamidin Isomer Having anN,N′-Diacetylchitobiosyl Moiety and Its Potent Inhibition against Yeast Chitinase

Takahashi¹,

Terayama²,

Kuzuhara³

et al. 1994

Bioscience, Biotechnology, and Biochemistry

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Iodonium promoted reactions of disarmed thioglycosides

Cited by 577 publications

References 15 publications

Nippostrongylus brasiliensis: Identification of intelectin-1 and -2 as Stat6-dependent genes expressed in lung and intestine during infection

Nippostrongylus brasiliensis: Identification of intelectin-1 and -2 as Stat6-dependent genes expressed in lung and intestine during infection

Preparation of 4-Pentenoic Acid Ester of Neu5Ac and 4-Pentenyl Glycoside of Neu5Ac and Their Application to Glycosylation

Preparation of a Demethylallosamidin Isomer Having anN,N′-Diacetylchitobiosyl Moiety and Its Potent Inhibition against Yeast Chitinase

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