Topic
Glycal
About: Glycal is a research topic. Over the lifetime, 897 publications have been published within this topic receiving 17422 citations.
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TL;DR: In this article, the synthesis of 4,6-di-O-acetyl-2-deoxy 2-fluoro-β-glycosyl fluorides is described.
Abstract: The synthesis of 4,6-di-O-acetyl-2-deoxy-2-fluoro-3-O-(tetra-O-acetyl-β-d-glucopyranosyl)-β-d-glucosyl fluoride is described. Upon deacetylation and treatment with α-d-glucopyranosyl fluoride in the presence of a glycosynthase, three products, all 2-deoxy-2-fluoro-β-glycosyl fluorides, could be isolated: a trisaccharide, a tetrasaccharide, and a pentasaccharide. An attempt to convert a trisaccharide glycal into a related difluoride, employing Selectfluor, is also reported.
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TL;DR: The 1,3-diaza-2-azoniaallene salt 3a reacts stereoselectively with glycals (5a,b) to afford pyrano[2, 3-d]-1, 2, 3 -triazolium salts as discussed by the authors.
Abstract: The 1,3-diaza-2-azoniaallene salt 3a reacts stereoselectively with glycals (5a—e) to afford pyrano[2,3-d]-1,2,3- triazolium salts 6a—e. In contrast to other 1,3-dipolar cycloadditions of glycals reported so far, the stereoselectivity of compounds 6 is not determined by the substituent on C-3 of the glycal. Both cis (6a,b) and trans (6d,e) substitutions on C-7 and C-7a were found for bicyclic compounds 6 (crystal structure of 6a). Under the influence of acid 6e opens the pyran ring to give the triazolium salt 9. Addition of antimony pentachloride to a solution of the glycal 5e and the chlorotriazene 2a results in the formation of the pyranotriazene 12 containing two triazene units. In the presence of acid the pyranotriazene 6c reacts with alcohols to afford 2-hydrazino glycosides 13a,b, 15, which with zinc dust in acetic acid are reduced to 2-amino glycosides 14a,b.
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TL;DR: A review of 1,2-cyclopropyl car-bohydrates can be found in this paper, where a wide variety of products are obtained depending on the functionality attached to the cyclopropane and the promoter (Lewis acid, Br o nsted acid, halophile or base).
Abstract: Addition of a carbene to a glycal is the prominent method for the synthesis of 1,2-cyclopropyl car- bohydrates. This incorporation of a cyclopropane into a carbohydrate scaffold enables divergent reactivity, with the two main classes being ring expansion and cleavage to 2- C -branched carbohydrates. A wide variety of products are obtained depending on the functionality attached to the cyclopropane (none or ester or hal- ogens) and the promoter (Lewis acid, Br o nsted acid, halophile or base) used in the reaction. This article reviews progress in the synthesis and reactions of 1,2-cyclopropyl carbohydrates since 2000 and discloses efforts by our group in the area.
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04 May 1988
TL;DR: In this paper, the application of these analogues in the preparation of new glycal, anthracycline obtained using these glycal and the use of said glycal as medicaments glycals are obtained from L-fucose and /or its analogues of formula 1 ': (CF DRAWING iN BOPI) and of the formula 2 below.
Abstract: This invention relates to new analogues of L-fucose, to their preparation process, the application of these analogues in the preparation of new glycal, anthracycline obtained using these glycal and the . using said anthracyclines as medicaments glycals are obtained from L-fucose and / or its analogues of formula 1 ': (CF DRAWING iN BOPI) and of the formula 2 below: (CF DRAWING iN BOPI) wherein: R represents an optionally substituted alkyl group, linear or branched or a group optionally substituted aryl, with the exception of a hydrogen atom, a group CH2 OH or CH2 OR3 group, R3 having the same meaning as R.