Showing papers on "Glucal published in 1969"
TL;DR: Tri-O-acetyl-D-glucal undergoes complete reaction with alcohols in benzene solution in the presence of boron trifluoride to give 4,6-di-OðOðAðEðDÞÞ −2,3-dideoxy-α-DÒÞ−EðE Þ−hex-hex-2-enopyranosyl as discussed by the authors, which can be used to prepare the known crystalline ethyl αglucoside easily and in greatly improved
Abstract: Tri-O-acetyl-D-glucal undergoes complete reaction with alcohols in benzene solution in the presence of boron trifluoride to give 4,6-di-O-acetyl-2,3-dideoxy-D-erythro-hex-2-enopyranosides. The α-anomers predominate (ca. 90%), and the method can be used to prepare the known crystalline ethyl α-glucoside easily and in greatly improved yield. Other alkyl glycosides have been prepared similarly, and the procedure has afforded means of obtaining the cholesteryl analogue and the disaccharide derivative 6-O-(4,6-di-O-acetyl-2,3-dideoxy-α-D-erythro-hex-2-enopyranosyl)-1,2:3,4-di-O-isopropylidene-α-D-galactopyranose. Tri-O-acetyl-D-glucal again gave the 2,3-unsaturated glycosides on treatment with acetals in the presence of boron trifluoride; no evidence was obtained for the formation of branched-chain products produced by additions to the double bond.
179 citations
TL;DR: On treatment with boron trifluoride-diethyl ether in benzene solution, tri-O-acetyl-D-glucal dimerises as discussed by the authors.
Abstract: On treatment with boron trifluoride–diethyl ether in benzene solution, tri-O-acetyl-D-glucal dimerises, and from the products the crystalline C–C linked disaccharide derivative 1,3,4,6-tetra-O-acetyl-2-C-(4,6-di-O-acetyl-2,3-dideoxy-α-D-erythro-hex-2-enopyranosyl)-2-deoxy-β-D-glucopyranose has been isolated. Dimerisation is believed to occur by the trans-addition of one molecule of 1,4,6-tri-O-acetyl-2,3-dideoxy-D-erythro-hex-2-enopyranose to the double bond of another, and in agreement with this, evidence has been obtained that tri-O-acetyl-D-glucal initially rearranges in the presence of the catalyst (or thermally) to give mainly the 2,3-unsaturated isomer.
31 citations
TL;DR: Chlorination of 3,4,6-tri- O -acetyl- d -glucal in daylight afforded 3, 4, 6-tri -O -2-chloro-2-deoxy-α-d-glucopyranosyl chloride (2) in the ratio ca. 4:1.
27 citations
TL;DR: The structure of 3,4,6-tri-O-acetyl-2,2-deoxy-2-iodo-α-d -mannosyl fluoride has been unequivocally established by X-ray analysis and has been confirmed by 19F magnetic resonance studies.
13 citations
TL;DR: In this paper, the reaction of chlorine with a suspension of D-glucal triacetate and silver monofluoride in an acetonitrile/benzene solution, affords a mixture of the four possible 2-chloro-2-deoxy-D-glycopyranosyl fluoride triacetates.
Abstract: Reaction of chlorine with a suspension of D-glucal triacetate and silver monofluoride in an acetonitrile/benzene solution, affords a mixture of the four possible 2-chloro-2-deoxy-D-glycopyranosyl fluoride triacetates. The structures of these derivatives have been established by nuclear magnetic resonance studies and confirmed by independent syntheses. The major product is 2-chloro-2-deoxy-β-D-glucopyranosyl fluoride triacetate. These results are compared with those from the related "BrF" and "IF" additions.
7 citations