Showing papers on "Glucal published in 2006"
TL;DR: A multi-gram epoxidation of 3,4,6-tri-O-benzyl-D-glucal and D-galactal with dimethyldioxirane with DMDO generated in situ from Oxone/acetone in a biphasic system resulted in the formation of the corresponding 1,2-anhydrosugars in a 99% yield and 100% selectivity.
56 citations
TL;DR: In this paper, the synthesis of 2,3-unsaturated α-d -glucosides by the S N 2′ addition of diverse aglycones onto 4,6-di-O -benzyl-3- O -propargyl glucal was achieved using a catalytic quantity of AuCl 3.
44 citations
TL;DR: A stereo-defined synthesis of two diastereomers of polyhydroxypyrrolidines from 3,4,6-tri-O-benzyl-d -glucal 4 involving a cleavage-recyclization strategy is reported in this article.
36 citations
TL;DR: In this paper, a p-(C-glucopyranosyl)-L-phenylalanine derivative protected to be directly incorporated into a peptidic chain is prepared in 37'% yield from glucose on a gram scale, with a Negishi cross-coupling reaction as the key step.
27 citations
TL;DR: In this article, triphenylphosphane hydrobromide was used as a catalyst for N-N bond formation in dichloromethane or THF, with the first use of HY zeolite to promote theFerrier rearrangement.
20 citations
TL;DR: Two new l-glucosamine donors, that is pent-4-enyl 3,4,6-tri- O -acetyl-2-allyloxycarbonylamino-2,deoxy-β- l -glucopyranoside 16 and ethyl 3.4, 6, 6-tri tri-O-acetyl 2,2-iodo-α-l -mannopyranoyl azide 8, were used for preparing l-Glucosamines neoglycolipids.
Abstract: Two new l -glucosamine donors, that is pent-4-enyl 3,4,6-tri- O -acetyl-2-allyloxycarbonylamino-2-deoxy-β- l -glucopyranoside 16 and ethyl 3,4,6-tri- O -acetyl-2-allyloxycarbonylamino-2-deoxy-1-thio-β- l -glucopyranoside 21 were prepared in 12 steps from l -arabinose. The reaction pathway uses 3,4,6-tri- O -acetyl- l -glucal 5 , and then 3,4,6-tri- O -acetyl-2-deoxy-2-iodo-α- l -mannopyranosyl azide 8 as intermediates. The latter, together with donors 16 and 21 , were used for preparing l -glucosamine neoglycolipids.
17 citations
TL;DR: A chiral carbohydrate ligand 3,4,6-tri-O-benzyl-d -glucal (L) reacts with the cluster triruthenium dodecacarbonyl Ru3(CO)12 giving a novel chiral cluster Ru3μ-H)2,CO)9(L-2H) (I) that shows fluxional behavior at room temperature as discussed by the authors.
13 citations
TL;DR: A variety of 2,3-unsaturated O-glycosides have been prepared by the Ferrier rearrangement of acetyl protected glycals under microwave irradiation using silica gel as an acid catalyst as discussed by the authors.
12 citations
TL;DR: The enzyme was found to be an effective catalyst to synthesize the beta-(1-->4) linkage of 2-deoxy-d-arabino-hexopyranoside.
8 citations
TL;DR: In this paper, 2-Deoxy carbohydrate carboxylic acids were prepared from glucal 4, acetobromoglucose 5, and D-galactose (7), respectively.
Abstract: 2-Deoxy carbohydrate carboxylic acids 1–3 were prepared from glucal 4, acetobromoglucose 5, and D-galactose (7), respectively. The acids 1–3 were electrolyzed with different coacids at controlled current in methanol at platinum electrodes in an undivided cell to afford C-glycosides as heterocoupling products in 46–70% yield. Compound 28, obtained by deacylation of 17, has a critical micelle concentration (cmc) of 2.4 mM, which is about 2.5 times lower than that of the corresponding O-glycoside 29. Compound 28 forms liquid crystals with a smectic A phase in the range between 96 and 190°C, which is twice as large as that of 29. Compounds 31 and 32, obtained by deprotection of 23 and 24, respectively, also exhibit liquid crystalline behavior.
7 citations
TL;DR: The 2-deoxy-2-iodo-d -glucose (2-DIG) was obtained from d-glucal and is a stable compound as discussed by the authors.
Patent•
19 Jul 2006
TL;DR: In this article, the disclosed preparation method for acetylized glucal comprises: preparing the D-acetylized glucose catalyzed by acids without separation or purification, leading directly the product into HBr or equivalent (such as PBr3 and water) to obtain and then recrystallize the coarse 1-bromoacetyl glucose with one of ethyl ether, propyl ether and isopropyl ether; adding Zn, ZnCl2, methanol and Co-ion catalyst to prepare the coarse target.
Abstract: The disclosed preparation method for acetylized glucal comprises: preparing the D-acetylized glucose catalyzed by acids (HClO4, H2SO4, ZnCl2, AlCl3, p-toluenesulfonic acid and methanesulfonic acid); without separation or purification, leading directly the product into HBr or equivalent (such as PBr3 and water) to obtain and then recrystallize the coarse 1-bromoacetyl glucose with one of ethyl ether, propyl ether and isopropyl ether; adding Zn, ZnCl2, methanol and Co-ion catalyst to prepare the coarse target; recrystallizing with alcohol for the refined product. This invention saves step and reduces cost.
TL;DR: In this paper, the synthesis of the δ-lactonic fragment of pironetin (1), a natural product with outstanding antimitotic properties, was reported, achieved from commercially available tri-O-acetyl-D-glucal (6) that was employed as starting material for the preparation of ethyl ketone 4, through a synthetic sequence that included a Ferrier rearrangement of 6 and suitable functional group manipulations of the resulting O−glycoside 7 to obtain the 4−ethyl glycoside 11, together with a series
TL;DR: The deacetylated polysaccharides obtained by polycondensation of 3,6-Di-O-acetyl- d -glucal followed by de acetylation proved to be a semicompetitive inhibitor of the human salivary amylase enzyme.
TL;DR: In this paper, the synthesis of the δ-lactonic fragment of pironetin (1), a natural product with outstanding antimitotic properties, was reported, achieved from commercially available tri-O-acetyl-D-glucal (6) that was employed as starting material for the preparation of ethyl ketone 4, through a synthetic sequence that included a Ferrier rearrangement of 6 and suitable functional group manipulations of the resulting O−glycoside 7 to obtain the 4−ethyl glycoside 11, together with a series
Abstract: The synthesis of the δ‐lactonic fragment of pironetin (1), a natural product with outstanding antimitotic properties, is reported. The synthesis was achieved from commercially available tri‐O‐acetyl‐D‐glucal (6) that was employed as starting material for the preparation of ethyl ketone 4, through a synthetic sequence that included a Ferrier rearrangement of 6 and suitable functional group manipulations of the resulting O‐glycoside 7 to obtain the 4‐ethyl glycoside 11, together with a series of 4‐C‐alkyl modified derivatives. The completion of the synthesis of 4 was performed via chain elongation at C‐6 by the introduction of a nitrile group and subsequent reduction, nucleophilic attack with ethyl magnesium bromide, and, finally, oxidation of the resulting alcohol 20.
TL;DR: A variety of 2,3-unsaturated O-glycosides have been prepared by the Ferrier rearrangement of acetyl protected glycals under microwave irradiation using silica gel as an acid catalyst.
Abstract: A variety of 2,3‐unsaturated‐O‐glycosides have been prepared by the Ferrier rearrangement of acetyl protected glycals under microwave irradiation using silica gel as an acid catalyst. Environmental friendliness, high yields, and short reaction times are the key features of this method. Furthermore, the method was applicable not only to the Ferrier reaction of 3,4,6‐tri‐O‐acetyl glucal and 3,4,6‐tri‐O‐acetyl galactal but also to the Ferrier reaction of 3,4‐di‐O‐acetyl arabinal.