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The attempted coupling of a carbohydrate ?-azido acid with a carbohydrate ?-amino ester in the presence of a diimide, hopefully to produce a dipeptide, yielded only the carboxylic anhydride. However, the combination of 4-toluenesulfonyl chloride in pyridine was successful, and four carbohydrate dipeptides were separately produced. One of these dipeptides was further transformed into a tripeptide, and another into a hexapeptide.  A single-crystal X-ray structure is reported for (3S)-3-azido-3-C-carboxy-3-deoxy-1,2:5,6-di-O-isopropylidene-?-d-ribo-hexose, amide with (3S)-3-amino-3-deoxy-1,2:5,6-di-O-isopropylidene-3-C-methoxycarbonyl-?-d-ribo-hexose.

Ethylene-N,N-bis(salicylideneiminato)oxovanadium(IV) {VO(salen)} has been developed as a useful catalyst for the reductive elimination of acylated glycosyl bromides to form glycals, both in the pyranose and furanose series, using zinc/ammonium chloride/methanol or zinc/acetic acid/acetonitrile.

A series of alkenyl ‘ β-D-C-glucopyranosides has been glycosylated with α-D-glucopyranosyl fluoride in a ‘Glycosynthase’ reaction to yield a range of alkenyl ‘ β-C-cellobiosides and -triosides and in one case a ‘ -C-cellotetraoside. Conversion of some of the alkenyl ‘ β -D-C-oligosaccharide products into their corresponding epoxides and subsequent deprotection under standard conditions have afforded a panel of epoxyalkyl ‘β -C-oligosaccharides for evaluation as inhibitors of retaining ‘ β-glycan hydrolases. Keywords: Glucopyranosides; oligosaccharides; epoxyalkyl oligosaccharides; ‘ β-glycan hydrolases.

Derivatives of 1,6-dideoxy-1,6-epithio-β-D-glucopyranose have been shown to undergo oxidation reactions to afford the corresponding sulfoxides and sulfones. The sulfoxides participate in Pummerer reactions to afford the corresponding α-acetoxy sulfides which were then oxidized further. None of the sulfoxides, sulfones or α-acetoxy sulfides prepared were particularly efficient glycosyl donors. Also presented are crystal structures of 1,6-dideoxy-1,6-epithio-β-D-glucopyranose S,S-dioxide and 1,6-dideoxy-1,6-episeleno-β-D-glucopyranose, interesting analogues of 1,6-anhydro-β-D-glucopyranose. Keywords. Episeleno; epithio; glucopyranose; oxidation; sulfoxides; sulfones; Pummerer reactions; X-ray crystal structures.

2,3-Epoxypropyl and 3,4-epoxybutyl 6′-deoxy-6′-iodo-β-cellobioside, together with 3,4-epoxybutyl 6′- deoxy-6′-fluoro-β-cellobioside, were prepared as putative inhibitors and reporter groups for events occurring at the active site of some β-glucan hydrolases. As well, related syntheses gave the previously unknown 6-deoxy-6-fluoro- and 6′-deoxy-6′-fluoro-cellobioses.

A glycosyl bromide derived from an Nlinked carba disaccharide has been converted into a phenyl thioglycoside and condensed with benzyl 2,3,6,2′,3′,6′-hexa-O-benzyl-β-cellobioside to give an N-linked carba tetrasaccharide. Complete removal of protecting groups then gave the 6′′-hydroxylated derivative of β-acarbose, coined ‘β-adiposin-2’, a putative inhibitor of enzymes that process β-D-glucosidic linkages.

Several new seleno- and telluro-β-D-glucopyranosides have been prepared by treatment of protected α-D- glucopyranosyl bromides with the appropriate dialkyl or diaryl dichalcogenide and sodium borohydride in ethanol.

The treatment of a 1-epivalienamine derivative with 1,6:3,4-dianhydro-2-O-benzyl-β-D-galactose has given an amino alcohol capable of conversion into either a cyclic carbamate or an aziridine. All attempts at acetolysis of the 1,6-anhydro ring of the cyclic carbamate failed owing to the inherent reactivity of the (allylic) benzyl ethers present in the molecule. Therefore, following a reduction with lithium in ammonia and acetylation of the product, a new cyclic carbamate was obtained which underwent successful acetolysis to provide a heptaacetate. This heptaacetate could be transformed into the desired methyl β-D-glucoside and base hydrolysis provided the 6-hydroxylated derivative of a diastereoisomer of methyl acarviosin, a putative inhibitor of enzymes which process β-D-glucosidic linkages.

Various carbohydrate triflates have been treated with cyclohexylamine and a 1-epivalienamine derivative to give some of the desired secondary amine, but mainly the product of a competing elimination reaction, namely a mixture of alkenes. When the reactions were conducted in the presence of potassium carbonate, novel carbohydrate carbamates were formed.

1,6:3,4-Dianhydro-2-O-benzyl-β-D-galactose has been treated with cyclohexylamine to give an amino alcohol, convertible into 2,3-di-O-acetyl-1,6-anhydro-4-cyclohexylamino-4-deoxy-β-D-glucose by reduction and acetylation. The anhydro bridge of this diacetate has been successfully opened under acetolysis conditions. The original amino alcohol has also been converted into a cyclic carbamate, a carbamate and an aziridine, by utilizing a variety of reagents and conditions. The 1,6-anhydro bridge of the cyclic carbamate, also containing a 2-O-benzyl ether, could be opened under acetolysis conditions but a comparable reaction was best done on the derived 2-O-acetyl compound. The resulting mixture of D-glucosyl acetates, still containing a cyclic carbamate, was convered into a methyl β-D-glucoside. The cyclic carbamate could be removed by hydrolysis with aqueous base to give a model glycoside for a synthesis of β-acarbose. Single-crystal X-ray structure determinations are reported for 2,3-di-O-acetyl-4-[acetyl(cyclohexyl)amino]-1,6-anhydro-4-deoxy-β-D-glucose, 1,6-anhydro-2-O-benzyl-3,4-[N-(cyclohexyl)epimino]-3,4-dideoxy-β-D-allose and methyl 2,6-di-O-acetyl-3,4-O,N-carbonyl-4-cyclohexylamino-4-deoxy-β-D-glucoside.

Three carbohydrate trifluoromethanesulfonates, of potential use in the alkylation of a 1-epivalienamine derivative to produce precursors of β-acarbose, have been prepared from the appropriate alcohols. The conversion of two of these trifluoromethanesulfonates into the primary amine, via the corresponding azide, is also reported.

The asymmetric dihydroxylation of various alkenyl tetra-O-acetyl- β-D-glucopyranosides has given mixtures of diols which, in one instance, has yielded a pure diastereoisomer upon recrystallization. This optically pure diol has been converted into an episulfide, a putative inhibitor of β-D-glucan hydrolases

An efficient synthesis of (R)-2,3-dihydroxypropyl 5-deoxy-5-dimethylarsinyl-β-D-riboside, a common marine arsenical, from D-ribose, (S)-2,3-dibenzyloxypropanol and iododimethylarsine is described.