R. H. Furneaux

Synthesis of 1,2-trans-related 1-thioglycoside esters

Boron trifluoride etherate catalyses the condensation of equimolar proportions of 1,2-trans-related monosaccharide peresters and thiols to provide a convenient synthesis of esters of 1,2-trans-1-thioglycosides. The reaction is efficient with alkyl, alkenyl, and some aryl thiols, and with aldopentose, aldohexose, and hexuronic acid acetates and benzoates. Some limitations are noted.

Observations on the possible application of glycosyl disulphides, sulphenic esters, and sulphones in the synthesis of glycosides

Abstract Partial desulphuration of tetra-O-acetyl-β- d -glucopyranosyl phenyl disulphide with a phosphine derivative gave 40% of phenyl 2,3,4,6-tetra-O-acetyl-1-thio-α- d - glucopyranoside and a similar proportion of β- d -glucopyranosyl 1-thio-α- d -glucopyranoside octa-acetate, showing that this procedure is of limited value in α- d -thio-glucoside synthesis. Similar treatment of allyl tetra-O-acetyl-,β- d -glucopyranosyl sulphoxide caused abstraction of oxygen, rather than of sulphur, from the derived allyl glucosylsulphenate. The phenylsulphonyl group was not readily displaced from β- d -glucopyranosyl phenyl sulphone, except intramolecularly, nor could it be displaced from the tetrabenzyl ether. Elimination of benzyl alcohol from this compound afforded a new 1-(phenylsulphonyl)glycal derivative.

Syntheses of the fungicide/insecticide allosamidin and a structural isomer

A synthesis of the naturally occurring inhibitor of chitin metabolism, allosamidin 1, involves, as the key step, condensation between the allosamizoline derivative 39, prepared following oxyamination of the cyclopentene 19, and the disaccharide glycosylating agent 54 which was synthesised from 2-acetamido-2-deoxy-D-glucose. The structural isomer 59 of allosamidin is also reported. Brief biological test results obtained using isomers 1 and 59 are recorded.

The chemistry of some 1-mercury(II)thio-d-glucose compounds; a new synthesis of 1-thio sugars

Abstract Treatment of tetra-O-acetyl-β- d -glucopyranosyl N,N-dimethyldithiocarbamate (1) with phenylmercury(II) acetate gives tetra-O-acetyl-1-phenylmercury(II)thio-β- d -glucopyranose (3), which can also be made in high yield from other dithiocarbamates, from tetra-O-acetyl-1-thio-β- d -glucopyranose, and from its S-acetyl derivative. The p-diethylamino derivative (7) of compound 3 displays significantly different properties and is readily convertible into bis(tetra-O-acetyl-1-thio-β- d -glucopyranosyl)mercury(II) (8), which is also obtainable by treatment of tetra-O-acetyl-1-thio-β- d -glucopyranose with mercury(II) acetate. Aspects of the chemistry of compounds 3, 7, and 8 are reported; demercuration of 3 affords a convenient synthesis of 2,3,4,6-tetra-O-acetyl-1-thio-β- d -glucose.

A new route to L-ascorbic acid (vitamin C)

Photochemical bromination of methyl tri-O-acetyl-2,6-anhydro-L-gulonate (2) with N-bromosuccinimide gives methyl tri-O-acetyl-α-L-xylo-hexulopyranosylonate bromide (5) which, on acetoxylation and hydrolysis, provides a further synthetic route to L-ascorbic acid.

Making Human Milk Oligosaccharides Available for Research and Application – Approaches, Challenges, and Future Opportunities

Elucidation of the biological roles and more detailed structure–function relationships of human milk oligosaccharides (HMOs) requires access to homogeneous, defined HMO samples. Various approaches, including chemical synthesis, enzymatic/chemoenzymatic synthesis, and fermentation processes, have been developed to support this goal. Examples of scalable industrial processes demonstrating each approach are presented. These strategies, alone and in combination, may be deployed to address the problem of routine access to HMOs for biological and nutritional research and applications.