M. H. Meshreki

New route for the synthesis of 3-deoxyaldos-2-uloses

Abstract 3-Deoxy- D - erythro - and 3-deoxy- D - threo -hexos-2-uloses, 3-deoxy- D - glycero -pentos-2-ulose, and 4-hydroxy-2-oxobutyraldehyde (“3-deoxytetros-2-ulose”) were obtained in about 20% net yields by heating aqueous solutions of D -glucose, D -galactose, D -xylose, and D -erythrose, respectively, with benzoylhydrazine and p -toluidine and decomposing the resultant 3-deoxyaldos-2-ulose bis(benzoylhydrazones) with benzaldehyde. Several 3-deoxyaldos-2-ulose bis(benzoylhydrazones) and p -substituted bis(benzoylhydrazones) are described for the first time.

Synthesis of triazole derivatives of sugars by 1,3-dipolar cycloaddition from acetylenic and azido precursors

Abstract 1,2,3-Triazoles having sugar chains at C-4, and others having the chain at N-1, were prepared. Condensation of 3- O -acetyl-4,5- O -isopropylidene-1-pentyne- D - threo -3,4,5-triol ( 1 ) with phenyl azide, followed by removal of substituents, gave 1-phenyl-4-( D - threo -trihydroxypropyl)-1,2,3-triazole ( 2 ), whose structure was proved by oxidation to known derivatives of 1-phenyl-1,2,3-triazole. The 1-benzyl analog ( 4 ) of 2 was prepared similarly. The 4- C -substituted 1,2,3-triazole 12 was obtained in the same way from the acetylenic sugar derivative 11. By condensing phenylacetylene with the sugar azides 13 (primary azide), 15 (secondary azide), and 17 (glycosyl azide), the 1-substituted 4-phenyl-1,2,3-triazoles 14, 16, and 18, respectively, were obtained. The 4-substituted 1-phenyl-1,2,3-triazoles and 1-substituted 4-phenyl-1,2,3-triazoles here reported show π→π* absorption near 246 nm, in contrast to the 4-substituted 2-phenyl-1,2,3-triazoles (phenylosotriazoles), which absorb near 268 nm. The optical rotatory dispersion spectrum of 2 shows a negative Cotton effect and is closely similar to that of the 2-phenyl analog ( D - threo -pentulose phenylosotriazole).

Synthesis of 2.3-unsaturated polysaccharides from amylose and xylan

Abstract Amylose ( 1 ) was tritylated at O -6, the ether p -toluenesulfonylated at O-2 and O-3, and the product ( 3 ) treated with sodium iodide and zinc dust in N,N -dimethyl-formamide, to give 2,3-dideoxy-6- O -trityl-α- D - erythro -hex-2-enopyranoglycan ( 4 ). This 2,3-unsaturated polysaccharide could be converted into a 2,3-dibromo derivative ( 5 ), and hydrogenated with concomitant detritylation to the saturated analogue ( 6 ), and, on treatment with aqueous acetic acid, it gave 2-( D - glycero -1,2-dihydroxyethyl)-furan ( 8 ). The 2,3-bis( p -toluenesulfonate) ( 10 ) of β- D -xylan ( 9 ) was similarly converted into the 2,3-unsaturated polysaccharide, 2,3-dideoxy-β- D - glycero -pent-2-enopyranoglycan ( 11 ), which, with aqueous acetic acid, gave 2-(hydroxymethyl)furan ( 12a ).

Bis(aroylhydrazones) of 3-deoxyaldos-2-uloses

Abstract The reaction whereby aldose or ketose precursors are converted in acidified aqueous ethanol in the presence of p -toluidine into 3-deoxyaldos-2-uloses and the latter are trapped as the crystalline bis(benzoylhydrazones) is shown to be of wide generality. Sugar precursors having four-, five-, six-, and seven-carbon chains, and aroylhydrazines having the p -toluoyl, p -anisoyl, p -chlorobenzoyl, p -iodobenzoyl, or p -nitrobenzoyl groups, all reacted to give the desired bis(aroylhydrazones) of the respective 3-deoxyaldos-2-uloses as crystalline products in a single operation. The u.v. and n.m.r. spectra of representative examples of the 31 compounds described have been examined.

Reactions of phenylglyoxal bisarylhydrazones

A number of phenyl-, and p-bromophenyl-glyoxal bisarylhydrazones were prepared. Their acetylation, benzoylation, and cyclisation to 2,4-diaryl-1,2,3-triazoles were investigated. The u.v. and i.r. absorption data of the compounds prepared are given.

Derivatives of osotriazoles and 4-formyl-2-phenyl-1,2,3-triazole

The benzylidene derivatives of D-xylose, D-arabinose, D-glucose, D-galactose, and L-sorbose phenylosotriazoles have been prepared in crystalline form. The pentose derivatives possessed one benzylidene residue, probably in the 4,5-positions, and the hexose derivatives possessed two benzylidene residues.

Linear polyaldehydes and polyalkenes derived from starch

Amylose (I) has been converted by photolysis of its 6-azido-6-deoxy-derivative (III) into a 6-aldehydo-analogue (IV) of amylose, and the 2,3-di-O-p-tolylsulphonly-6-O-trityl derivative (VII) of (I) has been converted into a 2,3-unsaturated polymer (VIII); the products (IV) and (VIII) may be useful for enzymic studies and as precursors for novel polyfunctional and crosslinked polymers.

Some 1-aryl 1,2,3-triazoles

A number of 1-aryl 1,2,3-triazoles have been synthesised; their u.v. absorption data and the apparent dissociation constants of the derived carboxylic acids are given. 1-Aryl 1,2,3-triazoles are nitrated and brominated in the 4-position of the phenyl ring.