Synthesis of new N-substituted 3,4,5-trihydroxypiperidin-2-ones from d-ribono-1,4-lactone.

d-Ribono-1,4-lactone was treated with ethylamine in DMF to afford N-ethyl-d-ribonamide 8a in quantitative yield. Using this reaction procedure, N-butyl, N-hexyl, N-dodecyl, N-benzyl, N-(3-methyl-pyridinyl)-, N-(2-hydroxy-ethyl)-, and N-(2-cyano-ethyl)-d-ribonamides 8b-h were obtained in quantitative yield. Bromination of the amides 8a-e with acetyl bromide in dioxane followed by acetylation gave 2,3,4-tri-O-acetyl-5-bromo-5-deoxy-N-ethyl, N-butyl, N-hexyl, N-dodecyl, and N-benzyl-d-ribonamides 9a-e in 40-54% yields. To obtain 2,3,4-tri-O-acetyl-5-bromo-5-deoxy-N-(3-methyl-pyridinyl)-, N-(2-hydroxy-ethyl)-, and N-(2-cyano-ethyl)-9f-h, the bromination is necessary before the amidation reaction. Treatment of the bromoamides 9a-h with NaH in DMF followed by methanolysis affords N-alkyl-d-ribono-1,5-lactams 12a-h in quantitative yield.

Towards the synthesis of new benzimidazolone derivatives with surfactant properties.

New water-soluble benzimidazolone derivatives were synthesized. In the first approach, di-N-glycosyl and mono-N-alkyl-N-glycosyl compounds were obtained by grafting C-6-activated glycosides onto benzimidazolone. In the second approach, benzimidazolone derivatives bearing a glucosyl unit were synthesized using an efficient glycosylation method. Every compound structure was confirmed by means of NMR spectroscopy and elemental analysis. The preliminary surfactant properties of some compounds were evaluated.

A concise synthesis of 5-amino-5-deoxyaldonic acids as monomers for the preparation of nylon 5.

Saponification of 5-azido-5-deoxy-D-pentonolactones (ribo-, arabino-, xylo-) with NaOH gave the corresponding 5-azido-5-deoxyaldonic acids sodium salts which, after regeneration of the acid form followed by catalytic reduction, led to the target compounds in 98% overall yields.

Regioselective synthesis of 6-S-alkyl and 6-S-glycosyl-6-thio-D-mannofuranose derivatives from 5,6-O-cyclic sulfate precursors.

C-6 opening of 5,6-cyclic sulfate derivatives of mannofuranose with a thiolate anion followed by acidic hydrolysis of the acyclic sulfate gave 6-S-alkyl derivatives in good yields (70-95%) and short reaction times (10-15min). This methodology was applied to the synthesis of methyl 2,3-O-isopropylidene-6-S-(2,3,4,6-tetra-O-acetyl-beta-d-glucopyranosyl)-6-thio-alpha-d-mannofuranoside (70%), 2,3-O-isopropylidene-6-S-(2,3,4,6-tetra-O-acetyl-beta-d-glucopyranosyl)-6-thio-alpha-d-mannofuranose (87%) and 2,3-O-isopropylidene-6-S-(1,2:3,4-di-O-isopropylidene-alpha-d-galactopyranos-6-yl)-6-thio-alpha-d-mannofuranose (87%).

A novel stereospecific synthesis of glycosyl cyanides from 1,2-O-sulfinyl derivatives.

[reaction: see text] An efficient synthesis of 1,2-trans-glycosyl cyanides via 1,2-O-sulfinyl monosaccharides is described. Such S(N)2-type displacements at the anomeric center are stereospecific and are best performed with sodium cyanide in the presence of ytterbium triflate. Significantly, the resulting 1,2-trans-glycosyl cyanides have a free hydroxyl group at C-2 ready for further modification.

Direct syntheses of S-alkylthio-D-galactono-, D-mannono-1,4-lactones, S-alkylthio-L-galactitols and D-mannitols displaying amphiphilic and mesophasic properties.

Alkylthio-L-galactitols and D-mannitols were obtained in good yields (70-81%) by reduction, with NaBH4, of the corresponding 6-S-alkyl-6-thio-D-hexono-1,4-lactones.

Synthesis and amphiphilic properties of S-alkylthiopentonolactones and their pentitol derivatives.

The amphiphilic properties of S-alkylthiopentono-1,4-lactones (D-ribono-, D-arabinono-, D-xylono-) and corresponding pentitol derivatives with the general formula Su-SR (R=CnH2n+1) are studied. It was shown that CMC, surface area, CPP, and pC20 are influenced by the following structural parameters: alkyl chain length, the number of free hydroxyls, cyclic or acyclic Su structure, and alditol configuration.

Effect of phenolic glycosides on Agrobacterium tumefaciens virH gene induction and plant transformation.

O-Aryl-d-glucoside (4-7) and d-xyloside (8-10) derivatives were synthesized and tested on Agrobacterium virH gene induction and plant transformation. alpha- or beta-Glycosides enhanced vir activity at concentrations above 250 micromicro. The highest vir activity was observed with beta-glucoside derivative 4 at 10 mM. A marked difference between phenol glucoside derivative 4 and the corresponding free phenol on the growth of transformants was observed. The regenerated transgenic tissues, after transformation on medium containing acetosyringyl beta-glucoside 4, grew at twice the rate of those on medium containing only free acetosyringone (AS). Compound 4 was less toxic for tobacco explants compared to the corresponding free phenol. However, the xyloside derivatives tested (8-10) were less effective for gene induction compared with corresponding free phenols.

Efficient synthesis of 5-thio-D-arabinopyranose and 5-thio-D-xylopyranose from the corresponding D-pentono-1,4-lactones.

5-Thio-D-arabinopyranose (5) and 5-thio-D-xylopyranose (10) were synthesized from the corresponding D-pentono-1,4-lactones. After regioselective bromination at C-5, transformation into 5-S-acetyl-5-thio derivatives, reduction into lactols and deprotection afforded the title compounds in 49 and 42% overall yield, respectively.

An improved synthesis of 5-thio-D-ribose from D-ribono-1,4-lactone.

5-Thio-D-ribopyranose was synthesized from D-ribono-1,4-lactone (1) by two approaches: (i) 5-bromo-5-deoxy-D-ribono-1,4-lactone (2) was successively transformed into 5-bromo-5-deoxy, 5-S-acetyl-5-thio or 5-thiocyanato-D-ribofuranose derivatives; appropriate treatment then lead to 5-thio-D-ribopyranose (7) in 46-48% overall yield and; (ii) 2 was transformed into the 5-S-acetyl-5-thio-D-ribono-1,4-lactone derivative (11). Reduction and deprotection of 11 afforded 5-thio-D-ribopyranose (7) in 57% overall yield.