Polymers from sugars and CS2: ring opening copolymerisation of a ᴅ-xylose anhydrosugar oxetane

A ᴅ-xylose anhydro sugar derivative (1) has been applied in ring-opening copolymerisation (ROCOP) with CS2 to form a polythiocarbonate (poly(CS2-co-1)) with high head-head/tail-tail regioselectivity towards alternating thiono- and trithiocarbonate linkages...

Chemo-enzymatic Synthesis of 3′-azido/-amino-C-4′-spirooxetano-xylo nucleosides

Conformationally locked 3'-azido-C-4'-spirooxetano-xylonucleosides T, U, C and A have been synthesized by following chemo-enzymatic convergent route. One of the 3'-azido-C-4'- spirooxetano-xylonucleosides, i.e. T was converted into 3'-amino-C-4'-spirooxetano-xylothymidine by reduction of azide to amine with H2/Pd-C in ethyl acetate in quantitative yield. The crucial step in the synthesis of spirooxetano-xylonucleosides is the Lipozyme® TL IM-mediated exclusive diastereoselective acetylation of 4-C-hydroxymethyl group in dihydroxysugar derivative, 3-azido-3-deoxy-4-Chydroxymethyl- 1,2-O-isopropylidene-α-D-xylofuranose in quantitative yield. The diastereoselective monoacetylation of 4-C-hydroxymethyl in dihydroxysugar derivative was unambiguously confirmed by X-ray crystal study on the tosylated compound obtained by the tosylation of Lipozyme® TL IM - mediated monoacetylated sugar derivative. The broader substrate specificity and exclusive selective nature of Lipozyme® TL IM can be utilised for the development of environmentally friendly methodologies for the synthesis of different sugar-modified nucleosides of importance.

Identification of Two Arabidopsis thaliana Plasma Membrane Transporters Able to Transport Glucose 1-Phosphate

Primary carbohydrate metabolism in plants includes several sugar and sugar-derivative transport processes. Over recent years, evidences have shown that in starch-related transport processes, in addition to glucose 6-phosphate, maltose, glucose and triose-phosphates, glucose 1-phosphate also plays a role and thereby increases the possible fluxes of sugar metabolites in planta. In this study, we report the characterization of two highly similar transporters, At1g34020 and At4g09810, in Arabidopsis thaliana, which allow the import of glucose 1-phosphate through the plasma membrane. Both transporters were expressed in yeast and were biochemically analyzed to reveal an antiport of glucose 1-phosphate/phosphate. Furthermore, we showed that the apoplast of Arabidopsis leaves contained glucose 1-phosphate and that the corresponding mutant of these transporters had higher glucose 1-phosphate amounts in the apoplast and alterations in starch and starch-related metabolism.

Hydrogen bonding-induced conformational change in a crystalline sugar derivative

We report crystallographic evidence of the change of a regular chair conformation to a skew boat conformation in a partially protected sugar derivative.

Synthesis, Characterization, and Thermokinetic Analysis of New Epoxy Sugar Derivative

The synthesis of 5,6-O-isopropylidene-1,2-O-(R)-trichloroethylidene-α-D-glucofuranose (compound1) and 5,6-O-isopropylidene-1,2-O-(R)-trichloroethylidene-3-O-(2′,3′-epoxypropan-1′-yl)-α-D-glucofuranose (compound2) was carried out. The synthesized compounds1and2were characterized by nuclear magnetic resonance (1H-NMR), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TG). The FTIR and1H NMR spectra showed that the epoxy group in compound2was attached by means of a nucleophilic substitution reaction. The activation energies for thermal degradation of compounds1and2were calculated from their TG data by using the Kissinger-Akahira-Sunose (KAS) and Tang methods.