Cellulose (7% water) was thoroughly dispersed in various ionic liquids (IL) and the turbidity of the mixture was investigated to distinguish real dissolution from fine dispersion. The dissolving ability of 1-butyl-3-methylimidazolium chloride (BMIMCl know cellulose solvent) and 11 other commercial IL (not reported as cellulose solvents) was studied. From the latter, only 1,3-dimethylimidazolium dimethylphosphate (DMIMDMP) could dissolve cellulose. The influence of water content on the real dissolution of cellulose in these two IL was investigated. The maximum theoretical amount of dissolved anhydrous cellulose in the IL was determined by extrapolation methodology at different temperatures. For cellulose in BMIMCl, it was 8.75 g/100 g of IL at 95°C. DMIMDMP could achieve real cellulose dissolution only in a practically anhydrous system (2.3 g/100 g of IL at 30°C) but dissolution was physically limited by high viscosity.

P‐CNAs are dinucleotide building blocks in which the torsional angles α and β of the sugar/phosphate backbone are constrained to non‐canonical values within a cyclic phosphonate structure (phostone) synthesised by diastereoselective intramolecular Arbuzov reaction. The reaction has been improved through the use of microwave activation and addition of lithium bromide.

With increasing interest in the control of the conformations of nucleic acids to define active riboswitch or siRNA, we present herein our efforts towards the stereocontrolled synthesis and conformational analysis of ribodinucleotides in which α and β torsional angles are constrained within a dioxaphosphorinane structure (ribo‐α,β‐D‐CNA). The crystal structure analysis of one α,β‐D‐CNA TU dimer demonstrates the absolute stereochemistry of the newly created asymmetric centres. NMR and CD analyses allowed complete assignment and the determination of the torsional angles in the α,β‐D‐CNA UU diastereoisomers.

We describe a rational approach devoted to modulate the sugar-phosphate backbone geometry of nucleic acids. Constraints were generated by connecting one oxygen of the phosphate group to a carbon of the sugar moiety. The so-called dioxaphosphorinane rings were introduced at key positions along the sugar-phosphate backbone allowing the control of the six-torsion angles α to ζ defining the polymer structure. The syntheses of all the members of the D-CNA family are described, and we emphasize the effect on secondary structure stabilization of a couple of diastereoisomers of α,β-D-CNA exhibiting wether B-type canonical values or not.