Concise Synthesis of P-Glycosyl Alkenylphosphonates and P,C-di and P,P,C tri-Glycosyl Phosphonates

A direct access to P-glycosyl-, P, P-di-glycosyl alkenylphosphonates and P, C-glycosyl phosphonates is described. The method involves the Horner reaction of an anion derived from P-monoglycosyl and P ¹, P′-diglycosyl methylenediphosphonates either on the exocyclic aldehyde group of carbohydrates or on the masked aldehydic form of the furanose hemiacetals. In this last case, the carbonyl olefination, followed by an intramolecular cyclization, leads to P,C-di and P,P,C-triglycosyl phosphonates.     

Toward a novel series of furanopyrimidine nucleoside analogues

Based on an unusual furanose ring opening of 1,2-O-isopropylidene pentofuranoside derivatives, a preparation scheme of a new series of furanopyrimidine nucleoside analogues has been devised.     

单糖二级羟基的氧化及氧化剂的电化学行为

单糖二级羟基的氧化及氧化剂的电化学行为曹玲华,刘育亭（新疆大学化学系,乌鲁木齐,８３００４６）关键词吡喃糖,呋喃糖,氧化,氧化剂的电化学行为近年来,Ｃｏｒｅｙ等［１,２］研制的新试剂ＰＣＣ（Ｐｙｒｉｄｉｎｉｕｍｃｈｌｏｒｏｃｈｒｏｍａｔｅ）和ＰＤＣ（...     

Atomic-scale determination of DNA conformational response to strained furanose: a static mode approach

An original approach of macromolecular ‘induced-fit’ flexibility, namely the static modes, is applied to shed light on some fundamental mechanisms impacting DNA conformations. We first investigate a constrained nucleic acid of the D-CNA family, in which some backbone torsional angles are conformationally restricted by a dioxaphosphorinane ring structure. We take a special interest in α,β-D-CNA, in which α and β angles are restricted to the canonical conformation. We used the static mode method to evaluate the impact of the insertion of modified nucleotides on the stability of DNA/DNA and DNA/RNA duplexes. Although our approach authorizes the design of complex excitation modes on a specific molecule, we here establish with an atomic precision how a DNA south to north transition can be optimally operated through C5′ and O5′ single excitations.     

Complexation behavior of mono- and disaccharides by the vinylbenzeneboronic acid–divinylbenzene copolymer resins packed in a high-performance liquid chromatographic column

Using an HPLC column packed with monodispersed vinylbenzeneboronic acid–divinylbenzene (V–D) copolymer resins, the elution behaviors of the mono- and disaccharides were studied under different pH mobile phases. The monodispersed V–D copolymer resins were prepared by the copolymerization of 4-vinylbenzeneboronic acid and divinylbenzene in the presence of template silica gel particles (particle size: 5 μm; pore size: 10 nm), followed by dissolution of the template silica gel using a NaOH solution. Similarly, styrene–divinylbenzene (S–D) copolymer resins as the control resins were also synthesized. The transmission electron micrographs of these polymer resins revealed a good monodispersity. The complexation behavior of the saccharides was evaluated by comparison of the peak area eluted through the V–D column for that through the S–D column. Four aldopentoses (d-ribose, d-arabinose, d-xylose, and d-lyxose) and four aldohexoses (d-glucose, d-mannose, d-galactose, and d-talose) were retained completely at pH 11.9. Especially, ribose and talose were totally retained even under acidic and neutral conditions. For the disaccharides, unlike sucrose and maltose, palatinose was completely retained in basic mobile phases.     

Molecular structure of free canonical 2′-deoxyribonucleosides: a density functional study

The molecular structure of isolated canonical 2′-deoxyrinobucleosides was calculated using the density functional theory. It was demonstrated that the geometry of the base unit (BU) is almost unchanged compared to free nucleobases. Only slight out-of-plane deformation of the pyrimidine ring in deoxy-cytidine is observed. The conformation of the furanose ring strongly depends on the nature and orientation of the nucleobase. All nucleosides possess different conformations of this ring. Significant influence of the steric repulsion between the nucleobase and the sugar unit (SU) on puckering of the furanose ring and variation of the C–O and glycosyl bond lengths was demonstrated. The C(3′)-endo conformer of the furanose ring is more stable at the anti-orientation BU with respect to SU. An opposite trend is observed for the syn-orientation which is additionally stabilized by an intramolecular hydrogen bond with participation of the C(5′)OH group.