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Novel isoxazoline and pyrazoline derivatives of N-substituted saccharin were synthesized in good yields by 1,3-dipolar cycloaddition of N-crotonoyl- or N-cinnamoylsaccharin as dipolarophile to arylnitrile oxides or nitrile imines using p-HAP300 as catalyst under solventfree microwave conditions. In this process, the yields were significantly improved compared to classical conditions without alteration of the selectivity. The regioselectivity as well as the nonthermal specific microwave effect are discussed.

An inexpensive, simple, and highly efficient process is developed for the selective anomeric azidation of protected sugars using ultrasound activation and an of iron catalyst.

An efficient and eco-friendly three-step one-pot procedure for the synthesis of a new series of glycosyl triazoles is developed using ultrasonic activation and iron-copper dual catalysis.

This review, divided into three sections, describes the contribution of the chemists’ community to the development and application of triple helix strategy by using artificial nucleic acids, particularly for the recognition of DNA sequences incorporating base pair inversions. Firstly, the development of nucleobases that recognise CG inversion is surveyed followed secondly by specific recognition of TA inverted base pair. Finally, we point out in the last section recent perspectives and applications, driven from knowledge in nucleic acids interactions, in the growing field of nanotechnology and supramolecular chemistry at the border area of physics, chemistry and molecular biology.

N-Azolyl olefins undergo a cohalogenation reaction when treated by the NBS/ROH system to give novel N-(bromoalkoxypropane) azolyl derivatives.

The coupling of gem-chloro-nitro derivatives as substrates for S RN 1 reactions with anions derived from variously substituted β-dicarbonyl compounds readily gives key compounds which, depending upon the structure of the reactants, lead directly to functionalized olefins, or under acidic treatment to butenolides and to simple or spiro-β-nitro-γ-butyrolactones

Base-promoted fragmentation of products resulting from S RN 1 reactions between gem halonitro alkanes and cyclanone β-esters as nucleophiles gives rise to di- or trifunctionalized olefins. These olefins carry a chain whose length is determined by the size of the ring in the cyclic nucleophile

Two new and versatile synthetic methods for preparing 5-nitro-analogues of HEPT and MKC-442 which are HIV-1 reverse transcriptase inhibitors, are reported. In both cases the key-step is based upon the displacement of a 6-methylthio or a 6-tosyl group by nucleophiles according an addition-elimination type mechanism.

Phosphoramidites 6a-c were readily prepared by an original route and used to incorporate serinol derived units I–III in oligonucleotides which, compared to their natural analogues, exhibited a decreased htbridization capacity for duplex and triplex formation.

Herein is described a mild and effective iodination method using bis-(trifluoroacetoxy)iodobenzene-iodine as reagent to be applied to electron deficient heterocyclic systems (protected indoles, coumarin…) Moreover, sensitive protecting groups such as acetyl and tert-butyldimethylsilyl were found to be stable under the new iodination reaction conditions.

We have studied the stereoselective synthesis of new C-nucleosides by heteroarylation of the protected γ-ribonolactone by means of heteroaromatic systems such as indole, thiazoles, imidazoles and benzimidazoles. We have observed that the first anion addition-limiting step is very sensitive to steric factors induced by the N-protective groups in α-position.

Several 6-allyl and 6-heteroarylindoles have been synthesized in high yield by means of palladium catalyzed cross-coupling reactions between tributyltin derivatives and 6-haloindoles to give useful intermediates for the synthesis of analogues of biologically active natural products.

Thermal denaturation experiments have established that an oligonucleotide incorporating the artificial nucleobase S, does form a stable triplex with a double stranded DNA which exhibits a pyrimidine interruption within the oligopurine sequence.

Thieno analogues of the potent and selective furo-pyrimidine anti-VZV nucleoside family are herein reported. The compounds retain full antiviral potency in comparison to the furo parent. Thieno analogues of the potent and selective furo-pyrimidine anti-VZV nucleoside family are herein reported. The compounds retain full antiviral potency in comparison to the furo parent.

The synthesis of monoglycosyl imidazoles and 1,1′-di- O -glycosides is described by direct glycosylation process from reducing sugar in the presence of 1,1′-thiocarbonyldiimidazole. Novel anomeric groups as 1- O -(imidazolyl)thiocarbonyl and 1- O -(imidazolyl)carbonyl are presented as potent glycosidic activators.

We report herein a short stereocontrolled synthesis of heterocyclic C-nucleosides (indole, imidazole, benzimidazole, and 6-iodobenzimidazole). First, condensation of 2-lithiated heterocycles 2−5 wi...

t: A one-pot, three-component approach to a new family of 4,5-functionalized triazolyl-nucleosides is described. The method relies on the one-pot azide-alkyne 1,3-cycloaddition/electrophilic addition tandem reaction, which affords good yields of the corresponding 4,5-disubstituted nucleosides.

A simple, efficient and eco-friendly procedure has been developed for the aromatisation of various pyrazolines in heterogeneous media using clay-supported copper(II) nitrate (claycop) under ultrasound activation. The reaction rate enhancement and the sonication effect are discussed.

A short route to novel α-(2-aminothiazolyl)-C-nucleosides has been developed. The key step was the high diastereoselective reduction of the hemiacetal intermediates using L-Selectride, which afforded the corresponding R -diols in quantitative yields. These diols were converted, after C4–C1 ring closure and protecting groups cleavage, to their corresponding free α-C-nucleosides.

We report herein the synthesis of β-2-benzimidazolyl- and β-2-indolyl- C -nucleosides and their α-anomers in a stereoselective way. The stereocontrol was observed either in the reduction step (hemiacetal to diol) of the protected heterocycles ( 1b – d ), or in the intramolecular Mitsunobu cyclisation of the free heterocyclic diols obtained from the hemiacetals 1a and 1e .

A short route to pyrimidine locked nucleosides has been developed for their incorporation in triplex forming oligonucleotides (TFO). Compared to oligonucleotides built with standard nucleosides, the modified TFOs containing 3'-endo blocked residues formed, with their corresponding DNA duplexes, more stable triple helix systems, an effect which might be ascribed to the 3'-endo pucker of the modified nucleoside residues.