This study focuses on the preparation of some 1-alkynyl-2-deoxy-D-riboses and their application to the generation of C-nucleosides analogues Examples are provided in which the alkyne functionality took part in allkylation or cycloaddition reactions A discussion of the protecting group used is provided (C) 2010 Elsevier Ltd All rights reserved

Herein, we describe a short synthesis of 3-methyl-4-nitro-5-alkylethenyl isoxazoles and their reactivity as Michael acceptors. The title compounds reacted with nitromethane under phase-transfer catalysis to provide highly enantioenriched adducts (up to 93% ee) which were then converted to the corresponding gamma-nitroacids.

The reaction between 3-methyl-4-nitro-5-styrylisoxazoles and ethyl isocyanoacetate proceeded under phase transfer catalysis to give enantioenriched monoadducts in high enantiomeric excess (up to 99% ee). The resulting adducts were subsequently cyclised to give 2,3-dihydropyrroles and substituted pyrrolidines in identical high ees and as a single diastereoisomer.

(Z)-3-Substituted-2-(4-pyridyl)-acrylonitriles, a reactive class of Michael acceptors obtained exclusively as a single (Z) isomer, reacted with un-substituted isocyanoacetate esters mediated by phase-transfer catalysis to give, after base promoted cyclisation, functionalized imines in up to 94% ee and as a single diastereoisomer.

Heavily substituted cyclopropane esters were prepared in high yields, complete diastereoselection and average (up to 58%) enantioselectivity. The reaction described herein entailed reacting 4-nitro-5-bromostyrylisoxazoles, a class of powerful Michael acceptors with malonate esters under the catalysis of 5 mol% of a chincona derived phase-transfer catalyst.

Herein is reported the development of a new process to manufacture (S)-pregabalin. The method comprises six steps, run under the catalysis of a recyclable polymer bound phase transfer catalyst, and afforded (S)-pregabalin in overall 54% yield, starting from building blocks acetylacetone, isovaleraldehyde, and nitromethane.

Functionalised medium-sized ether rings were prepared in an efficient manner by [4+3] cycloaddition followed by ring-opening metathesis. This procedure provided medium-sized rings, which were shown to be useful for the assembly of fused bicyclic structures present in complex natural compounds. The potential of the chemistry described in this paper to be used in synthesis has been demonstrated by the preparation of functionalised large cyclic ethers and bicyclic structures.

Heavily substituted cyclopropane esters were prepared in high yields, complete diastereoselection and high (up to 96%) enantioselectivity. The reaction described herein entailed reacting 4-nitro-5-styrylisoxazoles, a class of cinnamate synthetic equivalent, with 2-bromomalonate esters under the catalysis of 5 mol% of a Cincona derived phase-transfer catalyst. The reaction allowed multi-gram preparation of desired products.

Herein, we report our investigation into the reactivity of 5-enamino-4-nitroisoxazoles. This study revealed that the title compounds, in spite of conjugation to the 4-nitroisoxazole, displayed similar reactivity to enamines, reacting with electrophiles to form new C-C, C-N, and C-Cl bonds. (C) 2015 Elsevier Ltd. All rights reserved.

In recent times, several efforts have been devoted to develop new synthetic methodologies to access active the pharmaceutical ingredient (S)-Pregabalin. Marketed as (LyricaTM), (S)-Pregabalin is indicated for the treatment of epilepsy, neuropatic pain and anxiety. As presented in this short review, the methodologies available to prepare (S)-Pregabalin can be classified by the method employed to install the desired absolute stereochemistry, namely: (a) preparation of Pregabalin as a racemate and its resolution; (b) enantioselective syntheses; (c) processes involving a biocatalytic step. This review provides an overview of the state of the art on the synthetic methodology available to prepare this blockbuster API.

We have investigated the reactivity of 3-methyl-4-nitro-5-styrylisoxazoles with S-nucleophiles. This study revealed that the title compounds were optimal Michael acceptors toward thiols. A procedure was also established to prepare isoxazole-containing sulfides in one-pot and without the use of chromatography. Isoxazole-containing sulfides were converted into the corresponding sulfones in high yield. (C) 2011 Elsevier Ltd. All rights reserved.

A novel nucleic acid compaction device based on a positivelychargedalpha,epsilonpolyllysinewasrealized for the first time. The polycationic peptide was obtained by assembling Fmoc and Boc orthogonallyprotected llysinemonomers by solid phase synthesis. The route to the novel polycation is veryfast and convenient because it allows for the obtainment of the desired product in few synthetic stepsexclusively employing Fmoc chemistry. The purification of the polyaminoacid was performed easilyby RPHPLCon C18 stationary phase while ESIMSanalysis confirmed the identity of the novel basicmolecule. The structural characteristics of the novel watersolublepeptide, as well as the interaction withdeoxyribonucleic acid (DNA) and ribonucleic acid (RNA) have been investigated by circular dichroism (CD)and ultraviolet (UV) spectroscopy.

We report the first synthetic route to prepare 3-methyl-4-nitro-5-(2-alkylethenyl)isoxazoles in high yields and as E-diastereoisomers. (C) 2014 Elsevier Ltd. All rights reserved.