Synthèse de l'apiose et de composés voisins par des réactions de wittig

Nucleosides with Transposed Base or 4'-Hydroxymethyl Moieties and Their Corresponding Oligonucleotides

This review focuses on 4'-hydroxymethyl- or nucleobase-transposed nucleosides, nucleotides, and nucleoside phosphonates, their stereoisomers, and their close analogues. The biological activities of all known 4'-hydroxymethyl- or nucleobase-transposed nucleosides, nucleotides, and nucleoside phosphonates as potential antiviral or anticancer agents are compiled. The routes that have been taken for the chemical synthesis of such nucleoside derivatives are described, with special attention to the innovative strategies. The enzymatic synthesis, base-pairing properties, structure, and stability of oligonucleotides containing nucleobase- or 4'-hydroxymethyl-transposed nucleotides are discussed. The use of oligonucleotides containing nucleobase- or 4'-hydroxymethyl-transposed nucleotides as small oligonucleotide (e.g., human immunodeficiency virus integrase) inhibitors, in applications such as antisense therapy, silencing RNA (siRNA), or aptamer selections, is detailed.

Electron impact mass spectrometry of some ketosugar derivatives

The electron impact fragmentation of 1,2-O-isopropylidene-alpha-D-glycero-tetros-3-ulofuranose has been studied with the help of deuterium and 18O labelling. The effect of substituting a hydrogen atom of C-4 for a CH3 radical and that of replacing the carbonyl function with a cyanomethylenic substituent is also reported.