Research on L-nucleosides. Synthesis and biological evaluation of a series of L- and D-2',3'-dideoxy-3'-[tris(methylthio)methyl]-beta-pentofuranosyl nucleosides

Simplified analogues of immucillin-G retain potent human purine nucleoside phosphorylase inhibitory activity

A set of deazaguanine derivatives 1-3 targeting human purine nucleoside phosphorylase (hPNP) have been designed and synthesized. The new compounds are characterized by the presence of a structurally simplified "azasugar" motif to be more easily accessible by chemical synthesis than previous inhibitors. In the enzymatic assays, some of the new derivatives proved to be able to inhibit hPNP at low nanomolar concentration, thereby showing the same inhibitory potency in vitro as immucillin-H (IMH). Molecular docking experiments revealed a binding mode to hPNP essentially identical to that of IMH. As a result, the lower in vivo activity exhibited by 1d, compared with that exhibited by IMH, might be ascribed to differences in the pharmacokinetic, rather than pharmacodynamic, profile between these compounds. Derivatives 1a, 1d, and 2c emerged as the most active compounds within this new set and may represent interesting leads in the search for novel hPNP inhibitors.

Cytostatic and antiviral 6-arylpurine ribonucleosides. Part 7: Synthesis and evaluation of 6-substituted purine l-ribonucleosides

A series of purine l-ribonucleosides 2a-2i bearing diverse C-substituents (alkyl, aryl, hetaryl or hydroxymethyl) in the position 6 were prepared by Pd-catalyzed cross-coupling reactions of 6-chloro-9-(2,3,5-tri-O-acetyl-beta-l-ribofuranosyl)purine with the corresponding organometallics followed by deprotection. Unlike their d-ribonucleoside enantiomers that possess strong cytostatic and anti-HCV activity, the l-ribonucleosides were inactive except for 6-benzylpurine nucleoside 2h showing moderate anti-HCV effect in replicon assay. A triphosphate of 2h did not inhibit HCV RNA polymerase.

On the role of polarizability in QSAR

The polarizability of a molecule, an important physical property, is currently attracting our attention particularly in the area of QSAR for chemical-biological interactions. In this report, the polarizability effects on ligand-substrate interactions has been discussed in terms of NVE (number of valence electrons) using additive values for valence electrons and the formulation of a total number of 51 QSAR. The QSAR model can be illustrated by Eq. I. log 1/C = a(NVE) +/- constant

Microwave-assisted synthesis and biological evaluation of novel uracil derivatives inhibiting human thymidine phosphorylase

New 5-chloro-6-substituted-uracil derivatives have been prepared by microwave assisted-synthesis and tested in vitro as thymidine phosphorylase inhibitors. One of these compounds showed potent inhibitory activity, with an IC50 value in the submicromolar range. The biological activity of the new compounds is discussed in terms of structure-activity relationship.