Synthesis, conformation, and antiviral activity of 5-methoxymethyl-2'-deoxycytidine analogs

Facile Modifications at the C4 Position of Pyrimidine Nucleosides via In Situ Amide Activation with 1H-Benzotriazol-1-yloxy-tris(dimethyl-amino)phosphonium Hexafluorophosphate

Two approaches for C4 modifications of silyl-protected thymidine, 2'-deoxyuridine, and 3'-azido-2',3'-dideoxythymidine (AZT) are described. In both, nucleoside amide activation with 1H-benzotriazol-1-yloxy-tris(dimethylamino)phosphonium hexafluorophosphate (BOP) and DBU yields O⁴ -(benzotriazol-1-yl) derivatives. These in situ-formed intermediates are reacted with various nucleophiles, resulting in C4 modifications. In the two-step, one-pot approach, the O⁴ -(benzotriazol-1-yl) nucleoside intermediates are initially produced by reactions of the nucleosides with BOP and DBU in THF. This step is fast and typically complete within 30 min. Subsequently, the O⁴ -(benzotriazol-1-yl) derivatives are reacted with nucleophiles, such as aliphatic and aromatic amines, thiols, and alcohols, under appropriate conditions. Workup, isolation, and purification lead to the desired C4-modified pyrimidine nucleosides in good to excellent yields. In the one-step approach, the nucleosides are reacted with BOP and DBU, in the presence of the nucleophile (only aliphatic and aromatic amines, and thiols have been tested). Where comparisons are possible, the one-step approach is generally superior. © 2019 by John Wiley & Sons, Inc.

Synthesis, molecular conformation and activity against herpes simplex virus of (E)-5-(2-bromovinyl)-2'-deoxycytidine analogs

Analogs of (E)-5-(2-bromovinyl)-2'-deoxycytidine (BrVdCyd) (1) by substitution at N(4) were synthesized to impart resistance against deamination. The anti-HSV-1 activity and solution conformation of these analogs were determined. N(4)-Acetyl-BrVdCyd (2) was a potent inhibitor of HSV-1 replication whereas N(4)-propanoyl-BrVdCyd (3) had good activity and N(4)-Butanoyl-BrVdCyd (4) had only low activity against HSV-1 replication. N(4)-Methyl-BrVdCyd (5) was devoid of activity against HSV-1.

Synthesis and antiviral activity of novel fluorinated 2',3'-dideoxynucleosides

A series of 5-(trifluoroethoxymethyl)-2',3'-dideoxyuridines and 5-[bis(trifluoroethoxy)-methyl]-2',3'-dideoxyuridines have been prepared and screened for antiviral activity. The conformations of these compounds are discussed on the bases of NOE studies and the MO calculations. Modelling and NOE studies suggest both syn- and anti conformations for these 5-(2,2,2-trifluoroethoxymethyl)- and 5-[bis(2,2,2-trifluoroethoxy)-methyl]- derivatives. The NOE parameters are also suggested to be more attributable to the nature of the fluorine atom than to structural or conformational changes. Compounds 17, 26 and 30 showed some activity in anti-HIV-1 and anti-HIV-2 assays, but the compounds were devoid of activity against HSV and human rhinovirus. The compounds tested exhibited low cytotoxicity and were inactive against a bank of cancer cells in vitro.