Design, Synthesis and Anti Flaviviridae Activity of N6-, 5',3'-O- and 5',2'-O-Substituted Adenine Nucleoside Analogs

Abstract

The Flaviviridae virus family presents linear, plus sense, single-stranded RNA genome of 9.6 to 12.3-kilobases in length and is responsible for about seventy diseases, of which thirteen in humans. The viruses belonging to this family, are divided in three different genera, showing a great similarity in virion morphology, genome organization and replication strategy:1) Hepacivirus [Hepatitis C Virus (HCV)], Flavivirus [e.g. Yellow Fever Virus (YFV), Dengue Fever Virus (DFV), West Nile Virus (WNV)], and Pestivirus [Bovine Viral Diarrhea Virus (BVDV), Border Disease Virus (BDV)]. [2][3][4][5] Bovine viral diarrhea virus (BVDV), the prototype representative of the Pestivirus genus, is ubiquitous and causes a range of clinical manifestations, including abortion, teratogenesis, respiratory problems, chronic wasting syndrome, immune system dysfunction, and predisposition to secondary viral and bacterial infections. 5)Regardless of the availability of vaccines 6) against BVDV and the increasingly elaborate eradication or control of programs, BVDV continues to be a financial burden to the farming industry. An alternative approach against BVDV infections could be the use of antiviral agents that specifically inhibit the replication of the virus. Although not suited to treat large herds, it could be important to have selective anti-Pestivirus compounds on hand.Recently, a number of selective anti-BVDV compounds have been reported. These include the following: polymerase inhibitors i.e. N-propyl-N-[2-(2H-1,2,4-triazino[5,6-b]indol-3-ylthio)ethyl]-1-propanamine (VP32947), 7) a thiazole urea derivative, 8) a cyclic urea derivative 9) and inhibitors of the NS3/NS4A protease, for example, a boron-modified peptidyl mimetic.10) Aromatic cationic molecules have also been reported to inhibit BVDV replication, although the mechanism of action remains to be elucidated.11) Other BVDV inhibitors target cellular enzymes such as the a-glucosidase 12-14) and inosine monophosphate dehydrogenase (IMPDH).15) Recently, a new highly selective BVDV polymerase inhibitor of pestivirus replication, 5-[(4-bromophenyl)methyl]-2-phenyl-5H-imidazo[4,5-c]pyridine (BPIP), was reported. 16)Like BVDV, HCV also belongs to the Flaviviridae family. It is an important cause of chronic hepatitis throughout the world and is the most common factor involved in the development of liver cirrhosis and hepatocellular carcinoma. 17,18) The licensed therapy based on the combination of pegylated interferon-a with the broad spectrum antiviral agent ribavirin, has a limited efficacy (about 60%) and there are important side effects associated with the therapy. Therefore, highly effective and selective inhibitors of HCV replication are urgently required. 19) BVDV is considered to be a valuable surrogate virus model for identifying and characterizing antiviral agents for use against HCV. 20) In some aspects of viral replication, BVDV is more advantageous than the currently used HCV replicon systems 21,22) because this latter does not present a complete replication cycle thus...

Synthesis of Disaccharide Nucleosides by the O‐Glycosylation of Natural Nucleosides with Thioglycoside Donors

“…To determine the reason for this, we collected 1 H NMR spectra of 38 a, [38] in which the 6-NH 2 group is not protected and the 3'-and 5'-OH groups are protected with TBDPS (to increase the solubility of the compound in an organic solvent), and 6-N-benzoyl-3',5'-O-bis-TBDPS-2'-deoxyadenosine 38 b [39] in the absence and presence of TolSCl and AgOTf (in CDCl 3 at À40 8C).…”

Antiviral activity of benzimidazole derivatives. II. Antiviral activity of 2-phenylbenzimidazole derivatives

“…39 Briefly, the expression plasmid encoding the N-terminal His-tagged C-terminal 24-amino-acid-deleted BVDV-NS5B was transformed into the Escherichia coli strain Rosetta™2 (DE3) pLysS (Novagene), and the transformants were then cultured in 5 mL of LB medium with 25 lg/mL kanamycin and 30 lg/mL chloramphenicol at 30°C overnight. Cultures were diluted into 1 L of LB medium with 25 lg/mL kanamycin and 30 lg/mL chloramphenicol and incubated at 30°C until the A 600 reached 0.6-0.7.…”

Synergistic experimental/computational studies on arylazoenamine derivatives that target the bovine viral diarrhea virus RNA-dependent RNA polymerase

“…To examine this inhibition in more detail, we cloned and expressed the BVDV NS5B, 28 and studied the effects of compounds 32 and 42 on the activity of this viral protein. The enzymatic inhibition assays showed that these compounds inhibit the RNA polymerase at micromolar concentrations, in a dose dependent way, ultimately indicating that the RdRp is indeed their target.…”

“…35,36 Despite the enormous size of the conformational space for a given ligand, current docking methodologies have been successfully employed by our group in reproducing crystallographic evidences as well as to predict putative binding modes. 22,28,31,32,37 However, conformational sampling also plays an important role in calculating the binding free energy accurately and efficiently. The conformational flexibility of a given inhibitor and its receptor can be taken into account, resorting to a wise strategy that employs a rapid and lower level method such as flexible inhibitor/rigid receptor docking at the beginning (Section 3), and turning to the more accurate and quantitative method as the MM/PBSA analysis 35 sampled by molecular dynamics (MD) simulations only once the best pose has been identified and all eventual available criteria have been satisfied.…”