Laval Chan

A novel class of 1,3-oxathiolane nucleoside analogues having potent anti-HIV activity

Abstract We have developed a novel class of 1,3-oxathiolane nucleoside analogues which were evaluated for anti-HIV activity in the MT-4 cell line. BCH-371 , the adenine derivative, has been found to exhibit significant anti-HIV activity.

Antiviral properties of a series of 1,6-naphthyridine and 7, 8-dihydroisoquinoline derivatives exhibiting potent activity against human cytomegalovirus.

ABSTRACT A series of 1,6-naphthyridine (L. Chan, H. Jin, T. Stefanac, J. F. Lavallee, G. Falardeau, W. Wang, J. Bedard, S. May, and L. Yuen, J. Med. Chem. 42:3023–3025, 1999) and isoquinoline (L. Chan, H. Jin, T. Stefanac, W. Wang, J. F. Lavallee, J. Bedard, and S. May, Bioorg. Med. Chem. Lett. 9:2583–2586, 1999) analogues exhibiting a high level of anti-human cytomegalovirus (HCMV) activity were investigated in a series of studies aimed at better understanding the mechanism of action of some representatives of this class of compounds. In vitro antiviral profiling revealed that these compounds were active against a narrow spectrum of viruses, essentially the human herpesviruses and type 2 rhinovirus. In HCMV assays, a 39- to 223-fold lower 50% inhibitory concentration was obtained for compound A1 than for ganciclovir against strains AD 169 and Towne. In addition, ganciclovir, foscarnet, cidofovir, and BDCRB (2-bromo-5,6-dichloro-1-β-d-ribofuranosylbenzimidazole)-resistant HCMV strains remained susceptible to 1,6-naphthyridines and 7,8-dihydroisoquinolines tested in this study, supporting the view that a novel mechanism of action could be involved. Drug combination studies showed a small but significant synergistic antiviral effect between compound B2 and ganciclovir. Cytotoxicity profiling of representative compounds under various cell growth conditions indicated a generally similar cytotoxic effect, relative to ganciclovir, in log-phase growing cells. However, in stationary cells, a relatively higher level of toxicity was observed than that for control compound. Effect of time of drug addition showed that the anti-HCMV activity of compound A1, ganciclovir, and cidofovir was lost at approximately the same time (72 h postinfection), indicating that the compound was affecting events at the early and late stage of virus replication. This interpretation is also supported by reduction of de novo synthesis of pp65 tegument protein and lack of any effect of the compound on viral adsorption. A reduction of the HCMV enhancer-promoter-directed luciferase expression was also observed in a stably transfected cell line when compound A1 was present at relatively high concentrations.

Isoquinoline-6-carboxamides as potent and selective anti-human cytomegalovirus (HCMV) inhibitors.

Structure-activity relationship studies on our newly identified anti-HCMV compounds, the 1,6-naphthyridines led to the identification of isoquinoline-6-carboxamides as potent and selective anti-HCMV agents.

Identification of novel nucleotide phosphonate analogs with potent anti-HCMV activity.

We have recently described the discovery of new leads in the area of anti-HCMV research. Further structure-activity relationship studies have allowed us to identify potent and selective anti-HCMV nucleotide analogs. The synthesis as well as structure-activity relationship studies are described.

Substituted 1,6-naphthyridines as human cytomegalovirus inhibitors: conformational requirements.

Substituted 1,6-naphthyridine derivatives, a new class of human cytomegalovirus inhibitors, were prepared to demonstrate the role of intramolecular hydrogen bonds to maintain the compounds in their active conformation.

Discovery of Thienoimidazole-Based HCV NS5A Genotype 1a and 1b Inhibitors.

The discovery of potent thienoimidazole-based HCV NS5A inhibitors is herein reported. A novel method to access the thienoimidazole [5,5]-bicyclic system is disclosed. This method gave access to a common key intermediate (6) that was engaged in Suzuki or Sonogashira reactions with coupling partners bearing different linkers. A detailed study of the structure-activity relationship (SAR) of the linkers revealed that aromatic linkers with linear topologies are required to achieve high potency for both 1a and 1b HCV genotypes. Compound 20, with a para-phenyl linker, was identified as a potential lead displaying potencies of 17 and 8 pM against genotype 1a and 1b replicons, respectively.

Synthesis and antiviral activities of N-9-oxypurine 1,3-dioxolane and 1,3-oxathiolane nucleosides

Two series of 1,3-dioxolanes and 1,3-oxathiolane nucleosides containing N-9-oxypurine were synthesized as potential antiviral agents. These compounds were prepared by reacting the sugar moieties with iodo- or bromotrimethylsilane, followed by treatment with a mixture of sodium hydride and the desired N-hydroxy purine base. The preparation of these N-hydroxybases was also described. No significant antiviral activity was observed against HIV, HBV, HSV-1, HSV-2, or HCMV.

Design and synthesis of new potent human cytomegalovirus (HCMV) inhibitors based on internally hydrogen-bonded 1,6-naphthyridines.

1,6-Naphthyridine-2-carboxylic acid benzylamides are potent anti-HCMV compounds. Replacement of the amide moiety by other groups containing internal hydrogen bonds was undertaken to extend the SAR. Our results indicated that the urca derivatives showed very good activity.

Design and evaluation of dihydroisoquinolines as potent and orally bioavailable human cytomegalovirus inhibitors.

Following the identification of first pass metabolism issues with our recently described anti-HCMV compounds, the naphthyridines and isoquinolines, we have designed a class of novel metabolically stable and orally bioavailable anti-HCMV agents, the dihydroisoquinolines.

Design and synthesis of A novel class of nucleotide analogs with anti-HCMV activity

A novel class of cyclic nucleotide analogs has shown anti-HCMV activity. The synthesis as well as structure-activity relationship studies are presented.