Nazarov-like cyclization reactions.

The Nazarov cyclization, a well-known method for the formation of cyclopentenones, mechanistically involves the 4π electrocyclization of a 1,4-pentadienyl cation, generated from cross-conjugated divinyl ketones. Recently, advances related to this cyclization, such as the incorporation of heteroatoms as well as the use of cyclopropanes as double bond equivalents have extended the scope of the original reaction. The modifications discussed in this review, which covers the years 2009-2013, have allowed the realization of both heteroatom- and homo-Nazarov cyclizations.

Small molecule inhibitors of HIV RT Ribonuclease H.

Two classes of compounds, thiocarbamates 1 and triazoles 2, have been identified as HIV RT RNase H inhibitors using a novel FRET-based HTS assay. The potent analogs in each series exhibited selectivity and were active in cell-based assays. In addition, saturable, 1:1 stoichiometric binding to target was established and time of addition studies were consistent with inhibition of RT-mediated HIV replication.

Novel pyrazolopyrimidines as highly potent B-Raf inhibitors.

A novel series of pyrazolo[1,5-a]pyrimidines bearing a 3-hydroxyphenyl group at C(3) and substituted tropanes at C(7) have been identified as potent B-Raf inhibitors. Exploration of alternative functional groups as a replacement for the C(3) phenol demonstrated indazole to be an effective isostere. Several compounds possessing substituted indazole residues, such as 4e, 4p, and 4r, potently inhibited cell proliferation at submicromolar concentrations in the A375 and WM266 cell lines, and the latter two compounds also exhibited good therapeutic indices in cells.

Identification of anthranilic acid derivatives as a novel class of allosteric inhibitors of hepatitis C NS5B polymerase.

A series of potent anthranilic acid-based inhibitors of the hepatitis C NS5B polymerase has been identified. The inhibitors bind to a site on NS5B between the thumb and palm regions adjacent to the active site as determined by X-ray crystallography of the enzyme-inhibitor complex. Guided by both molecular modeling and traditional SAR, the enzyme activity of the initial hit was improved by approximately 100-fold, yielding a series of potent and selective NS5B inhibitors with IC50 values as low as 10 nM.

Potent, selective, and orally bioavailable matrix metalloproteinase-13 inhibitors for the treatment of osteoarthritis.

Modification of alpha-biphenylsulfonamidocarboxylic acids led to potent and selective MMP-13 inhibitors. Compound 16 showed 100% oral bioavailability in rats and demonstrated >50% inhibition of bovine cartilage degradation at 10 ng/mL.

Thiourea inhibitors of herpesviruses. Part 3: Inhibitors of varicella zoster virus.

The preparation of alpha-methylbenzyl thioureas and their biological activity against varicella zoster virus is described. Several analogs demonstrated IC50s<0.1 microM and their SAR are discussed.

Thiourea inhibitors of herpes viruses. Part 2: N-Benzyl-N'-arylthiourea inhibitors of CMV.

A series of highly potent thiourea inhibitors of cytomegalovirus (CMV) with improved stability properties was prepared and evaluated. Compound 29 inhibited the virus in cultured HFF cells with IC50 of 0.2 nM.

Thiourea inhibitors of herpes viruses. Part 1: bis-(aryl)thiourea inhibitors of CMV.

Bis-(aryl)thioureas were found to be potent and selective inhibitors of cytomegalovirus (CMV) in cultured HFF cells. Of these, the thiazole analogue 38 was investigated as a potential development candidate.

Design strategies for the identification of MMP-13 and Tace inhibitors.

Inhibitors of matrix metalloprotease (MMP)-13 and tumor necrosis factor-alpha converting enzyme (TACE) have been highly sought as potential therapeutic agents for the treatment of osteoarthritis and rheumatoid arthritis, respectively. This review focuses on the published literature on these inhibitors from 2001 to mid-2003. Significant advances have been reported in the design and synthesis of potent and selective inhibitors of MMP-13 using hydroxamic acid and non-hydroxamate zinc chelators on a variety of scaffolds.

Pyrimido[1,2-b]-1,2,4,5-tetrazin-6-ones as HCMV protease inhibitors: a new class of heterocycles with flavin-like redox properties.

The synthesis and biological activity of pyrimidotetrazin-6-ones against HCMV protease is described. The mechanism of action for these inhibitors is the oxidation of several cysteine residues to generate cross-linked enzyme.

Identification of small molecule compounds that selectively inhibit varicella-zoster virus replication.

A series of nonnucleoside, N-alpha-methylbenzyl-N'-arylthiourea analogs were identified which demonstrated selective activity against varicella-zoster virus (VZV) but were inactive against other human herpesviruses, including herpes simplex virus. Representative compounds had potent activity against VZV early-passage clinical isolates and an acyclovir-resistant isolate. Resistant viruses generated against one inhibitor were also resistant to other compounds in the series, suggesting that this group of related small molecules was acting on the same virus-specific target.