Ureas: Applications in Drug Design.

The unique hydrogen binding capabilities of ureas make them an important functional group to make drug-target interactions and thus incorporated in small molecules displaying broad range of bioactivities. The related research and numerous excellent achievements of ureas applicability in drug design for the modulation of selectivity, stability, toxicity and pharmacokinetic profile of lead molecules have become active topic. This review aims to provide insights in to the significance of urea in drug design by summarizing successful studies of various urea derivatives as modulators biological targets (viz. kinases, NAMPT, soluble epoxide hydrolases, mTOR, proteases, gyrB/parE, and epigenetic enzymes (such as HDAC, PRMT or DOT1L etc.). The findings of this review confirm the importance of urea moiety in medicinal chemistry and stimulate its use as a structural motif with rational decision making approach.

Bromomethylthioindole Inspired Carbazole Hybrids as Promising Class of Anti-MRSA Agents.

Series of N-substituted carbazole analogues bearing an indole ring were synthesized as anti-methicillin-resistant Staphylococcus aureus (MRSA) agents from a molecular hybridization approach. The representative compound 19 showed an MIC = 1 µg/mL against a panel of MRSA clinical isolates as it possessed comparable in vitro activities to that of vancomycin. Moreover, compound 19 also exhibited MIC = 1 µg/mL activities against a recent identified Z172 MRSA strain (vancomycin-intermediate and daptomycin-nonsusceptible phenotype) and the vancomycin-resistant Enterococcus faecalis (VRE) strain. In a mouse model with lethal infection of MRSA (4N216), a 75% survival rate was observed after a single dose of compound 19 was intravenously administered at 20 mg/kg. In light of their equipotent activities against different MRSA isolates and VRE strain, the data underscore the importance of designed hybrid series for the development of new N-substituted carbazoles as potential anti-MRSA agents.

Stem cell mobilizers targeting chemokine receptor CXCR4: renoprotective application in acute kidney injury.

We have discovered a novel series of quinazoline-based CXCR4 antagonists. Of these, compound 19 mobilized CXCR4(+) cell types, including hematopoietic stem cells and endothelial progenitor cells, more efficiently than the marketed 1 (AMD3100) with subcutaneous administration at the same dose (6 mg/kg) in mice. This series of compounds thus provides a set of valuable tools to study diseases mediated by the CXCR4/SDF-1 axis, including myocardial infarction, ischemic stroke, and cancer metastasis. More importantly, treatment with compound 19 significantly lowered levels of blood urea nitrogen and serum creatinine in rats with renal ischemia-reperfusion injury, providing evidence for its therapeutic potential in preventing ischemic acute kidney injury. CXCR4 antagonists such as 19 might also be useful to increase circulating levels of adult stem cells, thereby exerting beneficial effects on damaged and/or inflamed tissues in diseases that currently are not treated by standard approaches.

Function-oriented development of CXCR4 antagonists as selective human immunodeficiency virus (HIV)-1 entry inhibitors.

Motivated by the pivotal role of CXCR4 as an HIV entry co-receptor, we herein report a de novo hit-to-lead effort on the identification of subnanomolar purine-based CXCR4 antagonists against HIV-1 infection. Compound 24, with an EC50 of 0.5 nM against HIV-1 entry into host cells and an IC50 of 16.4 nM for inhibition of radioligand stromal-derived factor-1α (SDF-1α) binding to CXCR4, was also found to be highly selective against closely related chemokine receptors. We rationalized that compound 24 complementarily interacted with the critical CXCR4 residues that are essential for binding to HIV-1 gp120 V3 loop and subsequent viral entry. Compound 24 showed a 130-fold increase in anti-HIV activity compared to that of the marketed CXCR4 antagonist, AMD3100 (Plerixafor), whereas both compounds exhibited similar potency in mobilization of CXCR4(+)/CD34(+) stem cells at a high dose. Our study offers insight into the design of anti-HIV therapeutics devoid of major interference with SDF-1α function.

Discovery of 1-(2,4-dichlorophenyl)-N-(piperidin-1-yl)-4-((pyrrolidine-1-sulfonamido)methyl)-5-(5-((4-(trifluoromethyl)phenyl)ethynyl)thiophene-2-yl)-1H-pyrazole-3-carboxamide as a novel peripherally restricted cannabinoid-1 receptor antagonist with significant weight-loss efficacy in diet-induced obese mice.

After extensive synthetic efforts, we found that many structurally diverse bioisosteres could be generated via derivatizing the C-4 alkyl chain on the pyrazole ring of compound 3 (B/P = 1/33) with different electronegative groups. Especially when a sulfonamide or sulfamide moiety was added, resulting compounds exhibited not only potent CB1R activity but also a desired tPSA value over 90 Å(2), a threshold considered to possess a low probability to cross BBB, leading to the identification of compound 4 (B/P = 1/64) as a peripherally restricted CB1R antagonist. Apart from its significant weight-loss efficacy in DIO mice, compound 4 also displays 163 clean off-target profiles and is currently under development for treating obesity and the related metabolic syndrome.

Organocatalytic enantioselective domino Michael-aldol condensation of 5-oxoalkanal and alpha,beta-unsaturated aldehydes. Efficient assembly of densely functionalized cyclohexenes.

Organocatalytic Michael reaction of glutaraldehyde and 3-arylpropenal followed by the subsequent intramolecular aldol condensation provided 2-arylcyclohex-3-ene-1,3-dicarbaldehydes. Reactions with the 5-oxohexanal variant afforded the highly functionalized cyclohexenedicarbaldehydes in high diastereoselectivity and high enantioselectivity (>99% ee). Structure of the adduct 3j was confirmed unambiguously by X-ray analysis.