Potent cholesteryl ester transfer protein inhibitors of reduced lipophilicity: 1,1'-spiro-substituted hexahydrofuroquinoline derivatives.

A series of 1,1'-spiro-substituted hexahydrofuroquinoline derivatives exhibiting potent cholesteryl ester transfer protein (CETP) inhibition at reduced lipophilicity was identified. A focused structure-activity relationship (SAR) exploration led to the potent and comparatively polar CETP inhibitor 26 showing robust high density lipoprotein-cholesterol (HDL-C) elevation and low density lipoprotein-cholesterol (LDL-C) reduction in transgenic hCETP/hApoB-100 mice. Compound 26 was also shown to positively differentiate from highly lipophilic CETP inhibitors in its complete elimination from fat tissue in hCETP transgenic mice as evident within 21 days after cessation of treatment. In addition, compound 26 showed no significant effects on aldosterone secretion from H295R cells, as well as no significant effects on blood pressure and electrocardiogram parameters in telemetrized cynomolgus monkeys.

Thieno[3,2-c]pyrazoles: a novel class of Aurora inhibitors with favorable antitumor activity.

A novel series of 3-amino-1H-thieno[3,2-c]pyrazole derivatives demonstrating high potency in inhibiting Aurora kinases was developed. Here we describe the synthesis and a preliminary structure-activity relationship, which led to the discovery of a representative compound (38), which showed low nanomolar inhibitory activity in the anti-proliferation assay and was able to block the cell cycle in HCT-116 cell line. This compound demonstrated favorable pharmacokinetic properties and good efficacy in the HL-60 xenograft tumor model.

1,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles: identification of a potent Aurora kinase inhibitor with a favorable antitumor kinase inhibition profile.

The optimization of a series of 5-phenylacetyl 1,4,5,6-tetrahydropyrrolo[3,4-c]pyrazole derivatives toward the inhibition of Aurora kinases led to the identification of compound 9d. This is a potent inhibitor of Aurora kinases that also shows low nanomolar potency against additional anticancer kinase targets. Based on its high antiproliferative activity on different cancer cell lines, favorable chemico-physical and pharmacokinetic properties, and high efficacy in in vivo tumor models, compound 9d was ultimately selected for further development.

Potent and selective Aurora inhibitors identified by the expansion of a novel scaffold for protein kinase inhibition.

Potent and selective Aurora kinase inhibitors were identified from the combinatorial expansion of the 1,4,5,6-tetrahydropyrrolo[3,4-c]pyrazole bi-cycle, a novel and versatile scaffold designed to target the ATP pocket of protein kinases. The most potent compound reported in this study had an IC(50) of 0.027 microM in the enzymatic assay for Aur-A inhibition and IC(50)s between 0.05 microM and 0.5 microM for the inhibition of proliferation of different tumor cell lines.

Polymer-assisted solution-phase (PASP) Suzuki couplings employing an anthracene-tagged palladium catalyst.

A general method for polymer-assisted solution-phase (PASP) Suzuki reactions employing a combination of anthracene-tagged palladium catalyst and anthracene-tagged boronic acid with a polymer-supported carbonate base is reported. The anthracene-tagged catalyst allows for the easy removal of the Pd catalyst along with the dissociated phosphine ligand and phosphine oxide byproducts by sequestration through a chemoselective Diels-Alder reaction with a maleimide resin. The polymer-supported carbonate base facilitates the removal of excess boronic acid and the borane-containing byproducts present at the end of the coupling reaction. The Suzuki coupling reaction can be efficiently conducted by using combinations of the anthracene-tagged Pd catalyst, polymer-supported carbonate base, and anthracene-tagged boronic acid to yield the desired product in high purity and yield without the use of chromatography.

Stereoselectivity of NCS-382 binding to gamma-hydroxybutyrate receptor in the rat brain.

gamma-Hydroxybutyric acid (GHB), a naturally occurring metabolite of gamma-aminobutyric acid (GABA), has been postulated to act both as a specific agonist of GHB receptors and as a weak GABA(B) receptor agonist. The racemic compound 6,7,8,9-tetrahydro-5-hydroxy-5H-benzocyclohept-6-ylideneacetic acid (RS-NCS-382), the only available antagonist of GHB receptors, has been resolved in two enantiomers, R- and S-; the potency of the latter to displace 4-hydroxy [2-3-(3)H] butyric acid ([(3)H]GHB) and [(3)H]NCS-382 from GHB receptors, on one hand, and [(3)H]baclofen from GABA(B) receptors on the other was compared in rat brain homogenates. R-NCS-382 was found to be twice and 60 times more potent than the RS- and S-forms, respectively, in displacing [(3)H]GHB and 2 and 14 times, respectively, in displacing [(3)H]NCS-382 from GHB binding. Neither RS-NCS-382 nor its enantiomers inhibited [(3)H]baclofen binding up to a concentration of 1 mM. Our results demonstrate that R-NCS-382 is the enantiomer of RS-NCS-382 with higher affinity for GHB receptors.