Towards a TREK-1/2 (TWIK-Related K+ Channel 1 and 2) dual activator tool compound: Multi-dimensional optimization of BL-1249.

This letter describes a focused, multi-dimensional optimization campaign around BL-1249, a fenamate class non-steroidal anti-inflammatory and a known activator of the K2P potassium channels TREK-1 (K2P2.1) and TREK-2 (K2P10.1). While BL-1249 has been widely profiled in vitro as a dual TREK-1/2 activator, poor physicochemical and DMPK properties have precluded a deeper understanding of the therapeutic potential of these key K2P channels across a broad spectrum of peripheral and central human disease. Here, we report multi-dimensional SAR that led to a novel TREK-1/2 dual activator chemotype, exemplified by ONO-2960632/VU6011992, with improved DMPK properties, representing a new lead for further optimization towards robust in vivo tool compounds.

Discovery of Novel Central Nervous System Penetrant Metabotropic Glutamate Receptor Subtype 2 (mGlu2) Negative Allosteric Modulators (NAMs) Based on Functionalized Pyrazolo[1,5- a]pyrimidine-5-carboxamide and Thieno[3,2- b]pyridine-5-carboxamide Cores.

A scaffold hopping exercise from a monocyclic mGlu2 NAM with poor rodent PK led to two novel heterobicyclic series of mGlu2 NAMs based on either a functionalized pyrazolo[1,5- a]pyrimidine-5-carboxamide core or a thieno[3,2- b]pyridine-5-carboxamide core. These novel analogues possess enhanced rodent PK, while also maintaining good mGlu2 NAM potency, selectivity (versus mGlu3 and the remaining six mGlu receptors), and high CNS penetration. Interestingly, SAR was divergent between the new 5,6-heterobicyclic systems.

The discovery of VU0652957 (VU2957, Valiglurax): SAR and DMPK challenges en route to an mGlu4 PAM development candidate.

This letter describes the first account of the chemical optimization (SAR and DMPK profiling) of a new series of mGlu4 positive allosteric modulators (PAMs), leading to the identification of VU0652957 (VU2957, Valiglurax), a compound profiled as a preclinical development candidate. Here, we detail the challenges faced in allosteric modulator programs (e.g., steep SAR, as well as subtle structural changes affecting overall physiochemical/DMPK properties and CNS penetration).

Discovery and Characterization of 1H-Pyrazol-5-yl-2-phenylacetamides as Novel, Non-Urea-Containing GIRK1/2 Potassium Channel Activators.

The G protein-gated inwardly-rectifying potassium channels (GIRK, Kir3) are a family of inward-rectifying potassium channels, and there is significant evidence supporting the roles of GIRKs in a number of physiological processes and as potential targets for numerous indications. Previously reported urea containing molecules as GIRK1/2 preferring activators have had significant pharmacokinetic (PK) liabilities. Here we report a novel series of 1H-pyrazolo-5-yl-2-phenylacetamides in an effort to improve upon the PK properties. This series of compounds display nanomolar potency as GIRK1/2 activators with improved brain distribution (rodent Kp > 0.6).

Silanediol-Catalyzed Chromenone Functionalization.

Promising levels of enantiocontrol are observed in the silanediol-catalyzed addition of silyl ketene acetals to benzopyrylium triflates. This rare example of enantioselective, intermolecular chromenone functionalization with carbonyl-containing nucleophiles has potential applications in the synthesis of bioactive chromanones and tetrahydroxanthones.

Carbon-Silicon Bond Formation in the Synthesis of Benzylic Silanes.

Sterically encumbered organosilanes can be difficult to synthesize with conventional, strongly basic reagents; the harsh reaction conditions are often low yielding and not suitable for many functional groups. As an alternative to the typical anionic strategies to construct silanes, the coupling of benzylic halides and arylhalosilanes with sonication has been identified as a high yielding and general strategy to access bulky and functionalized benzylic silanes. This new methodology provides a solution for the synthesis of families of bulky benzylic silanes for study in catalysis and other areas of chemical synthesis.

Chiral silanediols in anion-binding catalysis.

A perfect pair: Silanediols are effective catalysts for the addition of silyl ketene acetals to N-acylisoquinolinium ions. Importantly, this is the first example of a silanediol plausibly participating in anion-binding catalysis, a relatively new direction in the field of hydrogen-bond-donor catalysis. The chiral, enantiopure C2 -symmetric silanediol 1 catalyzes enantioselective transformations.

Evidence of enhanced conjugation in ortho-arylene ethynylenes with transition metal coordination.

The effective conjugation of ortho and ortho-alt-para-arylene ethynylenes, with appropriately positioned pyridine and pyrazine heterocycles, increases upon binding to Ag(I) and Pd(II) cations. Significant bathochromic shifts in the electronic spectra, witnessed upon introduction of these metal bridges, are consistent with enhanced electron delocalization in the unsaturated backbone. Control studies suggest that this electronic behavior is attributable exclusively (in the case of Ag(I)) or partially (in the case of Pd(II)) to conformational restrictions of the conjugated backbones.

Silanediols: a new class of hydrogen bond donor catalysts.

Silanediols are introduced as a new class of hydrogen bond donor catalysts for the activation of nitroalkenes toward nucleophilic attack. Excellent yields of product are obtained for the conjugate addition of indole to ß-nitrostyrene catalyzed with a stable, storable dinaphthyl-derived silanediol. The preparation and structural characterization of a C(2)-symmetric chiral silanediol is also reported along with its ability to catalyze the conjugate addition reaction.