Novel (R)-6,6a,7,8,9,10-hexahydro-5H-pyrazino[1,2-a][1,n]naphthyridines as potent and selective agonists of the 5-HT receptor.

A series of novel (R)-6,6a,7,8,9,10-hexahydro-5H-pyrazino[1,2-a][1,n]naphthyridines were identified as potent and selective agonists of the 5-HT receptor. Optimizations performed on a previously reported series of racemic tetrahydroquinoline-based tricyclic amines, delivered an advanced drug lead, (R)-4-(3,3,3-trifluoropropyl)-6,6a,7,8,9,10-hexahydro-5H-pyrazino[1,2-a][1,8]naphthyridine, which displayed excellent in vitro and in vivo pharmacological profiles.

Discovery of a lead series of potent benzodiazepine 5-HT receptor agonists with high selectivity in functional and binding assays.

A series of potential new 5-HT receptor scaffolds based on a simplification of the clinically studied, 5-HTR agonist vabicaserin, were designed. An in vivo feeding assay early in our screening process played an instrumental part in the lead identification process, leading us to focus on a 6,5,7-tricyclic scaffold. A subsequent early SAR investigation provided potent agonists of the 5-HT receptor that were highly selective in both functional and binding assays, had good rat PK properties and that significantly reduced acute food intake in the rat.

Tetrahydroquinoline-based tricyclic amines as potent and selective agonists of the 5-HT receptor.

The syntheses, structure-activity relationships (SARs), and biological activities of tetrahydroquinoline-based tricyclic amines as 5-HT receptor agonists are reported. An early lead containing a highly unique 6,6,7-ring system was optimized for both in vitro potency and selectivity at the related 5-HT receptor. Orally bioactive, potent, and selective 6,6,6-tricyclic 5-HT agonists were identified.

Design and synthesis of new tricyclic indoles as potent modulators of the S1P1 receptor.

Modulators of S1P1 have proven utility for the treatment of autoimmune disease and efforts to identify new agents with improved safety and pharmacokinetic parameters are ongoing. Several new S1P1 chemotypes were designed and optimized for potency and oral bioavailability. These new agents are characterized by a 'tricyclic fused indole array' and are highly potent agonists of the S1P1 receptor.

(7-Benzyloxy-2,3-dihydro-1H-pyrrolo[1,2-a]indol-1-yl)acetic Acids as S1P1 Functional Antagonists.

S1P1 is a validated target for treatment of autoimmune disease, and functional antagonists with superior safety and pharmacokinetic properties are being sought as second generation therapeutics. We describe the discovery and optimization of (7-benzyloxy-2,3-dihydro-1H-pyrrolo[1,2-a]indol-1-yl)acetic acids as potent, centrally available, direct acting S1P1 functional antagonists, with favorable pharmacokinetic and safety properties.

Complementary asymmetric routes to (R)-2-(7-hydroxy-2,3-dihydro-1H-pyrrolo[1,2-a]indol-1-yl)acetate.

Two distinct and scalable enantioselective approaches to the tricyclic indole (R)-2-(7-hydroxy-2,3-dihydro-1H-pyrrolo[1,2-a]indol-1-yl)acetate, an important synthon for a preclinical S1P(1) receptor agonist, are reported. Route 1 employs a modified version of Smith's modular 2-substituted indole synthesis as the key transformation. Route 2 involves a highly enantioselective CuH-catalyzed 1,4-hydrosilylation as the stereodefining step.

(1aR,5aR)1a,3,5,5a-Tetrahydro-1H-2,3-diaza-cyclopropa[a]pentalene-4-carboxylic acid (MK-1903): a potent GPR109a agonist that lowers free fatty acids in humans.

G-protein coupled receptor (GPCR) GPR109a is a molecular target for nicotinic acid and is expressed in adipocytes, spleen, and immune cells. Nicotinic acid has long been used for the treatment of dyslipidemia due to its capacity to positively affect serum lipids to a greater extent than other currently marketed drugs. We report a series of tricyclic pyrazole carboxylic acids that are potent and selective agonists of GPR109a.

Potent tricyclic pyrazole tetrazole agonists of the nicotinic acid receptor (GPR109a).

Tricyclic pyrazole tetrazoles which are potent partial agonists of the high affinity niacin receptor, GPR109a, have been discovered and optimized. One of these compounds has proven to be effective at lowering free fatty acids in vitro and in vivo.

Uncertainties in the oxygen isotopic composition of barium sulfate induced by coprecipitation of nitrate.

Coprecipitation of nitrate and sulfate by barium has probably resulted in significant error in numerous studies dealing with the oxygen isotopic composition of natural sulfates using chemical/thermal conversion of BaSO(4) and analysis by isotope ratio mass spectrometry. In solutions where NO(3) (-)/SO(4) (2-) molar ratios are above 2 the amount of nitrate coprecipitated with BaSO(4) reaches a maximum of approximately 7% and decreases roughly linearly as the molar ratio decreases. The fraction of coprecipitated nitrate appears to increase with decreasing pH and is also affected by the nature of the cations in the precipitating solution.