RESUMO
The amination of aryl halides has become one of the most commonly practiced C-N bond-forming reactions in pharmaceutical and laboratory syntheses. The widespread use of strong or poorly soluble inorganic bases for amine activation nevertheless complicates the compatibility of this important reaction class with sensitive substrates as well as applications in flow and automated synthesis, to name a few. We report a palladium-catalyzed C-N coupling using Et3N as a weak, soluble base, which allows a broad substrate scope that includes bromo- and chloro(hetero)arenes, primary anilines, secondary amines, and amide type nucleophiles together with tolerance for a range of base-sensitive functional groups. Mechanistic data have established a unique pathway for these reactions in which water serves multiple beneficial roles. In particular, ionization of a neutral catalytic intermediate via halide displacement by H2O generates, after proton loss, a coordinatively unsaturated Pd-OH species that can bind amine substrate triggering intramolecular N-H heterolysis. This water-assisted pathway operates efficiently with even weak terminal bases, such as Et3N. The use of a simple, commercially available ligand, PAd3, is key to this water-assisted mechanism by promoting coordinative unsaturation in catalytic intermediates responsible for the heterolytic activation of strong element-hydrogen bonds, which enables broad compatibility of carbon-heteroatom cross-coupling reactions with sensitive substrates and functionality.
Assuntos
Aminas/química , Água/química , Aminação , Carbono/química , Catálise , Ligantes , Nitrogênio/química , Paládio/químicaRESUMO
Synthesis and structure-activity relationships of cannabinoid-1 receptor (CB1R) inverse agonists based on dihydro-pyrano[2,3-b] pyridine and tetrahydro-1,8-naphtyridine scaffolds are presented. Rat food intake and pharmacokinetic evaluation of 13g, 13i, 13k and 17a revealed these compounds to be highly efficacious orally active modulators of CB1R.
Assuntos
Naftiridinas/química , Piridinas/química , Receptor CB1 de Canabinoide/agonistas , Redução de Peso/efeitos dos fármacos , Administração Oral , Animais , Ingestão de Alimentos , Humanos , Naftiridinas/síntese química , Naftiridinas/farmacologia , Farmacocinética , Piridinas/síntese química , Piridinas/farmacologia , Ratos , Receptor CB1 de Canabinoide/efeitos dos fármacos , Receptor CB2 de Canabinoide/agonistas , Receptor CB2 de Canabinoide/efeitos dos fármacos , Relação Estrutura-AtividadeRESUMO
This paper describes the discovery of N-[(4R)-6-(4-chlorophenyl)-7-(2,4-dichlorophenyl)-2,2-dimethyl-3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl]-5-methyl-1H-pyrazole-3-carboxamide (MK-5596, 12c) as a novel cannabinoid-1 receptor (CB1R) inverse agonist for the treatment of obesity. Structure-activity relationship (SAR) studies of lead compound 3, which had off-target hERG (human ether-a-go-go related gene) inhibition activity, led to the identification of several compounds that not only had attenuated hERG inhibition activity but also were subject to glucuronidation in vitro providing the potential for multiple metabolic clearance pathways. Among them, pyrazole 12c was found to be a highly selective CB1R inverse agonist that reduced body weight and food intake in a DIO (diet-induced obese) rat model through a CB1R-mediated mechanism. Although 12c was a substrate of P-glycoprotein (P-gp) transporter, its high in vivo efficacy in rodents, good pharmacokinetic properties in preclinical species, good safety margins, and its potential for a balanced metabolism profile in man allowed for the further evaluation of this compound in the clinic.
Assuntos
Fármacos Antiobesidade/síntese química , Piranos/síntese química , Piridinas/síntese química , Receptor CB1 de Canabinoide/antagonistas & inibidores , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Animais , Fármacos Antiobesidade/farmacocinética , Fármacos Antiobesidade/farmacologia , Ligação Competitiva , Peso Corporal/efeitos dos fármacos , Linhagem Celular , Cricetinae , Cricetulus , Cristalografia por Raios X , Cães , Agonismo Inverso de Drogas , Ingestão de Alimentos/efeitos dos fármacos , Canais de Potássio Éter-A-Go-Go/antagonistas & inibidores , Glucuronídeos/metabolismo , Haplorrinos , Hepatócitos/metabolismo , Humanos , Camundongos , Camundongos Knockout , Modelos Moleculares , Conformação Molecular , Piranos/farmacocinética , Piranos/farmacologia , Piridinas/farmacocinética , Piridinas/farmacologia , Ratos , Receptor CB1 de Canabinoide/genética , Estereoisomerismo , Relação Estrutura-AtividadeRESUMO
The synthesis, SAR and binding affinities of cannabinoid-1 receptor (CB1R) inverse agonists based on furo[2,3-b]pyridine scaffolds are described. Food intake, mechanism specific efficacy, pharmacokinetic, and metabolic evaluation of several of these compounds indicate that they are effective orally active modulators of CB1R.
Assuntos
Desenho de Fármacos , Furanos/síntese química , Piridinas/síntese química , Receptor CB1 de Canabinoide/agonistas , Animais , Benzopiranos , Cães , Furanos/química , Furanos/farmacologia , Haplorrinos , Humanos , Concentração Inibidora 50 , Camundongos , Camundongos Knockout , Estrutura Molecular , Piridinas/química , Piridinas/farmacologia , Ratos , Receptor CB1 de Canabinoide/genética , Relação Estrutura-AtividadeRESUMO
The synthesis, SAR and binding affinities are described for cannabinoid-1 receptor (CB1R) specific inverse agonists based on pyridopyrimidine and heterotricyclic scaffolds. Food intake and pharmacokinetic evaluation of several of these compounds indicate that they are effective orally active modulators of CB1R.
Assuntos
Agonistas de Receptores de Canabinoides , Obesidade/tratamento farmacológico , Pirimidinas/química , Administração Oral , Animais , Canabinoides/química , Química Farmacêutica/métodos , Desenho de Fármacos , Humanos , Concentração Inibidora 50 , Estrutura Terciária de Proteína , Ratos , Receptor CB1 de Canabinoide/agonistas , Receptor CB2 de Canabinoide/agonistas , Relação Estrutura-AtividadeRESUMO
Optimization of the biological activity for 5,6-diarylpyridines as CB1 receptor inverse agonists is described. Food intake and pharmacokinetic evaluation of 3f and 15c indicate that these compounds are effective orally active modulators of CB1.
Assuntos
Química Farmacêutica/métodos , Piridinas/química , Piridinas/síntese química , Receptor CB1 de Canabinoide/agonistas , Animais , Comportamento Animal/efeitos dos fármacos , Desenho de Fármacos , Comportamento Alimentar/efeitos dos fármacos , Concentração Inibidora 50 , Modelos Químicos , Conformação Molecular , Ratos , Ratos Sprague-Dawley , Relação Estrutura-Atividade , Temperatura , Tolueno/químicaRESUMO
Synthesis, SAR, and binding affinities are described for a new class of 1,8-naphthyridinone CB1 receptor specific inverse agonists. Food intake, knockout mouse, and pharmacokinetic evaluation of 14 indicate that this compound is an effective orally active modulator of CB1.