A series of 1-acyl-1H-[1,2,4]triazole-3,5-diamine analogues were synthesized as cyclin-dependent kinase (CDK) inhibitors. These compounds showed potent and selective CDK1 and CDK2 inhibitory activities and inhibited in vitro cellular proliferation in various human tumor cells. Representative compound 3b demonstrated in vivo efficacy in a human melanoma A375 xenograft model in nude mice.
The first direct arylation via C-OH bond activation of tautomerizable heterocycles has been achieved using phosphonium salts, on the basis of a combination of the phosphonium coupling and Suzuki-Miyaura cross-coupling conditions. Optimal reaction condition is obtained through screening of phosphonium salts, Pd catalysts, and bases. The direct arylation via C-OH bond activation tolerates a variety of tautomerizable heterocycles and aryl boronic acids. The mechanism of the Pd-catalyzed phosphonium coupling is proposed to proceed via a domino seven-step process including the unprecedented heterocycle-Pd(II)-phosphonium species. Application of the Pd-catalyzed direct arylation via C-OH bond activation using PyBroP leads to the most efficient synthesis of the biologically important 6-arylpurine ribonucleoside in a single step from unactivated and unprotected inosine.
High-throughput screening of a subset of the J&J compound library containing the carboxylic acid functional group uncovered a bromophenyl derivative as a moderate potent GPR40 agonist. Chemical elaboration of this bromophenyl led to the discovery of a novel series of GPR40 agonists with submicromolar potency. Among them, 22 and 24 behaved as full agonists when compared to the endogenous GPR40 ligand linolenic acid in a functional Ca+2 flux assay in HEK cells expressing GPR40 receptor. Several GPR40 agonists have also demonstrated the ability to induce glucose-mediated insulin secretion in the mouse MIN6 pancreatic beta-cell line. Our data supports the hypothesis that GPR40 may play an important role in fatty acid-mediated glucose-dependent insulin secretion. Compound 22 exhibited good pharmacokinetic profile in rat and may serve as a good candidate for in vivo study and may help to determine if GPR40 agonists would be beneficial in the treatment of type II diabetes.
An efficient two-step procedure is described to convert the Biginelli 3,4-dihydropyrimidin-2(1H)-one to various multifunctionalized pyrimidines via the Kappe dehydrogenation and a new mild PyBroP-mediated coupling with C, N, O, and S nucleophiles, which provides a readily accessible multifunctionalized pyrimidine template for diversity-oriented synthesis.
The solid phase synthesis of
3,4-disubstituted-7-carbamoyl-1,2,3,4-tetrahydroquinoxalin-2-ones
8
is described. 4-Fluoro-3-nitrobenzoic acid is tethered to a solid
support via the acid group. Aromatic
substitution of the resin-bound aryl fluoride with an α-amino ester
is carried out in the presence
of DIEA in DMF. The reduction of the aryl nitro group with
SnCl2·H2O and subsequent
intramolecular cyclization result in the formation of the core
quinoxalinone. Selective alkylation
at the N-4 position of the quinoxalinone is accomplished with alkyl
halides in the presence of K2CO3.
The desired products are cleaved from solid supports and obtained
in from 32 to 93% isolated yields.
On the basis of previous studies, we identified pyrazine-pyridine A as a potent vascular endothelial growth factor inhibitor and pyrimidine-pyridine B as a moderately potent cyclin dependent kinase (CDK) inhibitor. A proposed combination of CGP-60474 and compound B led to the discovery of [1,3,5]triazine-pyridine as a new series of potent CDK inhibitors. Palladium-catalyzed C-C bond formation reactions, particularly the Negishi coupling reaction, were used to assemble various triazine-heteroaryl analogues effectively. Among them, compound 20 displayed high inhibitory potency at CDK1 (IC(50) = 0.021 microM), CDK2, and CDK5 and submicromolar potency at CDK4, CDK6, and CDK7. Compound 20 also displayed high potency at GSK-3beta. It demonstrated potent antiproliferative activity on various tumor cell lines, including HeLa, HCT-116, U937, and A375. When 20 was administered intraperitoneally at 150 and 125 mg/kg to nude mice bearing human A375 xenografts, the compound produced a significant survival increase. Molecular docking studies were conducted in an attempt to enhance the understanding of the observed structure-activity relationship.
Attempts to design the macrocyclic maleimides as selective protein kinase C gamma inhibitors led to the unexpected discovery of a novel series of potent and highly selective glycogen synthase kinase-3beta (GSK-3beta) inhibitors. Palladium-catalyzed cross-coupling reactions were used to synthesize the key intermediates 17 and 22 that resulted in the synthesis of novel macrocycles. All three macrocyclic series (bisindolyl-, mixed 7-azaindoleindolyl-, and bis-7-azaindolylmaleimides) were found to have submicromolar inhibitory potency at GSK-3beta with various degrees of selectivity toward other protein kinases. To gain the inhibitory potency at GSK-3beta, the ring sizes of these macrocycles may play a major role. To achieve the selectivity at GSK-3beta, the additional nitrogen atoms in the indole rings may contribute to a significant degree. Overall, the bis-7-azaindolylmaleimides 28 and 29 exhibited little or no inhibitions to a panel of 50 protein kinases. Compound 29 almost behaved as a GSK-3beta specific inhibitor. Both 28 and 29 displayed good potency in GS cell-based assay. Molecular docking studies were conducted in an attempt to rationalize the GSK-3beta selectivity of azaindolylmaleimides.
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