Synthesis of a naphthyridone p38 MAP kinase inhibitor

Compound 1 is a p38 MAP kinase inhibitor potentially useful for the treatment of rheumatoid arthritis and psoriasis. A novel six-step synthesis suitable for large-scale preparation was developed in support of a drug development program at Merck Research Laboratories. The key steps include a tandem Heck-lactamization, N-oxidation, and a highly chemoselective Grignard addition of 4-(N-tert-butylpiperidinyl)magnesium chloride to a naphthyridone N-oxide. The N-oxide exerted complete chemoselectivity via chelation in directing the Grignard addition to the alpha position as opposed to 1,4-addition on the ene-lactam. The dihydropyridyl adduct was in situ aromatized with isobutylchloroformate followed by heating in pyridine. Syntheses of Grignard precursor, N-tert-butyl-4-chloro-piperidine, were accomplished via transamination with a quaternary ammonium piperidone or via addition of methylmagnesium chloride to an iminium ion. Utilizing this chemistry, multi-kilogram preparation of compound 1 was successfully demonstrated.     

Design and synthesis of coumarin substituted oxathiadiazolone derivatives having anti-inflammatory activity possibly through p38 MAP kinase inhibition

Compounds containing oxathiadiazolone nucleus bearing substituted coumarin ring were designed and synthesized while retaining the pharmacophores required for binding with p38 MAP kinase. A four-step synthetic scheme was employed for the synthesis of 7-methoxy-4-(3t?-substituted-2t?-oxo-1t?,2t?,3t?,5t?-oxathiadiazol-4t?-yl)-coumarin. The reactions were monitored by TLC and structures of the intermediates and the target compounds were ascertained by IR, NMR, Mass spectral data. The compounds were found to possess anti-inflammatory activity comparable to indomethacin. Superimposition studies of the target compounds with the lead p38 kinase inhibitors suggested that anti-inflammatory activity of the target compounds may be due to p38 MAP kinase inhibition. It was also suggested that methoxy group on coumarin nucleus may improve the binding profile with p38 MAP kinase.     

Synthesis of p38 MAP kinase inhibitor BIRB 796 and analogs via copper-mediated N-arylation reaction

Direct N-arylation of urea (5) with various arylboronic acids mediated by cupric acetate furnished BIRB796 and a range of N-substituted BIRB796 analogs in good to moderate yields in one step. Urea (5) was readily synthesized from commercially available compounds.     

Strategies to design pyrazolyl urea derivatives for p38 kinase inhibition: a molecular modeling study

The p38 protein kinase is a serine–threonine mitogen activated protein kinase, which plays an important role in inflammation and arthritis. A combined study of 3D-QSAR and molecular docking has been undertaken to explore the structural insights of pyrazolyl urea p38 kinase inhibitors. The 3D-QSAR studies involved comparative molecular field analysis (CoMFA) and comparative molecular similarity indices (CoMSIA). The best CoMFA model was derived from the atom fit alignment with a cross-validated r ² (q ²) value of 0.516 and conventional r ² of 0.950, while the best CoMSIA model yielded a q ² of 0.455 and r ² of 0.979 (39 molecules in training set, 9 molecules in test set). The CoMFA and CoMSIA contour maps generated from these models provided inklings about the influence of interactive molecular fields in the space on the activity. GOLD, Sybyl (FlexX) and AutoDock docking protocols were exercised to explore the protein–inhibitor interactions. The integration of 3D-QSAR and molecular docking has proffered essential structural features of pyrazolyl urea inhibitors and also strategies to design new potent analogues with enhanced activity.     

Synthesis and biological activities of 4-phenyl-5-pyridyl-1,3-thiazole derivatives as p38 MAP kinase inhibitors

A novel series of 4-phenyl-5-pyridyl-1,3-thiazole analogues possessing potent in vitro inhibitory activity against p38 mitogen-activated protein kinase and the release of tumor necrosis factor-alpha (TNF-alpha) from human monocytic THP-1 cells stimulated by lipopolysaccharide has been identified. Subsequent structure-activity relationship (SAR) studies and optimization for absorption, distribution, metabolism, and elimination (ADME) profiles led to the identification of compounds 7 g and 10b as orally active lead candidates that block the in vivo production of proinflammatory cytokine (TNF-alpha). In pharmacokinetic studies, compound 10b showed good oral administration in mice and demonstrated significant in vivo anti-inflammatory activity in an anti-collagen monoclonal antibody-induced arthritis mouse model (minimum effective dose (MED)=30 mg/kg). Further elucidation of this class of compounds may provide novel anti-inflammatory agents, such as anti-rheumatoid arthritis drugs.     

Activation of the stress-activated JNK and p38 MAP kinases in human cells by Photofrin-mediated photodynamic therapy

We have examined the possible role of the stress-activated JNK and p38 protein kinases in cellular sensitivity following Photofrin-mediated photodynamic therapy (PDT). Previously we reported that immortalized Li-Fraumeni syndrome (LFS) cells are more resistant to Photofrin-mediated PDT compared to normal human fibroblasts (NHF) at equivalent cellular Photofrin levels. In the current work we report that Photofrin-mediated PDT increased the activity of JNK1 and p38 within 30 min in both cell types. However, the increased activity of JNK1 and p38 was transient in the sensitive NHF cells and returned back to near basal levels by 3 h after PDT. In contrast, the resistant LFS cells exhibited a more prolonged activation of JNK and p38, which lasted for at least 11 h and 7 h after PDT, respectively. Blocking of the p38 pathway in LFS cells by transient infection with a recombinant adenovirus expressing a dominant negative mutant of p38 or in HeLa cells by stable transfection with a dominant negative mutant of p38 had no effect on cell survival following PDT. These data suggest that although Photofrin-mediated PDT is able to induce JNK1 and p38 in human cells, the p38 pathway alone does not play a major role in the sensitivity of LFS cells to Photofrin-mediated PDT.     

Evaluation of chiral purity for a substituted imidazole p38 MAP kinase inhibitor and its intermediates using a single chiral capillary electrophoresis method

The chiral separation of a substituted imidazole p38 MAP kinase inhibitor and its intermediates was investigated using capillary electrophoresis (CE) with various sulfated cyclodextrins. After initial screens, a single CE chiral method with a randomly sulfated beta-CD was selected for the evaluation of chiral purity for all three compounds. Operational parameters, such as the concentration of the chiral selectors, background electrolyte (or mobile phase) pH, organic modifiers, and temperature were varied in order to achieve an optimized method. The optimal method was validated in terms of linearity, sensitivity, precision, ruggedness, and specificity.     

Sequence, structure, and active site analyses of p38 MAP kinase: exploiting DFG-out conformation as a strategy to design new type II leads

A new knowledge, structure, and sequence based strategy involving the effective exploitation of the DFG-out conformation is delineated. A comprehensive analysis of the structure, sequence, cocrystals, and active sites of p38 MAP kinase crystal structures present in Protein Data Bank (PDB) and the FDA approved MAP kinase drugs has been done, and the information is used for the design of type II leads. The 98 crystal structures, 138 cocrystals, and 31 FDA drugs comprise of 7 different sequences of 2 organisms viz., Homo sapiens and Mus musculus differing in sequence length, constituting both homo- and heterochains. Multiple sequence alignment with ClustalW showed >95% sequence similarity with highly conserved domains and a high propensity for mutations in the activation loop. The bound ligands were extracted, and their interactions with DFG in and out conformations were studied. These cocrystals and FDA drugs were fragmented on the basis of their binding interactions and their affinity to ATP and allosteric sites. The fragment library thus generated contains 106 fragments with overlapping drug fragments. A blue print constituting three main parts viz., head (ATP region), linker (DFG region), and tail (allosteric region) has thus been formulated and used to design 64 type II p38 MAP kinase inhibitors. The above strategy has been employed to design potent type II p38 MAP kinase inhibitors, which are shown to be very promising.     

The p38 mitogen-activated protein kinase is involved in stress-induced phospholipase D activation in vascular smooth muscle cells

Oxidative stress has been implicated in mediation of vascular disorders. Earlier study showed that the exposure of vascular smooth muscle cells (VSMC) to pervanadate (hydrogen peroxide plus orthovanadate) resulted in the accumulation of [3H]phosphatidylbutanol. In this study, the effect of pervanadate on the activation of p38 mitogen-activated protein kinase (p38 MAPK) was studied in the VSMC. Pervanadate treatment activated p38 MAPK in a dose-and time-dependent manner. Interestingly, specific inhibition of p38 MAPK with SB203580 attenuated pervanadate-induced PLD activation. This correlates with the finding that expression of dominant negative mutants of MKK3/6 inhibited the PLD activation. SB203580 pretreatment also inhibited other cellular stressors (i.e. high osmolarity and UV light)-induced PLD activation. The possible correlationship of p38 MAPK activation with PKC was examined since PKC is reported to be involved in the pervanadate-induced PLD activation. Calphostin C, a PKC inhibitor, suppressed pervanadate-induced p38 MAPK and PLD activation in a dose-dependent manner. These results suggest that PKC-p38 MAPK may represent an upstream pathway of PLD in the signal transduction of cellular stress.     

Towards the improvement of the synthesis of novel 4(5)-aryl-5(4)-heteroaryl-2-thio-substituted imidazoles and their p38 MAP kinase inhibitory activity

A series of 2-alkylsulfanyl-4-(4-fluorophenyl)-5-(2-aminopyridin-4-yl)-substituted imidazoles was prepared and interaction possibilities of the 2-thioether moiety with phosphate/ribose binding pockets of p38 MAP kinase were investigated. Introduction of the alkyl/benzyl amino function at the pyridine moiety was carried out via nucleophilic substitution or via palladium catalyzed aryl-C-N-bond formation.     

Enhanced Ferromagnetism in a Mn3C12N12H12 Sheet

Based on a recent experimental study on the Ni₃C₁₂S₁₂ sheet [J. Am. Chem. Soc. 2013 , 135, 2462] and a theoretical study on the Mn₃C₁₂S₁₂ sheet [Nanoscale­ 2013 , 5, 10404], by using density functional theory combined with a thermodynamic model, it is shown that when sulfur atoms are replaced by ?NH? groups the resulting Mn₃C₁₂N₁₂H₁₂ sheet can exhibit strong ferromagnetism with a Curie temperature of 450 K. The enhanced ferromagnetism is due to two main factors: the reduced lattice constant and nitrogen is more effective in mediating magnetic couplings through p–d exchange interactions. Furthermore, it is also confirmed that the Mn₃C₁₂N₁₂H₁₂ sheet is kinetically and thermally stable, and displays half metallicity.     

Secretion of adenylate kinase 1 is required for extracellular ATP synthesis in C2C12 myotubes

Extracellular ATP (exATP) has been known to be a critical ligand regulating skeletal muscle differentiation and contractibility. ExATP synthesis was greatly increased with the high level of adenylate kinase 1 (AK1) and ATP synthase beta during C2C12 myogenesis. The exATP synthesis was abolished by the knock-down of AK1 but not by that of ATP synthase beta in C2C12 myotubes, suggesting that AK1 is required for exATP synthesis in myotubes. However, membrane-bound AK1beta was not involved in exATP synthesis because its expression level was decreased during myogenesis in spite of its localization in the lipid rafts that contain various kinds of receptors and mediate cell signal transduction, cell migration, and differentiation. Interestingly, cytoplasmic AK1 was secreted from C2C12 myotubes but not from C2C12 myoblasts. Taken together all these data, we can conclude that AK1 secretion is required for the exATP generation in myotubes.     

Effect of Cortisol on Calpains in the C2C12 and 3T3-L1 Cells

The present study was carried out to understand the effect of cortisol on calpain system in the C2C12 and 3T3-L1 adipocyte cells under co-culture system. Cells were co-cultured by using transwell inserts with a 0.4 μm porous membrane to separate C2C12 and 3T3-L1 preadipocyte cells. Each cell type was grown independently on the transwell plates. Following cell differentiation, inserts containing 3T3-L1 cells were transferred to C2C12 plates. Ten microgram per milliliter of cortisol was added to the medium. Following treatment for 3 days, the cells in the lower well were harvested for analysis. Calpains such as μ-calpain, m-calpain, and calpastatin were selected for the analysis. RT-PCR results indicated the significant increase in the mRNA expression of μ-calpain, m-calpain, and calpastatin. In addition, the confocal microscopical investigation indicated the cortisol treatment increases calpain expression in the C2C12 and 3T3-L1 cells. Taking all these together, cortisol treatment with co-culture system shows most reliable status of calpains expression in the cells, which is quite distinct from one-dimensional monocultured cells.     

Trifluoromethyl derivatives of insoluble small-HOMO-LUMO-gap hollow higher fullerenes. NMR and DFT structure elucidation of C2-(C74-D3h)(CF3)12, Cs-(C76-Td(2))(CF3)12, C2-(C78-D3h(5))(CF3)12, Cs-(C80-C2v(5))(CF3)12, and C2-(C82-C2(5))(CF3)12

Reaction of a mixture of insoluble higher fullerenes with CF3I at 500 degrees C produced a single abundant isomer of C74(CF3)12, C76(CF3)12, and C80(CF3)12, two abundant isomers of C78(CF3)12 and C82(CF3)12, and an indeterminant number of isomers of C84(CF3)12. Using a combination of 19F NMR spectroscopy, DFT calculations, and the structures and spectra of previously reported fullerene(CF3)n compounds, the most-probable structures of six of the seven isolated compounds were determined to be specific isomers of C2-(C74-D3h)(CF3)12, Cs-(C76-Td(2))(CF3)12), C2-(C78-D3h(5))(CF3)12), Cs-(C80-C2v(5))(CF3)12), C2-(C82-C2(5))(CF3)12), and C2-(C82-C2(3))(CF3)12) containing ribbons and/or loops of edge-sharing para-C6(CF3)2 hexagons. The seventh isolated compound is a C1 isomer of C78(CF3)12 containing two such ribbons. This set of compounds represents only the second reported isolable compound with the hollow C74-D3h cage and the first experimental evidence for the existence of the hollow fullerenes C76-Td(2), C78-D3h(5), C80-C2v(5), and C82-C2(5) in arc-discharge soots.     

C12-s-C12·2Br和C12En混合水溶液的胶团化行为

季铵盐二聚表面活性剂C12-s-C12@2Br(s=2、3、4、6)和非离子表面活性剂C12E10或C12E23在水溶液中生成混合胶团.其临界胶团总浓度cmcT值介于二元复配体系中各组分的临界胶团浓度和之间.当添加少量非离子型表面活性剂(在水溶液中的摩尔分数α2=0.1)时,混合胶团中C12E10或C12E23的摩尔分数均已超过0.35;随着溶液中非离子型表面活性剂含量的增大,混合胶团中逐渐以C12E10或C12E23成分为主.