- 3-Deoxy-3-fluoropyridoxamine 5'-phosphate: Synthesis and chemical and biological properties of a coenzyme B6 analog
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The C-3 deoxygenation of CDP-6-deoxy-L-threo-D-glycero-4-hexulose is the key step in the biosynthesis of ascarylose which is a 3,6-dideoxy sugar found in the lipopolysaccharide of Yersinia pseudotuberculosis. This transformation, achieved by the catalysis of CDP-6-deoxy-L-threo-D-glycero-4-hexulose-3-dehydrase (E1) and CDP-6-deoxy-L-threo-D-glycero-4-hexulose-3-dehydrase reductase (E3), is initiated by a reversible dehydration followed by a stepwise electron transfer from NADH to reduce the resulting glucoseen-PMP adduct. An organic radical intermediate has been detected by EPR during E1-E3 catalysis, and its characteristics are consistent with a phenoxyl radical. Its formation has been hypothesized to involve a tautomerization of the glucoseen-PMP intermediate to a PMP-quinone methide species, which then serves as the electron acceptor during the reduction. In order to gain further experimental evidence supporting this proposed mechanism, the title compound (F-PMP) was synthesized and tested for its competence as a cofactor for the E1-E3 reaction. Upon incubation with F-PMP, no C-3 deoxysugar product could be detected in the mixture. This result initially appeared to support the prediction that the 3-F substituent would prevent the tautomerization and thus inhibit the subsequent reduction. However, further analysis showed that the catalysis was actually arrested at the dehydration step since no 18O was incorporated at C-3 of the recovered substrate when the reaction was conducted in [18O]H2O, and no tritium was released when [4-3H]F-PMP replaced PMP in the incubation. Interestingly, the pK(a) of the ring nitrogen (N-1) of F-PMP was found to be 2.91, a value drastically altered from the 8.74 of PMP itself. Since the catalytic role of B6 coenzymes is to act as an electron sink, storing the electrons that are later used for the cleavage and/or formation of covalent bonds, protonation at N-1 is clearly essential, as it allows the formation of a salt bridge/hydrogen bond with an active site aspartate residue and also enhances the electron-withdrawing capability of the pyridine ring. Because F-PMP is not expected to exist in the pyridinium form at neutral pH, its ability to promote 4'-H abstraction is hampered since the resulting anion cannot be delocalized by the cofactor. Although incubation of E1-E3 with this new coenzyme B6 analog fails to provide additional support for the mechanism of this unique deoxygenation process, the results reported herein, along with those deduced from studies of other 3-substituted PLP derivatives, illustrate the importance of having an intact 3-OH group of the coenzyme in PLP/PMP dependent catalysis.
- Pieper,Yang,Zhou,Liu
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Read Online
- Synthesis and physico-chemical properties of homoleptic copper(I) complexes with asymmetric ligands as a dssc dye
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To develop low-cost and efficient dye-sensitized solar cells (DSSCs), we designed and prepared three homoleptic Cu(I) complexes with asymmetric ligands, M1, M2, and Y3, which have the advantages of heteroleptic-type complexes and compensate for their synthetic challenges. The three copper(I) complexes were characterized by elemental analysis, UV-vis absorption spectroscopy, and electrochemical measurements. Their absorption spectra and orbital energies were evaluated and are discussed in the context of TD-DFT calculations. The complexes have high VOC values (0.48, 0.60, and 0.66 V for M1, M2, and Y3, respectively) which are similar to previously reported copper(I) dyes with symmetric ligands, although their energy conversion efficiencies are relatively low (0.17, 0.64, and 2.66%, respectively).
- Hatano, Mayuka,Inomata, Tomohiko,Kawai, Yuya,Kitagawa, Takuma,Masuda, Hideki,Matsunaga, Ayaka,Ozawa, Tomohiro,Wasada-Tsutsui, Yuko
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supporting information
(2021/11/27)
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- ENHANCER OF ZESTE HOMOLOG 2 INHIBITORS
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This invention relates to novel compounds according to Formula (I) which are inhibitors of Enhancer of Zeste Homolog 2 (EZH2), to pharmaceutical compositions containing them, to processes for their preparation, and to their use in therapy for the treatment of cancers.
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Page/Page column 93
(2015/01/06)
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- Discovery and optimization of N-(3-(1,3-dioxo-2,3-dihydro-1H-pyrrolo[3,4-c] pyridin-4-yloxy)phenyl)benzenesulfonamides as novel GPR119 agonists
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The discovery and optimization of novel N-(3-(1,3-dioxo-2,3-dihydro-1H- pyrrolo[3,4-c]pyridin-4-yloxy)phenyl)benzenesulfonamide GPR119 agonists is described. Modification of the pyridylphthalimide motif of the molecule with R1 =-Me and R2 =-iPr substituents, incorporated with a 6-fluoro substitution on the central phenyl ring offered a potent and metabolically stable tool compound 22.
- Yu, Ming,Zhang, Jian,Wang, Yingcai,Zhu, Jiang,Kayser, Frank,Medina, Julio C.,Siegler, Karen,Conn, Marion,Shan, Bei,Grillo, Mark P.,Coward, Peter,Liu, Jiwen
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p. 156 - 160
(2014/01/17)
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- Practical and scalable synthesis of S1P1 receptor agonist ACT-209905
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A practical and scalable route for the fast delivery of 12 kg of S1P 1 agonist (ACT-209905) has been developed. ACT-209905 is composed of an amino pyridine group, an oxadiazole spacer, a 2-ethyl-5-methylphenol moiety and a chiral 1-amino-2-propanol side chain. The convergent synthesis consists of 16 steps with 9 isolated intermediates and is chromatography-free. Key building blocks are accessed from low-cost starting materials, such as acetone, diethyl oxalate, cyanoacetamide, and 2-ethyl-5-methyl aniline. A Negishi coupling that was troubled by the use of metal reagents and concomitant metal waste streams has been replaced by a less expensive Guareschi-Thorpe reaction to build up an amino isonicotinic acid. The chiral 1-amino-2-propanol moiety was secured by selective ring-opening of an epoxide with lithium hexamethyldisilazide as an ammonia surrogate, thus omitting the notorious double alkylated byproduct.
- Schmidt, Gunther,Reber, Stefan,Bolli, Martin H.,Abele, Stefan
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scheme or table
p. 595 - 604
(2012/07/13)
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- Construction and functionalization of fused pyridine ring leading to novel compounds as potential antitubercular agents
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A series of fused and functionalized pyridine derivatives were designed, synthesized and tested for their potential antitubercular properties. All these novel compounds were prepared by using multistep methods involving the construction of pyridine ring as a key synthetic step. Some of these compounds were found to be interesting when tested for their antitubercular properties in vitro and one of them appeared as an attractive and potential antitubercular agent.
- Dulla, Balakrishna,Wan, Baojie,Franzblau, Scott G.,Kapavarapu, Ravikumar,Reiser, Oliver,Iqbal, Javed,Pal, Manojit
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supporting information; experimental part
p. 4629 - 4635
(2012/07/31)
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- AROMATIC COMPOUNDS AND METAL COMPLEXES THEREOF
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Provided are aromatic compounds and metal complexes thereof which may be useful treating various forms of proliferative diseases, such as cancer. In some instances, the metal complexes thereof are relatively stable, and may be suitable for oral administra
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Page/Page column 65-66
(2012/12/13)
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- 6,6′-Dimethyl-2,2′-bipyridine-4-ester: A pivotal synthon for building tethered bipyridine ligands
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We describe an efficient and scalable synthesis of 4-carbomethoxy-6,6′-dimethyl-2,2′-bipyridine starting from easily available substituted 2-halopyridines and based on the application of modified Negishi cross-coupling conditions. This compound is a versatile starting material for the synthesis of 4-functionalized 2,2′-bipyridines bearing halide, alcohol, amine, and other functionalities, suitable for conjugation to biological material (2a-c, 3a-g). The utility of this compound in the construction of more complex architectures was further demonstrated by the synthesis of two bifunctional lanthanide chelators; an open chain ligand based on one 2,2′-bipyridine unit and a cryptand based on three 2,2′-bipyridine units [N2(bpy)3COOMe]. In the field of luminophoric biolabels, the photophysical properties of the corresponding Eu(III) cryptate are reported.
- Havas, Fabien,Leygue, Nadine,Danel, Mathieu,Mestre, Béatrice,Galaup, Chantal,Picard, Claude
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experimental part
p. 7673 - 7686
(2009/12/06)
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- Pyridone esters as inotropic agents
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Described are compounds of the formula STR1 wherein R is hydrogen, lower alkyl, halo, cyano, hydroxy, amino, lower alkylamino, --CH2 NH2, --CH2 OH or --COOR"; R' is hydrogen, lower cycloalkyl or lower alkyl; R' is lower alkenyl, lower alkynyl, lower cycloalkyl, --(W)n Y wherein W is straight or branched chain lower alkyl or lower alkenyl, n is 0 to 5, and Y is Ar, lower cycloalkyl, lower alkenyl, lower alkynyl, --COOZ wherein Z is lower alkyl, STR2 or NAB wherein A and B are, independently, lower alkyl, benzyl or substituted benzyl, and Ar is 2, 3 or 4-pyridyl, pyridazinyl, pyrimidinyl, quinolyl, isoquinolyl, phthalazinyl, quinazolinyl, thiazolyl, phenyl, benzyl, furyl, tetrahydrofuryl or thienyl, unsubstituted or substituted with lower alkyl, lower alkoxy, halo, amino, or --CF3 ; R"' is --COOR", STR3 and X is oxygen or nitrogen; or a pharmaceutically acceptable salt thereof, and their use in the treatment of impaired ventricular myocardial contractility. The compounds exhibit cardiotonic activity.
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- Pyridone esters as inotropic agents
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Described are compounds of the formula STR1 wherein R is hydrogen, lower alkyl, halo, cyano, hydroxy, amino, lower alkylamino, --CH2 NH2, CH2 OH or COOR"; R' is hydrogen, lower cycloalkyl or lower alkyl; R" is lower alkyl or --CH2 Ar wherein Ar is phenyl, substituted phenyl, furan or thiophene; R'" is COOR", STR2 and x is oxygen or nitrogen; or a pharmaceutically acceptable salt thereof and their use in the treatment of impaired ventricular myocardial contractility. The compounds exhibit cardiotonic activity.
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