- The development of a new class of inhibitors for betaine-homocysteine S-methyltransferase
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Betaine-homocysteine S-methyltransferase (BHMT) is an important zinc-dependent methyltransferase that uses betaine as the methyl donor for the remethylation of homocysteine to form methionine. In the liver, BHMT performs to half of the homocysteine remethylation. In this study, we systematically investigated the tolerance of the enzyme for modifications at the "homocysteine" part of the previously reported potent inhibitor (R,S)-5-(3-amino-3-carboxy-propylsulfanyl)-pentanoic acid (1). In the new compounds, which are S-alkylated homocysteine derivatives, we replaced the carboxylic group in the "homocysteine" part of inhibitor 1 with different isosteric moieties (tetrazole and oxadiazolone); we suppressed the carboxylic negative charge by amidations; we enhanced acidity by replacing the carboxylate with phosphonic or phosphinic acids; and we introduced pyrrolidine steric constraints. Some of these compounds display high affinity toward human BHMT and may be useful for further pharmacological studies of this enzyme. Although none of the new compounds were more potent inhibitors than the reference inhibitor 1, this study helped to completely defi ne the structural requirements of the active site of BHMT and revealed the remarkable selectivity of the enzyme for homocysteine.
- Pi?ha, Jan,Vaňek, Václav,Budě??sińsky, Milo?,Mlad?ková, Jana,Garrow, Timothy A.,Ji??acek, Ji??i
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p. 256 - 275
(2013/10/01)
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- Reaction of epoxyketones with hydrogen peroxide - Ethane-1,1- dihydroperoxide as a surprisingly stable product
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Reaction of epoxyketones with hydrogen peroxide, ethane-1,1-dihydroperoxide as a stable product was reported. Triacetone triperoxide and methylhydroperoxide were reported as highly explosive compounds. Thermogravimetric investigations showed decomposition in the temperature range 60-130°C with the highest decomposition rate at about 105°C. Using differently substituted epoxyketones as reactants, it was able to isolate and characterize propane-1,1-dihydroperoxide. Epoxyketones can also be attacked by H2O2 at the carbonyl C atom and at both epoxy C atoms as electrophilic centers. Initial results revealed that the acid-catalyzed reaction of 5- and 7-ring homologues 1 (n=0,2) with H2O2 runs similarly. They also show a lower tendency to form the geminal dihydroperoxide.
- Hamann, Hans-Juergen,Bunge, Alexander,Liebscher, Juergen
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scheme or table
p. 6849 - 6851
(2009/07/10)
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- Design, synthesis, and antipicornavirus activity of 1-[5-(4-arylphenoxy) alkyl]-3-pyridin-4-ylimidazolidin-2-one derivatives
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A series of pyridylimidazolidinone derivatives was synthesized and tested in vitro against enterovirus 71 (EV71). On the basis of compound 33 (DBPR103), introduction of a methyl group at the 2- or 3-position of the linker between the imidazolidinone and the biphenyl resulted in markedly improved antiviral activity toward EV71 with IC50 values of 5.0 nM (24b) and 9.3 nM (14a), respectively. Increasing the branched chain to propyl resulted in a progressive decrease in activity, while inserting different heteroatoms entirely rendered the compound only weakly active. The introduction of a bulky group (cyclohexyl, phenyl, or benzyl) led to loss of activity against EV71. The 4-chlorophenyl moiety in 14a was replaced with bioisosteric groups such as oxadiazole (28a-d) or tetrazole (32a,b), dramatically improving anti-EV71 activity and selectivity indices. Compounds 14a, 24b, 28b, 28d, and 32a exhibited a strong activity against lethal EV71, and no apparent cellular toxicity was observed. Three of the more potent imidazolidinone compounds, 14a, 28b, and 32b, were subjected to a large group of picornaviruses to determine their spectrum of antiviral activity.
- Chang, Chih-Shiang,Lin, Ying-Ting,Shih, Shin-Ru,Lee, Chung-Chi,Lee, Yen-Chun,Tai, Chia-Liang,Tseng, Sung-Nien,Chern, Jyh-Haur
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p. 3522 - 3535
(2007/10/03)
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- Phase transfer catalysis by tetraethylammonium bromide: Nucleophilic opening of anhydrides using potassium superoxide in aprotic medium
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Tetraethylammonium superoxide, generated in situ by the phase transfer reaction of potassium superoxide and tetraethylammonium bromide, brings about a clean cleavage of various anhydrides, particularly those with high molecular weight in dry dimethylformamide. As an outcome, succinic anhydride 1; glutaric anhydride 2; 3,3-dimethylglutaric anhydride 3; phthalic anhydride 4; diphenic anhydride 5; 1,2,3,4-tetrahydro-9-oxo-1,4-ethanonaphthalene-2,3- endo-dicarboxylic anhydride 6: 1,4,5,6,7,7-hexachloro-5-norbomene-2,3- dicarboxylic anhydride 7; endo-bicyclo [2.2.1] heptan-2-one-5,6-dicarboxylic anhydride 8; cis-5-norbornene-endo-2,3-dicarboxylic anhydride 9 and trans- 1,2-cyclohexane dicarboxylic anhydride 10 have been transformed into their corresponding dicarboxylic acids in fairly good yields. The report demonstrates the applicability of tetraethylammonium bromide as a phase transfer catalyst for efficient superoxide studies.
- Singh, Sundaram,Shukla, Ajay Kumar,Singh, Krishna Nand
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p. 1184 - 1188
(2007/10/03)
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- THE REACTION OF CYCLIC β-DIKETONES WITH TRIFLUOROMETHYLSULPHENYL CHLORIDE
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The reactions of cyclic β-diketones with trifluoromethylsulphenyl chloride were carried out to give the corresponding CF3S-substituted derivatives.Oxidation of the CF3S-substituted dimedone led to ring cleavage.The CF3SO2-substituted dimedone was prepared by reaction of trifluoromethylsulphonyl chloride with the metallated β-diketone.
- Popov, V.I.,Haas, A.,Lieb, M.
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p. 131 - 136
(2007/10/02)
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- Mild Carbon-Carbon Bond Cleavage of Carbonyl Compounds using Pentafluoroiodobenzene Bis(trifluoroacetate)
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Acetophenones, α-hydroxyacetophenones, deoxybenzoin, benzoin, and benzil are cleaved oxidatively with pentafluoroiodobenzene bis(-trifluoroacetate) in wet benzene at room temperature to give the corresponding benzoic acids; cyclohexanone and dimedone are cleaved to give the diacids adipic acid and 3,3-dimethylglutaric acid, respectively.
- Moriarty, Robert M.,Prakash, Indra,Penmasta, Raju
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p. 202 - 203
(2007/10/02)
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- Process for the production of 3,3-dimethylglutaric acid or its esters
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Process for the production of 3,3-dimethylglutaric acid or its esters from dimedone. Dimedone is converted with ozone into an ozone-addition product. The latter is converted by hydrolysis into 3,3-dimethylglutaric acid or by alcoholysis into one of its esters.
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- Geminate-Substituted Cyclopentadienes. 1. Synthesis of 5,5-Dialkylcyclopentadienes via 4,4-Dialkylcyclopent-2-en-1-ones.
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A synthetic route for the preparation of 5,5,-dialkylcyclopentadienes (1) via 4,4-dialkylcyclopent-2-en-1-ones (3) is described.Beginnig with ketones (in which the two carbonyl substituents will become the two alkyl groups in the title compounds), the route traverses the Guareschi imides 5, 3,3-dialkylglutaric acids 4 and their ethyl esters 7, masked acyloins 8, cyclopentenones 3, alkohols 9, and bromides 10 to reach the dienes 1.Physical properties of five such derivates 1 and 3 (dimethyl, methylethyl,diethyl, methyl-n-propyl, and methylisopropyl) are presented.
- Holder, Richard W.,Daub, John P.,Baker, Wesley E.,Gilbert, Raymond H,Graf, Norman A.
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p. 1445 - 1451
(2007/10/02)
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