- Exploring sources of catalysis in the basic elimination of 5-nitrobenzisoxazole
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A C-shaped, bifunctional host with a highly preorganized cleft was used as a host system to investigate the sources of catalysis in the base-promoted conversion of 5-nitrobenzisoxazole to 2-cyano-5-nitrophenolate. Kinetic studies with compounds that partly conserve structural elements of the host suggest that π-stacking interactions and solvation effects mainly contribute to the observed rate acceleration of the host compared to the acetate promoted reaction.
- Hannak, Renate B.,Rojas, Christian M.
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- COMPOUNDS AND METHODS FOR THE TREATMENT OF VIRUSES AND CANCER
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The present invention relates to compounds according to the formula I: Where Ra is H or an optionally OH-substituted C1-C3 alkyl; R1 is OR1, an optionally substituted C4-12 carbocyclic group which may be saturated or unsaturated (including aromatic) or an optionally substituted heterocyclic group; R1 is an optionally substituted C1-C14 hydrocarbyl group or an optionally substituted heterocyclic group;; R2 , R3 and R4 are each independently H, an optionally substituted C1-C4 alkyl group (preferably CH3, CH2CH3 or CF3), halogen (preferably F, Cl, Br), OR, CN, NO2, a C1-C6 thioether, a C1-C6 thioester group, an optionally substituted CO2R group, an optionally substituted COR group or an optionally substituted OCOR group (preferably R4 is H); R is H or an optionally substituted C1-C6 alkyl group; RHET is an optionally substituted heterocyclic group; and pharmaceutically acceptable salts, solvates or polymorphs thereof.
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Page/Page column 24; 25
(2010/11/26)
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- Optimization of diarylamines as non-nucleoside inhibitors of HIV-1 reverse transcriptase
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Following computational analyses, potential non-nucleoside inhibitors of HIV-1 reverse transcriptase have been pursued through synthesis and assaying for anti-viral activity. The general class Het-NH-Ph-U has been considered, where Het is an aromatic heterocycle and U is an unsaturated, hydrophobic group. Results for compounds with Het = 2-thiazoyl and 2-pyrimidinyl are the focus of this report.
- Ruiz-Caro, Juliana,Basavapathruni, Aravind,Kim, Joseph T.,Bailey, Christopher M.,Wang, Ligong,Anderson, Karen S.,Hamilton, Andrew D.,Jorgensen, William L.
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p. 668 - 671
(2007/10/03)
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- METHOD FOR THE PREPARATION OF FUSED HETEROCYCLIC SUCCINIMIDE COMPOUNDS AND ANALOGS THEREOF
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Fused cyclic compounds, methods of using such compounds in the treatment of nuclear hormone receptor-associated conditions such as cancer and immune disorders, and pharmaceutical compositions containing such compounds.
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- Fused heterocyclic succinimide compounds and analogs thereof, modulators of nuclear hormone receptor function
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Fused cyclic compounds, methods of using such compounds in the treatment of nuclear hormone receptor-associated conditions such as cancer and immune disorders, and pharmaceutical compositions containing such compounds.
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- Nonspecific medium effects versus specific group positioning in the antibody and albumin catalysis of the base-promoted ring-opening reactions of benzisoxazoles
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The mechanisms by which solvents, antibodies, and albumins influence the rates of base-catalyzed reactions of benzisoxazoles have been explored theoretically. New experimental data on substituent effects and rates of reactions in several solvents, in an antibody, and in an albumin are reported. Quantum mechanical calculations were carried out for the reactions in water and acetonitrile, and docking of the transition state into a homology model of antibody 34E4 and an X-ray structure of human serum albumin was accomplished. A microenvironment made up of catalytic polar groups (glutamate in antibody 34E4 and lysine in human serum albumin) surrounded by relatively nonpolar groups is present in both catalytic proteins.
- Hu, Yunfeng,Houk,Kikuchi, Kazuya,Hotta, Kinya,Hilvert, Donald
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p. 8197 - 8205
(2007/10/03)
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- On the magnitude and specificity of medium effects in enzyme-like catalysts for proton transfer
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Medium effects are normally studied by comparing the rates of reactions in different solvents. However, medium effects at the active site of enzymes differ dramatically from bulk solvents, both in their diversity (the presence of more than one type of "so
- Hollfelder,Kirby,Tawfik
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p. 5866 - 5874
(2007/10/03)
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- Exploiting subsite S1 of trypsin-like serine proteases for selectivity: Potent and selective inhibitors of urokinase-type plasminogen activator
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A nonselective inhibitor of trypsin-like serine proteases, 2-(2-hydroxybiphenyl-3-yl)-lH-indole-5-carboxamidine (1) (Verner, E.; Katz, B. A.; Spencer, J.; Allen, D.; Hataye, J.; Hruzewicz, W.; Hui, H. C.; Kolesnikov, A.; Li, Y.; Luong, C.; Martelli, A.; Radika. K.; Rai, R.; She, M.; Shrader, W.; Sprengeler, P. A.; Trapp, S.; Wang, J.; Young, W. B.; Mackman, R. L. J. Med. Chem. 2001, 44, 2753-2771) has been optimized through minor structural changes on the S1 binding group to afford remarkably selective and potent inhibitors of urokinase-type plasminogen activator (uPA). The trypsin-like serine proteases1 that comprise drug targets can be broadly categorized into two subfamilies, those with Ser190 and those with Ala190. A single-atom modification, for example, replacement of hydrogen for chlorine at the 6-position of the 5-amidinoindole P1 group on 1, generated up to 6700-fold selectivity toward the Ser190 enzymes and against the Alal90 enzymes. The larger chlorine atom displaces a water molecule (H2O1s1) that binds near residue 190 in all the complexes of 1, and related inhibitors, in uPA, thrombin, and trypsin. The water molecule, H2O1s1, in both the Ser190 or Ala190 enzymes, hydrogen bonds with the amidine N1 nitrogen of the inhibitor. When it is displaced, a reduction in affinity toward the Ala190 enzymes is observed due to the amidine N1 nitrogen of the bound inhibitor being deprived of a key hydrogen-bonding partner. In the Ser190 enzymes the affinity is maintained since the serine hydroxyl oxygen Oγser190 compensates for the displaced water molecule. Highresolution crystallography provided evidence for the displacement of the water molecule and validated the design rationale. In summation, a novel and powerful method for engineering selectivity toward Ser190 proteases and against Ala190 proteases without substantially increasing molecular weight is described.
- Mackman,Katz,Breitenbucher,Hui,Verner,Luong,Liu,Sprengeler
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p. 3856 - 3871
(2007/10/03)
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- A preparative, spectroscopic anti equilibrium study of some phenyl-2- thiazoline fluorophores for aluminium(III) detection
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As part of a study of fluorophores for selective Al3+ detection and of potential use in the study of intracellular Al3+, the preparative, UV- visible and fluorescence spectroscopic, and Al3+ coordination characteristics of five ligands containing the conjugated phenolic substituted thiazoline chromophore of the natural siderophore, pyochelin, 2- [2-(2-hydroxyphenyl)-4,5-dihydro-1,3-thiazol-4-yl]-3-methyl-1,3-thiazolane-4- carboxylic acid) 1, are reported. The five ligands are 2-(2-hydroxyphenyl)- 4,5-dihydro-1,3-thiazole-4-carboxylic acid, 2, 2-(4,5-dihydro-1,3-thiazol-2- yl)phenol, 3, 4-bromo-2-(4,5-dihydro-1,3-thiazol-2-yl)phenol, 4, 2-(4,5- dihydro-1,3-thiazol-2-yl)-5-nitrophenol, 5, and 2-(4,5-dihydro-1,3-thiazol-2- yl)-4-nitrophenol, 6. All form stable binary Al3+ complexes in 75% methanol and 25% water in the case of 2, and 73.2% methanol, 24.4% water and 2.4% N,N- dimethylformamide in the case of 3-6, and exhibit substantial UV-visible absorbance changes on coordination. However, while 2, 3 and 4 fluoresce strongly when coordinated to Al3+, 5 and 6 do not, probably because their fluorescence is quenched through a twisted intramolecular charge transfer process. All five ligands show selectivity in complexing for Al3+ over other metal ions and, in the case of 2, 3 and 4, represent an initial stage in the development of Al3+ specific fluorophores for biological use.
- Lambert, Stephanie G.,Taylor, Jo-Anne M.,Wegener, Kate L.,Woodhouse, Susan L.,Lincoln, Stephen F.,Ward, A. David
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p. 541 - 546
(2007/10/03)
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- Catalysis of 3-carboxy-1,2-benzisoxazole decarboxylation by hydrophobic antibody binding pockets
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Monoclonal antibodies were generated against a 3-phenyl-1,2-benzisoxazole derivative and shown to catalyze the solvent-sensitive decarboxylation of 3-carboxy-1,2-benzisoxazoles. In addition to rate accelerations up to 2300-fold over background, the antibo
- Hotta, Kinja,Kikuchi, Kazuja,Hilvert, Donald
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p. 2183 - 2191
(2007/10/03)
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- An indirect chaotropic mechanism for the stabilization of helix conformation of peptides in aqueous trifluoroethanol and hexafluoro-2- propanol
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A revised indirect mechanism is proposed for the effect of 2,2,2- trifluoroethanol on peptide conformation (TFE effect) that suggest tighter solvent shells in pure water for helical states than random coil states. The alcoholic cosolvent stabilizes the he
- Walgers, Richard,Lee, Tony C.,Cammers-Goodwin, Arthur
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p. 5073 - 5079
(2007/10/03)
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- Regioselective cleavage reaction of the aromatic methylenedioxy ring. V. Cleavage with sodium alkoxides-alcohols, potassium tert-butoxide-alcohols, dimsyl anion-methyl alcohol, metallic sodium-alcohols, and sodium cyanide in dipolra aprotic solvents
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The reaction of aromatic methylenedioxy compounds containing electron-withdrawing groups with dimsyl anion-methyl alcohol, potassium tert-butoxide-alcohols, and metallic sodium-alcohols in dimethyl sulfoxide (DMSO), and with sodium alkoxides-alcohols in hexamethylphosphoramide, gave 3- and 4-hydroxybenzene derivatives in good yield by regioselective attack of the alkoxide ions on the methylenedioxy ring. The formation mechanism of alkoxide ions and the effect of DMSO in the cleavage reaction of the methylenedioxy ring are discussed on the basis of proton nuclear magnetic resonance (1H-NMR) spectra. The reactions of aromatic methylenedioxy compounds (3 and 22) with sodium cyanide in dipolar aprotic solvents gave 4-cyano-3-hydroxybenzene derivatives (23 and 24) by regioselective attack of the cyanide ion on the methylenedioxy ring. The reactions of aromatic methylenedioxy compounds (28-30) containing no electron-withdrawing group with MeONa-MeOH in dipolar aprotic solvents gave non-regioselective cleavage products (31 and 34).
- Imakura,Okimoto,Konishi,Hisazumi,Yamazaki,Kobayashi,Yamashita
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p. 1691 - 1696
(2007/10/02)
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- Applicaton of Stepwise Self-Association Models for the Analysis of Reaciton Rates in Aggregates of Tri-n-octylalkylammonium Salts
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Tri-n-octylalkylammonium salts, 1, form small, polydisperse aggregates and do not have a critical micelle concentration.Rate enhancements of decarboxylation of 6-nitrobenzisoxazolecarboxylate ion in 1c (alkyl = Et) and 1e (alkyl = 2-hydroxyethyl) and dephosphorylation of 2,4-dinitrophenyl phosphate were analyzed by using a one-parameter self-association scheme of aggregation.Reacitons of 2,4-dinitrochlorobenzene, bis(2,4-dinitrophenyl) phosphate and p-nitrophenyl diphenyl phosphate with 1e at high pH were analyzed by using a similar model.Better fits of the data were obtained than with schemes based on a simple mass-action model.
- Biresaw, Girma,Bunton, Clifford A.
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p. 5854 - 5858
(2007/10/02)
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- Decarboxylation of 6-Nitrobenzisoxazole-3-carboxylate Anion Catalyzed by Systematically Quaternized Poly(4-vinylpyridines). "Average Side-Chain Length" as a Useful Index for Relativ Hydrophobicity of the Polymer Domain
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In an attempt to find a relation between the structure of water-soluble polymers and their catalytic efficiencies, decarboxylation (30 deg C, aqueous medium) of the title carboxylate ion (1) was used as a kinetic probe.The polymers employed were poly(viny
- Shinkai, Seiji,Hirakawa, Shin-ichi,Shimomura, Masatsugu,Kunitake, Toyoki
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p. 868 - 872
(2007/10/02)
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