- Synthesis of Unprotected 2-Arylglycines by Transamination of Arylglyoxylic Acids with 2-(2-Chlorophenyl)glycine
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The transamination of α-keto acids with 2-phenylglycine is an effective methodology for directly synthesizing unprotected α-amino acids. However, the synthesis of 2-arylglycines by transamination is problematic because the corresponding products, 2-arylglycines, transaminate the starting arylglyoxylic acids. Herein, we demonstrate the use of commercially available l-2-(2-chlorophenyl)glycine as the nitrogen source in the transamination of arylglyoxylic acids, producing the corresponding 2-arylglycines without interference from the undesired self-transamination process.
- Inada, Haruki,Shibuya, Masatoshi,Yamamoto, Yoshihiko
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p. 11047 - 11059
(2020/10/12)
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- Method for continuously and quickly preparing DL-phenylglycine and analogue thereof
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The invention provides a method for continuously and quickly preparing DL-phenylglycine and an analogue thereof. The method comprises the steps of adding 2-hydroxyl-phenylacetonitrile and an analoguethereof (cyanohydrin for short) and an aqueous ammonium bicarbonate solution into a microchannel reactor for a reaction, controlling the reaction temperature to be 80-130 DEG C, and controlling the reaction pressure to be 0.5-2.0 MPa, wherein the standing time of the reactants in a microchannel is 1-8 min, and an aqueous solution of 5-phenyl-hydantoin and an analogue thereof (hydantoin for short)is obtained; adding the hydantoin and alkali into the microchannel reactor for a reaction, controlling the reaction temperature to be 120-200 DEG C, and controlling the reaction pressure to be 1.0-3.5MPa, wherein the standing time of the reactants in the microchannel is 1-8 min, and then a saline solution of phenylglycine and an analogue thereof is obtained; conducting acidification neutralization and crystallization to obtain the phenylglycine and the analogue thereof. According to the method, the microchannel reactor is adopted, the reaction time is greatly shorted, the reaction speed is increased, pyrolysis and polymerization of the cyanohydrin are reduced, no by-products are generated, the products are high in yield, clean and environmentally friendly, and the production cost is lowered.
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Paragraph 0037-0039
(2019/07/04)
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- PLATELET ADP RECEPTOR INHIBITORS
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Compounds are provided which are useful as platelet ADP receptor inhibitors, for treating thrombosis and for reducing the likelihood and/or severity of a secondary ischemic event in a patient.
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Page/Page column 55
(2008/06/13)
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- UREAS AS FACTOR XA INHIBITORS
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The present invention is directed to compounds represented by Formula (I) and pharmaceutically acceptable salts, solvates, hydrates, and prodrugs thereof which are inhibitors of Factor Xa. The present invention is also directed to and intermediates used in making such compounds, pharmaceutical compositions containing such compounds, methods to prevent or treat a number of conditions characterized by undesired thrombosis and methods of inhibiting the coagulation of a blood sample.
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Page/Page column 87
(2010/11/08)
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- Mechanism of the Racemization of Amino Acids. Kinetics of Racemization of Arylglycines
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In a study of the rates of racemization of substituted arylglycines at pH 10, the Hammett ? value was found to be surprisingly low, 1.15, suggesting a concerted reaction or charge stabilization in a manner other than by the substituent.The rate of methine hydrogen exchange was, however, the same as the rate of racemization, which argues against a concerted reaction mechanism.A pH profile study demonstrated that the most reactive species was the zwitterion +NH3CH(C6H5)CO2-> in basic media.The racemization reaction showed general-base catalysis when the buffer concentration was changed at constant ionic strength.Within the aryl series, the entropy of activation was more significant than the enthalpy of activation.The ΔS(excit.) ranged from -24.5 to +29.0 eu, while ΔH(excit.) values ranged from 19.9 to 20.4 kcal.Racemization of arylglycines followed reversible first-order kinetics similar to that found for aliphatic amino acids in solution.The extent of racemization was studied as a function of pH.The details of the mechanism of this reaction are presented in light of these data.
- Smith, Grant Gill,Sivakua, Thipamon
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p. 627 - 634
(2007/10/02)
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- 7-α-Amino-substituted acylamino-3-(1-carboxymethyltetrazol-5-ylthiomethyl)-3-cephem-4-carboxylic acids
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Certain 7-acylamido-3-(1-carboxy-loweralkyl-tetrazol-5-ylthiomethyl)-3-cephem-4-carboxylic acids and their salts and easily hydrolyzed esters of the 4-carboxyl group were synthesized and found to be potent antibacterial agents which exhibited good aqueous solubility. In a preferred embodiment the 7-substituent was 2'-aminomethylphenylacetamido.
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