42783-36-8Relevant articles and documents
Organic bifunctional catalyst and preparation method thereof as well as stereoregular biodegradable polyester and preparation method thereof
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Paragraph 0101-0104, (2021/07/10)
The invention relates to an organic bifunctional catalyst and a preparation method thereof, and stereoregular biodegradable polyester and a preparation method thereof. The organic bifunctional catalyst disclosed by the invention is obtained by reacting isocyanate or isothiocyanate with a pyridylamine compound. According to the catalyst, an O-carboxyl intracyclic anhydride monomer and a pyridine nucleophilic addition monomer of an amino acid source are activated by thiourea, and controllable ring opening polymerization can be performed on an OCA monomer under a mild condition by utilizing an amplification effect of adjacent groups, so that functional polyester with high isotacticity and controllable molecular weight is prepared. The solvent used for polymerization can be chloroform, toluene, dichloromethane and the like, the polymerization temperature range is 25-50 DEG C, and the stereoregularity is adjustable between 60% and 90%. Under the polymerization condition, the monomer conversion rate can reach 99% within 24-48 hours. The molecular weight of the obtained polyester is controllable, and the melting point reaches up to 150 DEG C. The molecular weight of the polyester is changed between 20,000 and 100,000, and the polyester has a wide prospect for industrial application.
Kinetic resolutions of chiral 2-and-3-substituted carboxylic acids
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, (2008/06/13)
One aspect of the present invention relates to a method for the kinetic resolution of racemic and diastereomeric mixtures of chiral compounds. The critical elements of the method are: a non-racemic chiral tertiary-amine-containing catalyst; a racemic or diastereomeric mixture of a chiral substrate, e.g., a cyclic carbonate or cyclic carbamate; and a nucleophile, e.g., an alcohol, amine or thiol. A preferred embodiment of the present invention relates to a method for achieving the kinetic resolution of racemic and diastereomeric mixtures of derivatives of α- and β-amino, hydroxy, and thio carboxylic acids. In certain embodiments, the methods of the present invention achieve dynamic kinetic resolution of a racemic or diastereomeric mixture of a substrate, i.e., a kinetic resolution wherein the yield of the resolved enantiomer or diastereomer, respectively, exceeds the amount present in the original mixture due to the in situ equilibration of the enantiomers or diastereomers under the reaction conditions prior to the resolution step.
Cephalosporin derivatives
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, (2008/06/13)
A series of novel 7-(Dα-aminophenylacetamido)- and 7-(D-α-hydroxyphenylacetamido)- Δ3 -cephem derivatives have been prepared wherein a heterocyclic thiomethyl moiety is located at the 3-position of the molecule. These compounds are useful as antibacterial agents for the treatment of diseases caused by Gram-positive and Gram-negative bacteria. Preferred members include 7-(D-α-hydroxyphenylacetamido)-3-(3-carbamoyl-1,2,4-triazol-5-yl)thiomethylceph-3-em-4-carboxylic acid and 7-(D-α-hydroxyphenylacetamido)-3-(2-carboxymethoxy-methyl-1,3,4-thiadiazol-5-yl)thiomethylceph-3-em-4-carboxylic acid. Alternative methods of preparation are provided for these compounds, including various synthetic routes leading to the required novel heterocyclic thiol intermediates.
