- Palladium-Catalyzed Asymmetric Allylic Alkylation of 4-Substituted Isoxazolidin-5-ones: Straightforward Access to β2,2-Amino Acids
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We report here an unprecedented and highly enantioselective palladium-catalyzed allylic alkylation applied to 4-substituted isoxazolidin-5-ones. Ultimately, the process provides a straightforward access to β2,2-amino acids bearing an all-carbon quaternary stereogenic center in great yields and a high degree of enantioselectivity.
- Nascimento de Oliveira, Marllon,Arseniyadis, Stellios,Cossy, Janine
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supporting information
p. 4810 - 4814
(2018/03/21)
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- The synthesis method of intermediate sodium card Xilin
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The invention discloses a synthesis method of ticarcillin disodium intermediate 2,2-dimethyl-5-(3-thienyl)-4,6-dione-1,3-dioxane. The synthesis method comprises the following steps: mixing thiophenemalonic acid with acid anhydride at the temperature of 10 DEG C to 60 DEG C, and then adding dimethyl sulfoxide; and adding acetone under the action of an inorganic acid, and then carrying out hydrolysis under acidic conditions to obtain the intermediate. The synthesis method has the advantages that: the operation is simple and convenient, the environmental pollution is small, the yield is more than 80% and the purity is up to 99.8%.
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Paragraph 0029; 0031; 0032; 0033; 0035; 0037
(2018/07/10)
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- Intermediates for preparing α-carboxy-α-(3-thienyl)penicillin and cephalosporin derivatives
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A new process is disclosed for the preparation of alpha-carboxy-alpha-phenyl(or 3-thienyl)penicillin and cephalosporin derivatives. The process comprises reacting a 1.3-dioxane-4.6-dione derivative with the desired penicillanic or cephalosporanic acid derivative.
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