Abstract:
PURPOSE: A method for preparing chiral hemiesters through asymmetric ring opening reaction of meso-cyclic anhydrides is provided to ensure high value of industrial use and to reuse it by a basic acid-base distillation method. CONSTITUTION: A method for preparing chiral hemiesters through asymmetric ring opening reaction of meso-cyclic anhydrides comprises a step for reacting meso-cyclic anhydride with alcohol by using organic catalysts represented by chemical formula 1 or chemical formula 2 in the presence of an organic solvent. In the formulae, X is O or S and R is ethyl or vinyl. The chemical formula 1 has dihydro quinine or quinine as a starting material. The chemical formula 2 has dihydro quinine or quinine as a starting material.
Abstract:
PURPOSE: A method for manufacturing chiral hemiester using bifunctional organic catalys is provided to synthesize chiral compound which stereochemically or pharmaceutically useful. CONSTITUTION: A bifunctional organic catalyst is denoted by chemical formula 1 or 2. In chemical formula 1 or 2, Ar is 4-11 reduction aryl; R2-R8 are independently hydrogen, alkyl of 1-12 carbon atoms, alkenyl of 2-12 carbon atoms, alkenyl of 2-12 carbon atoms, alkoxy of 1-12 carbon atoms, or aryl of 4-11 reduction; and P is non-reactive polymer. The non-reactive polymer is polystyrene, polyethylene, or polypropylene. A chiral hemiester is prepared by reacting prochiral compound or meso-cyclic acid anhydride with nucleophile under the presence of a compound of chemical formula 1 or 2. The nucleophile is alcohol, thiol, or amine.
Abstract:
PURPOSE: A method for synthesizing bifunctional cinchona alkaloid catalyst is provided to ensure low toxicity, and chemical stability, and synthesize chiral hemiester having various structures in a short time. CONSTITUTION: A bifunctional cinchona alkaloid catalyst is denoted by chemical formula 1 or 2. A chiral hemiester is produced by reacting a prochiral or meso-cyclic acid anhydride with nucleophile in organic solvent under the presence of the bifunctional cinchona alkaloid catalyst. The nucleophile is alcohol or thiol. The organic solvent is dimethoxyethane, ethylvinyl ether, methyl t-butyl ether, diethyl ether, diisopropyl ether, tetra hydro furan or dioxane.