METHOD FOR PREPARING INTERMEDIATE OF SITAGLIPTIN AND INTERMEDIATES USED THEREIN

摘要

PURPOSE: A method for preparing a sitagliptin intermediate is provided to efficiently prepare (3R)-3-t-butoxycarbonylamino-4-(2,4,5-trifluorophenyl)-butyric acid, an main intermediate of sitagliptin, using commercially easily available chiral oxirane. CONSTITUTION: A method for preparing (3R)-(3-t-butoxycarbonylamino-4-(2,4,5-trifluorophenyl)-butyric acid) comprises the steps of: (i) reacting a compound of chemical formula 2 with trifluorophenyl magnesium halide to prepare a compound of chemical formula 3; (ii) performing Mitsunobu reaction of the compound of chemical formula 3 to prepare a compound of chemical formula 4; (iii) removing an amine protecting group of the compound of chemical formula 4 to prepare a compound of chemical formula 5; (iv) protecting an amine group of the compound of chemical formula 5 to prepare a compound of chemical formula 6; and (v) converting an alkene group of chemical formula 6 into carboxylic acids.