| 摘要 |
<p>The present invention relates to an improved and industrially advantageous process for the preparation of (1S, 4S, 5S) -4-bromo-6-oxabicyclo [3.2.1] octan-7-one represented by the following formula (I) which is a key intermediate in the synthesis of edoxaban, a compound that exhibits an inhibitory effect on activated blood coagulation factor X (also referred to as activated factor X or FXa), and is useful as a preventive and/or therapeutic drug for thrombotic diseases. The process includes reacting (1S) -cyclohex-3-ene-1-carboxylic acid of formula (II) with a brominating agent selected from the group consisting of N-bromosuccinimide or 1, 3-dibromo-5, 5-dimethylhydantoin in the presence of a base selected from calcium oxide or calcium hydroxide in a solvent selected from the group comprising of dichloromethane, toluene, tetrahydrofuran, ethy1 acetate, hexanes, cyclopentyl methyl ether (CPME) or a mixture thereof to get ( 1S, 4S, 5S) -4-bromo-6-oxabicyclo [3.2.1] octan-7-one of formula (I).</p> |
