AN IMPROVED PROCESS FOR THE PREPARATION OF LURASIDONE AND ITS INTERMEDIATE

摘要

The present invention provides an improved process for preparation of the substantially pure (3a R,7a R)-4'-(benzo[d]isothiazol-3-yl)octahydrospiro[isoindole-2,1'-piperazin]-1'-ium methanesulfonate (referred to as compound-II), which is useful as a key intermediate for the synthesis of lurasidone ((3a R,4S,7R,7a S)-2-{(1R,2R)-2-[4-(1,2-benzisothiazol-3- yl)piperazin-1ylmethyl] cyclohexylmethyl}hexahydro-4,7-methano-2H-isoindole-1,3-dione). The process comprises reaction of the compound-III (as described herein) with the compound-IV (as described herein) in the presence of a solvent mixture selected from an alcohol and water; and a base The improved process for the preparation of compound II provides the product with total amount of unreacted compound-IV as impurity in less than 0.06 % and the product with HPLC purity as ≥ 99.8%. The process further refers purification of Lurasidone hydrochloride, wherein the product contains the residual acetone < 5000 ppm.