METHOD FOR THE PREPARATION OF CITALOPRAM

摘要

The present invention relates to a method for the preparation of citalopram comprising reaction a compound of formula (I) with a compound having formula (II) wherein X is a suitable leaving group and R is -CH2-O-Pg, -CH2-NPg1Pg2 , -CO-N(CH3)2, -CH(OR<1>)(OR<2>), -C(OR<4>)(OR<5>)(OR<6>), -COOR<3>, -CH2-CO-NH2, -CH=CHR<7> and -CONHR<8> wherein Pg is a protection group for an alcohol group, Pg1 and Pg2 are protection groups for an amino group, R<1> and R<2> are independently selected from alkyl, alkenyl, alkynyl and optionally alkyl substituted aryl or aralkyl groups or R<1> and R<2> together form a chain of 2 to 4 carbon atoms, each of R<3>, R<4>, R<5>, R<6> and R<7> are independently selected from alkyl, alkenyl, alkynyl and optionally alkyl substituted aryl or aralkyl and R<8> is hydrogen or methyl; to form a compound of formula (III) wherein R is as defined above; followed by conversion of the group R to form a dimethylaminomethyl group and isolation of citalopram base or a pharmaceutically acceptable salt thereof.