| abstract |
The present invention relates to a method for the preparation of citalopram comprising reaction a compound of formula (I) n n n with a compound having the formula n n n wherein X is a suitable leaving group and R is —CH 2 —O—Pg, —CH 2 —NPg 1 P g2 , —CH—N(CH 3 ) 2 , —CH(OR 1 )(OR 2 ) —C(OR 4 )(OR 5 )(OR 6 ), —COOR 3 , —CH 2 —CO—NH 2 , —CH═CHR 7 and —CONHR 8 , wherein Pg is a protection group for an alcohol group, Pg 1 and Pg 2 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; n to form a compound of the formula n n n 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. |