Patent ID: 8362279

Claim:
A process for the preparation of a compound of Formula-1, the process comprising: a) reacting a compound of Formula-2 with dimethylamine hydrochloride in the presence of paraformaldehyde in an alcohol solvent to give a mixture of a compound of Formula-4 and a compound of Formula 4I, and separating the mixture of the compound of Formula-4 and the compound of Formula-4I from the alcohol solvent to obtain a separated mixture of the compound of Formula-4and the compound of Formula-4I, b) heating the separated mixture in an alcohol solvent, with or without water, a ketone solvent, with or without water, or a mixture thereof, to reflux, cooling the separated mixture, and isolating the compound of Formula-4 from the separated mixture of the compound of Formula-4 and the compound of Formula-4I, c) reducing the compound of Formula-4 isolated in step b) with an alkali metal borohydride in a C 1 -C 4 alcohol, and isolating a compound of Formula-5 in a non-polar solvent, or a mixture thereof, d) resolving the compound of Formula-5 with a chiral acid in an ester solvent, thereby forming a salt of the compound of Formula-5, then separating the R-isomer of the salt from the S-isomer of the salt in a second ester solvent, further treating the S-isomer of the salt with a weak inorganic base in a chlorinated or third ester solvent to yield a compound of Formula-6, e) reacting the compound of Formula-6 with a compound of Formula-7, in the presence of an alkali base in a polar aprotic solvent to form a condensed compound, demethylating the condensed compound to form duloxetine and reacting duloxetine with oxalic acid to form a compound of Formula-8, f) converting the compound of Formula-8 into the compound of Formula-1 by adjusting the pH of the reaction mixture to between 2 to 4 using a source of hydrochloric acid in an alcohol or ester solvent, and g) purifying the compound of Formula-1 using an ester solvent, an alcohol solvent, or a mixture thereof, to form the compound of Formula-1.