Patent ID: 7745664

Claim:
Process for preparing an acid addition salt of venlafaxine which comprises: (a) converting a venlafaxine precursor selected from the group consisting of N,N-didesmethyl venlafaxine of formula (I), a salt thereof, spiro venlafaxine of formula (II), and a salt thereof to venlafaxine in an aqueous solution, wherein the conversion is carried out in the presence of a salt of formic acid which is selected from the group consisting of a metal salt and an ammonium salt of formic acid, and wherein the molar ratio of the salt of formic acid to the venlafaxine precursor is 0.3-10 to 1, (b) extracting venlafaxine from the aqueous solution with a water-immiscible organic solvent to obtain an organic venlafaxine solution; and (c) reacting the organic venlafaxine solution with an acid to prepare the acid addition salt of venlafaxine.