Patent ID: 7232911

Claim:
Process for the preparation of a 2-aminomethylpyridine derivative of general formula (I) or a salt thereof: in which: n represents 0, 1, 2 or 3, X is halogen atom, Y may be the same or different and may be a halogen atom, a halogenoalkyl, a alkoxycarbonyl or a alkylsulphonyl; said process comprising: (A)—a first step according to reaction scheme 1: in which benzophenone (BP) is reacted with glycine alkyl ester hydrochloride (GAE.HCl) at reflux in a non polar solvent, said solvent being capable of forming an azeotrope with water, in the presence of an acid catalyst and a trialkylamine base, in a BP/GAE.HCl molar ratio of from 1 to 4, to provide a benzophenone glycine imine derivative (BPGI); (B)—a second step according to reaction scheme 2; in which: X, Y and n are as defined above, z is a leaving group, comprising the reaction of the benzophenone glycine imine derivative (BPGI) solution obtained in step one with a pyridine derivative (Py-z) in the presence of a dry inorganic base, in the presence of a catalyst and an aprotic polar solvent, the mixture being heated at reflux, to provide a pyridine glycine imine derivative (PyGI); (C)—a third step according to reaction scheme 3; in which X, Y and n are as defined above comprising the addition to the previous pyridine glycine imine derivative (PyGI) solution of an aqueous hydrochloric acid at up to 25° C., in a HCl/PyGI molar ratio of at least 1, to provide a pyridine glycine ester hydrochloride derivative (PyGE.HCl); (D)—a fourth step comprising the conversion of the pyridine glycine ester hydrochloride derivative (PyGE.HCl) into a compound of general formula (I) by heating under reflux of water.