Process for the synthesis of ivabradine and addition salts thereof with a pharmaceutically acceptable acid

A process for the synthesis of ivabradine of formula (I):

• wherein a compound of formula (VI):
• wherein R1 and R2, which are the same or different, represent linear or branched (C1-C6)alkoxy groups or together with the carbon atom carrying them form a 1,3-dioxane, 1,3-dioxolane or 1,3-dioxepane ring,
• is subjected to a reductive amination reaction with a compound of formula (VII):
• in the presence of a reducing agent,
• in an organic solvent, a mixture of organic solvents or a mixture of organic solvent(s) and water,
• to yield a compound of formula (VIII):
• wherein R1 and R2 are as defined hereinbefore,
• which is subjected to a condensation reaction with a compound of formula (IX):
• in the presence of a base in an organic solvent,
• to yield a compound of formula (X):
• wherein R1 and R2 are as defined hereinbefore,
• which is subjected to a cyclisation reaction in an acid medium to yield a compound of formula (V):
• which is subjected to a hydrogenation reaction to yield ivabradine of formula (I), which may optionally be converted into addition salts thereof with a pharmaceutically acceptable acid selected from hydrochloric acid, hydrobromic acid, sulphuric acid, phosphoric acid, acetic acid, trifluoroacetic acid, lactic acid, pyruvic acid, malonic acid, succinic acid, glutaric acid, fumaric acid, tartaric acid, maleic acid, citric acid, ascorbic acid, oxalic acid, methanesulphonic acid, benzenesulphonic acid and camphoric acid, and into hydrates thereof.