Process for preparing pitolisant hydrochloride and solid-state forms thereof

A process for preparing pitolisant or a pharmaceutically acceptable salt and its solid state forms thereof, comprising:

• a) providing 3-(4-chlorophenyl)-propionic acid of Formula-(IV);
• b) converting 3-(4-chlorophenyl)-propionic acid of Formula-(IV) to its acid chloride of Formula-(VI) or acid anhydride of Formula-(VIA);
• c) reducing acid chloride of Formula-(VI) or acid anhydride Formula-(VIA), where R is an alkyl or a phenyl, to obtain 3-(4-chlorophenyl)-propanol of Formula-(V);
• d) treating compound of formula (V) with activating group to obtain a compound of formula (III);
• e) reacting 3-(piperidin-1-yl)propan-1-ol
• with Formula-(III);
• in the presence of a solvent and a base to obtain pitolisant;
• wherein the AG is an activating group;
• f) optionally treating pitolisant with an acid to form pitolisant first salt;
• and
• g) converting pitolisant or pitolisant first salt to pharmaceutically acceptable salt or solid state forms of pitolisant;
• with the proviso that the base in step e) is not sodium hydride;
• and
• wherein AG is selected from a methyl sulfonate, an ethylsulfonate, a phenylsulfonate, a tolylsulfonate, a p-nitrophenyl sulfonate, a benzyl sulfonate, a trifluoromethylacyl ester, a trichloromethylacyl ester, a phenylacyl ester, a p-nitro-phenylacyl ester, and a p-chloro-phenylacyl ester.