Process for obtaining quinapryl hydrochloride and solvates useful for isolating and purifying quinapryl hydrochloride

A process for obtaining quinapril hydrochloride of formula (1)

• which comprises the stages of:
• a) treatment of the benzyl ester of quinapril (II)
• where Bz is the benzyl radical, with alcohol and hydrochloric acid or hydrogen chloride and hydrogenation of same through the addition of an appropriate hydrogenation catalyst;
• b) removal of the solvent used in step a);
• c) addition of toluene to precipitate the quinapril hydrochloride as a toluene solvate;
• d) treatment of the toluene solvate of quinapril hydrochloride with a solvent belonging to class 3, capable of forming a solvate of quinapril hydrochloride from which it is possible to eliminate said solvent by drying in an oven without degrading the quinapril hydrochloride;
• and
• e) drying of the solvate obtained in step d) at a temperature between 40° C. and 50° C. to yield quinapril hydrochloride (I).