A specific crystalline form of zilpaterol hydrochloride, process for its preparation and intermediates used

• Main Authors: GODARD, JEAN-YVES, CHEVREMONT, YVES
• Format: Patent
• Language: English; French; German
• Published: 15.01.1997
• Edition: 6
• Subjects: CHEMISTRY; FODDER; FOODS OR FOODSTUFFS; HETEROCYCLIC COMPOUNDS; HUMAN NECESSITIES; HYGIENE; MEDICAL OR VETERINARY SCIENCE; METALLURGY; ORGANIC CHEMISTRY; PREPARATIONS FOR MEDICAL, DENTAL, OR TOILET PURPOSES; SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS ORMEDICINAL PREPARATIONS; THEIR TREATMENT, NOT COVERED BY OTHER CLASSES

Anhydrous crystalline zilpaterol hydrochloride (I), contg. less than 5% of crystals smaller than 15 mu , the rest of the crystals being smaller than 250 mu , is new. Also claimed are (I)-monohydrate and (I)-trihydrate. The claimed prepn. of (I) comprises: (i) forming a super-satd. soln. of (I) in water or in an ethanol/water mixt. at below 50 degrees C; (ii) cooling the soln. to crystallise the monohydrate; (iii) lowering the temp. to below 20 degrees C to crystallise the trihydrate; and (iv) drying to give the desired prod. A variation on the above procedure comprises dissolving (I) in water at below 30 degrees C to give a satd. aq. soln. from which the trihydrate recrystallises spontaneously. Alternatively, a soln. of (I) in a min. amt. of warm water (60-100 degrees C) is poured into a satd. soln. of (I) in a water/alcohol mixt. which has been previously stirred at below 20 degrees C and seeded with trihydrate, to give the trihydrate, which is then dried (all claimed). L'invention a pour objet le chlorhydrate de zilpatérol anhydre sous forme cristallisée, caractérisé en ce qu'il comprend moins de 5 % de cristaux d'une taille inférieure à 15 microns, le reste des cristaux ayant une taille inférieure à 250 microns. Le produit obtenu est utilisé comme additif alimentaire pour favoriser la prise de poids chez les animaux d'élevage.