Process for the production of the form I of the terazosin monohydrochloride anhydrous
AssigneeAlfa Chemicals Italiana S.p.A.
InventorsVincenzo Cannata, Tiziano Ferrario, Barbara Galbiati
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Abstract
The process for the production of the form I of the terazosin monohydrochloride anhydrous consists of treating at the boiling temperature terazosin monohydrochloride dihydrate with a mixture of methanol and a solvent selected from C.sub.2 -C.sub.6 straight or branched alcohols, the esters of the C.sub. -C.sub.8 carboxylic aliphatic acids with C.sub.1 -C.sub.8 straight or branched alcohols, C.sub.3 to C.sub.8 aliphatic ketones, C.sub.4 to C.sub.8 straight, branched or cyclic aliphatic ethers, aliphatic amides and the aliphatic nitriles.
Claims2
A process for the preparation of the anhydrous crystalline form I of 1-(4-amino-6,7-dimethoxy-2quinazolinyl)-4-(tetrahydro-2-furoyl)piperazine monohydrochloride which comprises the steps of:
- a) quickly adding under strong stirring (4-amino-6,7-dimethoxy-2-quinazolinyl)-4-(tetrahydro-2-furoyl)piperazine monohydrochloride dihydrate to a boiling mixture of methanol and a solvent which is a member selected from the group consisting of straight or branched C.sub.2 to C.sub.6 alcohols, esters of C.sub.1 -C.sub.8 aliphatic carboxylic acids with straight or branched C.sub.1 to C.sub.8 alcohols, C.sub.3 to C.sub.8 aliphatic ketones, C.sub.4 to C.sub.8 straight, branched or cyclic aliphatic ethers, aliphatic amides and aliphatic nitriles;
- b) heating to the boiling temperature under strong stirring for a period of time between 30 minutes and 3 hours;
- c) partially distilling off said mixture of methanol and said solvent;
- d) cooling subsequently the suspension to 20.degree. C. and filtering to separate the solid;
- e) washing the solid with the solvent and drying in an oven under vacuum at a temperature between 70.degree. C. and 75.degree. C. for a period of time between 12 and 24 hours.
Dependencies are inferred from the claim text.