Patent ID: 7629493

Claim:
A process for the crystallisation of a compound of formula I or an acid-addition salt thereof, in which R 1 R 4 SO 2 — or A, R 2 and R 3 , independently of one another, H, Hal, alkyl having 1 to 12 C atoms, R 1 SO 2 —, Ar or Het, R 4 aryl or alkyl having 1 to 12 C atoms, Het a saturated, unsaturated or aromatic, mono- or bicyclic, heterocyclic or linear or branched organic radical containing one or more hetero atoms which is unsubstituted or mono- or polysubstituted by A, COAr, COHet and/or Hal, Ar a phenyl radical which is unsubstituted or mono- or polysubstituted by A and/or Hal, OH, OA, COOH, COOA, CONH 2 , CONA 2 , CONHA, CN, NO 2 , NH 2 , NHA, NA 2 , NHCOA, CF 3 or SO 2 A, A straight-chain or branched alkyl or hydroxyalkyl having 1 to 10 C atoms, alkenyl or alkoxyalkyl having 2 to 10 C atoms, and Hal F, Cl, Br, I comprising dissolving the respective compound of formula I, optionally with impurities, at a given dissolution temperature in water which is virtually saturated with at least one water-immiscible solvent and optionally comprises one or more water-miscible solvents, and allowing the compound of formula I to crystallise at a temperature that is lower then said dissolution temperature, and wherein the water-immiscible solvent is an alkyl alkanoate or an aromatic solvent.