Preparation de 9-hydroxy-3-(2-hydroxyethyl)-2-methyl-4h-pyrido`1,2-a!pyrimidin-4-one et leurs cristaux

La presente invention concerne un procede de preparation d'une 3-(2-chloro-ethyl)-9-hydroxy-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one cristalline sensiblement exempte de 2-acetylbutyrolactone.