| abstract |
The invention relates to a process for the preparation of 2 -methyl-4 - (4-methylpiperazin- 1-yl) - 10H- thieno- [2 , 3 -b] [1 , 5] benzodiazepine (olanzapine) of the formula (I) by reacting 4-amino-2-methyl-10H-thieno [2,3- b] [1/5] benzodiazepine hydrochloride of the formula (II) with N-methylpiperazine in an organic solvent, which comprises carrying out the reaction in the mixture of toluene and 1, 3-dimethyl-2- imidazolidinone . The invention also encompasses new 2-methyl-4- (4-methylpiperazin-l-yl) -10H-thieno [2,3- b] [1,5] benzodiazepine dihydrochloride trihydrate of the formula (IB) , the preparation thereof and pharmaceutical compositions comprising said new compound. |