| abstract |
The present invention relates to a process for the preparation of methyl- {4,6-diamino-2- [1- (2-fluorobenzyl) -1H-pyrazolo [3,4- b] pyridino- Pyrimidino-5-yl} methylcarbamates and for the purification of crude products of compounds of formula (I) for use as pharmaceutical active substances. For purification, methyl- {4,6-diamino-2- [1- (2-fluorobenzyl) -1H-pyrazolo [3,4- b] pyridino- -Yl} methylcarbamate-sulphonyldimethan (1: 1), i.e. a compound of formula (II) below, is isolated as an intermediate present in the mixture optionally in the purification process or is produced as an intermediate. ≪ Formula (I) > ≪ Formula (II) > |