| abstract |
The invention relates to processes for the preparation of novel fused pyrimidine derivatives of the general formula (I) in which A represents a group CH 2 CH 2, CH 2 CH 2 CH 2, CH 2 CH 2 CH 2 CH 2 or CHCH; R4 is hydrogen, C1-4alkyl or optionally substituted phenyl; r is 0, 1, 2, 3 or 4; R 1 is hydrogen or C 1-5 alkanoyl; R 2 is hydrogen or C 1-5 alkanoyl or a group of general formula (a) wherein R is hydrogen, C 1-4 alkyl, C 2-4 alkenyl, phenyl or phenyl-C 1-3 alkyl; and R3 is hydrogen, which can be obtained, for example, by reacting a 2-mercapto-4,6-diamino-pyrimidine with a dihalogen derivative. The novel fused pyrimidine derivatives are used as pharmaceutical preparations for stimulating immune system function. Formula (I) |