Patent ID: 6849734

Claim:
A 2-Chloro-4,6-diamino-7,8-dihydropyrimido[5,4d]-pyrimidine of the formula II wherein R 1 denotes a hydrogen atom or a C 1 -C 6 alkyl group, R 2 denotes an optionally substituted C 6 -C 10 aryl group, R 3 denotes a hydrogen atom or a C 1 -C 6 alkyl group, and R 4 denotes a hydrogen atom or an optionally substituted C 1 -C 6 alkyl, C 3 -C 6 alkenyl, C 3 -C 8 cycloalkyl or a 4- to 7-membered, nitrogen-containing heterocyclyl group, or R 3 and R 4 together with the nitrogen atom linked to them denote an optionally substituted heterocyclyl group, and PG 1 denotes a C 1-6 alkanoyl group.