| abstract |
A process for preparing 4,6-diaminopyrimido[5,4-d]pyrimidines of formula I, n n n wherein n R 1 denotes a hydrogen atom or a C 1 -C 6 alkyl group, n R 2 denotes an optionally substituted C 6 -C 10 aryl group, n R 3 denotes a hydrogen atom or a C 1 -C 6 alkyl group, and n 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. |