The present invention relates to a process for preparing 4,6-diaminopyrimido[5,4-d]pyrimidines of formula I,
wherein R1 to R4 have the meanings given in claim 1, as well as new intermediate products which are involved in this process.
本发明涉及一种制备式I中R1到R4具有权利要求书中所述含义的4,6-二
氨基嘧啶并[5,4-d]
嘧啶的过程,以及参与该过程的新中间体产物。