Improved synthesis of methyl- and phenyl-substituted pyrido[2,3-d]pyrimidine-2,4-diamines

Article abstract of DOI:10.1002/ardp.19943270406

The title compounds 4b-g, 10a,b and 13 can be prepared in improved yields by 'cyclocondensation' of the 1,3-biselectrophiles 1a-e, 5b,f,g, 7b,d, 8a,b, and 12 with 2,4,6-triaminopyrimidine (2).