The author of 《Synthesis of pyrimido[4,5-d]pyrimidines. An unusual rearrangement of 2-aminopyrimido[4,5-d]pyrimidin-5(6H)-one into 2-amino-4,6-dichloro-1,3,5-triazine》 were Stanovnik, B.; Koren, B.; Steblaj, M.; Tisler, M.; Zmitek, J.. And the article was published in Vestnik Slovenskega Kemijskega Drustva in 1982. Electric Literature of C7H10N4O2 The author mentioned the following in the article:
Pyrimidopyrimidine I (R = NH2, R1 = H) was obtained by treating 5-carbamoyl-2,4-pyrimidinediamine (II) with HC(OEt)3 or CH(NHCHO)3. I (R = N:CMeOEt, R1 = Me) was obtained from II and MeC(OEt)3. Treatment of I (R = NH2, R1 = H) with POCl3 gave the triazine III. In the experiment, the researchers used Ethyl 2,4-diaminopyrimidine-5-carboxylate(cas: 15400-54-1Electric Literature of C7H10N4O2)
Ethyl 2,4-diaminopyrimidine-5-carboxylate(cas: 15400-54-1) belongs to anime. Acylation is one of the most important reactions of primary and secondary amines; a hydrogen atom is replaced by an acyl group (a group derived from an acid, such as RCOOH or RSO3H, by removal of ―OH, such as RC(=O)―, RS(O)2―, and so on). Reagents may be acid chlorides (RCOC1, RSO2C1), anhydrides ((RCO)2O), or even esters (RCOOR′); the products are amides of the corresponding acids.Electric Literature of C7H10N4O2
Referemce:
Pyrimidine | C4H4N2 – PubChem,
Pyrimidine – Wikipedia