+++Thanks hicare_1 article from Aust J CHem

[pendyala123]

Aza analogues of pteridine. VIII. 3-Amino- from 3-Alkoxy-pyrimido[5,4-e]-as-triazin- 5-ones prepared by cyclization of 3-Ethoxy-1,2,4-triazines or other means
DJ Brown and RK Lynn

Australian Journal of Chemistry, vol 27(8), pages 1781 - 1790 (year 1974)

DOI:

http://dx.doi.org/10.1071/CH9741781

[hicare]