Shkurko, O. P. published the artcileNMR spectra of pyrimidines. Effect of substituents on a chemical shift of amino group protons of p-substituted 2- and 5-aminopyrimidines and anilines, Product Details of C5H4N4, the publication is Khimiya Geterotsiklicheskikh Soedinenii (1979), 1683-6, database is CAplus.
NMR data for 4-substituted anilines, 5-substituted 2-aminopyrimidines, and 2-substituted 5-aminopyrimidines were subjected to correlation anal. The inductive effects were transmitted approx. equally through the benzene and pyrimidine rings. The conjugation effects were transmitted with equal efficiency through the benzene ring and from position 5 to position 2 of the pyrimidine ring; transmission from position 2 to position 5 of the pyrimidine ring was somewhat more efficient.
Khimiya Geterotsiklicheskikh Soedinenii published new progress about 56621-93-3. 56621-93-3 belongs to pyrimidines, auxiliary class Pyrimidine,Nitrile,Amine, name is 5-Aminopyrimidine-2-carbonitrile, and the molecular formula is C40H35N7O8, Product Details of C5H4N4.
Referemce:
https://pubchem.ncbi.nlm.nih.gov/compound/Pyrimidine,
Pyrimidine – Wikipedia