Barlin, G. B. published the artcileIonization constants of heterocyclic substances. IX. Protonation of aminopyridines and aminopyrimidinones, HPLC of Formula: 33631-04-8, the publication is Journal of the Chemical Society [Section] B: Physical Organic (1971), 1425-32, database is CAplus.
Ionization constants and uv spectra are reported for amino-2-hydroxypyridines (amino-2-pyridones), amino-4-hydroxypyridines(amino-4-pyridones), and amino-2,4-di-hydroxypryimidines (amino-2,4-pyrimidinediones) and their O-and ring N-Me derivatives Protonation of 3- and 5-amino-2-hydroxypyridines and 3,4-diamino-2-hydroxypyridine (I) occurs first at the amino group (the 3-NH2 of I), but 4- and 6-amino-2-hydroxypyridines and 2- and 3-amino-4-hydroxypyridines are protonated first at O. The most basic center of 4,5-diamino-2,6-dihydroxypyrimidine is the 5-NH2 group.
Journal of the Chemical Society [Section] B: Physical Organic published new progress about 33631-04-8. 33631-04-8 belongs to pyridine-derivatives, auxiliary class Pyridine,Amine,Ether, name is 2-Methoxypyridine-3,4-diamine, and the molecular formula is C6H9N3O, HPLC of Formula: 33631-04-8.
Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem