
2,4,5,6-Tetraaminopyrimidine sulfate is the sulfate salt of 2,4,5,6-tetraaminopyrimidine, appearing as a light yellow to ochre crystalline powder with a melting point above 300℃. It is a key intermediate in the production of methotrexate and other antifolate pharmaceuticals, and is also used as a precursor for hair dye couplers. in water. In acidic solutions, it is colorless, while in basic solutions, it turns pink to purple.