Definition: A family of 6-membered heterocyclic compounds occurring in nature in a wide variety of forms. They include several nucleic acid constituents (CYTOSINE; THYMINE; and URACIL) and form the basic structure of the barbiturates.
piritrexim [ BW 301U,2,4-diamino-6-(2,5-dimethoxybenzyl)-5-methylpyrido(2,3-d)pyrimidine,BW-301U,BW301U,piritrexim monohydrochloride ] RN given refers to parent cpd; structure given in first source
