Abstract: N-[4-{1-Hydroxy-3-(2-amino-4-hydroxy-5,6,7,8-tetrahydropyrido[2,3-d]pyrimid in-6-yl)prop-2-yl )benzoyl]-glutamic acid, it salts, and derivatives thereof, have an inhibitory effect on one or more enzymes which utilize folic acid and can be used, alone or in combination, to inhibit the growth of those neoplasms which otherwise depend upon the enzymes so inhibited. The compounds can be prepared through catalytic hydrogenation of a protected derivative of N-[4-{1-hydroxy-3-(2-amino-4-hydroxy-pyrido[2,3-d]pyrimidin-6-yl)prop-2-en -2-yl)benzoyl]glutamic acid and removal of the protecting groups.