2,4-Diamino-6-(hydroxymethyl)pyrido[2,3-d]pyrimidine

(S)-2-({4-[(2,4-Diamino-pyrido[2,3-d]pyrimidin-6-ylmethyl)-amino]-naphthalene-1-carbonyl}-amino)-pentanedioic acid diethyl ester

N'-(2-Amino-6-bromomethyl-pyrido[2,3-d]pyrimidin-4-yl)-N,N-dimethyl-formamidine

diethyl N-<4-<<(2,4-diaminopyrido<2,3-d>pyrimidin-6-yl)methyl>methylamino>naphthoyl>-L-glutamate

diethyl 2-[[4-[(2,4-diaminopyrido[2,3-d]pyrimidin-6-yl)methylamino]benzoyl]amino]pentanedioate

diethyl (4-(((2,4-bis((triphenyl-l5-phosphaneylidene)amino)pyrido[2,3-d]pyrimidin-6-yl)methyl)(methyl)amino)-1-naphthoyl)-L-glutamate

2-Amino-6-(bromomethyl)-3,4-dihydro-4-oxopyrido<2,3-d>pyrimidine

6-(Bromomethyl)-1,2,3,4-tetrahydro-2,4-dioxopyrido<2,3-d>pyrimidine

2-Desamino-2-oxo-10-thia-5-deazafolic acid

10-Thia-5-deazapteroic acid

10-Thia-5-deazafolic acid

Ethyl 10-thia-5-deazapteroate

Di-tert-butyl 2-desamino-2-oxo-10-thia-5-deazafolate

Di-tert-butyl 10-thia-5-deazafolate