<unk>  (or<unk>  ribotide) is an intermediate in the formation of purines.
5'-phosphoribosyl-5-aminoimidazole
Dihydrouracil
Tetrahydrofolic acid
5'-Guanidinonaltrindole
4-Aminobenzoic acid
Thioguanine
8-Hyydroxyquinoline
Primaquine phosphate