compound 5-formiminotetrahydrofolate C20H24N8O6 compound CHEBI:15639 KEGG:C00664 InChI=1S/C20H24N8O6/c21-9-28-12(8-24-16-15(28)18(32)27-20(22)26-16)7-23-11-3-1-10(2-4-11)17(31)25-13(19(33)34)5-6-14(29)30/h1-4,9,12-13,21,23H,5-8H2,(H,25,31)(H,29,30)(H,33,34)(H4,22,24,26,27,32)/t12-,13-/m0/s1 UPa:UPC00664