1 0HY Methyl (3r)-3-(7-amino-4,5-dioxo-1,4,5,6-tetrahydropyrimido[4,5-C]pyridazin-3-yl)butanoate 1.000 2 0J2 (3r)-3-(7-amino-4,5-dioxo-1,4,5,6-tetrahydropyrimido[4,5-C]pyridazin-3-yl)butanoic acid 0.857 3 Z17 (3r)-3-(7-amino-1-methyl-4,5-dioxo-1,4,5,6-tetrahydropyrimido[4,5-C]pyridazin-3-yl)butanoic acid 0.818 4 Z25 3-(7-amino-4,5-dioxo-1,4,5,6-tetrahydropyrimido[4,5-C]pyridazin-3-yl)propanoic acid 0.810 5 0J4 (2r)-2-(7-amino-4,5-dioxo-1,4,5,6-tetrahydropyrimido[4,5-C]pyridazin-3-yl)propanoic acid 0.727