2,3-Dihydroxy-6-hydroxypyridazin-3-one butoxycarboxylate 2971-27-9 3(2H)-Pyridazinone, 6-hydroxy-, butoxycarboxylate 4-25-00-00025 (Beilstein Handbook Reference) BRN 0198377 n-Butyl 2,3-dihydro-3-oxo-6-pyridazinyl carbonate