151890-75-4 3',6'-Dihydroxy-3-oxo-spiro(isobenzofuran-1(3H),9'-9H-xanthene)-6-carboxylic acid 2-((phosphonothio)acetyl)hydrazide Doixc-pth Spiro(isobenzofuran-1(3H),9'-(9H)xanthene)-6-carboxylic acid, 3',6'-dihydroxy-3-oxo-, 2-((phosphonothio)acetyl)hydrazide