1,3-Bis(2-carboxychromone-7-oxy)-2-hydroxypropane 16139-47-2 37092-38-9 4H-1-Benzopyran-2-carboxylic acid, 7,7'-((2-hydroxy-1,3-propanediyl)bis(oxy))bis(4-oxo- 81882-24-8 Disodium cromproxate