2H,8H-Benzo[1,2-b:5,4-b']dipyran-2-one,5-[(9,10-dihydro-9-hydroxy-8,8-dimethyl-2-oxo-2H,8H-benzo[1,2-b:3,4-b']dipyran-10-yl)oxy]-8,8-dimethyl-,cis-(+)-