4H-1-benzopyran-4-one, 7-hydroxy-3-(4-methoxy-3-nitrophenyl)- 7-hydroxy-3-(4-methoxy-3-nitrophenyl)-4H-chromen-4-one InChI=1/C16H11NO6/c1-22-14-5-2-9(6-13(14)17(20)21)12-8-23-15-7-10(18)3-4-11(15)16(12)19/h2-8,18H,1H