InChI=1S/C14H17BrN2O4/c1-20-10-5-4-9(15)13(21-2)12(10)14(19)16-7-8-3-6-11(18)17-8/h4-5,8H,3,6-7H2,1-2H3,(H,16,19)(H,17,18)/t8-/m0/s1