InChI=1S/C18H18N2O/c19-11-12-5-8-18(17-4-2-1-3-16(12)17)20-13-6-7-14(20)10-15(21)9-13/h1-5,8,13-15,21H,6-7,9-10H2/t13-,14+,15+