InChI=1S/C16H17NO4/c17-14(16(20)21)9-13(15(18)19)8-10-5-6-11-3-1-2-4-12(11)7-10/h1-7,13-14H,8-9,17H2,(H,18,19)(H,20,21)/t13-,14+/m0/s1