InChI=1S/C16H24O4/c17-15(18)13-11-9-7-5-3-1-2-4-6-8-10-12-14-16(19)20/h1-2,5-8H,3-4,9-14H2,(H,17,18)(H,19,20)/b2-1+,7-5+,8-6+