InChI=1S/C16H26O4/c17-15(18)13-11-9-7-5-3-1-2-4-6-8-10-12-14-16(19)20/h3,5,7,9H,1-2,4,6,8,10-14H2,(H,17,18)(H,19,20)/b5-3-,9-7+