可提供原料（原分子结构）。下面4个化合物，各需100mg。

2-Amino-3,4-dihydroxy-2-hydroxymethyl-9-methyl-14-oxo-icosa-6,8-dienoic acid

C22H39NO6
Exact Mass: 413.28
Mol. Wt.: 413.55
m/e: 413.28 (100.0%), 414.28 (25.3%), 415.28 (4.2%)
C, 63.89; H, 9.51; N, 3.39; O, 23.21