Connection of the Fragments How to Distinguish A and B -CH. by HMBC HHCOSY →CCo四 Choosing a Structure by HMBC How to Distinguish A and B 森疯 领流 Most Protons Were Omited for the Clearity Choosing a Skeleton by HMBC 滋如 洲2 406 Connection of the Fragments by HMBC O O O O O H H 1 H- 1 H COSY Long-range 1 H- 1 C COSY CH3 O CH3 O H3C O OH 407 OAc OAc O H HO AcO O CH3 O O OAc OAc O H HO AcO O H3C O O A B 10 9 10 9 How to Distinguish A and B 408 Choosing a Structure by HMBC Most Protons Were Omited for the Clearity OAc OAc O H HO AcO O CH3 O O OAc OAc O H HO AcO O H3C O O A B 10 9 10 9 409 OAc OAc O H HO AcO O H3C O O OAc OAc O H AcO O H3C O O HO A B 1 11 14 1 11 14 17 17 How to Distinguish A and B 410 Choosing a Skeleton by HMBC H C OAc OAc O H HO AcO O H3C O O OAc OAc O H AcO O H3C O O HO A B 1 11 14 1 11 14 17 17 411 HMBC