The paper reviewed the 13 CNMR features of natural taxane diterpenoids according to their carbonskeleton types. In the 13 CNMR it is easy to distinguish the 6/8/6 and 5/7/6 membered rings by observation of the 13 CNMR...The paper reviewed the 13 CNMR features of natural taxane diterpenoids according to their carbonskeleton types. In the 13 CNMR it is easy to distinguish the 6/8/6 and 5/7/6 membered rings by observation of the 13 CNMR data of C1 and C15. The remarkable differences of the resonance of C13 and C12 were found. In addition, based on various chemical environments many obscured chemical shifts of carbons can be distinguished, such as the oxygenated tertiary carbons of C2, C5, C7, C9 and C13, and sometimes between C9 and C10, as well as between aliphatic quaternary carbons of C8 and C15, and secondary carbons of C6 and C14. All the abovementioned characteristics are helpful for structural elucidation and assignments of the carbon signals of taxoids.展开更多
文摘The paper reviewed the 13 CNMR features of natural taxane diterpenoids according to their carbonskeleton types. In the 13 CNMR it is easy to distinguish the 6/8/6 and 5/7/6 membered rings by observation of the 13 CNMR data of C1 and C15. The remarkable differences of the resonance of C13 and C12 were found. In addition, based on various chemical environments many obscured chemical shifts of carbons can be distinguished, such as the oxygenated tertiary carbons of C2, C5, C7, C9 and C13, and sometimes between C9 and C10, as well as between aliphatic quaternary carbons of C8 and C15, and secondary carbons of C6 and C14. All the abovementioned characteristics are helpful for structural elucidation and assignments of the carbon signals of taxoids.
