Validation of Structures of Novel Eudesmane Sesquiterpenes Using Scatter Plots

Aim: This study explores the potential of scatter plots as a tool in validating proposed structures for novel Eudesmane Sesquiterpenes.
Methodology: Substituents on the skeletons of several Eudesmane compounds were coded and plotted against the 13C chemical shift values for each Carbon position on the skeleton (C1-C15).
Results: The range of chemical shift values (for each Carbon position) over which each substituent type may be obtained was determined from the scatter plots. The results imply that when the carbon atom C1 on a novel eudesmane compound is assigned any chemical shift value between 26.1 and 54.0, then that position should definitely be without a substituent. Chemical shift values between 68.1 and 91.3 (on C1) would indicate that β-OH as the most likely substituent (with 23.29% probability) while values within the 121.7 – 160.4 range indicate with 100% certainty that the substituent is ∆1. Similar conclusions can be drawn for all the chemical shift ranges for the different carbon positions.
Conclusion: These chemical shift ranges could be useful in validating proposed structures for novel Eudesmane sesquiterpenes.