O-Alkylation of Menthone Oxime: Synthesis and ¹³C NMR Studies of a Series of Novel Oxime Ethers

Abstract

A series of novel menthone oxime ethers were synthesized in three steps starting from (–)-menthol. Analysis of the ¹³C NMR chemical shift differences between α carbons of oxime derivatives (O-alkyl oximes) provides a convenient and reliable means of assigning oxime stereochemistry. It has been found that carbons syn to the oxime are shifted more upfield than carbons anti to the oxime moiety. Significant E products were obtained.

Keywords:

• ¹³C NMR
• chemical shifts
• menthone oxime ethers
• oxime configuration

ACKNOWLEDGMENT

The authors are thankful for the financial support from the H. E. J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences. Two of us, S. F. and H. S., wish to thank the Umaer Basha Foundation for generous financial support.

Notes

Note. Solvent: CDCl₃.