Abstract
A biomimetic transformation of p-menthene glucosides into aromatic monoterpenoids that alluded to mechanisms for essential oil metabolism, which lines up with the precepts of molecular economy, is described. Acid treatment of (-)-(3 S,4 S,6 R)-3,6-dihydroxy-1-menthene 3- O-β-d-glucopyranoside (1) and (-)-(3 S,4 R,5 R,6 S)-3,5,6-trihydroxy-1-menthene 3- O-β-d-glucopyranoside (2), from Ageratina glabrata, yielded p-cymene (7) and carvacrol (9). The stable oxidized intermediates (+)-(3 S,4 S,6 R)-3,6-dihydroxy-1-menthene (3), (+)-(1 S,4 S,6 R)-1,6-dihydroxy-2-menthene (4), (+)-(1 R,4 S,6 R)-1,6-dihydroxy-2-menthene (5), (+)-(4 S,6 R)-yabunikkeol (6), (+)-(4 S)-carvotanacetone (8), (+)-(1 S,4 S,5 R,6 R)-1,5,6-trihydroxy-2-menthene (15), (+)-(1 R,4 S,5 R,6 R)-1,5,6-trihydroxy-2-menthene (16), and the new (+)-(4 S,5 R,6 S)-1(7),2-menthadiene (17) permitted establishment of the reaction mechanisms. The reactivity of the hydroxy groups of 4 and 5, as well as those of 15 and 16, was compared by acetylation reactions and supported by DFT calculations, revealing diminished reactivity in 4 and 15 due to the cis configuration of their hydroxy groups at C-1 and C-6. In addition, p-cymene (7) was detected as one of the major constituents of the essential oil of A. glabrata, which matches well with the biomimetic study.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.