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NMR assignments and absolute stereochemistry of two guaianolide sesquiterpenes from Tanacetum densume subsp. amani
Author(s) -
Ulubelen Ayhan,
Gören Nezhun,
Jiang TianYi,
Scott Lincoln,
TianasoaRamomojy Manoelson,
Snyder John M. K.
Publication year - 1995
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1260331111
Subject(s) - chemistry , sesquiterpene , asteraceae , stereochemistry , absolute (philosophy) , absolute configuration , ketone , germacranolide , sesquiterpene lactone , botany , organic chemistry , biology , philosophy , epistemology
The guaianolide sesquiterpene pyrethroidinin (1) and the corresponding ketone parishin A (2) wee isolated from Tanacetum densum subsp. amani (Asteraceae). The absolute stereochemistry of 1 was established as (1 R , 3 R , 6 S , 7 S , 10 R ) on the basis of the differential shielfing in the 1 H NMR spectra of the (−)‐ and (+)‐ O ‐methylmandelate esters. The structure, including absolute stereochemistry, of 2 was confirmed by oxidation of 1 whit Jones' reagent.