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Constituents of the acidic part of commercial Brazilian lantana oil
Author(s) -
Weyerstahl Peter,
Marschall Helga,
Christiansen Christian
Publication year - 2001
Publication title -
flavour and fragrance journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.393
H-Index - 70
eISSN - 1099-1026
pISSN - 0882-5734
DOI - 10.1002/1099-1026(200101/02)16:1<50::aid-ffj945>3.0.co;2-1
Subject(s) - chemistry , trimethylsilyl , yield (engineering) , organic chemistry , silane , medicinal chemistry , stereochemistry , metallurgy , materials science
The acidic part of Brazilian lantana oil contains mainly new bisabolene and tricyclic helifolene derivatives. 3‐Formyl‐helifolen‐12‐oic acids 14, 16 , 11‐formyl‐helifolen‐15‐oic acids 10, 12 , 6,10‐epoxybisabol‐2‐ 18, 20, 22, 24 , and ‐3‐en‐12‐oic acids 19, 21, 23, 25 , γ‐( 26 ) and ar ‐curcumen‐15‐oic acids ( 27 ), as well as the known ar ‐curcumen‐12‐oic acid ( 28 ) and amorpha‐4,9,11‐trien‐12‐oic acid, were characterized as their methyl esters. The bifunctionalized methyl helifolenoates 10, 12, 14, 16 were reduced with NaBH 4 to the corresponding hydroxy esters 11, 13, 15, 17 . Their configuration was clarified by NOED spectra. The helifolen‐12‐ ( 1a–4a ) and ‐15‐oic acids ( 5a ) are present in the acidic part only as traces. Their spectral data were obtained by isolation from an autoxidized fraction of the known aldehydes. 1 The parent helifolane ( syn . khusiane or allo ‐cedrane) skeleton 8/9 was prepared by stepwise reduction of esters 1b–4b with LiAlH 4 and H 2 /Pd/C to yield the helifolanols 6 and 7 . Treatment of 6, 7 with O‐ p ‐tolylchlorothionoformate gave the corresponding thionocarbonates which were reduced with tris(trimethylsilyl)silane to afford helifolanes 8 and 9 . Copyright © 2001 John Wiley & Sons, Ltd.