A Sesquiterpene diketone from Lippia integrifolia

Sesquiterpenes from Lippia integrifolia Essential Oil

“…The essential oil was fractionated by preparative gas chromatography (GC) using a nonpolar column (SE-30). The known sesquiterpenes 5-africanene (1), (E)-β-caryophyllene, R-humulene, lippifoli-1(6)-en-5-one, 2 davanone; 10 the compounds 2-4 based on the rare africanane skeleton; and compound 5, with an asteriscane skeleton, were obtained. The fractions were analyzed by capillary GC on columns with heptakis(6-Otert-butyldimethylsilyl-2,3-di-O-methyl)-β-cyclodextrin (6-TBDMS-2,3-Me-β-CD) and heptakis (2,6- 9 However, the main peak of the sesquiterpene hydrocarbon fraction was a mixture (60:40%) of the two components 2 and 3, both having identical retention times on columns with a nonpolar dimethylpolysiloxane phase (CpSil 5).…”

“…Catala `n et al reported the isolation of 3R-hydroxy-6-asteriscene from L. integrifolia 6 with a cis configuration of H-2 and H-9 (based on the large coupling constant of 11.0 Hz), as is the case in asteriscanolide, which has been studied by X-ray diffraction. 13 The coupling constant of 10.7 Hz between H-2 and H-9 observed in 5 (see the 1…”

“…Hieron is used as a remedy for stomach disorders and as a sedative. In previous reports, the essential oil of L. integrifolia was found to be rich in constituents based on the rare africanane skeleton. − A reinvestigation of the steam distillation products resulted in the identification of three africanane-type sesquiterpene hydrocarbons: the known compound 1 , previously extracted from the liverwort Pellia epiphylla (L.) Corda; two new hydrocarbons ( 2 and 3 ); a new africanane alcohol ( 4 ); and a new asteriscadiene ( 5 ). The isolation and charactarization of these compounds are the subject of the present communication.…”

Trace Constituents of Lippia integrifolia

“…The C-3 epimer of 2, obtained as an intermediate of a biomimetic sequence for the transformation of humulene into 7-protoilludyl cation derivatives (15), turned out to be helpful in establishing the stereochemistry of 2 at C-3. Thus, molecular modelling calculations (6,7,16) of 2 and its C-3 epimer, together with the analysis of the vicinal coupling constants of 2 by means of a Karplus-type equation (17,18), revealed that the eight-membered rings of both substances adopt a conformation close to a chair Cs (19)• The methyl group at C-3 in 2 remains pseudoaxial, while in the C-3 epimer, it remains pseudo-equatorial. Thes results are consistent with the observed chemical shifts of these methyl groups as measured in CC14 (2, 1.06 ppm vs. its C-3 epimer, 1.15 ppm), and therefore with the stereochemistry at C-3 for both substances.…”