Conformation and Dynamics of (−)‐β‐Caryophyllene

Abstract

(−)‐β‐Caryophyllene (1) adopts three conformations in solution: αα(48%), βα(28%), and ββ(24%). The conformations were identified by an analysis of the 13C‐ and 1H‐NMR spectra at −87.2 and −153.8° in connection with APT, HETCOR, and COSY spectra, and subsequent NOESY experiments. The activation parameters of the conversion αα → βα were determined from a bandshape analysis of exchange‐broadened 13C‐NMR spectra of 8‐[methylene‐13C]‐1 to give ΔH≠ = 5.9 ± 0.3 kcal/mol, ΔS = −8.1 ± 1.8 cal/mol. · K. and ΔG 298≠ = −8.3 ± 0.8 kcal/mol. The observed population ratio of the different conformers is best described by MM3.

Calculated ionization energies for a series of sesquiterpenes: comparisons with experimental vertical ionization energies and comments on related structure–activity relationships (SARs)

“…Thus, beta-caryophyllene (13), which has a mildly twisted (ca 10°) olefinic linkage [28,29] is calculated to have an IP v that is 0.2 eV lower than that of its cis-isomer isocaryophylene (18). This significant difference would not be accounted for in the SARs that have been advanced to date.…”

Isolation of a New Caryophyllane Ester fromLactarius subumbonatus: Conformational Analysis and Absolute Configuration

“…[10] In L. subumbonatus a mations, and as being almost degenerate. Contrary to these results, Fitjer et al reported a detailed low-temperature 1 H-similar behaviour is observed, given the lack of biological activity of ester 2a compared to the activities of 2b and 3a and 13 C-NMR study, [16] from which it appeared that the observed r.t. geometry was actually due to the overlap of (vide infra).…”

“…[16] The interprotonic correlations expected for the αβ conformation were equally not detect-3 J-couplings and NOE correlations, was performed. [16] The interprotonic correlations expected for the αβ conformation were equally not detect-3 J-couplings and NOE correlations, was performed.…”

5,10:13,14-Disecosteroids: novel modified steroids containing 10- and 9-membered rings

“…It is known that alkoxy radicals obtained by the oxidation of 5-and 14-hydroxysteroids such as I-III with lead tetracetate (LTA) and hypoiodite-forming reagents, readily undergo b-fragmentation of the C(5)-C (10) and C(13)-C (14) bonds to give, via C(10) and C(13) radical intermediates, the diastereoisomeric (Z)-and (E)-1(10)-unsaturated-5-oxo-5,10-secosteroids IV and V (from Ia,b), the diastereoisomeric (Z)-and (E)-1(10)-unsaturated B-nor-5,10-secosteroids XI and XII and their 10(19)-unsaturated isomer XIII (from IIIa,b), the diastereoisomeric (Z)-and (E)-12-unsaturated-14-oxo-13,14-secosteroids VI and VII and their isomeric 13(18)-unsaturated-13,14-seco-14-ketone VIII (from II), as the primary products. In addition, 12,13-epoxy-13,14-secosteroid IX and 14b,22-ether X (from II), the stereoisomeric 5, b), and 5b,19-oxetane XVI (from IIIb) are obtained. These studies have shown that the fate of the ninemembered ring C(10) radical in B-nor steroids IIIa,b 6 is considerably different from that of the corresponding 10-membered ring analog in 5-hydroxy steroids Ia,b 4 and from the nine-membered ring C(13) radical in 14a-hydroxy steroid II 4 (Scheme 1).…”