10.1021/np060204e.s006
Bonnie Rasmussen
Bonnie
Rasmussen
Aimee-Justine Nkurunziza
Aimee-Justine
Nkurunziza
Matthias Witt
Matthias
Witt
Hellen A. Oketch-Rabah
Hellen A.
Oketch-Rabah
Jerzy W. Jaroszewski
Jerzy W.
Jaroszewski
Dovyalicin-Type Spermidine Alkaloids from <i>Dovyalis</i> Species
American Chemical Society
2006
348 K
NMR experiments
Dovyalis abyssinica
dovyalicin
ambient temperature
activation parameters
amide bond
trans conformers
Dovyalis SpeciesPhytochemical investigations
kJ
phenol glucoside
chiroptical methods
2006-09-22 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Dovyalicin_Type_Spermidine_Alkaloids_from_i_Dovyalis_i_Species/3057967
Phytochemical investigations of <i>Dovyalis abyssinica</i>, <i>D. hebecarpa</i>, and <i>D. macrocalyx</i> revealed two new spermidine-type alkaloids, dovyalicin E (<b>3</b>) and dovyalicin F (<b>4</b>), along with the previously described dovyalicin A (<b>1</b>), dovyalicin
B (<b>2</b>), and dovyalicin C (<b>5</b>). In addition, a new phenol glucoside, 4-hydroxytremulacin (<b>7</b>), and the new 1,2-cyclohexanediol
glucoside <b>9</b>, as well as the known compounds methyl 1-hydroxy-6-oxocyclohex-2-enecarboxylate (<b>6</b>) and tremulacin
(<b>8</b>), were isolated. The structures were established using homo- and heteronuclear two-dimensional NMR experiments
and chiroptical methods. At ambient temperature, the <i>N</i>-disubstituted amide <b>4</b> exists as a mixture of <i>cis</i> and <i>trans</i>
conformers. Variable-temperature <sup>1</sup>H NMR studies showed that time-averaged spectra are obtainable at 348 K, and the
activation parameters determined for the rotation about the amide bond were Δ<i>H</i><sup>⧧</sup> = 89 ± 4.6 kJ/mol, Δ<i>S</i><sup>⧧</sup> = 65 ± 14
kJ/mol·K, and Δ<i>G</i><sup>⧧</sup>(298K) = 70 ± 4.5 kJ/mol.