Study of Conformational Preferences of Erythro-Carolignan E Assessed By The Coupling Between H7'-H8' in Different NMR Solvents

Rudiyansyah Rudiyansyah (Jurusan Kimia, Fakultas MIPA, Universitas Tanjungpura, Kalimantan Barat)
Ajuk Sapar (Jurusan Kimia, Fakultas MIPA, Universitas Tanjungpura, Kalimantan Barat)
Masriani Masriani (Jurusan Kimia, Fakultas MIPA, Universitas Tanjungpura, Kalimantan Barat)

ALCHEMY Jurnal Penelitian Kimia
Vol 11, No 1 (2015): March

Erythro-carolignan E (1) has been obtained from the ethanol extract of the wood bark of Durio affinis Becc. This research was conducted in order to prove that conformational preferences of compound 1 were solvent dependent. On the basis of 1H-NMR data, the relative configuration of compound 1 was characterized by a coupling constant (3JHH) value of 3.3 Hz at H-7' in CDCl3. The coupling constant (3JHH) values of H-7' in compound 1 has changed to 4.1 Hz and 5.3 Hz in pyridine-d5 and acetonitrile-d3 respectively. As a result, the conformation of compound 1 at C7'-C8' has changed in different NMR solvents.  In conclusion, structure oferythro-carolignan E that contains a dihydroxy group at C7'-C8' is able to change in different NMR solvent.