2D NMR methods

Using various chromatography methods, three merosesquiterpenes belonging to sesquiterpene quinone type, neodactyloquinone (1), dactyloquinone D (2), and dactyloquinone C (3) together with two indole derivatives indole-3- aldehyde (4) and indole-3-cacboxylic methyl ester (5) were isolated from the methanol extract of the Vietnamese marine sponge Smenospongia cerebriformis. Their structures were determined by 1D-, 2D-NMR spectra, HR-ESI-MS and in comparison with those reported in the literature.

5p giesumanh 10-11-2018 14 0   Download

Five flavonoids along with -sitosterol were isolated from the leaves of Polygonum hydropiper L. (Polygonaceae). Four flavonoids were identified as quercetin, quercetin-3-O- -L- rhamnoside (quercitrin), quercetin-3-sulphate and (+)-catechin. Their structures were established on the basis of chemical evidence and spectroscopic techniques, including 2D NMR methods.

5p uocvong04 24-09-2015 57 2   Download

By various chromatography methods, two flavonolignan silychristin (1) and isosilychristin (2) were isolated from the fruits of Silybum marianum (L.) Gaertn. cultivated in the North of Vietnam. Their structures were elucidated by analyses of the NMR (1D-, 2D-NMR) and ESI spectra. This is the first report of both 1 and 2 from S. marianum cultivated in Vietnam.

5p uocvong04 24-09-2015 46 3   Download

From the methanol extract of the leaves of Chlorophytum laxum R. Br. (Athericaceae), a new (1) and two known (2, 3) derivatives of furancarboxaldehyde, and a derivative of anthraquinone (4) were isolated by various chromatography methods. Their structures were elucidated as 5- (ethoxymethyl)-2-furancarboxaldehyde (1), 5-hydroxymethyl-2-furancarboxaldehyde (2) and cirsiumaldehyde (3) and 1,5-dihydroxy-3-hydroxymethylanthraquinone (4) by analyses of the NMR (1D-, 2D-NMR), EI-MS and ESI-MS spectra. This is the first report of 2, 3, and 4 from C. laxum.

5p uocvong04 24-09-2015 44 4   Download

By using a new own method [1], a new ethynylsteroid containing fluorine at the 17 -position: 4-chloro-pregn-4-en-3-on-16 -ol-17 -fluor-20-yne has been synthesized. Structure of the product has been determined by physical methods as IR, MS, 1 and 2D NMR.

6p uocvong03 24-09-2015 23 2   Download