- NEW COUMARINS OF Haplophyllum obtusifolium
-
Two coumarins have been isolated from an ethanolic extract of the epigeal part of Haplophyllum obtusifolium Lebed.: capensin (I) and the new coumarin obtusicin, C5H16O6, (II), mp 81-91 deg C (CH3OH).The acid hydrolysis of (I) and (II) leads to fraxetin.On the basis of the results of a study of acetylation products and the spectral characteristics (IR, UV, PMR, and mass spectra) it has been established that obtusician has the structure of 8-hydroxy-7-(4'-hydroxy-3'-methyl-but-2'-enyloxy)-6-methoxycoumarin.
- Batirov, E. Kh.,Matkarimov, A. D.,Malikov, V. M.,Yagudaev, M. R.,Seitmuratov, E.
-
-
Read Online
- Gastroprotective efficacy and safety evaluation of scoparone derivatives on experimentally induced gastric lesions in rodents
-
This study investigated the gastroprotective efficacy of synthesized scoparone derivatives on experimentally induced gastritis and their toxicological safety. Six scoparone derivatives were synthesized and screened for gastroprotective activities against HCl/ethanol- and indomethacin-induced gastric ulcers in rats. Among these compounds, 5,6,7-trimethoxycoumarin and 6,7,8-trimethoxycoumarin were found to have gastroprotective activity greater than the standard drug rebamipide; 6-methoxy-7,8-methylenedioxycoumarin, 6-methoxy-7,8-(1-methoxy)-methylenedioxycoumarin, 6,7-methylenedioxycoumarin, and 6,7-(1-methoxy)-methylenedioxycoumarin were found to be equipotent or less potent that of rebamipide. Pharmacological studies suggest that the presence of a methoxy group at position C-5 or C-8 of the scoparone’s phenyl ring significantly improves gastroprotective activity, whereas the presence of a dioxolane ring at C-6, C-7, or C-8 was found to have decreased activity. In order to assess toxicological safety, two of the potent gastroprotective scoparone derivatives-5,6,7-trimethoxycoumarin and 6,7,8-trimethoxycoumarin-were examined for their acute toxicity in mice as well as their effect on cytochrome P450 (CYP) enzyme activity. These two compounds showed low acute oral toxicity in adult male and female mice, and caused minimal changes to CYP3A4 and CYP2C9 enzyme activity. These results indicate that compared to other scoparone derivatives, 5,6,7-trimethoxycoumarin and 6,7,8-trimethoxycoumarin can improve gastroprotective effects, and they have low toxicity and minimal effects on drug-metabolizing enzymes.
- Son, Dong Ju,Lee, Gyung Rak,Oh, Sungil,Lee, Sung Eun,Choi, Won Sik
-
-
Read Online
- A simple, high-yielding method for the methylenation of catechols
-
The methylenation of a variety of catechols is described, employing cesium carbonate and bromochloromethane in dimethylformamide at 110°C or acetonitrile at reflux. The corresponding methylenedioxy derivatives are obtained in 86-97 yield. Utilization of this method provided β-hydrastine in 70% yield from its corresponding dihydroxy analog.
- Zelle,McClellan
-
p. 2461 - 2464
(2007/10/02)
-
- A High-Yield Method for the Methylenation of o-Dihydroxyaromatic Compounds: Synthesis of Methylenedioxycoumarins
-
Reaction of o-dihydroxycoumarins and catechols with sodium hydride in hexamethylphosphoric triamide and dihalomethane provides the corresponding methylenedioxy compounds under mild conditions and in excellent yields.
- Castillo, P.,Rodriguez-Ubis, J. C.,Rodriguez, F.
-
p. 839 - 840
(2007/10/02)
-