- Synthesis of New Naturally Occuring 4-Phenyl-2H-1-benzopyran-2-ones
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5,7-Dimethoxy-4-(4-hydroxyphenyl)-2H-1-benzopyran-2-one and 5,7-dimethoxy-4-(4-methoxyphenyl)-2H-1-benzopyran-2-one, two new neoflavonoids occuring in Courtarea hexandra have been synthesized via Pechmann condensation.Attempts made to synthesize another 4-arylcoumarin, 5-hydroxy-7-methoxy-4-(2,5-dihydroxyphenyl)-2H-1-benzopyran-2-one, constituent of the same plant, led to the formation of the hitherto unknown 2-ethoxy-6-hydroxy-4H-1-benzopyran-4-one.
- Parmar, Virinder S.,Jain, Rajni,Singh, Suddham
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- An efficient synthesis of neoflavonoid antioxidants based on Montmorillonite K-10 catalysis
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A new approach to synthesis of neoflavonoids, based on a high yielding Montmorillonite K-10 catalyzed lactone ring forming cyclization process, is described. The utility of this methodology is exemplified by its employment in the preparation of the substituted 4-phenylneoflavonoids 1-8. The free radical scavenging properties of these substances were evaluated. The neoflavonoids 1 and 5, which mimic esculetin-type antioxidants, were observed to quench hydrazyl free radicals.
- Lee,Tseng,Lee
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p. 2247 - 2254
(2007/10/03)
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- Flavonoids Syntheses. VI. Synthesis and Spectral Properties of 4-Arylcoumarins (Neoflavones)
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Eight neoflavones were synthesized for examination of their spectral properties.In the mass spectra, 2'-oxygenated neoflavones showed characteristic fragments owing to dehydrxylation or demethoxylation.Other spectral data ultraviolet, proton and carbon-13 nuclear magnetic resonance, however, showed no specific features that could be used to characterize the structures.Keywords--neoflavone synthesis; 4-arylcoumarin; 2'-oxygenated neoflavone; mass spectrum
- Iinuma, Munekazu,Tanaka, Toshiyuki,Hamada, Koji,Mizuno, Mizuo,Asai, Fujio,et al.
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p. 3909 - 3913
(2007/10/02)
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- SYNTHESIS OF 4-ARYLCOUMARINS FROM COUTAREA HEXANDRA
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Key Word Index - Coutarea hexandra; Rubiaceae; neoflavonoids; 4-arylcoumarins; synthesis. - The structures assigned to the 5,7-dimethoxy-4-arylcoumarins isolated from Coutarea hexandra have been confirmed by synthesis, via Pechmann condensation of phlorog
- Monache, Giuliano Delle,Botta, Bruno,Monache, Franco Delle,Botta, Maurizio
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p. 1355 - 1358
(2007/10/02)
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