- One-pot synthesis of 4 h -chromenes by tandem benzylation and cyclization in the presence of sodium bisulfate on silica gel
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A simple and efficient method has been developed for the synthesis of 4H-chromenes from o-hydroxybenzylic alcohols and dicarbonyl compounds containing active methylene groups by using silica gel supported sodium bisulfate. Various dicarbonyl compounds suc
- Aoyama, Tadashi,Yamamoto, Takumi,Miyota, Saki,Hayakawa, Mamiko,Takido, Toshio,Kodomari, Mitsuo
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supporting information
p. 1571 - 1576
(2014/07/08)
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- Trimethylchromens
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Thermal decomposition of 4-(4-hydroxyphenyl)-2,2,4-trimethylchromane (1) gives 2,2,4-trimelhyl-2H-chromen (2) and 2,2-dimethyl-4-methylenechroman (3). Under influence of hydrochloric acid, 3 isomerizes smoothly to 2. Under similar reaction conditions 2′-hydroxy-2,4,4-trimethylflavan (4) is transformed into 2 and 2,4,4-trimethyl-4H-chromen (5); elimination of the phenol moiety is accompanied with a rearrangement. Opening of the pyran ring with subsequent re-cyclization seems to be more reliable expia nation of this transformation than simple 1-3 migration of the methyl group.
- Nowakowska,Daszkiewicz,Kyziol
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p. 1542 - 1549
(2007/10/03)
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- REACTION OF PHENOL WITH ACETONE IN THE PRESENCE OF ALUMINUM PHENOLATE
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The condensation of phenol with acetone in the presence of aluminum phenolate leads to a mixture of isomeric bis(hydroxyphenyl)propanes and 2'- and 4'-hydroxy-2,4,4-trimethylflavans, in which 2-(2-hydroxyphenyl)-2-(4-hydroxyphenyl)propane usually predominates.
- Kozlikovskii, Ya. B.,Chernyaev, B. V.
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p. 512 - 514
(2007/10/02)
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