- Application of Oxidative Aryl Migration in Organo-selenium and -tellurium Compounds to the Synthesis of 2-Arylpropanoic Acids
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The ethylene acetals of aryl α-phenylseleno- and α-phenyltelluro-ethyl ketones i, Ph, Br) and 5-bromo-6-methoxy-2-naphthyl> have been prepared in 12-83percent yields by treating the corresponding α-bromo compounds with diphenyl diselenide-sodium or diphenyl ditelluride-sodium, respectively, in tetrahydrofuran-dimethylformamide under reflux for 6-10 h, during which the bromine is substituted by the PhSe or PhTe group.This substitution is not observed when the (PhM)2-NaBH4-EtOH (M=Se, Te) system which is known as a source of PhM- anion is used.Oxidation of the acetals thus formed with an excess of meta-chloroperbenzoic acid at 20-25 deg C for 1 h affords hydroxy-ethyl 2-arylpropanoates in 56-86percent yields via aryl group migration which are hydrolysed to 2-arylpropanoic acids, some of which are pharmaceutically important compounds.Overall isolated yields of 2-arylpropanoic acids are around 30-42percent based on the starting propiophenones over 5 steps.
- Uemura, Sakae,Fukuzawa, Shin-ichi,Yamauchi, Takayoshi,Hattori, Kaneaki,Mizutaki, Shoichi,Tamaki, Kentaro
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p. 1983 - 1987
(2007/10/02)
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- New Preparative Method for 2-Arylpropanoic Acids by Oxidative Aryl Migration in Aryl α-Seleno- and Aryl α-Telluro-ethyl Ketones
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Oxidation with m-chloroperbenzoic acid of the ethylene acetals of aryl α-phenylseleno- or aryl α-phenyltelluro-ethyl ketones prepared by treating the corresponding α-bromo compounds with diphenyl diselenide-sodium or diphenyl ditelluride-sodium, respectively, affords hydroxyethyl 2-arylpropanoates in moderate to good yields via aryl group migration.
- Uemura, Sakae,Fukuzawa, Shin-ichi,Yamauchi, Takayoshi,Hattori, Kaneaki,Mizutaki, Shoichi,Tamaki, Kentaro
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p. 426 - 427
(2007/10/02)
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- ONE-STEP SYNTHESIS OF SUBSTITUTED 2-ARYL-2-BROMOALKYL-1,3-DIOXOLANES
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Substituted phenones II reacted with ethylene glycol and pyridinium perbromide, phenyltrimethylammonium tribromide, or dioxane dibromide to give the corresponding α-bromoacetals I.The highest yields are obtained with dioxane dibromide, and a route is suggested in which the agent is generated in situ.The mass spectra of the compounds I are interpreted.
- Svoboda, Jiri,Palecek, Jaroslav,Dedek, Vaclav,Mostecky, Jiri
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p. 1515 - 1520
(2007/10/02)
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