Regioselective Nucleophilic 1,4-Trifluoromethylation of 2-Polyfluoroalkylchromones with (Trifluoromethyl)trimethylsilane. Synthesis of Fluorinated Analogs of Natural 2,2-Dimethylchroman-4-ones and 2,2-Dimethylchromenes
摘要:
Reactions of 2-polyfluoroalkylchromones with (perfluoroalkyl)trimethylsilanes proceed as a 1,4-nucleophilic perfluoroalkylation to give 2,2-bis(polyfluoroalkyl)chroman-4-ones with high regioselectivity and good yields after acid hydrolysis. Oxidation of 6-methyl-2,2-bis(trifluoromethyl)chroman-4-one with a mixture of K2S2O8 and CuSO4 in aqueous acetonitrile leads to fluorinated analogues of natural lactarochromal and the corresponding acid. Reduction of substituted 2,2-bis(trifluoromethyl)chroman-4-one with sodium borohydride in methanol and subsequent dehydration of chromanols in refluxing xylene in the presence of p-toluene sulfonic acid gives 2,2-bis(trifluoromethyl)chromenes, which are fluorinated analogues of natural precocenes.
7-Polyfluoroalkylnorkhellins: synthesis and reactions with alkyl mercaptoacetates
摘要:
New R-F-containing benzofuran derivatives of 2-oxa-7-thiabicyclo[3.2.1]octane and dihydrothienopsoralens were synthesized from 7-polyfluoroalkylnorkhellins and alkyl mercaptoacetates. (C) 2003 Elsevier Science Ltd. All rights reserved.
Synthesis of 3-alkylamino-3-(2-hydroxyaryl)-1-polyfluoroalkylprop-2-en-1-ones and 2-polyfluoroalkyl-4H-chromen-4-imines
作者:V. Ya. Sosnovskikh、B. I. Usachev
DOI:10.1023/b:rucb.0000030815.40767.a1
日期:2004.2
Condensation of Schiff"s bases (prepared from 2-hydroxy- or 2-hydroxy-5-methylacetophenones and primary amines) with ethyl polyfluoroalkanoates in the presence of LiH in THF affords 3-alkylamino-3-(2-hydroxyaryl)-1-polyfluoroalkylprop-2-en-1-ones, which undergo cyclization in acidic media into 2-polyfluoroalkyl-4H-chromen-4-iminium salts. When neutralized with aqueous ammonia, the latter give 2-po
Synthesis and some properties of 2-(polyfluoroalkyl)chroman-4-ols and 2-(polyfluoroalkyl)chroman-4-ones
作者:V. Ya. Sosnovskikh、R. A. Irgashev、B. I. Usachev
DOI:10.1007/s11172-009-0345-3
日期:2009.12
Reduction of 2-(polyfluoroalkyl)chromones by sodium borohydride in methanol gives cis-2-(polyfluoroalkyl)chroman-4-ols in high yields, which are easily oxidized by chromic acid to 2-(polyfluoroalkyl)chroman-4-ones. The latter are of interest as the starting materials for the preparation of novel RF-containing chromane derivatives.
Reactions of 7-polyfluoroalkylnorkhellins with alkyl mercaptoacetates: a simple synthesis of dihydrothienopsoralens and benzofuran derivatives of 2-oxa-7-thiabicyclo[3.2.1]octane
作者:Vyacheslav Ya Sosnovskikh、Boris I Usachev
DOI:10.1016/s0040-4039(01)00948-0
日期:2001.7
New fluoro-containing derivatives of khellin were synthesized from 7-polyfluoroalkylnorkhellins and alkyl mercaptoacetates. (C) 2001 Elsevier Science Ltd. All rights reserved.