98841-70-4Relevant articles and documents
Isolement et identification des impuretes formees au cours de la synthese industrielle de la fluoro-5 hydroxy-2 butyrophenone par transposition de Fries
Martin, Robert
, p. 239 - 242 (2007/10/02)
P-fluorophenyl n-butyrate dissolved in 1,2-dichloro-ethane is rearranged via an Aluminium chloride catalysed Fries rearrangement at a temperature of 100 deg C.Together with expected compound (85percent) four other ketones have been isolated.Formation of these ketones can be explained by reaction of Aluminium chloride on 1,2-dichloroethane producing vinyl chloride.One of them, the 1-(5-fluoro-2-hydroxyphenyl)-trans-1-hexen-3-one stems from the p-fluorophenol produced by heterolytic cleavage of the ester.It is then alkylated in the ortho position of the hydroxyl group.Formation of the three other ketones proceeds through alkylation of the ester in the meta position prior to the Fries reaction.Therefore, these ketones have an alkyl radical in meta position of the hydroxyl group.The simplest of them is 4'-ethyl-5'-fluoro-2'-hydroxy-butyrophenone.The two others are diketones, belonging to 1,1-diphenylethane series.An ethylidene bridge is created between the two aromatic rings.Total yield of identified compounds exceeds 96percent.No fluorine elimination has been noticed.Involvement of 1,2-dichloroethane in the Fries reaction is therefore confirmed.
