Benzene, acylation fluorination

The elimination of carbon monoxide from nonfluonnated acyl fluorides, however, does not result in a fluorine compound Although it was claimed earlier that benzoyl fluoride can be converted into fluorobenzene by using tns(triphenyl-phosphine)rhodium chloride, recent studies proved that the product is benzene and not fluorobenzene [91]... 

Members of this class usually have an amine and a fluorine atom on the benzene ring as well as other embellishments as in ofloxacin, a recent example. The preparation of ofloxacin starts with two enolate acylations. 

Parameters such as solvent, basic medium and reaction time, affecting the derivatization of alcohols and phenols with benzoyl chloride, were investigated. End analysis was by GC with UVD . a sensitive method proposed for trace determination of phenols in water consists of preconcentration by SPE with a commercial styrene-divinylbenzene copolymer, acylation with pentafluorobenzoyl chloride in the presence of tetrabutylammonium bromide and end analysis by GC with either ECD or ITD-MS. LOD was 3 to 20 ngL for ECD and 10 to 60 ngL for ITD-MS, with 500 mL samples . Acylation with the fluorinated glutaric acid derivative 43 was proposed for determination of urinary phenols, as indicative of exposure to benzene and other aromatic hydrocarbons. End analysis by GC-MS shows strong molecular ions of the derivatives by electron ionization. The proto-nated ions are the base peaks obtained by chemical ionization. LOD was 0.5 mgL and the linearity range 0-100 mg L for phenol . 

Ort/io-selectivity is generally observed in the reactions of 2,4-dichloro- and 2,4-difluoro-nitrobenzene with alkoxide and thiophenoxide ions [199]. Also in less activated systems, nucleophiles generated from phenols and thiophenols with potassium fluoride-alumina and 18-crown-6-polyether will react in DMSO with cyano- or nitro-substituted fluoro- or chloro-benzenes [200]. Interestingly, the reaction of difluorobenzenes with two diffoent alcohols can occur sequentially. Introduction of the first etho" function deactivates the ring, and use of more forcing conditions allows substitution of the second fluorine [201]. Consecutive displacements of fluorine and nitro groups have been observed in the reaction of ort/io-fluoronitrobenzene with chiral acyl bicyclic lactones in a highly enantioselective synthesis of spirooxindoles [202]. 

The synthetic methods and photoluminescent properties of new dendrimers with an electron-deficient fluorinated starburst oxadiazole core were discussed in the publication of Chen, Fan et al. [138], Here in the first, key stage the 1,3-dipolar cycloaddition occurred of 2,3,4,5,6-pentafluorobenzonitrile to NaNs along the known procedure (Demko-Sharpless) giving 5-(perfluorophenyl)-lH-tefrazole 158. In the next stage 5-(perfluorophenyl)-lH-tetrazole was acylated by benzene-l,3,5-tricarbonyl trichloride to obtain l,3,5-(5-perfluorophenyl-l,3,4-oxadiazol-2-yl)benzene 159. 

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