Reactions of Halogenophenols

The reactions of halogenophenols are discussed in this section dealing with fiuoro, chloro, bromo and iodophenols. Certain of these reactions would of course take place in the absence of the halogen substituent and it is perhaps remarkable that many of the cydisations described occur despite the deactivating influence of that group. 

Methyl 2-(3-fluoro-4-hydroxyphenyl)propionate in dimethylformamkje containing potassium iodide and carbonate when treated slowly with 

3-chloro-3-methyl-1-butyne gave the corresponding ether by reaction at 75 C during 18 hours in 75% yield. Cydisation of this was effeded in N,N-dimethylaniline by refluxing at 215 C for 3 hours to give an 80% yield of methyl 2-(2,2-dimethyl-8-fluoro-1,2-benzopyran- -yl)propionate (ref.38). 

Perfluoro-1-naphthol was added to dimethylformamide containing graphite into which a little potassim fluoride had been intercalated and after the mixture had been stirred for 5-10 mins, a dimethylformamide solution of pentafluoropyridine was introduced. 

The mixture was then heated at 80°C for 5 hours to give perfluoro-1-naphthyl perfluoro-4-pyridyl ether depided in 71% yield (ref.39). 

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