Ether, ethyl ethynyl → 3-(2',4'-Difluoro-4-biphenylyl)-2-butenoic acid ethyl ester

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Reaction Steps

A solution of 23.2 g. of 4-acetyl-2',4'-difluorobiphenyl in 50 ml. of THF and 50 ml. of ether is added slowly dropwise to a solution of 17.5 g. of ethoxyethinylmagnesium bromide in 200 ml. of ether, prepared by reacting ethoxyacetylene with ethyl magnesium bromide. The mixture is stirred for 1 hour at 20°. The reaction product is hydrolyzed with ice water/ammonium chloride and extracted with ether. The combined ether extracts are dried over MgSO4 and evaporated. Residual 1-ethoxy-3-(2',4'-difluoro-4-biphenylyl)-butyn-3-ol is dissolved in 200 ml. of 95% ethanol and 0.05 g. of solid CO2 is added to the solution and the mixture is left to stand for 12 hours at 20°. The customary work up gives 3-(2',4'-difluoro-4-biphenylyl)-2-butenoic acid ethyl ester, m.p. 54°-56°.

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