Sulfate Ion → 4'-(Heptyloxy)[1,1'-biphenyl]-4-carboxylic acid

Participants

Reaction Steps

2,3-Difluorohydroquinone monobenzyl ether (prepared from 2,3-difluorophenol by the Elbs reaction, benzylation of the sulfate obtained as an intermediate, and acid cleavage of the sulfate) is reacted with DEAD/PPh3 and optically active ethyl lactate. The protecting group is subsequently removed hydrogenolytically. At 0° C., 0.01 mol of the compound obtained in this way and 0.01 mol of 4'-heptyloxybiphenyl-4-carboxylic acid are reacted dropwise with 0.01 mol of DCC dissolved in methylene chloride, with exclusion of moisture in methylene chloride in the presence of a catalytic amount of DMAP [sic]. The mixture is stirred at room temperature for 12 hours, the dicyclohexylurea which precipitates is removed by filtration, and the filtrate is worked up in a customary manner. The product is purified by chromatography, to give ethyl 2-[2,3-difluoro-4-(p-(p-heptyloxyphenyl)benzoyloxy)phenoxy]propionate.

Provenance & Evidence