Cesium carbonate → 2-Methyl-2-{4-[2-(5-methyl-2-biphenyl-4-yl-oxazol-4-yl)ethoxy]phenoxy}propionic acid ethyl ester

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A mixture of toluene-4-sulfonic acid 2-(2-biphenyl-4-yl --methyl-oxazol-4-yl)ethyl ester (14.9 g, 34.3 mmol), 2-(4-hydroxyphenoxy)-2-methyl propionic acid ethyl ester (American Home Products U.S. Pat. No. 3,795,691 (6.15 g, 27.4 mmol) and Cs2CO3 (12.0 g, 36.8 mmol) was heated at 55° C. in DMF (110 mL) for 18 h. The reaction was partitioned between ethyl acetate (160 mL) and H2O (180 mL), and the aqueous phase extracted with ethyl acetate (150 mL). The combined organic phases were dried (MgSO4) and concentrated under reduced pressure to an oil which was purified by column chromatography (600 mL SiO2, 10% ethyl acetate/hexanes to 20% ethyl acetate/hexanes) to provide 2-methyl-2-{4-[2-(5-methyl-2-biphenyl-4-yl-oxazol-4-yl)ethoxy]phenoxy}propionic acid ethyl ester (6.25 g, 47%) as a colorless, viscous oil: Rf=0.48 in 35% ethyl acetate/hexanes; 1H NMR (500 MHz, CDCl3) δ8.05-8.03 (m, 2H), 7.67-7.64 (m, 4H), 7.46 (m, 2H), 7.38 (m, 1H), 6.83-6.77 (m, 4H), 4.22 (q, J=9.2 Hz, 2H), 4.18 (t, J=8.8 Hz, 2H), 2.97 (t, J=8.8 Hz, 2H), 2.37 (s, 3H), 1.52 (s, 6H), 1.27 (t, J=9.2 Hz, 3H).

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