反应详情

A solution of 2-(4-{2-[2-(4-bromophenyl)-5-methyloxazol-4-yl]ethoxy}phenoxy)-2-methyl-propionic acid ethyl ester (0.907 mmol) (see Ex. 2, part B) and 1-naphthaleneboronic acid (0.998 mmol) in toluene:ethanol (18.2 mL of a 1:1 solution) was treated with Na2CO3 (aq) (0.906 mL of a 2M solution). A nitrogen atmosphere was applied, Pd(PPh3)4 (52.5 mg) was added, and the orange mixture was heated at reflux for 2 h. After cooling to room temperature, the mixture was partitioned between ethyl acetate (20 mL) and H2O (30 mL). The layers were separated, and the aqueous phase was back-extracted with ethyl acetate (2×10 mL). Combined organic phases were washed with brine (20 mL), dried over Na2SO4, and concentrated. The product was purified by silica gel chromatography (20 g SiO2, 3:7 ethyl acetate:hexanes) to give the desired product in 87% as an orange oil; Rf=0.46 in 1:4 ethyl acetate:hexanes; 1H NMR (400 MHz, CDCl3) δ8.09 (d, J=8Hz, 2H), 7.92-7.82 (m, 3H), 7.59-7.40 (m, 6H), 6.81-6.72 (m, 4H), 4.22-4.17 (m, 4H), 2.98 (t, 2H), 2.38 (s, 3H), 1.46 (s, 6H), 1.22 (t, 3H); MS (EI) 536.3 (M+H)+.

1. temperaturethe orange mixture was heated
2. temperatureat reflux for 2 h
3. customthe mixture was partitioned between ethyl acetate (20 mL) and H2O (30 mL)
4. customThe layers were separated
5. extractionthe aqueous phase was back-extracted with ethyl acetate (2×10 mL)
6. washCombined organic phases were washed with brine (20 mL)
7. dry with materialdried over Na2SO4
8. concentrationconcentrated
9. customThe product was purified by silica gel chromatography (20 g SiO2, 3:7 ethyl acetate:hexanes)