Methanol → Benzenebutanoic acid, gamma-oxo-, methyl ester

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반응 단계

To a 1.0 L round bottom flask was added 49.25 g (0.276 mol) of 3-benzoylpropionic acid. To this was added 700 mL of ACS methanol and the solution stirred until all of the acid had dissolved. To this solution was added approximately 2.0 mL of conc. H2SO4 and the reaction refluxed for 2.5 hours. The reaction can be monitored by HPLC. After the reaction was determined to be complete, the methanol was removed on the rotoevaporator and to the residual oil was added ethyl acetate (~500 mL). To the ethyl acetate layer was then added 150 mL of a saturated sodium carbonate solution. The layers were extracted and allowed to separate. The organic layer was then dried (MgSO4), filtered and concentrated to yield methyl 3-benzoylpropionate (1) as a light yellow oil. Yield 53.30 g; yield 100%; >97% cp. Lt bp 172-174° C. at 10 mm Hg.; 1H NMR ppm (δ), CDCl3, 7.98 (dd, 2H), 7.54 (m, 1H), 7.45(m, 2H), 3.70 (s, 3H, OCH3), 3.32 (t, 2H), 2.76 (t, 2H). 13C NMR ppm (δ), CDCl3 198.0 (C=O), 173.3 (CO2), 136.5 (q), 133.2, 128.6, 128.0, 51.7 (OCH3), 33.3, 28.0. IR oil cm-1 2952, 1737, 1687, 1596, 1449, 1358, 1221, 1168, 1001, 750, 691.

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