Hydrochloric Acid → 2-(3,4-dichlorophenyl)pent-4-enoic Acid

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Reaction Steps

To a solution of methyl 2-(3,4-dichlorophenyl)pent-4-enoate (2.47 g, 9.53 mmol) in tetrahydrofuran (15.0 mL) was added a solution of lithium hydroxide monohydrate (2.00 g, 47.6 mmol) in water (15.0 mL). The mixture was vigorously stirred at rt for 12 hrs. The resulting mixture was acidified by addition of 12.0 M of hydrochloric acid in water (3.97 mL, 47.6 mmol) at 0° C., and extracted with EtOAc (×3). The combined organic layer was dried and concentrated to provide 2-(3,4-dichlorophenyl)pent-4-enoic acid as a yellow syrup (2.65 g, quantitative). 1H NMR (400 MHz, CDCl3) δ 7.45-7.35 (m, 2H), 7.21-7.11 (dd, J=8.3, 2.1 Hz, 1H), 5.76-5.59 (ddt, J=17.0, 10.2, 6.8 Hz, 1H), 5.14-4.99 (m, 2H), 3.65-3.56 (t, J=7.7 Hz, 1H), 2.88-2.74 (dt, J=14.8, 7.5 Hz, 1H), 2.58-2.43 (dt, J=14.3, 6.9 Hz, 1H).

Provenance & Evidence