ethyl 2-(2,6-dichlorophenyl)acetate

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 2,6-dichlorophenyl acetic acid (6.7 g, 0.033 mol) in dichloromethane (170 ml) was added triethylamine (5.9 ml, 0.043 mol), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (8.1 g, 0.043 mol) and 4-pyrrolidinopyridine (0.58 g, 0.004 mol). Ethanol (2.5 ml, 0.043 mol) was added dropwise and the solution stirred overnight at room temperature. After this time the mixture was washed with water (2×100 ml), 1M HCl (2×100 ml), aq. K2CO3 (sat.; 2×100 ml) and brine (100 ml). The organic phase was separated, dried (Na2SO4) and evaporated. The residue was chromatographed on silica, using petrol:ether (10:1) as the eluant, to give the ester (7.2 g, 94%) as a colourless oil which solidified on standing at 0° C. 1H NMR (360 MHz, d6 -DMSO) δ 1.26 (3H, t, J=7.1 Hz), 4.01 (2H, s), 4.18 (2H, q, J=7.1 Hz), 7.15 (1H, t, J=8.6 Hz), 7.32 (2H, d, J=8.6 Hz). After this time the mixture was washed with water (2×100 ml), 1M HCl (2×100 ml), aq. K2CO3 (sat.; 2×100 ml) and brine (100 ml) The organic phase was separated dried (Na2SO4) evaporated The residue was chromatographed on silica

Conditions: temp:120.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 2,6-Dichlorotoluene (2.4 g), ethanol (46 mg), di-tert-butyl peroxide (73 mg, 1 equivalent), and Pd(Xantphos)Cl2 (3.8 mg, 1 mol %) were added into a reaction kettle, into which 10 atm carbon monoxide was introduced. The reaction was heated to 120° C., and stirred at this constant temperature for 16 h. After the reaction was completed, carbon monoxide was discharged, and 84 mg ethyl 2,6-dichlorophenylacetate was obtained by column chromatography, in a yield of 72%. 1HNMR (400 MHz, CDCl3) δ 1.25 (t, J=7.2 Hz, 3H), 4.01 (s, 2H), 4.17 (q, J=7.2 Hz, 2H), 7.14-7.18 (m, 1H), 7.31-7.33 (m, 2H); 13CNMR (100 MHz, CDCl3) δ 14.2, 36.8, 61.1, 128.0, 128.9, 131.4, 136.1, 169.5; HRMS (ESI) calcd. for C10H10Cl2NaO2 [M+Na]: 254.9950. found: 254.9949. The ethyl 2,6-dichlorophenylacetate obtained was dissolved in 1,4-dioxane. 6 N sodium hydroxide solution was added, and the reaction was heated to 60° C. After 2 h of reaction, the pH value was adjusted to 1 by adding 2 N hydrochloric acid. After removing the organic solvent under reduced pressure, 71 mg product 2,6-dichlorophenylacetic acid was obtained by extraction with ethyl acetate, and the yield of hydrolysis was 95%. was introduced