[CH3:1][O:2][C:3](=[O:19])[CH:4]([C:12]1[CH:17]=[CH:16][C:15]([Cl:18])=[CH:14][CH:13]=1)[C:5]1[CH:10]=[CH:9][C:8]([Cl:11])=[CH:7][CH:6]=1.[Li+].[CH3:21]C([N-]C(C)C)C.IC>C1COCC1>[CH3:1][O:2][C:3](=[O:19])[C:4]([C:12]1[CH:17]=[CH:16][C:15]([Cl:18])=[CH:14][CH:13]=1)([C:5]1[CH:6]=[CH:7][C:8]([Cl:11])=[CH:9][CH:10]=1)[CH3:21]A solution of bis-(4-chloro-phenyl)-acetic acid methyl ester (1.19 g, 4.0 mmol) in THF (20 ml) was cooled to −78° C. under nitrogen. A solution of LDA (3.0 mL, 6.0 mmol, 2M in heptane/THF/ethylbenzene) was added over 5 minutes, then after a further 20 minutes, iodomethane (0.63 ml, 10.1 mmol) was added. After 4 hours the reaction was quenched by the addition of saturated ammonium chloride solution and allowed to warm to room temperature then concentrated in vacuo to remove organic solvents. The mixture was diluted with ethyl acetate/petrol 1:4 and washed with saturated ammonium chloride solution then brine, dried (MgSO4), filtered and concentrated to give a residue which was purified by column chromatography (SiO2), eluting with an ethyl acetate/petrol gradient (1% to 2%), to afford the title compound as a colourless oil (210 mg, 17%); LCMS (PS-B3) Rt 4.01 min, No Ionisation. 1H NMR (CDCl3) δ 1.88 (3H, s), 3.73 (3H, s), 7.11-7.14 (4H, m), 7.26-7.30 (4H, m).
Loading…
