反应详情

Methyl 5-(2,5-dichlorophenyl)pentanoate (1.10 g, 4.2 mmol) was dissolved in 20 ml tetrahydrofuran and 7 ml methanol. 1N LiOH (12 ml) was added dropwise and the reaction was stirred at room temperature for 2 days. The reaction was worked-up by acidification with 2N HCl and removal of most of the tetrahydrofuran and methanol on a rotary evaporator followed by extraction of the aqueous residue with ethyl acetate. The organic phase was washed with water and saturated brine, dried over anhydrous sodium sulfate and concentrated to a residue. Flash chromatography (silica gel; hexane/toluene (19/1) with 1% acetic acid) of the residue gave 725 mg (70%) of a white solid. 1H NMR (200 MHz, CD3OD) delta=7.30-7.26 (m, H3, H6), 7.14 (dd, J=2.6, 8.4 Hz, H4), 2.70 (t, J=7.2 Hz, Ar-CH2 --), 2.30 (t, J=7.0 Hz, --CH2 --COOH), 1.67-1.57 (m, --CH2 --CH2 --CH2 --CH2 --); MS (EI, m/z (relative intensity)) 248 (29), 246 (M+·, 45), 167 (31), 165 (97), 161 (66), 159 (100); exact mass calculated for C11H12Cl2 O2, [M]+· 246.0213, found 246.0210.

1. customThe reaction was worked-up by acidification with 2N HCl and removal of most of the tetrahydrofuran and methanol
2. customon a rotary evaporator
3. extractionfollowed by extraction of the aqueous residue with ethyl acetate
4. washThe organic phase was washed with water and saturated brine
5. dry with materialdried over anhydrous sodium sulfate
6. concentrationconcentrated to a residue