[Cl:1][C:2]1[C:7]([Cl:8])=[C:6]([C:9](=[O:13])[CH2:10][CH2:11][CH3:12])[CH:5]=[CH:4][C:3]=1[OH:14].CC[O:17][C:18]([C:20]1(Br)[CH2:23][CH2:22][CH2:21]1)=[O:19].C(=O)([O-])[O-].[K+].[K+]>CN(C)C=O>[Cl:1][C:2]1[C:7]([Cl:8])=[C:6]([C:9](=[O:13])[CH2:10][CH2:11][CH3:12])[CH:5]=[CH:4][C:3]=1[O:14][C:20]1([C:18]([OH:19])=[O:17])[CH2:23][CH2:22][CH2:21]1A mixture of 2,3-dichloro-4-butyrylphenol (7 g, 0.03 mole), ethyl α-bromocyclobutanecarboxylate (10.23 g, 0.049 mole) and potassium carbonate (7.5 g, 0.054 mole) in N,N-dimethylformamide (60 ml) was stirred and heated at 65° C. for 18 hours. The reaction mixture was poured into ice water and the resulting mixture was extracted with ether. The ether extract was washed with a 1% sodium hydroxide solution, then with water and finally dried over MgSO4. The ether was evaporated in vacuo and the residue treated with acetic acid (60 ml) and 5% hydrochloric acid (15 ml). The mixture was stirred and refluxed overnight. The solvents were evaporated in vacuo. The residue was chromatographed over a column containing silica gel (140 g) using methylene chloride/tetrahydrofuran/acetic acid 50/1/1 as the eluent. The pertinent fractions were united, treated with toluene and evaporated in vacuo to obtain 1-(2,3-dichloro-4-butyrylphenoxy)cyclobutane-1-carboxylic acid as a liquid whose identity was confirmed by NMR and purity by thin layer chromatography.
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