[CH2:1]([O:3][C:4]([CH:6]1[CH2:11][CH2:10][C:9](=[O:12])[CH2:8][CH2:7]1)=[O:5])[CH3:2].[CH2:13](O)[CH2:14][OH:15].C1(C)C=CC(S(O)(=O)=O)=CC=1.C(OCC)C>C1(C)C=CC=CC=1>[CH2:1]([O:3][C:4]([CH:6]1[CH2:11][CH2:10][C:9]2([O:15][CH2:14][CH2:13][O:12]2)[CH2:8][CH2:7]1)=[O:5])[CH3:2]4-oxo-cyclohexanecarboxylic acid ethyl ester (52.8 g, 0.31 mole, Merck, Order No. 814249), ethylene glycol (67.4 g, 1.08 mole) and p-toluenesulfonic acid (0.7 g) in toluene (160 ml) were stirred for 20 hours at RT, and the reaction solution was poured into diethyl ether (300 ml) and washed with water, sodium hydrogen carbonate solution and sodium chloride solution. The solution was dried (Na2SO4), concentrated by evaporation in vacuo, and the remaining colorless liquid was processed further without purification.
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