[CH3:1][C:2]1[CH:7]=[CH:6][C:5]([CH2:8][C:9]([OH:11])=[O:10])=[CH:4][CH:3]=1.[C:12](O)([CH3:15])([CH3:14])[CH3:13].C1(N=C=NC2CCCCC2)CCCCC1>CN(C1C=CN=CC=1)C.ClCCl>[CH3:1][C:2]1[CH:3]=[CH:4][C:5]([CH2:8][C:9]([O:11][C:12]([CH3:15])([CH3:14])[CH3:13])=[O:10])=[CH:6][CH:7]=1450 g (3 mol) of 4-methylphenyl-acetic acid (Aldrich), 1.13 l (12 mol) of tert-butanol and 90 g (0.74 mol) of 4-(N,N-dimethylamino)pyridine are dissolved in 2 l of dichloromethane. After addition of 680 g (3.3 mol of dicyclohexylcarbodiimide, dissolved in 400 ml of dichloromethane, the mixture is stirred at 25° C. for 20 h, the precipitated urea is filtered off with suction and flashed with 200 ml of dichloromethane, and the organic phase is washed twice each with 500 ml of 2 M hydrochloric acid and water. The organic phase is concentrated and distilled.
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