[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].CN(C1C=CC=CN=1)C.C1(N=C=NC2CCCCC2)CCCCC1>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-methylphenylacetic acid, 1.13 l (12 mol) of tert-butanol and 90 g (0.74 mol) of dimethylaminopyridine 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 washed with 200 ml of dichloromethane, and the organic phase is washed twice each with 500 ml of 2M hydrochloric acid and water. The organic phase is dried using sodium sulphate, concentrated and distilled.
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