[CH2:1]([CH:4]1[CH2:9][CH2:8][CH:7]([C:10]([OH:12])=[O:11])[CH2:6][CH2:5]1)[CH2:2][CH3:3].[Br:13][CH2:14][C:15]([CH3:19])([CH3:18])[CH2:16]O.C1(C)C=CC(S(O)(=O)=O)=CC=1>C1(C)C=CC=CC=1>[Br:13][CH2:14][C:15]([CH3:19])([CH3:18])[CH2:16][O:11][C:10]([CH:7]1[CH2:8][CH2:9][CH:4]([CH2:1][CH2:2][CH3:3])[CH2:5][CH2:6]1)=[O:12]4-Propyl-cyclohexanecarboxylic acid (10.0 g, 58.0 mmol), 3-bromo-2,2-dimethyl-propan-1-ol (10.0 g, 59.9 mmol) and a catalytic amount of para-toluene sulphonic acid are stirred under reflux in toluene (300 ml) in a flask equipped with Dean-Stark apparatus over night. The solution is allowed to cool to room temperature, is washed with aqueous sodium carbonate and water, dried and evaporated to dryness. Purification is achieved by filtration through a silica pad using petrol as eluant. Evaporation of the appropriate fractions gives 4-propyl-cyclohexanecarboxylic acid 3-bromo-2,2-dimethyl-propyl ester as a liquid. The structure is confirmed by GCMS.
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