[O:1]1CCO[CH:2]1[C:6]1[CH:11]=[CH:10][C:9]([C:12]2(O)[CH2:17][CH2:16][CH2:15][CH2:14][CH2:13]2)=[CH:8][CH:7]=1.C1(C)C=CC(S(O)(=O)=O)=CC=1.C(OCC)(=O)C.C(=O)([O-])O.[Na+]>C1(C)C=CC=CC=1>[C:12]1([C:9]2[CH:8]=[CH:7][C:6]([CH:2]=[O:1])=[CH:11][CH:10]=2)[CH2:17][CH2:16][CH2:15][CH2:14][CH:13]=1
1-(4-[1,3]Dioxolan-2-yl-phenyl)cyclohexanol (45 g) and p-toluenesulfonic acid (3.4 g) in 300 mL of toluene were refluxed for 3 hours under Dean-Stark conditions. After cooling, ethyl acetate and a saturated sodium hydrogen carbonate solution were added. The organic layer was washed twice with water, dried (magnesium sulphate), filtered and concentrated in vacuo. The residual oil was dissolved in glacial acetic acid (250 mL) and 1 M hydrochloric acid (25 mL) was added and the mixture was stirred at 50° C. for 2 hours. After cooling, the mixture was concentrated in vacuo. The residual oil was partitioned between ethyl acetate and water. The organic phase was washed three times with water, dried (magnesium sulphate), filtered and concentrated in vacuo. The residual oil was distilled in vacuo and the fraction boiling at 120-130° C. (0.2 mmHg) was collected to afford 4.7 g of the title compound.
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