[CH2:1]([OH:6])[CH2:2][CH2:3][CH2:4][OH:5].[O:7]1[CH:12]=[CH:11][CH2:10][CH2:9][CH2:8]1.C1(C)C=CC(S([O-])(=O)=O)=CC=1.[NH+]1C=CC=CC=1>ClCCl.O1CCCC1>[O:7]1[CH2:12][CH2:11][CH2:10][CH2:9][CH:8]1[O:5][CH2:4][CH2:3][CH2:2][CH2:1][OH:6]To a solution of 100.0 g of 1,4-butanediol and 20 ml of 3,4-dihydro-2H-pyrane in 80 ml of dichloromethane and 140 ml of tetrahydrofuran, 1.8 g of pyridinium p-toluenesulfonate was added. After stirring at room temperature for 18 hours, the solvent was evaporated under reduced pressure. The residue was extracted three times with diethyl ether after adding saturated brine. After the extract was washed with a small amount of water and dried over anhydrous magnesium sulfate, the solvent was evaporated to obtain 35.98 g of the desired crude product as a colorless oily substance.
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