反应详情

A solution of 4.0 g (0.02 mol) of 2-(4'-propylcyclohexyl)propane-1,3-diol, 5.1 g (0.025 mol) of 4-bromo-3-fluorobenzaldehyde, and 0.2 g of TsOH in 100 cm3 of dichloromethane was refluxed over a hot water bath fitted with a Dean-Stark trap for 3 hours and the water formed was continuously removed from the reaction system. The resulting solution was washed with water and dichloromethane was distilled off. The residue was recrystallized from acetone to yield 6.2 g (0.016 mol) of 2-(4'-bromo-3'-fluorophenyl)-5-(trans-4'-propylcyclohexyl)-1,3-dioxane. This compound contained about 10% of the cis isomer of the 1,3-dioxane ring.

1. customfitted with a Dean-Stark trap for 3 hours
2. customwas continuously removed from the reaction system
3. washThe resulting solution was washed with water and dichloromethane
4. distillationwas distilled off
5. customThe residue was recrystallized from acetone