Benzaldehyde → 5,5-Bis(bromomethyl)-2-phenyl-1,3-dioxane

Reaction equation

[Br:1][CH2:2][C:3]([CH2:8][Br:9])([CH2:6][OH:7])[CH2:4][OH:5].[CH:10](=O)[C:11]1[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=1.S(=O)(=O)(O)O>C1C=CC=CC=1>[Br:1][CH2:2][C:3]1([CH2:8][Br:9])[CH2:6][O:7][CH:10]([C:11]2[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=2)[O:5][CH2:4]1

Participants

Procedure

2,2-Bis(bromomethyl)propane-1,3-diol (250 g) and benzaldehyde (110 g) were added to benzene (500 cm3) containing concentrated sulphuric acid (2 cm3) and the mixture boiled. Water was removed using a Dean Stark apparatus. After about 6 hours the reaction was complete. The mixture was cooled and the sulphuric acid neutralised by the addition of excess sodium bicarbonate. The resulting solution was filtered and the benzene removed under reduced pressure to give an oil which solidified on standing. Recrystallisation from petroleum ether gave the 1,3-dioxane (296 g) as a white solid (m.p. 66° C.).