反应详情

A mixture of 4-(4-chlorophenyl)benzaldehyde (21.6 g.), 2-hydroxy-2-methylpropionic acid (10.2 g.) and cationic sulphonated polystyrene ion exchange resin (`AMBERLITE` *IR 120, free acid form; 2.0 g.) in chlorobenzene (125 ml.) was heated under reflux for 24 hours with continuous removal of water by azeotropic distillation. The mixture was cooled and the resin was separated by filtration. Pyridine (3 ml.) was added to the filtrate which was then evaporated. The residue was dissolved in hot 2-propanol (200 ml.). A small quantity of insoluble material was removed by filtration and the subsequent filtrate was allowed to cool to give 2-[4-(4-chlorophenyl)phenyl]-5,5-dimethyl-1,3-dioxolan-4-one (11.8 g.), m.p. 108°-110° C.

1. temperatureThe mixture was cooled
2. customthe resin was separated by filtration
3. additionPyridine (3 ml.) was added to the filtrate which
4. customwas then evaporated
5. dissolutionThe residue was dissolved in hot 2-propanol (200 ml.)
6. customA small quantity of insoluble material was removed by filtration
7. temperatureto cool