反应详情

To a mixture of 2-chloro-4-fluorobenzaldehyde (20.0 g, 0.13 mol, Aldrich) and malonic acid (26.2 g, 0.25 mol, Aldrich) in pyridine (100 ml) at 50° C. was added dropwise piperidine (10 ml). After 18 h at 70° C., the mixture was poured into an ice cold solution of concentrated HCl (120 ml) and water (1.5 L). The resulting solid was filtered and washed repeatedly with water to give 24.4 g (96%) of 2-chloro-4-fluoro-cinnamic acid as a white solid: Recrystallization of 1.5 g from acetone:water mixtures gave 1.1 g of 2-chloro-4-fluorocinnamic acid as a white solid: mp 243°-245° C.

1. filtrationThe resulting solid was filtered
2. washwashed repeatedly with water