Imination of 4-aminopyridine with salicylaldehydeImination of 4-aminopyridine with salicylaldehyde
SyntheticPage 649
Published Jul 24, 2013
A 250 mL round-bottom flask fitted with a PTFE stopcock sidearm was charged with a suspension of salicylaldehyde (2.440 g, 20.0 mmol) and 4-aminopyridine (0.940 g, 10 mmol) in dry toluene (200 mL). A Soxhlet extractor equipped with a dry paper thimble charged with excess powdered CaH2 and condenser was fitted. The condenser outlet was fitted with a T-joint allowing the reaction to be performed under an atmosphere of dry dinitrogen. The system was heated to reflux for 3 d. Toluene was removed to ca. 50 mL in vacuo under Schlenk conditions and the solution was left overnight. The resulting yellow precipitate was isolated by filtration (1.50 g, 75 %) and handled only under a dry atmosphere.