1-benzyl-4-methylpiperidin-3-one

Synthesis

A 640-L vessel was charged with SO3.pyridine (51.47 kg, 323.1 mol). DMSO (169 L) was added and the whole was heated slowly to 33 °C. After a solution was obtained, it was cooled to 25 °C. The TsOH salt of the amine (40.9 kg, 107.7 mol) was added into the vessel and suspended in DMSO (50 L). After the addition of Et3N (62 L, 43.8 mol), the SO3.pyridine solution in DMSO was added to the two-phase mixture in the vessel at such a rate as to keep the internal temperature below 25 °C. After 1 h of stirring at 22 °C, the reaction was 92% complete. The mixture was cooled to 10 °C and quenched with water (182 L) over a period of 40 min at such a rate as to keep the internal temperature below 17 °C; a 25% NH3 solution (16 L) was then added. After phase separation, the aqueous phase was extracted with three portions of toluene (3 × 60 L) while controlling the pH of the aqueous layer to 10 after each extraction. The combined organic phases (approximately 240 L) were extracted with water  (61 L), and the bright-orange solution was heated at 40−50 °C jacket temperature over 1 h while blowing a nitrogen stream into the solution via an immersing tube. Then, toluene (170 L) was stripped off at 50 °C to afford the ketone (50.84 kg, 93%) as an orange solution in toluene.

Uses

1-Benzyl-4-methylpiperidin-3-one is an intermediate used to prepare pyrrolo[2,3-d]pyrimidine compds. as inhibitors of protein kinases.