Methylamine → 3,5-Dimethyl 1-methyl-4-oxo-2,6-di-2-pyridinyl-3,5-piperidinedicarboxylate

Participants

Reaction Conditions

Reaction Steps

1st stage: 12.9 kg of dimethyl acetonedicarboxylate (97%; 72 mol) were dissolved in 52.5 l of isobutanol. The solution was cooled to 10° C. At this temperature, 15.4 kg of pyridine-2-aldehyde (14.4 mol) were added dropwise and the mixture was stirred for a further 10 minutes. Subsequently, 5.59 kg of methylamine (40% in water, 72 mol) were added dropwise to this mixture at such a rate that the temperature could be maintained with uniform cooling. The reaction mixture was stirred at 10° C. for a further 90 minutes. After the reaction time had ended, the mixture was heated to 40-45° C. and 6.6 kg of water phase were separated out under reduced pressure at internal temperature 40-45° C. with the aid of a water separator. The mixture was then vented and cooled to 5-10° C. The product was filtered off and washed with 7.5 l of isobutanol. The moist product was dried at 50° C. under reduced pressure. 24.3 kg (88%) of 1-methyl-2,6-dipyridyl-3,5-di(methoxy-carbonyl)-4-piperidone were obtained as a white-beige powder.

Provenance & Evidence