4-Piperidinecarboxamide → 4-Cyanopiperidine

Participants

Reaction Steps

Thionyl chloride 232 gm (molar ratio thionyl chloride: piperidine-4-carboxamide is 2.53:1) is taken in a 500 ml four-necked reaction flask, fitted with glass agitator and a condenser. A vent is provided at the condenser top passing through a 10% diluted solution of caustic lye to neutralize the vent gases. Piperidine-4-carboxamide 100 gm is added lot wise with continuous stirring over a period of 30 minutes, temperature increased from 32° to 65° C. due to the exothermicity of the reaction. The reaction mixture is maintained at 65°-70° C. for 3-4 hours and a sample is drawn and analyzed, 4-cyanopiperidine 94.78% Area, Piperidine-4-carboxamide=Nil is obtained. The reaction mass is cooled to room temperature and poured over 400 gm crushed ice by maintaining the temperature at 0°-10° C. Then, 160 gm (46% solution) caustic lye is added to the above mass while maintaining the temperature between 15°-20° C. and the pH is adjusted between 12 and 13. The alkaline reaction mass is extracted with (400 ml×4) toluene. The organic layer is separated and the solvent is recovered by atmospheric distillation. The concentrated mass is distilled under high vacuum (4-6 mm Hg) to obtain 52.5 gm (molar yield=61%) 4-cyanopipeiridne with purity 99.75%.

Provenance & Evidence