Piperidine → HCID 853659, compound

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Reaction Steps

23.8 g of cyclohexyl isocyanate (0.190 mol) are added dropwise to a solution of 18.62 g of piperidine (0.219 mol) in 360 ml of hexane, and then the cloudy mixture is refluxed for 2 h and then cooled and filtered, to give 39.3 g of pure N-cyclohexylpiperidine-1-carboxamide (yield 98.3%). 12 g of POCl3 (78 mmol) are added, over 1 h, to a suspension of 15.05 g of said N-cyclohexylpiperidine-1-carboxamide (71.6 mmol) in 65 ml of dry toluene, and then, after a few hours at 20° C., 18.1 g of N-butyl-N-ethylamine (0.179 mmol) are added over 2 h, and then, after a further 2 h at 20° C., 50 ml of water are added. 49 g of 35% sodium hydroxide are then added while cooling, and the two-phase medium is then extracted with diisopropyl ether. After drying and evaporation to dryness, the oil obtained, 20 g, is distilled at 185° C. under 1 mbar, to give 17 g of the expected guanidine (yield 81%).

Provenance & Evidence