N-Methylcyclohexylamine → 1,3-dicyclohexyl-1-methylurea

Participants

Reaction Steps

A solution of 19.12 g of N-methyl-N-cyclohexylamine (0.169 mol) in 160 ml of hexane is admixed dropwise with 18.38 g of cyclohexyl isocyanate (0.147 mol) and then the cloudy mixture is heated at reflux for 2 hours, then evaporated to dryness to give 35 g of crude N,N′-dicyclohexyl-N-methylurea. A suspension of 17 g of this crude product (71.33 mmol) in 65 ml of dry toluene is admixed with 12 g of POCl3 (78 mmol) over 1 hour, and then, after a number of hours at 20° C., 15.5 g of N-butyl-N-methylamine (0.178 mmol) are added over 2 hours, and then, after a further 2 hours at 20° C., 50 ml of water are added. 49 g of 35% sodium hydroxide solution are then added while cooling, after which the two-phase mixture is extracted with diisopropyl ether. Following drying and evaporation to dryness, the oil obtained, 26.5 g, is distilled at 180° C. under 1 mbar to give 21.25 g of the expected guanidine (97% yield).

Provenance & Evidence