Benzylamine → N,N-dimethyl-N'-benzyl-1,2-cyclohexanediamine

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Reaction Steps

A solution of trans-2-dimethylaminocyclohexanol (58 g.; 0.405 mole) in 80 ml. of THF was added during 10 minutes to a suspension of NaH (17.05 g.; 0.405 mole of 57% dispersion in mineral oil) in 240 ml. of THF and the mixture was refluxed for 3 hours. It was cooled to 10°, and methanesulfonyl chloride (46.39 g.; 0.405 mole) was added dropwise during 30 minutes keeping the temperature below 15°. Benzylamine (86.79 g.; 0.81 mole) was then added during 5 minutes, the solvent was evaporated and heating continued at 95° for 16 hours. NaOH (500 ml. of 20% solution) was added and the mixture heated at 95° for 1 hour, cooled and extracted with ether (5×100 ml.). The ether solution was extracted with 10% HCl (6×100 ml.) and backwashed once with ether (discard). The acid extract was cooled, basified with 20% NaOH and extracted well with ether. The ether solution was washed with H2O, saturated salt solution, dried (MgSO4) and evaporated. Distillation at 0.4 mm gave 61 g. (65% yield) of N,N-dimethyl-N'-benzyl-1,2-cyclohexanediamine, b.p. 112°. It was identical by tlc to the sample prepared by the reaction of benzylamine with trans-2-chloro-dimethylaminocyclohexane.

Provenance & Evidence