To a solution of 13.6 g (0.08 mol) of N-hexylpiperazine and 8.1 g (11.2 ml),
(0.08 mol) of triethylamine in 120 ml toluene, was added 15.6 g (0.08 mol) of
N-isobutyl-benzimidoyl chloride over a period of 15 minutes. The reaction
mixture was stirred at room temperature for a period of 2 hours. The
triethylamine hydrochloride was filtered off and the filtrate concentrated under
vacuum. The residual oily base was washed with 20 ml water, extracted with
50 ml ether and dried over anhydrous magnesium sulfate. The dry ethereal
solution was then added to a solution of 18.6 g (0.16 mol) maleic acid in 800
ml ether to obtain the dimaleate salt. Two recrystallizations from ethanol
yielded 22.5 g (50.2%) of N-[(4-hexyl-1-piperazinyl)phenylmethylene]-2-
methyl-1-propanamine product, M.P. 175°-176°C.
