In a 500-mL flask equipped with a septum inlet, magnetic stirring bar, and condenser leading to a mercury bubbler was placed 22.8 g (0.12 mol) of [2-(aminomethyl)4-(trifluoromethyl)phenyl]amine in 218 mL dimethoxyethane. To this reaction flask with stirring was added 26 mL (0.24 mol) N-methylmorpholine and 24 mL (0.13 mol) 3,5-bis(trifluoromethyl)benzyl bromide. The contents were heated to and maintained at reflux under nitrogen for 12 hours. Afterwards, TLC analysis revealed a minor amount of starting material remaining. The contents were cooled to room temperature, diluted with ether and transferred to a separatory funnel and washed with water and brine, dried over magnesium sulfate, filtered and concentrated to afford an oil. The oil was dissolved in hexane, cooled in an ice bath and acetic acid was added slowly while stirring to precipitate solids. The solids were filtered, dissolved in ether, and cooled in an ice bath and stirred while saturated sodium bicarbonate was added slowly until basic. The contents were transferred to a separatory funnel and washed with brine, dried over magnesium sulfate, filtered, and concentrated to give 12 g [2-amino-5-(trifluoromethyl)benzyl][3,5-bis(trifluoromethyl)benzyl]amine as an orange oil. In addition the hexane mother liquor contained significant amounts of product and byproducts. This liquor was concentrated to yield dark yellow oil that was used without further purification in the following step.
