951 mg (10.0 mmol) of 2-aminopyrazine were dissolved together with 1.31 g (10.0 mmol) of 1-phenylethylisonitrile and 1.08 ml (10.0 mmol) of 5-bromothiophene-2-carbaldehyde in chloroform (24 ml). After addition of perchloric acid (1.00 ml), the mixture was stirred at RT for 5 d. The mixture was then combined with a sat. aq. sodium carbonate solution and the phases were separated. The aqueous phase was extracted with DCM. The combined organic phases were washed with a sat. aq. sodium carbonate solution and dried over magnesium sulfate, filtered and evaporated under a vacuum. After carrying out column chromatography (EA/DCM 1:1) with the group, 831 mg (2.1 mmol, 21% of theoretical) of [2-(5-bromothiophen-2-yl)-imidazo[1,2-a]pyrazin-3-yl]-(1-phenyl-ethyl)-amine were obtained.
