Triethylamine → HCID 178469368, compound

Formamidine hydrochloride (2.0 g, 45.4 mmol) and diethyl 2-butynedioate (7.23 mL, 45.4 mmol) were added together in acetonitrile (85 mL) and the resulting mixture was treated dropwise with triethylamine (6.33 mL, 45.4 mmol). The resulting mixture was heated under reflux for 4 hours. The reaction mixture was allowed to cool to room temperature, further cooled in an ice bath and the resulting solid was collected by filtration and discarded. The filtrate was evaporated under reduced pressure and the residue purified by column chromatography (Biotage SP4) eluting with a gradient of 0-100% ethyl acetate and iso-hexane. Product containing fractions were combined and evaporated under reduced pressure to give the title compound as an off white solid (0.995 g);