Add triethylamine drop wise (3 equiv) to a suspension of 1-(3-methyl-5-nitro-pyridin-2-yl)-piperazine; hydrochloride (6.91 g, 24.13 mmol) in DCM (120 mL). Add 2,6-difluorobenzoylchloride (1 equiv.) Stir the mixture at room temperature overnight. Add additional 2,6-difluorobenzoylchloride (1.6 mL) and triethylamine (1.5 equiv.) to run reaction to completion. Allow the reaction to stand overnight. Dilute with DCM and extract several times with water. Dry the organic layer over Na2S2O4, filter, and remove solvent under reduced pressure. Wash solid several times with hexane to obtain. 8.08 g of (2,6-difluoro-phenyl)-[4-(3-methyl-5-nitro-pyridin-2-yl)-piperazin-1-yl]-methanone (93% yield). ES+(m/z): 363 [M+1]
