Diisopropylethylamine → 5-(3-Fluoro-phenylethynyl)-pyridine-2-carboxylic acid tert-butyl-ethyl-amide

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Reaction Steps

(100 mg, 0.41 mmol) 5-(3-Fluoro-phenylethynyl)-pyridine-2-carboxylic acid (Example 1, step 2) was dissolved in dioxane (1 ml) and Hunig's Base (217 μl, 1.24 mmol, 3 equiv.), tert.-butylethylamine (63 mg, 0.62 mmol, 1.5 equiv.) and TBTU (146 mg, 0.45 mmol, 1.1 equiv.) were added at room temperature. The mixture was stirred for 16 hours at room temperature. The reaction mixture was evaporated and extracted saturated NaHCO3 solution and two times with a small volume of dichloromethane. The crude product was purified by flash chromatography by directly loading the dichloromethane layers onto a silica gel column and eluting with an ethyl acetate:heptane gradient 0:100 to 0:100. The desired 5-(3-fluoro-phenylethynyl)-pyridine-2-carboxylic acid tert-butyl-ethyl-amide (102 mg, 76% yield) was obtained as a light yellow oil, MS: m/e=325.3 (M+H+).

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