Triethylamine → HCID 178428962, compound

Participants

Reaction Steps

4-Imidazolecarboxylic acid (2 grams, 17.9 mmol) and thionyl chloride (5 mL, 68.5 mmol) were heated to reflux in anhydrous acetonitrile (50 mL) under nitrogen for 1 hour. Then all volatile was removed under vacuum. The conversion to acid chloride is almost quantitative. To a solution of imidazole acid chloride in anhydrous acetonitrile (10 mL) was added dropwise a solution of 2-amino-2-methyl-1-propanol) (2.1 g, 21.4 mmol) and triethylamine (3.0 mL, 21.4 mmol) in anhydrous acetonitrile (10 mL) at 0° C. under N2. After the addition, the ice-bath was removed and the mixture was stirred at room temperature for 5 hours. The white solid of triethylamine hydrochloride was filtered out. Solvent and excess aminoalcohol were removed under vacuum. Dark brown oil was obtained. The dark brown oil was dissolved in hot acetonitrile (20 mL). After the solution was cooled down, a solution of thionyl chloride (5 mL) in anhydrous acetonitrile (10 mL) was added dropwise at 0° C. After stirring at room temperature for 2 hours, all volatile was removed under vacuum. To the oily residue was added acetonitrile (20 mL) and 10% aqueous potassium carbonate solution (20 mL). The mixture was heated to reflux for 2 hours. Two layers were observed after the mixture was cooled down. The water layer was discarded. Sodium bicarbonate solution was added to the organic layer, and the resulting mixture was extracted with ethyl acetate 3 times. After drying over magnesium sulfate and removal of solvent, flash chromatography (ethyl acetate:methanol=4:1) yielded pure 2-(imidazol-4-yl)-4,4-dimethyloxazoline as brown oil (1.75 g, 60%). 1H NMR (acetone-d6) δ1.35 (s, 6H), 4.10 (s, 2H), 7.58(s, 1H), 7.85(s, 1H).

Provenance & Evidence