Sulfuric Acid → Methyl 4-aminophenylacetate hydrogensulfate

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反応条件

反応手順

The 4-aminophenylacetamide used in this example was obtained according to patent literature WO 02/08247 A2 or WO 03/051909 A2. Procedure was as follows: Methanol (200 mL) was charged to 4-aminophenylacetic acid (Aldrich) (25 g, 0.165 mol). Sulfuric acid (18 mL concentrated, 0.648 mol) was added maintaining the temperature <20° C. The mixture was then refluxed for one hour and concentrated by distillation at atmospheric pressure until the volume of 140 mL. The mixture was then cooled to 50° C. and tert-buthyl methyl ether (300 mL) was added maintaining the temperature above 45° C. The mixture was gradually cooled to 0-5° C. and held at this temperature for 1 hour. The resultant crystalline product was isolated by filtration and washed with cold methanol:tert-butyl methyl ether (20 mL:55 mL) and cold tert-butyl methyl ether and then dried under vacuum to give methyl 4-aminophenylacetate hydrogensulfate (35.3 g, 80% yield).

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