Lawesson's reagent → Thiobutyrylamino-acetic acid methyl ester

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Reaction Steps

A solution of the product of Example 5A (0.774 g, 4.862 mmol) in anhydrous THF (50 mL) was treated with Lawesson reagent (1.338 g, 3.209 mmol), then heated at reflux under a nitrogen atmosphere for 30 minutes. The reaction was cooled to 0° and a saturated aqueous sodium bicarbonate solution (40 mL) was slowly added dropwise. The mixture was stirred at room temperature for 15 minutes, and then extracted with ethyl acetate (100 mL), and the organic extract washed with saturated aqueous sodium bicarbonate (50 mL), water (2×25 mL), and brine. Dried the organic phase over anhydrous sodium sulfate, filtered, and concentrated under vacuum giving the title compound. Purification by silica gel flash chromatography with 1% ethyl acetate/methylene chloride afforded the title compound as a colorless oil (0.790 g, 4.508 mmol, 93%).

Provenance & Evidence