Ethyl Acetate → 4-Tert-butylbenzoyl isothiocyanate

To a stirred solution of 4-tert-butylbenzoyl chloride (6 g, 198 mmol) in acetone (250 mL) was added ammonium thiocynate (28 g, 237 mmol). The resulting yellow suspension was stirred at room temperature for 2 hours, condensed to dryness and then reconstituted through the addition of ethyl acetate (200 mL). The organic portion was washed with a saturated sodium bicarbonate solution (2×200 ml) and brine (200 mL). The resulting organic phase was dried over anhydrous sodium sulfate and concentrated to a sticky liquid. The residue was chilled in a −10° C. freezer to give 37 grams of Intermediate A as a yellow solid (88%).