Sulfuric Acid → 2-Tert-butyl-5-nitroaniline

Participants

Reaction Steps

Concentrated H2SO4 (1 L) was cooled to −10° C. with a dry ice/i-PrOH bath in a 2 L 3-neck round bottom flask fitted with a mechanical stirrer and temperature probe. 2-t-Butylaniline (109 g, 730 mmol) was added, giving a clumpy solid. Once the temperature stabilized at −10° C., KNO3 (101 g, 1001 mmol) was added portion wise, as a solid, for 4 h, maintaining the temperature between −20 and −5° C. Once all of the KNO3 was added, the reaction was stirred overnight with gradual warming to RT. The reaction was quenched by diluting with water and extracted with EtOAc (3×). The EtOAc extracts were washed multiple times with saturated NaHCO3(aq), until gas evolution ceased, then with brine. The EtOAc extracts were combined, dried over anh. Na2SO4, filtered and concentrated under reduced pressure giving a black oil. The oil was eluted through a 36×7 cm column of silica gel with a 5%; 10%; 15%; 25%; and 50% EtOAc:Hexanes step gradient (2 L each step) giving a red solid.

Provenance & Evidence