Sulfuric Acid → Z-Asn(trt)-OH

Participants

Reaction Steps

A mixture of 13.3 g of Z-Asn-OH (50 mmol), 26 g of triphenylmethanol (100 mmol), 150 ml of acetic acid and 9.5 ml (100 mmol) of acetic anhydride is stirred at 50° for 15 minutes. Addition of 0.25 ml of conc. sulfuric acid produces, after 5 minutes, a clear yellow solution. After 11/2 hours, it is cooled and poured into 1.5 liters of ice-water. The precipitate is filtered off, thoroughly washed with water and dissolved in about 500 ml of ethyl acetate. The organic phase is washed with a saturated aqueous sodium chloride solution, dried over sodium sulfate and concentrated under reduced pressure to 250 g. Z-Asn(Trt)-OH is induced to crystallize by addition of 125 ml of hexane, m.p. 195°-196°.

Provenance & Evidence