Sulfuric Acid → Z-Gln(Trt)-OH

Participants

Reaction Steps

1.1 ml of acetic anhydride (12 mmol) are added to a mixture of 2.8 g of Z-Gln-OH (10 mmol), 5.2 g of triphenylmethanol (20 mmol) in 30 ml of acetic acid, and the mixture is stirred at 50° for 15 minutes. Then 0.05 ml of conc. sulfuric acid (about 1 mmol) is added, resulting in a clear yellow solution after a few minutes. After 2 hours, the solution is added dropwise to 500 ml of water, while stirring and cooling in ice, and the precipitate is filtered off and thoroughly washed with water. The moist material is dissolved in ethyl acetate, the aqueous phase is separated off, and the organic phase is washed once with a saturated aqueous sodium chloride solution, dried over sodium sulfate and concentrated under reduced pressure to 20 g. Z-Gln(Trt)-OH is crystallized by addition of hexane in portions, m.p. 161°-162°.

Provenance & Evidence