p-Toluenesulfonic acid monohydrate → p-Toluenesulfonic acid

Participants

Reaction Steps

p-Toluenesulfonic acid hydrate (17.15 g, 90.16 mmol) was azeotroped with an isopropyl alcohol/toluene mixture (1:1) to provide anhydrous p-toluene sulfonic acid. The as sulfonic acid was dried under high vacuum and dissolved in a minimum of anhydrous ether. The solution of sulfonic acid was added to a solution of tert-butyl 3-benzyloxy-2-oxo-1-phenethylpropylcarbamate (17.15 g, 44.72 mmol) in a minimum of anhydrous ether under nitrogen to provide a precipitate. The mixture was stirred under nitrogen until the reaction was complete and then filtered. The precipitate was dried under vacuum to provide 3-amino-1-benzyloxy-5-phenylpentan-2-one p-toluenesulfonic acid salt (17.78 g, 38.9 mmol). 1H NMR (DMSO-d6): δ 1.84-2.01 (m, 1H), δ 2.12-2.22 (m, 1H), δ 2.28 (s, 3H), δ 2.59-2.70 (m, 2H), δ 4.24-4.35 (m, 1H), δ 4.4 (d, 2H), δ 4.5-4.6 (m, 2H), δ 7.09-7.50 (m, 14H), δ 8.15-8.35 (s, 3H).

Provenance & Evidence