Acetic Anhydride → (1R,4S)-1-acetylamino-4-(hydroxymethyl)-2-cyclopentene

Participants

Reaction Conditions

Reaction Steps

25 g of (1R,4S)-1-amino-4-(hydroxymethyl)-2-cyclopentene hydrochloride were dissolved in 182 ml of acetic anhydride and, at 0° C., a solution of 18.25 g of triethylamine in 60 ml of acetic anhydride was added. The mixture was stirred at 80° C. for 3 h and then cooled to room temperature. The triethylamine hydrochloride was filtered off and washed with 120 ml of n-hexane. The filtrate was evaporated. The residue was mixed with 300 ml of toluene and stirred at room temperature in the presence of 5.2 g of active charcoal and 13 g of Celite for 20 min. After filtration and washing of the filter cake (3×40 ml of toluene), the solvent was completely evaporated off. The residue was mixed with 180 ml of methanol and 15.5 g of K2CO3 and stirred at room temperature for 10 h. The suspension was filtered and the filtrate was evaporated. The residue was suspended in 750 ml of isopropyl acetate and boiled in the presence of 0.5 g of active charcoal under reflux for 1.5 h. After the active charcoal filtration (70-80° C.), the filtrate was cooled at 0° C. overnight. The title compound was filtered, washed with 80 ml of cold isopropyl acetate and dried in vacuo. 17.2 g of product were obtained. The yield was 66%.

Provenance & Evidence