2-Methylbenzenesulfonic acid hydrate → (R)-2-acetamido-3-ethoxycarbonyl-2-penten-4-olide

Participants

Reaction Conditions

Reaction Steps

12.04 g of (R)-2-amino-3-ethoxycarbonyl-2-penten-4-olide are dissolved in 48 ml of acetic anhydride, 125 mg of toluenesulphonic acid monohydrate are added and the whole is stirred overnight at 40° C. The mixture is concentrated by evaporation, dissolved in ethyl acetate and washed with water. The ethyl acetate is distilled off and the residue is recrystallised from ethyl acetate/cyclohexane, [α]D20 =+62.3° (3% in CHCl3), m.p. 119°-122° C.

Provenance & Evidence