反应详情

温度

0 °C

114.4 g of 2(S)-acetamido-3(S)-methoxycarbonyl-4(R)-pentanolide are heated at 120° C. for 24 hours in semi-concentrated hydrochloric acid. The solution is slowly cooled to 0° C., and the precipitate is filtered off, washed with ethyl acetate, dried under a high vacuum and recrystallised from methanol. Hydrochloride of the title compound, [α]D20 =-21.5° (1% in H2O), m.p. >250° C. The free title compound is obtained by treating the hydrochloride with an excess of propylene oxide in hot methanol, [α]D20 =-23.1° (1% in 1N HCl), m.p. 196°-200° C.

1. filtrationthe precipitate is filtered off
2. washwashed with ethyl acetate
3. customdried under a high vacuum
4. customrecrystallised from methanol. Hydrochloride of the title compound, [α]D20 =-21.5° (1% in H2O), m.p. >250° C