反应详情

温度

2.5 °C

1-methyl-4-nitro-2-pyrrolecarboxylic acid (III) (1.0 g, 6.0 mmol) is dissolved in 20 mL of a 1 M sodium carbonate aqueous solution and hydrogenated in presence of 250 mg of 10% Pd/C catalyst. When the uptake of hydrogen has stopped, the catalyst is removed by filtration and the resulting yellow solution, containing the aminoacid (VI), is slowly added to a freshly prepared benzene solution of N-formylimidazole with vigorous stirring. After the addition, the resulting two layers are stirred for additional 15 min and then the organic layer is separated and discarded. The aqueous yellow solution, cooled to 0-5° C., is carefully acidified with formic acid (pH 3.5) with vigorous stirring. The precipitated acid (V) is filtered off and washed with small portions of ice-cold water. There are obtained 0.81 g (yield 80%) of product (V): m.p. 208-210° C.; NMR (DMSO-d6), ppm: 3.85 (s, 3H); 6.75 (d, 1H); 7.35 (d, 1H); 8.15 (s, 1H).

1. customthe catalyst is removed by filtration
2. additionthe resulting yellow solution, containing the aminoacid (VI)
3. additionis slowly added to a freshly prepared benzene solution of N-formylimidazole with vigorous stirring
4. additionAfter the addition
5. customthe organic layer is separated
6. filtrationThe precipitated acid (V) is filtered off
7. washwashed with small portions of ice-cold water