Sulfuric Acid → 5-carbamoyl-4-(4-nitrophenyl)-1H-pyrrole-3-carboxylic acid
Reaktionsgleichung
[C:1]([C:4]1[NH:8][CH:7]=[C:6]([C:9]([O:11]CC)=[O:10])[C:5]=1[C:14]1[CH:19]=[CH:18][C:17]([N+:20]([O-:22])=[O:21])=[CH:16][CH:15]=1)(=[O:3])[NH2:2].S(=O)(=O)(O)O>>[C:1]([C:4]1[NH:8][CH:7]=[C:6]([C:9]([OH:11])=[O:10])[C:5]=1[C:14]1[CH:15]=[CH:16][C:17]([N+:20]([O-:22])=[O:21])=[CH:18][CH:19]=1)(=[O:3])[NH2:2]Komponenten
3
Versuchsvorschrift
A solution of 2.8 g (9.232 mmol) of ethyl 5-carbamoyl-4-(4-nitrophenyl)-1H-pyrrole-3-carboxylate in 33.6 cm3 (0.614 mol) of concentrated sulfuric acid is heated at a temperature in the region of 80° C. for 2 hours. The reaction mixture is poured slowly and with stirring into 350 cm3 of ice-water. After stirring for 30 minutes, the reaction mixture is filtered through a No 3 sinter funnel. The solid is washed with 4 times 100 cm3 of ice-water and then dried under reduced pressure (2.7 kPa) at a temperature in the region of 45° C. for 24 hours, to give 2.25 g of 5-carbamoyl-4-(4-nitrophenyl)-1H-pyrrole-3-carboxylic acid in the form of a beige-coloured solid; ES+: m/z=276: [M+H]+; ES−: m/z=274: [M−H]−.