Sulfuric Acid → HCID 12202680, Verbindung
Reaktionsgleichung
[C:1]([C:4]1[CH:19]=[CH:18][C:7]([O:8][C:9]2[N:17]=[CH:16][CH:15]=[CH:14][C:10]=2[C:11]([OH:13])=O)=[CH:6][CH:5]=1)([OH:3])=[O:2].S(=O)(=O)(O)O>O>[O:13]=[C:11]1[C:10]2[C:9](=[N:17][CH:16]=[CH:15][CH:14]=2)[O:8][C:7]2[CH:18]=[CH:19][C:4]([C:1]([OH:3])=[O:2])=[CH:5][C:6]1=2Komponenten
4
Edukt 2
Produkt 1
Reagenzien, Katalysatoren, Lösungsmittel 1
Versuchsvorschrift
A mixture of 2 g of 2-(p-carboxyphenoxy)nicotinic acid and 30 g of concentrated sulfuric acid is stirred at 180°-190°C for 40 minutes on an oil bath. After cooling with water, the reaction mixture is poured into ice water. A jelly-like substance produced crystallizes on heating. The crystals are filtered off, washed thoroughly with water, and recrystallized from aqueous dioxane to give 1.5 g of 5-oxo-5H-[1]benzopyrano[2,3-b]pyridine-7 -carboxylic acid melting at 293°-294°C.