Reaktion #11030

Reaktionsgleichung

chlorosulfonic acid

2-(2-nitrophenoxy)fumaric acid

2-(2-nitrophenoxy)maleic acid

→

8-nitro-2-carboxy-4-oxo-4H-1-benzopyran

Ausbeute 70.0%

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeAfter a reaction container equipped with a stirrer, a cooling tube
2. 2
   workup.ADDITIONwas added
3. 3
   Sonstigeto obtain a reaction solution

Vorschrift

After a reaction container equipped with a stirrer, a cooling tube and a thermometer was charged with 25 parts by weight of chlorosulfonic acid, 5 parts by weight of a mixture (content: 65.7% by weight) containing 2-(2-nitrophenoxy)fumaric acid and 2-(2-nitrophenoxy)maleic acid was added. After that, the inner temperature was raised to 60° C. and the mixture was stirred and kept at the same temperature for 6 hours to obtain a reaction solution containing 8-nitro-2-carboxy-4-oxo-4H-1-benzopyran (reaction yield: 70%). After cooled to room temperature, the reaction solution was gradually added into 50 parts by weight of water and the mixture was gradually cooled to an inner temperature of 0° C. Precipitated crystals were filtered and dried to obtain 2.2 parts by weight of 8-nitro-2-carboxy-4-oxo-4H-1-benzopyran as crystals (content: 96.9% by weight, yield: 65%).

Quelle