Réaction #64363

Équation de réaction

sulfuric acid

4-cyano-2,2-dimethyl-6-nitro-2H-1-benzopyran

acetic acid

sulfuric acid

→

2,2-dimethyl-6-nitro-2H-1-benzopyran-4-carboxylic acid

Solvants

water

Conditions de réaction

Traitement

1. 1
   Températurewas heated
2. 2
   Températureat reflux for 1.5 hours
3. 3
   LavageThe thus precipitated crystal was washed with water
4. 4
   Autredried
5. 5
   Autrerecrystallized from a mixed solvent of acetonitrile and water

Mode opératoire

MS: 230 (M+) ##STR41## A mixture of 13.0 g of 4-cyano-2,2-dimethyl-6-nitro-2H-1-benzopyran, 400 ml of acetic acid, 200 ml of water, and 100 ml of concentrated sulfuric acid was heated at reflux for 1.5 hours. After adding 100 ml of concentrated sulfuric acid, the refluxing was further continued for an additional period of 1 hour. The reaction mixture was poured into ice-water. The thus precipitated crystal was washed with water, dried, and recrystallized from a mixed solvent of acetonitrile and water to obtain 11.9 g of 2,2-dimethyl-6-nitro-2H-1-benzopyran-4-carboxylic acid represented by formula shown below.

Source