Sulfuric Acid → 5,6-difluoro-2,3-dihydro-1H-indole-2,3-dione
Reaction equation
[F:1][C:2]1[CH:3]=[C:4]([NH:9][C:10](=[O:14])[CH:11]=NO)[CH:5]=[CH:6][C:7]=1[F:8].S(=O)(=O)(O)[OH:16]>>[F:8][C:7]1[CH:6]=[C:5]2[C:4](=[CH:3][C:2]=1[F:1])[NH:9][C:10](=[O:14])[C:11]2=[O:16]Participants
3
Conditions
- Temperature
- 80 °C
Procedure
A 24.5 g portion of N-(3,4-difluorophenyl)-2-(hydroxyimino)acetamide was added portionwise with stirring to 95 ml of concentrated sulfuric acid with the temperature kept between 60° and 70° C. The temperature of the reaction mixture was then raised to 80° C. for 20 minutes followed by cooling to room temperature. The mixture was then poured onto crushed ice and the resulting solid collected, giving 21.3 g of the desired compound as brick red crystals, mp 218°-220° C.
Workup
- customkept between 60° and 70° C
- temperatureby cooling to room temperature
- additionThe mixture was then poured
- customonto crushed ice
- customthe resulting solid collected
Sources & evidence
- ORD record
- ord-59179b2e945643bea873e1c3bc20fb5d
- Source dataset
- uspto-grants-1989_05
- Patent number
- US04833270
Reaction notes
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