Sulfuric Acid → 2-Amino-3,6-difluorobenzamide

HRID 2386920Notes

Reaction equation

HRID 2386920 reaction equation
[NH2:1][C:2]1[C:9]([F:10])=[CH:8][CH:7]=[C:6]([F:11])[C:3]=1[C:4]#[N:5].S(=O)(=O)(O)[OH:13].[NH4+].[OH-]>O>[NH2:1][C:2]1[C:9]([F:10])=[CH:8][CH:7]=[C:6]([F:11])[C:3]=1[C:4]([NH2:5])=[O:13]

Participants

5

Reactant 3

HCID 1118Sulfuric AcidHCID 14923Ammonium Hydroxide2×HCID 450905912-Amino-3,6-difluorobenzonitrile

Product 1

HCID 592230322-Amino-3,6-difluorobenzamide

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Conditions

Temperature
70 °C

Procedure

2-Amino-3,6-difluorobenzonitrile (2.3 g, 15 mmol) was added to concentrated sulfuric acid (5 mL) in a 25 mL 2-necked flask equipped with a thermometer with good stirring. The temperature rose to around 40° C. and the mixture became homogeneous. The solution was heated to 70° C. for 2 hours, cooled to room temperature, poured over ice, neutralized with concentrated NH4OH using water and NH4OH to rinse the flask and adding ice as necessary to keep the mixture cold. The separated solid was collected by filtration, washed with water and dried to give 2-amino-3,6-difluorobenzamide, 2.2 g. A second crop of 0.24 g was collected from the cold, concentrated filtrate, 95% overall. M.P. 121-123° C., LC/MS (ESI) m/z 172, 1H NMR (300 MHz, d6-DMSO) δ 7.70 (bs, 1H), 7.63 (bs, 1H), 7.10 (m, 1H), 6.32 (m, 1H), 6.05 (bs, 2H).

Workup

  1. customequipped with a thermometer with good stirring
  2. customrose to around 40° C.
  3. temperaturecooled to room temperature
  4. washto rinse the flask
  5. additionadding ice as necessary
  6. filtrationThe separated solid was collected by filtration
  7. washwashed with water
  8. customdried

Sources & evidence

ORD record
ord-d600396a034249d283e248f1d654a9b9
Source dataset
uspto-grants-2012_09
Patent number
US08268843B2

Reaction notes

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