Pyridine → Acibenzolar Acid Impurity 21

HRID 2106947Notes

Reaction equation

HRID 2106947 reaction equation
[S:1]1[C:5]2[C:6]([C:10]([NH2:12])=O)=[CH:7][CH:8]=[CH:9][C:4]=2[N:3]=[N:2]1.N1C=CC=CC=1.FC(F)(F)C(OC(=O)C(F)(F)F)=O>O1CCCC1>[C:10]([C:6]1[C:5]2[S:1][N:2]=[N:3][C:4]=2[CH:9]=[CH:8][CH:7]=1)#[N:12]

Participants

5

Reactant 3

HCID 1049PyridineHCID 9845Trifluoroacetic anhydrideHCID 22403364Benzo-1,2,3-thiadiazole-7-carboxylic acid amide

Product 1

HCID 22182879Acibenzolar Acid Impurity 21

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Conditions

Temperature
3 °C

Procedure

4.0 g (0.022 mol) of benzo-1,2,3-thiadiazol-7-ylcarboxylic acid amide are dissolved in 35 ml of tetrahydrofuran, and 3.6 ml (0.045 mol) of pyridine are added. The batch is then cooled to 3° C. and a solution of 3.9 ml (0.028 mol) of trifluoroacetic acid anhydride in 12 ml of tetrahydrofuran is added dropwise. The reaction mixture is subsequently stirred for 22 hours at room temperature and then poured onto ice/water and extracted twice with ethyl acetate. The extracts are washed with water, dried over magnesium sulfate and filtered through a layer of silica gel. Concentration by evaporation gives 3.5 g (99% of the theoretical yield) of crystalline product having a melting point of 119°-122° C.

Workup

  1. additionpoured onto ice/water
  2. extractionextracted twice with ethyl acetate
  3. washThe extracts are washed with water
  4. dry with materialdried over magnesium sulfate
  5. filtrationfiltered through a layer of silica gel
  6. concentrationConcentration
  7. customby evaporation
  8. customgives 3.5 g (99% of the
  9. customtheoretical yield) of crystalline product

Sources & evidence

ORD record
ord-02dd12b840fb42fbad337f0d43ed11d7
Source dataset
uspto-grants-1990_06
Patent number
US04931581

Reaction notes

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