Acetic Anhydride → 1H-Indazole-4-carboxylic acid, 1-acetyl-6-bromo-, methyl ester

HRID 1854103Notes

Reaction equation

HRID 1854103 reaction equation
[NH2:1][C:2]1[C:3]([CH3:13])=[C:4]([CH:9]=[C:10]([Br:12])[CH:11]=1)[C:5]([O:7][CH3:8])=[O:6].[C:14]([O-:17])(=O)[CH3:15].[K+].C(OC(=O)C)(=O)C.[N:26](OC(C)(C)C)=O.C1OCCOCCOCCOCCOCCOC1>C(Cl)(Cl)Cl>[C:14]([N:1]1[C:2]2[CH:11]=[C:10]([Br:12])[CH:9]=[C:4]([C:5]([O:7][CH3:8])=[O:6])[C:3]=2[CH:13]=[N:26]1)(=[O:17])[CH3:15]

Participants

7

Reactant 5

HCID 7918Acetic AnhydrideHCID 10906Tert-Butyl nitriteHCID 2855718-Crown-6HCID 517044Potassium AcetateHCID 24729181Methyl 3-Amino-5-bromo-2-methylbenzoate

Product 1

HCID 682954331H-Indazole-4-carboxylic acid, 1-acetyl-6-bromo-, methyl esterYield 98.5%

Reagents, catalysts & solvents 1

HCID 6212ChloroformSolvent2×

Procedure

To a stirred solution of methyl 3-amino-5-bromo-2-methylbenzoate (15 g, 61.5 mmol) in chloroform (150 mL), was added potassium acetate (6.32 g, 64.4 mmol) and acetic anhydride (12.6 g, 122.9 mmol) and reaction mixture was stirred at room temperature for 12 h. After this time, tert-butyl nitrite (25.3 g, 246.1 mmol) and 18-crown-6 (5.7 g, 21.5 mmol) were added and reaction stirred again at 65° C. for 3 h. On completion, the reaction mass was cooled to room temperature, diluted with chloroform (500 mL) and washed with sat. sodium bicarbonate solution. The organic layer was dried over sodium sulfate and concentrated to afford the title compound (18 g, 98.3%).

Workup

  1. customreaction
  2. stirringstirred again at 65° C. for 3 h
  3. temperatureOn completion, the reaction mass was cooled to room temperature
  4. washwashed with sat. sodium bicarbonate solution
  5. dry with materialThe organic layer was dried over sodium sulfate
  6. concentrationconcentrated

Sources & evidence

ORD record
ord-4f002414fc664016a372f82af4da6be1
Source dataset
uspto-grants-2015_02
Patent number
US08962620B2

Reaction notes

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