3-Methyl-2-butanone → 2,3,3-Trimethyl-4-carboxy-3H-indole

HRID 61512

Reaction equation

HRID 61512 reaction equation
[NH:1]([C:3]1[CH:4]=[C:5]([CH:9]=[CH:10][CH:11]=1)[C:6]([OH:8])=[O:7])N.[CH:12]([C:15]([CH3:17])=O)([CH3:14])[CH3:13]>C(O)C.S(=O)(=O)(O)O>[CH3:17][C:15]1[C:12]([CH3:14])([CH3:13])[C:4]2[C:3](=[CH:11][CH:10]=[CH:9][C:5]=2[C:6]([OH:8])=[O:7])[N:1]=1

Participants

5

Reactant 2

HCID 112513-Methyl-2-butanoneHCID 27365213-Hydrazinobenzoic acid

Product 1

HCID 665977182,3,3-Trimethyl-4-carboxy-3H-indoleYield 81.4%

Reagents, catalysts & solvents 2

HCID 702EthanolSolventHCID 1118Sulfuric AcidSolvent

Procedure

A solution of 3-hydrazinobenzoic acid (30.0 g, 197 mmol), isopropylmethylketone (31.7 mL, 296 mmol) in ethanol (500 mL) and sulfuric acid (5 mL) was heated under reflux in an oil bath for 20 h. After cooling to ambient temperature the solvent was evaporated off under reduced pressure to a small volume of ˜200 mL. Collected the solid with a filter funnel, washed with iPrOH (3×30 mL) and ethyl ether (3×30 mL) and dried. Further drying of the solid in an oven at 45° C. under high vacuum for 18 h provided 32.59 g (81.3%) of the product.

Workup

  1. temperatureunder reflux in an oil bath for 20 h
  2. customwas evaporated off under reduced pressure to a small volume of ˜200 mL
  3. customCollected the solid with a filter funnel
  4. washwashed with iPrOH (3×30 mL) and ethyl ether (3×30 mL)
  5. customdried
  6. customFurther drying of the solid in an oven at 45° C. under high vacuum for 18 h

Sources & evidence

ORD record
ord-849145d5f1b84f94ad041af0e7fe6118
Source dataset
uspto-grants-2016_09
Patent number
US09441270B2

Linked notes

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