Reaction #89790

Reaction equation

3-hydrazinobenzoic acid

isopropylmethylketone

→

product

Yield 81.4%

2,3,3-Trimethyl-4-carboxy-3H-indole

Yield 81.4%

Solvents

ethanol

sulfuric acid

Conditions

Workup

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

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.

Source