Reaction #2298613

Reaction equation

acetic anhydride

methyl 3-amino-4-methyl-2-thiophenecarboxylic acid methyl ester

→

3-(formylamino)-4-methyl-2-thiophenecarboxylic acid methyl ester

Yield 95.0%

Solvents

Formic acid

Conditions

Workup

1. 1
   Temperaturewhile cooling in an ice bath
2. 2
   OtherThe cooling bath was removed
3. 3
   workup.ADDITIONThe reaction mixture was diluted with water (100 mL)
4. 4
   Filtrationthe solid product collected by vacuum filtration

Procedure

Formic acid (53 mL) was added to acetic anhydride (53 mL) while cooling in an ice bath. Solid methyl 3-amino-4-methyl-2-thiophenecarboxylic acid methyl ester (1, 18.2 g, 0.11 mol) was added to the cold solution in small portions. The cooling bath was removed and the resulting suspension was stirred at room temperature for 4 hours. The reaction mixture was diluted with water (100 mL) and the solid product collected by vacuum filtration to yield 3-(formylamino)-4-methyl-2-thiophenecarboxylic acid methyl ester (20.2 g, 95% yield) as a white solid.

Source