Methyl 5-methyl-4-nitrothiophene-2-carboxylate → Methyl 4-amino-5-methylthiophene-2-carboxylate

Participants

Reaction Steps

Sponge nickel (1.0 g water wet) was added to a solution of 5-methyl-4-nitro-thiophene-2-carboxylic acid methyl ester (1.79 g, 8.9 mmol) in methanol (50 mL), and the mixture was hydrogenated at room temperature under a hydrogen atmosphere at a starting pressure of 50 psi. After a reaction time of 25 hours, the pressure was released and the mixture filtered. The slurry was rinsed with methanol, and the filtrate was stripped of solvent under reduced pressure to afford 1.5 g of 5-methyl-4-amino-thiophene-2-carboxylic acid methyl ester. A sample was dissolved in ethyl acetate and filtered through a short column of silica gel. Evaporation of the effluent under reduced pressure gave product with a mp 90-91° C.

Provenance & Evidence