5-Methyl-4-nitro-thiophene-2-carboxylic acid 1,3-benzodioxol-5-ylmethyl ester → 5-Methyl-4-amino-thiophene-2-carboxylic acid 1,3-benzodioxol-5-ylmethyl ester

Participants

Reaction Steps

Sponge nickel (0.5 g water wet) was added to a solution of 5-methyl-4-nitro-thiophene-2-carboxylic acid 1,3-benzodioxol-5-ylmethyl ester (0.55 g, 1.7 mmol) from Step 1 in tetrahydrofuran (100 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 2.79 hours, the pressure was released, and the mixture was filtered. The slurry was washed with tetrahydrofuran, and the filtrate was stripped of solvent under reduced pressure to afford a crystalline residue. The residue was triturated in diethyl ether and filtered to afford 5-methyl-4-amino-thiophene-2-carboxylic acid 1,3-benzodioxol-5-ylmethyl ester. Chromatography on silica gel in ethyl acetate, then evaporation of the effluent under reduced pressure gave 0.14 g of 5-methyl-4-amino-thiophene-2-carboxylic acid 1,3-benzodioxol-5-ylmethyl ester.

Provenance & Evidence