73781-74-5

42137-24-6

73781-74-5

Step 3 Synthesis of 4-aminothiophene-2-carbonitrile (3): 4-nitrothiophene-2-carbonitrile (2) (100 mg, 0.65 mmol) was dissolved in ethyl acetate (4 mL) and dioxane (0.2 mL) and 5% Pd/C catalyst (77 mg) was added. After 16 h of reaction under hydrogen atmosphere, 10% Pd/C Degussa wet catalyst (30 mg) was added and stirring was continued for 24 h under hydrogen at 1 atmosphere. Upon completion of the reaction, the catalyst was removed by diatomaceous earth filtration and the filtrate was concentrated under vacuum. The product was purified by column chromatography using 20-30% ethyl acetate/hexane as eluent to give 4-aminothiophene-2-carbonitrile (3).LRMS (ESI) Calculated value: 124.2, Measured value: 125.1 (MH)+.