1: 3-amino-4-cyano-5-methylsulfanylthiophene-2-carboxylic acid ethyl ester With sodium sulfide in N,N-dimethyl-formamide T=50°C; 1 h; 2: chloroacetonitrile With potassium carbonate in N,N-dimethyl-formamide T=50°C; 6 h;

tetrabutylammomium bromide; potassium carbonate 1.) benzene, 2.) 60 deg C, 4 h; Yield given. Multistep reaction;