1: 5-bromo-thiophene-2-carboxylic acid With methyl-magnesium chloride; lithium chloride in tetrahydrofuran T=-20°C; 0.333333 h; 2: With isopropylmagnesium chloride lithium chloride complex in tetrahydrofuran T=20°C; 0.5 h; 3: methanethiosulfonic acid S-methyl ester in tetrahydrofuran T=-20 - 20°C; Further stages.;

n-butyllithium; diethyl ether anschliessend Behandeln mit festem Kohlendioxid;

potassium hydroxide

dihydrogen peroxide; acetic acid