potassium hydroxide in dimethyl sulfoxide T=80°C; 16 h;

1: thiophene-2-carbaldehyde With ammonia; iodine in tetrahydrofuran; water T=20°C; 1 h; 2: 1-cyano-guanidine With potassium hydroxide in tetrahydrofuran; water 24 h; Heating; Further stages.;

1: aq. NH3; iodine / tetrahydrofuran / 1 h / 25 °C 2: tetrahydrofuran; H2O / 80 °C / microwave irradiation View Scheme