sulfur; triethylamine in N,N-dimethyl-formamide T=50°C; 48 h;

1: anhydrous cyanoacetic acid With 4-(N,N-dimethlyamino)pyridine; poly(ethylene glycol) 3400; dicyclohexyl-carbodiimide 0.0833333 h; microwave irradiation; 2: butyraldehyde With sulfur; N-ethyl-N,N-diisopropylamine Gewald reaction; 0.333333 h; microwave irradiation; 3: methanol With potassium cyanide T=20°C;

ammonium formate T=135°C; 12 h;