1: 4,6-dichloropyrimidine-2-(methylthio)pyrimidine With lithium diisopropyl amide in tetrahydrofuran; n-heptane; chlorobenzene T=-78°C; 2.5 h; 2: methyl chloroformate in tetrahydrofuran; n-heptane; chlorobenzene T=-78 - 25°C; 0.5 h;

potassium carbonate in N,N-dimethyl-formamide T=0 - 20°C; 2.5 h;