1: 4-oxo-2-thioxo thiazolidine With bromo-Wang resin; N-ethyl-N,N-diisopropylamine in N,N-dimethyl-formamide T=20°C; 40 h; 2: piperidine in ethylene glycol dimethyl ether; 2,2,2-trifluoroethanol T=70°C; 3 h;

T=90°C; 2 h;

triethylamine