1: 3,7-dimethyl xanthine With sodium hydride in dimethyl sulfoxide T=60°C; 0.333333 h; Inert atmosphere; 2: 4-chloro-butyric acid ethyl ester in dimethyl sulfoxide T=60°C; Inert atmosphere;

potassium carbonate in N,N-dimethyl-formamide T=75°C;

hydrogenchloride 1 h; Heating;