1: 5-(5-bromo-2-ethoxyphenyl)-1-methyl-3-n-propyl-1,6-dihydro-7H-pyrazolo[4,3-d]-pyrimidin-7-one With 1,10-phenanthroline; K2S2O5; tetraethylammonium bromide; sodium formate; palladium diacetate; triphenylphosphine in dimethyl sulfoxide T=70°C; 3 h; Inert atmosphereMicrowave irradiation; 2: With N-chloro-succinimide in tetrahydrofuran T=23°C; 1.5 h; Inert atmosphere; 3: piperidine With N-ethyl-N,N-diisopropylamine in tetrahydrofuran T=23°C; 20 h; Inert atmosphere; chemoselective reaction;

1.1: potassium bromide; Oxonereg; / water; acetone / 2 h / 23 °C 2.1: K2S2O5; sodium formate; palladium diacetate; triphenylphosphine; 1,10-phenanthroline; tetraethylammonium bromide / dimethyl sulfoxide / 3 h / 70 °C / |Inert atmosphere; |Microwave irradiation 2.2: 1.5 h / 23 °C / |Inert atmosphere 2.3: 20 h / 23 °C / |Inert atmosphere View Scheme