potassium carbonate; triphenylphosphine; 5,7-diphenyl-3-iodopyrazolo[1,5-a]pyrimidine; palladium on activated charcoal; copper(l) iodide in ethylene glycol dimethyl ether T=80°C; 24 h;

sodium hydroxide in water; toluene T=90°C; 1 h; Product distribution / selectivity;

1: With bis-triphenylphosphine-palladium(II) chloride; copper(l) iodide; triethylamine in tetrahydrofuran T=20°C; Sonogashira coupling; 1 h; 2: With potassium fluoride; oxygen in tetrahydrofuran; methanol T=20°C; Glaser coupling; 24 h;

iron; acetic acid T=60 - 70°C; 0.583333 h;

1: 97 percent / Cu(OAc)2*H2O, pyridine / methanol / 3.5 h 2: Fe, HOAc / 0.58 h / 60 - 70 °C View Scheme