To a solution of 1,1-dimethylethyl 3-bromo-5,6-dihydro[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-carboxylate (200 mg, 0.660 mmol, commercially available) in 1,4-dioxane (2 mL), 2-(tributylstannanyl)pyridine (364 mg, 0.990 mmol) was added and mixture was degassed with a stream of argon for few minutes. Pd(Ph3P)4 (38.1 mg, 0.033 mmol) was then added followed by copper(I) iodide (39.2 mg, 0.206 mmol) and the mixture was submitted to microwave irradiation heating at 130° C. for 25 minutes until the reaction was complete by LCMS. Volatiles were removed under reduced pressure and the residue was purified by chromatography on silica gel (Snap 11 g NH column) eluting with a gradient from 0 to 100% ethyl acetate in iso-hexane (10CV) and then with 100% ethyl acetate (7CV). A colourless oil was obtained. The product was still impure and so was further purified by chromatography on silica gel (Si 5 g) eluting with a 80% ethyl acetate in iso hexane (5CV) and then with 10% MeOH in DCM (5 CV) then by chromatography on silica gel (Si column 5 g) eluting first with ethyl acetate (4CV) and then with 10% MeOH in DCM (6CV). Colourless oil was obtained of the desired product in 115 mg.
