A solution of DMF/H2O (4:1) was de-gassed for 15 min. DMF/H2O (4:1, 6 ml) and 1-vinyloxy-butane (0.59 ml, 4.53 mmol) were added to a mixture of Pd(OAc)2 (6 mg, 26 μmol), 1,3-bis(diphenylphosphino)propane (24 mg, 57 K2CO3 (150 mg, 1.01 mmol), 12-bromo-5H-6-thia-4,5-diaza-chrysene 6,6-dioxide 545 (370 mg, 0.91 mmol), under nitrogen. The mixture was heated at 90° C. for 2.5 h in the microwave. After cooling, the reaction was diluted with THF (2 ml) and 1M HCl (2 ml) and the mixture was stirred for 18 h. The mixture was further diluted with EtOAc (10 ml) and washed with water (10 ml, ×3). The precipitate formed during work-up was collected by filtration of the organic and aqueous phases and was found to be the title compound (140 mg, 40%). The organic phase was dried (Na2SO4) and concentrated in vacuo. The residue was triturated from MeOH to give the title compound (90 mg, 24%) which was used in the next step without further purification.
