To a solution of 4,6-dichloro-5-(2-methoxy-phenoxy)-[2,2′]bipyrimidinyl (prepared as described in [6] and [11]) (1.74 g) in DMSO (5 ml) was added n-propanesulfonamide potassium salt (1.77 g). Stirring was continued for 10 days at rt. The reaction mixture was poured onto ice/water and acidified by 2N HCl. The precipitate was filtered off, washed with water and dried at HV to give n-propanesulfonic acid [6-chloro-5-(2-methoxy-phenoxy)-[2,2′]bipyrimidinyl-4-yl]-amide (2.17 g) as a white powder. LC-MS: tR: 4.14, [M+H]+: 434.13.
