New and Practical Synthesis of Momelotinib

New and practical synthetic route of momelotinib, a JAK inhibitor, is described on a decagram scale. A convergent synthetic process is adopted to prepare the methyl 4‐(2‐((4‐morpholinophenyl)amino)pyrimidin‐4‐yl) benzoate intermediate, by cyclization of 1‐(4‐morpholinophenyl)guanidine and methyl 4‐(3‐(dimethylamino)acryloyl)benzoate in high yield and mild conditions. Momelotinib is obtained in 43.2% yield over five steps and 99.1% purity (HPLC).