A stirred suspension of 4-chloro-5-nitro-1-(phenyl sulfonyl)-1H-pyrrolo[2,3-b]pyridine (11.10 g, 33.0 mmol) in isopropanol (IPA) (100 ml) was treated with tetrahydro-2H-pyran-3-amine hydrochloride (5.0 g, 36.0 mmol) and N,N-diisopropylethylamine (15.0 mL, 84.0 mmol), and stirred at 82° C. for four hours. The mixture was then cooled and left to stand at 5° C. for 2 h. The resulting precipitate was collected by filtration and washed with IPA. Trituration (water) afforded 11.7 g (89%) of 5-nitro-1-(phenylsulfonyl)-N-(tetrahydro-2H-pyran-3-yl)-1H-pyrrolo[2,3-b]pyridin-4-amine. LCMS (Method E, ESI): RT=1.65 min, m+H=403.2; 1H NMR (400 MHz, CDCl3) δ 9.22 (d, J=7.6 Hz, 1H), 9.11 (s, 1H), 8.20 (d, J=8.0 Hz, 2H), 7.69-7.56 (m, 2H), 7.60-7.42 (m, 2H), 6.76 (d, J=4.2 Hz, 1H), 4.14 (ddt, J=10.7, 7.1, 3.5 Hz, 1H), 3.98 (dd, J=11.5, 2.7 Hz, 1H), 3.85-3.62 (m, 2H), 3.58 (dd, J=11.5, 6.4 Hz, 1H), 2.27-2.06 (m, 1H), 1.86 (tdt, J=11.8, 7.5, 3.9 Hz, 2H), 1.79-1.63 (m, 1H).
