The procedure used for the preparation of the first step of intermediate M was used to prepare 4-Amino-5-(4-nitro-phenyl)-pyrrolo[2,1-f][1,2,4]triazine-6-carboxylic acid (2,2-dimethoxy-ethyl)-amideby substituting 2,2-Dimethoxy-ethylamine for 2,2,2-trifluoro-ethylamine hydrochloride salt. To a solution of methanesulfonic acid (1.5 ml) was added P2O5 (225.0 mg, 1.58 mmol) followed by the addition of 4-amino-5-(4-nitro-phenyl)-pyrrolo[2,1-f][1,2,4]triazine-6-carboxylic acid (2,2-dimethoxy-ethyl)-amide (150 mg, 0.388 mmol). The dark brown mixture was heated to 100° C. and allowed to stir for 18 hrs. The mixture was then poured over ice (15 g), stirred for fifteen minutes and enough saturated sodium carbonate solution was added to neutralize the reaction. A white precipitate was filtered and collected (35 mg, 27%). 1H-NMR (DMSO-d6)δ 8.33 (s, 1H), 8.31 (m, 2H), 8.03 (d, J=10 Hz, 2H), 7.73 (d, J=10 Hz, 2H), 7.28 (s, 1H). MS [M+H]+=323.2; LCMS RT=2.51 min.
