122181-85-5

77287-34-4

159326-71-3

Step 2: Synthesis of pyrrolo[2,1-f][1,2,4]triazin-4(3H)-one; Methyl 1-amino-1H-pyrrole-2-carboxylate (7.5 g, 53.5 mmol) was dissolved in formamide (30 mL). The reaction mixture was first heated at 170 °C for 1 h, and then warmed to 190 °C to continue the reaction for 2 h. The reaction was completed by cooling the mixture for 1 h. The reaction was then continued for 2 h. After completion of the reaction, the mixture was cooled to room temperature. The resulting solid was purified by recrystallization from ethyl acetate to afford the target product pyrrolo[2,1-f][1,2,4]triazin-4(3H)-one as a white solid (5.0 g, 37.0 mmol, 69% yield).1H NMR (400 MHz, CDCl3) δ: 7.57 (s, 1H), 7.47 (dd, J = 2.8 Hz, 1.6 Hz (s, 1H), 7.10 (dd, J = 4.4 Hz, 1.6 Hz, 1H), 7.47 (dd, J = 4.4 Hz, 2.8 Hz, 1H).