[NH2:1][C:2]1[CH:3]=[C:4]([CH:9]=[CH:10][N:11]=1)[C:5]([O:7][CH3:8])=[O:6].[CH3:12][N:13](C(OC)OC)C.CO>CN(C=O)C>[CH3:8][O:7][C:5]([C:4]1[CH:9]=[CH:10][N:11]2[N:13]=[CH:12][N:1]=[C:2]2[CH:3]=1)=[O:6]To a solution of methyl 2-aminoisonicotinate (28.8 g, 191 mmol) in DMF (97.5 mL) was added DMF-DMA (70.6 mL, 496 mmol) and the mixture heated to 130° C. for 12 hours. The mixture was then concentrated to give a residue. To the residue was added MeOH (381 mL), followed by NH2OHSO4 (31.9 g, 248 mmol) and the resulting mixture was stirred at room temperature overnight. The reaction mixture was concentrated to give methyl[1,2,4]triazolo[1,5-a]pyridine-7-carboxylate in 18% yield, 6 g. To a solution of methyl[1,2,4]triazolo[1,5-a]pyridine-7-carboxylate (3 g, 16 mmol) in methanol was added 1M aq. LiOH (70 mL) and the resulting mixture stirred for 10 hours at room temperature. The pH was adjusted to 5-6 using aq. HCl and the whole mixture extracted with EtOAc (30 mL×3). The combined organic layers were dried (Na2SO4) and concentrated in vacuo to give the title compound as a white solid in 38% yield, 1.05 g 1H NMR (400 MHz, DMSO-d6) δ: 7.56-7.58 (m, 1H), 8.32 (m, 1H), 8.66 (m, 1H), 9.04-9.06 (m, 1H), 13.5-14.0 (s, 1H).
Wird geladen…
