Triphosgene → 7-bromo-8-iodo-[1,2,4]triazolo[4,3-a]pyridin-3(2H)-one

Participants

Reaction Conditions

Reaction Steps

To a solution of triphosgene (91.7 g, 309 mmol) in THF (800 mL) was added 4-bromo-2-hydrazinyl-3-iodopyridine (32.3 g, 103 mmol) in several portions over 1 h at 20° C. The resulting reaction mixture was stirred for an additional 2 h at 20° C. The reaction was monitored by HPLC (acetonitrile-water-TFA) and completed in 2 h. The reaction mixture was cooled in ice bath and quenched by careful addition of H2O (800 mL). A large amount of solid was precipitated. This was filtered and successively washed with H2O (2×100 mL) and Et2O (100 mL). The filtrate was concentrated in vacuo to reduce volume by 50%. Newly formed solid was then filtered. This 2nd crop was also washed with H2O and Et2O. The two crops were combined and dried under high vacuum to obtain the title compound as a light beige solid (34 g, 100 mmol). MS: [M+H]+=337.9. 1H NMR (400 MHz, DMSO) δ 6.76 (d, J=7.03 Hz, 1H), 7.78 (d, J=7.47 Hz, 1H), 12.68 (s, 1H).

Provenance & Evidence