Selenium Dioxide → 6-chloro-3-iodo-1-trityl-1H-pyrazolo[4,3-c]pyridine-4-carbaldehyde

Participants

Reaction Conditions

Reaction Steps

6-Chloro-3-iodo-4-methyl-1-trityl-1H-pyrazolo[4,3-c]pyridine (20 g, 37.3 mmol) was dissolved in dioxane (400 mL) and selenium dioxide (12.43 g, 112 mmol) was added. The reaction mixture was stirred at 100° C. for 6 hrs. Selenium dioxide (4.14 g, 37.3 mmol) was added and the reaction mixture continued stirring at 100° C. overnight. The reaction was filtered over celite, rinsed with DCM, and concentrated in vacuo. The residue was dissolved in DCM (1.0 L) and filtered over celite. The material was concentrated in vacuo while loading on silica gel. Purification by flash chromatography (0-5% DCM/EtOAc) gave 6-chloro-3-iodo-1-trityl-1H-pyrazolo[4,3-c]pyridine-4-carbaldehyde (10.88 g, 19.79 mmol, 53.0%). 1H NMR (ppm, 500 MHz, DMSO-d6) δ 10.54 (s, 1H), 7.39-7.35 (m, 10H), 7.17-7.11 (m, 5H), 6.29 (s, 1H).

Provenance & Evidence