Iodine → 4-(4-Iodo-3-nitrophenyl)-1-methyl-1H-pyrazole

Participants

Reaction Steps

Iodine (3.5 g, 14 mmol), acetonitrile (40 ml), and test-butyl nitrite (0.82 mL, 6.9 mmol) were combined under N2 in a 3-neck round bottom flask fitted with reflux condenser and an addition funnel. The mixture was stirred at rt. To the addition funnel was added a solution of 4-(1-methyl-1H-pyrazol-4-yl)-2-nitroaniline (1.0 g, 4.6 mmol) dissolved in DCM (20 mL) and DMSO (2 mL). This solution was added dropwise to flask at rt. The reaction was placed in a 60° C. oil bath and after 5-10 minutes bubbles began appearing. The reaction was stirred for an additional 2 h at 60° C. and then the heat was turned off and the reaction stirred at rt overnight. Aqueous sodium sulfite solution was added and the mixture was extracted with EtOAc (3×). Combined organic layers were dried over anhydrous MgSO4, filtered, concentrated onto silica gel and purified by flash chromatography using 20-60% EtOAc/hexanes. 1.43 g (95%) of 4-(4-iodo-3-nitrophenyl)-1-methyl-1H-pyrazole was isolated as a yellow solid. MS (ESI): 330, 331 [M+H]+.

Provenance & Evidence