Iodine → 2-Iodo-1-methyl-4-(5-methylthiophen-2-yl)-1H-imidazole

Participants

Reaction Conditions

Reaction Steps

A mixture of 1-methyl-4-(5-methylthiophen-2-yl)-1H-imidazole 5 (2.36 g, 13.3 mmol) in THF (0.100 mL) was cooled −78° C. nBuLi (9.53 mL of a 1.6 M solution in hexanes, 15.2 mmol) was added dropwise (˜2 min) and the pale yellow solution was allowed to warm to −40° C. (over ˜1 h) and then re-cooled to −78° C. I2 (2.74 g, 10.4 mmol) was added and the mixture was allowed to warm to room temperature (over ˜2 h) and stirred overnight. Saturated aqueous NH4Cl (2 mL) was added and the mixture was concentrated to ˜10 mL. The mixture was diluted with CH2Cl2. H2O, saturated aqueous Na2S2O3 and the organic phase was separated. The aqueous phase was re-extracted (CH2Cl2) and the combined organics were washed (saturated aqueous NaCl), dried (MgSO4), filtered and concentrated to give a residue. The residue was purified by flash chromatography (EtOAc/hexanes 10:90 then 15:85 then 25:75) to give 2-iodo-1-methyl-4-(5-methylthiophen-2-yl)-1H-imidazole 6 (3.37 g, 84%) as a colourless solid. 1H NMR (CDCl3, 400 MHz) δ2.46 (d, J=0.8 Hz, 3H), 3.59 (s, 3H), 6.62-6.66 (m, 1H), 7.04 (d, J=3.5 Hz, 1H), 7.11 (s, 1H); 13C NMR (CDCl3, 100 MHz) δ15.3, 36.8, 91.0, 118.7, 122.2, 125.5, 134.3, 138.1, 140.5; HRMS (EI) m/z 303.9533 C9H9N21S [M]+. requires 303.9526.

Provenance & Evidence