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

Participants

Reaction Conditions

Reaction Steps

A mixture of 4-(5-methylthiophen-2-yl)-1-trityl-1H-imidazole (2.20 g, 5.42 mmol) in THF (100 mL) was cooled to −78° C. nBuLi mL of a 1.6 M solution in hexanes, 6.2 mmol) was added dropwise (˜2 min) and the pale yellow solution was allowed to warm to −50° 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 ˜4 h) and stirred overnight. Saturated aqueous NH4Cl (2 mL) was added and the mixture was concentrated to ˜10 mL. The mixture was diluted with EtOAc, H2O, saturated aqueous Na2S2O3 and the organic phase was separated. The aqueous phase was re-extracted (EtOAc) 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 5:95 then 15:85) to give 2-iodo-4-(5-methylthiophen-2-yl)-1-trityl-1H-imidazole 2 (1.72 g, 60%) as a colourless solid. 1H NMR (CDCl3, 400 MHz) δ2.45 (s, 3H), 6.60-6.64 (m, 1H), 6.94 (s, 1H), 6.99 (d, J=3.5 Hz, 1H), 7.19-7.39 (m, 15H); 13C NMR (CDCl3, 100 MHz) δ15.3, 90.6, 120.4, 122.3, 125.5, 125.6, 127.2, 128.1, 130.8, 134.2, 138.1, 138.2, 141.4, 146.8; HRMS (EI) m/z 532.0459 C27H21N2IS [M]+. requires 532.0465.

Provenance & Evidence