General procedure for the synthesis of 4-iodo-1-methyl-1H-imidazole from 4,5-diiodo-1-methyl-1H-imidazole: At room temperature, EtMgBr (3.0 M ether solution, 11.00 mL, 32.9 mmol) was slowly added dropwise to 4,5-diiodo-1-methyl-1H-imidazole (10.00 g, 29.9 mmol) in anhydrous CH2Cl2 ( 150 mL) solution for more than 15 minutes dropwise. The reaction mixture was then stirred for 20 minutes. After confirming complete consumption of the feedstock by TLC monitoring, the reaction was quenched by adding water (20 mL) to the reaction mixture. The organic and aqueous layers were separated and the aqueous layer was extracted with CH2Cl2 (3 x 50 mL). All organic layers were combined, dried with anhydrous Na2SO4 and concentrated under reduced pressure to afford 4-iodo-1-methylimidazole (15) as a light brown oil (5.86 g, 94% yield).
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