反应详情

Ethyl chloroformate (1.19 mL, 12.4 mmol) in MeCN (5 mL) was added dropwise to a 1.00 g (6.21 mmol) of 5-bromo-1-methyl-1H-imidazole (Aldrich) in 30 mL of MeCN under N2. The mixture was stirred and allowed to warm to rt overnight. The mixture was concentrated and the residue was treated with 2M NaOH (100 mL) and extratcted with CH2Cl2 (3×100 mL). The combined extracts were washed with brine, dried with MgSO4, filtered, concentrated, and chromatographed (0-50% EtOAc in hexanes) to give the 5-bromo-1-methyl-1H-imidazole-2-carboxylic acid ethyl ester as a yellow oil (800 mg).

1. concentrationThe mixture was concentrated
2. additionthe residue was treated with 2M NaOH (100 mL)
3. washThe combined extracts were washed with brine
4. dry with materialdried with MgSO4
5. filtrationfiltered
6. concentrationconcentrated
7. customchromatographed (0-50% EtOAc in hexanes)