Potassium Carbonate → 1-(4-Benzyloxyphenyl)-2-(2,4-dichlorophenyl)-5-methyl-1H-imidazole-4-carboxylic acid ethyl ester

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Reaction Steps

To N-(4-benzyloxyphenyl)-2,4-dichlorobenzamidine, from Ex. 1, Step 1 (6.88 g, 18.5 mmol) dissolved in 50 ml THF was added potassium carbonate (2.56 g, 18.5 mmol) and the suspension was stirred for 10 minutes. Ethyl-3-bromo-2-oxobutanoate (4.65 g, 22.2 mmol) was dropwise added over 1 hour, and the mixture was stirred for 66 hours at room temperature. The solution was filtered and evaporated to dryness. The residue was dissolved in acetic acid and refluxed for 1 hour. The mixture was cooled to room temperature, 100 ml water added and the product extracted with EtOAc (2×200 ml). The combined organic phases were washed with saturated sodium hydrogen carbonate, dried (Na2SO4), filtered and concentrated. Flash chromatography (silica, hexane:EtOAc 70:30, 60:40) afforded 5.75 g (65%) of the title compound as a pale yellow solid.

Provenance & Evidence