Cesium carbonate → ethyl 1-(5-chloro-2-nitrobenzyl)-4-methyl-1H-pyrrole-2-carboxylate

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Reaction Steps

Under a nitrogen atmosphere with stirring add cesium carbonate (96 g, 295 mmoles) to a solution of ethyl 4-methyl-1H-pyrrole-2-carboxylate (30 g, 196 mmoles) in DMF (240 mL) and heat the reaction mixture to 40° C. to 45° C. for 1 hour. Cool the reaction mixture to room temperature and add a solution of 2-(bromomethyl)-4-chloro-1-nitro-benzene (54 g, 216 mmoles) in DMF (120 mL) drop-wise. Stir the resulting suspension for 1.5 h to 2.0 h, filter the solids and rinse the filtercake with DMF (45 mL). Transfer the solids to a clean reaction vessel, add water (200 mL) and cool the suspension to 10° C. to 15° C. with stirring for 1 h to 2 h. Filter the suspension, rinse with water (75 mL) and transfer the solids to another reaction vessel. Add ethanol (125 mL) and stir the suspension at 5° C. to 10° C. for 1 h to 2 h. Filter the solids, rinse the filtercake with ethanol (20 mL), and dry the solids in an oven at less than 50° C. under reduced pressure to give ethyl 1-(5-chloro-2-nitrobenzyl)-4-methyl-1H-pyrrole-2-carboxylate as a yellow solid (54 g, 94.1% purity, 73.3% yield).

Provenance & Evidence