Sulfuric Acid → ethyl 4-(tert-butyl)-3,5-dimethyl-1H-pyrrole-2-carboxylate

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Reaction Steps

A solution of acetic acid (5.0 ml), sulfuric acid (1.2 ml), ethyl 3,5-dimethylpyrrole-2-carboxylate 5a (5.0 g, 0.03 mol) and tert-butyl acetate (3.5 g, 0.03 mol) was heated at 75° C. for 2 h and combinedwith sodium carbonate (8 g) in ice water (100 ml) to bring about the precipitation of ethyl 3,5-dimethyl-4-tert-butylpyrrole-2-carboxylate 4g as a colorless solid, mp 108°-110° C. (lit. 107°-109° C.), 3.1 g (47%); 1H NMR (CDCl3): δ 9.80 (s, 1H), 4.28 (q, 2H), 2.43 (s, 3H), 2.39 (s, 3H), 1.35 (s, 9H), 1.33 (t, 3H).

Provenance & Evidence