1,4-Dibromobutane → 3-Methyl-4-pyrrolidin-1-yl-benzofuran-2-carboxylic acid ethyl ester

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Reaction Conditions

Reaction Steps

To 4-amino-3-methyl-benzofuran-2-carboxylic acid ethyl ester (500 mg, 2.28 mmol, 1 eq., prepared according to Example 60, Step 1) were added toluene (3 mL), 1,4-dibromobutane(272 uL, 2.28 mmol, 1 eq.), and N,N-diisopropylethylamine (953 uL, 5.47 mmol, 2.4 eq.) under argon in a sealed tube and the mixture was heated at 110° C. for 16 hours. After work-up and flash column chromatography, 3-methyl-4-pyrrolidin-1-yl-benzofuran-2-carboxylic acid ethyl ester was obtained in 48% yield. 1H NMR (400 MHz, DMSO-d6) δ ppm 1.3 (t, J=7.1 Hz, 3 H) 1.9 (m, 4 H) 2.7 (s, 3 H) 3.1 (m, 4 H) 4.3 (q, J=7.1 Hz, 2 H) 6.8 (dd, J=8.0, 0.6 Hz, 1 H) 7.2 (dd, J=8.3, 0.8 Hz, 1 H) 7.3 (m, 1 H).

Provenance & Evidence