1-Methyl-2-pyrrolecarboxylic acid → HCID 86757056, Verbindung

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A mixture of methyl (E)-3-aminocinnamate (9) (1.20 g, 6.77 mmol), 1-methylpyrrole-2-carboxylic acid (0.89 g, 7.11 mmol) and EDCI.HCl (1.56 g, 8.14 mmol) in pyridine (8 mL) was stirred at 50° C. for 2.5 h and then cooled and diluted with water. The precipitated semi-solid was dissolved in CH2Cl2, the solution was washed with 0.5 N HCl (2×) and water (2×) and then dried and concentrated under reduced pressure below 30° C. The residue was chromatographed on silica gel, eluting with CH2Cl2/EtOAc (10:1), to yield a solid which was triturated with i-Pr2O/petroleum ether to give thermally unstable methyl (E) -3- (l-methylpyrrole-2-carboxamido)cinnamate (10) (1.42 g, 74%), mp 89-90° C. 1H NMR [(CD3)2SO] δ9.83 (s, 1 H, NH), 8.01 (d, J=1.4 Hz, 1 H, H-2), 7.76 (dt, J=7.8, 1.4 Hz, 1 H, H-4), 7.63 (d, J=16.0 Hz, 1 H, PhCH═CH), 7.45-7.35 (m, 2 H, H-5,6), 7.05 (dd, J=4.0, 1.7 Hz, 1 H, H-pyrrole), 7.03 (t, J=2.0 Hz, 1 H, H-pyrrole), 6.54 (d, J=16.0 Hz, 1 H, Ph CH═CH), 6.11 (dd, J=3.8, 2.6 Hz, 1 H, H-pyrrole), 3.89 (s, 3 H, NCH3), 3.74 (s, 3 H, CO2CH3).

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