[Synthesis]
The general procedure for the synthesis of methyl 3-aminobenzofuran-2-carboxylate from the compound (CAS: 34844-79-6) was as follows: compound 2 (2.62 g, 13.9 mmol, 1.00 eq.) was dissolved in dry ether and transferred to an argon protected flask. Subsequently, potassium tert-butoxide (0.78 g, 6.9 mmol, 0.50 eq.) was slowly added and the reaction mixture was stirred at room temperature for 25 minutes. Upon completion of the reaction, the reaction was quenched by the addition of a small amount of water and the solvent was subsequently removed by evaporation. The residue was dissolved in water (30 mL) and extracted with diethyl ether (30 mL × 3). The organic phases were combined, dried with anhydrous sodium sulfate, filtered and the solvent was evaporated to give a light yellow crystalline product in 65% yield with a melting point of 94 °C. The product was characterized by 1H-NMR: δ=7.55 (d, J=7.9 Hz, 1H, H4), 7.48-7.41 (m, 2H, H7 and H6), 7.19-7.30 (m, 1H, H5), 5.00 (br s, 2H, NH2), 3.96 (s, 3H, COOCH3).13C-NMR data: δ=162.1 ( COOCH3), 154.3 (C7a), 138.9 (C3), 129.1 (C4), 125.6 (C3a), 122.5 (C5), 121.8 (C2), 119.8 (C6), 112.8 (C7), 51.7 (COOCH3). Results of mass spectrometry (EI, 70 eV) analysis: measured value 191 (calculated value for C10H9NO3: 191.19); m/z (% relative abundance) = 191 (M+, 100), 159 (50), 133 (25), 103 (90), 83 (20), 77 (50), 51 (25). |