Synthesis
General procedure for the synthesis of 2-hydroxymethylquinoline from methyl quinoline-2-carboxylate: a tetrahydrofuran (THF, 30 mL) solution of methyl quinoline-2-carboxylate (5 g, 26.8 mmol) was slowly added to a tetrahydrofuran (THF, 20 mL) solution containing sodium borohydride (NaBH4, 710 mg, 18.8 mmol) at room temperature. The reaction mixture was stirred at 35 °C for 30 min. Subsequently, methanol (2.5 mL), warm water (30 mL) and ethyl acetate (20 mL) were added sequentially at the same temperature. The organic layer was separated and washed with deionized water (2 x 30 mL). The organic phase was dried over anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (eluent: ethyl acetate/methylcyclohexane=60/40) to give a white solid product in 73% yield. The melting point of the product was 135 °C (decomposition). Nuclear magnetic resonance hydrogen spectrum (1H NMR, 300 MHz, CDCl3) showed: δ 4.68 (1H, s, OH), 4.95 (2H, s, CH2), 7.31 (1H, m, aromatic CH), 7.55 (1H, m, aromatic CH), 7.71 (1H, m, aromatic CH), 7.81 (1H, m, aromatic CH), 8.10 (2H , m, aromatic CH). The nuclear magnetic resonance carbon spectrum (13C NMR, 75 MHz, CDCl3) showed: δ 64.25, 118.43, 126.35, 127.55, 127.69, 128.57, 129.81, 136.86, 146.72, 159.19. Calculated values for elemental analysis (C10H9NO): C, 75.45; H, 5.70 Measured values (C10H9NO): C, 75.45; H, 5.70; N, 8.80; measured values: C, 75.13; H, 5.56; N, 8.75.
References
[1] Organic Letters, 2005, vol. 7, # 17, p. 3609 - 3612
[2] Tetrahedron Letters, 2012, vol. 53, # 35, p. 4747 - 4750
[3] Tetrahedron, 2013, vol. 69, # 44, p. 9322 - 9328
[4] Tetrahedron Asymmetry, 2009, vol. 20, # 14, p. 1672 - 1682
[5] Journal of Organic Chemistry, 1953, vol. 18, p. 55,56
