Synthesis
General method: 2-nitro-5-chlorobenzaldehyde (1 eq.) was dissolved in ethanol (0.44 M) and cooled in an ice bath. To this cooled solution, sodium borohydride (1.5 eq.) was added in batches under stirring. The reaction mixture was kept stirred at 0 °C for 2 h. The progress of the reaction was monitored by thin layer chromatography (TLC). Upon completion of the reaction, the solvent was removed by careful evaporation to give a semi-solid product. Subsequently, the reaction was quenched by slow addition of saturated aqueous ammonium chloride solution until the hydrogen release was complete. The aqueous phase was extracted four times with dichloromethane (CH2Cl2) and the organic phase was combined. The organic phase was washed sequentially with water and saturated brine, dried over anhydrous magnesium sulfate and filtered. Finally, the solvent was removed by concentration under reduced pressure to give the crude product 5-chloro-2-nitrobenzenemethanol (12), which can be used in subsequent reactions without further purification.
References
[1] Angewandte Chemie - International Edition, 2017, vol. 56, # 35, p. 10573 - 10576
[2] Angew. Chem., 2017, vol. 129, # 35, p. 10709 - 10712,4
[3] Synlett, 2017, vol. 28, # 14, p. 1724 - 1728
[4] Bioorganic and Medicinal Chemistry, 2006, vol. 14, # 16, p. 5562 - 5577
[5] Journal of the American Chemical Society, 1952, vol. 74, p. 536
