Synthesis
General procedure for the synthesis of 2-amino-5-fluorobenzamide from 2-amino-5-fluorobenzoic acid: A solution of 2-amino-5-fluorobenzoic acid (3 g, 19.34 mmol) in tetrahydrofuran (64.5 mL) was added to a round-bottomed flask, and a toluene solution of 20% phosgene (11.2 mL, 21.3 mmol) was slowly added dropwise. The reaction mixture was stirred at room temperature for 18 h. The mixture was subsequently cooled to 0 °C and concentrated ammonium hydroxide solution (27.9 mL, 193 mmol) was carefully added. The mixture was gradually warmed to room temperature and stirring was continued for 1 hour. After completion of the reaction, the organic phase was diluted with ethyl acetate, washed sequentially with aqueous dipotassium hydrogen phosphate and saturated brine, dried over anhydrous sodium sulfate and concentrated to give the white solid product 2-amino-5-fluorobenzamide (2.46 g, 82% yield). Mass spectral data: M(C7H7FN2O) = 154.14, (M + H - NH3)+ = 138.
References
[1] Patent: US2008/182852, 2008, A1. Location in patent: Page/Page column 28
[2] Molecules, 2017, vol. 22, # 2,
[3] Patent: WO2018/125961, 2018, A1. Location in patent: Page/Page column 77
[4] Journal of Medicinal Chemistry, 2000, vol. 43, # 23, p. 4479 - 4487
[5] Patent: US6479499, 2002, B1
