2-(Trifluoromethyl)aniline → N-(2-trifluoromethyl-phenyl)-malonamic acid benzyl ester

Participants

Reaction Steps

A solution of mono-benzyl malonate (890 mg, 4.6 mmol) in 3:1 CH2Cl2/DMF (24 mL) was treated sequentially with N,N-diisopropylethylamine (2.0 mL, 11.5 mmol), 2-trifluoromethyl-phenylamine (0.6 mL, 4.6 mmol), and HATU (2.1 g, 5.5 mmol). The mixture was stirred for 12 h at RT, concentrated in vacuo, and partitioned between EtOAc and sat. NH4Cl. The aqueous phase was extracted with EtOAc (1×). The combined organic extracts were washed with sat. NaHCO3 and brine, dried (Na2SO4), filtered, and concentrated in vacuo. The residue was purified by flash chromatography to provide N-(2-trifluoromethyl-phenyl)-malonamic acid benzyl ester as an oil (894 mg, 57% yield). This material was dissolved in EtOAc (35 mL). The resultant solution was charged with 10% Pd/C (178 mg), stirred under H2 (1 atm) for 12 h at RT, filtered, and concentrated in vacuo to provide N-(2-trifluoromethyl-phenyl)-malonamic acid (621 mg, 95% yield). A portion of this material (100 mg, 0.4 mmol) was combined with [(2S,3S)-2-amino-3-hydroxy-hex-4-ynyl]-carbamic acid benzyl ester (150 mg, 0.4 mmol, prepared as described in WO PCT 0250019) and dissolved in 6 mL of 3:1 CH2Cl2/DMF. The resultant solution was charged sequentially with N,N-diisopropylethylamine (0.35 mL, 1.5 mmol) and HATU (182 mg, 0.48 mmol). The mixture was stirred for 12 h at RT, concentrated in vacuo, and partitioned between EtOAc and sat. NH4Cl. The aqueous phase was extracted with EtOAc (1×). The combined organic extracts were washed with sat. NaHCO3 and brine, dried (Na2SO4), filtered, and concentrated in vacuo. The residue was purified by flash chromatography to provide {(2S,3S)-3-hydroxy-2-[2-(2-trifluoromethyl-phenylcarbamoyl)-acetylamino]-hex-4-ynyl}-carbamic acid benzyl ester (54 mg, 28% yield). MS found: (M+Na)+=514.5.

Provenance & Evidence