Trifluoroacetic acid → Pentanoic acid, 4-[([1,1'-biphenyl]-4-ylcarbonyl)amino]-5-[[2-(4-fluorophenyl)-1,1-dimethylethyl]amino]-5-oxo-, (4S)-

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Reaction Steps

To a suspension of Compound 5 (100 g) in toluene (325 ml) were added trifluoroacetic acid (TFA, 313 g) at 5 to 20° C. The resulting solution was stirred at ambient temperature until the reaction was completed (4 to 6 h). TFA was removed by vacuum distillation, the solution diluted with ethyl acetate, washed with aqueous potassium acetate, and crystallization was affected by adding heptane to afford Compound 6 as white solid (82.7 g, yield 92%; Purity—99.8% (HPLC area %); Strength—98.0%; ee—99.0%). NMR data: 1.37, 1.45-s, 6H, CH3; 2.10-m, 2H, CH2; 2.35-2.60-m, 2H, CH2; 2.80-3.10-d, 2H, CH2; 4.80-q, 1H, CH; 6.80-7.80-m, 13H, Ph; 7.90-s, 2H, NH.

Provenance & Evidence