Diisopropylethylamine → N-[2-chloro-4-[[[[3-[[(1,1-dimethylethyl) dimethylsilyl]oxy]phenyl]methyl]amino]carbonyl]-6-methylbenzoyl]-3-[[(1,1-dimethylethoxy)carbonyl]amino]-L-alanine, methyl ester

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Reaction Steps

Diisopropylethylamine (2.11 mL, 12.1 mmol) was added to a solution of 2-chloro-4-[[[[3-[[(1,1-dimethylethyl)dimethylsilyl]oxy]phenyl]methyl]amino]carbonyl]-6-methylbenzoic acid (Example 33; 1.32 g, 3.04 mmol) and 3-[[(1,1-dimethylethoxy)carbonyl]amino]-L-alanine, methyl ester, hydrochloride (1.54 g, 6.05 mmol) in dichloromethane (15 mL). Benzotriazol-1-yloxy-tris-(dimethylamino)-phosphonium hexafluorophosphate (BOP reagent; 1.48 g, 3.35 mmol) was added and the mixture was stirred at room temperature for 4 h. The solution was diluted with ethyl acetate, washed with 1 M HCl, water, saturated aqueous sodium hydrogen carbonate, and water. The solution was then dried (MgSO4), filtered, evaporated, and chromatographed (40% ethyl acetate/petroleum ether) to give N-[2-chloro-4-[[[[3-[[(1,1-dimethylethyl)dimethylsilyl]oxy]phenyl]methyl]amino]carbonyl]-6-methylbenzoyl]-3-[[(1,1-dimethylethoxy)carbonyl]amino]-L-alanine, methyl ester (1.57 g, 81%) as a white foam

Provenance & Evidence