2,6-Dichlorobenzoyl chloride → (S)-2-tert-butoxycarbonylamino-3-[4-(2,6-dichlorobenzoylamino)phenyl]propionic acid methyl ester

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Reaction Steps

To a solution of 4-amino-N-[(1,1-dimethylethoxy)carbonyl]-L-phenylalanine methyl ester (127.6 mmol, 37.57 g) and 2,6-dichlorobenzoyl chloride (140.6 mmol, 29.45 g) in dichloromethane (350 mL) was added diisopropylethylamine (192 mmol, 33.4 mL) at room temperature. The brown solution was stirred for 15 h at room temperature to afford a white suspension. At this time, TLC analysis of the mixture indicated the absence of starting material. The solids were collected by filtration and were washed with dichloromethane (150 mL) and air dried to obtain 52.75 g (88.4%) of a white solid: mp 192-194° C. 1H NMR (DMSO-d6) (400 MHz) δ 10.68 (s, 1H), 7.47-7.6 (m, 5H), 7.2-7.29 (m, 3H), 4.12-4.17 (m, 1H), 3.62 (s, 3H), 2.79-2.99 (m, 2H), 1.33 (s, 9H), 13C NMR, CDCl3 (100 Mhz) d 172.49, 161.82, 155.37, 136.99, 136.36, 131.28, 131.16, 129.48, 128.19, 119.31, 78.27, 55.3, 51.76, 35.9, 27.77. HR MS: Obs. mass, 466.1069. Calcd. mass, 466.1062).

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