(S)-4-(3-tert-butoxycarbonylmethyl-ureido)-5-(3'-chloro-biphenyl-4-yl)-2-methyl-pentanoic acid ethyl ester → (2R,4S)-4-(3-Carboxymethyl-ureido)-5-(3'-chloro-biphenyl-4-yl)-2-methyl-pentanoic acid ethyl ester

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Reaction Steps

Next, a solution of (S)-4-(3-tert-butoxycarbonylmethyl-ureido)-5-(3′-chloro-biphenyl-4-yl)-2-methyl-pentanoic acid ethyl ester (261 mg, 59.1 mmol) in 8 mL of methylene chloride/TFA (1:1) is stirred at room temperature for 1 hour. The solvent is removed under reduced pressure and the residue is purified by preparative HPLC using a gradient of 10% MeCN/water to 100% MeCN (0.1% TFA) and the product is further purified by chiral HPLC on a Chirapak OD-H column using heptane/ethanol (90:10) (0.1% TFA) to elute the title compound; HPLC Retention time 1.48 minutes (condition C): MS 447.3 (M+1); 1H NMR (400 MHz, DMSO-d6): δ ppm 1.03-1.05 (d, J=7.07 Hz, 3H), 1.08-1.12 (t, J=7.33 Hz, 3H), 1.27-1.34 (m, 1H), 1.70-1.76 (m, 1H), 2.62-2.67 (m, 1H), 2.71-2.76 (m, 2H), 3.66-3.68 (d, J=5.81 Hz, 2H), 3.71-3.78 (m, 1H), 3.95-4.00 (q, J=7.07 Hz, 14.40 Hz, 2H), 5.94-5.97 (t, J=5.56 Hz, 1H), 6.07-6.09 (d, J=8.34 Hz, 1H), 7.25-7.28 (m, 2H), 7.38-7.41 (m, 1H), 7.45-7.49 (t, J=7.83 Hz, 1H), 7.60-7.63 (m, 3H), 7.69-7.70 (t, J=1.77 Hz, 1H), 12.42 (s, 1H).

Provenance & Evidence