Reaction SMILES: [K+].[Br-].O.[O:4]=[C:5]1[C:10]([NH:11][C:12](=[O:21])[CH2:13][CH2:14][C:15]2[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=2)=[CH:9][CH:8]=[C:7](C2C=CC=CC=2)[N:6]1[CH2:28][C:29]([NH:31][CH:32]([CH:37]=[O:38])[CH2:33][C:34]([OH:36])=[O:35])=[O:30]>CO>[O:4]=[C:5]1[C:10]([NH:11][C:12](=[O:21])[CH2:13][CH2:14][C:15]2[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=2)=[CH:9][CH:8]=[CH:7][N:6]1[CH2:28][C:29]([NH:31][CH:32]([CH:37]=[O:38])[CH2:33][C:34]([OH:36])=[O:35])=[O:30]
Reactant: O=CC(CC(=O)O)NC(=O)Cn1c(-c2ccccc2)ccc(NC(=O)CCc2ccccc2)c1=O
Agent: [Br-]
Agent: [K+]
Solvent: O
Solvent: CO
Product: O=CC(CC(=O)O)NC(=O)Cn1cccc(NC(=O)CCc2ccccc2)c1=O

Procedure:
3(S) 3-(1,2-Dihydro-2-oxo-6-phenethyl-3(3-phenyl-propionyl)amino-1-pyridyl)acetylamino-4-oxobutanoic acid (54c), was isolated (46%) as a white solid: IR (KBr) 337S, 1694, 1643, 1586, 1561, 1515, 1377, 1254, 1188, 1070; 1H NMR (CD3OD) 8.18 (1H, d, J=7.8), 7.22 (10H, m), 6.15 (1H, d, J=7.8), 4.75 (2H, s), 4.58 (1H, m), 4.30 (1H, m), 3.01-2.28 (10H, m); MS FAB+ M+=504 (M+1). 3(S) 3-(6-Butyl-1,2-dihydro-2-oxo-3-(3-phenylpropionyl)amino-1-pyridyl)acetylamino-4-oxobutanoic acid (54d), was isolated (90%) as colorless crystals: m.p. 120-5° C.; IR (KBr) 3315, 1784, 1679, 1644, 1589, 1561, 1556, 1520, 1415, 1379, 1186; 1H NMR (CD3OD) 8.22 (1H, d, J=7.8), 7.24 (5H, m), 6.22 (1H, d, J=7.8), 4.80 (2H, m), 4.60 (1H, s), 4.28 (1H, m), 2.98 (2H, m), 2.72 (2H, m), 2.58 (4H, m), 1.48 (4H, m), 0.97 (3H, t, J=7.1). Anal. Calcd for C24H29N3O6 0.5 H2O. C, 62.06; H, 6.51; N, 9.05. Found: C, 62.08; H, 6.43; N, 9.01. MS FAB+M+=456 (M+1). 3(S) 3-(1,2-Dihydro-6-methyl-2-oxo-3-(3-phenylpropionyl)amino-1-pyridyl)acetylamino-4-oxobutanoic acid (54e), was isolated (85%) as a colorless solid: mp. 129-138° C.; IR (KBr) 327, 3294, 1710, 1695, 1682, 1554, 1525, 1379, 1272, 1240; 1H NMR (CD3OD) δ 8.19 (1H, d, J=7.6), 7.19, (5H, m), 6.21 (1H, d, J=7.6), 4.80 (2H, m), 4.59 (1H, m), 4.30 (1H, m), 2.98 (2H, m), 2.72 (2H, m), 2.80-2.40 (2H, m), 2.30 (3H, s). Anal. Calcd for C21H22N3O6. H2O: C, 58.46; H, 5.84; N, 9.74. Found C: 58.82; H, 60.5; N, 9.42. 3(S) 3-(1,2-Dihydro-2-oxo-6-phenyl-3-(3-phenyl-propionyl)amino-1-pyridyl)acetylamino-4-oxobutanoic acid (54f), 73% as an off-white solid: m.p. 140° C. (decomp). [α]D24 −8.5° (c 0.1, MeOH). IR (KBr) 3302, 1796, 1726, 1679, 1643, 1590, 1560, 1516, 1490, 1449, 1420, 1398, 1376, 1231; 1H NMR (CD3OD) δ 8.36 (1H, d), 7.49-7.14 (10H, m), 6.27 (1H, dd), 4.54 (3H, m), 4.30 (1H, m), 3.0, 2.73 (2×2H, 2×m), 2.7-2.29 (2H, m). 3(S) 3-(1,2-Dihydro-2-oxo-3-(3-phenylpropionyl)amino-1-pyridyl)acetylamino-4-oxobutanoic acid (54 g; G), was isolated (73%) as a foam: mp. 140-5° C. (decomp); IR (KBr) 3352, 3314, 1719, 1700, 1668, 1649, 1600, 1559, 1514, 1379, 1261; 1H NMR (CD3OD) δ 8.32 (1H, d, J=7.5), 7.19 (6H, m), 6.34 (1H, t), 5.1-4.6 (3H, m), 4.32 (1H, m), 2.7 (6H, m). Anal. Calcd for C20H21N3O6. 0.6H2O: C, 58.50, H, 5.45, N, 10.24. Found: C, 58.43, H, 5.35, N. 9.85. MS FAB+M+=400 (M+1). 3(S), N(2(R,S)) 3-(2-(6-Benzyl-1,2-dihydro-2-oxo-3-(3-phenylpropionyl) amino-1-pyridyl)propionylamino)-4-oxobutanoic acid (54h), was obtained (69%) as a colorless foam: m.p. 120° C.; [α]D20 −16.0° (c, 0.11, CH2Cl2). IR (KBr) 3315, 1783, 1727, 1666, 1644, 1599, 1564, 1517, 1454, 1379; 1H NMR (CD3OD) δ 8.23 (1H, m), 7.27 (10H, m), 6.28 (1H, m), 4.84 (1H, m), 4.53 (1H, m), 4.22 (1H, m), 4.10 (2H, m), 2.96 (2H, m), 2.72 (2H, m), 2.39 (2H, m), 1.21 (3H, m). Anal. Calcd for C28H29N3O6. 1.25H2O: C, 63.93, H, 6.03, N, 7.99. Found: C, 63.98, H, 5.85, N, 7.86. MS FAB (+) M+=504 (M +1). 3(S) 3-(3-(2-Acetyl-L-tyrosinyl)amino-6-benzyl-1,2-dihydro-2-oxo-1-pyridyl)acetylamino-4-oxobutanoic acid (54%), was isolated (79%) as colorless crystals: mp. 193-6° C. (decomp.); IR (KBr) 3284, 1644, 1599, 1565, 1519, 1455, 1429, 1407, 1375, 1267, 1251; 1H NMR (d6-DMSO/CDCl3) δ 8.16 (1H, d, J=7.7), 7.26 (5H, m), 7.03 (2H, d, J=8.4), 6.61 (2H, d, J=8.4), 6.03 (1H, d, J=7.7), 4.58 (3H, m), 4.44 (1H, m), 4.13 (1H, m), 3.84 (2H, s), 3.07-2.30 (4H, m). Anal. Calcd for C29H30N4O8. 2H20: C, 58.19; H, 5.72; N, 9.36. Found: C, 58.11; H, 5.63; N, 9.29. MS FAB+M+=563 (M+1). 3(S) 3-(6-Benzyl-1,2-dihydro-2-oxo-3-(2-phenylethane-sulphonyl)amino-1-pydridyl)acetylamino-4-oxobutanoic acid (54j), was isolated (85%) as a colorless solid: mp. 102-5° C.; [α]D 23-9.9° (c 0.1, MeOH); IR (KBr) 3452, 3328, 3155, 1719, 1679, 1645, 1594, 1567, 1453, 1425, 1357, 1307, 1225, 1148, 1132; 1H NMR (CD3OD) δ 7.52 (1H, d, J=7.6), 7.33 (10H, m), 6.12 (1H, d, J=7.6), 4.73 (2H, m), 4.58 (1H, d, J=3.7), 4.34 (1H, m), 3.97 (2H, s), 3.29 (2H, m), 3.08 (2H, m), 2.75-2.37 (2H, m). Anal. Calcd for C26H27N3O7S. 1.7H2O: C, 56.14; H, 5.51; N, 7.55. Found: C, 56.20; H, 5.49; N, 7.29. MS FAB+M+=526 (M +1). 3(S) 3-(6-Benzyl-1,2-dihydro-2-oxo-3-(2-phenylethoxy)carbonylamino-1-pyridyl)acetylamino-4-oxobutanoic acid (54%), was isolated (54%) as an off-white solid: mp. 84-86° C.; IR (KBr) 3373-3310, 1787, 1726, 1691, 1649, 1599, 1567, 1517, 1367, 1215; 1H NMR (CD3OD) δ 7.93 (1H, bd, J=7.4), 7.37-7.18 (10H, m), 6.15 (1H, d, J=7.4), 4.77 (1H, d, J=3.7), 4.67 and 4.58 (2H, 2m), 4.35 (2H, t, J=6.9), 4.35 (1H, m), 3.94 (2H, s), 2.98 (2H, t, J=6.9), 2.76-2.39 (2H, m). 3(S) 3-(6-Benzyl-1,2-dihydro-2-oxo-3-(4-phenylbutyryl)carbonylamino-1-pyridyl)acetylamino-4-oxobutanoic acid (541), was isolated (50%) as a white solid: mp. 89-93° C.; IR (KBr) 3369-3302, 1678, 1645, 1594, 1565, 1517, 1379, 1258; 1H NMR (d4-methanol) δ 8.25 (1H, d, J=7.6), 7.37-7.18 (10H, m), 6.15 (1H, d, J=7.4), 4.74 (2H, m), 4.60 (1H, m), 4.30 (1H, m), 3.97 (2H, s), 2.76-2.37 (2H, m), 2.67 (2H, t), 2.45 (2H, t), 1.98 (2H, m). Anal. Calcd for C28H29N3O6. 1.5H2O: C, 63.39; H, 6.08; N, 7.92. Found C: 63.69; H, 5.74; N, 7.83.