N-BOC-4-amino-1-naphthoic acid (0.46 g, 1.60 mmol), methionine methyl ester hydrochloride (0.35 g, 1.76 mmol), EDCI (0.43 g, 1.76 mmol), HOBT (0.24 g, 1.76 mmol) and Et3N (0.27 ml) in CH2Cl2 (6.4 ml) were reacted as described for N-BOC-4-aminobenzoyl methionine methyl ester in Example 1. After workup and recrystallization from ethyl acetate and hexanes, 0.44 g (63.6%) of pale pink crystals were obtained. mp 131°-132° C.; 1H NMR (CDCl3) 1.57 (9 H, s), 2.11-2.21 (4 H, m), 2.29-2.41 (1 H, m), 2.65 (2 H, t, J=7.1 Hz), 3.83 (3 H, s), 4.99-5.06 (1 H, m), 6.68 (1 H, d, J=8.0), 7.02 (1 H, s), 7.56-7.59 (2 H, m), 7.69 (1 H, d, J=7.9 Hz), 7.87-7.90 (1 H, m), 8.02 (1 H, d, J=7.9 Hz), 8.44-8.48 (1 H, m); 13C NMR (CDCl3) 15.56, 28.31, 30.19, 31.65, 52.06, 52.64, 81.17, 115.82, 120.18, 125.79, 126.37, 126.53, 127.18, 131.02, 135.65, 152.93, 169.04, 172.40; HRMS calc. for C22 H28N2O5S, 432.1719; found 432.1702; m/z (FAB) 433 (M+1).
