3.01-3.10 (m, 1H, CHCH2Ph), 3.62-3.76 (m, 2H, CHCH2OH), 4.24-4.34 (m, 2H,

NCHCOx2), 4.26-4.48 (m, 1H, NCHCO), 4.92-4.94 (m, 2H, OCH2Ph), 7.20-7.34 (m,

10H), 7.53 (d, J= 8.8 Hz, 1H, NH), 8.04 (d, J= 7.7 Hz, 1H, NH), 8.19 (d, J= 7.4 Hz,

1H, NH), Two exchangeable protons (OH and CO2H) are missing. 1C NMR (DMSO-d6)

6 18.3, 37.3, 47.9, 54.5, 56.0, 61.2, 65.1, 126.1, 127.3, 127.6, 127.9, 128.2, 129.1, 136.9,

138.1, 155.8, 171.1, 171.7, 172.1. Anal. Calcd for C23H27N307: C, 60.38; H, 5.95; N,

9.18. Found: C, 59.84; H, 6.06; N, 9.10.

 (5S, 8S, 11S)-8-Benzyl-ll-(1H-indol-3-ylmethyl)-5-methyl-3,6,9-trioxo-1-

phenyl-2-oxa-4,7,10-triaza dodecan-12-oic acid (Z-Ala-Phe-Try-OH, 5.4f): Colorless

microcrystals (95%), mp 203-204 C: [a]25D = -6.90 (c 0.6, DMF); H NMR (DMSO-d6)

6 1.11 (d, J= 7.0 Hz, 3H, CHCH3), 2.77-2.85 (m, 1H, CHCH2Ar), 2.98-3.23 (m, 3H,

CHCH2Ar), 4.00 (t, J= 7.2 Hz, 1H, NCHCO), 4.45-4.60 (m, 2H, NCHCOx2), 4.97 (d, J

= 12.5 Hz, 1H, OCH2Ph), 5.03 (d, J= 12.5 Hz, 1H, OCH2Ph), 6.98 (t, J= 7.1 Hz, 1H),

7.06 (t, J= 7.5 Hz, 1H), 7.18-7.21 (m, 6H), 7.33-7.41 (m, 7H), 7.53 (d, J= 7.7 Hz, 1H,

NH), 8.01 (d, J= 8.0 Hz, 1H, NH), 8.32 (d, J= 5.6 Hz, 1H, NH), 11.0 (br s, 1H, NH),

One exchangeable proton is missing. 13C NMR (DMSO-d6) 6 18.1, 27.0, 37.5, 50.1, 53.0,

53.6, 65.4, 109.5, 111.4, 118.1, 118.3, 120.8, 123.8, 126.1, 127.2, 127.7, 127.9, 128.3,

129.3, 136.0, 136.9, 137.6, 155.5, 170.9, 172.1, 173.0. HRMS m/z calcd for C19H27N306

557.2400 (M), found 557.2400.

 (5S, 8S, 14S)-14-Isobutyl-5-benzyl-8-methyl-3,6,9,12-tetraoxo-l-phenyl-2-oxa-

4,7,10,13-tetraazapentadecan-15-oic acid (Z-Phe-Ala-Gly-Leu-OH, 5.5a): Colorless

microcrystals (86%), mp 207.5-208.5 oC: [a]25D = -11.2 (c 1.2, DMF); 1H NMR

(DMSO-d6) 6 0.83 (d, J= 6.3 Hz, 3H, CH(CH3)2), 0.88 (d, J= 6.3 Hz, 3H, CH(CH3)2),