Reaction Steps
Cbz-Ala-Phe-VS-Ph was treated with butyllithium and tert-butylhydroperoxide in freshly distilled THF, as described with Cbz-Leu-Phe-VS-Ph above, to give Cbz-Ala-Phe-AS-Ph as a white powder, yield 93%. 1H-NMR (CDCl3) δ 1.21 (d, 3H, Ala-CH3), 3.80 (m, 4H, CH2-Phe and CH2—SO2), 4.12 (q, 1H, α-H), 4.88 (t, 1H, CH═), 5.11 (m, 3H, NH and Cbz), 7.30 (m, 10H, 2×Ph), 7.50 (t, 2H, SO2-Ph), 7.64 (t, 1H, SO2-Ph), 7.83 (d, 2H, SO2-Ph), 8.40 (b, 1H, NH). 13C NMR (400 MHz, CDCl3) δ 172.1, 156.3, 144.4, 140.8, 135.7, 134.2, 133.6, 131.2, 129.5, 129.4×2, 129.3, 128.8×2, 128.7, 128.6, 128.4, 128.3, 127.8, 127.3, 126.9, 107.2, 67.6, 51.7, 51.6, 40.2, 19.4. MS (FAB+) m/z 493 (M+1, 100%). HRMS calcd. for C27H29N2O5S: 493.17972. Obsd. 493.17663. Anal. calcd. for C27H28N2O5S: C, 65.83; H, 5.73; N, 5.69. Found: C, 65.73; H, 5.82; N, 5.68.
