Synthesis of Peptidomimetics
1887
phenylacetaldehyde (60 mg, 0.5 mmol), and 3 (140 mg, 0.5 mmol), 7 was
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obtained as a colorless oil in 8.6% yield (35 mg). H NMR (CDCl3) d 8.451
(s, 1H, CO–NH–), 7.768–7.547 (m, 15H, 3Ph–), 5.631 (m, 1H, –CH55),
5.541 (s, 1H, BocNH–), 5.487 (m, 1H, –CH55), 5.302 (m, 3H, 3N–CH–
CO), 5.147 (s, 4H, 2OCH2Ph), 4.128 (t, 2H, NCH2–), 4.104 (s, 3H,
–OCH3), 4.011 (t, 2H, PhCH2–), 3.678 (s, 3H, –NCH3), 2.324 (m, 4H,
2COCH2–), 1.950 (m, 1H, –CH–), 1.435 (s, 9H, Boc), 1.323 (m, 8H,
4CH2–). MS (ESI): 827.0 (Mþ).
Following the same procedure as with 6, from Boc-Asp(Obzl)-OH (4b,
160 mg, 0.5 mmol), 3-methylbutyl amine (5a, 20 mg, 0.5 mmol), phenylacetal-
dehyde (60 mg, 0.5 mmol), and 3 (140 mg, 0.5 mmol), 8 was obtained as a
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colorless oil in 12% yield (47 mg). H NMR (CDCl3) d 8.497 (s, 1H, CO–
NH–), 7.813–7.585 (m, 15H, 3Ph–), 5.481 (s, 1H, BocNH–), 5.311
(m, 3H, 3N–CH–CO), 5.094 (s, 4H, 2OCH2Ph), 4.204 (t, 2H, NCH2–),
4.082 (s, 3H, –OCH3), 4.043 (t, 2H, PhCH2–), 3.757 (s, 3H, –NCH3),
2.895 (m, 4H, 2COCH2–), 1.435 (s, 9H, Boc), 1.388 (m, 1H, –CH–),
1.235 (m, 2H, –CH2–), 1.108 (d, 3H, –CH3), 1.002 (d, 3H, –CH3). MS
(ESI): 789.0 (Mþ).
Following the same procedure as with 6, from Fmoc-Asp(Obzl)-OH (4c,
205 mg, 0.5 mmol), 2-(1-cyclohexenyl)ethylamine (5b, 65 mg, 0.5 mmol),
phenylacetaldehyde (60 mg, 0.5 mmol), and 3 (140 mg, 0.5 mmol), 9 was
obtained as a colorless oil in 30% yield (142 mg). 1H NMR (CDCl3)
d 8.468 (s, 1H, CO–NH–), 7.852–7.523 (m, 23H, Ar–), 5.834 (s, 1H,
FmocNH–), 5.627 (m, 1H, –CH55), 5.573 (m, 1H, –CH55), 5.338 (m, 3H,
3N–CH–CO), 5.205 (s, 4H, 2OCH2Ph), 4.709 (d, 2H, OCH2–), 4.461
(m, 1H, ArCHAr), 4.102 (t, 2H, NCH2–), 4.092 (s, 3H, –OCH3), 3.996
(t, 2H, PhCH2–), 3.711 (s, 3H, –NCH3), 2.469 (m, 4H, 2COCH2–), 1.976
(m, 1H, –CH–), 1.550 (m, 8H, 4CH2–). MS (ESI): 949.7 (Mþ).
Following the same procedure as with 6, from Fmoc-Asp(Obzl)-OH (4c,
205 mg, 0.5 mmol), 3-methylbutyl amine (5a, 20 mg, 0.5 mmol), phenylacetal-
dehyde (60 mg, 0.5 mmol), and 3 (140 mg, 0.5 mmol), 10 was obtained as a
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colorless oil in 16% yield (73 mg). H NMR (CDCl3) d 8.531 (s, 1H, CO–
NH–), 7.864–7.539 (m, 23H, Ar–), 5.893 (s, 1H, FmocNH–), 5.347
(m, 3H, 3N–CH–CO), 5.340 (s, 4H, 2OCH2Ph), 4.716 (d, 2H, OCH2–),
4.458 (m, 1H, ArCHAr), 4.097 (t, 2H, NCH2–), 4.052 (s, 3H, –OCH3),
3.988 (t, 2H, PhCH2–), 3.696 (s, 3H, –NCH3), 2.880 (m, 4H, 2COCH2–),
1.405 (m, 1H, –CH–), 1.261 (m, 2H, –CH2–), 1.079 (d, 3H, –CH3), 0.992
(d, 3H, –CH3). MS (ESI): 911.0 (Mþ).
Following the same procedure as with 6, from b-phenyl propionic acid
(4a, 75 mg, 0.5 mmol), 4-amino-1-phenylpiperazine (5c, 89 mg, 0.5 mmol),
phenylacetaldehyde (60 mg, 0.5 mmol), and 3 (140 mg, 0.5 mmol), 11 was
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obtained as a colorless oil in 12% yield (42 mg). H NMR (CDCl3) d 8.564
(s, 1H, CO–NH–), 7.749–6.607 (m, 20H, 4Ph–), 5.286 (m, 2H, 2N
–CHCO–), 5.193 (s, 2H, –OCH2Ph), 4.313 (t, 2H, PhCH2–), 4.248 (t, 2H,
PhCH2–), 4.101 (s, 3H, –OCH3), 3.825 (s, 3H, –NCH3), 3.470 (t, 4H,