1420 J . Org. Chem., Vol. 65, No. 5, 2000
Taylor and Weir
1
-10.3° (c 1.12, EtOH); H NMR (CDCl3, 200 MHz) δ 1.35 (s,
(55 mg, 0.124 mmol, 1.05 equiv). The mixture was stirred at
room temperature for 3 h and then concentrated. The residue
was applied to a flash column and eluted with CH2Cl2 and then
2% MeOH in CH2Cl2 to give pentapeptide 33 as an oil (115
mg; 94%): TLC Rf 0.40 (2:1 EtOAc-hexanes); [R]20D ) -13.1°
(c 0.65, CHCl3); 1H NMR (CDCl3, 200 MHz) δ 1.15 (s, 9H), 1.28
(d, J ) 8.6 Hz, 4H), 1.31 (s, 9H), 1.41 (s, 9H), 1.60-2.54 (m,
6H), 3.06 (d, J ) 5.4 Hz, 2H), 3.34 (t, J ) 7.8 Hz, 1H), 3.63-
3.94 (m, 2H), 4.23 (q, J ) 6.8 Hz, 1H), 4.27-4.50 (m, 4H), 4.55
(d, J ) 5.7 Hz, 2H), 4.70-4.89 (m, 2H), 5.01 (br s, 1H), 5.20
(dd, J ) 6.4 Hz, 1.2 Hz, 1H), 5.27 (dd, J ) 13.0, 1.1 Hz, 1H),
5.58 (br d, 1H), 5.75-5.92 (m, 1H), 6.88 (d, J ) 8.5 Hz, 2H),
7.01 (d, J ) 8.5 Hz, 2H), 7.30-7.43 (m, 4H), 7.59 (d, J ) 7.2
Hz, 2H), 7.76 (d, J ) 7.2 Hz, 2H); 13C NMR (CDCl3, 50 MHz)
δ 14.0, 19.1, 21.8, 24.9, 27.2, 28.3, 28.7, 29.1, 31.7, 36.6, 37.3,
39.9, 47.0, 47.4, 50.3, 52.8, 53.4, 60.1, 61.0, 65.7, 67.0, 74.1,
78.2, 78.7, 118.7, 119.8, 123.9, 125.0, 126.9, 127.5, 129.6, 130.5,
131.3, 141.1, 143.6, 143.8, 154.2, 155.8, 156.0, 169.5, 169.7,
170.6, 171.2, 172.1; HRMS (FAB) calcd for (M + H)+
C57H79N6O12 1039.57556, obsd 1039.57726.
9H), 1.17-1.78 (m, 6H), 3.02 (q, J ) 5.8 Hz, 2H), 4.13 (t, J )
7.0 Hz, 1H), 4.29-4.34 (m, 2H), 4.56 (d, J ) 5.6 Hz, 2H), 5.17
(dd, J ) 10.4, 1.5 Hz, 1H), 5.24 (dd, J ) 17.2, 1.5 Hz, 1H),
5.40 (br d, J ) 7.6 Hz, 1H), 5.79 (ddt, J ) 17.2, 10.4, 5.6 Hz,
1H), 7.17-7.35 (m, 4H), 7.52 (d, J ) 7.0 Hz, 2H), 7.67 (d, J )
7.0 Hz, 2H). 13C NMR (CDCl3, 50 MHz) δ 22.3, 28.4, 29.5, 32.1,
40.0, 47.1, 53.7, 65.9, 66.9, 79.1, 118.9, 119.9, 125.0, 127.0,
127.6, 131.4, 141.2, 143.7, 143.8, 156.0 (2C), 172.1; HRMS
(FAB) calcd for M+ C29H36N2O6 508.25733, obsd 508.25893.
F m oc-P r o-Ser (OtBu )-Tyr (OtBu )-OAll (27). Diethylamine
(2 mL) was added to a suspension of Fmoc-Tyr(OtBu)-OAll (25)
(125 mg, 0.270 mmol, 1.00 equiv) in dry acetonitrile (2 mL).
The solution was stirred at room temperature under N2 for
30 min and then concentrated. The residue was taken up in
acetonitrile (3 mL) and concentrated again. The residue was
dissolved in dry CH2Cl2 (3 mL) and cooled to 0 °C. Diisopro-
pylethylamine (113 µL, 84 mg, 0.648 mmol, 2.40 equiv) was
added, followed by Fmoc-Pro-Ser(OtBu)-OH (21) (136 mg, 0.283
mmol, 1.0 equiv), and finally BOP reagent (125 mg, 0.283
mmol, 1.05 equiv). The flask was flushed with N2, stoppered,
and left to stir for 3 days. The orange solution was concen-
trated, and the product was isolated by flash column chroma-
tography, eluting with 1:1 EtOAc-hexanes to give tripeptide
27 as a colorless oil (194 mg; 97%): TLC Rf 0.30 (1:1 EtOAc-
hexanes); [R]20D ) -5.0° (c 0.60, CHCl3); 1H NMR (CDCl3, 200
MHz) δ 1.12 (s, 9H), 1.30 (s, 9H), 1.8-2.3 (m, 2H), 3.05 (m,
2H), 3.39-3.77 (m, 6H), 4.24-4.50 (m, 6H), 4.54 (d, J ) 5.8
Hz, 2H), 4.80 (m, 1H), 5.20 (dd, J ) 10.3, 1.3 Hz, 1H), 5.25 (d,
J ) 17.1, 1.3 Hz, 1H), 5.72-5.89 (m, 1H), 6.86 (d, J ) 8.3 Hz,
2H), 6.98-7.00 (m, 2H), 7.30-7.48 (m, 4H), 7.55-7.58 (m, 2H),
7.76 (d, J ) 7.0 Hz, 2H); 13C NMR (CDCl3, 100 MHz) δ 24.6,
27.3, 28.8, 29.1, 37.4, 47.0, 47.2, 53.0, 53.5, 60.8, 61.0, 65.8,
67.7, 74.0, 78.3, 118.7, 119.9, 124.0, 125.0, 127.0, 127.7, 129.7,
130.5, 131.5, 141.2, 143.9, 154.4, 155.8, 170.7, 171.7, 172.4;
HRMS (FAB) calcd for (M + H)+ C43H54N3O8 740.39111, obsd
740.39289.
Fm oc-Ala-Lys(ꢀ-Boc)-P r o-Ser (OtBu )-Tyr (OtBu )-OH (11).
Pd(PPh3)4 (13 mg, 0.011 mmol, 0.1 equiv) and dimedone (46
mg, 0.329 mmol, 3.0 equiv) were added to a solution of ester
33 (114 mg, 0.110 mmol, 1.0 equiv) in THF (4 mL), and the
solution was stirred at room temperature, under N2, in a flask
wrapped in aluminum foil, for 2 h. The mixture was concen-
trated, and the orange residue was purified by RP-HPLC to
give pentapeptide acid 2 (83 mg, 75%) as a colorless solid.
HPLC conditions: 10 µm C-18 column, 21 mm diameter, flow
rate 12 mL min-1, using 75% MeCN in H2O (with 0.1% added
TFA); tR 10.5 min. TLC Rf 0.37 (9:1 CH2Cl2-MeOH); [R]20
)
D
1
-16.9° (c 0.35, CHCl3); H NMR (CDCl3, 200 MHz) δ 1.13 (s,
9H), 1.30 (s, 9H), 1.42 (s, 9H), 1.80-2.05 (m, 6H), 3.05-3.68
(m, 8H), 4.20-4.72 (m, 12 H), 6.87 (d, J ) 8.4 Hz, 2H), 7.07
(d, J ) 8.4 Hz, 2H), 7.26-7.42 (m, 4H), 7.57 (br m, 2H), 7.75
(d, J ) 7.0 Hz, 2H); HRMS (FAB) calcd for M+ C54H75N6O12
999.54430, obsd 999.545187.
F m oc-Lys(ꢀ-Boc)-P r o-Ser (OtBu )-Tyr (OtBu )-OAll (31).
Diethylamine (2 mL) was added to a suspension of tripeptide
27 (88 mg, 0.119 mmol, 1.00 equiv) in acetonitrile (2 mL). The
solution was stirred at room temperature under N2 for 30 min
and then concentrated. The residue was taken up in acetoni-
trile (5 mL) and concentrated again. The residue was dissolved
in CH2Cl2 (3 mL). Fmoc-Lys(ꢀ-Boc)-OH (28) (59 mg, 0.125
mmol, 1.05 equiv) was added, followed by diisopropylethy-
lamine (31 µL, 23 mg, 0.178 mmol, 1.5 equiv) and BroP reagent
(48 mg, 0.125 mmol, 1.05 equiv). The mixture was stirred at
room temperature under N2 for 3 h and then concentrated.
The residue was applied to a flash column and eluted with
3:1 EtOAc-hexanes to give tetrapeptide 31 as an oil (114 mg;
99%): TLC Rf 0.27 (2:1 EtOAc-hexanes); tR 13.6 min (85%
MeCN; 15% H2O with 0.1% TFA) at 0.6 mL min-1 on a 4.6
F m oc-Th r (OtBu )-DOP A(OTBS)2-Lys(ꢀ-Boc)-OAll (38). A
solution of 36 (421 mg, 0.828 mmol, 1.00 equiv) in acetonitrile
(3 mL) and diethylamine (3 mL) was stirred at room temper-
ature under N2 for 30 min and then concentrated. The residue
was slurried with acetonitrile and concentrated a second time.
A solution of dipeptide acid 22 (700 mg, 0.869 mmol, 1.05
equiv) in CH2Cl2 (3 mL; 1 mL rinse) was added to the residue
under N2. N-Methylmorpholine (137 µL, 126 mg, 1.24 mmol,
1.5 equiv) was added, followed by BOP reagent (384 mg, 0.869
mmol, 1.05 equiv). The mixture was stirred at room temper-
ature for 3 days and then concentrated. The product was
isolated from the residue by flash chromatography, eluting
with 3:1 hexanes-EtOAc, increasing the polarity to 2:1 hex-
anes-EtOAc to give 38 (800 mg, 90%). TLC Rf 0.33 (2:1
hexanes-EtOAc); [R]20 ) +2.6° (c 1.2, CHCl3); 1H NMR
D
mm C18 column); [R]20 ) -7.4° (c 0.92, CHCl3); 1H NMR
(CDCl3, 400 MHz) δ 0.17 (s, 12H), 0.9-1.9 (m, 6H), 0.96 (s,
18H), 1.05 (d, J ) 6.2 Hz, 3H), 1.19 (s, 9H), 1.43 (2, 9H), 1.43
(s, 9H), 2.98-3.00 (m, 2H), 3.07 (q, J ) 6.1 Hz, 2H), 4.09-
4.15 (m, 2H), 4.22 (t, J ) 7.0 Hz, 1H), 4.38 (d, J ) 7.0 Hz,
2H), 4.55 (q, J ) 6.8 Hz, 1H), 4.61 (dd, J ) 5.8 Hz, 2H), 5.26
(dd, J ) 10.4, 1.2 Hz, 1H), 5.33 (dd, J ) 17.2, 1.2 Hz, 1H),
5.89 (ddt, J ) 17.2, 10.4, 5.6 Hz, 1H), 6.63 (dd, J ) 8.1, 2.0
Hz, 1H), 6.68 (d, J ) 6.0 Hz, 1H), 6.74 (d, J ) 8.1 Hz, 1H),
7.23 (br d, J ) 8.0 Hz, 1H), 7.31 (t, J ) 7.5 Hz, 2H), 7.40 (t, J
) 7.5 Hz, 2H), 7.60 (d, J ) 7.3 Hz, 2H), 7.76 (d, J ) 7.5 Hz,
2H); 13C NMR (CDCl3, 50 MHz) δ 1.3, 16.8, 18.3, 22.3, 25.8,
28.0, 28.3, 29.6, 31.9, 36.8, 40.1, 47.1, 52.2, 54.1, 58.5, 65.8,
66.5, 66.9, 75.6, 79.0, 118.9, 119.9, 120.8, 122.0, 125.0, 127.0,
127.6, 129.1, 131.5, 141.2, 143.6, 143.8, 145.9, 146.8, 155.9,
D
(CDCl3, 200 MHz) δ 1.17 (s, 9H), 1.32 (s, 9H), 1.43 (s, 9H),
1.8-2.3 (m, 8H), 3.08 (m, 4H), 3.30-3.43 (m, 1H), 3.55-3.84
(m, 5H), 4.21 (t, J ) 7.0 Hz, 1H), 4.37 (d, J ) 7.0 Hz, 2H),
4.30-4.62 (m, 5H), 4.57 (d, J ) 7.0 Hz, 2H), 4.85 (m, 1H),
5.21-5.33 (m, 2H), 5.67 (d, J ) 8.5 Hz, 1H), 5.68-5.99 (m,
1H), 6.88 (d, J ) 8.4 Hz, 2H), 7.02 (d, J ) 8.4 Hz, 2H), 7.26-
7.44 (m, 4H), 7.60 (d, J ) 7.6 Hz, 2H), 7.76 (d, J ) 7.6 Hz,
2H); 13C NMR (CDCl3, 50 MHz) δ 22.0, 24.9, 27.2, 28.5, 28.7,
29.3, 29.5, 32.1, 37.1, 40.0, 47.0, 47.3, 52.1, 52.9, 53.3, 60.2,
61.0, 65.7, 66.8, 74.3, 78.4, 78.9, 118.7, 119.8, 124.0, 125.0,
126.9, 127.6, 129.6, 130.6, 131.4, 141.1, 143.6, 143.8, 154.4,
156.1, 169.9, 170.8, 171.1, 171.8; HRMS (FAB) calcd for (M +
H)+ C54H74N5O11 968.53848, obsd 968.53776.
Fm oc-Ala-Lys(ꢀ-Boc)-P r o-Ser (OtBu )-Tyr (OtBu )-OAll (33).
Diethylamine (2 mL) was added to a solution of tetrapeptide
31 (114 mg, 0.118 mmol, 1.00 equiv) in acetonitrile (2 mL).
The solution was stirred for 30 min at room temperature under
N2 and then concentrated. The residue was taken up in
acetonitrile (5 mL) and concentrated again. The residue was
dissolved in CH2Cl2 (3 mL), and Fmoc-Ala-OH (30) (38 mg,
0.124 mmol, 1.05 equiv) was added, followed by triethylamine
(25 µL, 18 mg, 0.177 mmol, 1.50 equiv) and then BOP reagent
169.1, 170.4, 171.3; HRMS (FAB) calcd for M+ C58H88N4O11
Si2 1073.6066, obsd 1073.6127.
-
Fm oc-Hyp(OtBu )-Th r (OtBu )-DOP A(OTBS)2-Lys(ꢀ-Boc)-
OAll (41). Diethylamine (2 mL) was added to a solution of
tripeptide 38 (136 mg, 0.127 mmol, 1.00 equiv) in acetonitrile
(2 mL). The solution was stirred for 30 min at room temper-
ature under N2 and then concentrated. The residue was taken
up in acetonitrile (4 mL) and concentrated again. The residue
was dissolved in CH2Cl2 (4 mL), and Fmoc-Hyp(OtBu)-OH (40)