Zhu et al.
(m, 3H), 1.41 (s, 9H), 1.20 (m, 2H), 0.90 (m, 6H); 13C NMR
(CDCl3) δ 172.1, 171.2, 170.4, 170.3, 170.06, 169.97, 169.64,
169.58, 169.0, 155.6, 101.1, 83.7, 80.2, 77.2, 76.8, 76.1, 73.7,
71.0, 70.7, 70.4, 69.1, 66.6, 62.0, 60.8, 56.5, 53.2, 52.0, 37.6,
32.6, 29.6, 28.2, 25.0, 20.8, 20.72, 20.67, 20.55, 20.4, 15.4, 11.5;
stirred at room temperature until TLC indicated complete
consumption of the thiol, then diluted with EtOAc. The organic
phases were successively washed with saturated aqueous
NaHCO3 and brine, dried with MgSO4, then concentrated in
vacuo. The residue was purified by flash column chromatog-
raphy (petroleum ether/EtOAc, 1:1) to give 24 (125 mg, 92%)
as a white amorphous solid: TLC Rf 0.21 (petroleum ether/
EtOAc, 1.5:1); [R]D -12.5 (c 1.7 CHCl3); 1H NMR (CDCl3) δ
7.12 (d, J ) 7.9 Hz, 1H), 5.72 (d, J ) 7.2 Hz, 1H), 5.43 (d, J )
3.0 Hz, 1H), 5.22 (t, J ) 10.0 Hz, 1H), 5.03 (dd, J ) 10.0, 3.3
Hz, 1H), 4.56 (d, J ) 9.9 Hz, 1H), 4.50 (dd, J ) 8.4, 5.0 Hz,
1H), 4.39 (m, 1H), 4.27-4.00 (m, 3H), 3.71 (s, 3H), 3.09 (dd, J
) 14.4, 5.6 Hz, 1H), 2.88 (dd, J ) 14.4, 8.0 Hz, 1H), 2.15, 2.04,
2.01, 1.96 (each s, each 3H), 1.89 (m, 1H), 1.43 (s, 9H), 1.20
(m, 2H), 0.90 (m, 6H); 13C NMR (CDCl3) δ 171.6, 170.3, 170.2,
170.1, 169.9, 169.7, 155.6, 84.6, 80.3, 77.2, 75.1, 71.7, 67.3, 66.8,
61.7, 56.7, 53.8, 52.0, 37.8, 32.8, 29.7, 28.3, 25.1, 20.7, 20.5,
15.4, 11.5; MALDI-MS m/z 701.5 [M + Na+], 717.9 [M + K+].
Anal. Calcd for C29H46N2O14S (678.75): C, 51.32; H, 6.83; N,
4.13. Found: C, 51.36; H, 7.08; N, 4.05.
N-ter t-Bu toxyca r bon yl-S-(3,4,6-tr i-O-a cetyl-2-a zid o-2-
d e oxy-â-D-glu cop yr a n osyl)-L-h om ocyst e in yl-L-isole u -
cin e Meth yl Ester (26). To a solution of dipeptide 5 (84 mg,
0.23 mmol) in 3.2 mL of 10% Na2CO3 was added a solution of
bromide 25 (168 mg, 0.43 mmol) in EtOAc (3.2 mL) followed
by addition of TBAHS (316 mg, 0.93 mmol). The mixture was
vigorously stirred for 8 h at room temperature, then diluted
with EtOAc, washed successively with saturated aqueous
NaHCO3 and brine, dried over MgSO4, and concentrated. The
residue was purified by flash column chromatography (petro-
leum ether/EtOAc, 1:1) to afford 26 (15 mg, 10%), which was
redissolved in a small amount of dioxane and lyophilized to
give 26 as a white solid: TLC Rf 0.30 (petroleum ether/EtOAc,
1:1); [R]D +39.9 (c 1.0 CHCl3); 1H NMR (CDCl3) δ 6.85 (d, J )
7.9 Hz, 1H), 5.58 (d, J ) 8.2 Hz, 1H), 5.15 (d, J ) 10.6 Hz,
1H), 5.09 (dd, J ) 10.2, 8.3 Hz, 1H), 4.63 (d, J ) 6.9 Hz, 1H),
4.51 (dd, J ) 8.5, 5.0 Hz, 1H), 4.26 (t, J ) 7.8 Hz, 1H), 4.18
(dd, J ) 12.2, 4.4 Hz, 1H), 4.03 (dd, J ) 12.2, 2.2 Hz, 1H),
3.96 (m, 1H), 3.71 (s, 4H), 2.83 (m, 2H), 2.11, 2.03, 1.94 (4s,
12H), 1.90 (m, 3H), 1.40 (s, 9H), 1.20 (m, 2H), 0.88 (m, 6H);
13C NMR (CDCl3) δ 172.3, 171.3, 170.9, 170.6, 169.3, 155.4,
80.2, 77.2, 74.8, 74.7, 71.2, 69.1, 62.0, 56.7, 52.7, 52.1, 45.0,
37.4, 32.3, 28.3, 27.7, 25.1, 20.9, 20.7, 20.5, 15.6, 11.5. Anal.
Calcd for C28H45N5O12S (675.75): C, 49.77; H, 6.71; N, 10.36.
Found: C, 49.28; H, 7.03; N, 10.05.
MALDI-MS m/z 1004.5 [M + Na+]. Anal. Calcd for C42H64
-
N2O22S‚0.5C7H8 (1027.09): C, 53.21; H, 6.67; N, 2.73. Found:
C, 53.43; H, 6.90; N, 2.67.
N-ter t-Bu toxyca r bon yl-S-(m eth yl 5-a ceta m id o-4,7,8,9-
tetr a -O-a cetyl-3,5-d id eoxy-D-glycer o-r-D-ga la cto-2-n on u -
lop yr a n osylon a te)-L-h om ocystein yl-L-isoleu cin e Meth yl
Ester (21). To a solution of dipeptide 5 (86 mg, 0.24 mmol) in
3.3 mL of 10% Na2CO3 was added a solution of freshly
prepared â-acetochloroneuraminic acid 17 (160 mg, 0.31 mmol)
in EtOAc (3.3 mL). To this mixture was added TBAHS (338
mg, 0.99 mmol). The mixture was stirred vigorously at room
temperature for 8 h and next diluted with EtOAc, washed
successively with saturated aqueous NaHCO3 and brine. The
organic layer was dried with MgSO4 and evaporated to a
residue, which was purified by flash column chromatography
(petroleum ether/EtOAc, 1:2 f 1:4) to afford 21 (150 mg, 76%)
as a white amorphous solid: TLC Rf 0.10 (petroleum ether/
EtOAc, 1:1.5); [R]D +11.8 (c 1.3 CHCl3); 1H NMR (CDCl3) δ
7.03 (d, J ) 8.4 Hz, 1H), 5.84 (d, J ) 8.1 Hz, 1H), 5.40 (m,
1H), 5.31 (dd, J ) 9.6, 1.4 Hz, 1H), 5.18 (d, J ) 9.9 Hz, 1H),
4.85 (m, 1H), 4.53 (dd, J ) 8.6, 5.3 Hz, 1H), 4.24 (dd, J ) 12.2,
1.6 Hz, 1H), 4.02 (m, 2H), 3.80 (m, 1H), 3.77 (s, 3H), 3.68 (s,
3H), 2.66 (m, 3H), 2.20, 2.11, 2.03, 2.00, 1.85 (each s, each 3H),
1.42 (s, 9H), 0.87 (m, 6H); 13C NMR (CDCl3) δ 172.0, 171.3,
171.0, 170.9, 170.2, 170.1, 168.7, 155.7, 83.2, 79.8, 77.2, 73.8,
69.5, 68.1, 66.8, 62.1, 56.5, 54.3, 53.0, 51.9, 49.5, 38.0, 37.7,
33.4, 29.7, 28.3, 25.4, 25.1, 23.2, 21.3, 20.8, 20.7, 15.4, 11.5;
MALDI-MS m/z 859.1 [M + Na+], 875.4 [M + K+]. Anal. Calcd
for C36H57N3O17S (835.91): C, 51.73; H, 6.87; N, 5.03. Found:
C, 51.32; H, 6.90; N, 4.83.
Boc-Cys-Ile-OMe (22). 22 was prepared from commercially
available N-Boc protected cystine in two steps as described
for Boc-Hcy-Ile-OMe 5, and it was used immediately after
purification.
N-ter t-Bu toxycar bon yl-S-(2,3,4,6-tetr a-O-acetyl-â-D-glu -
cop yr a n osyl)-L-cystein yl-L-isoleu cin e Meth yl Ester (23).
To a solution of dipeptide 22 (51 mg, 0.15 mmol) in 2 mL of
10% Na2CO3 was added a solution of bromide 11 (112 mg, 0.27
mmol) in EtOAc (2 mL). TBAHS (190 mg, 0.56 mmol) was then
added to the above mixture. The reaction mixture was vigor-
ously stirred at room temperature until TLC indicated com-
plete consumption of the thiol, then diluted with EtOAc. The
mixture was partitioned between EtOAc and H2O, and the
organic layer was washed with saturated aqueous NaHCO3
and brine, then dried over MgSO4 and concentrated. Flash
column chromatography (petroleum ether/EtOAc, 1:1) of the
residue gave 23 (93 mg, 94%) as a white amorphous solid: TLC
Rf 0.20 (petroleum ether/EtOAc, 1.5:1); [R]D -13.5 (c 1.0
N-ter t-Bu toxyca r bon yl-S-(3,4,6-tr i-O-a cetyl-2-a zid o-2-
d eoxy-â-D-glu cop yr a n osyl)-L-h om ocyst ein yl-L-a la n in e
Am id e (27). To a solution of dipeptide 4 (70 mg, 0.23 mmol)
in 3.2 mL of 10% Na2CO3 was added a solution of bromide 25
(193 mg, 0.49 mmol) in EtOAc (3.2 mL) followed by addition
of TBAHS (316 mg, 0.93 mmol). The mixture was vigorously
stirred for 8 h at room temperature, then diluted with EtOAc,
washed successively with saturated aqueous NaHCO3 and
brine, dried over MgSO4, and concentrated. The residue was
purified by flash column chromatography (CH2Cl2/MeOH, 40:1
f 25:1) to afford 27 (43 mg, 30%), which was lyophilized with
dioxane to yield 27 as a white solid: TLC Rf 0.21 (EtOAc);
1
CHCl3); H NMR (CDCl3) δ 7.10 (d, J ) 7.9 Hz, 1H), 5.65 (d,
J ) 7.1 Hz, 1H), 5.23 (t, J ) 9.3 Hz, 1H), 5.05 (t, J ) 10.0 Hz,
1H), 5.01 (t, J ) 9.3 Hz, 1H), 4.63 (d, J ) 10.0 Hz, 1H), 4.50
(dd, J ) 8.4, 5.1 Hz, 1H), 4.43 (m, 1H), 4.26 (dd, J ) 12.3, 2.3
Hz, 1H), 4.13 (dd, J ) 12.3, 6.2 Hz, 1H), 3.86 (m, 1H), 3.72 (s,
3H), 3.06 (dd, J ) 14.3, 5.4 Hz, 1H), 2.85 (dd, J ) 14.3, 7.9
Hz, 1H), 2.04, 2.03, 2.02, 1.99 (each s, each 3H), 1.90 (m, 1H),
1.43 (s, 9H), 1.20 (m, 2H), 0.91 (m, 6H); 13C NMR (CDCl3) δ
171.6, 170.5, 170.1, 170.0, 169.5, 155.3, 84.7, 80.3, 77.2, 76.2,
73.6, 69.6, 68.4, 62.3, 56.8, 53.9, 52.0, 37.8, 33.5, 28.3, 25.1,
20.6, 20.5, 15.4, 11.5; MALDI-MS m/z 701.6 [M + Na+]. Anal.
Calcd for C29H46N2O14S (678.75): C, 51.32; H, 6.83; N, 4.12.
Found: C, 51.11; H, 6.87; N, 3.85.
1
[R]D -24.0 (c 1.1 CHCl3); H NMR (CDCl3) δ 6.84 (d, J ) 7.5
Hz, 1H), 6.25 (br s, 1H), 5.47 (br s, 1H), 5.31 (d, J ) 5.9 Hz,
1H), 5.08 (t, J ) 9.4 Hz, 1H), 5.01 (t, J ) 9.4 Hz, 1H), 4.45 (m,
2H), 4.26 (m, 1H), 4.20 (d, J ) 3.4 Hz, 2H), 3.71 (m, 1H), 3.51
(t, J ) 9.6 Hz, 1H), 2.81 (t, J ) 7.3 Hz, 2H), 2.10 (m, 2H),
2.08, 2.07, 2.01 (3s, 9H), 1.43 (s, 9H), 1.39 (d, J ) 7.1 Hz, 3H);
13C NMR (CDCl3) δ 174.0, 171.4, 170.8, 169.9, 169.6, 156.4,
84.8, 80.7, 75.9, 74.5, 68.2, 63.6, 61.9, 53.8, 48.6, 32.9, 28.3,
27.6, 20.8, 20.64, 20.56, 17.6; MALDI-MS m/z 641.5 [M + Na+],
657.6 [M + K+]. Anal. Calcd for C24H38N6O11S‚C4H8O2
(706.77): C, 47.58; H, 6.56; N, 11.89. Found: C, 47.66; H, 6.77;
N, 11.92.
N-ter t-Bu toxyca r bon yl-S-(2,3,4,6-tetr a -O-a cetyl-â-D-ga -
la ct op yr a n osyl)-L-cyst ein yl-L-isoleu cin e Met h yl E st er
(24). To a solution of dipeptide 22 (70 mg, 0.20 mmol) in 3 mL
of 10% Na2CO3 was added a solution of bromide 16 (153 mg,
0.37 mmol) in EtOAc (3 mL) followed by addition of TBAHS
(260 mg, 0.77 mmol). The resulting mixture was vigorously
N-ter t-Bu toxyca r bon yl-S-[3,4,6-tr i-O-a cetyl-2-d eoxy-2-
(2,2,2-t r ich lor oet h yloxyca r b on yla m in o)-â-D-glu cop yr a -
n osyl]-L-cystein yl-L-isoleu cin e Meth yl Ester (29). To a
5648 J . Org. Chem., Vol. 68, No. 14, 2003