L.-X. Wang et al./Carbohydrate Research 306 (1998) 341±348
345
lactoside 3 (246 mg, 68%) and the 30,60-disulfo-ꢀ-
lactoside 4 (72 mg, 17%) as white powders after
lyophilization.
(0.282 mL, 2.0 mmol). The solution was cooled to
0 ꢀC and tetradecanoyl chloride (0.44 mL,
1.62 mmol) was added dropwise. The resulted mix-
ture was stirred for 3 h at 25 ꢀC. Methanol (0.2 mL)
was then added and the mixture was evaporated to
dryness. The crude product was puri®ed by column
chromatography (1:1 toluene±EtOAc) to give N-
tetradecanoyl-4-O-(hepta-O-acetyl-ꢀ-lactosyl)-3-
nitro-l-tyrosine ethyl ester (5) (702 mg, 80%).
Similarly, N-acetylation of 4-O-(hepta-O-acetyl-ꢀ-
lactosyl)-3-nitro-l-tyrosine ethyl ester with acetyl
chloride gave N-acetyl-4-O-(hepta-O-acetyl-ꢀ-lac-
tosyl)-3-nitro-l-tyrosine ethyl ester (6).
The 30-sulfate derivative 3. Rf 0.14 (65:25:4
1
CHCl3±MeOH±water); H NMR (Me2SO-d6+5%
D2O): ꢂ 7.610 (d, 1 H, J 8.8 Hz, H-5 in coumarin),
7.060 (dd, 1 H, J 2.1, 8.8 Hz, H-6 in coumarin),
6.975 (d, 1 H, J 2.1 Hz, H-8 in coumarin), 6.110 (s,
1 H, H-3 in coumarin), 5.209 (d, 1 H, J 7.6 Hz, H-
1), 4.629 (d, 1 H, J 7.8 Hz, H-10), 4.363 (dd, 1 H, J
3.5, 9.7 Hz, H-30), 4.325 (br d, 1 H, J 3.4 Hz, H-40),
4.076±3.670 (m, 10 H, other sugar protons), 2.345
(s, 3 H, Me in coumarin). Anal. Calcd for
C22H27NaO16S: C, 43.85; H, 4.52; S, 5.32. Found:
C, 43.70; H, 4.51; S, 5.20.
1
Compound 5. Rf 0.52 (1:2 toluene±EtOAc); H
NMR (CDCl3): ꢂ 7.536 (d, 1 H, J 2.0 Hz, aromatic
H), 7.307 (dd, 1 H, J 2.0, 8.6 Hz, aromatic H),
7.211 (d, 1 H, J 8.6 Hz, aromatic H), 6.011 (d, 1 H,
J 7.3 Hz, NH), 5.368 ( br d, 1 H, J 3.3 Hz, H-40),
5.282 (t, 1 H, J 8.2 Hz, H-3), 5.218±5.115 (m, 3 H,
H-1,2,20), 4.985 (dd, 1 H, J 3.3, 10.4 Hz, H-30),
4.846 (m, 1 H, CHNH), 4.579 (dd, 1 H, J 1.8,
12 Hz, H-6a), 4.547 (d, 1 H J 7.9 Hz, H-10), 4.212
(q, 2 H, J 7.1 Hz, OCH2CH3), 4.170±3.810 (m, 6 H,
4,5,50,6b,60a,60b), 3.203 (dd, 1 H, J 5.9, 14 Hz, 1/2
ArCH2), 3.109 (dd, 1 H, J 5.3, 14 Hz, 1/2 ArCH2),
2.215 (t, 2 H, J 7.2 Hz, CH2CO), 2.171, 2.125,
2.103, 2.081, 2.069, 2.064, and 1.983 (each s, each 3
H, 7 Ac), 1.308±1.257 (m, 25 H, 11 CH2 and
OCH2CH3), 0.884 (t, 3 H, J 6.6 Hz, CH3 in alkyl).
The 30,60-disulfate derivative 4. Rf 0.08 (65:25:4
1
CHCl3±MeOH±water); H NMR (Me2SO-d6+5%
D2O): ꢂ 7.700 (d, 1 H, J 8.8 Hz, H-5 in coumarin),
7.121 (dd, 1 H, J 2.2, 8.8 Hz, H-6 in coumarin),
7.071 (d, 1 H, J 2.2 Hz, H-8 in coumarin), 6.215 (s,
1 H, H-3 in coumarin), 5.264 (d, 1 H, J 7.8 Hz, H-
1), 4.651 (d, 1 H, J 7.9 Hz, H-10), 4.386 (dd, 1 H, J
3.2, 9.8 Hz, H-30), 4.373 (br d, 1 H, J 3.2 Hz, H-40),
4.257 (d, 2 H, J 6.0 Hz, H-60a,b), 4.072 (t, 1 H, J
6.0 Hz, H-50), 4.060±3.804 (m, 5 H, H-3,4,5,6a,b),
3.763±3.671 (m, 2 H, H-2,20), 2.417 (s, 3 H, Me in
coumarin). Anal. Calcd for C22H26Na2O19S2: C,
37.50; H, 3.72; S, 9.10. Found: C, 37.21; H, 4.05; S,
8.82.
N-Tetradecanoyl-4-O-(hepta-O-acetyl-b-lactosyl)-
3-nitro-l-tyrosine ethyl ester (5) and N-acetyl-4-O-
(hepta-O-acetyl-b-lactosyl)-3-nitro-l-tyrosine ethyl
ester (6). A two-phase solution of 3-nitro-l-tyro-
sine ethyl ester hydrochloride (291 mg, 1.0 mmol),
acetobromolactose (1.05 g, 1.5 mmol), and tetra-n-
1
Compound 6. Rf 0.32 (1:3 toluene±EtOAc); H
NMR (CDCl3): ꢂ 7.540 (d, 1 H, J 2.1 Hz, aromatic
H), 7.330 (dd, 1 H, J 2.1, 8.5 Hz, aromatic H),
7.219 (d, 1 H, J 8.5 Hz, aromatic H), 6.048 (d, 1 H,
J 7.1 Hz, NH), 5.370 (br d, 1 H, J 3.3 Hz, H-40),
5.283 (t, 1 H, J 8.2 Hz, H-3), 5.218±5.115 (m, 3 H,
H-1,2,20), 4.987 (dd, 1 H, J 3.3, 10.5 Hz, H-30),
4.842 (m, 1 H, CHNH), 4.590 (dd, 1 H, J 2.2,
12 Hz, H-6a), 4.549 (d, 1 H J 7.8 Hz, H-10), 4.220
(q, 2 H, J 7.1 Hz, OCH2CH3), 4.184±3.780 (m, 6 H,
4,5,50,6b,60a,60b), 3.210 (dd, 1 H, J 5.8, 14 Hz, 1/2
ArCH2), 3.120 (dd, 1 H, J 5.5, 14 Hz, 1/2 ArCH2),
2.171, 2.126, 2.104, 2.082, 2.073, 2.062, 2.037, and
1.984 (each s, each 3 H, 8 Ac), 1.291 (t, 3 H, J
7.1 Hz, OCH2CH3).
N-Tetradecanoyl-4-O-(b-lactosyl)-3-nitro-l-
tyrosine methyl ester (7) and N-acetyl-4-O-(b-
lactosyl)-3-nitro-l-tyrosine methyl ester (8). O-De-
acetylation of 5 (400 mg, 0.369 mmol) was carried
out with NaOMe±MeOH (10 mL, 10 mM) for 10 h
at 25 ꢀC, and the white precipitate formed was col-
lected by ®ltration to give the N-tetradecanoyl deriv-
ative 7 (250 mg, 87%). Similarly, de-O-acetylation
butylammonium
hydrogensulfate
(339 mg,
1.0 mmol) in aq. Na2CO3 (10 mL, 1 M) and CHCl3
(10 mL) was shaken for 5 h at 25 ꢀC. The two
layers were then separated and the aq. layer was
extracted with CHCl3 (2Â8 mL). The organic
layer and the extracts were combined and washed
with sat. NaHCO3 and water, dried (Na2SO4),
and ®ltered. The ®ltrate was evaporated and the
residue was subjected to column chromatography
(1:2 to 1:3 toluene±EtOAc) to give 4-O-(hepta-O-
acetyl-ꢀ-lactosyl)-3-nitro-l-tyrosine ethyl ester
(707 mg, 81%) as a syrup, Rf 0.13 (1:3 toluene±
EtOAc), which was used directly for the following
N-acylation reaction without further characteriza-
tion.
The free amino compound thus obtained was
dissolved in CH2Cl2 (15 mL) containing Et3N