Lipid A Derivatives
4798 – 4807
3,4,5-tri-O-benzyl-d-glucitol
(16):
Hydrazine
hydrate
(0.34 mL,
1H; H-1’), 4.77 (dd, J=9.8, 9.3 Hz, 1H; H-2), 4.83–4.35 (m, 10H; 5
CH2Ph), 4.44 (m, 1H; H-5), 4.37–4.32 (m, 2H; H-6a, H-6a’), 4.16 (q, J=
7.8 Hz, 1H; H-2’), 4.03–3.99 (m, 2H; H-3’, H-2), 3.91–3.86 (m, 2H; H-5’,
H-4’), 3.76 (m, 1H; H-6b), 3.68 (dd, J=9.1, 9.8 Hz, 1H; H-4), 3.58–3.55
(m, 2H; H-6b’, H-1a), 3.51–3.47 ppm (m, 2H; H-5, H-1b); 13C NMR
(75 MHz, CDCl3): d=174.2, 171.8 (NHCOCH3), 171.3, 171.2 (COCH3),
139.5–126.4 (Ph), 102.3 (CHPh), 101.7 (C-1’), 82.7, 79.1 (C-5), 78.8 (C-4’),
77.9 (C-3), 76.8 (C-4), 75.7–70.8 (5CH2Ph), 71.4 (C-3L), 71.1 (C-3’), 68.8
(C-6), 68.1 (C-6’), 66.8 (C-5’), 62.9, 54.6 (C-2’), 51.9 ppm (C-2); HRMS:
m/z: calcd for C130H204N2O16Na: 2073.6311; found: 2073.6309.
6.84 mmol) was added to a solution of 14 (0.389 g, 0.342 mmol) in ethanol
(15 mL). After being stirred at 908C for 15 h, the reaction mixture was
cooled and concentrated under reduced. The residue was coevaporated
from toluene (325 mL) after which it was purified by silica gel column
chromatography (35% gradient of ethyl acetate in hexanes) to afford an
amine (0.274 g, 0.283 mmol). DCC (0.05 g, 0.239 mmol) was added to a
solution of 15 (0.163 g, 0.239 mmol) in CH2Cl2 (5 mL) and stirred for
10 min, followed by the addition of the amine described above (0.193 g,
0.20 mmol) in CH2Cl2 (10 mL). The reaction mixture was stirred for 16 h
at room temperature. The solids were filtered off and the residue was
washed with CH2Cl2 (210 mL). The combined filtrate was concentrated
under reduced pressure and the residue was purified by silica gel column
chromatography (10% gradient of ethyl acetate in hexanes) to afford 16
as a white solid (0.23 g, 71%). Rf =0.57 (30% ethyl acetate in hexanes);
[a]2D3 =+21.38 (c=0.60 in CHCl3); 1H NMR (300 MHz, CDCl3): d=7.64–
7.14 (m, 30H; aromatic), 5.98 (d, 1H, J=5.8 Hz; NH), 5.53 (s, 1H;
>CHPh), 5.05 (m, 1H; H-3L), 4.71 (d, J=8.3 Hz, 1H; H-1’), 4.25 (dd,
J=5.8, 4.9 Hz, 1H; H-6a’), 4.17 (d, J=9.3 Hz, 1H; H-6a), 4.08 (t, J=
9.3 Hz, 1H; H-3’), 3.92 (m, 1H; H-5), 3.79–3.67 (m, 6H; H-6a, H-1a, H-
6b’, H-4, H-3, H-2), 3.56–3.50 (m, 3H; H-2’, H-4’, H-1b), 3.45 ppm (m,
1H; H-5); 13C NMR (75 MHz, CDCl3): d=174.4 (NHCOCH3), 171.5
(COCH3), 138.4–126.6 (Ph), 102.1 (CHPh), 101.5 (C-1’), 81.7 (C-4’), 79.8
(C-5), 79.5 (C-4), 78.4 (C-3), 75.1–72.4 (3CH2Ph), 71.5 (C-3’), 71.4 (C-
3L), (C-6), 70.4 (C-3), 68.8 (C-6’), 66.6 (C-5’), 63.9 (C-1, C-2), 59.4 ppm
6-O-{4’,6’-O-Benzylidene-3’-O-[(R)-3-benzyloxyhexadecanoyl]-2’-deoxy-
2’-[(R)-3-octacosanoyloxyhexadecan]amido-b-d-glucopyranosyl}-2-[(R)-
3-benzyloxyhexadecan]amido-3,4,5-tri-O-benzyl-d-gluconic acid (20):
Oxalyl chloride (12 mL, 0.136 mmol) was added to CH2Cl2 (1 mL) cooled
to À408C under an atmosphere of argon. DMSO (12 mL, 0.168 mmol)
was added and the mixture was stirred for 2 min at À408C. Compound
19 (36 mg, 17.47 mmol) in CH2Cl2 (1 mL) was added dropwise through a
syringe. Et3N ( 50mL, 0.288 mmol) was added after the reaction mixture
had been stirred for 30 min at À408C. The reaction was allowed to warm
to room temperature and stirred for 1 h. The reaction mixture was then
diluted with CH2Cl2 (15 mL), washed with saturated aqueous NH4Cl
solution, and then concentrated under reduced pressure. The residue was
dissolved in THF (0.5 mL), then NaClO2 (5 mg, 50 mmol), NaH2PO4
(3 mg, 2 mmol), and 2-methyl-2-butene (110 mL of 2m solution in THF) in
tBuOH (1 mL) and water (0.2 mL) were added. After stirring vigorously
for 3 h, the reaction mixture was concentrated under reduced pressure
and the residue was purified by silica gel column chromatography (1%
MeOH gradient in CH2Cl2) to afford 20 (26 mg, 74%). Rf =0.61 (10%
methanol in CH2Cl2); [a]2D3 =À9.348 (c=0.6 in CHCl3); 1H NMR
(500 MHz, CDCl3): d 7.41–7.18 (m, 30H, aromatic), 7.14 (d, J=8.8 Hz,
1H; NH), 6.36 (d, J=7.32 Hz, 1H; NH’), 5.46–5.42 (m, 2H; >CHPh, H-
1’), 5.26 (dd, J=9.3, 8.8 Hz, 1H; H-3’), 5.10 (m, 1H; H-3L), 4.52 (m, 1H;
H-1’), 4.77 (dd, J=9.8, 9.3 Hz, 1H; H-2), 4.83–4.35 (m, 10H; 5CH2Ph),
4.44 (m, 1H; H-5), 4.37–4.32 (m, 2H; H-6a, H-6a’), 4.16 (q, J=7.8 Hz,
1H; H-2’), 4.03–3.99 (m, 2H; H-3’, H-2), 3.91–3.86 (m, 2H; H-5’, H-4’),
3.76 (m, 1H; H-6b), 3.68 (dd, J=9.1, 9.8 Hz, 1H; H-4), 3.58–3.55 (m,
2H; H-6b’, H-1a), 3.51–3.47 ppm (m, 2H; H-5, H-1b); 13C NMR
(75 MHz, CDCl3): d=174.2, 171.8 (NHCOCH3), 171.3, 171.2 (COCH3),
139.5–126.4 (Ph), 102.3 (CHPh), 101.7 (C-1’), 82.7, 79.1 (C-5), 78.8 (C-4’),
77.9 (C-3), 76.8 (C-4), 75.7–70.8 (5CH2Ph), 71.4 (C-3L), 71.1 (C-3’), 68.8
(C-6), 68.1 (C-6’), 66.8 (C-5’), 62.9, 54.6 (C-2’), 51.9 ppm (C-2); HRMS:
m/z: calcd for C130H202N2O17Na: 2087.5119; found: 2087.5149.
(C-2’); HRMS: m/z: calcd for
1649.3158.
C100H148N4O12SiNa: 1649.3401; found:
1-O-(tert-Butyldiphenylsilyl)-6-O-{4’,6’-O-benzylidene-3’-O-[(R)-3-benzy-
loxyhexadecanoyl]-2’-deoxy-2’-[(R)-3-octacosanoyloxyhexadecan]amido-
b-d-glucopyranosyl}-2-[(R)-3-benzyloxyhexadecan]amido-3,4,5-tri-O-
benzyl-d-glucitol (18): A solution of 16 (210 mg, 0.123 mmol) in 1,3-pro-
panedithiol (0.25 mL, 2.46 mmol), pyridine (8.7 mL), and H2O (1.25 mL)
was stirred for 16 h at room temperature. The reaction mixture was con-
centrated in vacuo and the residue was coevaporated with toluene (2
5 mL) and ethanol (25 mL). The residue was purified by silica gel
column chromatography (2% gradient of methanol in CH2Cl2) to afford
the free amine as
a colorless syrup (189 mg, 95%). DCC (54 mg,
0.261 mmol) and DMAP (20 mg, 0.163 mmol) were added to a stirred
solution of 17 (89 mg, 0.244 mmol) in CH2Cl2 (10 mL). After stirring for
10 min, amine (131 mg, 0.081 mmol) in CH2Cl2 (1.5 mL) was added. The
reaction mixture was stirred for 16 h at room temperature, after which
the solids were filtered off and the residue was washed with CH2Cl2 (2
10 mL). The combined filtrates were concentrated in vacuo and the resi-
due was purified by silica gel column chromatography (3% gradient of
ethyl acetate in CH2Cl2) to afford 18 as a white solid (142 mg, 71%). Rf =
0.43 (20% ethyl acetate in hexanes); [a]2D3 =+12.58 (c=0.8 in CHCl3);
1H NMR (300 MHz, CDCl3): d=7.64–7.14 (m, 35H; aromatic), 6.23 (d,
J=8.3 Hz, 1H; NH), 5.78 (d, 1H; NH’), 5.39 (s, 1H; >CHPh), 5.38 (t,
J=9.3 Hz, 1H; H-3’), 4.98 (m, 1H; H-3L), 4.74 (1H; H-1’), 4.73–4.31 (m,
10H; 5CH2Ph), 4.29–4.26 (m, 2H; H-6a’, 2), 4.13 (d, J=9.8 Hz, 1H; H-
6a), 4.02 (d, J=7.8 Hz, 1H; H-3), 3.92–3.85 (m, 3H; H-5, H-6b, H-2’),
3.78 (m, 2H; H-4), 3.67–3.59 (m, 3H; H-6b’, H-4’, H-1b), 3.52 (dd, J=
9.8, 9.3 Hz, 1H; H-6a), 3.45 ppm (m, 1H; H-5); 13C NMR (75 MHz,
CDCl3): d=174.4, 172.8 (NHCOCH3), 171.5, 170.2 (COCH3), 138.4–126.6
(Ph), 102.1 (CHPh), 101.6 (C-1’), 82.0 (C-4’), 79.7 (C-5), 79.3 (C-4), 78.4
(C-3), 76.2–72.3 (5CH2Ph), 71.8 (C-3’), 71.4 (C-3L), 70.8 (C-6), 70.7 (C-
3), 68.9 (C-6’), 66.5 (C-5’), 62.6 (C-1), 55.4 (C-2), 51.5 ppm (C-2’);
HRMS: m/z: calcd for C146H222N2O16SiNa: 2312.1251; found: 2312.1257.
Debenzylation of compound 20: Pd/C (5 mg) was added to a solution of
hydroxy acid 20 (15 mg, 7.26 mmol) dissolved in THF/tBuOH (2 mL, 1:1).
The mixture was placed under an atmosphere of H2 and stirred for 24 h
at room temperature. The catalyst then was filtered off through a pad of
celite and subsequently washed with THF (23 mL) and CH2Cl2 (2
3 mL). The combined filtrates were concentrated under reduced pressure
and the residue was purified by size-exclusion column chromatography
with Sephadex LH-20 (iPrOH/ CH2Cl2 1:1) to afford a mixture of 3 and 4
(5 mg, 67%). Rf =0.41 (methanol/CH2Cl2/NH4OH 15:80:5); 1H NMR
(500 MHz, [D8]THF/MeOD 1:1): d=7.02 (d, 1H, J=8.8 Hz, NH), 6.84
(d, J=7.32 Hz, 1H; NH’), aminogluconate: 5.05 (t, J=10.4, 9.3 Hz, 1H;
H-3’), 4.71 (d, J=3.6; H-2), 4.54 (d, J=8.3 Hz, 1H; H-1’), 4.32 (1H; H-
3), 3.82 (1H; H-2’), 3.86 (1H; H-6a’), 3.73–3.70 (1H; H-6a, H-6b’), 3.55–
3.53 (2H; H-4’, H-6b), 3.54 (1H; H-4), 3.35–3.32 (1H; H-5, H-5’), amino-
gluconolactone: 5.01 (t, J=10.3, 9.3 Hz, 1H; H-3’), 4.66 (d, J=8.3 Hz,
1H; H-1’), 4.25 (1H; H-2, H-5), 3.89 (1H; H-6a), 3.86 (1H; H-2’, H-6a’),
3.69 (1H; H-6b), 3.55–3.54 (1H; H-4, H-4’), 3.32 (1H; H-5); HRMS:
aminogluconate: m/z: calcd for C88H168N2O17Na: 1548.2811; found:
1548.2816; aminogluconolactone: m/z: calcd for C88H166N2O16Na:
1530.2135; found: 1530.2786.
6-O-{4’,6’-O-Benzylidene-3’-O-[(R)-3-benzyloxyhexadecanoyl]-2’-deoxy-
2’-[(R)-3-octacosanoyloxyhexadecan]amido-b-d-glucopyranosyl}-2-[(R)-
3-benzyloxyhexadecan]amido-3,4,5-tri-O-benzyl-d-glucitol
(19):
1m
TBAF in THF (40 mL, 0.039 mmol) was added to a solution of 18 (76 mg,
0.033 mmol) in THF (2 mL). After the reaction mixture was stirred for
30 min, TLC analysis indicated completion of the reaction. The solvent
was evaporated in vacuo and the oily residue was subjected to purifica-
tion by silica gel column chromatography (10% gradient of ethyl acetate
in hexanes) to afford 19 as a fluffy white solid (62 mg, 91%). Rf =0.38
(30% ethyl acetate in hexanes); [a]2D5 =+5.08 (c=0.7 in CHCl3);
1H NMR (500 MHz, CDCl3): d=7.41–7.18 (m, 30H; aromatic), 6.38 (d,
Phenyl
2-azido-3,4-di-O-benzyl-6-O-(4’,6’-O-benzylidene-2’-deoxy-2’-
phthalimido-b-d-glucopyranosyl)-2-deoxy-1-thio-b-d-glucopyranoside
(21): A mixture of donor 5b (0.624 g, 1.16 mmol) and acceptor 7 (0.463 g,
0.97 mmol) and activated molecular sieves (4 A, 1.2 g) in CH2Cl2 (15 mL)
was stirred under an atmosphere of argon for 1 h. The mixture was
cooled (À358C) and NIS (0.26 g, 1.16 mmol) and TfOH (ꢀ10 mL) were
added. The reaction mixture was allowed to warm to À108C. After the
mixture had been stirring for 45 min, TLC analysis indicated completion
of the reaction. The reaction was quenched with pyridine (0.2 mL) and
J=8.8 Hz, 1H; NH), 6.23 (d, J=7.32 Hz, 1H; NH’), 5.43 (s, 1H;
CHPh), 5.26 (dd, J=9.3, 8.8 Hz, 1H; H-3’), 5.10 (m, 1H; H-3L), 4.52 (m,
>
Chem. Eur. J. 2004, 10, 4798 – 4807
ꢀ 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
4805