Synthesis and antiviral evaluation of 6'-acylamido-6'-deoxy-α-d- mannoglycerolipids

Article abstract of DOI:10.1016/j.carres.2013.08.010

Eight new aminomannoglycerolipids (2a-h) with linear, branched, or aromatic acyl chains were synthesized and evaluated for their anti-influenza A virus (IAV) activity. By comparing six mannosyl donors with different protecting and leaving groups, the critical glycosylation reaction employed mannosyl trichloroacetimidate with 2-O-benzoyl protecting group as the donor to give the glycoside with absolute α-anomeric selectivity. The bioactivity results showed that the branched compound 2g could effectively inhibit IAV multiplication in MDCK cells with IC₅₀ 69.9 μM.

Full text of DOI:10.1016/j.carres.2013.08.010

Carbohydrate Research 381 (2013) 74–82
Contents lists available at ScienceDirect
Carbohydrate Research
journal homepage: www.elsevier.com/locate/carres
Synthesis and antiviral evaluation of 60-acylamido-60-deoxy-
a-D-
mannoglycerolipids
⇑
Jun Zhang , Yihua Sun , Wei Wang, Xiaoshuang Zhang, Chunxia Li , Huashi Guan
Key Laboratory of Marine Drugs, Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 30 May 2013
Received in revised form 12 July 2013
Accepted 14 August 2013
Available online 23 August 2013
Eight new aminomannoglycerolipids (2a–h) with linear, branched, or aromatic acyl chains were synthe-
sized and evaluated for their anti-influenza A virus (IAV) activity. By comparing six mannosyl donors with
different protecting and leaving groups, the critical glycosylation reaction employed mannosyl trichloro-
acetimidate with 2-O-benzoyl protecting group as the donor to give the glycoside with absolute
meric selectivity. The bioactivity results showed that the branched compound 2g could effectively inhibit
IAV multiplication in MDCK cells with IC50 69.9 M.
a-ano-
l
Keywords:
Ó 2013 Elsevier Ltd. All rights reserved.
Aminoglycoglycerolipid
Influenza A virus
Glycosylation
a-Anomeric selectivity
1. Introduction
for antiviral drugs, we found some 60-acylamido-60-deoxy-
a-D-gly-
coglycerolipids showed anti-influenza A virus (IAV) activity during
the bioactivity screening (data not shown), including the aminom-
annoglycerolipids. Different acyl derivatives of mannoglycerolipids
could be found in different bacteria and served as precursors for
the formation of complex membrane components.23,24 There is
no report on chemically synthesizing this type of glycoglyceroli-
pids and activity evaluation as yet.
Glycoglycerolipids are the predominant lipids in chloroplasts of
plants and eukaryotic algae, also in cyanobacteria.1 Various glyco-
glycerolipids have been isolated from green, red, and brown algae,
such as monogalactosyldiacylglycerol (MGDG), digalactosyldiacyl-
glycerol (DGDG) and sulfoquinovosyldiacylglycerol (SQDG). These
glycolipids are reported to exhibit many biological activities.2–6
In 2005, a kind of aminoglycoglycerolipid, 1,2-dipalmitoyl-3-
In this paper, we reported the strategy for the synthesis of linear
(medium-long length, from C6–C18), branched, or aromatic acyl
(N-palmitoyl-60-amino-60-deoxy-
a-D-glucopyranosyl)-sn-glycerol
(1, Fig. 1), which was isolated from an algal species, showed en-
zyme Myt1-kinase inhibition.7 By far only eight natural aminogly-
coglycerolipids have been obtained but attracted much attention
because of their diverse bioactivities, such as anti-bacterial, anti-
tumor, anti-viral etc.8–12 Due to the unique structure of such glyco-
glycerolipids, Schmidt and co-workers,13 Colombo et al.14 and our
group15–17 had completed the synthesis of natural product 1 or its
aminoglycoglycerolipid analogues for biological activity assay.
Influenza A virus (IAV) has been the cause of at least three pan-
demics in the last century, the most severe leading to more than 40
million fatalities in 1918–1919.18 Current anti-IAV drugs are direc-
ted against neuraminidase (NA; zanamivir, and oseltamivir) and
the M2 protein (adamantanes).19,20 Despite these successes, new
antiviral agents are urgently needed, due to the drug efficacy, resis-
tance, toxicity, and cost.21 Many glycoglycerolipids isolated from
algae possess potential anti-viral bioactivities.22 In our research
chains linking to 3-O-a-D
-(60-amino-60-deoxy-mannopyranosyl)-
sn-glycerol (1,2,60-positions, 2a–h, Fig. 1) and also evaluated their
inhibitory activity of influenza A virus (IAV) multiplication in
MDCK cells. The relationship between the structural changes of
the lipophilic chain on the aminomannosylglycerols and inhibitory
activities was discussed.
2. Results and discussion
2.1. Chemistry
Our synthesis plan was outlined in Scheme 1. A properly pro-
tected glycosyl glycerol derivative 4 was envisaged as an important
intermediate. To get this intermediate, we assume that an appro-
priate glycosyl donor 5 could couple with (S)-isopropylideneglyc-
erol 6 to construct the
It is well established that 1,2-trans-glycosides (b-glycosides for
-glucose, -galactose, -glycoside for -mannose) can be conve-
a-glycosidic bond.
D
D
a
D
⇑
Corresponding author. Tel.: +86 532 82032030; fax: +86 532 82033054.
E-mail address: lchunxia@ouc.edu.cn (C. Li).
niently prepared with the assistance of a neighboring participating
group, generally an acyl moiety such as O-acetyl (Ac), O-benzoyl
These authors contributed equally to this work.
0008-6215/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.carres.2013.08.010

J. Zhang et al. / Carbohydrate Research 381 (2013) 74–82
75
a: R = hexanoyl
NHR
OH
NHR
O
b: R = octanoyl
c: R = lauroyl
O
HO
HO
HO
d: R = myristoyl
e: R = palmitoyl
f: R = stearoyl
HO
OR
OR
OH
O
O
OR
OR
g: R = isovaleryl
h: R = hydrocinnamoyl
1 R = palmitoyl
2
Figure 1. Structures of natural aminoglycoglycerolipid 1 and its analogues 2a–h.
N3
5
O
P
LG
NHR
OH
O
NH2
N3
OBn
O
O
+
HO
HO
BnO
P
BnO
O
OH
OR
O
OH
O
O
OR
O
O
HO
O
4
2a-h
3
6
Scheme 1. Retrosynthetic analysis.
(Bz), Nphthalimido (Phth), etc.25–27 In order to constitute the
-mannosides 2a–h, mannosyl donors 5a, 5b, 5c, and 5d (Fig. 2)
(S)-isopropylideneglycerol from racemization (entry 1).15,29 Disap-
pointedly, compound 5a did not show any change for 48 h and the
desired product 4-1 was not detected. We assumed that the elec-
tron-withdrawing ability of acetyl groups strongly decreased the
nucleophilicity of the leaving group. It was indicated that another
disarmed thioglycosyl donor 5c with the benzoyl protecting group
would have a similar result and we abandoned the study on this
donor. Then, the relatively active Schmidt donor 5b was chosen
to conduct the coupling reaction. However, the hydrolysis product
of 5b instead of the hypothetical product 4-1 in the reaction was
obtained in all cases, even if the temperature was lowered to
ꢁ78 °C (entry 2). It indicated that the formation of an acyloxonium
(dioxalenium) intermediate by attacking from the adjacent car-
bonyl oxygen during the reaction was unstable and easily hydro-
lyzed to the side product.
a
were prepared with different leaving groups (thioglycosides and
trichloroacetimidate) and acyl groups (Ac, Bz) at the C-2 position.
The commonly accepted belief was that benzylated derivatives
were more reactive than their benzoylated counterparts.28 So as
a supplement, we also synthesized armed mannosyl donors 5e
and 5f, bearing a non-participating group (O-benzyl, Bn) at C-2.
A brilliant advantage of thioglycoside was that it can be easily
transformed into other glycosyl donors, such as trichloroacetimi-
date. Therefore, six different mannosyl donors can be obtained in
a fluent synthetic way (Scheme 2). Firstly, compound 8 was pre-
pared from D-mannose 7 and the primary alcohol was selectively
tosylated and further reacted with acetic anhydride in one-pot.
Then the tosyl group was substituted by an azide group to produce
9 by reaction with sodium azide in DMF. Thioglycoside 5a was syn-
thesized as the first donor from peracetate 9 using thiocresol and
BF3ꢀOEt2 in CH2Cl2. Removal of acetyl at anomeric position of 9
using NH2NH2ꢀHOAc in DMF, followed by treatment with CCl3CN
and DBU afforded trichloroacetimidate 5b as the second mannosyl
donor. Removal of the acetates of 5a by Zemplen deacetylation
yielded a tetrol, which was then reacted with benzoyl chloride
and benzyl bromide respectively to yield benzoylated thioglyco-
side 5c and benzylated thioglycoside 5e. The Schmidt donors 5d
and 5f were obtained from thioglycoside 5c and 5e following a
similar procedure for the synthesis of 5b.
Then we turned our attention to the armed mannosyl donors 5e
and 5f with the protecting group of benzyl to carry out this reac-
tion. The glycosylation reactions for donor 5e were performed in
CH2Cl2 and Et2O respectively in the presence of DTBMP (entry 3,
4). The products 4-3 and 40-3 were accessed in 84–86% yield with
the ratio of
a:b = 1:1 (a isomer: JC1–H1 = 169 Hz; b isomer: JC1–
H1 = 155 Hz). The stereoselectivity was not improved even if the
reaction time was prolonged to 48 h with the solvent of Et2O. Then
the trichloroacetimidate donor 5f was used in the glycosylation
reaction in the solvent of Et2O. This acid-catalyzed reaction pro-
ceeded quickly without racemization of the (S)-isopropylidene-
glycerol residue on 1H NMR and gave almost the same results as
entry 4 (entry 5). This results indeed supported that ether-group
(Bn) improved the activity of glycosyl donor but was not favored
for the 1,2-trans configuration construction. Although the isomer
Subsequently, the glycosylation reactions using the six different
mannosyl donors were explored (Table 1). The first attempt was
carried out using the disarmed thioglycosyl donor 5a in CH2Cl2
with NIS-TMSOTf, meanwhile, DTBMP was added to prevent
N3
N3
N3 OAc
O
OBz
O
OBn
O
AcO
AcO
BzO
BzO
BnO
BnO
STol
STol
5a
5e
5c
STol
NH
N3
N3
N3
OBn
O
OBz
O
OAc
O
AcO
AcO
BnO
BnO
BzO
BzO
NH
CCl3
NH
CCl3
O
CCl3
5d
5f
O
O
5b
Figure 2. Structures of different mannosyl donors.

76
J. Zhang et al. / Carbohydrate Research 381 (2013) 74–82
OTs
OH
OH
N3
N
N
OAc
O
3OAc
O
3 OAc
OAc
O
O
O
a
c
b
d
OH
AcO
AcO
AcO
AcO
AcO
AcO
HO
HO
AcO
AcO
NH
O CCl3
OH
7
OAc
10
9
OAc
8
5b
e
N3
N3
OBz
N3
N3
N3
OAc
O
OBn
O
OBz
O
OBn
f
h
O
g
O
e
BnO
BnO
BzO
BzO
BzO
BzO
BnO
BnO
AcO
AcO
NH
CCl3
NH
CCl3
5f
STol
STol
STol
5a
5e
5d
5c
O
O
Scheme 2. Reagents and conditions: (a) Py, TsCl, 0 °C, then Ac2O, 0 °C; (b) NaN3, DMF, 65 °C, 46% over two steps; (c) NH2NH2ꢀHOAc, DMF, 89%; (d) DBU, CNCCl3, CH2Cl2, 84%;
(e) p-thiocresol, BF3ꢀOEt2, CH2Cl2, 78%; (f) MeONa, MeOH, then BzCl, CH2Cl2, Et3N, DMAP, 88% over two steps; (g) MeONa, MeOH, then BnBr, NaH, DMF, 92%, over two steps;
(h) NBS, acetone/water (9:1), then DBU, CNCCl3, CH2Cl2, 91% for 5d, 95% for 5f.
Table 1
Glycosylation of different mannosyl donors with (S)-isopropylideneglycerol
N3
OR
O
RO
RO
N3
STol
N3
OR
O
OR
5a: R = Ac
5c: R = Bz
5e: R = Bn
O
O
O
HO
O
RO
RO
RO
RO
O
+
O
O
promotors
N3
OR
O
O
O
RO
RO
NH
O
4'-1: R = Ac
4'-2: R = Bz
4'-3: R = Bn
4-1: R = Ac
4-2: R = Bz
4-3: R = Bn
CCl3
5b: R = Ac
5d: R = Bz
5f: R = Bn
Entrya
Donor
Solvent
Promoter
Temp
Time (h)
Yield (%)
Ratiob
(a:b)
d
1c
2c
3
4
5
5a
5b
5e
5e
5f
CH2Cl2
CH2Cl2
CH2Cl2
Et2O
Et2O
CH2Cl2
NIS–TMSOTf
TMSOTf
rt
48
48
8
48
0.5
0.5
0
0
86
84
87
83
—
—
1:1
1:1
1:1
1:0
e
ꢁ78 °C
d
d
NIS–TMSOTf
NIS–TMSOTf
rt
rt
0 °C
0 °C
e
TMSOTf
TMSOTf
e
6
5d
a
b
c
All reactions were carried out in dry solvent with 1.2 equiv acceptor.
All products were determined by 600 MHz 1H NMR.
No desired product was obtained in 48 h.
1.5 equiv NIS, 0.1 equiv TMSOTf and 0.2 equiv DTBMP were added.
0.1 equiv TMSOTf was added.
d
e
mixture could be separated easily through the silica column chro-
it is difficult to control the stereochemistry of the products some-
times. The contributing factors to the stereoselectivity were com-
plex, including the configuration of the glycosyl donors,31–35 the
structure of the leaving groups,36 the reaction conditions,37 the
reactivity of the glycosyl acceptors,38,39 and the protecting groups
on the donors.40–44 By comparing six glycosyl donors with different
protecting groups and leaving groups in the glycosylation reac-
tions, our study indicated that the benzoyl groups and trichloro-
matography, the yield of the
satisfactory.
a-isomer-product was still not
Finally we employed the benzoyl protected trichloroacetimi-
date donor 5d to perform this reaction, which resulted in the for-
mation of the desired product 4-2 as a single isomer in 83% yield
(entry 6). The high stereoselectivity and lack of hydrolysis product
from 5d served as evidence that the neighboring effect occurred
when the benzoyl protecting group was located at the C-2 position
of the glycosyl donor and the benzoyl group enabled the more sta-
ble trichloroacetimidate donor than the acetyl group.
It was noteworthy that the benzoyl group seemed incompatible
with di-O-acyl groups of glycerol in 2a–h.30 Benzyl group seemed
more convenient in this study at the stage of global deprotection.
Thus 4-2 was converted to 4-3 by two steps with 80% yield
(Scheme 3). The three-step yield of obtaining compound 4-3 of
acetimidate played critical roles in improving the
the mannosyl donor.
a-selectivity of
With the key intermediate 4-3 in hand, we accessed the final
compounds through four steps (Scheme 3). Alcoholysis of the iso-
propylidene protecting group with TsOH in methanol provided 11.
Reduction of the azido group by Staudinger reaction yielded the
appropriate amino derivative 3. Introduction of acyl chains on
C1, C2, and C60–NH2 of 3 by condensation with the corresponding
acyl chloride in the presence of 4-N,N-dimethylaminopyridine
(DMAP) gave 12a–h in 70–90% yield. Then removal of the benzyl
by hydrogenolysis using H2/Pd(OH)2 generated the final com-
pounds 2a–h. The structures of the synthetic compounds were
identified by 1H, 13C NMR and HR-ESI-MS, and the purity of the
the
a-isomer from donor 5d was much higher than 5e and 5f. So
considering the chemical and stereochemical yield of the glycosyl-
ation reaction with six different mannosyl donors, 5d was the
optimal candidate for this glycosylation reaction. Generally,
glycosylation is the critical step for the glycoside synthesis because

J. Zhang et al. / Carbohydrate Research 381 (2013) 74–82
77
N3
N3
N3
OBz
O
OBn
O
OBn
O
a
BzO
BzO
BnO
BnO
c
BnO
BnO
b
O
O
OH
O
O
O
O
O
OH
4-2
4-3
11
a: R = hexanoyl
b: R = octanoyl
c: R = lauroyl
NH2
NHR
OH
NHR
OBn
OBn
O
O
O
e
d
BnO
BnO
HO
HO
BnO
BnO
d: R = myristoyl
e : R = palmitoyl
f: R = stearoyl
OH
OR
OR
O
OH
O
OR
O
OR
2
g: R = isovaleryl
h: R = hydrocinnamoyl
3
12
Scheme 3. Reagents and conditions: (a) MeONa, MeOH, then BnBr, NaH, DMF, 80% over two steps; (b) TsOH, MeOH; (c) PPh3, THF/H2O, 95% over two steps; (d) acyl chloride,
Py, DMAP, 70–90%; (e) Pd(OH)2/C, H2, THF/i-PrOH(9:1), 80–94%.
Table 2
The inhibitory effect of aminomannoglycerolipid analogues on IAV replication in vitro
a
b
a
b
Compound
Virus inhibition%
IC50
(l
M)
Compound
Virus inhibition%
IC50
(lM)
2a
2b
2c
2d
2e
0
0
24.0
83.4
48.0
—
—
—
n.d.
—
2f
2g
2h
Ribavirin
31.2
64.5
0
—
69.9
—
74.5
87.2
a
Performed at a concentration of 50
‘—‘ = undetected; ‘n.d.’ = no dose-dependent manner was tested.
l
M.
b
target compounds was higher than 95% (HPLC, RP-18 column, CH3-
CN–H2O = 1:1).
4. Experimental
4.1. Chemical procedures
4.1.1. General methods
Solvents were purified in a conventional manner. Thin layer
chromatography (TLC) was performed on precoated HSGF254
plates (Yantai, China). Flash column chromatography was per-
formed on silica gel (200–300 mesh, Qingdao, China). Optical rota-
2.2. Biological evaluation
The anti-influenza A virus activity of aminomannoglycerolipid
analogues with different acyl chains (2a–h) was evaluated by the
cytopathic effects (CPE) inhibition assay.45 As shown in Table 2,
compound 2d, which contained three myristoyl (C14:0) acyl
chains, displayed the best virus inhibition at 50 lM among the
tion was determined with
a Perkin–Elmer Model 241 MC
polarimeter. 1H NMR and 13C NMR spectra were taken on a JEOL
JNM-ECP 600 MHz and an Agilent 500 MHz DD2 spectrometers
with tetramethylsilane (Me4Si) as the internal standard, and chem-
ical shifts were recorded as d values. Mass spectra were recorded
on a Global Q-TOF mass spectrometer and IonSpec 4.7 Tesla FTMS
(MALDI/DHB).
aminomannoglycerolipid anologues bearing medium-long length
linear fatty acids (2a–f). Besides, compounds 2g bearing branched
fatty acyl chains exhibited similar inhibitory activity with the con-
trol of ribavirin, whereas compound 2h with aromatic acyl chains
showed no activity. Compounds 2d and 2g which showed good
activity in the preliminary anti-viral screening were further tested
for virus inhibition at the concentration of 12.5–100 lM. Viral rep-
lication in MDCK cells was dose-dependently inhibited by 2g and
4.1.2. 6-Azido-1,2,3,4-tetra-O-acetyl-6-deoxy-a-D-mannopy-
the concentration required for 2g to reduce the CPE of the virus
ranose (9)
by 50% (IC50) was 69.9 lM. These results indicated that both the
D
-Mannose 7 (4.5 g, 25.0 mmol) was dissolved in dry pyridine
type and the length of the acids linking the aminomannosylglyce-
rols could influence the inhibitory effect on IAV multiplication in
MDCK cells.
(60 mL) and cooled to 0 °C. Then tosyl chloride (5.3 g, 27.5 mmol)
was slowly added. The reaction was kept stirring at 0 °C overnight.
Subsequently to this solution was added dropwise Ac2O (14.2 mL,
150 mmol). After stirring for 2 h the solvent was removed under
reduced pressure, then the residue was dissolved in 200 mL CH2Cl2
and washed sequentially with aq HCl (0.1 M, 100 mL ꢂ 2), satu-
rated NaHCO3 solution (100 mL ꢂ 2) and brine(100 mL ꢂ 2). The
organic phase was dried and concentrated to get crude 8 as a syrup.
To the solution of crude 8 in dry DMF (80 mL) was added NaN3
(4.9 g, 75.0 mmol). The reaction mixture was stirred at 60 °C for
10 h, then cooled to rt. The mixture was diluted with water
(100 mL) and extracted with CH2Cl2 (80 mL ꢂ 3). All of the organic
extracts were combined, and then dried and concentrated under
vacuum to give a residue. The residue was purified by silica gel
chromatography (EtOAc–petroleum ether 1:4) to give 9 (4.2 g, over
3. Conclusion
In conclusion, the analogues of aminomannoglycerolipid were
synthesized in an efficient way with high stereoselectivity (a only)
by employing 5d as the glycosyl donor. Our research demonstrated
that the chemical and stereochemical yield in the glycosylation
reaction was directly associated with the protecting group and
leaving group of the donors. The present synthesis provided vari-
ous acyl derivatives and the results of anti-viral assay indicated
that the type and the length of the acids linking the aminomanno-
glycerolipids could influence the inhibitory activity of IAV multipli-
cation in MDCK cells, especially compound 2g with branched acyl
chains showed good inhibitory effect on IAV multiplication
two steps 46%) as a white solid; ½a D22
ꢃ
+57.3 (c 1.1, CHCl3); 1H NMR
(600 MHz, CDCl3): d 6.10 (d, 1H, J = 2.2 Hz, H-1), 5.34–5.36 (m, 2H,
H-3, H-4), 5.26 (t, 1H, J = 2.2 Hz, H-2), 4.00 (ddd, J = 9.3, 5.8, 3.1 Hz,
(IC50 = 69.9 lM).

78
J. Zhang et al. / Carbohydrate Research 381 (2013) 74–82
1H, H-5), 3.39 (dd, 1H, J = 13.2, 2.2 Hz, H-6a), 3.32 (dd, 1H, J = 13.2,
5.5 Hz, H-6b), 2.19, 2.18, 2.06, 2.01 (s, 12H, 4 ꢂ CH3); LR-ESI-MS m/
z 396.0 [M+Na]+.
the solution was concentrated and the residue was purified by sil-
ica column chromatography (EtOAc–petroleum ether 1:4) to afford
5d (0.58 g, 91% for two steps) as a syrup. 1H NMR (500 MHz,
CDCl3): d 8.91 (s, 1H, NH), 7.26–8.14 (m, 15H, Ar), 6.58 (d, 1H,
J = 1.7 Hz, H-1), 6.02 (t, 1H, J = 9.9 Hz, H-4), 5.91–5.96 (m, 2H,
H-2, H-3), 4.47 (ddd, 1H, J = 8.9, 5.3, 2.4 Hz, H-5), 3.57 (dd, 1H,
J = 13.5, 2.4 Hz, H-6a), 3.51 (dd, 1H, J = 13.5, 5.5 Hz, H-6b),
LR-ESI-MS m/z 683.1 [M+Na]+.
4.1.3. 6-Azido-2,3,4-tri-O-acetyl-6-deoxy-D-mannopyranose (10)
To a solution of compound 9 (0.1 g, 0.27 mmol) in 5 mL DMF,
NH2NH2ꢀHOAc (0.04 g, 0.4 mmol) was added. The reaction mixture
was stirred overnight at 50 °C and the solution was diluted with
CH2Cl2 (30 mL), then washed with saturated NaHCO3 (30 mL ꢂ 2)
and NaCl (30 mL ꢂ 2). The organic layer was dried with Na2SO4
and concentrated. The residue was purified by silica column chro-
matography (EtOAc–petroleum ether 1:3) to afford a white solid
10 (0.08 g, 89%); 1H NMR (500 MHz, CDCl3) b isomer: d 5.39 (dd,
1H, J = 9.9, 3.0 Hz, H-3), 5.21–5.24 (m, 2H, H-2, H-4), 4.17 (ddd,
1H, J = 9.5, 5.3, 3.4 Hz, H-5), 4.10 (d, 1H, J = 3.8 Hz, H-1), 3.32–
3.33 (m, 2H, H-6a, H-6b), 2.15, 2.04, 1.98 (s, 9H, 3 ꢂ –CH3);
LR-ESI-MS m/z 354.1 [M+Na]+.
4.1.7. p-Tolyl 6-azido-2,3,4-tri-O-benzyl-6–deoxy-1-thio-a-D-
mannopyranoside (5e)
To a solution of 5a (2.5 g, 5.7 mmol) in MeOH (60 mL) was
added a catalytic amount NaOMe until reaching pH 9.0. The reac-
tion mixture was stirred for 30 min, and then was neutralized with
Amberlite IR120 resin (H+). After filtration, the filtrate was concen-
trated in vacuo to get a residue. The residue was dissolved in DMF
(20 mL), then BnBr was added (3.0 mL, 25.7 mmol). The reaction
solution was cooled to 0 °C, and then NaH (1.1 g, 60%, 25.7 mmol)
was added portionwise. After stirring for 2 h, methanol (10 mL)
was added to quench the reaction. The mixture was diluted with
water (20 mL) and extracted with CH2Cl2 (30 mL ꢂ 3). All of the
organic extracts were combined, dried over Na2SO4, and concen-
trated. The residue was chromatographed (SiO2, EtOAc–petroleum
ether 1:10) to give the desired product 5e (3.0 g, 92% over two
steps) as a white solid; 1H NMR (600 MHz, CDCl3): d 7.28–7.37
(m, 19H, Ar), 5.48 (d, 1H, J = 1.7 Hz, H-1), 4.56–4.98 (m, 6H,
3 ꢂ PhCH2), 4.24 (ddd, 1H, J = 9.4, 6.1, 3.3 Hz, H-5), 3.99 (dd, 1H,
J = 3.3, 1.6 Hz, H-2), 3.95 (t, 1H, J = 9.4 Hz, H-4), 3.85 (dd, 1H,
J = 9.3, 3.3 Hz, H-3), 3.48 (dd, 1H, J = 12.9, 2.2 Hz, H-6a), 3.43 (dd,
1H, J = 12.9, 6.1 Hz, H-6b), 2.33 (s, 3H, ArCH3); LR-ESI-MS m/z
604.3 [M+Na]+.
4.1.4. p-Tolyl 6-azido-2,3,4-tri-O-acetyl-6-deoxy-1-thio-a-D-
mannopyranoside (5a)
Compound
9 (2.0 g, 5.3 mmol) and p-CH3PhSH (0.87 g,
6.9 mmol) were dissolved in dry 50 mL CH2Cl2, BF3ꢀOEt2 (0.81 mL,
6.4 mmol) was added dropwise at room temperature. The reaction
mixture was stirred for 12 h and then washed with saturated
NaHCO3 (50 mL ꢂ 2) and NaCl (50 mL ꢂ 2). The organic layer was
dried with Na2SO4 and concentrated. The residue was purified by
silica column chromatography (petroleum ether–EtOAc 4:1) to af-
ford a white solid 5a (1.8 g, 78%); ½a D22
ꢃ
+42.6 (c 0.35, CHCl3); 1H
NMR (600 MHz, CDCl3): d 7.40 (d, 2H, J = 7.7 Hz, Ar), 7.14 (d, 2H,
J = 7.7 Hz, Ar), 5.30–5.49 (m, 4H, H-1, H-2, H-3, H-4), 4.47–4.49
(m, 1H, H-5), 3.39 (dd, 1H, J = 13.4, 6.7 Hz, H-6a), 3.31 (dd, 1H,
J = 13.3, 2.4 Hz, H-6b), 2.34 (s, 3H, ArCH3), 2.15, 2.08, 2.02 (s, 9H,
3 ꢂ CH3); LR-ESI-MS m/z 460.0 [M+Na]+, 476.0 [M+K]+.
4.1.8. 6-Azido-2,3,4-tri-O-benzyl-6–deoxy-a-D-mannopyranose-
1-O-trichloroacetimidate (5f)
4.1.5. p-Tolyl 6-azido-2,3,4-tri-O-benzoyl-6–deoxy-1-thio-
mannopyranoside (5c)
a
-
D
-
To a stirred solution of 5e (1.8 g, 3.1 mmol) in acetone (18 mL)
and H2O (2 mL) at ambient temperature was added NBS (1.0 g,
5.7 mmol). After 1 h, the reaction was quenched with saturated
NaHCO3 and the mixture concentrated. The crude intermediate
was diluted with CH2Cl2 (30 mL) and washed sequentially with
saturated NaHCO3 (30 mL), brine (30 mL ꢂ 2), dried over Na2SO4,
and was concentrated. The residue was purified by silica gel col-
umn chromatography to afford a syrup (1.35 g). To a stirred solu-
tion of the syrup (0.15 g, 0.32 mmol) were added CCl3CN (3 mL,
To a solution of 5a (1.0 g, 2.3 mmol) in MeOH (10 mL) was
added NaOMe until reaching pH 9.0. The reaction mixture was stir-
red for 30 min, and then was neutralized with Amberlite IR120 re-
sin (H+). After filtration, the filtrate was concentrated in vacuo to
get a residue. The residue was dissolved in CH2Cl2 (15 mL), then
BzCl (1.2 mL, 10.3 mmol), Et3N (3.3 mL, 23 mmol), and DMAP
(0.03 g, 0.23 mmol) were added at room temperature. After stirring
for 2 h, the mixture was washed with HCl (1 M, 15 mL) and NaCl
(15 mL ꢂ 2). The organic extracts were combined, dried over Na2-
SO4, and concentrated. The residue was chromatographed (SiO2,
EtOAc–petroleum ether 1:5) to give the desired pruduct 5c (1.2 g,
88% over two steps) as a colorless syrup; 1H NMR (500 MHz,
CDCl3): d 7.20–8.15 (m, 19H, Ar), 5.97–6.01 (m, 2H, H-2, H-3),
5.90 (dd, 1H, J = 10.0, 3.1 Hz, H-4), 5.74 (s, 1H, H-1), 4.85 (ddd,
1H, J = 8.9, 6.3, 2.0 Hz, H-5), 3.60 (dd, 1H, J = 13.4, 6.4 Hz, H-6a),
3.53 (dd, 1H, J = 13.4, 2.2 Hz, H-6b), 2.37 (s, 3H, ArCH3); LR-ESI-
MS m/z 646.3 [M+Na]+.
3.2 mmol) and DBU (33 lL, 0.22 mmol) in CH2Cl2 (8 mL) at 0 °C.
After 40 min, the solution was concentrated and the residue was
purified by silica gel column chromatography (EtOAc-petroleum
ether 1:4) to afford 5f (0.18 g, 95%) as
a
syrup. 1H NMR
(500 MHz, CDCl3): d 8.58 (s, 1H, NH), 7.25–7.44 (m, 15H, Ar),
5.48 (s, 1H, H-1), 4.58–4.99 (m, 6H, 3 ꢂ PhCH2), 4.05 (t, 1H,
J = 9.5 Hz, H-4), 3.92–3.97 (m, 2H, H-3, H-5), 3.85 (s, 1H, H-2),
3.55 (dd, 1H, J = 13.2, 1.8 Hz, H-6a), 3.43 (dd, 1H, J = 13.2, 5.3 Hz,
H-6b), LR-ESI-MS m/z 641.1 [M+Na]+.
4.1.9. 3-O-(60-Azido-20,30,40-tri-O-benzoyl-60-deoxy-
a-D-
4.1.6. 6-Azido-2,3,4-tri-O-benzoyl-6–deoxy-
a-
D-mannopy-
mannopyranosyl)-1,2-isopropylidene-sn-glycerol (4-2)
ranose-1-O-trichloroacetimidate (5d)
A mixture of the glycosyl donor 5d (0.2 g, 0.3 mmol) and acti-
vated 4 Å molecular sieves was stirred in dry CH2Cl2 (10 mL) at
0 °C under N2 atmosphere, then acceptor (S)-1,2-isopropylidene-
To a stirred solution of 5c (1.2 g, 1.9 mmol) in acetone (18 mL)
and H2O (2 mL) at ambient temperature NBS (1.0 g, 5.7 mmol)
was added. After 0.5 h, the reaction was quenched with saturated
NaHCO3 and the mixture concentrated. The crude intermediate
was diluted with CH2Cl2 (30 mL) and washed sequentially with
saturated NaHCO3 (30 mL), brine (30 mL ꢂ 2), dried over Na2SO4,
and concentrated. The residue was purified by silica column chro-
matography to afford a paste (0.78 g). To a stirred solution of the
paste (0.5 g, 0.97 mmol) were added CCl3CN (0.5 mL, 4.8 mmol)
glycerol (45
lL, 0.36 mmol) and catalytic amounts of TMSOTf
(5.5 L, 0.03 mmol) were added. The reaction mixture was stirred
l
at 0 °C under a N2 atmosphere for 30 min, when TLC showed that
the reaction was completed. The mixture was quenched by the
addition of Et3N and filtered to remove the sieves. The filtrate
was concentrated by diminished pressure and the residue was dis-
solved in 20 mL CH2Cl2. The solution was washed with saturated
NaHCO3 (15 mL) and brine (15 mL). The organic layer was dried
and DBU (85 lL, 0.58 mmol) in CH2Cl2 (15 mL) at 0 °C. After 2 h,

J. Zhang et al. / Carbohydrate Research 381 (2013) 74–82
79
over Na2SO4, then the solvent was removed in vacuo, and the res-
idue was purified by silica column chromatography (EtOAc–petro-
leum ether 5:1) to afford absolute 4-2 (0.16 g, 83%) as a paste; 1H
NMR(500 MHz, CDCl3): d 7.17–8.05 (m, 15H, Ar), 5.82 (dd, 1H,
J = 9.9, 2.8 Hz, H-3), 5.78 (t, 1H, J = 9.4 Hz, H-4), 5.65 (dd, 1H,
J = 2.8, 1.7 Hz, H-2), 5.08 (dd, 1H, J = 1.6 Hz, H-1), 4.33–4.36 (m,
1H, Hsn-2), 4.23 (ddd, 1H, J = 9.4, 6.4, 2.8 Hz, H-5), 4.09 (dd, 1H,
J = 8.2, 6.1 Hz, Hsn-1a), 3.80–3.84 (m, 2H, Hsn-1b, Hsn-3a), 3.63 (dd,
1H, J = 10.4, 5.4 Hz, Hsn-3b), 3.44 (dd, 1H, J = 13.2, 6.1 Hz, H-6a),
3.41 (dd, 1H, J = 13.2, 2.4 Hz, H-6b), 1.44 (s, 3H, CH3), 1.35 (s, 3H,
CH3); HR-ESI-MS m/z Calcd for C33H39O7N3 Na 654.2 [M+Na]+,
found 654.3.
for 2 h, methanol (10 mL) was added to quench the reaction. The
mixture was diluted with water (10 mL) and extracted with CH2Cl2
(10 mL ꢂ 3). All of the organic extracts were combined, dried over
Na2SO4, and concentrated. The residue was chromatographed
(SiO2, EtOAc–petroleum ether 1:10) to give the desired pruduct
4-3 (0.07 g, 89% over two steps) as a syrup.
4.1.11. 3-O-(60-Amino-20,30,40-tri-O-benzyl-60-deoxy-
mannopyranosyl)-sn-glycerol (3)
a-D-
TsOH (0.58 g, 3 mmol) was added to a stirred solution of 4-3
(0.9 g, 1.50 mmol) in MeOH (50 mL). After stirring for 2 h at ambi-
ent temperature, the solution was concentrated and dissolved in
CH2Cl2 and was washed sequentially with satd aq NaHCO3 and
water, dried over Na2SO4, filtered, and concentrated to give crude
11. The crude 11 was dissolved in THF (40 mL) and water
(0.3 mL), and then PPh3 (0.76 g, 2.92 mmol) was added. The reac-
tion mixture was heated at 50 °C for 5 h and then cooled to room
temperature. The mixture was evaporated under diminished pres-
sure, and the residue was purified by silica column chromatogra-
phy (CH2Cl2/MeOH) to obtain 3 (0.76 g, 95% over two steps) as a
colorless waxy substance; 1H NMR (500 MHz, CDCl3): d 7.24–7.35
(m, 15H, Ar), 4.53–4.89 (m, 6H, 3 ꢂ PhCH2), 4.60 (s, 1H, H-1),
3.84 (dd, 1H, J = 8.9, 2.8 Hz, H-3), 3.77–3.82 (m, 2H, Hsn-2, H-5),
3.74 (dd, 1H, J = 9.9, 6.4 Hz, Hsn-1a), 3.67 (t, 1H, J = 9.3 Hz, H-4),
3.62 (d, 1H, J = 3.4 Hz, H-2), 3.46 (dd, 1H, J = 9.9, 5.9 Hz, Hsn-1b),
3.85–3.90 (m, 2H, Hsn-3a, Hsn-3b), 3.33–3.35 (m, 1H, NH2), 3.14 (d,
1H, J = 12.0 Hz, H-6a), 2.80 (dd, 1H, J = 12.0, 10.2 Hz, H-6b0); LR-
ESI-MS m/z 524.0 [M+H]+.
4.1.10. 3-O-(60-Azido-20,30,40-tri-O-benzyl-60-deoxy-
mannopyranosyl)-1,2-isopropylidene-sn-glycerol (4-3)
a-D-
4.1.10.1. For donor 5e.
A mixture of the glycosyl donor 5e
(2.5 g, 4.3 mmol) and activated 4 Å molecular sieves was stirred
in dry CH2Cl2 (100 mL) at room temperature under N2 atmosphere.
The reaction mixture was cooled in an ice bath and NIS (1.4 g,
6.4 mmol) was added. After stirring for 10 min, DTBMP (0.18 g,
0.86 mmol) was added, followed by the addition of acceptor (S)-
1,2-isopropylideneglycerol (0.58 mL, 4.7 mmol) and TMSOTf
(77.6 ll, 0.43 mmol). The reaction mixture was stirred at 0 °C un-
der N2 atmosphere for 16 h, when TLC showed that the reaction
was complete. The mixture was quenched by the addition of
Et3N and filtered through a pad of Celite. The mixture was washed
with 10% Na2S2O3 (100 mL), followed by satd aq NaHCO3
(100 mL ꢂ 2). The organic layer was dried over Na2SO4, and the sol-
vent was removed in vacuo. The residue was purified by silica col-
umn chromatography (EtOAc–petroleum ether 1:10) to afford 4-3
4.1.12. General procedure for 12a–h formation
(1.13 g, 43% yield for the product of alpha configuration,
a
/b = 1:1)
To a solution of compound 3 (0.08 g, 0.15 mmol) in dry pyridine
(4 mL), a catalytic amount of DMAP (0.004 g, 0.03 mmol) and acyl
chloride (6 equiv) were added. The reaction mixture was stirred at
room temperature for 4 h, and then was diluted with EtOAc
(15 mL) and washed sequentially with satd aq NH4Cl (15 mL).
The organic phase was dried over Na2SO4, filtrated, and concen-
trated. Purification by flash chromatography (petroleum ether–
EtOAc) yielded the corresponding compound 19a–h (70–90%) as
a colorless syrup or white solid.
as a colorless syrup;
a
isomer: ½a 2D2
ꢃ
+34.3 (c 2.9, CHCl3); 1H NMR
(600 MHz, CDCl3): d 7.25–7.38 (m, 15H, Ar), 4.57–4.95 (m, 6H,
3 ꢂ PhCH2), 4.87 (d, 1H, J = 1.6 Hz, H-1), 4.21–4.23 (m, 1H, Hsn-2),
4.02(dd, 1H, J = 8.5, 6.1 Hz, Hsn-1a), 3.85–3.90 (m, 3H, H-2, H-3, H-
4), 3.73–3.76 (m, 1H, H-5), 3.68 (dd, 1H, J = 10.4, 4.4 Hz, Hsn-3a),
3.63 (dd, 1H, J = 8.5, 6.6 Hz, Hsn-1b), 3.45–3.49 (m, 2H, H-6a, Hsn-
3b), 3.41 (dd, 1H, J = 13.2, 6.6 Hz, H-6b), 1.39 (s, 3H, CH3), 1.36 (s,
3H, CH3); HR-ESI-MS m/z Calcd for C33H39O7N3 Na 612.2680
[M+Na]+, found: 612.2669.
4.1.12.1. 1,2-Dihexanoyl-3-O-(N-hexanoyl-60-amino-20,30,40-tri-
4.1.10.2. For donor 5f.
A mixture of the glycosyl donor 5f
O-benzyl-60-deoxy-
a
-
D
-mannopyranosyl)-sn-glycerol
(12a,
(0.04 g, 0.06 mmol) and activated 4 Å molecular sieves was stirred
in dry Et2O (3 mL) at 0 °C under N2 atmosphere, then acceptor (S)-
75%).
½ ꢃ
a 2D2
+9.2 (c 1.3, CHCl3); 1H NMR (600 MHz, CDCl3): d
7.27–7.37 (m, 15H, Ar), 5.87 (dd, 1H, J = 7.2, 3.3 Hz, NH–CO),
5.11–5.14 (m, 1H, Hsn-2), 4.61–4.86 (m, 6H, 3 ꢂ PhCH2), 4.77 (d,
1H, J = 2.2 Hz, H-1), 4.32 (dd, 1H, J = 12.7, 6.6 Hz, Hsn-1a), 4.05 (dd,
1H, J = 12.1, 6.1 Hz, Hsn-1b), 3.83–3.87 (m, 2H, H-2, H-6a), 3.76 (t,
1H, J = 9.4 Hz, H-4), 3.70–3.73 (m, 2H, H-3, Hsn-3a), 3.62 (dt, 1H,
J = 8.0, 3.7 Hz, H-5), 3.51 (dd, 1H, J = 11.0, 5.5 Hz, Hsn-3b), 3.36 (dt,
J = 13.9, 3.8 Hz, 1H, H-6b), 2.27–2.32 (m, 4H, 2 ꢂ CO–CH2), 2.11
(t, 2H, J = 6.1 Hz, NHCO–CH2), 1.57–1.64 (m, 6H, 3 ꢂ CO–CH2–
CH2), 1.26–1.34(m, 12H, 3 ꢂ CH2–CH2(CH2)2–CH3), 0.87–0.89 (m,
9H, 3 ꢂ CH3); HR-ESI-MS m/z Calcd for C48H67O10N Na 840.4657
[M+Na]+, found 840.4657.
1,2-isopropylideneglycerol (10
lL, 0.07 mmol) and catalytic
amounts of TMSOTf (2 L, 0.01 mmol) were added. The reaction
l
mixture was stirred at 0 °C under an N2 atmosphere for 2 h, when
TLC showed that the reaction was completed. The mixture was
quenched by the addition of Et3N and filtered to remove the sieves.
The filtrate was concentrated by diminished pressure and the res-
idue was dissolved in 10 mL CH2Cl2. The solution was washed with
saturated NaHCO3 (10 mL) and brine (10 mL). The organic layer
was dried over Na2SO4, then the solvent was removed in vacuo,
and the residue was purified by silica column chromatography
(EtOAc–petroleum ether 1:8) to afford a mixture of 4-3 and 40-3
(0.04 g, 87%,
a/b = 1:1) as a paste.
4.1.12.2. 1,2-Dioctanoyl-3-O-(N-octanoyl-60-amino-20,30,40-tri-O-
benzyl-60-deoxy-
89%).
a
-
D
-mannopyranosyl)-sn-glycerol
(12b,
4.1.10.3. For 4-2.
To a solution of 4-2 (0.1 g, 0.15 mmol) in
½ ꢃ
a 2D2
+5.1 (c 0.25, CHCl3); 1H NMR (600 MHz, CDCl3): d
MeOH (5 mL) was added a catalytic amount of NaOMe until reach-
ing pH 9.0. The reaction mixture was stirred for 30 min, and then
was neutralized with Amberlite IR120 resin (H+). After filtration,
the filtrate was concentrated in vacuo to get a residue. The residue
was dissolved in DMF (5 mL), then BnBr was added (85 lL,
0.7 mmol). The reaction solution was cooled to 0 °C, and then
7.26–7.37 (m, 15H, Ar), 5.83 (dd, 1H, J = 7.2, 3.3 Hz, NH-CO),
5.13–5.15 (m, 1H, Hsn-2), 4.61–4.86 (m, 6H, 3 ꢂ PhCH2), 4.76 (d,
1H, J = 2.2 Hz, H-1), 4.30 (dd, 1H, J = 12.1, 4.4 Hz, Hsn-1a), 4.05 (dd,
1H, J = 12.1, 6.6 Hz, Hsn-1b), 3.85–3.87 (m, 2H, H-2, H-6a), 3.76 (t,
1H, J = 9.9 Hz, H-4), 3.69–3.72 (m, 2H, H-3, Hsn-3a), 3.61 (dt,
J = 8.3, 3.9 Hz, 1H, H-5), 3.51 (dd, 1H, J = 11.0, 5.5 Hz, Hsn-3b), 3.35
(dt, J = 13.7, 3.6 Hz, 1H, H-6b), 2.26–2.30 (m, 4H, 2 ꢂ CO–CH2–),
NaH (0.03 g, 60%, 0.7 mmol) was added in batches. After stirring

80
J. Zhang et al. / Carbohydrate Research 381 (2013) 74–82
2.10 (t, 2H, J = 6.5 Hz, NHCO–CH2), 1.57–1.62 (m, 6H, 3 ꢂ CO–CH2–
CH2), 1.25–1.32 (m, 24H, 3 ꢂ CH2–CH2(CH2)4–CH3), 0.86–0.88 (m,
9H, 3 ꢂ CH3); LR-ESI-MS m/z 902.8 [M+H]+.
7.26–7.37 (m, 15H, Ar), 5.83 (dd, 1H, J = 7.2, 3.3 Hz, NH–CO),
5.14–5.16 (m, 1H, Hsn-2), 4.62–4.87 (m, 6H, 3 ꢂ PhCH2), 4.76 (d,
1H, J = 2.2 Hz, H-1), 4.30 (dd, 1H, J = 12.1, 3.3 Hz, Hsn-1a), 4.05 (dd,
1H, J = 12.1, 6.6 Hz, Hsn-1b), 3.86–3.89 (m, 2H, H-2, H-6a), 3.76 (t,
1H, J = 9.9 Hz, H-4), 3.70–3.73 (m, 2H, H-3, Hsn-3a), 3.60–3.63 (m,
1H, H-5), 3.51 (dd, 1H, J = 11.0, 5.5 Hz, Hsn-3b), 3.35- 3.38 (m, 1H,
H-6b), 1.95–2.19 (m, 9H, 3 ꢂ CO–CH2CH(CH3)2), 0.90–0.95 (m,
4.1.12.3.
benzyl-60-deoxy-
90%).
+6.5 (c 1.0, CHCl3); 1H NMR (600 MHz, CDCl3): d
1,2-Dilauroyl-3-O-(N-lauroyl-60-amino-20,30,40-tri-O-
-mannopyranosyl)-sn-glycerol (12c,
a-D
½ ꢃ
a 2D2
7.26–7.37 (m, 15H, Ar), 5.84 (dd, 1H, J = 7.2, 3.3 Hz, NH–CO),
5.12–5.14 (m, 1H, Hsn-2), 4.61–4.86 (m, 6H, 3 ꢂ PhCH2), 4.76 (d,
1H, J = 2.2 Hz, H-1), 4.30 (dd, 1H, J = 12.1, 3.3 Hz, Hsn-1a), 4.05 (dd,
1H, J = 12.1, 6.6 Hz, Hsn-1b), 3.85–3.87 (m, 2H, H-2, H-6a), 3.76 (t,
1H, J = 9.9 Hz, H-4), 3.69–3.72 (m, 2H, H-3, Hsn-3a), 3.61–3.63 (m,
1H, H-5), 3.51 (dd, 1H, J = 11.0, 5.5 Hz, Hsn-3b), 3.35 (dt, 1H,
J = 13.9, 3.6 Hz, H-6b), 2.26–2.30 (m, 4H, 2 ꢂ CO–CH2), 2.10 (t,
2H, J = 8.8 Hz, NHCO–CH2), 1.57–1.62 (m, 6H, 3 ꢂ CO–CH2–CH2),
1.25–1.32 (m, 48H, 3 ꢂ CH2–CH2(CH2)8–CH3), 0.87 (t, 9H,
J = 6.6 Hz, 3 ꢂ CH3); HR-MALDI/DHB-MS m/z Calcd for
18H, 3 ꢂ CO-CH2CH(CH3)2); HR-ESI-MS m/z Calcd for C45H61O10
N
Na 798.4188 [M+Na]+, found 798.4197.
4.1.12.8.
amino-20,30,40-tri-O-benzyl-60-deoxy-
glycerol (12h, 75%).
+5.0 (c 1.0, CHCl3); 1H NMR
1,2-Dihydrocinnamoyl-3-O-(N-hydrocinnamoyl-60-
-mannopyranosyl)-sn-
a-D
½ ꢃ
a 2D2
(600 MHz, CDCl3): d 7.16–7.68 (m, 30H, Ar), 5.88 (dd, 1H, J = 7.2,
3.3 Hz, –NH–CO–), 5.08–5.10 (m, 1H, Hsn-2), 4.53–4.81 (m, 6H,
3 ꢂ PhCH2), 4.72 (d, 1H, J = 2.2 Hz, H-1), 4.25 (dd, 1H, J = 8.8,
3.3 Hz, Hsn-1a), 4.03 (dd, 1H, J = 12.1, 5.5 Hz, Hsn-1b), 3.80–3.85
(m, 2H, H-2, H-6a), 3.71 (t, 1H, J = 9.9 Hz, H-4), 3.59–3.66 (m,
2H, H-3, Hsn-3a), 3.56–3.58 (m, 1H, H-5), 3.41 (dd, 1H, J = 11.0,
5.5 Hz, Hsn-3b), 3.34 (dt, 1H, J = 13.3, 3.1 Hz, H-6b), 2.40–2.90
C
66H103O10N Na 1092.7474 [M+Na]+, found 1092.7464.
4.1.12.4. 1,2-Dimyristoyl-3-O-(N-myristoyl-60-amino-20,30,40-tri-
O-benzyl-60-deoxy-
-mannopyranosyl)-sn-glycerol (12d,
83%).
+7.7 (c 0.85, CHCl3); 1H NMR (600 MHz, CDCl3): d
a-
D
(m, 12H, 3 ꢂ COCH2CH2); HR-ESI-MS m/z Calcd for C57H62O10
N
½
a 2D2
ꢃ
920.4368 [M+H] +, found 920.4373.
7.26–7.37 (m, 15H, Ar), 5.84 (dd, 1H, J = 7.2, 3.3 Hz, NH–CO),
5.12–5.14 (m, 1H, Hsn-2), 4.61–4.86 (m, 6H, 3 ꢂ PhCH2), 4.76 (d,
1H, J = 2.2 Hz, H-1), 4.30 (dd, 1H, J = 12.1, 4.4 Hz, Hsn-1a), 4.05 (dd,
1H, J = 12.1, 6.5 Hz, Hsn-1b), 3.85–3.87 (m, 2H, H-2, H-6a), 3.76 (t,
1H, J = 9.9 Hz, H-4), 3.69–3.72 (m, 2H, H-3, Hsn-3a), 3.60–3.63 (m,
1H, H-5), 3.51 (dd, 1H, J = 11.0, 5.5 Hz, Hsn-3b), 3.35 (dt, 1H,
J = 13.7, 3.6 Hz, H-6b), 2.26–2.29 (m, 4H, 2 ꢂ CO–CH2), 2.10 (t,
2H, J = 6.6 Hz, NHCO–CH2), 1.57–1.62 (m, 6H, 3 ꢂ CO–CH2–CH2),
1.22–1.32 (m, 60H, 3 ꢂ CH2–CH2(CH2)10–CH3), 0.88 (t, 9H,
J = 6.6 Hz, 3 ꢂ CH3); HR-MALDI/DHB-MS m/z Calcd for
4.1.13. General procedure for 2a–h formation
A solution of 2a–h (0.1 g) in 20 mL THF/i-PrOH (9:1) was trea-
ted with 10% palladium hydroxide (0.1 g) and stirred at ambient
temperature under hydrogen atmosphere for 8 h. After filtration
the solvent was evaporated and the residue was purified by silica
column chromatography (CH2Cl2–MeOH) to afford 2a–h (80–
94%) as a colorless syrup or waxy solid.
4.1.13.1. 1,2-Dihexanoyl-3-(N-hexanoyl-60-amino-60-deoxy-
mannopyranosyl)-sn-glycerol (2a, 83%).
a-D-
ꢁ52.1 (c 1.9,
C
72H115O10N Na 1176.8413 [M+Na]+, found 1176.8434.
½
a 2D2
ꢃ
CHCl3); 1H NMR (600 MHz, CDCl3): d 6.50 (dd, 1H, J = 12.1,
4.4 Hz, –NHCO–), 5.18–5.20 (m, 1H, Hsn-2), 4.79 (d, 1H, J = 2.2 Hz,
H-1), 4.33 (dd, 1H, J = 12.1, 4.4 Hz, Hsn-1a), 4.12 (dd, 1H, J = 13.2,
5.5 Hz, Hsn-1b), 3.92–3.96 (m, 2H, H-2, H-6a), 3.82 (dd, 1H, J = 8.8,
3.3 Hz, H-3), 3.75 (dd, 1H, J = 11.0, 5.5 Hz, Hsn-3a), 3.58 (dd, 1H,
J = 9.9, 5.5 Hz, Hsn-3b), 3.49–3.55 (m, 2H, H-4, H-5), 3.13–3.16 (m,
1H, H-6b), 2.29–2.32 (m, 4H, 2 ꢂ CO–CH2), 2.24–2.26 (m, 2H,
NHCO–CH2), 1.60–1.65 (m, 6H, 3 ꢂ CO–CH2–CH2), 1.26–1.33 (m,
12H, 3 ꢂ CH2–CH2(CH2)2–CH3), 0.88–0.90 (m, 9H, 3 ꢂ CH3); 13C
NMR (150 MHz, CDCl3): d 14.1, 22.4, 22.5, 24.7, 24.8, 25.6, 31.4–
31.6, 34.2, 34.3, 36.5, 40.1, 62.6, 66.1, 67.4, 69.9, 70.3, 70.6, 71.7,
4.1.12.5. 1,2-Dipalmitoyl-3-O-(N-palmitoyl-60-amino-20,30,40-tri-
O-benzyl-60-deoxy-
-mannopyranosyl)-sn-glycerol (12e,
84%).
+7.0 (c 0.7, CHCl3); 1H NMR (600 MHz, CDCl3): d
a-D
½ ꢃ
a 2D2
7.26–7.37 (m, 15H, Ar), 5.84 (dd, 1H, J = 7.2, 3.3 Hz, NH–CO),
5.12–5.14 (m, 1H, Hsn-2), 4.61–4.86 (m, 6H, 3 ꢂ PhCH2), 4.76 (d,
1H, J = 2.2 Hz, H-1), 4.29 (dd, 1H, J = 12.1, 3.3 Hz, Hsn-1a), 4.05 (dd,
1H, J = 12.1, 4.9 Hz, Hsn-1b), 3.85–3.87 (m, 2H, H-2, H-6a), 3.76 (t,
1H, J = 9.9 Hz, H-4), 3.69–3.72 (m, 2H, H-3, Hsn-3a), 3.60–3.63 (m,
1H, H-5), 3.51 (dd, 1H, J = 11.0, 5.5 Hz, Hsn-3b), 3.35 (dt, 1H,
J = 13.8, 3.6 Hz, H-6b), 2.26–2.29 (m, 4H, 2 ꢂ CO–CH2), 2.10 (t,
2H, J = 6.6 Hz, NHCO–CH2), 1.55–1.62 (m, 6H, 3 ꢂ CO–CH2–CH2),
1.21–1.32 (m, 72H, 3 ꢂ CH2–CH2(CH2)12–CH3), 0.88 (t, 9H,
J = 6.6 Hz, 3 ꢂ CH3); HR-MALDI/DHB-MS m/z Calcd for
100.6, 173.3, 173.6, 176.1; HR-ESI-MS m/z Calcd for C27H50O10
N
548.3429 [M+H]+, found 548.3435.
C
78H127O10N Na 1260.9352 [M+Na]+, found 1260.9343.
4.1.13.2. 1,2-Dioctanoyl-3-(N-octanoyl-60-amino-60-deoxy-
a-D-
mannopyranosyl)-sn-glycerol (2b, 89%).
½
a 2D2
ꢃ
ꢁ4.1 (c 1.1,
4.1.12.6. 1,2-Distearoyl-3-O-(N-stearoyl-60-amino-20,30,40-tri-O-
benzyl-60-deoxy-
-mannopyranosyl)-sn-glycerol (12f,
70%).
+6.8 (c 1.0, CHCl3); 1H NMR (600 MHz, CDCl3): d
CHCl3); 1H NMR (600 MHz, CDCl3): d 6.22 (dd, 1H, J = 7.7, 4.4 Hz,
–NH–CO–), 5.11–5.14 (m, 1H, Hsn-2), 4.72 (d, 1H, J = 2.2 Hz, H-1),
4.26 (dd, 1H, J = 12.1, 3.3 Hz, Hsn-1a), 4.05 (dd, 1H, J = 12.1, 6.6 Hz,
a-D
½ ꢃ
a 2D2
7.26–7.37 (m, 15H, Ar), 5.84 (dd, 1H, J = 7.2, 3.3 Hz, NH–CO),
5.15–5.12 (m, 1H, Hsn-2), 4.61–4.86 (m, 6H, 3 ꢂ PhCH2), 4.76 (d,
1H, J = 2.2 Hz, H-1), 4.29 (dd, 1H, J = 12.1, 3.3 Hz, Hsn-1a), 4.05 (dd,
1H, J = 12.1, 6.5 Hz, Hsn-1b), 3.85–3.87 (m, 2H, H-2, H-6a), 3.76 (t,
1H, J = 9.9 Hz, H-4), 3.69–3.72 (m, 2H, H-3, Hsn-3a), 3.60–3.63 (m,
1H, H-5), 3.51 (dd, 1H0, J = 11.0, 5.5 Hz, Hsn-3b), 3.35 (dt, 1H,
J = 13.7, 3.7 Hz, H-6b), 2.26–2.29 (m, 4H, 2 ꢂ CO–CH2), 2.10 (t,
2H, J = 6.6 Hz, NHCO–CH2), 1.55–1.62 (m, 6H, 3 ꢂ CO–CH2–CH2),
1.21–1.35 (m, 84H, 3 ꢂ CH2–CH2(CH2)14–CH3), 0.88 (t, 9H,
J = 6.6 Hz, CH3); LR-ESI-MS m/z [M+Na]+ 1345.0.
H
sn-1b), 3.96–4.01 (m, 1H, H-6a), 3.89 (dd, 1H, J = 3.3, 1.4 Hz, H-
2), 3.78 (dd, 1H, J = 8.8, 3.3 Hz, H-3), 3.69 (dd, 1H, J = 11.0, 5.5 Hz,
sn-3a), 3.52 (dd, 1H, J = 11.0, 5.5 Hz, Hsn-3b), 3.47 (dt, J = 9.7,
H
2.4 Hz, 1H, H-5), 3.41(t, 1H, J = 8.8 Hz, H-4), 3.01 (ddd, J = 14.8,
4.4, 2.7 Hz, 1H, H-6b), 2.22–2.25 (m, 4H, 2 ꢂ CO–CH2), 2.18–2.21
(m, 2H, NHCO–CH2), 1.52–1.57 (m, 6H, 3 ꢂ CO–CH2–CH2), 1.20–
1.29 (m, 24H, 3 ꢂ CH2–CH2(CH2)4–CH3), 0.83–0.85 (m, 9H,
3 ꢂ CH3); 13C NMR (150 MHz, CDCl3): d 14.3, 22.8, 25.1, 25.2,
25.9, 29.1–29.3, 31.9, 34.3, 34.5, 36.7, 40.1, 62.6, 66.2, 67.2, 70.0,
70.3, 70.6, 71.8, 100.6, 173.3, 173.6, 176.3; HR-ESI-MS m/z Calcd
for C33H62O10N 632.4368 [M+H]+, found 632.4386.
4.1.12.7. 1,2-Diisovaleryl-3-O-(N-isovaleryl-60-amino-20,30,40-tri-
O-benzyl-60-deoxy-
a
-
D
-mannopyranosyl)-sn-glycerol
(12g,
4.1.13.3.
mannopyranosyl)-sn-glycerol (2c, 94%).
1,2-Dilauroyl-3-(N-lauroyl-60-amino-60-deoxy-
ꢁ2.3 (c 2.9,
a-D-
82%).
½
a 2D2
ꢃ
+5.0 (c 0.6, CHCl3); 1H NMR (600 MHz, CDCl3): d
½ ꢃ
a 2D2

J. Zhang et al. / Carbohydrate Research 381 (2013) 74–82
81
CHCl3); 1H NMR (600 MHz, CDCl3): d 6.53 (dd, 1H, J = 12.1, 4.4 Hz,
4.1.13.7. 1,2-Diisovaleryl-3-(N-isovaleryl-60-amino-60-deoxy-
-mannopyranosyl)-sn-glycerol (2g, 80%).
a-
NH–CO), 5.18–5.20 (m, 1H, Hsn-2), 4.79 (d, 1H, J = 2.2 Hz, H-1), 4.34
(dd, 1H, J = 12.1, 3.3 Hz, Hsn-1a), 4.12 (dd, 1H, J = 12.1, 6.6 Hz, Hsn-
1b), 3.92–3.96 (m, 2H, H-2, H-6a), 3.82 (dd, 1H, J = 8.8, 3.3 Hz, H-
3), 3.74 (dd, 1H, J = 11.0, 4.4 Hz, Hsn-3a), 3.57 (dd, 1H, J = 11.0,
5.5 Hz, Hsn-3b), 3.49–3.55 (m, 2H, H-4, H-5), 3.12–3.14 (m, 1H, H-
6b), 2.29–2.31 (m, 4H, 2 ꢂ CO–CH2), 2.24–2.26 (m, 2H, NHCO–
CH2), 1.58–1.62 (m, 6H, 3 ꢂ CO–CH2–CH2), 1.22–1.31 (m, 48H,
3 ꢂ CH2–CH2(CH2)8–CH3), 0.88 (t, 9H, J = 7.7 Hz, 3 ꢂ CH3); 13C
NMR (150 MHz, CDCl3): d 14.3, 22.9, 25.0- 25.1, 25.9, 29.5–29.8,
32.1, 34.2, 34.3, 34.5, 36.6, 40.1, 62.6, 66.1, 67.4, 69.9, 70.3, 70.6,
71.7, 100.6, 173.3, 173.6, 176.2; HR-ESI-MS m/z Calcd for
D
½
a 2D2
ꢃ
ꢁ63.5 (c
1.2, CHCl3); 1H NMR (600 MHz, CDCl3): d 6.64 (dd, 1H, J = 7.7,
4.9 Hz, NH-CO), 5.12–5.14 (m, 1H, Hsn-2, 4.71 (d, 1H, J = 2.2 Hz, H-
1), 4.26 (dd, 1H, J = 12.1, 3.9 Hz, Hsn-1a), 4.04 (dd, 1H, J = 12.1,
6.6 Hz, Hsn-1b), 3.85–3.89 (m, 2H, H-2, H-6a), 3.74 (dd, 1H, J = 9.4,
3.3 Hz, H-3), 3.68 (dd, 1H, J = 10.4, 4.9 Hz, Hsn-3a), 3.50 (dd, 1H,
J = 11.0, 5.5 Hz, Hsn-3b), 3.44–3.50 (m, 2H, H-4, H-5), 3.05–3.09
(m, 1H, H-6b), 1.97–2.13 (m, 9H, 3 ꢂ CO-CH2CH(CH3)2), 0.88 (m,
18H, 6 ꢂ CH3); 13C NMR (150 MHz, CDCl3): d 22.4–22.6, 25.7,
25.8, 26.2, 40.0, 43.2, 43.4, 45.7, 62.4, 66.0, 67.5, 69.8, 70.3, 70.6,
71.7, 100.6, 172.4, 172.7, 175.1; HR-ESI-MS m/z Calcd for
C
45H86O10N 800.6246 [M+H]+, found 800.6269.
C
24H44O10N 506.2960 [M + H] +, found 506.2970.
4.1.13.8.
amino-60-deoxy-
82%).
d 7.26–7.27 (m, 15H, Ar), 6.22 (dd, 1H, J = 7.7, 4.4 Hz, NH–CO),
5.13–5.15 (m, 1H, Hsn-2), 4.69 (d, 1H, J = 2.2 Hz, H-1), 4.26 (dd,
1H, J = 12.1, 4.4 Hz, Hsn-1a), 4.06 (dd, 1H, J = 11.0, 5.5 Hz, Hsn-1b),
3.95 (ddd, J = 14.7, 8.4, 2.5 Hz, 1H, H-6a), 3.86–3.88 (m, 1H, H-2),
3.79 (dd, 1H, J = 9.9, 3.3 Hz, H-3), 3.63 (dd, 1H, J = 11.0, 5.5 Hz,
1,2-Dihydrocinnamoyl-3-(N-hydrocinnamoyl-60-
4.1.13.4. 1,2-Dimyristoyl-3-(N-myristoyl-60-amino-60-deoxy-
-mannopyranosyl)-sn-glycerol (2d, 92%).
ꢁ2.9 (c 2.5,
a-
D
½ ꢃ
a 2D2
a
-
D
-mannopyranosyl)-sn-glycerol
(2h,
CHCl3); 1H NMR (600 MHz, CDCl3): d 6.39 (dd, 1H, J = 12.1,
4.4 Hz, NH-CO), 5.18–5.20 (m, 1H, Hsn-2), 4.79 (d, 1H, J = 2.2 Hz,
H-1), 4.33 (dd, 1H, J = 12.1, 3.3 Hz, Hsn-1a), 4.12 (dd, 1H, J = 12.1,
5.5 Hz, Hsn-1b), 3.92–3.96 (m, 2H, H-2, H-6a), 3.83 (dd, 1H, J = 8.8,
3.3 Hz, H-3), 3.74 (dd, 1H, J = 11.0, 4.4 Hz, Hsn-3a), 3.58 (dd, 1H,
J = 11.0, 6.6 Hz, Hsn-3b), 3.51–3.53 (m, 1H, H-5), 3.46 (t, J = 9.5 Hz,
1H, H-4), 3.09–3.13 (m, 1H, H-6b), 2.28–2.31 (m, 4H, 2 ꢂ CO–
CH2), 2.24–2.26 (m, 2H, NHCO-CH2), 1.58–1.62 (m, 6H, 3 ꢂ CO–
CH2–CH2), 1.23–1.31 (m, 60H, 3 ꢂ CH2–CH2(CH2)10–CH3), 0.88 (t,
9H, J = 6.6 Hz, 3 ꢂ CH3); 13C NMR (150 MHz, CDCl3): d 14.3, 22.9,
25.1, 25.2, 26.0, 29.5–29.9, 32.1, 34.3, 34.5, 36.6, 40.1, 62.6, 66.2,
67.3, 70.0, 70.3, 70.6, 71.8, 100.6, 173.3, 173.6, 176.2; HR-ESI-MS
m/z Calcd for C51H98O10N 884.7185 [M+H]+, found 884.7212.
½
a 2D2
ꢃ
ꢁ4.4 (c 0.70, CHCl3); 1H NMR (600 MHz, CDCl3):
Hsn-3a), 3.43-.3.47 (m, 2H, Hsn-3b, H-5), 3.28 (t, 1H, J = 9.9 Hz, H-
4), 2.95–2.99 (m, 1H, H-6b), 2.87–2.93 (m, 6H, 3 ꢂ COCH2CH2Ph),
2.54–2.62 (m, 6H, 3 ꢂ COCH2CH2Ph); 13C NMR (150 MHz, CDCl3):
d 30.9, 31.6, 35.7, 35.8, 38.1, 40.1, 62.7, 66.0, 67.0, 70.2–70.5,
71.6, 100.5, 126.5–128.8, 140.3–140.7, 172.4, 172.7, 175.0; HR-
ESI-MS m/z Calcd for
650.2969.
C36H44O10N
650.2960 [M+H]+, found,
4.2. Evaluation of the antiviral activity
4.1.13.5. 1,2-Dipalmitoyl-3-(N-palmitoyl-60-amino-60-deoxy-
-mannopyranosyl)-sn-glycerol (2e, 92%).
ꢁ2.5 (c 2.8,
a-
D
½ ꢃ
a 2D2
The antiviral activity was evaluated by the cytopathic effects
(CPE) inhibition assay as described previously.45,46 MDCK cell cul-
tures in 96-well plates were firstly infected with IAV (MOI = 0.1),
and then treated with different compounds (dissolved in DMSO)
in triplicate after removal of the virus inoculum. After 24 h incuba-
tion, the cells were fixed with 4% formaldehyde for 10 min at room
temperature. After removal of the formaldehyde, the cells were
stained with 0.1% crystal violet for 20 min. The plates were washed
and dried, and the intensity of crystal violet staining for each well
was measured at 570 nm. The virus inhibition (%) was calculated
by the equation:
CHCl3); 1H NMR (600 MHz, CDCl3): d 6.56 (dd, 1H, J = 12.1,
4.4 Hz, NH–CO), 5.18–5.20 (m, 1H, Hsn-2), 4.79 (d, 1H, J = 2.2 Hz,
H-1), 4.33 (dd, 1H, J = 12.1, 3.3 Hz, Hsn-1a), 4.12 (dd, 1H, J = 11.0,
5.5 Hz, Hsn-1b), 4.05 (ddd, 1H, J = 14.6, 8.5, 2.1 Hz, H-6a), 3.96 (dd,
1H, J = 3.3, 1.1 Hz, H-2), 3.83 (dd, 1H, J = 8.8, 3.3 Hz, H-3), 3.74
(dd, 1H, J = 11.0, 4.4 Hz, Hsn-3a), 3.58 (dd, 1H, J = 11.0, 5.5 Hz, Hsn-
3b), 3.64 (dt, 1H, J = 9.7, 2.4 Hz, H-5), 3.45 (t, 1H, J = 9.6 Hz, H-4),
3.09–3.13 (m, 1H, H-6b), 2.28–2.32 (m, 4H, 2 ꢂ –CO–CH2–), 2.24–
2.26 (m, 2H, –NHCO–CH2–), 1.58–1.62 (m, 6H, 3 ꢂ CO–CH2–CH2),
1.23–1.31 (m, 72H, 3 ꢂ CH2–CH2(CH2)12–CH3), 0.88 (t, 9H,
J = 6.6 Hz, 3 ꢂ CH3); 13C NMR (150 MHz, CDCl3): d 14.3, 22.9, 25.1,
25.2, 25.9, 29.3–29.7, 32.1, 34.3–34.5, 36.6, 40.0, 62.6, 64.5, 67.4,
69.9, 70.3, 70.6, 71.7, 100.5, 173.3, 173.6, 176.2; HR-MALDI-MS
m/z Calcd for C57H109O10N Na 990.7949 [M+Na]+, found 990.7919.
Virus inhibition ð%Þ ¼ ½ðAsample570 ꢁ Avirus570Þ=ðAmock570 ꢁ Avirus570Þꢃ
ꢂ 100
where, Amock 570 was the absorbance without virus infection, Asample
4.1.13.6.
1,2-Distearoyl-3-(N-stearoyl-60-amino-60-deoxy-
a-D-
was absorbance with virus infection and drug, Avirus
was
570
570
mannopyranosyl)-sn-glycerol (2f, 85%).
½
a 2D2
ꢃ
ꢁ13.1 (c 0.25,
absorbance with virus infection but without drugs.
CHCl3); 1H NMR (600 MHz, CDCl3): d 6.49 (dd, 1H, J = 8.8, 4.4 Hz,
NH–CO), 5.18–5.20 (m, 1H, Hsn-2), 4.78 (d, 1H, J = 2.2 Hz, H-1),
4.33 (dd, 1H, J = 12.1, 5.5 Hz, Hsn-1a), 4.12 (dd, 1H, J = 11.0, 4.4 Hz,
Acknowledgements
H
sn-1b), 4.03 (ddd, 1H, J = 14.8, 8.6, 2.4 Hz, H-6a), 3.94–3.96 (m,
This work was supported by National Natural Science Founda-
tion of China (No. 81072574), program for New Century Excellent
Talents in the University (NCET-08-0506) and Program for Chang-
jiang Scholars and Innovative Research Team in the University
(IRT0944).
1H, H-2), 3.83 (dd, 1H, H-3, J = 8.8, 3.3 Hz, H-3), 3.74 (dd, 1H,
J = 11.0, 4.4 Hz, Hsn-3a), 3.58 (dd, 1H, J = 11.0, 5.5 Hz, Hsn-3b), 3.53
(dt, 1H, J = 4.8, 2.2 Hz, H-5), 3.45 (t, J = 9.8 Hz, 1H, H-4),
3.03 (ddd, 1H, J = 14.7, 4.2, 2.6 Hz, H-6b), 2.28–2.32 (m, 4H,
2 ꢂ CO–CH2), 2.24–2.26 (m, 2H, NHCO–CH2), 1.58–1.62 (m, 6H,
3 ꢂ CO–CH2–CH2), 1.23–1.31 (m, 84H, 3 ꢂ CH2–CH2(CH2)14–CH3),
0.88 (t, 9H, J = 7.7 Hz, 3 ꢂ CH3); 13C NMR (150 MHz, CDCl3): d
14.3, 22.9, 25.1, 25.2, 25.9, 29.4–29.9, 32.1, 34.2–34.3, 36.6, 40.0,
62.6, 65.9, 67.1, 69.9, 70.3, 70.6, 71.7, 102.0, 173.4, 173.7, 176.4;
HR-MALDI-MS m/z Calcd for C63H121O10N Na 1074.8888 [M+Na]+,
found 1074.8886.
References
1. Hölzl, G.; Dörmann, P. Prog. Lipid Res. 2007, 46, 225–243.
2. Colombo, D.; Tringali, C.; Franchini, L.; Cirillo, F. Eur. J. Med. Chem. 2011, 46,
1827–1834.
3. Andrianasolo, E. H.; Haramaty, L.; Vardi, A.; White, E.; Lutz, R.; Falkowski, P. J.
Nat. Prod. 2008, 71, 1197–1201.

82
J. Zhang et al. / Carbohydrate Research 381 (2013) 74–82
4. Zhang, H.; Oh, J.; Jang, T.-S.; Min, B. S.; Na, M. Food Chem. 2012, 131, 1097–1103.
26. Fife, T. H.; Bembi, R.; Natarajan, R. J. Am. Chem. Soc. 1996, 118, 12956–12963.
27. Nukada, T.; Berces, A.; Zgierski, M. Z.; Whitfield, D. M. J. Am. Chem. Soc. 1998,
120, 13291–13295.
28. Mydock, L. K.; Demchenko, A. V. Org. Biomol. Chem. 2010, 8(3), 497–510.
29. Gordon, D. M.; Danishefsky, S. J. J. Am. Chem. Soc. 1992, 114, 659–663.
30. Lafont, D.; Carrière, F.; Ferrato, F.; Boullanger, P. Carbohydr. Res. 2006, 341, 695–
704.
31. Dinkelaar, J.; de Jong, A. R.; van Meer, R.; Somers, M.; Lodder, G.; Overkleeft, H.
S.; Codee, J. D. C.; van der Marel, G. A. J. Org. Chem. 2009, 74, 4982–4991.
32. Ayala, L.; Lucero, C. G.; Romero, J. A. C.; Tabacco, S. A.; Woerpel, K. J. Am. Chem.
Soc. 2003, 125, 15521–15528.
33. Chamberland, S.; Ziller, J. W.; Woerpel, K. J. Am. Chem. Soc. 2005, 127, 5322–
5323.
34. Lucero, C. G.; Woerpel, K. J. Org. Chem. 2006, 71, 2641–2647.
35. Yang, M. T.; Woerpel, K. A. J. Org. Chem. 2008, 74, 545–553.
36. Crich, D.; Sun, S. J. Am. Chem. Soc. 1997, 119, 11217–11223.
37. Lahmann, M.; Oscarson, S. Org. Lett. 2000, 2, 3881–3882.
38. Beaver, M. G.; Woerpel, K. J. Org. Chem. 2010, 75, 1107–1118.
39. Krumper, J. R.; Salamant, W. A.; Woerpel, K. A. J. Org. Chem. 2009, 74, 8039–
8050.
40. Baek, J. Y.; Lee, B. Y.; Jo, M. G.; Kim, K. S. J. Am. Chem. Soc. 2009, 131, 17705–
17713.
41. Crich, D.; Vinogradova, O. J. Am. Chem. Soc. 2007, 129, 11756–11765.
42. Ustyuzhanina, N.; Komarova, B.; Zlotina, N.; Krylov, V.; Gerbst, A.; Tsvetkov, Y.;
Nifantiev, N. Synlett 2006, 6, 921.
5. Murakami, C.; Kumagai, T.; Hada, T.; Kanekazu, U.; Nakazawa, S.; Kamisuki, S.;
Maeda, N.; Xu, X.; Yoshida, H.; Sugawara, F. Biochem. Pharmacol. 2003, 65, 259–
267.
6. Ohta, K.; Mizushina, Y.; Hirata, N.; Takemura, M.; Sugawara, F.; Matsukage, A.;
Yoshida, S.; Sakaguchi, K. Chem. Pharm. Bull. 1998, 46, 684–686.
7. Zhou, B.-N.; Tang, S.; Johnson, R. K.; Mattern, M. P.; Lazo, J. S.; Sharlow, E. R.;
Harich, K.; Kingston, D. G. I. Tetrahedron 2005, 61, 883–887.
8. Dai, J. Q.; Zhu, Q. X.; Zhao, C. Y.; Yang, L.; Li, Y. Phytochemistry 2001, 58, 1305–
1309.
9. Mishra, P. K.; Singh, N.; Ahmad, G.; Dube, A.; Maurya, R. Bioorg. Med. Chem. Lett.
2005, 15, 4543–4546.
10. Andersen, R. J.; Taglialatela-Scafati, O. J. Nat. Prod. 2005, 68, 1428–1430.
11. Gupta, P.; Yadav, D. K.; Siripurapu, K. B.; Palit, G.; Maurya, R. J. Nat. Prod. 2007,
70, 1410–1416.
12. Zou, Y.; Li, Y.; Kim, M.-M.; Lee, S.-H.; Kim, S.-K. Biotechnol. Bioprocess Eng. 2009,
14, 20–26.
13. Gollner, C.; Philipp, C.; Dobner, B.; Sippl, W.; Schmidt, M. Carbohydr. Res. 2009,
344(13), 1628–1631.
14. Colombo, D.; Gagliardi, C.; Vetro, M.; Ronchetti, F.; Takasaki, M.; Konoshima, T.;
Suzuki, N.; Tokuda, H. Carbohydr. Res. 2013, 373, 64–74.
15. Sun, Y.; Zhang, J.; Li, C.; Guan, H.; Yu, G. Carbohydr. Res. 2012, 355, 6–12.
16. Wu, H.-J.; Li, C.-X.; Song, G.-P.; Li, Y.-X. Chin. J. Chem. 2008, 26, 1641–1646.
17. Li, C.; Sun, Y.; Zhang, J.; Zhao, Z.; Yu, G.; Guan, H. Carbohydr. Res. 2013, 376, 15–
23.
18. Yewdell, J.; Garcia-Sastre, A. Curr. Opin. Microbiol. 2002, 5, 414–418.
19. Hay, A.; Wolstenholme, A.; Skehel, J.; Smith, M. H. EMBO J. 1985, 4, 3021.
20. Mendel, D. B.; Tai, C. Y.; Escarpe, P. A.; Li, W.; Sidwell, R. W.; Huffman, J. H.;
Sweet, C.; Jakeman, K. J.; Merson, J.; Lacy, S. A. Antimicrob. Agents Chemother.
1998, 42, 640–646.
21. Hayden, F. G.; Pavia, A. T. J. Infect. Dis. 2006, 194, S119–S126.
22. de Souza, L. M.; Sassaki, G. L.; Romanos, M. T. V.; Barreto-Bergter, E. Marine
Drugs 2012, 10(4), 918–931.
43. Kim, K.; Suk, D.-H. Effect of Electron-Withdrawing Protecting Groups at
Remote Positions of Donors on Glycosylation Stereochemistry In Reactivity
Tuning in Oligosaccharide Assembly; Fraser-Reid, B., Cristóbal López, J., Eds.;
Springer: Berlin Heidelberg, 2011; Vol. 301, pp 109–140.
44. Kalikanda, J.; Li, Z. J. Org. Chem. 2011, 76, 5207–5218.
45. Hung, H.-C.; Tseng, C.-P.; Yang, J.-M.; Ju, Y.-W.; Tseng, S.-N.; Chen, Y.-F.; Chao,
Y.-S.; Hsieh, H.-P.; Shih, S.-R.; Hsu, J. T. A. Antiviral Res. 2009, 81, 123–131.
46. Wang, W.; Zhang, P.; Yu, G.-L.; Li, C.-X.; Hao, C.; Qi, X.; Zhang, L.-J.; Guan, H.-S.
Food Chem. 2008, 133, 880–888.
23. Hölzl, G.; Dörmann, P. Prog. Lipid Res. 2007, 46(5), 225–243.
24. Pakkiri, L. S.; Wolucka, B. A.; Lubert, E. J.; Waechter, C. J. Glycobiology 2004,
14(1), 73–81.
25. Goodman, L. Neighboring-Group Participation in Sugars In Advances in
Carbohydrate Chemistry; Melville, L. W., Tipson, R. S., Eds.; Academic Press,
1967; Vol. 22, pp 109–175.