Total synthesis and anticancer activity of highly potent novel glycolipid derivatives

Article abstract of DOI:10.1016/j.ejmech.2009.03.007

The total synthesis and anticancer activity of several novel derivatives based on a dauer effect-inducing glycolipid are presented. A versatile and convergent synthesis was accomplished through stereospecific α-glycosylation, which produced di- and tri-rh

Full text of DOI:10.1016/j.ejmech.2009.03.007

European Journal of Medicinal Chemistry 44 (2009) 3120–3129
Contents lists available at ScienceDirect
European Journal of Medicinal Chemistry
journal homepage: http://www.elsevier.com/locate/ejmech
Original article
Total synthesis and anticancer activity of highly potent novel glycolipid
derivatives
,
a
,
,
Mankil Jung a , Yongnam Lee 1, Hyung-In Moon b 1, Youngae Jung a, Haein Jung a, Miyeon Oh a
*
a Department of Chemistry, Yonsei University, Seoul 120-749, Republic of Korea
b Department of Neuroscience and Inam Neuroscience Research Center, Sanbon Medical Center, Wonkwang University, Kyunggido 435-040, Republic of Korea
a r t i c l e i n f o
a b s t r a c t
Article history:
The total synthesis and anticancer activity of several novel derivatives based on a dauer effect-inducing
glycolipid are presented. A versatile and convergent synthesis was accomplished through stereospecific
Received 14 October 2008
Received in revised form
6 March 2009
Accepted 7 March 2009
Available online 21 March 2009
a-glycosylation, which produced di- and tri-rhamnoside daumone derivatives. Most of the synthetic
derivatives possessed potent anticancer activity against human cancer cell lines. Daumone and deoxy-
rhamnose trisaccharides with amide side chains had the most potent anticancer activity among all other
known glycolipids, with an effective concentration of 20 nM, which is comparable to that of doxorubicin.
Conversely, acyclic and macrocyclic daumone derivatives had drastically decreased anticancer activity.
Due to the high lipophilic nature of the novel glycolipid derivatives, we propose that the observed
anticancer activity is due to their potential to inhibit cell differentiation and proliferation via interaction
with the membranes of cancer cells.
Keywords:
Glycolipid
Total synthesis
Glycosylation
Anticancer activity
Doxorubicin
Ó 2009 Elsevier Masson SAS. All rights reserved.
1. Introduction
potent anticancer activity against human cell lines through
a structure–activity relationship. Diversity in structure based on the
Glycolipids are ubiquitous membrane constituents of animals
and plants that have attracted broad interest in the last few decades
due to their important roles as cell-surface-associated antigens and
recognition factors [1] Glycolipids fractioned from spinach have
been shown to inhibit the activities of replicative DNA polymerase
(pols) and mitochondrial pol [2,3], raising the possibility of using
glycolipids as anticancer chemotherapeutic agents. Due to their
highly lipophilic nature, glycolipids could be further developed into
anticancer drug candidates due to their ability to interact with the
lipid membrane and inhibit cell proliferation [4].
Although some studies have reported interesting glycolipid
anticancer activity, the relatively weak activity of this class of
compounds has generally discouraged further investigation [4–10].
Recently, our laboratory identified a glycolipid (1) as a dauer-
inducing pheromone (dauer: a German word meaning ‘‘enduring’’
and is used to describe an alternative developmental stage of
nematodes) from Caenorhabditis elegans which is able to extend
their lifespan by 10 times [11]. In continuation of the investigation
of additional biological activities of this new glycolipid, we report
a versatile synthesis of novel glycolipid derivatives and study their
daumone will help design to find more potent anticancer glyco-
lipids. A possible mode of action to explain the anticancer activity of
the novel glycolipid derivatives is also proposed.
2. Results and discussion
2.1. Chemistry
In order to investigate the structure–anticancer activity rela-
tionship (SAR) of the lead compound daumone 1, a versatile
synthesis of novel glycolipid derivatives 2–3, 8–10, 14–15, 17, and
20–22 was performed as described in Schemes 1–4. Coupling of the
carboxy group of daumone with diverse functional groups (amines
or alcohols), as well as glycosylation of the 20- and/or 40-hydroxy
groups of 3-deoxy L-rhamnose with a monosaccharide afforded
new glycolipid mono-, di-, and tri-rhamnosides for anticancer
activity testing.
Although some of the glycolipids were prepared in poor yield,
we chose to give priority to the preparation of new compounds;
additional optimization will be performed in due course. First, the
lead glycolipid (1) was prepared as described previously in a 10-
step synthesis beginning with commercially available L-rhamnose
[11]. Coupling of the fatty carboxy group of compound 1 with
various amines (amidation with n-tetradecyl amine, 4-ethylaniline,
* Corresponding author. Tel.: þ82 2 2123 2648; fax: þ82 2 364 7050.
E-mail address: mjung@yonsei.ac.kr (M. Jung).
These authors contributed equally to the work.
1
0223-5234/$ – see front matter Ó 2009 Elsevier Masson SAS. All rights reserved.
doi:10.1016/j.ejmech.2009.03.007

M. Jung et al. / European Journal of Medicinal Chemistry 44 (2009) 3120–3129
3121
OH
OH
R1
O
1
O
10 steps
R1−NH2 or R1−OH
O
5
HO
6
HO
O
O
O
O
a
HO
HO
3
2
OH
OH
4
OH
2a−d
3a−b
L-rhamnose
1
2a R1 = NH-tetradecyl
b R1 = 4-ethylanilinyl
c R1 = {3-(pyrrolidin-2-onyl)}propylaminyl
d R1 = allylpiperazinyl
3a R1 =O−5−hexenyl
b R1 =O−3 -phenoxy benzyl
a
Scheme 1. Synthesis of new derivatives of amides and esters prepared from dauer pheromone 1. Reagents and conditions: (a) amines; (tetradecylamine, 4-ethylaniline, (30-
aminopropyl)-2-pyrrolidinone, or allylpiperazine), alcohols; (5-hexen-1-ol, or 3-phenoxy benzyl alcohol), EDC, HOBt, DMF, room temp., 3–5 h.
(30-aminopropyl)-2-pyrrolidinone, allylpiperazine) and alcohols
(esterification with 5-hexen-1-ol, 3-phenoxy benzyl alcohol)
afforded the amides 2a–d and 3a–b in yields of 55–79% and
30–35%, respectively (Scheme 1). For amidation and esterification
of compound 1, direct coupling without protection of secondary 20
and 40 hydroxyl groups gave amides and esters in the better yields
than with benzoyl protecting groups at 20 and 30 positions.
A versatile and convergent synthesis of di- and tri-rhamnoside
daumone derivatives was accomplished through stereospecific
a-glycosylation via a key step as described in Schemes 2–4.
O
NH
O CCl3
5
6
1
O
TBDMSO
c
O
3
2
+
4
O
O
O
BzO
R2O
5'
6'
1'
O
OBz
OR1
R2O
2'
3'
4'
OR1
5a R1, R2 = Bz
4
a
b
6a R1, R2 = Bz
b R1, R2 = H
b R1, R2 = H
a
c R1=H, R2=TBMDMS
O
O
O
O
O
RO
RO
O
RO
O
d
O
+
+
O
O
O
O
HO
O
O
O
O
O
O
OH
O
O
7a R=TBDMS
7b R=TBDMS
7c R=TBDMS
(36%)
(19%)
(18%)
f
e
e
O
O
O
O
O
RO
RO
O
RO
O
O
O
O
O
O
HO
O
O
O
O
O
O
O
O
OH
8a R=TBDMS
b R=H
9a R=TBDMS
b R=H
10a R=TBDMS
b R=H
g
g
g
Scheme 2. Preparation of novel di-rhamnoside daumone derivatives and their cyclic analogues. a Reagents and conditions: (a) NaOMe, MeOH, 0 ꢀC to room temp., 8 h; (b) TBDMSCl,
imidazole, DMF, room temp., 3 h; (c) BF3–OEt2, CH2Cl2, ꢁ20 ꢀC, 3 h; (d) 4-pentenoic acid, EDC, HOBt, toluene, reflux (110–120 ꢀC), 24 h; (e) (i) Grubbs second-generation Ru cat.,
toluene, reflux (110–120 ꢀC), 20 h; (ii) Pd/C, H2, EtOH, 0 ꢀC, 12 h; (f) Pd/C, H2, EtOAc, 0 ꢀC, 5 h; (g) HF/pyridine, pyridine, room temp., 12 h.

3122
M. Jung et al. / European Journal of Medicinal Chemistry 44 (2009) 3120–3129
NH
OH
O
O
CCl3
O
O
a
+
C6H13
OCH3
O
O
8
BzO
O
RO
OBz
OR
12a R=Bz
b R=H
11
4
b
c
4
O
O
1
5
OR1
6
O
O
O
O
5"
2
O
3
6"
O
+
4
1"
2"
OR
O
O
3"
O
RO
OH
O
4"
5'
RO
6'
1'
2'
OR
O
RO
OR
3'
4'
13a R=Bz, R1=CH3, (78%)
14 R=R1=H
13b R=Bz, (7%)
15 R=H
b
b, d
Scheme 3. Preparation of di- and tri-rhamnoside daumone derivatives with long hydrophobic side chains. a Reagents and conditions: (a) 1 M SnCl4, CH2Cl2, ꢁ78 ꢀC, 5 h; (b) NaOMe,
MeOH, 0 ꢀC to room temp., 8 h; (c) BF3–OEt2, CH2Cl2, ꢁ20 ꢀC, 3 h; (d) (i) NaOMe, MeOH, 0 ꢀC to room temp., 8 h; (ii) 10% NaOH, THF/H2O, room temp., 5 h.
Deprotection (89% yield) at C-2 and C-4 of the known intermediate
5a [11] produced compound 5b, and following regioselective sily-
lation (89%) of the C-4 hydroxyl group of compound 5b with tert-
butyldimethylsilyl chloride in the presence of imidazole in DMF
(room temp.), compound 5c (71%) was produced. Glycosylation of
donor 4 with acceptor 5c was achieved in the presence of BF3–OEt2
[12] in CH2Cl2 at ꢁ20 ꢀC to give disaccharide 6a at a 94% yield with
a natural a-configuration exclusively at C-1 of the known donor 4
[13]. The high stereoselectivity achieved in the glycosylation using
boron trifluoride was attributed to the neighboring group effect of
the C-2 substituent of compound 4 via formation of an acyloxonium
ion with concomitant stabilization of the positive charge on C-1
O
O
O
O
O
4
O
O
O
b
a
O
O
O
O
O
BzO
HO
HO
OBz
OH
HO
OH
O
O
BzO
OBz
5b
OH
16
17
c
d
R1
O
OR
O
O
R1
O
O
O
O
O
O
O
O
O
O
HO
O
O
O
O
R −NH2
HO
1
RO
OH
HO
g
OH
HO
OR
RO
O
O
O
OH
OH
OR
22a R1 = NH-furfuryl
b R1 = 3-bromoanilinyl
c R1 = 4-methylpiperidinyl
18 R=Bz, R1=OH
20 R=H, R1=N3
19 R=H
21 R=CH3
e
f
Scheme 4. Preparation of novel tri-rhamnoside derivatives of pheromone 1. a Reagents and conditions: (a) compound 4, TMSOTf, CH2Cl2, ꢁ20 ꢀC, 5 h; (b) (i) NaOMe, MeOH, 0 ꢀC to
room temp., 8 h; (ii) m-CPBA, CH2Cl2, 0 ꢀC, 24 h; (c) 0.5 M 9-BBN, H2O2, 3 N NaOH, room temp., 2 h; (d) (i) NaIO4, RuCl3$H2O, CH2Cl2/CH3CN/H2O, room temp., 4 h; (ii) NaOMe,
MeOH, 0 ꢀC to room temp., 8 h; (e) (i) TsCl, Et3N, CH2Cl2, 0 ꢀC to room temp., 4 h; (ii) NaN3, DMF, room temp., 8 h; (iii) NaOMe, MeOH, 0 ꢀC to room temp., 8 h; (f) p-TsOH, MeOH,
0
ꢀC, 14 h; (g) amines; (furfurylamine, 3-bromoaniline, or 4-methylpiperidine) EDC, DMAP, DMF, room temp., 24 h.

M. Jung et al. / European Journal of Medicinal Chemistry 44 (2009) 3120–3129
3123
[14a,b]. Structural assignment of the
further confirmed by the chemical shift of the two anomeric
carbons ( 95.5 and 95.0) and lack of coupling contacts of the
anomeric protons ( 4.93 and 4.87) for 6a, in agreement with
a
-
L
-rhamnopyranoside was
of the rhamnose residues with the amines especially in view of the
use of DMAP in the coupling reaction was not detected. Finally,
amidation of unprotected compound 19 cleanly afforded amides,
22a (47% yield), 22b (76% yield), and 22c (58% in yield) (Scheme 4).
d
d
previous findings [15a,b,16]. Selective removal of the benzoate
protecting groups of compound 6a using NaOMe in dry MeOH
afforded compound 6b in excellent yield (93%). Esterification of the
hydroxyl group at C-20 of the di-rhamnoside daumone derivative
6b with 4-pentenoic acid in the presence of EDC and HOBt in
toluene (reflux, 24 h) gave the di-rhamnoside daumone esters 7a
(36%), 7b (19%), and 7c (18%), respectively (Scheme 2). Macro-
cyclization via ring-closing metathesis (RCM) of the separated di-
rhamnoside daumone esters 7a–b in the presence of Grubbs 2nd Ru
reagent [17] successfully afforded novel macrocyclic glycolipids 8a
and 9a in 21% and 15% yields, respectively; these were identified as
potential pharmacophores. Removal of the protective TBDMS group
at C-4 of 8a and 9a by HF/pyridine (pyridine, room temp., 12 h)
cleanly provided 8b (15%) and 9b (12%), respectively. Hydrogena-
tion (Pd/C, H2, EtOAc, 0 ꢀC, 5 h) of all three alkenyl side chains of 7c
gave the hydrogenated di-rhamnoside daumone derivative 10a
(91%), which was subjected to the same deprotection as that of
compound 8a to give 10b (78%) (Scheme 2).
2.2. Anticancer activity (SAR)
The in vitro cytotoxicity of synthetic glycolipids and its related
derivatives against human cancer cells lines of the lung (A549),
ovary (SK-OV-3), brain (XF498), and the colon (HCT15), as well as
a melanoma line (SK-MEL-2) was determined by sulforhodamin B
(SRB) assay [20]. The IC50 values are presented in Table 1.
Most synthetic derivatives of glycolipids possessed potent
anticancer activity against human cancer cell lines. In addition to
extending the lifespan of C. elegans by 10 times, daumone 1
exhibited very strong anticancer activity against human lung
cancer cells, adenocarcinoma cells, and colon carcinoma cells, all of
which were comparable to that of doxorubicin. In addition, dau-
mone 1 was two times more potent than doxorubicin against
human CNS tumors. Further, we determined that the deoxo-
rhamnose sugar moiety on the aliphatic side chain was essential for
tumor-regression activity.
Coupling of the intermediate 4 with the fatty hydroxyester side
long chain 11 afforded compound 12a in a 74% yield. Subsequent
deprotection of C-2, 4 of compound 12a gave monomer 12b in
Derivatization of side chains of compound 1 as amides 2a–d,
and esters 3a–b drastically decreased the anticancer activity
observed above by four to ten times compared to that of daumone
1. Among amide derivatives, aliphatic side chain (2a) or aromatic
a 95% yield (Scheme 3). The
bond in monomer 12a was confirmed by absence of coupling
constant of the anomeric proton at 4.93 and chemical shift of the
anomeric carbons at 95.4. The stereoselective -glycosylation in
a-configuration of the new glycosidic
(2b) moiety enhanced the anticancer activity
3 times than
d
heterocycle moiety (2c, 2d). Cyclic and acyclic di-rhamnoside
daumone derivatives 8b, 9b and 10b, 14, respectively, exhibited
significantly decreased anticancer activity as well. The shapes of the
cyclic derivatives 8b and 9b, with two sugar moieties and rigid
macrocycle were due to the connection of the terminal fatty side
chain, which possibly inhibited the approach of the derivatives into
the putative receptor responsible for the observed inhibition of
cancer cell proliferation, resulting in relatively low activity of the
two cyclic derivatives.
d
a
the presence of BF3–OEt2 (CH2Cl2, ꢁ20 ꢀC, 3 h) at C-4 and C-2 of 12b
with compound 4 afforded the di-rhamnoside daumone derivative
13a (79%) and the tri-rhamnoside derivative 13b (7%), respectively.
Similarly, the a-configuration of 13a and 13b was assigned on the
basis of the lack of a coupling constant of the anomeric proton at dH
4.97, 4.85 (13a), protons dH 5.07, 5.00, 4.92 (13b), and chemical shift
of the anomeric carbons at
d 96.7, 95.4 (13a) and d 96.7, 95.8, 92.9
(13b), respectively. Deprotection of compound 13a using NaOMe in
dry MeOH at 0 ꢀC and then 10% NaOH (THF/H2O, room temp., 8 h)
provided compound 14 in a 51% yield. Deprotection of compound
13b gave 15 in a 64% yield (Scheme 3).
Coupling of glycolipid 5b with excess intermediate 4 in the
presence of TMSOTf at 0 ꢀC afforded trimer 16 in an 85% yield via
Table 1
In vitro anticancer activity of novel glycolipid derivatives 2a–22c.
Compound
IC50
(
m
g/mL)a
SK-OV-3c
A549b
SK-MEL-2d
XF498e
HCT15f
2a
2b
2c
2d
3a
3b
8b
9b
10b
14
15
17
20
21
22a
22b
0.16
0.34
0.76
0.54
0.12
0.24
0.57
0.63
0.78
0.64
0.12
0.76
0.24
0.13
0.08
0.07
0.06
0.03
0.04
0.24
0.24
0.65
0.32
0.31
0.54
0.14
0.73
0.73
0.32
0.24
0.14
0.14
0.14
0.01
0.07
0.03
0.02
0.024
0.11
0.11
0.33
0.53
0.22
0.13
0.44
0.33
0.43
0.33
0.32
0.65
0.33
0.41
0.04
0.09
0.03
0.07
0.015
0.42
0.25
0.25
0.62
0.15
0.52
0.43
0.34
0.45
0.43
0.32
0.65
0.43
0.19
0.07
0.05
0.06
0.09
0.19
0.31
0.2
stereospecific
the fully protected
a lack of a coupling constant of the anomeric proton at
donor) and 4.94 (1H, acceptor). In addition, the three anomeric
carbons of -glycoside 16 were confirmed at 96.0, 94.9, and 93.0,
a
-glycosylation (Scheme 4). The
-glycoside 16 was assigned on the basis of
5.06 (2H,
a-configuration of
a
0.54
0.34
0.12
0.75
0.54
0.65
0.21
0.53
0.1
0.21
0.14
0.21
0.06
0.02
0.02
0.05
0.02
d
a
d
respectively. Deprotection of the O-benzoyl groups of the sugars of
compound 16 with NaOMe in 94% yield and epoxidation with
m-CPBA gave compound 17 in a 50% yield. Oxidative hydroboration
(9-BBN, H2O2/3 N NaOH) of 16 to give hydroxyl 18 in 76% yield,
along with subsequent azidation with NaN3 gave the azide 20 in
a 96% yield (Scheme 4). Compound 21 was prepared from pro-
tected 16 by oxidation of the terminal double bond with NaIO4 and
RuCl3, which gave a 71% yield, and deprotection with NaOMe
following final methylation of compound 19 with p-TsOH gave free
tri-rhamnoside daumone derivative 21 in a 47% yield. Although
amidation of unprotected compound 19 with N,N0-dicyclohex-
ylcarbodiimide (DCC) as a coupling agent in the presence DMAP as
previously reported [18] gave 22a–c in good yields, removal of the
byproduct N,N-dicyclohexylurea (DCU) was difficult. Thus, this
problem was simply resolved by replacement of DCC to 1-ethyl-3-
22c
1 Daumoneg
Doxorubicinh
a
IC50: concentration that produces 50% inhibition of proliferation after 72 h of
incubation.
b
A549: human lung carcinoma (tumor).
c
SK-OV-3: human adenocarcinoma (tumor), malignant ovary ascites.
SK-MEL-2: human malignant melanoma, metastasis to skin of thigh.
XF498: human central nerve system tumor (brain tumor).
HCT15: human colon adenocarcinoma (tumor).
A control material.
d
e
f
(3-dimethylaminopropyl) carbodiimide (EDC) [19] as
a clean
g
h
dehydrating agent with DMAP in DMF (room temp., 24 h). The
possible amidation of the unprotected secondary hydroxyl groups
A standard material.

3124
M. Jung et al. / European Journal of Medicinal Chemistry 44 (2009) 3120–3129
Three novel trisaccharides, deoxyrhamnose derivatives 22a–c of
anticancer activity against human cancer cell lines. Daumone and
its tri-deoxyrhamnose derivatives containing amide side chains
were the most potent anticancer compounds, with effective
concentrations in the nanomolar range, which is comparable to
that of doxorubicin; acyclic and cyclic di-rhamnoside daumone
derivatives exhibited drastically decreased anticancer activity. Due
to the highly lipophilic nature of tri-rhamnoside daumone deriva-
tives of glycolipids, we propose a possible mode of action to explain
the observed anticancer activity, whereby the glycolipids inhibit
cell differentiation and proliferation by interacting with the
membrane of cancer cells.
compound 1 containing an amide side chain, exhibited the most
potent anticancer activity (Table 1), with an effective concentration
of 20 nM, which was comparable to that of doxorubicin in our in
vitro cytotoxicity results against human A549, SK-OV-3, SK-MEL-2,
XF498 and HCT15 cells. Of all known glycolipids, these derivatives
possessed the most potent active anticancer activity in 20 nM
compared with that (IC50 ¼ 7–12
mM against human cancer cells) of
the previously known glycolipids [10]. It is noteworthy that the
aliphatic terminal modification into epoxide 17, azide 20, ester 21 of
side chain of the above mentioned tri-rhamnoside daumone
derivatives significantly decreased, by 5- to 10-fold, the activity of
daumone 1. Since trisaccharides 22a–c with amide side chains were
the most active against human cancer cell lines, we hypothesized
that incorporation of additional saccharide functional groups into
the di-rhamnoside derivatives would further increase the anti-
cancer activity. Although no activity difference was found among
trisaccharide amides (22a–c) with different side chains, the trimers
showed 5–10 times more anticancer activity than that of monomer
amides (2a–d). In general, the presence of the amide bond of the
fatty side chain of 22a–c enhanced the activity while the presence
of a macrocyclic system without amide groups in the cyclic di-
rhamnoside 8 and 9 decreased the anticancer activity. These find-
ings suggest that the amide side chain on the tri-rhamnoside sugars
is the structure principally responsible for establishing the most
active anticancer activity.
4. Experimental section
4.1. Chemistry
All commercial reagents and solvents were used as received
without further purification unless specified. Reaction solvents
were distilled from calcium hydride for dichloromethane and from
sodium metal and benzophenone for tetrahydrofuran. The reac-
tions were monitored and the Rf values were determined using
analytical thin layer chromatography (TLC) with Merck silica gel 60
and F-254 precoated plates (0.25-mm thickness). Spots on the TLC
plates were visualized using ultraviolet light (254 nm) and a basic
potassium permanganate solution or cerium sulfate/ammonium
dimolybdate/sulfuric acid solution followed by heating on a hot
plate. Flash column chromatography was performed with Merck
silica gel 60 (230–400 mesh). 1H NMR spectra were recorded on
Bruker DRX-250 or Bruker DRX-400 NMR spectrometers. Proton
2.3. Mechanism of anticancer activity
Elucidation of the mechanism of anticancer action of these novel
derivatives would help to explain the observed differences in
activity between the structurally diverse derivatives and help guide
the design of more effective anticancer drugs. The glycolipid
derivatives were made to assess their potential to inhibit differ-
entiation and proliferation of cancer cells. It is not known if
glycolipids interact with calmodulin, an intracellular Ca2þ binding
protein, which is essential for cell proliferation [21]. In preliminary
testing, the glycolipid derivatives did not show any histone
deacetylation inhibition activity.
Although details of the mechanism of apoptosis remain unclear,
lipophilicity may play an important role in glycolipid anticancer
activity. The relative lipophilicity of these compounds could obvi-
ously determine the quantities that accumulate in the membrane;
however, since the exposed tri-rhamnoside daumone derivative
backbone with polyhydroxy groups would render the amides 22a–c
more polar than mono- and di-rhamnoside daumone derivatives,
the higher cytotoxicity of compounds 22a–c is probably related to
the extent of incorporation into the membranes of sensitive cells
[10]. The differences in activity of both series of di- and tri-rham-
noside daumone derivatives, particularly from the point of view of
hydrophilicity, could be explained if both series have different
targets or different modes of action [4].
chemical shifts are reported in ppm (
methylsilane (TMS, 0.00) or with the solvent reference relative to
TMS employed as the internal standard (CDCl3, 7.26 ppm; d4-
CD3OD, 3.31 ppm). Data were reported as follows: chemical shift
{multiplicity [singlet (s), doublet (d), triplet (t), quartet (q), and
multiplet (m)], coupling constants [Hz], integration}. 13C NMR
spectra were recorded on Bruker DRX-250 (62.9 MHz) or Bruker
DRX-400 (100.0 MHz) NMR spectrometers with complete proton
d) relative to internal tetra-
d
d
d
decoupling. Carbon chemical shifts were reported in ppm (
relative to TMS with the respective solvent resonance as the
internal standard (CDCl3, 77.0 ppm; d4-CD3OD, 49.0 ppm).
d)
d
d
Infrared (IR) spectra were recorded on a Nicolet Model Impact
FT-IR 400 spectrometer; data are reported in wave numbers
(cmꢁ1). High resolution mass spectrometer (HRMS) analyses were
recorded on an Applied Biosystems 4700 proteomics analyzer
spectrometer. Specific rotations were recorded on a Rudolph AP
III-589 polarimeter.
4.2. General procedure for preparation of daumone esters and
amides (2a–2d and 3a–3b)
A stirred solution of acid 1 (20 mg, 0.07 mmol), HOBt (30 mg,
0.62 mmol), and EDC (45 mg, 0.62 mmol) in DMF (2 mL) was
combined with the appropriate amines (0.08 mmol) (tetradecyl-
amine for compound 2a, 4-ethylaniline for compound 2b, (30-ami-
nopropyl)-2-pyrrolidinone for compound 2c, and allylpiperazine for
compound 2d or alcohols (0.08 mmol) (5-hexen-1-ol for compound
3a, and 3-phenoxy benzyl alcohol for compound 3b) at room
temperature, and the reaction mixture was stirred at same temper-
ature for 3–5 h. The reaction mixture was quenched with slow addi-
tion of saturated citric acid (2 mL), extracted with ethyl acetate
(3 ꢂ 20 mL)andwashedwithbrine(2 ꢂ 10 mL).Theorganiclayerwas
dried over anhydrous MgSO4, filtered, and concentrated under
reduced pressure to give the crude product, which was further puri-
fied by flash silica gel chromatography using hexane/EtOAc/MeOH
The cell-inhibitory profile of the amide-linked glycolipids
strengthens the hypothesis that such glycolipids represent
a distinct group of antitumor amide lipids, having antineoplastic
activities that differ from the well-known alkylphosphocholines
and alkylphospholipids [10].
3. Conclusion
The total synthesis and anticancer activity of novel derivatives
based on dauer effect-inducing glycolipids are presented. A versa-
tile and convergent synthesis was accomplished through stereo-
specific
a-glycosylation to afford both di- and tri-rhamnoside
daumone derivatives. Most synthetic derivatives possessed potent

M. Jung et al. / European Journal of Medicinal Chemistry 44 (2009) 3120–3129
3125
(2a) and CH2Cl2/MeOH (2b–d, and 3a–b) as eluents to afford pure
amide and ester glycolipid derivatives.
3.82–3.77 (m, 2H), 3.72–3.55 (m, 2H), 2.32 (t, 2H, J ¼ 7.3 Hz), 2.10–
2.04 (m, 3H), 1.88–1.78 (m, 1H), 1.68–1.61 (m, 4H), 1.52–1.42 (m,
6H), 1.28 (d, 3H, J ¼ 6.1 Hz), 1.13 (d, 3H, J ¼ 6.1 Hz). 13C NMR
4.2.1. (6R)-(Tetradecyl heptanamide)-3-deoxy-
rhamnopyranoside (2a)
a-L
-
(63 MHz, CDCl3); d 174.1, 138.5, 115.0, 96.0, 77.4, 75.3, 71.1, 70.0,
69.5, 68.3, 64.5, 36.9, 35.4, 34.4, 33.4, 28.2, 25.3, 25.1, 19.0, 17.8; IR
(film) vmax; 3422, 2926, 1730, 1439, 1374, 1240, 1124, 1094, 1042,
978, 908, 779 cmꢁ1; HRMS (FABþ) calcd for C19H34O6 [M þ H]þ m/z,
359.2434; found, 359.2435.
A colorless oil; yield, 79%; Rf ¼ 0.19 (hexane/EtOAc/MeOH,
20
5:5:1); [
d
a]
¼ ꢁ49.1 (c ¼ 1.0, CHCl3); 1H NMR (250 MHz, CDCl3);
D
7.96 (s, 1H, NH) 4.64 (s, 1H), 3.79–3.74 (m, 1H), 3.71 (s, 1H), 3.64–
3.46 (m, 2H), 3.17–3.12 (m, 2H), 2.18 (t, 2H, J ¼ 7.4 Hz), 1.98–1.90 (m,
1H), 1.81–1.70 (m, 1H), 1.64–1.56 (m, 2H), 1.54–1.41 (m, 6H), 1.29 (s,
22H), 1.19 (d, 3H, J ¼ 5.9 Hz), 1.11 (d, 3H, J ¼ 6.1 Hz), 0.92–0.87 (m,
4.2.6. (6R)-(3-Phenoxybenzyl heptanoate)-3-deoxy-
rhamnopyranoside (3b)
a-L-
3H); 13C NMR (63 MHz, CDCl3);
d
176.0, 97.3, 72.1, 71.1, 69.9, 68.3,
A
colorless oil; yield, 30%; Rf ¼ 0.40 (CH2Cl2/MeOH, 9:1);
20
D
38.1, 36.0, 33.1, 30.8, 30.7, 30.5, 30.4, 28.0, 27.1, 26.5, 23.8, 19.3, 18.2,
14.5; IR (film) nmax; 3307, 2925, 2854, 1647, 1554, 1459, 1375, 1250,
1128, 1043, 984 cmꢁ1; HRMS (FABþ) calcd for C27H53NO5 [M þ H]þ
m/z, 472.4002; found, 472.4005.
[a
]
¼ þ65.0 (c ¼ 0.1, MeOH); 1H NMR (250 MHz, CDCl3);
d 7.37–
7.28 (m, 3H), 7.14–6.92 (m, 6H), 5.08 (s, 2H), 4.69 (s, 1H), 3.79–3.70
(m, 2H), 3.68–3.51 (m, 2H), 2.37 (t, 2H, J ¼ 7.3 Hz), 2.08–2.03 (m,
3H), 1.87–1.76 (m, 1H), 1.72–1.61 (m, 2H), 1.55–1.40 (m, 4H), 1.26 (d,
3H, J ¼ 5.9 Hz), 1.11 (d, 3H, J ¼ 6.1 Hz); 13C NMR (63 MHz, MeOD);
4.2.2. (6R)-(4-Ethylanilinyl heptanamide)-3-deoxy-
a-L
-
d 173.7, 157.6, 157.0, 138.1, 130.0, 129.9, 123.6, 122.7, 119.1, 118.4,
rhamnopyranoside (2b)
118.3, 95.9, 71.0, 70.1, 69.3, 68.0, 65.8, 36.8, 35.3, 34.3, 25.3, 24.9,
A
colorless oil; yield, 66%; Rf ¼ 0.28 (CH3Cl/MeOH, 9:1);
19.0, 17.8; IR (film) vmax; 3457, 2927, 2851, 1737, 1579, 1487, 1444,
¼ ꢁ97.0 (c ¼ 0.05, MeOH); 1H NMR (250 MHz, CDCl3);
d
8.08
1380, 1256, 1211, 1159, 1118, 1043, 1026, 983, 692, 604, 493 cmꢁ1
;
20
D
[
a]
(s, 1H, NH), 7.43–7.08 (m, 4H), 4.68 (s, 1H), 3.77–3.70 (m, 2H), 3.66–
3.52 (m, 2H), 3.15 (br s, 2H), 2.62–2.53 (m, 2H), 2.32 (t, 2H,
J ¼ 7.1 Hz), 2.06–2.01 (m, 1H), 1.88–1.78 (m, 1H), 1.70 (m, 2H), 1.46
(m, 4H),1.28–1.15 (m, 6H),1.08 (d, 3H, J ¼ 5.9 Hz). 13C NMR (63 MHz,
HRMS (FABþ) calcd for C26H34O7 [M þ H]þ m/z, 459.2383; found,
459.2381.
4.2.7. (2R)-7-Octenyl-2,4-O-benzoyl-3-deoxy-
a-L-
CDCl3); d 172.0, 140.3, 135.7, 128.3, 120.3, 95.5, 70.6, 69.8, 69.2, 67.9,
rhamnopyranosyl-(1 / 2)-4-O-tert-butyl dimethyl silyl-3-deoxy-
37.6, 36.9, 35.2, 28.3, 25.8, 19.0, 17.9, 15.7; IR (film) vmax; 3419, 2967,
a
-
L
-rhamnopyranoside (6a)
A suspension of trichloroacetimidate glycosyl donor 4 (337 mg,
2931, 1654, 1540, 1455, 1411, 1375, 1310, 1254, 1124, 1027 cmꢁ1
;
HRMS (FABþ) calcd for C21H33NO5 [M]þ m/z, 379.2359; found,
0.672 mmol), glycosyl acceptor 5c (167 mg 0.448 mmol), and 4 Å
molecular sieves (1.5 g) in dry CH2Cl2 (20 mL) was stirred at room
temperature for 30 min. After cooling to ꢁ20 ꢀC, BF3$OEt (0.17 mL)
in dry CH2Cl2 (10 mL) was slowly added drop wise. The resulting
mixture was stirred for 3 h. Saturated aqueous NaHCO3 (20 mL)
was added to quench the reaction. The molecular sieves were
filtered through a Celite pad, and the filtrate was washed with
brine (20 mL), dried over MgSO4, and concentrated under vacuum.
The residue was purified by silica gel flash chromatography
379.2354.
4.2.3. (6R)-(3-(Pyrrolidin-2-onyl)propylaminyl heptanamide)-3-
deoxy-a-L-rhamnopyranoside (2c)
A
colorless oil; yield, 58%; Rf ¼ 0.43 (CH2Cl2/MeOH, 7:1);
20
[
a]
¼ ꢁ33.0 (c ¼ 0.10, MeOH); 1H NMR (250 MHz, MeOH);
d 4.63
D
(s, 1H), 3.81–3.77 (m, 1H), 3.74–3.70 (m, 1H), 3.66–3.53 (m, 2H),
3.51–3.44 (m, 2H), 3.30 (t, 2H, J ¼ 6.8 Hz), 3.15 (t, 2H, J ¼ 6.9 Hz),
2.38 (t, 2H, J ¼ 8.3 Hz), 2.20 (t, 2H, J ¼ 7.5 Hz), 2.08–2.02 (m, 2H),
2.02–1.92 (m, 1H), 1.80–1.69 (m, 3H), 1.66–1.55 (m, 3H), 1.51–1.38
(m, 3H), 1.20 (d, 3H, J ¼ 5.9 Hz), 1.11 (d, 3H, J ¼ 6.1 Hz). 13C NMR
(EtOAc/hexane, 1:6) to provide compound 6a (299 mg, 94%) as
20
a
colorless oil. Rf ¼ 0.39 (hexane/EtOAc, 6:1);
[
a
]
¼ ꢁ37.1
D
(c ¼ 0.52, CHCl3); 1H NMR (250 MHz, CDCl3);
d 8.12 (d, 2H,
(63 MHz, CDCl3);
d
177.8, 176.1, 97.4, 72.2, 71.1, 69.9, 68.3, 48.7, 41.2,
J ¼ 7.3 Hz), 8.05 (d, 2H, J ¼ 7.3 Hz), 7.62–7.57 (m, 2H), 7.50–7.44 (m,
4H), 5.83–5.80 (m, 1H), 5.22 (m, 2H), 5.05–4.93 (m, 3H, C-10), 4.87
(s, 1H, C-1), 4.18-4.14 (m, 1H), 3.83 (br s, 2H), 3.70–3.62 (m, 2H),
2.47–2.41 (m, 1H), 2.33–2.22 (m, 1H), 2.09–2.04 (m, 3H), 1.88–1.79
(m, 1H), 1.60–1.56 (m, 1H), 1.43 (br s, 5H), 1.26 (m, 6H) 1.15 (d, 3H,
J ¼ 6.0 Hz), 0.09 (s, 9H), 0.11 (s, 6H); 13C NMR (63 MHz, CDCl3);
38.1, 37.7, 37.1, 36.0, 32.0, 28.0, 27.0, 26.5, 19.3, 18.8, 18.1; IR (film)
vmax; 3386, 2927, 1649, 1548, 1495, 1467, 1442, 1377, 1292, 1127,
1044, 1029, 984 cmꢁ1; HRMS (FABþ) calcd for C20H36N2O6 [M þ H]þ
m/z, 401.2652; found, 401.2656.
4.2.4. (6R)-(Allylpiperazinyl heptanamide)-3-deoxy-
a-
L
-
d 165.8, 139.0, 133.4, 130.0, 129.9, 129.8, 128.6, 114.5, 95.5, 95.0,
rhamnopyranoside (2d)
76.0, 71.5, 71.0, 70.6, 70.2, 68.8, 67.3, 37.2, 33.9, 29.8, 28.9, 25.4,
19.2, 18.3, 18.1, 18.0, ꢁ4.0, ꢁ4.6; IR (film) nmax; 3066, 2938, 2856,
1719, 1596, 1456, 1386, 1316, 1269, 1159, 1100, 1071, 1024, 884, 832,
779, 715 cmꢁ1; HRMS (FABþ) calcd for C40H58O9Si [M þ H]þ m/z,
711.3928; found, 711.3927.
A
colorless oil; yield, 55%; Rf ¼ 0.42 (CH2Cl2/MeOH, 7:1);
20
D
[
a]
¼ ꢁ84.3 (c ¼ 0.07, MeOH); 1H NMR (250 MHz, CDCl3);
d 5.90–
5.79 (m, 1H), 5.24–5.17 (m, 2H), 4.72 (s, 1H), 3.80–3.62 (m, 4H),
3.62–3.60 (m, 2H), 3.52–3.48 (m, 2H), 3.02 (d, 2H, J ¼ 6.5 Hz), 2.46–
2.30 (m, 6H), 2.12–2.05 (m, 1H), 1.90–1.86 (m, 1H), 1.70–1.56 (m,
2H), 1.51–1.37 (m, 4H), 1.28 (m, 3H), 1.13 (d, 3H, J ¼ 6.0 Hz). 13C NMR
(63 MHz, MeOD);
d
174.0, 136.5, 119.5, 97.4, 72.2, 71.1, 69.9, 68.3,
4.3. General procedure for the deprotection of benzoyl groups (5b,
6b, and 12b)
62.3, 54.1, 53.6, 46.5, 42.4, 38.1, 36.0, 33.9, 26.6, 26.5, 19.3, 18.2; IR
(film) vmax; 3423, 2927, 1738, 1625, 1445, 1240, 1131, 1044, 1029,
985, 919, 448 cmꢁ1; HRMS (FABþ) calcd for C20H36N2O5 [M þ H]þ
m/z, 385.2702; found, 385.2697.
A suspension of protected glycolipids was dissolved in dry
MeOH. After cooling to 0 ꢀC, freshly prepared NaOMe was added.
The resulting mixture was stirred for 8 h, and an acidic ion exchange
resin (Amberlite IR-120) was added for neutralization. The mixture
was stirred for a few minutes and after neutralization (monitored
using pH paper) the resin was filtered off, washed with methanol,
and the filtrate was concentrated under vacuum. The residue was
purified by silica gel flash chromatography (hexane/EtOAc) to
4.2.5. (6R)-(5-Hexenyl heptanoate)-3-deoxy-
rhamnopyranoside (3a)
a-L-
A
colorless oil; yield, 35%; Rf ¼ 0.40 (CH2Cl2/MeOH, 9:1);
20
D
[
a]
¼ ꢁ94.0 (c ¼ 0.05, MeOH); 1H NMR (250 MHz, CDCl3);
d 5.88–
5.72 (m, 1H), 5.05–4.94 (m, 2H), 4.70 (s, 1H), 4.07 (t, 2H, J ¼ 6.6 Hz),

3126
M. Jung et al. / European Journal of Medicinal Chemistry 44 (2009) 3120–3129
provide the pure glycolipid derivative. (See Supplementary mate-
rials for the spectral data).
(40 mg, 0.06 mmol) dissolved in anhydrous pyridine (1 mL). After
24 h of stirring, the resulting mixture was extracted with EtOAc
(3 ꢂ10 mL) and washed with 1 N HCl (3 ꢂ10 mL), saturated
aqueous NaHCO3 (20 mL), and brine (2 ꢂ 10 mL) prior to drying
over MgSO4. After filtration and concentration under reduced
pressure, the residue was purified by silica gel flash chroma-
tography (EtOAc/hexane, 1:2) to provide compound 10b (26 mg,
4.4. Preparation of compounds 8b and 9b via 8a and 9a
To a stirred solution of compound 7a (87 mg, 0.15 mmol) or
compound 7b (106 mg, 0.18 mmol) in anhydrous toluene (40 mL),
Grubbs’
second-generation
catalyst
[((Mes)2Im)(Cy3P)Cl2
78%) as
a
colorless oil. Rf ¼ 0.65 (hexane/EtOAc, 2:1);
-
20
Ru ¼ CHPh] [17] (12 mg) was added in dry toluene, and the solution
was heated to reflux for 20 h. The mixture was then evaporated
under reduced pressure, and Grubbs’ catalyst was removed using
a silica filter. Next, the reaction mixture was dissolved in dry
ethanol (10 mL) and treated with 10% Pd/C (10 mg) under a H2
atmosphere (1 atm) at 0 ꢀC for 2 h. The suspension was then filtered
through a Celite pad, and the filtrate was concentrated under
vacuum. The residue was purified by silica gel flash chromatog-
raphy (EtOAc/hexane, 1:3) to provide compounds 8a (17 mg, 21%)
and 9a (15 mg, 15%) as a colorless oil. Deprotection of the TBDMS
group was achieved by addition of intermediates of compound 8a
(17 mg, 0.03 mmol) or 9a (15 mg, 0.03 mmol) in dry pyridine (1 mL)
[a
]
¼ ꢁ30.9 (c ¼ 0.27, CHCl3); 1H NMR (250 MHz, CDCl3);
d 4.88
D
(s, 1H), 4.79 (br s, 2H), 4.74 (s, 1H), 3.93–3.84 (m, 1H), 3.76 (br s,
2H), 3.71–3.51 (m, 2H), 2.36–2.28 (m, 4H), 2.05–2.00 (m, 3H),
1.76–1.64 (m, 1H), 1.61–1.50 (m, 4H), 1.39–1.24 (m, 14H), 1.15–1.09
(m, 9H), 0.93–0.87 (m, 9H); 13C NMR (63 MHz, CDCl3);
d 173.4,
173.0, 95.3, 94.8, 75.1, 71.6, 70.2, 69.8, 69.6, 68.2, 67.1, 37.3, 34.3,
34.1, 32.5, 31.9, 29.8, 29.4, 27.1, 27.0, 25.8, 22.8, 22.3, 19.1, 17.8,
14.2, 13.8; IR (film) nmax; 3518, 2960, 2931, 2857, 1743, 1463, 1378,
1248, 1173, 1154, 1109, 1032, 986 cmꢁ1; HRMS (FABþ) calcd for
C30H54O9Na [M þ Na]þ m/z, 581.3666; found, 581.3669.
4.4.4. (12R)-Methyl octadecanoate-2,4-di-O-benzoyl-3-deoxy-
a-L-
to a solution of the residue in HF/pyridine (5.5 ml, 0.03 mol). After
rhamnopyranoside (12a)
24 h, the resulting mixture was extracted with EtOAc (3 ꢂ10 mL)
and washed with 1 N HCl (3 ꢂ 10 mL), saturated aqueous NaHCO3
(20 mL) and brine (2 ꢂ 10 mL) prior to drying over MgSO4. After
filtration and concentration under reduced pressure, the residue
was purified by silica gel flash chromatography (EtOAc/hexane, 2:1)
to give compound 8b (10 mg, 15%) or 9b (9 mg, 12%) as colorless
oils.
A suspension of trichloroacetimidate glycosyl donor 4 (498 mg,
0.99 mmol) and glycosyl acceptor 11 (311 mg 0.99 mmol) in dry
CH2Cl2 (10 mL) was stirred at room temperature for 30 min. After
cooling to ꢁ78 ꢀC, 1 M SnCl4 (0.5 mL, 0.50 mmol) was slowly added
drop wise. The resulting mixture was then stirred for 5 h, after
which saturated aqueous NaHCO3 (10 mL) was then added to
quench the reaction, followed by extraction with EtOAc
(3 ꢂ 20 mL). The filtrate was washed with brine (20 mL), dried over
MgSO4, and concentrated under vacuum. The residue was purified
by silica gel flash chromatography (EtOAc/hexane, 1:2) to provide
4.4.1. (11R)-(Undecanoic acid)-3-deoxy-
(1 / 2)-3-deoxy-
Rf ¼ 0.31 (hexane/EtOAc,1:1); [
NMR (250 MHz, CDCl3);
a-L-rhamnopyranosyl-
a-L-rhamnopyranoside-(1,2-lactone) (8b)
20
a
]
¼ ꢁ30.9 (c ¼ 0.53, CHCl3); 1H
12a (479 mg, 74%) as a colorless oil. Rf ¼ 0.49 (hexane/EtOAc, 2:1);
D
20
d
5.20 (s,1H), 4.91 (s,1H), 4.66 (s,1H), 3.83–
[a
]
¼ þ37.6 (c ¼ 0.50, CHCl3); 1H NMR (250 MHz, CDCl3); 8.13–
D
3.77 (m, 2H), 3.70–3.65 (m, 2H), 3.63–3.52 (m, 2H), 2.34–2.30 (m,
2H), 2.03 (br s, 2H), 1.97–1.82 (m, 2H), 1.70–1.60 (m, 2H), 1.28–1.22
8.03 (m, 4H), 7.62–7.56 (m, 2H), 7.50–7.43 (m, 4H), 5.24–5.14 (m,
2H), 4.93 (s, 1H), 4.20–4.13 (m, 1H), 3.66 (br s, 4H), 2.45–2.40 (m,
1H), 2.29 (t, 2H, J ¼ 7.5 Hz), 2.23–2.16 (m, 1H), 1.60–1.52 (m, 6H),
1.30 (br s, 25H), 0.89–0.86 (m, 3H); 13C NMR (63 MHz, CDCl3);
(m, 21H); 13C NMR (63 MHz, CDCl3);
d 174.1, 97.6, 92.0, 79.1, 72.9,
70.7, 69.9, 69.0, 68.3, 35.0, 34.6, 34.3, 32.1, 29.8, 29.5, 29.3, 28.7,
28.2, 25.5, 25.1, 20.8, 18.0; IR (film) nmax; 3417, 2926, 2856, 1736,
1456, 1374, 1246, 1141, 1094, 1048, 1018, 983, 750 cmꢁ1; HRMS
(FABþ) calcd for C23H40O8 [M þ H]þ m/z, 445.2801; found,
445.2793.
d
174.3, 165.9, 165.8, 133.3, 130.2, 130.0, 129.7, 128.6, 95.4, 78.5, 77.4,
71.2, 70.8, 67.1, 51.5, 34.7, 34.2, 33.5, 31.9, 29.8, 29.7, 29.6, 29.4, 29.3,
25.7, 25.1, 25.0, 22.8, 18.0, 14.2; IR (film) nmax; 2926, 2854, 1725,
1452, 1265, 1108, 1069, 1027, 711 cmꢁ1; HRMS (FABþ) calcd for
C39H56O8Na [M þ Na]þ m/z, 675.3873; found, 675.3870.
4.4.2. (11S)-(Undecanoic acid)-3-deoxy-
(1 / 4)-3-deoxy-
Rf ¼ 0.46 (hexane/EtOAc,1:2); [
NMR (250 MHz, CDCl3);
a-L-rhamnopyranosyl-
a-L
-rhamnopyranoside-(1,4-lactone) (9b)
4.4.5. (12R)-Octadecanoic acid-3-deoxy-a-L-rhamnopyranosyl-
20
a]
¼ ꢁ48.6 (c ¼ 0.35, CHCl3); 1H
(1 / 4)-3-deoxy- -rhamnopyranoside (14)
a-L
D
d
4.89–4.84 (m, 1H), 4.78 (d, 2H, J ¼ 2.3 Hz),
Debenzoylation of compound 13a was followed by the general
procedure of deprotection to obtain deprotected glycolipid (94 mg,
54%). Next, the deprotected glycolipid (94 mg, 0.16 mmol) was
dissolved in THF–H2O 1:1 (2 mL). To this solution 10% NaOH
(0.1 mL) was slowly added drop wise and stirred for 4 h. After 4 h,
the mixture was diluted by EtOAc (2 mL) and was stirred with 10%
HCl (2 mL) for 1 h. The organic layers were evaporated under
vacuum. The residue was purified by silica gel flash chromatog-
3.90–3.86 (m, 5H), 3.67–3.58 (m, 1H), 2.35–2.33 (m, 2H), 2.04–1.99
(m, 2H), 1.93–1.89 (m, 2H), 1.65 (br s, 2H), 1.29–1.20 (m, 21H); 13C
NMR (63 MHz, CDCl3);
d 174.1, 94.8, 94.6, 73.2, 71.7, 69.7, 69.1, 67.9,
67.6, 34.9, 34.3, 31.5, 31.0, 28.7, 28.4, 27.6, 24.8, 24.6, 20.4, 18.0, 17.6;
IR (film) nmax; 3437, 2925, 2854, 1738, 1462, 1377, 1247, 1152, 1133,
1112, 1034, 757 cmꢁ1; HRMS (FABþ) calcd for C23H40O8 [M þ H]þ m/
z, 445.2801; found, 445.2800.
raphy (CH2Cl2/MeOH, 7:1) to provide pure compound 14 (47 mg,
20
4.4.3. (2R)-(n-Octane-2-yl)-2,4-di-O-pentanoyl-3-deoxy-
a
-
L
-
51%) as a colorless oil. Rf ¼ 0.33 (CH2Cl2/MeOH, 7:1); [
a
]
D
¼ ꢁ55.1
rhamnopyranosyl-(1 / 2)-3-deoxy-
a
-L
-rhamnopyranoside (10b)
(c ¼ 0.51, CHCl3); 1H NMR (250 MHz, MeOD);
d 4.78 (s, 1H), 4.65 (s,
via (10a)
1H), 3.78–3.77 (m, 2H), 3.65–3.60 (m, 5H), 2.28–2.26 (t, 2H,
J ¼ 7.3 Hz), 2.04–1.99 (m, 2H), 1.98–1.60 (m, 2H), 1.59–1.50 (m, 6H),
1.32 (s, 22H), 1.26–1.20 (m, 6H), 0.91–0.89 (m, 3H); 13C NMR
Compound 7c (43 mg, 0.06 mmol) was dissolved in dry EtOAc
(2 mL) and treated with 10% Pd/C (10 mg) under H2 atmosphere
(1 atm) at 0 ꢀC for 5 h with stirring. The suspension was filtered
through a Celite pad, and the filtrated was concentrated. The
residue was purified by silica gel flash chromatography (EtOAc/
hexane, 1:3) to provide intermediate 10a (40 mg) as a colorless
(63 MHz, MeOD); d 178.1, 99.5, 98.0, 78.5, 75.7, 71.3, 71.2, 69.6, 68.6,
68.2, 35.8, 35.1, 34.6, 33.2, 33.0, 30.8, 30.7, 30.6, 30.4, 30.2, 26.7, 26.1,
26.0, 23.7, 18.2, 18.1, 18.0, 14.4; IR (film) nmax; 3393, 2926, 2856,
1666, 1456, 1334, 1258, 1100, 1042, 978, 832, 674 cmꢁ1; HRMS
(FABþ) calcd for C30H56O9Na [M þ Na]þ m/z, 583.3822; found,
583.3822.
oil. For deprotection of the TBDMS group, HF/pyridine (10.1
0.06 mmol) was added to a solution of the intermediate 10a
ml,

M. Jung et al. / European Journal of Medicinal Chemistry 44 (2009) 3120–3129
3127
4.4.6. (12R)-(Methyloctadecanoate)-3-deoxy-
rhamnopyranosyl-(1 / 2)-3-deoxy- -rhamnopyranosyl-(1 / 4)-
3-deoxy- -rhamnopyranoside (15)
a
-
L
-
quenched by addition of saturated NaHCO3 (10 mL). The mixture
was extracted with CH2Cl2 (3 ꢂ 20 mL) and was washed with
saturated NaHCO3 (20 mL). The organic layer was dried over
MgSO4 and concentrated under vacuum to give crude product,
which was subsequently purified on a silica gel column (CH2Cl2/
a-L
a-L
A suspension of trichloroacetimidate glycosyl donor 4 (190 mg,
0.38 mmol), glycosyl acceptor 12b (169 mg 0.38 mmol), and 4 Å
molecular sieves (1.0 g) in dry CH2Cl2 (10 mL) was stirred at room
MeOH, 7:1) to give compound 17 (25 mg, 50%) as a colorless oil.
20
temperature for 30 min. After cooling to ꢁ78 ꢀC, BF3$OEt (24
m
l,
Rf ¼ 0.30 (CH2Cl2/MeOH, 7:1); [
a
]
D
¼ ꢁ108.6 (c ¼ 0.14, CHCl3); 1H
0.19 mmol) was slowly added drop wise. The resulting mixture was
stirred for 3 h. Saturated aqueous NaHCO3 (20 mL) was then added
to quench the reaction. The molecular sieves were filtered through
a Celite pad, and the filtrate was washed with brine (20 mL), dried
over MgSO4, and concentrated under vacuum. The residue was
purified by silica gel flash chromatography (EtOAc/hexane, 1:2) to
give compounds 13a (235 mg, 79%) and 13b (94 mg, 7%) as colorless
oils, respectively. Debenzoylation of compound 13b by the general
NMR (250 MHz, MeOD); d 4.81 (s, 1H), 4.66 (s, 1H), 4.65 (s, 1H),
3.80–3.71 (m, 5H), 3.58–3.47 (m, 5H), 2.92 (br s, 1H), 2.75–2.72 (t,
1H, J ¼ 4.9 Hz), 2.49–2.46 (m, 1H), 2.27–2.22 (m, 1H), 2.03–1.93 (m,
2H), 1.84–1.65 (m, 3H), 1.63–1.57 (m, 2H), 1.51 (m, 6H), 1.26–1.20
(m, 9H), 1.13 (d, 3H, J ¼ 6.0 Hz); 13C NMR (100 MHz, MeOD)
d 97.5,
94.0, 93.8, 73.3, 70.3, 69.6, 69.1, 69.0, 67.4, 67.3, 66.9, 65.9, 65.8,
51.0, 45.4, 35.9, 33.6, 31.2, 26.9, 24.6, 24.4, 17.0, 16.5, 15.7; IR (film)
nmax; 3413, 2924, 2360, 1731, 1383, 1245, 1124, 1034, 981, 668 cmꢁ1
;
procedure described above gave compound 15 (38 mg, 64%) as
HRMS (FABþ) calcd for C26H46O11 [M þ H]þ m/z, 535.3118; found,
20
a colorless oil. Rf ¼ 0.48 (CH2Cl2/MeOH, 7:1); [
a]
¼ ꢁ83.1 (c ¼ 0.51,
535.3124.
D
CHCl3); 1H NMR (250 MHz, MeOD);
d
4.81 (s, 1H), 4.66 (m, 2H), 3.79
(br s, 3H), 3.72 (br s, 1H), 3.64 (s, 3H), 3.62–3.53 (m, 6H), 2.31 (t, 2H,
J ¼ 7.2 Hz), 2.03–1.94 (m, 3H), 1.85–1.73 (m, 3H), 1.65–1.51 (m, 6H),
1.31 (s, 22H), 1.25–1.20 (m, 9H), 0.90–0.88 (m, 3H); 13C NMR
4.4.9. Preparation of (2R)-(8-azidooctanyl)-3-deoxy-
rhamnopyranosyl-(1 / 4)-3-deoxy- -rhamnopyranosyl-(1 / 2)-
3-deoxy- -rhamnopyranoside (20)
Under nitrogen atmosphere, compound 18 (58 mg,
a-L-
a-L
a-L
(63 MHz, MeOD);
d
176.0, 99.6, 98.1, 96.0, 78.6, 75.2, 71.8, 71.5, 71.4,
a
71.3, 69.7, 69.6, 69.3, 68.2, 68.1, 35.9, 34.8, 34.6, 33.0, 30.7, 30.4, 30.2,
29.1, 26.7, 26.0, 23.7, 18.8, 18.2, 18.1, 14.5; IR (film) nmax; 3418, 2929,
2855, 1741, 1454, 1370, 1251, 1205, 1128, 1105, 1037, 982, 855,
836 cmꢁ1; HRMS (FABþ) calcd for C37H68O12Na [M þ Na]þ m/z,
727.4608; found, 727.4603.
0.06 mmol) in dry CH2Cl2 (2 mL) was added with Et3N (10 mL,
0.07 mmol) and stirred for 10 min at 0 ꢀC followed by addition of
p-toluenesulfonic chloride (18 mg, 0.10 mmol). The reaction
mixture was then stirred for 4 h and quenched with H2O. The
mixture was extracted with EtOAc (3 ꢂ 20 mL) and washed with
brine (2 ꢂ 20 mL). The extract was dried over MgSO4 and
concentrated under vacuum. The residue was purified by a silica
gel column (EtOAc/hexane, 1:4) to provide tosylated glycolipid
(50 mg, 72%) as colorless oil. Next, a solution of tosylated glycolipid
(50 mg, 0.05 mmol) in DMF (2 mL) was stirred at room tempera-
ture with sodium azide (5.8 mg, 0.10 mmol) for 8 h. The mixture
was poured onto water (10 mL), extracted with EtOAc (3 ꢂ 20 mL),
and washed with brine (2 ꢂ 20 mL). After the mixture was
concentrated under vacuum, the residue was purified by silica gel
flash chromatography (EtOAc/hexane, 1:7) to obtain azide glyco-
lipid (40 mg, 90%) as colorless oil. Finally, debenzoylation of the
azide glycolipid (40 mg, 0.05 mmol) by the general procedure
4.4.7. (2R)-7-Octenyl-2,4-di-O-benzoyl-3-deoxy-
rhamnopyranosyl-(1 / 2)-2,4-di-O-benzoyl-3-deoxy-
rhamnopyranosyl-(1 / 4)-3-deoxy- -rhamnopyranoside (16)
a-L-
a-L-
a-L
A suspension of glycosyl donor 4 (1.08 g, 2.16 mmol), glycosyl
acceptor 5b (279 mg, 1.08 mmol), and 4 Å molecular sieves (2 g) in
dry CH2Cl2 (20 mL) was stirred at room temperature for 30 min.
After cooling to ꢁ20 ꢀC, TMSOTf (0.1 mL, 0.54 mmol) was added.
The resulting mixture was then stirred for 5 h and afterwards was
diluted with CH2Cl2 (10 mL). The reaction was quenched by the
addition of saturated aqueous NaHCO3 (20 mL). The molecular
sieves were filtered through a Celite pad. The filtrate was washed
with brine (20 mL), dried over MgSO4, and concentrated under
vacuum. The residue was purified by silica gel flash chromatog-
afforded compound 20 (22 mg, 96%) as a colorless oil. Rf ¼ 0.25
20
(CH2Cl2/MeOH, 10:1); [
a]
¼ ꢁ136.9 (c ¼ 0.79, CDCl3); 1H NMR
D
raphy (EtOAc/hexane, 1:6) to provide compound 16 (858 mg, 85%)
(400 MHz, MeOD); d 4.86 (s, 1H), 4.67 (s, 1H), 4.65 (s, 1H), 3.80–
20
as a colorless oil. Rf ¼ 0.2 (hexane/EtOAc, 6:1); [
a]
¼ ꢁ36.5
3.72 (m, 5H), 3.66–3.49 (m, 4H), 3.34–3.31 (m, 1H), 2.28–2.21 (m,
1H), 2.08–1.94 (m, 3H), 1.84–1.70 (m, 2H), 1.67–1.62 (m, 1H), 1.60–
1.56 (m, 2H), 1.53–1.49 (m, 2H), 1.40–1.38 (m, 5H), 1.29 (s, 2H),
1.25–1.20 (m, 9H), 1.13 (d, 3H J ¼ 6.0 Hz); 13C NMR (100 MHz,
D
(c ¼ 12.33, CHCl3); 1H NMR (250 MHz, CDCl3);
d 8.14–8.10 (m, 2H),
8.08–7.99 (m, 6H), 7.62–7.54 (m, 4H), 7.49–7.40 (m, 8H), 5.93–5.76
(m, 1H), 5.30–5.15 (m, 4H), 5.06 (br s, 2H), 5.00–4.99 (m, 2H), 4.94
(s, 1H), 4.24–4.08 (m, 2H), 3.95–3.72 (m, 4H), 2.45–2.39 (m, 2H),
2.33–2.19 (m, 2H), 2.14–2.09 (m, 2H), 1.92–1.72 (m, 2H), 1.65–1.47
(m, 6H), 1.42 (d, 3H, J ¼ 6.0 Hz), 1.33 (d, 3H, J ¼ 6.2 Hz), 1.30 (d, 3H,
J ¼ 6.2 Hz), 1.17 (d, 3H, J ¼ 6.0 Hz); 13C NMR (63 MHz, CDCl3);
MeOD); d 99.8, 96.3, 96.0, 75.7, 72.7, 71.9, 71.5, 71.3, 69.7, 69.6, 69.2,
68.2, 68.1, 53.9, 38.1, 35.9, 30.2, 29.9, 29.2, 27.8, 26.8, 19.4, 18.8, 18.1;
IR (film) nmax; 3319, 2931, 2857, 2095, 1735, 1654, 1455, 1374, 1248,
1128, 1037, 983 cmꢁ1; HRMS calcd for C26H47N3O10 [M]þ m/z,
561.3261; found, 561.3244.
d
179.2, 165.8, 165.7, 139.0, 133.3, 130.0, 129.9, 129.7, 128.5, 114.5,
96.0, 94.9, 93.0, 75.5, 72.4, 71.7, 71.0, 70.9, 70.5, 67.8, 67.5, 67.4, 37.0,
33.8, 29.7, 29.6, 28.9, 25.3, 19.1, 18.6, 17.9, 14.3; IR (film) nmax; 3248,
1723, 1625, 1401, 1266, 1098, 1053, 1029, 767, 706 cmꢁ1; HRMS
(FABþ) calcd for C54H62O14Na [M þ Na]þ m/z, 957.4037; found,
957.4031.
4.4.10. (6R)-(Methylheptanoate)-3-deoxy-
(1 / 4)-3-deoxy- -rhamnopyranosyl-(1 / 2)-3-deoxy-
rhamnopyranoside (21)
A suspension of compound 19 (53 mg, 0.10 mmol) and p-TsOH
(2 mg, 0.01 mmol) in dry MeOH (3 mL) was stirred for 14 h at 0 ꢀC.
The mixture was quenched by H2O (10 mL), extracted with EtOAc
(3 ꢂ 20 mL), and washed with brine (2 ꢂ 20 mL). The organic layer
was separated and dried over MgSO4 and concentrated under
vacuum. The residue was purified by silica gel flash chromatog-
a-L-rhamnopyranosyl-
a-L
a-L-
4.4.8. (2R)-[(6-Oxiran-2-yl)hexan-2-yloxy]-3-deoxy-
rhamnopyranosyl-(1 / 4)-3-deoxy- -rhamnopyranosyl-(1 / 2)-
3-deoxy- -rhamnopyranoside (17)
a-L-
a-L
a-L
Debenzoylation of protected compound 16 (94 mg, 0.10 mmol) by
the general procedure gave the deprotected glycolipid (48 mg, 94%)
as a colorless oil. The debenzoylated glycolipid (48 mg, 0.10 mmol)
and m-CPBA (32 mg, 0.20 mmol) were then dissolved in dry CH2Cl2
(3 mL) at 0 ꢀC. The reaction mixture was then stirred for 24 h and
raphy (CH2Cl2/MeOH, 7:1) to afford compound 21 (26 mg, 47%) as
20
colorless oil. Rf ¼ 0.20 (CH2Cl2/MeOH, 7:1); [
CHCl3); 1H NMR (400 MHz, MeOD);
(s, 1H), 3.80–3.71 (m, 5H), 3.65 (s, 3H), 3.64–3.48 (m, 5H), 2.34 (t,
a
]
¼ ꢁ138.9 (c ¼ 0.80,
D
d
4.85 (s, 1H), 4.67 (s, 1H), 4.65

3128
M. Jung et al. / European Journal of Medicinal Chemistry 44 (2009) 3120–3129
2H, J ¼ 7.6 Hz), 2.26–2.23 (m, 1H), 2.04–1.94 (m, 2H), 1.93–1.68 (m,
67.4, 67.0, 66.8, 66.0, 65.9, 45.2, 41.1, 33.7, 32.8, 31.8, 30.0, 29.4, 27.9,
26.9, 24.5, 24.3, 19.8,17.1, 16.6,15.8; IR (film) nmax; 3364, 2955, 2924,
2849, 1726, 1620, 1451, 1384, 1123, 1040, 984 cmꢁ1; HRMS (FABþ)
calcd for C31H55NO11 [M]þ m/z, 617.3775; found, 617.3705.
3H), 1.65–1.61 (m, 2H), 1.59–1.39 (m, 4H), 1.25–1.20 (m, 9H), 1.13 (d,
3H, J ¼ 6.0 Hz); 13C NMR (100 MHz, MeOD);
d 175.8, 99.8, 96.4, 96.0,
75.7, 72.6, 71.9, 71.5, 71.3, 69.7, 69.6, 69.3, 68.2, 68.1, 52.0, 37.9, 35.9,
34.8, 29.2, 26.4, 25.9, 19.4, 18.8, 18.1; IR (film) nmax; 3427, 1733,1653,
1375, 1038, 983 cmꢁ1
;
HRMS (FABþ) calcd for C26H46O12Na
4.6. Measurement of anticancer activity
[M þ Na]þ m/z, 573.2887; found, 573.2895.
Human cancer cell lines of the lung (A549), ovary (SK-OV-3),
brain (XF498), and the colon (HCT15), as well as melanoma cancer
cells (SK-MEL-2), were used for in vitro cytotoxicity testing using
the SRB (sulforhodamin B) assay [20]. The cells were maintained as
stocks in RPMI 1640 (Gibco) supplemented with 10% fetal bovine
serum (Gibco). Cell cultures were passaged once or twice weekly by
using trypsin–EDTA to detach the cells from their culture flasks. The
rapidly growing cells were harvested, counted, and incubated at the
appropriate concentration (1–2 ꢂ104 cells/well) in 96-well plates.
After incubation for 24 h, the compounds were dissolved in culture
medium, applied to the culture wells in triplicate, and incubated for
48 h at 37 ꢀC under a 5% CO2/95% air atmosphere in a humidified
incubator. The cultured cells were fixed with 10% cold TCA and
stained with 0.4% SRB dissolved in 1% acetic acid. After solubilizing
the bound stain with 10 mM unbuffered Trisma base solution (pH
10.5) using a gyratory shaker, the absorbance at 520 nm was
measured spectrophotometrically in a microplate reader. Cytotoxic
activity was evaluated by determining the concentration of
compound that was required to inhibit protein synthesis by 50%
(IC50); activities were compared with that of doxorubicin in the
same assay.
4.5. General procedure for the amide glycolipids (22a, 22b and 22c)
To a solution of acid glycolipid 19 (15 mg, 0.028 mmol) and
DMAP (3.3 mg, 0.028 mmol) in DMF (2 mL), either furfurylamine
(2.70 mg, 0.028 mmol), 3-bromoaniline (4.78 mg, 0.028 mmol) or
4-methylpiperidine (2.76 mg, 0.028 mmol), was added at room
temperature. After stirring for 10 min, EDC (5.33 mg, 0.028 mmol)
was added drop wise to the mixture. The reaction was stirred for
24 h, and concentrated under vacuum. Purification of this residue
by silica gel flash chromatography (CH2Cl2/MeOH, 7/1–4/1) affor-
ded compounds 22a (8 mg, 47%), 22b (10 mg, 76%) or 22c (9.8 mg,
58%), respectively, all as colorless oils.
4.5.1. (6R)-(Furfurylheptanamide)-3-deoxy-a-L-rhamnopyranosyl-
(1 / 4)-3-deoxy- -rhamnopyranosyl-(1 / 2)-3-deoxy-a-L-
a-L
rhamnopyranoside (22a)
20
Rf ¼ 0.53 (CH2Cl2/MeOH, 7:1); [
a]
D
¼ ꢁ40.2 (c ¼ 0.23, CHCl3); 1H
NMR (400 MHz, MeOD);
d
7.41 (d, 1H, J ¼ 1.6 Hz), 6.34–6.33 (dd, 1H,
J ¼ 2.0, 1.6 Hz), 6.23–6.22 (d, 1H, J ¼ 3.2 Hz), 4.85 (s, 1H), 4.66 (s, 1H),
4.65 (s, 1H), 4.34 (s, 2H), 3.79–3.71 (m, 5H), 3.64–3.52 (m, 5H), 2.25
(m, 1H), 2.24–2.20 (t, 2H, J ¼ 7.2 Hz), 1.95–1.94 (m, 2H), 1.84–1.69
(m, 3H), 1.65–1.62 (m, 2H), 1.55–1.37 (m, 4H), 1.24–1.20 (m, 9H), 1.12
Acknowledgments
(d, 3H, J ¼ 6.0 Hz); 13C NMR (100 MHz, MeOD);
d 176.0, 143.3, 111.4,
108.1, 99.8, 96.4, 96.1, 79.5, 75.7, 72.8, 71.9, 71.5, 71.4, 69.7, 69.3,
68.3, 68.2, 38.0, 37.1, 36.8, 35.9, 30.7, 29.2, 26.9, 26.4, 19.4, 18.9, 18.1;
IR (film) nmax; 3424, 2923, 2852, 1872, 1738, 1650, 1537, 1453, 1377,
1255,1126,1034, 981, 752 cmꢁ1; HRMS (FABþ) calcd for C30H49NO12
[M þ H]þ m/z, 616.3333; found, 616.3330.
This work was supported by the Korean Research Foundation
Grant funded by the Korean Government (MOEHRD, Basic Research
Promotion Fund) (KRF-2006-312-C00267). Y.L., H.J. and M.O.
appreciate the fellowship of the BK21 program from the Ministry of
Education and Human Resources Development.
4.5.2. (6R)-(3-Bromoanilinylheptanamide)-3-deoxy-a-L-
Appendix. Supplementary data
rhamnopyranosyl-(1 / 4)-3-deoxy-
3-deoxy- -rhamnopyranoside (22b)
Rf ¼ 0.58 (CH2Cl2/MeOH, 7:1); [
NMR (400 MHz, MeOD);
a
-
L
-rhamnopyranosyl-(1 / 2)-
a-L
20
a
]
D
¼ ꢁ25.8 (c ¼ 0.24, CHCl3); 1H
General procedure and spectral data of compounds, 5b–c, 6b,
7a–c, 8a, 9a,10a,12b,13a–b,18,19, and 20. This material is available
online at www.sciencedirect.com. Supplementary data associated
with this article can be found in the online version, at doi:10.1016/j.
ejmech.2009.03.007.
d
8.13 (s, 1H, NH), 7.89 (s, 1H), 7.46–7.45
(m, 1H), 7.22–7.20 (m, 2H), 4.85 (s, 1H), 4.65 (s, 1H), 4.64 (s, 1H),
3.79–3.69 (m, 5H), 3.65–3.52 (m, 5H), 2.39 (t, 2H, J ¼ 7.6 Hz), 2.24–
2.21 (m, 1H), 1.97–1.93 (m, 2H), 1.83–1.68 (m, 3H), 1.63–1.60 (m,
2H), 1.57–1.46 (m, 4H), 1.26–1.19 (m, 9H), 1.15–1.13 (d, 3H,
J ¼ 6.0 Hz); 13C NMR (100 MHz, MeOD);
d 174.7, 141.5, 131.4, 127.8,
References
123.8, 123.3, 119.5, 99.8, 96.4, 96.0, 75.7, 72.8, 71.9, 71.5, 71.4, 69.7,
69.3, 68.3, 68.1, 38.1, 37.8, 35.9, 29.2, 26.7, 26.5, 19.4, 18.8, 18.1, 18.0;
IR (film) nmax; 3300, 2924, 2851, 2804, 1822, 1737, 1666, 1589, 1528,
1455, 1374, 1247, 1127, 1104, 1035, 983, 751 cmꢁ1; HRMS (FABþ)
calcd for C31H48BrNO11Na [M þ Na]þ m/z, 712.2308; found,
712.2307.
[1] J. Inokuchi, K. Momosaki, H. Shimeno, A. Nagamatsu, N.S. Radin, J. Cell. Physiol.
141 (1989) 573–583.
[2] A. Kornberg, T.A. Baker, DNA Replication, second ed. W.H. Freeman, New York,
1992, pp. 197–225.
[3] N. Maeda, Y. Kokai, S. Ohtani, H. Sahara, T. Hada, C. Ishimaru, I. Kuriyama,
Y. Yonezawa, H. Iijima, H. Yoshida, N. Sato, Y. Mizushina, Nutr. Cancer 57
(2007) 216–223.
[4] S. Adams, F. Kaufmann, Chem. Phys. Lipids 59 (1991) 255–262.
[5] M. Akira, K. Koshimizu, H. Ohigashi, Bioindustry 13 (1996) 28–34.
[6] V.I. Gorbach, I.N. Krasikova, P.A. Lukyanov, Y.N. Loenko, T.F. Soloveva,
Y.S. Ovodov, V.V. Deev, A.A. Pimenov, Carbohydr. Res. 260 (1994) 73–82.
[7] Z. Reggiardo, Infect. Immun. 21 (1978) 914–917.
[8] K. Amano, E. Ribi, J.L. Cantrell, J. Biochem. 93 (1983) 1391–1399.
[9] T. Kusama, T. Soga, E. Shioya, K. Nakayama, H. Nakajima, Y. Osada, Y. Ono,
S. Kusumoto, T. Shiba, Chem. Pharm. Bull. 38 (1990) 3366–3372.
[10] R.K. Erukulla, X. Zhou, P. Samadder, G. Arthur, R. Bittman, J. Med. Chem. 39
(1996) 1545–1548.
4.5.3. (6R)-(4-Methylpiperidinyl heptanamide)-3-deoxy-
rhamnopyranosyl-(1 / 4)-3-deoxy- -rhamnopyranosyl-(1 / 2)-
3-deoxy- -rhamnopyranoside (22c)
Rf ¼ 0.61 (CH2Cl2/MeOH, 4:1); [
1H NMR (400 MHz, MeOD)
4.86 (s, 1H), 4.67 (s, 1H), 4.65 (s, 1H),
a-L-
a-L
a-L
20
a
]
¼ ꢁ120.8 (c ¼ 0.16, CHCl3);
D
d
4.50 (d, 1H, J ¼ 13.2 Hz), 3.94 (d, 1H, J ¼ 12.8 Hz), 3.80–3.71 (m, 5H),
3.66–3.52 (m, 5H), 3.08 (t, 1H, J ¼ 10.0 Hz), 2.60 (t, 1H, J ¼ 12 Hz),
2.40 (t, 2H, J ¼ 7.2 Hz), 2.27–2.22 (m, 1H), 1.98–1.90 (m, 2H), 1.84–
1.70 (m, 3H), 1.66–1.57 (m, 5H), 1.56–1.28 (m, 6H), 1.25–1.20 (m,
9H), 1.13 (d, 3H, J ¼ 6.4 Hz), 0.96 (d, 3H, J ¼ 6.4 Hz); 13C NMR
[11] Y. P-Jeong, M. Jung, Y.-H. Yim, H. Kim, M. Park, E. Hong, W. Lee, Y.H. Kim,
K. Kim, Y.-K. Paik, Nature 433 (2005) 541–545.
[12] S.A. King, B. Pipik, A.S. Thompson, A. DeCamp, T.R. Verhoeven, Tetrahedron
Lett. 36 (1995) 4563–4566.
(100 MHz, MeOD);
d
171.5, 97.5, 94.1, 93.8, 73.4, 69.7, 69.2, 69.1, 67.5,
[13] L.D. Liu, H.W. Liu, Tetrahedron Lett. 32 (1989) 3353–3356.

M. Jung et al. / European Journal of Medicinal Chemistry 44 (2009) 3120–3129
3129
[14] (a) A. Rencurosi, L.I. Lay, G. Russo, E. Caneva, L. Poletti, J. Org. Chem. 70 (2005)
7765–7768;
[20] (a) P. Skehan, R. Streng, D. Scudiero, A. Monks, J.B. McMahon, D.T. Vistica,
J.T. Warren, H. Bokesc, S. Kenney, M.R. Boyd, J. Natl. Cancer Inst. 82 (1990)
1107–1112;
(b) A.K. Pathak, Y.A. El-Kattan, N. Bansal, J.A. Maddry, R.C. Reynolds, Tetrahe-
dron Lett. 39 (1998) 1497–1500.
[15] (a) A.P. Rauter, S. Lucas, T. Almeida, D. Sacoto, V. Ribeiro, J. Justino, A. Neves,
F.V.M. Silva, M.C. Oliveira, M.J. Ferreira, M.-S. Santos, E. Barbosa, Carbohydr.
Res. 340 (2005) 191–201;
(b) L.V. Rubinstein, R.H. Shoemaker, K.D. Paull, R.M. Simon, S. Tosini,
P. Skehan, D. Scudiero, A. Monks, M.R. Boyd, J. Natl. Cancer Inst. 82 (1990)
1113–1117.
[21] H. Nishino, A. Nishino, J. Takajasu, T. Hasegawa, A. Iwashima, K. Hirabayashi,
S. Iwata, S. Shibata, Cancer Res. 48 (1988) 5210–5215.
(b) F.V.M. Silva, M. Goulart, J. Justino, A. Neves, F. Santos, J. Caio, S. Lucas,
A. Newton, D. Sacoto, E. Barbosa, M.-S. Santos, A.P. Rauter, Bioorg. Med. Chem.
16 (2008) 4083–4092.
Abbreviations
[16] R.J. Ferrier, Adv. Carbohydr. Chem. Biochem. 24 (1969) 199–266.
[17] M. Scholl, S. Ding, C.W. Lee, R.H. Grubbs, Org. Lett. 1 (1999) 953–956.
[18] B. Neises, W. Steglich, Angew. Chem. Int. Ed. 17 (1978) 522–524.
[19] (a) M.K. Dhaon, R.K. Olsen, K. Ramasamy, J. Org. Chem. 47 (1982) 1962–1965;
(b) G. Pickaert, M. Cesario, R. Ziessel, J. Org. Chem. 69 (2004) 5335–5341.
Bz: Benzoyl
SRB: sulforhodamin B
SAR: structure–anticancer activity relationship