Synthesis and antitumor activity of lapathoside D and its analogs

Article abstract of DOI:10.1016/j.ejmech.2012.02.032

Phenylpropanoid sucrose esters are important class of plant-derived natural products and have greater potential to be leads for new drugs because of their structural diversity and broad-array of pharmacological and biological activities. Regio- and chemo-

Full text of DOI:10.1016/j.ejmech.2012.02.032

European Journal of Medicinal Chemistry 53 (2012) 1e12
Contents lists available at SciVerse ScienceDirect
European Journal of Medicinal Chemistry
journal homepage: http://www.elsevier.com/locate/ejmech
Original article
Synthesis and antitumor activity of lapathoside D and its analogs
Parthasarathi Panda a, Manjuvani Appalashetti a, Meenubharathi Natarajan b, Mary B. Chan-Park a,
,
Subbu S. Venkatraman b, Zaher M.A. Judeh a
*
a School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, N1.2-B1-14, Singapore 637459, Singapore
b School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, N4.1-02-06, Singapore 639798, Singapore
a r t i c l e i n f o
a b s t r a c t
Article history:
Phenylpropanoid sucrose esters are important class of plant-derived natural products and have greater
potential to be leads for new drugs because of their structural diversity and broad-array of pharmaco-
logical and biological activities. Regio- and chemo-selective acylation of 2,10:4,6-O-di-isopropylidene
sucrose 4 with cinnamoyl chloride 5 and p-acetoxycinnamoyl chloride 6 afforded mono-, di-, tri- and
tetra- variant PSEs in moderate yields. The first total synthesis of di-substituted PSE, lapathoside D 10 has
been achieved successfully in short and simple synthetic steps from sucrose 3 as an inexpensive starting
material. Lapathoside D 1 and a set of selected synthesized PSEs were tested for in vitro cytotoxicity
against human cervical epithelioid carcinoma (HeLa) cell lines. Most of the compounds exhibited
Received 13 December 2011
Accepted 19 February 2012
Available online 28 March 2012
Keywords:
Phenylpropanoid sucrose esters
Lapathoside D
Regioselective acylation
Di-O-isopropylidene acetal
Antitumor activity
HeLa cell lines
significant antitumor activity with their IC50 values ranging from 0.05 to 7.63 mM. The primary screening
results indicated that PSEs might be valuable source for new potent anticancer drug candidates.
Ó 2012 Elsevier Masson SAS. All rights reserved.
1. Introduction
tetradecanoylphorbol-13-acetate (TPA) in Raji cells [6,8]. It also
exhibited significant potent antioxidant and a-glucosidase inhibi-
Cancer is a leading cause of death in the human population and
is a huge health problem. Therefore, the search for efficient anti-
cancer agents with minimum side effects is a significant research
area. It is well established that natural products provide the most
prolific source of new anticancer lead compounds/drugs [1e3].
During the past 3-4 decades, approximately 150 phenylpropanoid
sucrose esters (PSEs) with the general structure shown in Fig. 1,
have been isolated from various medicinal plant species of the
families Arecaceae, Brassicaceae, Liliaceae, Polygonaceae, Poly-
galaceae, Rosaceae and Smilacaeae whose extracts have been used
worldwide in various traditional and folk medicines [4]. The natural
PSEs such as heloniosides, lapathosides, hydropiperoside, smila-
sides and vanicosides were reported to have antitumor activities
against different human cancer cell lines [4]. The antitumor activ-
ities are said to be mediated by the free hydroxyl, phenol and
acetate groups attached to the sucrose core of the PSEs [5e7].
Lapathoside D 1 (Fig. 1), a typical PSE, isolated from vari-
ous Polygonaceous plant species such as Polygonum lapathifolium,
Polygonum sachalinensis and Polygonum Perfoliatum [8e10]
displayed inhibitory effects on the EpsteineBarr virus early
antigen (EBV-EA) activation by tumor-promoters such as 12-O-
tory activities [10].
Interestingly, PSEs as lead compounds are completely unex-
plored in drug discovery and, with the exception of niruriside 2
[11,12] (Fig. 1), have not been chemically synthesized to date. In
addition, very little work has been done concerning their mecha-
nism of action and structure activity relationship (SAR). Intrigued
by their remarkable therapeutic intervention in a wide range of
diseases and motivated by the abundance of these compounds in
nature, we became interested in developing a general synthetic
strategy that can be utilized for the synthesis of natural and
unnatural PSEs with the aim of studying their antitumor activity.
Herein, we wish to present a general synthetic method for the
synthesis of PSEs demonstrated by the first total synthesis of
lapathoside D 1 and its analogs. In addition, we also report the
in vitro antitumor activity of the synthesized compounds.
2. Results and discussion
2.1. Chemistry
Sucrose is the core structural moiety of all PSEs (Fig. 1). It has
been well established that reactions of native sucrose are complex
since regio- and chemo-selection between the eight hydroxyl
groups is poor [13,14]. To reduce the complexity of the reaction
products, protection/deprotection methodologies are usually
* Corresponding author. Tel.: þ65 6790 6738; fax: þ65 67947553.
E-mail address: zaher@ntu.edu.sg (Z.M.A. Judeh).
0223-5234/$ e see front matter Ó 2012 Elsevier Masson SAS. All rights reserved.
doi:10.1016/j.ejmech.2012.02.032

2
P. Panda et al. / European Journal of Medicinal Chemistry 53 (2012) 1e12
OR6
O
OAc
O
OH
O
6
OAc
O
OH
O
4
OR1'
O
R4O
AcO
HO
HO
HO
1'
R3O
O
O
O
O
OH
2
3
R4'O
R2O
HO
HO
AcO
HO
O
2'
3'
O
O
6'
OR6'
O
OR3'
O
O
O
O
OH
At least one R =
General structure of PSEs
Lapathoside D 1
Fig. 1. General structure of PSEs, lapathoside D 1 and niruriside 2.
Niruriside 2
followed. To this end, 2,10:4,6-di-O-isopropylidene sucrose 4 (4 OH
groups are protected, Scheme 1) has served as a viable substrate for
the synthesis of various sucrose esters and, therefore, was chosen
as the starting material for the synthesis of lapathoside D 1 and its
analogs [15e19]. Moreover, the reactivity as well as selectivity of
the remaining free OH groups of di-O-isopropylidene 4 in the
acylation (e.g. benzoylation) and alkylation reactions were reported
[14,20]. In our synthetic strategy, we anticipated that acylation of
di-O-isopropylidene 4 with suitable acid chlorides should give
access to the acylated sucrose derivatives that can be utilized for
the synthesis of lapathoside D 1 and its analogs (Scheme 1).
Initially, we decided to examine the feasibility of this strategy using
simple acid chloride such as cinnamoyl chloride 5 to avoid
complications due to substituents at the aromatic ring. It is worth
noting that with the exception of niruriside 2, all the reported
natural PSEs have their phenyl rings substituted with either eOH,
-OMe or combination of these substituents.
At the outset, acetonation of sucrose 3 to the required di-O-
isopropylidene sucrose [15,17,21e27] 4 was successfully accom-
plished using 2-methoxypropene (4.5 equiv) according to the
procedure reported by Poschalko et al. [28] (Scheme 1). However, in
this method, purification of di-O-isopropylidene 4 relied on column
chromatography followed by acetylation with excess Ac2O,
recrystallization and deacetylation [28]. This sequence proved to be
tedious, time consuming, low yielding and problematic especially
for large scale. We therefore looked for an alternative purification
route that is simple and amenable for large scale. In our modified
purification route, the crude syrupy product obtained from the
reaction was initially subjected to flash column chromatography to
remove the non-polar impurities. The more polar fractions were
recrystallized using EtOAc to give di-O-isopropylidene 4 as white
solid in 56% yield leaving behind various by-products in the solvent.
This route was extremely suitable and convenient for large scale
purification (ca 200e300 g).
2.1.1. Regio- and chemo-selective acylation of di-O-isopropylidene 4
with cinnamoyl chloride 5
Since di-O-isopropylidene 4 has four free OH groups, it is
expected that a product distribution will be obtained when it is
reacted with cinnamoyl chloride 5. The free OH groups, like the
parent sucrose 3, were anticipated to have slight differences in their
reactivities and selectivities. However, the most pronounced
difference is expected to be between the primary 60-OH and the rest
of the secondary 3-OH, 30-OH and 40-OH. In order to explore these
differences, regio- and chemo-selective acylation of di-O-iso-
propylidene 4 with cinnamoyl chloride 5 was studied under
different reaction conditions (Table 1). When di-O-isopropylidene 4
was reacted with 1.1 equiv of acid chloride 5 (Table 1, entry 1),
O
Cl
X
OH
OMe
O
R3O
R3'O
O
O
O
O
HO
5: X = H
O
O
O
OH
O
p -TsOH
6: X = OAc
OR6'
O
HO
HO
OH
HO
R4'O
O
HO
O
HO
HO
dry DMF,
dry pyridine,
O
O
O
O
70 oC, 55 min
0oC-rt or 50 o
C
OH
O
OH
3
4
7-16
R3
R3'
R6'
R4'
Compound
O
O
7
H
H
H
Cinn
Cinn =
8
9
H
H
Cinn
Cinn
H
H
H
Cinn
10
11
12
13
H
Cinn
H
Cinn
Cinn
H
Cinn
Cinn
H
Cinn
Cinn
CoumAc =
AcO
CoumAc
H
CoumAc
CoumAc
H
H
14
15
H
CoumAc
H
H
CoumAc CoumAc CoumAc
16
CoumAc CoumAc CoumAc CoumAc
Scheme 1. Regio- and chemo-selective acylation of di-O-isopropylidene 4 with cinnamoyl chloride 5 and p-acetoxycinnfamoyl chloride 6.

P. Panda et al. / European Journal of Medicinal Chemistry 53 (2012) 1e12
3
Table 1
Table 2
Regio- and chemo-selective acylation of di-O-isopropylidene sucrose 4 with cin-
namoyl chloride 5.
Regio- and chemo-selective acylation of di-O-isopropylidene 4 with and p-acetox-
ycinnamoyl chloride 6.
Entry
1
Equiv. of acid
chloride 5
Time (d)
9
Product
Yield (%)
Total
yield (%)
Entry
1a
Equiv of acid
chloride 6
Temp.
rt
Time (d)
9
Product
Yield (%)
Total
yield (%)
1.1
7
8
9
40
16
31
12
17
21
36
56
1.1
12
13
14
12
14
12
14
14
14
15
16
14
15
16
15
16
15
16
30
10
6
20
4
ca 5
51
20
5
33
9
46
2
3
2.2
3.3
5
3
31
29
9
2a
3b
1.1
2.2
50 ꢁC
rt
14
1
24
56
10
10
11
4
4.4
2
57
4c
5
2.2
3.3
50 ꢁC
rt
14
9
20
47
compound 7 was obtained as the major product in 40% yield along
with compound 8 in 16% yield as white solids. Reaction of di-O-
isopropylidene 4 with 2.2 mol equiv of acid chloride 5 (entry 2,
Table 1) afforded compound 9 as the sole product (31% yield).
Attempts to increase the yield of compound 9 according to the
method reported by Duynstee et al. [12] where the reaction was
conducted at ꢀ30 ꢁC was not successful since majority of the
starting material was recovered unchanged. When di-O-iso-
propylidene 4 was treated with 3.3 mol equiv of cinnamoyl chloride
5, compound 10 was obtained as the major product in 17% yield
along with compound 9 in 12% yield (Table 1, entry 3). Further
increase in the amount of cinnamoyl chloride 5 to 4.4 mol equiv
gave compound 11 in 36% yield along with compound 10 in 21%
yield (Table 1, entry 4). The results above indicated that mono-
(7, 8), di- (9), tri- (10) and tetra- (11) acylated PSEs can be obtained
using appropriate number of equivalents of the acid chloride.
6
3.3
50 ꢁC
2
5
49
31
13
22
50
24
67
7
8
4.4
4.4
rt
4
2
72
91
50 ꢁC
a
40% of di-O-isopropylidene 4 was recovered.
20% of compound 4 was recovered.
no improvement in the yield of product 14 was observed from day 2 to day 14
b
c
(TLC and 1H NMR analysis).
to give a product distribution of di-acylated 14, tri-acylated 15 and
tetra-acylated 16 products; (ii) at any instance, tri-acylated 15
dominated the reaction products while di-acylated 14 and tetra-
acylated 16 were formed in much lower yields; (iii) After nine
days, tri-acylated product 15 was obtained in 33% yield while di-
acylated product 14 and tetra-acylated product 16 were obtained
in 5% and 9% yields, respectively (Table 2, entry 5); (iv) the products
distribution observed here is different to the one observed in Khan’s
[14] benzoylation where di-benzolylated product was a clear major
product (36% yield) while tri-benzoylated product was obtained in
9% yield. This indicates that the selectivity and reactivity of the OH
groups of di-O-isopropylidene 4 during the acylation with benzoyl
chloride and p-acetoxycinnamoyl chloride 6 are different. When the
same reaction was conducted at 50 ꢁC for 2 days (Table 2, entry 6),
again similar results were observed and di-acylated product 14 was
formed in 5% yield, tri-acylated products 15 in 31% yield while tetra-
acylated product 16 was obtained in 13% yield (Table 2, entry 6).
Di-O-isopropylidene 4 on treatment with 4.4 equiv of p-acetox-
ycinnamoyl chloride 6 for 4 days (Scheme 1) provided compound
16 in 50% yield, together with compound 15 (22% yield) (Table 2,
entry 7). When the same reaction was repeated at 50 ꢁC, the yield of
tetra-acylated product 16 improved to 67% while the yield of tri-
esterified product 15 remained at 24% (Table 2, entry 8). We can
conclude that the products distribution and yield depend upon the
acid chloride used and the reaction conditions (time, temperature).
Different acid chlorides give different product distributions, yields
and products while higher reaction temperature and longer times
reduce the product yield and lead to the formation of intractable
products that complicate the purification process.
2.1.2. Regio- and chemo-selective acylation of di-O-isopropylidene
4 with p-acetoxycinnamoyl chloride 6
Following the conditions developed for acylation of di-O-iso-
propylidene 4 with cinnamoyl chloride 5, we then focused our
attention on the regio- and chemo-selective acylation using
p-acetoxycinnamoyl chloride 6 [29] (Table 2, Scheme 1) in order to
find out the optimal reaction conditions for the synthesis of lapa-
thoside D 1. When di-O-isopropylidene 4 was reacted at rt with 1.1
equiv of acid chloride 6, compound 12 was obtained as the major
product in 30% yield along with compounds 13 (10% yield), 14
(6% yield) and the starting material di-O-isopropylidene 4 (40%)
(Table 2, entry 1). Attempts to drive the reaction to completion by
raising the reaction temperature to 50 ꢁC for extended time (up to
14 days) were not successful as compounds 12 and 14 were
obtained only in 20% and 4% yields, respectively (Table 2, entry 2)
along with the mixtures of intractable products. We observed that
at higher reaction temperature, various decomposition products
were obtained indicating the instability of the products at elevated
temperature. When di-O-isopropylidene 4 was treated with 2.2 mol
equiv of p-acetoxycinnamoyl chloride 6 at rt for 24 h (Table 2, entry
3), it afforded compound 14 as white solid in 51% yield along with
compound 12 (ca 5%) and unreacted di-O-isopropylidene 4 (20%).
Increasing the reaction temperature to 50 ꢁC and reaction time (up
to 14 days) has negative effect on the yield where compound 14 was
obtained only in 20% yield (Table 2, entry 4). Here, it is important to
note that as the reaction time increased, more intractable reaction
mixtures were formed providing low yield of product 14 and
making the purification very difficult. Subsequently, we attempted
to increase the yield of compound 14, the precursor for lapathoside
D 1, by reacting di-O-isopropylidene 4 with 3.3 equiv of p-acetox-
ycinnamoyl chloride 6 at rt. The reaction progress was followed by
1H NMR and crude samples were taken every 12 h for 9 days to
examine the distribution of the products and reactivity toward
p-acetoxycinnamoyl chloride 6. Analysis of the 1H NMR spectra
indicated that: (i) di-O-isopropylidene 4 was consumed within 12 h
2.1.3. Deprotection of the acetal groups: Preparation of compounds
17-20
We then turned our attention to the deprotection of the acetal
groups of precursors 9e11 and 14. Several acetal deprotection
conditions [12,16,30e34], have been reported with variable success
depending upon the nature of the starting material. After several
trials, deprotection using 60% aq. AcOH at 80 ꢁC gave the
best results (Scheme 2). Therefore, compounds 9e11 and 14
were subjected separately to acetal deprotection and the crude
products were recrystallized from EtOAc or purified by column

4
P. Panda et al. / European Journal of Medicinal Chemistry 53 (2012) 1e12
OH
OH
O
O
HO
R3O
R4'O
HO
O
OR6'
OR3'
17 : R3 = R4' = H; R3' = R6' = Cinn
18 : R3 = H; R3' = R4' = R6' = Cinn
19 : R3 = R3' = R4' = R6' = Cinn
O
R3O
R3'O
O
O
O
OR6'
20 : R3 = R4' = H; R3' = R6' = CoumAc
R4'O
O
O
O
9 : R3 = R4' = H; R3' = R6' = Cinn
10 : R3 = H; R3' = R4' = R6' = Cinn
11 : R3 = R3' = R4' = R6' = Cinn
O
R3O
R3'O
O
O
O
OR6'
14 : R3 = R4' = H; R3' = R6' = CoumAc
R4'O
O
O
O
21 : R3 = R4' = Ac; R3' = R6' = Cinn
22 : R3 = Ac; R3' = R4' = R6' = Cinn
Scheme 2. Preparation of compounds 17e22.
chromatography using a gradient of CH2Cl2-EtOAc as eluent to
afford compounds 17e20, respectively, as white solids in yields
ranging from 49% to 69% (Scheme 2).
95% ethanolic solution of piperidine or pyrrolidine to remove the
acetate protecting groups without affecting the cinnamate ester
functionality in the fully protected l-arabinofuranoside. Gladly,
when compound 20 was subjected to Helm et al. [29] deacetylation
conditions, lapathoside D 1 was obtained as white solid in 70% yield
(Scheme 3).
In comparison to the NMR spectra of compounds 9e11 and 14,
compounds 17e20 indicated the absence of the characteristic signals
for the two isopropylidene moieties usually observed in the 1H NMR
spectra at
spectra at
d
1.20e1.53 ppm (4 ꢂ s,12H, 2 (CH3)2C) and in the 13C NMR
19.0e29.1 ppm (4 x 2 (CH3)2C) and 99.6e101.8 ppm (2 ꢂ
The 1H (Fig. 2) and 13C NMR spectra of lapathoside D 1 indicated
the loss of the characteristic signals for the two acetyl moieties,
d
(CH3)2C). Compounds 17e20 also showed a characteristic downfield
represented by the proton signals at d
2.28 (s, 6H, H-1100) and
shift of the anomeric (H-1) protons from a typical value of
observed in the 9e11 and 14 to ca 5.0 ppm.
d
6.15 ppm
carbon signals at
d
21.0 (2 ꢂ C-1100) and 170.9 ppm (2 x C-1000). The
d
success of the deprotection was further confirmed in the IR spec-
trum of the lapathoside D 1 where peaks corresponding to the
acetyl ester carbonyl group at 1764 cmꢀ1 in compound 20 have
disappeared. Furthermore, the HReESIeMS spectrum of lapatho-
side D 1 showed m/z 657.1786 [M þ Na]þ (calcd 657.1790 for
C30H34O15Na). The structure of Lapathoside D 1 was further
confirmed by comparison to the data reported for the isolated
natural product (See supporting information) [8].
2.1.4. Acetylation of the free OH groups using excess Ac2O: synthesis
of compounds 21 and 22
Acetyl groups attached directly to the sucrose moiety were
reported to influence the biological activity of some PSEs [5,35].
Consequently, compounds 9 and 10 were acetylated with excess
Ac2O to give compounds 21 and 22, in 88% and 86% yield as white
solids, respectively (Scheme 2). The antitumor activities of
compounds 21 and 22 will be examined and compared with similar
structures (See Section 2.2).
It was of interest to deacetylate compound 15 to further study
the effect of the acetyl groups on the cytotoxicity. This was
accomplished in a similar fashion to the deacetylation of compound
20. Thus, compound 23 was obtained as white solid in 46% yield
(Scheme 4).
2.1.5. Deacetylation of the acetylated phenyl rings: Preparation of
lapathoside D 1 and compound 23
In order to complete the synthesis of lapathoside D 1, deacety-
lation of the phenyl rings of compound 20 is required. Several
deacetylation methods for sugar esters are known in literature
[17,28,29,36e38]. For example, Helm et al. [29] successfully used
2.2. Biological activities
Selected PSEs Lapathoside D 1, 9e11 and 14e23 were subjected
to in vitro cytotoxicity studies against human cervical epithelioid
OH
OH
OH
OH
O
O
HO
HO
HO
O
O
HO
Pyrrolidine
HO
HO
HO
HO
O
O
OCoumAc
OCoum
OCoum
95% EtOH, rt, 2 h
OCoumAc
Lapathoside D 1
20
O
O
Coum =
HO
CoumAc =
AcO
Scheme 3. Preparation of lapathoside D 1.

P. Panda et al. / European Journal of Medicinal Chemistry 53 (2012) 1e12
5
Fig. 2. 1H NMR spectrum of lapathoside D 1 (300 MHz, CD3OD).
carcinoma cells (HeLa) using MTS (3-(4,5-dimethylthiazol-2-yl)-5-
(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium)
assay method at 48 h exposure and the results compared with
camptothecin (CPT) as a positive control [5,39e42]. The IC50 values
of these compounds are shown in Table 3. Lapathoside D 1 (Table 3,
entry 1), its analog compounds 17 (Table 3, entry 8) and 20 (Table 4,
hope that these compounds would have better antitumor activities.
To our delight, compounds 21 (0.58 M) and 22 (0.05 M) showed
enhanced cytotoxicities in comparison to their corresponding
parent compounds 9 (0.97 M) and 10 (1.52 M). The above results
suggested that the acetyl and di-O-isopropylidene groups directly
attached to the sucrose core play a positive role in mediating the
cytotoxicities of PSEs.
m
m
m
m
entry 13) did not show any appreciable activity upto 100
concentration.
mM
From the results shown in Table 3, we can conclude:
At this point, it seemed that the substitution on phenyl ring did
not influence the antitumor activities. But the tri- 18 and tetra- 19
variant PSEs bearing cinnamoyl groups were found to have signif-
(i) In general, cinnamoyl PSEs showed better IC50 values
compared to coumaroyl and acetyl coumaroyl PSEs (Table 3).
(ii) The di-O-isopropylidene groups containing compounds
exhibited significant cytotoxicities thus underscoring the
positive effect of the di-O-isopropylidene groups in these
compounds (Table 3).
icant antitumor activity with the IC50 values of 4.10 and 0.47 mM,
respectively (Table 3, entries 9 &10). With these encouraging
results, it was of interest to find the antitumor activity of the cor-
responding di-O-isopropylidene compounds 9e11 and 14e16. It
was anticipated that the di-O-isopropylidene groups in compounds
9e11 and 14e16 would provide restricted conformation and may
have an influence on the antitumor activity. Indeed, di-O-iso-
(iii) Cinnamoyl di-O-isopropylidene sucrose esters: 11 (tetra-,
IC50 ¼ 0.25
IC50 ¼ 1.52 M).
(iv) Coumaryl di-O-isopropylidene sucrose esters: 16 (tetra-,
IC50 ¼ 0.56 M) > 14 (di-, IC50 ¼ 2.46 M) > 15 (tri-,
IC50 ¼ 5.26 M).
mM) > 9 (di, IC50 ¼ 0.97
mM) > 10 (tri-,
m
propylidene compounds 9 (0.97
14 (2.46 M) showed better IC50 values compared to their coun-
terparts 17 (>100 M), 18 (4.10 M), 19 (0.47 M) and 1 (>100 M),
mM), 10 (1.52 mM), 11 (0.25 mM) and
m
m
m
m
m
m
m
m
respectively. Similarly, tri- and tetra- variants 15 and 16 were
synthesized and found to have significant cytototoxicity with their
IC50 values 5.26 and 0.56 mM, respectively. These results underscore
the positive influence of the di-O-isopropylidene on the antitumor
activity. Kawai et al.23 and Kuo et al.5 independently suggested that
acetyl moieties on the sucrose core in PSEs might be responsible for
mediating the observed activities. These reports encouraged us to
synthesize compounds having acetyl groups attached to the
sucrose moiety. Thus compounds 20 and 21 were prepared in the
(v) The activity data for the compounds containing phenolic and
acetyl groups on the phenyl ring seems to vary with the
structure of the PSE. It appears that both phenolic and acetyl
groups on the phenyl ring don’t play a major role in mediating
the cytotoxic activities of the PSEs shown in Table 3.
(vi) Compound 21 bearing two acetyl groups on sucrose moiety
showed 2 times improved activity compared to its parent
compound 9 without acetyl groups. Similarly, compound 22
bearing one acetyl group on sucrose moiety showed 5 times
OR3'
O
R3O
OR3'
O
R3O
O
O
O
O
O
O
OR6'
Pyrrolidine
OR6'
R4'O
O
R4'O
O
O
O
95% EtOH, rt, 1 h
O
O
23 : R3 = H, R3' = R4' = R6' = Coum
15 : R3 = H, R3' = R4' = R6' = CoumAc
O
O
Coum =
HO
CoumAc =
AcO
Scheme 4. Preparation of compound 23.

6
P. Panda et al. / European Journal of Medicinal Chemistry 53 (2012) 1e12
Table 3
In Vitro cytotoxicity (IC50
(
mM)) of selected PSEs against human cervical epithelioid carcinoma (HeLa) cells at 48 h of exposure.
Entry
Comp
IC50
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
1
9
0.97
10
1.52
11
0.25
14
2.46
15
5.26
16
0.56
17
>100
18
4.10
19
0.47
20
>100
21
0.58
22
0.05
23
7.63
CPT
0.40
a
>100
a
IC50
(
mM): the concentration that induces 50% growth inhibition compared with untreated control cells and were calculated from three independent experiments.
Table 4
4.1.1. General procedure 1: Regioselective acylation of di-O-
isopropylidene 4 with cinnamoyl chloride 5 and p-
acetoxycinnamoyl chloride 6
IC50 values of selected synthesized PSEs 14,15 and 18 along with CPT at 24 h and 48 h
of exposure.
No
Compound
IC50
(mM)
Di-O-isopropylidene 4 (1.0 g, 2.4 mmol) was dissolved in dry
pyridine (ca 10 mL) by stirring under nitrogen atmosphere. The
resulting solution was then cooled to 0 ꢁC in an ice bath. Cinnamoyl
chloride 5 or p-acetoxycinnamoyl chloride 6 was added slowly at
24 H
48 H
1
2
3
4
14
15
18
CPT
19.44
12.22
7.64
2.46
5.26
4.10
0.40
0
ꢁC and the reaction was left to stir while warming to rt. Stirring
1.57
was continued until the reaction was complete (TLC, 3:1 EtOAc-
hexanes). The resulting mixture was poured into vigorously stir-
red ice-water (100 mL) and the white solid precipitated was filtered
using a Buchner funnel. The precipitate was redissolved in EtOAc
(25 mL) and washed once with 1N HCl (50 mL). The aqueous layer
was back extracted with EtOAc (2 ꢂ 50 mL) and combined with the
original organic layer. The organic solution was then successively
washed with 5% NaHCO3 (50 mL) and brine (25 mL) and then dried
over anhydrous MgSO4 before being filtered. The EtOAc filtrates
were concentrated and the gummy residue obtained was subjected
to column chromatography using a gradient of CH2Cl2-EtOAc as
eluent. The product(s) were collected as separate fractions.
improved activity compared to its parent compound 11 which
did not bear acetyl group. These results support the literature
precedents which indicated the positive influence of the acetyl
groups on sucrose moiety.
To examine if the cytotoxicity is time dependent, a few
compounds were selected for evaluation of cytotoxicity at two
different time intervals of drug exposure by MTS assay (Table 4).
In the MTS time course of study, the selected PSEs shown in
Table 4 exhibited time-dependent antitumor activities with the IC50
values as shown. In all cases, using compounds 14, 15 and 18, the
IC50 values improved as the time increased from 24 to 48 h expo-
sure especially with compound 14 (Table 4, entry 1).
4.1.1.1. 60-Mono-O-cinnamoyl-2,10:4,6-di-O-isopropylidene sucrose 7
and
30-mono-O-cinnamoyl-2,10:4,6-di-O-isopropylidene
sucrose
8. Following general procedure 1, reaction between di-O-iso-
propylidene 4 (0.5 g, 1.2 mmol) and cinnamoyl chloride 5 (0.2 g,
1.3 mmol) in dry pyridine (5 mL) for 9 days gave compounds 7
(0.25 g, 40% yield) and 8 (0.10 g, 16% yield) as white solids.
3. Conclusions
Analytical data for 7: Rf
¼
0.09 (3:1 EtOAc-hexanes); mp
126e129 ꢁC; FTeIR (KBr) nmax: 3445, 2994, 2939, 1712, 1638, 1451,
Regio- and chemo-selective acylation of the free hydroxyl
groups of di-O-isopropylidene sucrose 4 with acid chlorides 5 and 6
was achieved in moderate yields and their reactivities were found
to be in the order of 60-OH > 30-OH > 40-OH > 3-OH. The selectivity
is affected by the reaction temperature, time and the nature of the
acylating agent. To our knowledge this is the first successful report
for the total synthesis of lapathoside D 1 together with 16 unnatural
PSEs in simple and short synthetic routes from sucrose 3 as inex-
pensive starting material. The preliminary MTS screening results
indicated that 11 out of the 14 synthesized PSEs showed significant
antitumor activities against HeLa cells at 48 h drug exposure with
1384, 1312,1270, 1204, 1173,1135, 1069, 943, 859, 770, 716 cmꢀ1; 1H
NMR (300 MHz, CDCl3):
d
1.43, 1.45, 1.46, 1.51 (4 ꢂ s, 12H, (CH3)2C),
3.52 (d, 1H, J ¼ 12.6 Hz, H-10a), 3.60 (dd, 1H, J ¼ 9.3 Hz, 9.5 Hz, H-4),
3.70 (m, 1H, H-6a), 3.77 (dd, 1H, J ¼ 3.3 Hz, 8.7 Hz, H-2), 3.89e3.98
(m, 3H, H-30, H-5, H-6b), 4.10 (dd, 1H, J ¼ 9.3 Hz, 9 Hz, H-3), 4.21
(m, 2H, H-40, H-50), 4.28 (m,1H, H-10b), 4.34 (m,1H, H-60a), 4.54 (dd,
1H, J ¼ 4.2 Hz, 11.4 Hz, H-60b), 6.21 (d, 1H, J ¼ 3.3 Hz, H-1); trans-
cinnamoyl units: 6.46 (d, 1H, J ¼ 16.2 Hz, H-800), 7.27e7.37 (m, 3H,
H-300, H-400, H-500), 7.48e7.55 (m, 2H, H-200, H-600), 7.69 (d, 1H,
J ¼ 16.2 Hz, H-700); 13C NMR (75.48 MHz, CDCl3):
d 19.2, 24.2, 25.2,
29.0 (4 ꢂ (CH3)2C), 62.3 (C-6), 63.7 (C-5), 65.9 (C-60), 66.5 (C-10),
69.2 (C-3), 73.4 (C-4), 73.9 (C-2), 77.3 (C-40), 78.9 (C-30), 79.6 (C-50),
91.0 (C-1), 100.1, 102.3 (2 ꢂ (CH3)2C), 103.6 (C-20), trans-cinnamoyl
units: 117.6 (C-800), 128.2 (C-200, C-600), 128.9 (C-300, C-500), 130.4 (C-
400), 134.3 (C-100), 145.5 (C-700), 167.2 (C-900); ESI-Mass (positive
mode): m/z 575.20 [M þ Na] þ, calcd 575.22 for C27H36O12Na;
HReESIeMS (positive mode): found m/z 575.2092 [M þ Na]þ, calcd
575.2099 for C27H36O12Na. Analytical data for 8: Rf ¼ 0.24 (3:1
EtOAc-hexanes); FTeIR (KBr) nmax: 3468, 2993, 2927, 1718, 1636,
1576, 1507, 1496, 1452, 1384, 1331, 1269, 1205, 1171, 1093, 1069,
their IC50 values ranging from 0.05 to 7.63
mM compared with
standard anticancer drug CPT. Time-dependent antitumor activities
were also evaluated. The preliminary SAR correlation studies
revealed that the type, number and positionof the phenylpropanoid
units on the sucrose core influence the activity against HeLa cells.
We envision that the present approach will not only form a model
synthesis for such useful PSEs but also helps to provide sufficient
materials for carrying out proper mechanism of action and struc-
ture activity relationship studies. The MTS primary screening
results also indicated that PSEs might be potentially valuable source
for new potent anticancer drug candidates.
1012, 944, 860, 768 cmꢀ1 1H NMR (300 MHz, CDCl3):
; d 1.39, 1.45,
1.52, 1.53 (4 ꢂ s, 12H, (CH3)2C), 3.60 (m, 2H, H-10a, H-2), 3.70 (m, 2H,
H-6a, H-60a), 3.77 (m,1H, H-4), 3.85 (m, 2H, H-5, H-6b), 3.93 (m, 2H,
H-3, H-60b), 4.07 (d, 1H, J ¼ 12.3 Hz, H-10b), 4.13 (m, 1H, H-50),
4.84e4.95 (m, 1H, H-40), 5.03 (d, 1H, J ¼ 7.5 Hz, H-30), 6.21 (d, 1H,
J ¼ 3.6 Hz, H-1); trans-cinnamoyl units: 6.55 (d, 1H, J ¼ 16.2 Hz,
H-800), 7.39e7.45 (m, 3H, H-300, H-400, H-500), 7.60e7.63 (m, 2H, H-200,
H-600), 7.82 (d, 1H, J ¼ 16.2 Hz, H-700); 13C NMR (75.48 MHz, CDCl3):
4. Experimental section
4.1. Chemistry
For the synthesis of 2,10:4,6-di-O-isopropylidene sucrose 4 and
p-acetoxycinnamoyl chloride 6 see Supporting Information.

P. Panda et al. / European Journal of Medicinal Chemistry 53 (2012) 1e12
7
d
19.1, 24.2, 25.4, 29.0 (4 ꢂ (CH3)2C), 61.2 (C-6), 61.9 (C-5), 64.0
(C-300, C-500),130.6 (C-400),134.0 (C-100),146.4 (C-700),165.8 (C-900); R3:
117.6 (C-800), 128.4 (C-200, C-600), 128.8 (C-300, C-500), 130.7 (C-400),
134.3 (C-100), 147.0 (C-700), 166.3 (C-900); ESI-Mass (positive mode):
m/z 835.34 [M þ Na] þ, calcd 835.30 for C45H48O14Na; HReESIeMS
(positive mode): found m/z 835.2954 [M þ Na]þ, calcd 835.2936 for
C45H48O14Na; Anal. Calcd for C45H48O14: C, 66.49; H, 5.95; found: C,
67.12; H, 6.37.
(C-60), 66.5 (C-10), 70.1 (C-3); 71.7 (C-40); 72.7 (C-2), 73.5 (C-4), 80.4
(C-300), 84.3 (C-50), 91.0 (C-1), 100.0, 102.0 (2 ꢂ (CH3)2C), 103.5
(C-2 ); trans-cinnamoyl units: 116.6 (C-800), 128.5 (C-200, C-600), 129.0
(C-300, C-500), 130.9 (C-400), 133.9 (C-100), 147.1 (C-700), 167.6 (C-900);
ESI-Mass (positive mode): m/z 575.26 [M þ Na] þ, calcd 575.22 for
C27H36O12Na.
4.1.1.2. 30,60-Di-O-cinnamoyl-2,10:4,6-di-O-isopropylidene
sucrose
4.1.1.4. 3,30,40,60-Tetra-O-cinnamoyl-2,10:4,6-di-O-isopropylidene
sucrose 11. Following general procedure 1, reaction between the di-
O-isopropylidene 4 (0.5 g, 1.2 mmol) and cinnamoyl chloride 5
(0.9 g, 5.2 mmol) in dry pyridine (5 mL) for 2 days furnished
compounds 11 (0.40 g, 36% yield) and 10 (0.20 g, 21% yield) as white
solids. Analytical data for 11: Rf ¼ 0.92 (3:1 EtOAc-hexanes); mp
88e93 ꢁC; FTeIR (KBr) nmax: 2992, 2941, 1719, 1636, 1578, 1497,
1450, 1384, 1310, 1270, 1203, 1155, 1072, 1008, 944, 861, 767, 708,
9. Following general procedure 1, reaction between the di-O-iso-
propylidene 4 (2.2 g, 5.2 mmol) and cinnamoyl chloride 5 (1.9 g,
11.5 mmol) in dry pyridine (20 mL) for 5 days gave compound 9 [12]
(1.1 g, 31% yield) as white solid. Analytical data for 9: Rf ¼ 0.73 (3:1
EtOAc-hexanes); mp 118e120 ꢁC; FTeIR (KBr) nmax: 3479, 3418,
2992, 2941,1715,1637,1578,1497,1451,1384,1312,1270,1204, 1169,
1070, 1011, 944, 860, 768, 712, 684, 658 cmꢀ1
CDCl3):
;
1H NMR (300 MHz,
1.39, 1.42, 1.52, 1.53 (4 ꢂ s, 12H, (CH3)2C), 3.60 (m, 1H, H-
d
683 cmꢀ1; 1H NMR (300 MHz, CDCl3):
d
1.20, 1.28, 1.44, 1.47 (4 ꢂ s,
10a), 3.67 (m, 1H, H-4), 3.75 (m, 2H, H-2, H-6a), 3.83 (dd, 1H,
J ¼ 9.9 Hz, 4.5 Hz, H-5), 3.90 (m, 1H, H-3), 3.97 (dd, 1H, J ¼ 4.8 Hz,
9.9 Hz, H-6b), 4.08 (m, 1H, H-10b), 4.39 (m, 2H, H-50, H-60a), 4.50
(m, 2H, H-40, H-60b), 4.95 (d, 1H, J ¼ 6.3 Hz, H-30), 6.13 (d, 1H,
J ¼ 3.6 Hz, H-1); trans-cinnamoyl units: R1: 6.48 (d, 1H, J ¼ 16.2 Hz,
H-800), 7.37e7.43 (m, 3H, H-300, H-400, H-500), 7.51e7.54 (m, 2H, H-200,
H-600), 7.71 (d, 1H, J ¼ 16.2 Hz, H-700); R2: 6.54 (d, 1H, J ¼ 16.2 Hz,
H-800), 7.37e7.43 (m, 3H, H-300, H-400, H-500), 7.59e7.62 (m, 2H, H-200,
H-600), 7.82 (d, 1H, J ¼ 16.2 Hz, H-700); 13C NMR (75.48 MHz, CDCl3):
12H, (CH3)2C), 3.64 (d, 1H, J ¼ 12.3 Hz, H-10a); 3.68e3.78 (m, 2H,
H-4, H-6a), 3.92e4.00 (m, 2H, H-2, H-5), 4.05 (dd, 1H, J ¼ 5.1 Hz,
10.2 Hz, H-6b), 4.24 (d, 1H, J ¼ 12.6 Hz, H-10b), 4.53e4.61 (m, 3H,
H-50, H-60a, H-60b), 5.37e5.43 (m, 2H, H-3, H-40), 5.62 (dd, 1H,
J ¼ 3.3 Hz, 5.1 Hz, H-30), 6.20 (d, 1H, J ¼ 3.6 Hz, H-1); trans-cinna-
moyl units: R1: 6.43 (d, 1H, J ¼ 15.9 Hz, H-800), 7.35e7.40 (m, 3H,
H-300, H-400, H-500), 7.49e7.52 (m, 2H, H-200, H-600), 7.63e7.75 (d, 1H,
J ¼ 15.9 Hz, H-700); R2 : 6.45 (d, 1H, J ¼ 15.9 Hz, H-800), 7.35e7.40
(m, 3H, H-300, H-400, H-500), 7.49e7.52 (m, 2H, H-200, H-600),
7.63e7.75 (m, 1H, H-700); R3 : 6.46 (d, 1H, J ¼ 15.9 Hz, H-800),
7.35e7.40 (m, 3H, H-300, H-400, H-500), 7.49e7.52 (m, 2H, H-200, H-600),
7.63e7.75 (m, 1H, H-700); R4 : 6.63 (d, 1H, J ¼ 15.9 Hz, H-800),
7.35e7.40 (m, 3H, H-300, H-400, H-500), 7.63e7.75 (m, 2H, H-200, H-600),
d
19.1, 24.1, 25.5, 29.1 (4 ꢂ (CH3)2C), 62.1 (C-6), 63.8 (C-5), 65.7
(C-60), 65.9 (C-10), 70.3 (C-3), 72.9 (C-4), 73.8 (C-2), 76.6 (C-40), 81.2
(C-30), 81.4 (C-50), 90.9 (C-1), 99.9, 101.8 (2 ꢂ (CH3)2C), 104.5 (C-20),
trans-cinnamoyl units: R1: 116.5 (C-800), 128.2 (C-200, C-600), 128.9
(C-300, C-500),130.4 (C-400), 133.8 (C-100),145.4 (C-700),166.8 (C-900); R2:
117.6 (C-800),128.5 (C-200, C-600), 129.0 (C-300, C-500),131.0 (C-400),134.3
(C-100), 147.3 (C-700), 167.7 (C-900); ESI-Mass (positive mode): m/z
705.32 [M þ Na]þ, calcd 705.26 for C36H42O13Na; HReESIeMS
(positive mode): found m/z 705.2502 [M þ Na]þ, calcd 705.2518
for C36H42O13Na; Anal. Calcd for C36H42O13: C, 63.33; H, 6.20;
found: C, 62.51; H, 6.12.
7.96 (d, 1H, J ¼ 15.9 Hz, H-700); 13C NMR (75.48 MHz, CDCl3):
d 19.0,
23.9, 25.5, 28.8 (4 ꢂ (CH3)2C), 62.1 (C-6), 64.3 (C-5), 65.0 (C-60), 66.2
(C-10), 71.0 (C-3), 71.6 (C-4), 71.9 (C-2), 77.4 (C-40), 77.8 (C-30), 80.2
(C-50), 91.7 (C-1), 99.6, 101.5 (2 ꢂ (CH3)2C), 105.0 (C-20); trans-
cinnamoyl units: R1: 116.5 (C-800), 128.1 (C-200, C-600), 128.7 (C-300,
C-500), 130.2 (C-400), 134.0 (C-100), 144.7 (C-700), 165.8 (C-900); R2: 116.8
(C-800), 128.2 (C-200, C-600), 128.8 (C-300, C-500), 130.3 (C-400), 134.3
(C-100), 145.2 (C-700), 165.9 (C-900); R3: 117.7 (C-800), 128.3 (C-200, C-600),
128.9 (C-300, C-500), 130.5 (C-400), 134.4 (C-100), 146.4 (C-700), 166.2
(C-900); R4: 118.2 (C-800), 128.3 (C-200, C-600), 128.9 (C-300, C-500), 130.7
(C-400), 134.5 (C-100), 147.4 (C-700), 166.5 (C-900); ESI-Mass (positive
mode): m/z 965.36 [M þ Na] þ, calcd 965.35 for C54H54O15Na;
HReESIeMS (positive mode): found m/z 965.3326 [M þ Na]þ, calcd
965.3355 for C54H54O15Na; Anal. Calcd for C54H54O15: C, 68.78; H,
5.77; found: C, 68.80; H, 6.09.
4.1.1.3. 30,40,60-Tri-O-cinnamoyl-2,10:4,6-di-O-isopropylidene sucrose
10. Following general procedure 1, reaction between the di-O-
isopropylidene 4 (0.5 g, 1.2 mmol) and cinnamoyl chloride 5 (0.7 g,
3.9 mmol) in dry pyridine (5 mL) for 3 days afforded compounds 9
(0.10 g, 12% yield) and 10 (0.16 g, 17% yield) as white solids.
Analytical data for 10: Rf
¼
0.80 (3:1 EtOAc-hexanes); mp
116e120 ꢁC; FTeIR (KBr) nmax: 3475, 2992, 2943, 1723, 1635, 1539,
1507, 1330, 1312, 1255, 1204, 1158, 1093, 1066, 1010, 943, 860, 767,
710, 684, 668 cmꢀ1
;
1H NMR (300 MHz, CDCl3):
d
1.29, 1.38, 1.47,
4.1.1.5. 60-Mono-O-acetoxycinnamoyl-2,10:4,6-di-O-isopropylidene
sucrose 12 and 30-mono-O-acetoxycinnamoyl-2,10:4,6-di-O-iso-
propylidene sucrose 13. Following general procedure 1, the reaction
between di-O-isopropylidene 4 (1.0 g, 2.4 mmol) and p-acetox-
ycinnamoyl chloride 6 (0.6 g, 2.7 mmol) in dry pyridine (10 mL) for 9
days at rt afforded compounds 12 (0.44 g, 30% yield), 13 (0.15 g, 10%
yield) and 14 (0.11 g, 6% yield) as white solids. Analytical data for 12:
1.50 (4 ꢂ s, 12H, (CH3)2C), 3.58 (app t, 1H, J ¼ 9.3 Hz, H-4); 3.68
(m, 2H, H-6a, H-10a), 3.73 (dd,1H, J ¼ 3.3 Hz, 5.4 Hz, H-2), 3.80e3.86
(m, 2H, H-3, H-5), 4.02 (dd, 1H, J ¼ 5.1 Hz, 10.2 Hz, H-6b), 4.19
(d, 1H, J ¼ 12.3 Hz, H-10b), 4.54 (m, 2H, H-50, H-60a), 4.61 (m, 1H,
H-60b), 5.37 (d, 1H, J ¼ 5.4 Hz, H-40), 5.61 (dd, 1H, J ¼ 3.6 Hz, 4.8 Hz,
H-30), 6.14 (d, 1H, J ¼ 3.3 Hz, H-1); trans-cinnamoyl units: R1: 6.55
(d, 1H, J ¼ 16.2 Hz, H-800), 7.26e7.38 (m, 3H, H-300, H-400, H-500),
Rf ¼ 0.10 (3:1 EtOAc-hexanes); mp 127e129 ꢁC; FTeIR (KBr) nmax
:
7.47e7.49 (m, 2H, H-200, H-600), 7.82 (d, 1H, J ¼ 16.2 Hz, H-700); R2
:
2994, 2934,1702,1636,1558,1507,1374,1319,1206,1167,1134,1069,
6.45 (d, 1H, J ¼ 16.2 Hz, H-800), 7.26e7.38 (m, 3H, H-300, H-400, H-500),
1014, 942, 857, 836, 700, 649 cmꢀ1 1H NMR (300 MHz, CDCl3):
;
7.47e7.49 (m, 2H, H-200, H-600), 7.71 (d, 1H, J ¼ 16.2 Hz, H-700); R3
:
d
1.45, 1.52 (2s, 12H, (CH3)2C), 3.50 (m, 1H, H-10a), 3.61 (dd, 1H,
6.43 (d, 1H, J ¼ 16.2 Hz, H-800), 7.26e7.38 (m, 3H, H-300, H-400, H-500),
7.57e7.60 (m, 2H, H-200, H-600), 7.69 (d, 1H, J ¼ 16.2 Hz, H-700); 13C
J ¼ 9.3 Hz, 9.0 Hz, H-4), 3.73 (m, 2H, H-2, H-6a), 3.92 (m, 3H, H-30,
H-5, H-6b), 4.07 (m, 1H, H-3), 4.19 (m, 2H, H-40, H-50), 4.30 (m, 2H,
H-10b, H-60a), 4.52 (m, 1H, H-60b), 6.19 (d, 1H, J ¼ 3.0 Hz, H-1); trans-
NMR (75.48 MHz, CDCl3):
d
19.0, 24.0, 25.4, 28.8 (4 ꢂ (CH3)2C), 62.0
(C-6), 63.8 (C-5), 64.8 (C-60), 66.2 (C-10), 70.1 (C-3), 72.8 (C-4), 73.8
(C-2), 77.3 (C-40), 77.7 (C-30), 80.1 (C-50), 91.3 (C-1), 99.6, 101.7
(2 ꢂ (CH3)2C), 104.8 (C-20); trans-cinnamoyl units: R1: 116.4 (C-800),
128.0 (C-200, C-600), 128.8 (C-300, C-500), 130.2 (C-400), 133.9 (C-100),
145.1 (C-700), 165.7 (C-900); R2: 116.6 (C-800), 128.2 (C-200, C-600), 128.8
p-coumaroyl units:
d
2.31 (1s, 3H, H-1100), 6.41 (d, 1H, J ¼ 15.9 Hz,
H-800), 7.11 (d, 2H, J ¼ 8.7 Hz, H-300, H-500), 7.52 (d, 2H, J ¼ 8.4 Hz, H-200,
H-600), 7.66 (d, 1H, J ¼ 15.9 Hz, H-700); 13C NMR (75.48 MHz, CDCl3):
d
19.2, 24.3, 25.3, 29.1 (4 ꢂ (CH3)2C), 62.3 (C-6), 63.8 (C-5), 65.9 (C-60),
66.5 (C-10), 69.4 (C-3), 73.4 (C-4), 73.9 (C-2), 77.5 (C-40), 79.0 (C-30),

8
P. Panda et al. / European Journal of Medicinal Chemistry 53 (2012) 1e12
79.6 (C-50), 91.0 (C-1),100.1,102.3 (2 ꢂ (CH3)2C),103.6 (C-20); trans-p-
coumaroyl units: 21.1 (C-1100), 117.8 (C-800), 122.2 (C-300, C-500), 129.4
(C-200, C-600), 132.0 (C-100), 144.4 (C-700), 152.2 (C-400), 167.1 (C-900þ),
169.2 (C-1000); ESI-Mass (positive mode): m/z 633.26 [M þ Na] ,
calcd 633.23 for C29H38O14Na; HReESIeMS (positive mode): found
m/z 633.2144 [M þ Na]þ, calcd 633.2154 for C29H38O14Na; Anal.
Calcd for C29H38O14: C, 57.04; H, 6.27; found: C, 54.78; H, 6.07.
(3:1 EtOAc-hexanes); mp 135e138 ꢁC; FTeIR (KBr) nmax: 2993,
2942,1768,1718, 1636, 1602 1559, 1507, 1419,1372,1322,1205,1165,
1065, 1012, 945, 912, 858, 837, 726, 653 cmꢀ1
;
1H NMR
(300 MHz,CDCl3):
d
1.29, 1.37, 1.47, 1.49 (4 ꢂ s, 12H, (CH3)2C), 3.56
(m, 2H, H-10a, H-4), 3.62 (m, 1H, H-6a), 3.77 (m, 1H, H-2), 3.85
(m, 2H, H-3, H-5), 4.00 (dd,1H, J ¼ 4.8 Hz,10.2 Hz, H-6b), 4.17 (d,1H,
J ¼ 12.6 Hz, H-10b), 4.50 (m, 2H, H-50, H-60a), 4.60 (m, 1H, H-60b),
5.33 (d, 1H, J ¼ 5.1 Hz, H-40), 5.57 (m, 1H, H-30), 6.11 (d, 1H,
J ¼ 3.3 Hz, H-1); trans-p-coumaroyl units: R1: 2.29 (s, 3H, H-1100),
6.38 (d, 1H, J ¼ 15.9 Hz, H-800), 7.06e7.14 (m, 2H, H-300, H-500),
7.48e7.51 (m, 2H, H-200, H-600), 7.60e7.69 (m, 1H, H-700), R2: 2.29
(s, 3H, H-1100), 6.39 (d,1H, J ¼ 15.9 Hz, H-800), 7.06e7.14 (m, 2H, H-300,
H-500), 7.48e7.51 (m, 2H, H-200, H-600), 7.60e7.69 (m, 1H, H-700), R3:
2.29 (s, 3H, H-1100), 6.49 (d, 1H, J ¼ 15.9 Hz, H-800), 7.06e7.14 (m, 2H,
H-300, H-500), 7.60e7.69 (m, 2H, H-200, H-600), 7.78 (d, 1H, J ¼ 15.9 Hz,
Analytical data for 13: Rf
¼
0.16 (3:1 EtOAc-hexanes); mp
120e124 ꢁC; FTeIR (KBr) nmax: 3485, 2994, 2925, 1768, 1718, 1636,
1602, 1508, 1419, 1373, 1322, 1269, 1206, 1167, 1091, 1069, 1016, 946,
856, 754, 729, 655; 1H NMR (300 MHz, CDCl3):
d 1.39, 1.45, 1.52, 1.53
(4 ꢂ s, 12H, (CH3)2C), 3.54 (m, 1H, H-10a), 3.64 (m, 1H, H-4), 3.68 (m,
2H, H-6a, H-60a), 3.77 (dd,1H, J ¼ 3.6 Hz, 9.0 Hz, H-2), 3.90 (m, 4H, H-
3, H-5, H-6b, H-60b), 4.07 (m, 1H, H-10b), 4.13 (m, 1H, H-50), 4.86 (dd,
1H, J ¼ 7.5 Hz, 7.2 Hz, H-40), 5.04 (d, 1H, J ¼ 7.8 Hz, H-30), 6.21 (d, 1H,
J ¼ 3.6 Hz, H-1); trans-p-coumaroyl units:
d
2.32 (1s, 3H, H-1100), 6.51
H-700); 13C NMR (75.48 MHz, CDCl3):
d 19.1, 24.1, 25.5, 29.0
(d, 1H, J ¼ 15.9 Hz, H-800), 7.16 (d, 2H, J ¼ 8.7 Hz, H-300, H-500), 7.63 (d,
(4 ꢂ (CH3)2C), 62.0 (C-6), 63.9 (C-5), 64.9 (C-60), 66.3 (C-10), 70.2
(C-3), 72.9 (C-4), 73.8 (C-2), 77.4 (C-40), 77.8 (C-30), 80.1 (C-50), 91.4
(C-1), 99.7, 101.8 (2 ꢂ (CH3)2C), 104.8 (C-20); trans-p-coumaroyl
units: R1: 21.1 (C-1100), 116.6 (C-800), 122.1 (C-300,C-500), 129.3 (C-200,
C-600), 131.6 (C-100), 144.1 (C-700), 152.1 (C-400), 165.7 (C-900), 169.0
(C-1000), R2: 21.1 (C-1100), 116.8 (C-800), 122.1 (C-300, C-500), 129.4 (C-200,
C-600), 131.7 (C-100), 145.4 (C-700), 152.4 (C-400), 165.8 (C-900), 169.0
(C-1000), R3: 21.1 (C-1100), 117.8 (C-800), 122.2 (C-300, C-500), 129.7 (C-200,
C-600), 132.1 (C-100), 145.9 (C-700), 152.5 (C-400), 166.3 (C-900þ), 169.1
(C-1000); ESI-Mass (positive mode): m/z 1009.31 [M þ Na] , calcd
1009.32 for C51H54O20Na; HReESIeMS (positive mode): found m/z
1009.3087 [M þ Na]þ, calcd 1009.3101 for C51H54O20Na; Anal. Calcd
for C51H54O20: C, 62.06; H, 5.51; found: C, 61.68; H, 5.91.
2H, J ¼ 8.4 Hz, H-200, H-600), 7.79 (d, 1H, J ¼ 15.9 Hz, H-700); 13C NMR
(75.48 MHz, CDCl3):
d
19.1, 24.2, 25.4, 29.0 (4 ꢂ (CH3)2C), 61.2 (C-6),
61.9 (C-60), 64.0 (C-5), 66.5 (C-10), 70.1 (C-3), 71.6 (C-40), 72.7 (C-4),
73.5 (C-2), 80.45 (C-30), 84.3 (C-50), 90.8 (C-1), 99.9, 102.0
(2 ꢂ (CH3)2C), 103.1 (C-20), trans-p-coumaroyl units:
d
21.2 (C-1100),
116.8 (C-800), 122.3 (C-300, C-500), 129.7 (C-200, C-600), 131.6 (C-100), 145.9
(C-700), 152.6 (C-400), 167.4 (C-900), 169.1 (C-1000); ESI-Mass (positive
mode): m/z 633.18 [M þ Na]þ, calcd 633.23 for C29H38O14Na;
HReESIeMS (positive mode): found m/z 633.2151 [M þ Na]þ, calcd
633.2154 for C29H38O14Na.
4.1.1.6. 30,60-Di-O-acetoxycinnamoyl-2,10:4,6-di-O-isopropylidene
sucrose 14. Following general procedure 1, the reaction between
di-O-isopropylidene 4 (1.0 g, 2.4 mmol) and p-acetoxycinnamoyl
chloride 6 (1.2 g, 5.2 mmol) in dry pyridine (10 mL) for 1 day at rt
gave compounds 14 (0.96 g, 51% yield) and 12 (0.07 g, 5% yield) as
white solids. Analytical data for 14: Rf ¼ 0.62 (3:1 EtOAc-hexanes);
mp 109e111 ꢁC; FTeIR (KBr) nmax: 3486, 2993, 2942, 1768, 1715,
1637, 1602, 1508, 1418, 1372, 1322, 1270, 1166, 1068, 1013, 945, 912,
4.1.1.8. 3,30,40,60-Tetra-O-acetoxycinnamoyl-2,10:4,6-di-O-iso-
propylidene sucrose 16. Following general procedure 1, the reaction
between di-O-isopropylidene 4 (1.0 g, 2.4 mmol) and p-acetox-
ycinnamoyl chloride 6 (2.4 g, 10.7 mmol) in dry pyridine (10 mL) for
4 days at rt furnished compounds 16 (1.40 g, 50% yield) and 15
(0.51 g, 22% yield) as white solids. Analytical data for 16: Rf ¼ 0.89
(3:1 EtOAc-hexanes); mp 138e140 ꢁC; FTeIR (KBr) nmax: 2992,
2943, 1764, 1718, 1635, 1601, 1559, 1507, 1419, 1374, 1319, 1204, 1165,
858, 837, 792, 724, 652 cmꢀ1; 1H NMR (300 MHz, CDCl3):
d 1.39,1.43,
1.49, 1.52 (4 ꢂ s, 12H, (CH3)2C), 3.67 (m, 2H, H-10a, H-4), 3.74 (m, 2H,
H-2, H-6a), 3.84 (m, 2H, H-3, H-5), 3.96 (m, 1H, H-6b), 4.07 (m, 1H,
H-10b), 4.38 (m, 2H, H-50, H-60a), 4.45 (m, 1H, H-40), 4.52 (m, 1H,
H-60b), 4.91 (d,1H, J ¼ 6.3 Hz, H-30), 6.13 (d,1H, J ¼ 3.3 Hz, H-1); trans-
p-coumaroyl units: R1: 2.32 (s, 3H, H-1100), 6.43 (d, 1H, J ¼ 15.9 Hz,
H-800), 7.12 (d, 2H, J ¼ 8.7 Hz, H-300, H-500), 7.54 (d, 2H, J ¼ 8.4 Hz, H-200,
H-600), 7.73 (d, 1H, J ¼ 15.9 Hz, H-700), R2: 2.32 (s, 3H, H-1100), 6.49 (d,
1H, J ¼ 15.9 Hz, H-800), 7.17 (d, 2H, J ¼ 8.7 Hz, H-300, H-500), 7.62e7.66
(m, 2H, H-200, H-600), 7.79 (d, 1H, J ¼ 16.2 Hz, H-700); 13C NMR
1047, 1011, 946, 911, 860, 836, 669, 650 cmꢀ1
;
1H NMR (300 MHz,
CDCl3):
d
1.19, 1.27, 1.43, 1.47 (4 ꢂ s, 12H, (CH3)2C), 3.65 (m, 2H,
H-10a, H-6a), 3.74 (d, 1H, J ¼ 9.9 Hz, H-4), 3.89e3.97 (m, 2H, H-2,
H-5), 4.00e4.06 (m, 1H, H-6b), 4.24 (d, 1H, J ¼ 12.3 Hz, H-10b),
4.48e4.59 (m, 3H, H-50, H-60a, H-60b), 5.33e5.40 (m, 2H, H-3, H-40),
5.59 (br dd, 1H, J ¼ 3.0 Hz, 5.4 Hz, H-30), 6.18 (d, 1H, J ¼ 3.6 Hz, H-1);
trans-p-coumaroyl units: R1: 2.31 (s, 3H, H-1100), 6.38 (d, 1H,
J ¼ 15.9 Hz, H-800), 7.04e7.14 (m, 2H, H-300, H-500), 7.45e7.55 (m, 2H,
H-200, H-600), 7.60e7.75 (m, 1H, H-700), R2: 2.31 (s, 3H, H-1100), 6.40
(d, 1H, J ¼ 15.9 Hz, H-800), 7.04e7.14 (m, 2H, H-300, H-500), 7.45e7.55
(m, 2H, H-200, H-600), 7.60e7.75 (m, 1H, H-700), R3: 2.31 (s, 3H, H-1100),
6.41 (d, 1H, J ¼ 15.9 Hz, H-800), 7.04e7.14 (m, 2H, H-300, H-500),
7.45e7.55 (m, 2H, H-200, H-600), 7.60e7.75 (m, 1H, H-700), R4: 2.31
(s, 3H, H-1100), 6.58 (d,1H, J ¼ 15.9 Hz, H-800), 7.04e7.14 (m, 2H, H-300,
H-500), 7.60e7.75 (m, 2H, H-200, H-600), 7.93 (d, 1H, J ¼ 15.9 Hz, H-700);
(75.48 MHz, CDCl3):
d
19.1, 24.1, 25.4, 29.1 (4 ꢂ (CH3)2C), 62.1 (C-6),
63.8 (C-5), 65.8 (C-60), 66.0 (C-10), 70.3 (C-3), 73.0 (C-4), 73.8 (C-2),
76.3 (C-40), 80.8 (C-30), 81.3 (C-50), 91.0 (C-1), 99.8, 101.7 (2 ꢂ
(CH3)2C), 104.4 (C-20); trans-p-coumaroyl units: R1: 21.1 (C-1100),
116.7 (C-800),122.1 (C-300, C-500),129.3 (C-200, C-600),131.6 (C-100),144.2,
145.9 (C-700),152.1 (C-400),166.7 (C-900),169.0 (C-1000); R2: 21.1 (C-1100),
117.8 (C-800), 122.2 (C-300, C-500), 129.7 (C-200, C-600), 132.0 (C-100),145.9
(C-700), 152.6 (C-400), 167.2 (C-900), 169.1 (C-1000); ESI-Mass (positive
mode): m/z 821.31 [M þ Na]þ, calcd 821.27 for C40H46O17Na.
HReESIeMS (positive mode): found m/z 821.2618 [M þ Na]þ, calcd
821.2627 for C40H46O17Na. Anal. Calcd for C40H46O17: C, 60.14; H,
5.80; found: C, 59.24; H, 6.04.
13C NMR (75.48 MHz, CDCl3):
d
19.0, 23.9, 25.5, 28.8 (4 ꢂ (CH3)2C),
62.1 (C-6), 64.3 (C-5), 65.0 (C-60), 66.2 (C-10), 70.9 (C-3), 71.5 (C-4),
71.9 (C-2), 77.5 (C-40), 77.8 (C-30), 80.2 (C-50), 91.7 (C-1), 99.6, 101.5
(2 ꢂ (CH3)2C), 105.0 (C-20), trans-p-coumaroyl units: R1: 21.1
(C-1100), 116.6 (C-800), 122.0 (C-300, C-500), 129.2 (C-200, C-600), 131.7
(C-100), 143.6 (C-700), 152.0 (C-400), 165.7 (C-900), 169.0 (C-1000), R2:
21.1 (C-1100), 116.9 (C-800), 122.1 (C-300, C-500), 129.3 (C-200, C-600), 132.0
(C-100), 144.0 (C-700), 152.1 (C-400), 165.7 (C-900), 169.1 (C-1000), R3:
21.1 (C-1100), 117.8 (C-800), 122.1 (C-300, C-500), 129.4 (C-200, C-600), 132.1
(C-100), 145.3 (C-700), 152.3 (C-400), 166.0 (C-900), 169.1 (C-1000), R4:
21.1 (C-1100), 118.3 (C-800), 122.2 (C-300, C-500), 130.0 (C-200, C-600), 132.2
(C-100), 146.2 (C-700), 152.4 (C-400), 166.3 (C-900), 169.2 (C-1000);
4.1.1.7. 30,40,60-Tri-O-acetoxycinnamoyl-2,10:4,6-di-O-isopropylidene
sucrose 15. Following general procedure 1, the reaction between
di-O-isopropylidene 4 (1.0 g, 2.5 mmol) and p-acetoxycinnamoyl
chloride 6 (1.9 g, 8.2 mmol) in dry pyridine (10 mL) for 9 days at rt
afforded compounds 15 (0.80 g, 33% yield), 14 (0.10 g, 5% yield) and
16 (0.25 g, 9% yield) as white solids. Analytical data for 15: Rf ¼ 0.67

P. Panda et al. / European Journal of Medicinal Chemistry 53 (2012) 1e12
9
ESI-Mass (positive mode): m/z 1197.36 [M þ Na]þ, calcd 1197.37 for
C62H62O23Na; HReESIeMS (positive mode): found m/z 1197.3598
[M þ Na]þ, calcd 1197.3574 for C62H62O23Na; Anal. Calcd for
C62H62O23: C, 63.37; H, 5.32; found: C, 63.29; H, 5.60.
(C-700), 165.8 (C-900), R2: 116.6 (C-800), 128.4 (C-300, C-500), 128.9 (C-200,
C-600), 130.7 (C-400), 134.1 (C-100), 146.7 (C-700), 166.1 (C-900), R3: 117.2
(C-800), 128.6 (C-300, C-500), 128.9 (C-200, C-600), 130.7 (C-400), 134.2
(C-100), 147.1 (C-700), 166.8 (C-900); ESI-Mass (positive mode): m/z
755.23 [M þ Na]þ, calcd 755.24 for C39H40O14Na; HR-ESI-MS (posi-
tive mode): found m/z 755.2310 [M þ Na]þ, calcd 755.2310 for
C39H40O14Na.
4.1.2. General procedure 3: Cleavage of the isopropylidene groups of
compounds 9-11 and 14
A solution of the diacetonide compound (1 mmol) in 60% aq.
AcOH (64 mL) was heated at 80 ꢁC until the reaction was completed
(TLC, 3:1 EtOAc-hexanes). The reaction mixture was then evapo-
rated to dryness under reduced pressure by co-distillation with
toluene (3 ꢂ 100 mL). The product was obtained as a white solid by
recrystallization in EtOAc (in case of 9 and 14) or purified by column
chromatography using a gradient of CH2Cl2-EtOAc as eluent (in case
of 10 and 11). The general procedure was used to prepare
compounds 17-20.
4.1.2.3. 3,30,40,60-Tetra-O-cinnamoylsucrose 19. Following general
procedure 3, a solution of compound 11 (0.5 g, 0.5 mmol) was
stirred with 60% aq. AcOH (32 mL) at 80 ꢁC for 20 min. The reaction
afforded compound 19 (0.25 g, 54% yield) as white solid. Analytical
data for 19:Rf ¼ 0.72 (3:1 EtOAc-hexanes); mp 91e94 ꢁC; FTeIR
(KBr) nmax cmꢀ1: 3061, 3028, 2992, 1716, 1636, 1578, 1497, 1450,
1384,1313,1270,1255,1204, 1170,1002, 943, 861, 708, 683; 1H NMR
(300 MHz, CD3OD):
d
3.64e3.68 (m, 1H, H-4), 3.84 (m, 4H, H-10b,
H-10a, H-2, H-6a), 4.06 (m, 2H, H-6b, H-5), 4.49e4.59 (m, 2H, H-50,
H-60a), 4.69 (dd, 1H, J ¼ 7.2 Hz, 11.1 Hz, H-60b), 5.16 (app t, 1H,
J ¼ 9.6 Hz, H-3), 5.54e5.61 (m, 2H, H-1, H-30), 5.77 (app t, 1H,
J ¼ 5.1 Hz, H- 40); trans-cinnamoyl units: R1: 6.44 (d, 1H,
J ¼ 15.9 Hz, H-800), 7.35e7.38 (m, 3H, H-300, H-400, H-500), 7.45e7.51
(m, 2H, H-200, H-600), 7.72 (d, 1H, J ¼ 15.9 Hz, H-700), R2: 6.45
(d, 1H, J ¼ 15.9 Hz, H-800), 7.35e7.38 (m, 3H, H-300, H-400, H-500),
7.45e7.51 (m, 2H, H-200, H-600), 7.73 (d, 1H, J ¼ 15.9 Hz, H-700), R3:
6.47 (d, 1H, J ¼ 16.2 Hz, H-800), 7.35e7.38 (m, 3H, H-300, H-400, H-500),
7.45e7.51 (m, 2H, H-200, H-600), 7.74 (d, 1H, J ¼ 16.2 Hz, H-700), R4:
6.62 (d, 1H, J ¼ 15.9 Hz, H-800), 7.35e7.38 (m, 3H, H-300, H-400, H-500),
7.60e7.64 (m, 2H, H-200, H-600), 7.89 (d, 1H, J ¼ 15.9 Hz, H-700); 13C
4.1.2.1. 30,60-Di-O-cinnamoylsucrose 17. Following general proce-
dure 3, a solution of compound 9 (0.4 g, 0.6 mmol) was stirred with
60% aq. AcOH (26 mL) at 80 ꢁC for 20 min. The reaction afforded
compound 17 (0.2 g, 54% yield) as white solid. Analytical data for 17:
Rf ¼ 0.06 (3:1 EtOAc-hexanes); mp 159e161 ꢁC; FTeIR (KBr) nmax
:
3453, 2925, 1712, 1693, 1640, 1496, 1451, 1353, 1313, 1283, 1206,
1156, 1066, 1032, 997, 924, 865, 766, 709, 681 cmꢀ1
;
1H NMR
(300 MHz, CD3OD): 3.41 (m, 1H, H-4), 3.45 (m, 1H, H-2), 3.62
d
(m, 2H, H-10b, H-10a), 3.70 (m, 1H, H-3), 3.81 (dd, 1H, J ¼ 4.8 Hz,
12 Hz, H-6a), 3.91e3.95 (m, 2H, H-6b, H-5), 4.17e4.23 (m, 1H, H-50),
4.47 (app t, 1H, J ¼ 8.1 Hz, H-40), 4.57 (m, 2H, H-60a, H-60b), 5.45
(d, 1H, J ¼ 3.6 Hz, H-1), 5.53 (d, 1H, J ¼ 7.8 Hz, H-30); trans-cinna-
moyl units: R1: 6.57 (d, 1H, J ¼ 15.9 Hz, H-800), 7.40e7.42 (m, 3H, H-
300, H-400, H-500), 7.60e7.67 (m, 2H, H-200, H-600), 7.74 (d, 1H,
J ¼ 15.9 Hz, H-700); R2: 6.62 (d, 1H, J ¼ 15.9 Hz, H-800), 7.40e7.42
(m, 3H, H-300, H-400, H-500), 7.60e7.67 (m, 2H, H-200, H-600), 7.80 (d,
NMR (75.48 MHz, CD3OD): d
62.4 (C-6), 64.3 (C-60), 64.6 (C-10), 69.6
(C-4), 70.6 (C-2), 73.6 (C-5), 76.4 (C-40), 77.1 (C-3), 78.0 (C-30),
79.6 (C-50), 92.5 (C-1), 105.5 (C-20); trans-cinnamoyl units: R1: 116.2
(C-800), 128.3 (C-300, C-500), 128.7 (C-200, C-600), 130.6 (C-400), 133.9
(C-100), 146.1 (C-700), 165.9 (C-900), R2: 116.4 (C-800), 128.3 (C-300, C-500),
128.9 (C-200, C-600), 130.6 (C-400), 134.0 (C-100), 146.3 (C-700), 166.9
(C-900), R3: 117.1 (C-800), 128.4 (C-300, C-500), 128.9 (C-200, C-600), 130.8
(C-400), 134.1 (C-100), 146.9 (C-700), 167.0 (C-900), R4: 117.2 (C-800),
128.4 (C-300, C-500), 129.0 (C-200, C-600), 130.8 (C-400), 134.1 (C-100),
148.0 (C-700), 168.6 (C-900); ESI-Mass (positive mode): m/z 885.27
[M þ Na]þ, calcd 885.28 for C48H46O15Na; HReESIeMS (positive
mode): found m/z 885.2725 [M þ Na]þ, calcd 885.2729 for
C48H46O15Na.
1H, J ¼ 15.9 Hz, H-700); 13C NMR (75.48 MHz, CD3OD):
d 62.7 (C-6),
65.1 (C-10), 66.6 (C-60), 71.5 (C-4), 73.2 (C-2), 74.5 (C-5), 75.0 (C-40,
C-3), 79.5 (C-30), 81.2 (C-50), 93.2 (C-1), 105.1 (C-20), trans-cinna-
moyl units: R1: 118.5 (C-800), 129.4 (C-300, C-500), 130.1 (C-200, C-600),
131.7 (C-400), 135.7 (C-100), 146.8 (C-700), 167.8 (C-900); R2: 118.6 (C-800),
129.6 (C-300, C-500), 130.1 (C-200, C-600), 131.7 (C-400), 135.8 (C-100), 147.3
(C-700), 168.5 (C-900); ESI-Mass (positive mode): m/z 625.23
[M þ Na]þ, calcd 625.20 for C30H34O13Na; HReESIeMS (positive
mode): found m/z 625.1879 [M þ Na]þ, calcd 625.1892 for
C30H34O13Na; Anal. Calcd for C30H34O13: C, 59.80; H, 5.69; found: C,
59.73; H, 5.82.
4.1.2.4. 30,60-Di-O-acetoxycinnamoylsucrose 20. Following general
procedure 3, a solution of compound 14 (1.6 g, 2.2 mmol) was
stirred in 60% aq. AcOH (103 mL) at 80 ꢁC for 20 min. The reaction
mixture afforded compound 20 (0.70 g, 49% yield) as a white solid.
4.1.2.2. 30,40,60-Tri-O-cinnamoylsucrose
18. Following
general
procedure 3, a solution of compound 10 (0.3 g, 0.4 mmol) was stirred
with 60% aq. AcOH (21 mL) at 80 ꢁC for 20 min. The reaction afforded
compound 18 (0.2 g, 69% yield) as white solid. Analytical data for 18:
Rf ¼ 0.11 (3:1 EtOAc-hexanes); mp 127e129 ꢁC; FTeIR (KBr) nmax
cmꢀ1: 3061, 3028, 2927, 1716, 1636, 1578, 1497, 1450, 1313, 1283,
1255, 1204, 1170, 1002, 864, 710, 683; 1H NMR (300 MHz, CD3OD):
Analytical data for 20: Rf
¼
0.61 (15:1 EtOAc-MeOH); mp
108e110 ꢁC; FTeIR (KBr) nmax: 3326, 2969, 2930, 1764, 1699, 1635,
1601, 1558, 1539, 1507, 1419, 1371, 1323, 1208, 1166, 1062, 995, 917,
862, 833, 700, 650 cmꢀ1; 1H NMR (300 MHz, CD3OD):
d 3.39e3.48
(m, 2H, H-2, H-4), 3.66 (m, 3H, H-10a, H-10b, H-3), 3.80 (m, 1H,
H-6a), 3.95 (m, 2H, H-6b, H-5), 4.16e4.24 (m,1H, H-50), 4.47 (dd,1H,
J ¼ 8.1 Hz, 8.4 Hz, H-40), 4.58 (m, 2H, H-60b, H-60a), 5.45 (br s, 1H,
H-1), 5.53 (d, 1H, J ¼ 7.8 Hz, H-30); trans-p-coumaroyl units: R1: 2.28
(s, 3H, H-1100), 6.55 (d,1H, J ¼ 15.9 Hz, H-800), 7.16 (m, 2H, H-300, H-500),
7.63e7.73 (m, 2H, H-200, H-600), 7.79 (d,1H, J ¼ 15.9 Hz, H-700), R2: 2.28
(s, 3H, H-1100), 6.60 (d,1H, J ¼ 15.9 Hz, H-800), 7.16 (m, 2H, H-300, H-500),
7.63e7.73 (m, 2H, H-200, H-600), 7.79 (d, 1H, J ¼ 15.9 Hz, H-700);
d
3.52 (m, 2H, H-10a, H-4), 3.61 (m, 2H, H-2, H-6a), 3.72 (m, 2H, H-10b,
H-3), 3.84 (m, 2H, H-6b, H-5), 4.27 (m, 2H, H-50, H-60a), 4.44 (m, 1H,
H-60b), 5.40 (br s, 1H, H-1), 5.55 (br s, 2H, H-30, H-40); trans-cinna-
moyl units: 6.22e6.40 (m, 1H, H-800), 7.17e7.30 (m, 3H, H-300, H-400,
H-500), 7.32e7.39 (m, 2H, H-200, H-600), 7.56e7.65 (m, 1H, H-700), R2:
6.22e6.40 (m, 1H, H-800), 7.17e7.30 (m, 3H, H-300, H-400, H-500),
7.32e7.39 (m, 2H, H-200, H-600), 7.56e7.65 (m, 1H, H-700), R3:
6.22e6.40 (m, 1H, H-800), 7.17e7.30 (m, 3H, H-300, H-400, H-500),
7.32e7.39 (m, 2H, H-200, H-600), 7.56e7.65 (m, 1H, H-700); 13C NMR
13C NMR (75.48 MHz, CD3OD):
d
62.7 (C-6), 65.2 (C-10), 66.6 (C-60),
71.5 (C-4), 73.2 (C-2), 74.6 (C-5), 75.1 (C-40, C-3), 79.5 (C-30),
81.3 (C-50), 93.2 (C-1), 105.1 (C-20); trans-p-coumaroyl units: R1: 21.0
(C-1100), 118.7 (C-800), 123.5 (C-300, C-500), 130.6 (C-200, C-600), 133.5
(C-100), 145.7 (C-700), 154.0 (C-400), 167.7 (C-900), 170.9 (C-1000), R2:
21.0 (C-1100), 118.8 (C-800), 123.5 (C-300, C-500), 130.8 (C-200, C-600), 133.5
(C-100), 146.2 (C-700), 154.0 (C-400), 168.4 (C-900), 170.9 (C-1000);
(75.48 MHz, CD3OD):
d
61.3 (C-6), 64.3 (C-10, C-60), 69.4 (C-4), 71.7
(C-2), 73.1 (C-5), 73.9 (C-3), 76.7 (C-40), 77.2 (C-30), 79.4 (C-50), 92.4
(C-1); 105.5 (C-20); trans-cinnamoyl units: R1: 116.6 (C-800),
128.3 (C-300, C-500),128.8 (C-200, C-600),130.4 (C-400),134.0 (C-100),145.9

10
P. Panda et al. / European Journal of Medicinal Chemistry 53 (2012) 1e12
ESI-Mass (positive mode): m/z 741.22 [M þ Na]þ, calcd 741.21 for
C34H38O17Na; HReESIeMS (positive mode): found m/z 741.2001
[M þ Na]þ, calcd 741.2001 for C34H38O17Na. Anal. Calcd for
C34H38O17: C, 56.28; H, 5.33; found: C, 56.23; H, 5.49.
J ¼ 9.6 Hz, 9.3 Hz, H-3), 5.38 (d, 1H, J ¼ 5.4 Hz, H-40), 5.61 (br dd,
1H, J ¼ 4.8 Hz, 3.3 Hz, H-30), 6.18 (d, 1H, J ¼ 3.3 Hz, H-1); trans-
cinnamoyl units: R1: 6.45 (d, 1H, J ¼ 16.2 Hz, H-800), 7.30e7.39
(m, 3H, H-300, H-400, H-500), 7.48e7.52 (m, 2H, H-200, H-600), 7.70
(d, 1H, J ¼ 16.2 Hz, H-700); R2: 6.45 (d, 1H, J ¼ 16.2 Hz, H-800),
7.30e7.39 (m, 3H, H-300, H-400, H-500), 7.48e7.52 (m, 2H, H-200,
H-600), 7.72 (d, 1H, J ¼ 16.2 Hz, H-700); R3: 6.60 (d, 1H, J ¼ 15.9 Hz,
H-800), 7.30e7.39 (m, 3H, H-300, H-400, H-500), 7.62e7.67 (m, 2H,
H-200, H-600), 7.92 (d, 1H, J ¼ 15.9 Hz, H-700); 13C NMR (75.48 MHz,
4.1.3. General procedure 2: acetylation of compounds 9 and 10
To a stirred solution of the cinnamoylated compound (1.0 g) in
dry pyridine (10 mL per mmol) was added excess Ac2O (0.6 mL per
mmol) dropwise. The mixture was stirred at rt for 24 h (TLC, 1:2
EtOAc-hexanes). The resulting mixture was then poured into
vigorously stirred ice-water (200 mL) and the white solid precipi-
tated was filtered using a Buchner funnel. The precipitate was
redissolved in EtOAc (50 mL). The aqueous layer was back extracted
with EtOAc (2 ꢂ 50 mL) and combined with the original organic
layer. The organic solution was washed with 1N HCl (100 mL), 5%
NaHCO3 (2 ꢂ 100 mL), brine (100 mL) and then dried over anhy-
drous MgSO4 before being filtered. The EtOAc filtrates were
concentrated under vacuum and acetylated compounds were
obtained as an off-white solid.
CDCl3):
d
19.0, 23.9, 25.4, 29.1 (4 ꢂ (CH3)2C), 21.0 (C-1100), 62.1
(C-6), 64.3 (C-5), 65.0 (C-60), 66.2 (C-10), 70.7 (C-3), 71.5 (C-4), 71.8
(C-2), 77.4 (C-40), 77.7 (C-30), 80.2 (C-50), 91.6 (C-1), 99.5, (101.4
(2 ꢂ CH3)2C), 105.0 (C-20); trans-cinnamoyl units: R1: 116.4 (C-800),
128.1 (C-200, C-600), 128.7 (C-300, C-500), 130.3 (C-400), 134.0 (C-100),
145.2 (C-700), 165. 9 (C-900), R2: 116.7 (C-800), 128.1 (C-200, C-600),
128.8 (C-300, C-500), 130.5 (C-400), 134.3 (C-100), 146.4 (C-700), 166.1
(C-900), R3: 117.7 (C-800), 128.3 (C-200, C-600), 128.9 (C-300, C-500), 130.7
(C-400), 134.4 (C-100), 147.4 (C-700), 166.4 (C-900), 169.7 (C-1000);
ESI-Mass (positive mode): m/z 877.36 [M þ Na]þ, calcd 877.31 for
C47H50O15Na; HReESIeMS (positive mode): found m/z 877.3051
[M þ Na]þ, calcd 877.3042 for C47H50O15Na; Anal. Calcd for
C47H50O15: C, 66.03; H, 5.90; found: C, 66.45; H, 6.27.
4.1.3.1. 3,40-Di-O-acetyl-30,60-di-O-cinnamoyl-2,10:4,6e2,10:4,6-di-O-
isopropylidene sucrose 21. Following general procedure 2, reaction
between compound 9 (0.6 g, 0.9 mmol) and Ac2O (0.6 mL, 0.7 g,
6.5 mmol) in pyridine (5.0 mL) for 24 h gave compound 21 (0.6 g,
88% yield) as white solid. Analytical data for 21: Rf ¼ 0.91 (3:1
EtOAc-hexanes); mp 88e90 ꢁC; FTeIR (KBr) nmax cmꢀ1: 3471, 3418,
2993, 2942, 1753, 1720, 1637, 1579, 1497, 1451, 1371, 1312, 1233,
1203, 1159, 1072, 1049, 990, 946, 893, 860, 769, 712, 685; 1H NMR
4.1.4. General procedure 4: preparation of compounds 1 and 23
Pyrrolidine (3 mol equiv per acetyl group) was added dropwise
to a stirred suspension of acetylated compound 20 or compound
15 (1 mmol) in 95% EtOH (40.0 mL) causing the mixture to turn
yellow. The acetylated compound typically dissolved within
15 min and the reaction was allowed to continue at rt for a total of
1e2 h (TLC, 3:1 EtOAC-hexanes). The crude reaction mixture was
then poured directly to a column of strongly acidic ion-exchange
resin [Amberlite IRA-120 (Hþ), washed and packed in 95%
EtOH]. The appropriate fraction was then collected and concen-
trated to a residue under reduced pressure. The residue was
subjected to silica gel column chromatography using a gradient of
CH2Cl2-EtOAc-MeOH as eluent. The appropriate fraction was
evaporated under reduced pressure to furnish the product as
a white solid. The general procedure was used to prepare
compounds 1 and 23.
(300 MHz, CDCl3):
d
1.20, 1.29, 1.42, 1.46 (4 ꢂ s, 12H, (CH3)2C), 2.02,
2.11 (2 ꢂ s, 6H, -COCH3), 3.60 (m, 2H, H-10a, H-4), 3.68 (d, 1H,
J ¼ 10.5 Hz, H-6a), 3.80e3.92 (m, 2H, H-2, H-5), 4.00 (dd, 1H,
J ¼ 5.1 Hz, 10.2 Hz, H-6b), 4.18 (d, 1H, J ¼ 12.3 Hz, H-10b), 4.42
(m, 1H, H-60a), 4.51 (m, 2H, H-50, H-60b), 5.20e5.28 (m, 2H, H-30,
H-3), 5.45 (dd, 1H, J ¼ 3.6 Hz, 5.1 Hz, H-40), 6.14 (d, 1 H, J ¼ 3.3 Hz,
H-1); trans-cinnamoyl units: R1: 6.46 (d, 1H, J ¼ 16.2 Hz, H-800),
7.36e7.40 (m, 3H, H-300, H-400, H-500), 7.51e7.54 (m, 2H, H-200, H-600),
7.71 (d, 1H, J ¼ 16.2 Hz, H-700); R2: 6.58 (d, 1H, J ¼ 16.2 Hz, H-800),
7.36e7.40 (m, 3H, H-300, H-400, H-500), 7.63e7.66 (m, 2H, H-200, H-600),
7.90 (d, 1H, J ¼ 16.2 Hz, H-700); 13C NMR (75.48 MHz, CDCl3):
d 19.0,
23.9, 25.5, 28.8 (4 ꢂ (CH3)2C), 20.8, 21.0 (2 ꢂ C-1100), 62.1 (C-6),
64.2 (C-5), 64.9 (C-60), 66.1 (C-10), 70.7 (C-3), 71.5 (C-4), 71.8 (C-2),
77.29 (C-40), 77.5 (C-30), 80.2 (C-50), 91.6 (C-1), 99.5, 101.4
(2 ꢂ (CH3)2C), 104.9 (C-20); trans-cinnamoyl units: R1: 116.4 (C-800),
128.1 (C-200, C-600), 128.8 (C-300, C-500), 130.3 (C-400), 134.2 (C-100);
145.2 (C-700); 166.1 (C-900); R2: 117.7 (C-800), 128.7 (C-200, C-600), 128.9
(C-300, C-500), 130.5 (C-400), 134.4 (C-100); 147.4 (C-700); 166.5 (C-900),
169.7, 170.1 (2 ꢂ C-1000); ESI-Mass (positive mode): m/z 789.34
[M þ Na]þ, calcd 789.28 for C40H46O15Na; HReESIeMS (positive
mode): found m/z 789.2727 [M þ Na]þ, calcd 789.2729 for
C54H54O15Na; Anal. Calcd for C40H46O15: C, 62.65; H, 6.05; found:
C, 62.22; H, 6.33.
4.1.4.1. Preparation of lapathoside D 1. Following general procedure
4, a suspension of compound 20 (0.5 g, 0.7 mmol) in 95% EtOH
(21 mL) was treated with pyrrolidine (325.0
mL, 281.4 mg,
4.0 mmol) for a total of 2 h. The reaction mixture afforded
compound 1 (0.31 g, 70% yield) as white solid. Analytical data for 1:
Rf ¼ 0.55 (15:1 EtOAc-MeOH); mp 98e100 ꢁC; FTeIR (KBr) nmax
:
3304, 2938, 1706, 1636, 1606, 1516, 1438, 1330, 1264, 1204, 1171,
1062, 1002, 863, 831 cmꢀ1 1H NMR (300 MHz, CD3OD):
; d 3.41
(m, 1H, H-4), 3.44 (m, 1H, H-2), 3.61 (m, 2H, H-10b, H-10a), 3.63 (m,
1H, H-3), 3.80 (m, 1H, H-6a), 3.91 (m, 2H, H-6b, H-5), 4.15 (m, 1H, H-
50), 4.43 (dd, 1H, J ¼ 7.8 Hz, 8.1 Hz, H-40), 4.54 (m, 2H, H-60b, H-60a),
5.44 (d, 1H, J ¼ 3.6 Hz, H-1), 5.49 (d, 1H, J ¼ 8.1 Hz, H-30); trans-p-
coumaroyl units: R1: 6.41 (d, 1H, J ¼ 15.9 Hz, H-800), 6.81 (d, 2H,
J ¼ 8.4 Hz, H-300, H-500), 7.52 (d, 2H, J ¼ 9.0 Hz, H-200, H-600), 7.72 (d,
1H, J ¼ 15.9 Hz, H-700); R2: 6.37 (d, 1H, J ¼ 15.9 Hz, H-800), 6.81 (d, 2H,
J ¼ 8.4 Hz, H-300, H-500), 7.48 (d, 2H, J ¼ 9 Hz, H-200, H-600), 7.67 (d, 1H,
4.1.3.2. 3-O-Acetyl-30,40,60-tri-O-cinnamoyl-2,10:4,6-di-O-iso-
propylidene sucrose 22. Following general procedure 2, reaction
between 10 (1.1 g, 1.4 mmol) and acetic anhydride (0.8 mL, 0.9 g,
8.9 mmol) in pyridine (10 mL) for 24 h gave compound 22 (1.0 g,
86% yield) as white solid. Analytical data for 22: Rf ¼ 0.94 (3:1
EtOAc-hexanes); mp 132e134 ꢁC; FTeIR (KBr) nmax: 3336, 2927,
1765, 1701, 1636, 1601, 1507, 1374, 1323, 1284, 1209, 1167, 1063,
994, 915, 860, 838, 794, 694, 650 cmꢀ1; 1H NMR (300 MHz, CDCl3):
J ¼ 15.9 Hz, H-700); 13C NMR (75.48 MHz, CD3OD):
d 62.6 (C-6), 65.1
(C-10), 66.4 (C-60), 71.4 (C-4), 73.2 (C-2), 74.4 (C-5), 75.0 (C-40, C-3),
79.3 (C-30), 81.2 (C-50), 93.2 (C-1), 105.1 (C-20); trans-p-coumaroyl
units: R1: 114.6 (C-800),116.9 (C-300, C-500),127.2 (C-100),131.5 (C-200, C-
600); 147.6 (C-700),161.3 (C-400),168.4 (C-900), R2: 114.8 (C-800),116.9 (C-
300, C-500), 127.2 (C-100), 131.3 (C-200, C-600); 147.0 (C-700), 161.3þ(C-400),
169.2 (C-900); ESI-Mass (positive mode): m/z 657.1 [M þ Na] , calcd
657.1 for C30H34O15Na; HReESIeMS (positive mode): found m/z
657.1786 [M þ Na]þ, calcd 657.1790 for C30H34O15Na; Anal. Calcd for
d
1.19, 1.31, 1.42, 1.47 (4 ꢂ s, 12H, (CH3)2C), 2.02 (1s, 3H, -COCH3),
3.57 (m, 1H, H-4), 3.64 (m, 1H, H-10a), 3.70 (d, 1H, J ¼ 10.5 Hz, H-
6a), 3.85 (dd, 1H, J ¼ 3.3 Hz, 9.3 Hz, H-2), 3.92 (m, 1H, H-5), 4.04
(dd, 1H, J ¼ 5.1 Hz, 10.5 Hz, H-6b), 4.23 (d, 1H, J ¼ 12.3 Hz, H-10b),
4.54 (m, 2H, H-50, H-60a), 4.61 (m, 1H, H-60b), 5.25 (dd, 1H,

P. Panda et al. / European Journal of Medicinal Chemistry 53 (2012) 1e12
11
C30H34O15: C, 56.78; H, 5.40; found: C, 55.31; H, 6.12. Spectral data
of compound 1 was the same as reported previously [8].
(testing drug)/Net A490 (control)) x 100%. Hence, the negative
control was set to 100% survival or 0% toxicity. IC50 is the concen-
tration that induces 50% growth inhibition compared with
untreated control cells. The IC50 values of the screened PSEs were
calculated from the doseeresponse curve by non-linear regression
analysis using the data analysis software (Graph Pad Prism) from
three independent experiments. Comparisons between multiple
groups were carried out using one-way analysis of variance (one-
way ANOVA) with Bonferroni’s correction. Differences were
considered statistically significant when P < 0.05.
4.1.4.2. 30,40,60-Tri-O-coumaroyl-2,10:4,6-di-O-isopropylidene sucrose
23. Following general procedure 4, a suspension of compound 15
(0.1 g, 0.1 mmol) in 95% EtOH (4.0 mL) was stirred with pyrrolidine
(97.5 mL, 84.4 mg, 1.2 mmol) for a total of 1 h. The reaction mixture
afforded compound 23 (0.04 g, 46% yield) as white solid. Analytical
data for 23: Rf ¼ 0.57 (9:1 EtOAc-MeOH); mp 115e118 ꢁC; FTeIR
(KBr) nmax: 3290, 1700, 1632, 1605 1515, 1443, 1374, 1330, 1263,
1204, 1170, 1106, 1057, 995, 864, 830 cmꢀ1 1H NMR (300 MHz,
;
CD3OD):
d
1.24, 1.33, 1.44 (3 ꢂ s, 12H, (CH3)2C), 3.52 (m, 1H, H-4);
Acknowledgments
3.68 (m, 4H, H-2, H-3, H-10a, H-6a), 3.78 (m, 1H, H-5), 3.96 (m, 1H,
H-6b), 4.20 (m, 1H, H-10b), 4.46 (m, 2H, H-50, H-60a), 4.59 (m, 1H,
H-60b), 5.33 (br s, 1H, H-40), 5.60 (br s, 1H, H-30), 6.09 (br s, 1H, H-1);
trans-p-coumaroyl units: R1: 6.26e6.42 (m, 1H, H-800), 6.72e6.80
(m, 2H, H-300, H-500), 7.39 (m, 2H, H-200, H-600), 7.63 (m, 1H, H-700),
R2: 6.26e6.42 (m, 1H, H-800), 6.72e6.80 (m, 2H, H-300, H-500), 7.39
(m, 2H, H-200, H-600), 7.63 (m, 1H, H-700), R3: 6.26e6.42 (m, 1H, H-800),
6.72e6.80 (m, 2H, H-300, H-500), 7.52 (m, 2H, H-200, H-600), 7.75 (m,1H,
This research was supported by a grant from the National
Medical Research Council (NMRC), Singapore (EDG10nv043). The
authors wish to thank Ms Tang Siang Ning, Ms Foong Sook Ching,
Ms Liu Kaiwen Ivy and Ms Teo Yat Lin for their very helpful
contribution during the synthesizing these compounds.
Supplementary data
H-700); 13C NMR (75.48 MHz, CD3OD):
d 19.5, 24.4, 25.8, 29.5
(4 ꢂ (CH3)2C), 63.3 (C-6), 65.4 (C-5), 66.1 (C-60), 67.6 (C-10), 71.3
(C-3), 74.6 (C-4), 75.1 (C-2), 79.0 (C-40), 79.3 (C-30), 81.2 (C-50), 93.1
(C-1), 101.0, 103.0 (2 ꢂ (CH3)2C), 106.5 (C-20); trans-p-coumaroyl
units: R1: 114.0 (C-800), 116.9 (C-300,C-500), 127.1 (C-100), 131.4 (C-200,
C-600), 147.0 (C-700), 161.3 (C-400), 168.0 (C-900), R2: 114.2 (C-800), 117.0
(C-300, C-500), 127.1 (C-100), 131.7 (C-200, C-600), 148.1 (C-700), 161.6
(C-400), 168.3 (C-900), R3: 115.0 (C-800), 117.0 (C-300, C-500), 127.2 (C-100),
131.9 (C-200, C-600), 148.5 (C-700), 161.6 (C-400), 168.8 (C-900);
HReESIeMS (positive mode): found m/z 883.2793 [M þ Na]þ, calcd
883.2784 for C45H48O17Na.
Supplementary data associated with this article can be found in
the online version, at doi:10.1016/j.ejmech.2012.02.032. These data
include MOL files and InChiKeys of the most important compounds
described in this article.
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m
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cytotoxicity (or growth inhibition) was calculated as (1-(Net A490

12
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