Synthesis of pentasaccharide and heptasaccharide derivatives and their effects on plant growth

Article abstract of DOI:10.1021/jf800326r

Two oligosaccharide derivatives, β-D-Glcp-(1-6)-β-D-Glcp-(1-6)- β-D-Glcp-(1-6)-β-D-Glcp-(1-4)-α-D-ManpOMe (1) and β-D-Glcp-(1-6)-β-D-Glcp-(1-6)-β-D-Glcp-(1-6)-β-D-Glcp-(1-6) -β-D-Glcp-(1-6)-β-D-Glcp-(1-4)-α-D-ManpOMe (2), have been synthesized efficiently using a convergent glycosylation strategy of 2 + 3 and 2 + 5.1,6-Anhydro-β-D-glucopyranose, which was prepared from cotton pyrolysis, was applied as a key synthon in the synthesis, significantly simplifying the preparation. The bioassay suggested that these two oligosaccharides can both stimulate the growth of maize cultured in liquid medium at a concentration of 3 ppm.

Full text of DOI:10.1021/jf800326r

5634 J. Agric. Food Chem. 2008, 56, 5634–5638
Synthesis of Pentasaccharide and Heptasaccharide
Derivatives and Their Effects on Plant Growth
HONGMEI LIU,†,§ SHUIHONG CHENG,‡,§ JUN LIU,‡ YUGUANG DU,*,† ZHIHUI BAI,‡
AND YUGUO DU*,‡
The Natural Products and Glycoconjugate Research Group 1805, Dalian Institute of Chemical Physics,
Chinese Academy of Sciences, Dalian 116023, China, State Key Laboratory of Environmental
Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of
Sciences, Beijing 100085, China, and Graduate University of the Chinese Academy of Sciences, China
Two oligosaccharide derivatives, ꢀ-D-Glcp-(1-6)-ꢀ-D-Glcp-(1-6)-ꢀ-D-Glcp-(1-6)-ꢀ-D-Glcp-(1-4)-R-
D-ManpOMe (1) and ꢀ-D-Glcp-(1-6)-ꢀ-D-Glcp-(1-6)-ꢀ-D-Glcp-(1-6) -ꢀ-D-Glcp-(1-6)-ꢀ-D-Glcp-(1-6)-
ꢀ-D-Glcp-(1-4)-R-D-ManpOMe (2), have been synthesized efficiently using a convergent glycosylation
strategy of 2 + 3 and 2 + 5. 1,6-Anhydro-ꢀ-D-glucopyranose, which was prepared from cotton pyrolysis,
was applied as a key synthon in the synthesis, significantly simplifying the preparation. The bioassay
suggested that these two oligosaccharides can both stimulate the growth of maize cultured in liquid
medium at a concentration of 3 ppm.
KEYWORDS: Oligosaccharide; synthesis; plant growth; maize
INTRODUCTION
spectra analyses, as D-Glc-(1-6)-ꢀ-D-Glc-(1-6)-ꢀ-D-Glc-(1-6)-
ꢀ-D-Glc-(1-6)-Glc-(1-6)-ꢀ-D-Glc-(1-4)-R-D-Man and D-Glc-
(1-6)-ꢀ-D-Glc-(1-6)-ꢀ-D-Glc-(1-6)-ꢀ-D-Glc-(1-6)-ꢀ-D-Glc-
(1-6)- Glc-(1-6)-ꢀ-D-Glc-(1-4)-R-D-Man, respectively. Primary
bioactivity testing suggests that HS and OS may have plant
growth regulatory activity in plant tissue cultures (9, 10). We
hereby describe a practical method in the preparation of HS
analogues, pentasaccharide ꢀ-D-Glcp-(1-6)-ꢀ-D-Glcp-(1-6)-
ꢀ-D-Glcp-(1-6)-ꢀ-D- Glcp-(1-4)-R-D-ManpOMe (1) and hep-
tasaccharide ꢀ-D-Glcp-(1-6)-ꢀ-D-Glcp-(1-6)-ꢀ-D-Glcp-(1-6)-
ꢀ-D-Glcp-(1-6)-ꢀ-D-Glcp-(1-6)-ꢀ-D-Glcp-(1-4)-R-D-
ManpOMe (2) (Scheme 1), and disclose our primary results
on maize growth after treating with 1 and 2.
Various synthetic and naturally derived fungicides, bacteri-
cides, and antiviral agents have been used to prevent crops from
infection by pathogens without deleteriously affecting their
growth and ultimate harvesting. Although such compositions
are effective, there have been more and more concerns from
consumers regarding the potential harmful side effects of
chemical agents. This, in turn, has led people to pay more
attention to products of natural origin with less likely adverse
side effects (1–3).
Oligosaccharides, that can exert signaling effects on plant
tissues at very low concentration, are termed as oligosaccharins.
Some of them are elicitors for they induce a response that may
help the plant resist disease, while some have effects on plant
growth and development, which are described as nontraditional
plant hormones such as pectic oligosaccharins and xyloglucan
oligosaccharins. Despite some oligosaccharins as plant hormones
are ensured, there is still an urgent need to add flesh to our
skeletal understanding of oligosaccharins, including the discov-
ery of new biological effects (4–8). Two oligosaccharides,
heptasaccharide (HS) and octasaccharide (OS), were isolated
from the water extract of the rhizomes of Paris polyphylla var.
yunnanensis. They were identified as linear oligomers, composed
of glucose and mannose residues. The structures of compounds
HS and OS were elucidated, on the basis of NMR and mass
In our ongoing project, we found an efficient method for the
synthesis of ꢀ-D-(1f6)-linked gluco-oligosaccharides using
levoglucose, which was prepared from cotton pyrolysis (11) as
starting material. Thus, 1,6-anhydro-ꢀ-D-glucose (levoglucose,
3) was benzylated in DMF with benzyl bromide and NaH
affording 1,6-anhydro-2,3,4-tri-O-benzyl-ꢀ-D-glucopyranose (4).
Treatment of 4 with 2-propanethiol and BF3 ·Et2O in refluxed
CH2Cl2 obtained isopropyl 2,3,4-tri-O-benzyl-1-thio-D-glucopy-
ranoside (5) as an R product in 56% yield over two steps. The
1
small J1,2 value (5.5 Hz) at 5.34 ppm on the related H NMR
spectrum clearly indicated the correct structure of 5. Conver-
Scheme 1
* To whom correspondence should be addressed. E-mail: duyg@
dicp.ac.cn (Yuguang Du); duyuguo@rcees.cn (Yuguo Du).
† Dalian Institute of Chemical Physics, Chinese Academy of
Sciences.
§ Graduate University of the Chinese Academy of Sciences.
‡ Research Center for Eco-Environmental Sciences, Chinese Acad-
emy of Sciences.
10.1021/jf800326r CCC: $40.75  2008 American Chemical Society
Published on Web 06/21/2008

Synthesis of Pentasaccharide and Heptasaccharide Derivatives
J. Agric. Food Chem., Vol. 56, No. 14, 2008 5635
Scheme 2
Scheme 3
Scheme 4
Scheme 5
gently, compound 3 was benzoylated with benzoyl chloride in
dry pyridine affording 1,6-anhydro-2,3,4-tri-O-benzoyl-ꢀ-D-
glucopyranose (6), followed by ring opening with 2-propanethiol
and BF3 ·Et2O in refluxed CH2Cl2, which furnished isopropyl
2,3,4-tri-O-benzoyl-1-thio-D-glucopyranoside (7) as an R,ꢀ
mixture (nR/nꢀ ≈ 6/1) in 47% yield over two steps (Scheme 2).
Acetolysis of 6 with Ac2O-AcOH-H2SO4 (1:1:0.1) in CH2Cl2
gave 1,6-di-O-acetyl-2,3,4-tri-O-benzoyl-ꢀ-D-glucopyranose (8),
which was then transformed into glycosyl donors 6-O-acetyl-
2,3,4-tri-O-benzoyl-a-D-glucopyranosyl trichloroacetimidate (9)
according to published methods in 91% yield over three steps
(12). Methyl 2,3,6-O-benzoyl-R-D-mannopyranoside (10) was
prepared from commercial available methyl D-mannoside via
4,6-O-benzylidenation, benzoylation, acid hydrolysis, and re-
gioselective 6-O-benzoylation in 76% yield (13) (Scheme 3).
Condensation of 5 with 9 in the presence of a catalytic amount
of trimethylsilyl trifluoromethanesulfonate (TMSOTf) in CH2Cl2
at -20 °C gave desired disaccharide, isopropyl 6-O-acetyl-2,3,4-
tri-O-benzoyl-ꢀ-D-glucopyranosyl-(1f6)-2,3,4-tri-O-benzyl-1-
thio-R-D-glucopyranoside (11), in excellent yield (98%). Cou-
pling of disaccharide thioglycosyl donor 11 and acceptor 10 in
CH2Cl2 at -20 °C in the presence of cocatalyst TMSOTf and
N-iodosuccinimide (NIS), afforded the expected R-linked trisac-
charide (12) in good yield (78%). A doublet at δ 5.44 ppm in
the 1H NMR spectrum supports the newly formed R-bond
between glucosyl units II and III. Regioselective deacetylation

5636 J. Agric. Food Chem., Vol. 56, No. 14, 2008
Table 1. 1H-NMR Data of Compounds 5-17
compds
Liu et al.
δ (ppm)
5
1.27 (d, 6H, J 6.7 Hz, (CH3)2), 2.90 (m, 1H, SCH), 5.34 (d, 1H, J 5.5 Hz, H1), 4.62 (d, 6H, J 11 Hz,
PhCH), 3.74 (dd, 1H, J 5.5 Hz, 9.8 Hz, H2), 3.50 (dd, 1H, J 9.8 Hz, 9.1 Hz, H3), 3.84 (t, 1H, J 9.1 Hz,
H4), 4.09 (m, 1H, H5), 3.73 (m, 2H, H6a, H6b), 7.25 (m, 15H, 3Ph).
7
1.23 (d, 6H, J 6.7 Hz, (CH3)2), 3.02 (m, 1H, CH), 6.01 (d, 1H, J 5.8 Hz, H1), 5.44 (dd, 1H, J 5.8 Hz,
10.3 Hz, H2), 5.48 (t, 1H, J 9.9 Hz, H3), 6.06 (t, 1H, J 9.9 Hz, H4), 4.46 (m, 1H, H5), 3.73 (m, 2H, H6a,
H6b), 7.26 (m, 15H, 3Ph); 1.23 (d, 1Hꢀ, J 6.7 Hz, (CH3)2), 3.22 (m, 0.15Hꢀ, SCH), 4.91 (d, 0.15Hꢀ, J
10.1 Hz, H1), 5.44 (t, 0.15Hꢀ, J 10.1 Hz, H2), 5.44 (t, 0.15Hꢀ, J 9.9 Hz, H3), 5.93 (t, 0.15Hꢀ, J 9.9 Hz,
H4), 3.73 (m, 0.45Hꢀ, H5, H6a, H6b), 7.26 (m, 2.5Hꢀ, 3Ph);
9
2.07 (s, 3H, CH3), 6.83 (d, 1H, J 3.0 Hz, H1), 5.58 (dd, 1H, J 3.6 Hz, 10.2 Hz, H2), 6.22 (t, 1H, J 10.0
Hz, H3), 5.72 (t, 1H, J 10.0 Hz, H4), 4.48 (m, 1H, H5), 4.27 (m, 2H, H6a, H6b), 8.7 (s, 1H, NH), 7.28 (m,
15H, 3Ph).
10
11
3.49 (s, 3H, CH3), 5.61 (s, 1H, H1), 4.93 (s, 1H, H2), 5.60- (dd, 1H, J 3.3 Hz, 12.4 Hz, H3), 4.26 (t, 1H,
J 9.6 Hz, H4), 4.08 (m, 1H, H5), 4.63 (dd, 1H, H6a), 4.87 (dd, 1H, H6b),7.29 (m, 15H, 3Ph).
I
1.24 (d, 6H, J 6.7 Hz, (CH3)2), 1.99 (s, 3H, CH3), 2.88 (m, 1H, SCH), 4.73 (d, 1H, J 7.8 Hz, H1 ), 5.54
I
I
(dd, 1H, J 8.0 Hz, 9.6 Hz, H2 ), 5.81 (t, 1H, J 9.6 Hz, H3 ), 5.56 (t, 1H, J 9.7 Hz, H4 ), 4.19 (m, 1H,
I
H5 ), 4.23 (m, 2H, H6aI, H6b ), 5.36 (1H, J 5.1 Hz, H1 ), 4.85, 4.41, 4.22 (d, 6H, J 11 Hz, PhCH2O), 3.67
I
I
II
II
II
II
(dd, 1H, J 5.1 Hz, 9.5 Hz, H2 ), 3.72 (t, 1H, J 9.6 Hz, H3 ), 3.40 (t, 1H, J 9.8 Hz, H4 ), 3.90 (m, 1H,
H5 ), 3.79 (m, 1H, H6aII), 4.12 (m, 1H, H6bII), 7.02 (m, 30H, 6Ph).
II
I
1.9 (s, 3H, CH3), 3.48 (s, 3H, OCH3), 4.55 (d, 1H, J 8.2 Hz, H1 ), 5.50 (dd, 1H, J8.0 Hz, 9.7 Hz, H2 ),
I
12
I
I
5.77 (t, 1H, J 9.6 Hz, H3 ), 5.53 (t, 1H, J 9.7 Hz, H4 ), 5.44 (d, 1H, J 3.6 Hz, H1 ), 3.24 (dd, 1H, J 3.6
II
Hz, 9.9 Hz, H2 ), 3.79 (t, 1H, J 9.6 Hz, H3 ), 3.33 (t, 1H, J 9.5 Hz, H4 ), 3.66 (m, 1H, H6aII), 3.78 (m,
II
II
II
2H, H5 , H6bII), 4.89 (d, 1H, J 1.4 Hz, H1III), 5.67 (dd, 1H, J1.9 Hz, 2.8 Hz, H2III), 5.89 (dd, 1H, J 9.6
II
Hz, 3.2 Hz, H3III), 4.70 (t, 1H, J 9.7 Hz, H4III), 4.03 (m, 8H, H5 , H5III, H6aI, H6bI, 4PhCH2O), 4.51 (d, 1H,
I
J 11 Hz, PhCH2O), 4.66 (d, 1H, J 11 Hz, PhCH2O), 4.55 (m, 1H, H6bIII), 4.89 (m, 1H, H6aIII), 6.93 (m,
45H, 9Ph).
1.18, 1.05 (d, 3H, J 7.8 Hz, (CH3)2), 1.07,1.15 (d, 0.8Hꢀ, J 6.9 Hz, (CH3)2), 1.93 (s, 3Ha`, CH3), 1.93 (s,
14
II
0.8Hꢀ, COCH3), 2.86 (m, 1H, SCH), 3.03 (m, 0.26Hꢀ, SCH), 5.78 (d, 1H, J6.1 Hz, H1 ), 4.87 (d, 1H,
I
I
II
7.8 Hz, H1 ), 4.93 (d, 0.25Hꢀ, J7.9 Hz, H1 ), 4.77 (d, 0.24Hꢀ, J10.0 Hz, H1 ).
I
II
15
17
2.01 (s, 3H, COCH3), 3.35 (s, 3H, OCH3), 4.86 (d, 1H, J 7.8 Hz, H1 ), 5.19 (d, 1H, J 7.7 Hz, H1 ), 4.36
(d, 1H, J 8.0 Hz, H1III), 5.02 (d, 1H, J 3.3 Hz, H1IV), 4.92 (d, 1H, J 1.6 Hz, H1V).
I
II
2.00 (s, 3H, CH3), 3.36 (s, 3H, CH3), 4.74 (d, 1H, J 7.7 Hz, H1 ), 4.96 (d, 1H, J 7.6 Hz, H1 ), 4.92 (d,
1H, J 8.0 Hz, H1III), 5.10 (d, 1H, J 7.9 Hz, H1IV), 4.32 (d, 1H, J 8.0 Hz, H1V), 4.96 (d, 1H, J 3.5 Hz,
H1VI), 4.94 (d, 1H, J 1.7 Hz, H1VII).
of 12 with HCl (gas) in MeOH/DCM (1:2, v/v) gave (13) as
the trisaccharide glycosyl acceptor in good yield (89%) (14)
(Scheme 4).
tion of 14 with 16 using the same reaction conditions as those
described in the preparation of 15 obtained heptasaccharide (17)
in 83% yield (Scheme 5). Global deprotection of compounds
15 and 17 (15–17) obtained pentasaccharide 1 and heptasac-
charide 2, respectively, in almost quantitative yields.
Condensation of 9 with 7 catalyzed by TMSOTf gave a key
intermediate 6-O-acetyl-2,3,4-tri-O-benzoyl-ꢀ-D-glucopyranosyl-
(1f6)-2,3,4-tri-O-benzoyl-1-thio-D-glucopyranoside (14) in 68%
yield as an R,ꢀ mixture (nR/nꢀ ≈ 4/1), which was directly used
for the next reaction without further purification. Coupling of
disaccharide glycosyl donor 14 with trisaccharide glycosyl
acceptor 13 was promoted with TMSOTf/NIS in CH2Cl2, giving
pentasaccharide (15) in an isolated yield of 80%. Removal of
6-O-deacetylation from 15 as described in the preparation of
13 afforded pentasaccharide glycosyl acceptor (16). Condensa-
MATERIALS AND METHODS
Instruments. 1H NMR and 13C NMR were recorded with a Bruker
ARX 400 spectrometer for the solutions in CDCl3 or D2O. The chemical
shifts are given in parts per million downfield from internal Me4Si.
Mass spectra were measured using a MALDI-TOF-MS with a-cyano-
4-hydroxycinnamic acid (CCA) as matrix or recorded with a VG
Figure 1. Mass of maize plant after exposure to oligosaccharides for
one and three weeks. The results are expressed as means (n ) 4). The
asterisk (*) indicates a significant difference from the control group (*, p
> 0.05; **, p > 0.01).
Figure 2. Effect on the growth of maize plants treated with
oligosaccharide for one week. The control is nutrient media, (a) is
nutrient media plus 3 ppm pentasaccharide, and (b) is nutrient media
plus 3 ppm heptasaccharide.

Synthesis of Pentasaccharide and Heptasaccharide Derivatives
J. Agric. Food Chem., Vol. 56, No. 14, 2008 5637
was added at -20 °C, and the mixture was stirred for 20 min at -20 °C.
TLC indicated that the reaction was complete. The reaction mixture
was then neutralized with Et3N and concentrated under reduced pressure
to dryness and purification of the crude product by column chroma-
1
tography. The H NMR of compounds 5-17 are listed in Table 1..
Bioassay. Maize seeds were immersed in 10% H2O2 (wt/wt) solution
for 10 min to avoid bacterium contamination and then in 0.1 M CaCl2
for 30 min to improve germination. Seeds were subsequently germinated
on moist filter paper in the dark at room temperature. Two days later,
the pregerminated seedlings with seminal leaves were transferred to
nutrient media containing 2.0 mM Ca(NO3)2 ·4H2O, 2.5 mM KNO3,
0.5 mM KH2PO4, 1.0 mM MgSO4 ·7H2O, 0.5 mM NH4NO3, 0.05 mM
FeSO4 ·7H2O, 0.83 mg/L KI, 8.6 mg/L ZnSO4, 6.2 mg/L H3BO3, 0.25
mg/L Na2MoO4, 22.3 mg/L MnSO4, 0.025 mg/L CuSO4, and 0.025
mg/L CoCl2. After the plants had grown for 3 days, the media were
then supplemented with oligosaccharides at 3 ppm. The media were
exchanged every day for fresh media containing oligosaccharides. At
the 7th and 21st day of plant growth, plants were wiped with tissue
paper and weighed (18–20). The role of oligosaccharides in growth
regulation is described in Figures 1-3.
Figure 3. Effect on the growth of maize roots treated with oligosaccharide
for three weeks. The control is nutrient media, (a) is nutrient media plus
3 ppm pentasaccharide, and (b) is nutrient media plus 3 ppm
heptasaccharide.
Scheme 6
RESULTS AND DISCUSSION
Synthesis. Compounds 5 and 7 were synthesized efficiently
using 1,6-anhydro-ꢀ-D-glucose (levoglucose), which was pre-
pared through pyrolysis of wasted cotton in our laboratory, as
the starting material. Nucleophilic attack on C-1 of protected
levoglucose by 2-propanethiol, with the help of boron trifluoride
etherate, significantly simplified the whole strategy as shown
in Scheme 2. Compounds 11-17 were prepared in good yield
as shown in Schemes 4 and 5.
Initially, we attempted to make the desired disaccharide 20
via a coupling reaction of 6-O-acetyl-2,3,4-tri-O-benzyl-R-D-
glucopyranosyl trichloroacetimidate (18) and 10, but failed. Only
decomposed 18 and unreacted 10 were found in the reaction
mixture. A condensation of isopropyl 6-O-acetyl-2,3,4-tri-O-
benzyl-1-thio-R-D-glucopyranoside (19) and 10 was also tried,
but was fruitless (Scheme 6). It is thus believed that active
glycosyl donor does not match with the unreactive acceptor in
our design strategies (21). Fortunately, a relatively inactive
disaccharide donor 11 was matched with 10; thus, we obtained
the desired trisaccharide 12 under the same reaction
conditions.
PLATFORM mass spectrometer using the ESI(-) technique to
introduce the sample. Thin-layer chromatography (TLC) was performed
on silica gel HF254 with detection by charring with 30% (v/v) H2SO4
in MeOH or in some cases by UV detector. Column chromatography
was conducted by elution of a column of silica gel (100-200 mesh)
with EtOAc-petroleum ether (60-90 °C) as the eluent. The solutions
were concentrated at <60 °C under reduced pressure.
General Synthetic Procedure for Compound 5. To a solution of
levoglucose 3 (2.0 g, 12.35 mmol) in DMF (20 mL) at 0 °C was added
NaH (1.77 g, 74.07 mmol), and the mixture was stirred at 0 °C for 30
min, then BnBr (5.90 mL, 49.38 mmol) was added. The mixture was
stirred at rt for 2 h. The reaction mixture was diluted with cold water
(50 mL) and extracted with EtOAc (150 mL). The organic phase was
dried over anhydrous Na2SO4 and concentrated. The residue was
purified by column chromatography (4:1 petroleum-EtOAc) to give
intermediate 4 (4.96 g, 93%) as a foamy solid. Solid 4 (4.5 g, 10.42
mmol) was dissolved in dry CH2Cl2 (40 mL) and (CH3)2CHSH (2.83
mL, 31.25 mmol), BF3 ·Et2O (2.64 mL, 20.83 mmol) was added, and
the mixture was refluxed for 1.5 h. The reaction mixture was neutralized
with saturated aq NaHCO3, then extracted with CH2Cl2. The organic
layer was dried and concentrated. Purification of the crude product by
column chromatography (4:1 petroleum-EtOAc) gave 5 (2.97 g, 56%)
as a foamy solid.
Effects on the Growth of Maize Plants. The results of
growth regulation activity tests given in Figures 1–3 show that
synthetic pentasaccharide and heptasaccharide promote the
growth of maize plants and also stimulate the growth of roots.
After supplementing with oligosaccharides for a week, pen-
tasaccharide increased the mass of plants by 21.4%, while
heptasaccharide increased the mass of plants by 10.7%. When
supplemented with oligosaccharides for 3 weeks, pentasaccha-
ride improved by 23.6%, and heptasaccharide improved by
32.7%. We also tested the effects of different concentrations of
oligosaccharides (3 ppm, 6 ppm, and 9 ppm) on the growth of
plants and found that high concentration did not improve the
growth rate more.
General Synthetic Procedure for Compounds 2-4. Levoglucose
was benzoylated following a reported literature procedure (12), and
the following step was the same as the description in the procedure for
making compound 5. Compounds 9 and 10 were prepared following
reported literature procedures (12, 13).
Synthetic Procedure for the Coupling Reaction. Donor and
acceptor were dried together under high vacuum for 1 h, then dissolved
in anhydrous CH2Cl2 with N2 protection. TMSOTf (or TMSOTf /NIS)
Table 2. Chemical Characteristics of Compounds 1 and 2
characteristics
1H NMR chemical shift δ (ppm)
compd 1
compd 2
4.32-4.44 (H1 , H1 ,H1III, H1IV, H1V), 5.08 (H1VI), 4.62
4.31-4.40 (H1 , H1 , H III), 5.08 (H1IV), 4.62 (H1V),
3.30 (OCH3)
102.6-103.0 (C1 , C1 , C1III), 100.7 (C1IV), 100.0
(C1
calcd for C31H54O26: 842.29
found 860 [M + NH4]+, 865 [M + Na]+
I
II
I
II
(H1VII), 3.31 (OCH3)
13C NMR chemical shift δ
(ppm)
ESI(+)-MS
102.6-103.0 (C1 , C1 , C1III, C1IV, C1V), 100.7 (C1VI),
I
II
I
II
V
)
VII
99.9 (C1 )
calcd for C43H74O36: 1166.39
found 1184 [M + NH4]+, 1189 [M + Na]+

5638 J. Agric. Food Chem., Vol. 56, No. 14, 2008
Liu et al.
(10) Zhou, L.; Cao, X.; Zhang, R.; Peng, Y.; Zhao, S.; Wu, J.
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In this article, we first synthesized pentasaccharide and
heptasaccharide derivatives 1 and 2. At present, there have been
no related reports about their plant growth activity. In the
bioassay, plant auxins such as 2,4-dichlorophenoxyacetic acid
and indole-3-acetic acid were used for positive control, but in
our experimental conditions, 2,4-dichlorophenoxyacetic acid
inhibited maize growth at a concentration of 3 ppm, and indole-
3-acetic acid did not have any effects on the growth of maize
at 3 ppm. The effect of glucose on maize growth was also tested,
but it did not have any effect at this concentration. Compared
with the known plant auxins, synthesized oligosaccharides may
have different mechanisms affecting the growth of maize.
ACKNOWLEDGMENT
(14) Gu, G.; Wei, G.; Du, Y. Synthesis of a 6(V)-sulfated mannopen-
tasaccharide analogue related to PI-88. Carbohydr. Res. 2004, 339
(6), 1155–62.
We thank Drs. Shuzhen Zhang and Yanhong Zhu from
RCEES of CAS for their helpful discussions.
(15) Adinolfi, M.; Barone, G.; Iadonisi, A.; Schiattarella, M. Removal
of benzyl protecting groups from controlled pore glass linked
sugars. Tetrahedron Lett. 2001, 42 (34), 5971–5972.
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charide a-D-Glcp-(1f3)-a-D-Manp-(1f2)-a-D-Manp-(1f2)-a-D-
Manp recognized by calreticulin/calnexin. Carbohydr. Res. 2005,
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Received for review February 20, 2008. Revised manuscript received
April 27, 2008. Accepted May 5, 2008. This work is supported by NNSF
20572128 and SKLECE Foundation, China.
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