Synthesis of the 6-deoxytalose-containing tri- and hexasaccharides of the O-antigen polysaccharide from Mesorhizobium huakuii IFO15243T

Article abstract of DOI:10.1016/j.carres.2010.07.023

The synthesis of a trisaccharide and a hexasaccharide, the monomer and dimer of the repeating unit of O-antigen polysaccharide from Mesorhizobium huakuii IFO15243, has been accomplished through suitable protecting group manipulations and stereoselective glycosylation reactions starting from commercially available l-rhamnose. The target oligosaccharides in the form of their p-methoxyphenyl glycosides are suitable for further glycoconjugate formation via selective cleavage of this group.

Full text of DOI:10.1016/j.carres.2010.07.023

Carbohydrate Research 345 (2010) 2067–2073
Contents lists available at ScienceDirect
Carbohydrate Research
journal homepage: www.elsevier.com/locate/carres
Note
Synthesis of the 6-deoxytalose-containing tri- and hexasaccharides
of the O-antigen polysaccharide from Mesorhizobium huakuii IFO15243T
a,
a
Guanghui Zong a, Yichen Feng a, Xiaomei Liang a, Liezhong Chen b, , Jianjun Zhang , Daoquan Wang
*
*
a Department of Applied Chemistry, China Agricultural University, Beijing 100 193, China
b Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310 021, China
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 3 June 2010
Received in revised form 8 July 2010
Accepted 10 July 2010
Available online 17 July 2010
The synthesis of a trisaccharide and a hexasaccharide, the monomer and dimer of the repeating unit of
O-antigen polysaccharide from Mesorhizobium huakuii IFO15243, has been accomplished through suit-
able protecting group manipulations and stereoselective glycosylation reactions starting from commer-
cially available
L-rhamnose. The target oligosaccharides in the form of their p-methoxyphenyl
glycosides are suitable for further glycoconjugate formation via selective cleavage of this group.
Ó 2010 Elsevier Ltd. All rights reserved.
Keywords:
L
-Rhamnose
6-Deoxy-a-L-talose
Oligosaccharide
Mesorhizobium huakuii
In Japan and the southern part of China, the winter growing,
green manure legumes renge-sou (Astragalus sinicus cv. Japan)
and Chinese milk vetch (A. sinicus cv. China), respectively, are
widely used as natural fertilizers of rice fields during the idle peri-
od. Mesorhizobium huakuii, a member of the Rhizobiaceae family iso-
lated from nodules of A. sinicus, is able to form nitrogen-fixing
symbiotic relationships with A. sinicus on the host roots and is of vi-
tal importance to the process of biological nitrogen fixation (BNF).1–3
As Gram-negative bacteria, their components, especially polysac-
charides, such as exopolysaccharides (EPSs), lipopolysaccharides
(LPSs), capsular polysaccharides (CPSs) and cyclic b-glucans, play
an important role during the free-living stage in soil environment
and especially during the development of symbiosis.4,5 The involve-
ment of the carbohydrate-rich molecules in establishing the interac-
tion between the BNF bacterium and the host has been reported,6,7
and it has been revealed that environmental conditions (in planta
and ex planta), as well as plant-derived molecular signals, are able
to induce entire LPS modifications in Rhizobium.8
genus.14 Generally, they are often composed of deoxysugars, meth-
ylated deoxysugars, uronic acids and heptosyl residues and some of
them may be highly acetylated. In certain rhizobial strains there are
polymers of repeating units.14–17 Whereas in other strains they are
homopolymers.14,18,19 These facts are of interest from the view-
points of the biological roles of carbohydrates, and to get a better
understanding of these plant–microbe interactions, synthetic stud-
ies on the LPSs will be useful. Choma et al.20 reported that the OPS of
M. huakuii IFO15243T was a linear polymer constituted of a trisac-
charide-repeating unit composed of the rare sugar of 6-deoxy-
L-
talose and -rhamnose (I in Fig. 1). Here we report the total synthesis
L
of the trisaccharide-repeating unit and its dimer (II and III, respec-
tively) of the OPS in the form of their p-methoxyphenyl glycosides.
The synthesis of the target oligosaccharides followed a conver-
gent, blockwise approach, relying on monosaccharide intermedi-
ates either described by us earlier or developed in this study. As
outlined in Scheme 1, known p-methoxylphenyl 3,4-di-O-ben-
zoyl-a-L
-rhamnopyranoside (1)21 was an ideal C-2-OH rhamnose
The O-antigenic polysaccharides (OPSs), which are present at the
distal part of LPSs, are in direct contact with the environment and are
closely involved in the process of exchanging signals between rhizo-
bia and legumes.9 Mutants having lipopolysaccharides that lack
their OPSs, or have modified core components, either are defective
in the formation of infection threads or have the nodules unoccu-
pied.10–13 The structures of OPSs show a high variability from genus
to genus of rhizobia and even from strain to strain within one
glycosyl acceptor. In addition, it was used as the starting material
for the preparation of the rhamnose glycosyl donor 3. Thus, com-
pound 1 was first reacted with AllocCl in the presence of pyridine
to afford the C-2-OH allyloxycarbonylated derivative 2 in 90%
yield. Next, removal of the anomeric methoxylphenyl group of 2
with ceric ammonium nitrate (CAN) in 80% CH3CN–H2O, followed
by trichloroacetimidate formation, provided trichloroacetimidate
3 in 75% yield over the two steps.
In our previous study we had developed an efficient procedure
for the preparation of p-methoxylphenyl 4-O-benzoyl-6-deoxy-
* Corresponding authors. Tel.: +86 10 62731115 (J.Z.).
E-mail address: zhangjianjun@cau.edu.cn (J. Zhang).
a-L-talopyranoside (4) from L
-rhamnose.22 Starting from this
0008-6215/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.carres.2010.07.023

2068
G. Zong et al. / Carbohydrate Research 345 (2010) 2067–2073
OH
Me
OH
Me
Me
Me
Me
Me
HO
HO
HO
HO
HO
HO
O
HO
O
HO
O
O
O
O
O
O
O
O
H
O
OPMP
O
HO
HO
n
n
I
n = 2
III
II
n = 1
Figure 1. Structure of the OPS of M. huakuii IFO15243T (I) and the synthesized tri- and hexasaccharide (II and III, respectively).
OCNHCCl3
OPMP
OPMP
Me
O
Me
O
BzO
BzO
b
Me
BzO
a
O
BzO
BzO
BzO
OAlloc
OAlloc
OH
3
2
1
OCNHCCl3
OPMP
OPMP
Me
c
b
O
Me
Me
O
O
BzO
HO
BzO
OR
OBz
c
OH
OBz
OBz
OBz
4
7
5 R = H
6 R = Bz
d
OCNHCCl3
OPMP
OPMP
Me
O
Me
O
Me
O
e
AllocO
OBz
AllocO
OBz
HO
OBz
OBz
OBz
10
8
9
OBz
b
Scheme 1. Reagents and conditions: (a) AllocCl, Py, DMAP, CH2Cl2, ꢀ10 °C, 3 h, 90%; (b) 4:1 CH3CN–H2O, CAN, 30 °C, then Cl3CCN, DBU, CH2Cl2, rt, 0.5 h, 75% for two steps for
3; 76% for two steps for 7; 88% for two steps for 10; (c) BzCl, Py, CH2Cl2, ꢀ10 °C, 3 h, 95% for 5; 94% for 6; (d) (i) AllocCl, Py, CH2Cl2, ꢀ10 °C, 0.5 h; (ii) BzCl, Py, CH2Cl2, ꢀ10 °C,
3 h, 82% over two steps; (e) CH3COONH4, Pd[P(C6H5)3]4, NaBH4, MeOH–THF, ꢀ10 °C, 4 min, 93% for 9.
material, a series of suitably protected 6-deoxy-
L
-talopyranose gly-
C-2-OH, the regioselectivity was not unexpected. Dibenzoate 8
was transformed into the corresponding glycosyl acceptor and
donor as follows: the allyloxycarbonyl group of 8 was successfully
removed in MeOH–THF26 in the presence of CH3COONH4,
Pd[P(C6H5)3]4 and NaBH4, within 4 min without affecting any of
the other protecting groups, giving the desired acceptor 9 in 93%
yield. The 1H NMR spectrum of compound 9 agreed with our pre-
viously reported data.24 Cleavage of the p-methoxyphenyl group
of 8 followed by conversion of the anomeric hydroxyl group to
the corresponding trichloroacetimidate derivative provided 3-O-
cosyl acceptors or donors were constructed. Thus, 4 was treated with
1.1 equiv of benzoyl chloride (the chloride was diluted with dichlo-
romethane and the solution was added slowly) in dichloromethane
at ꢀ10 °C in the presence of 20 equiv of pyridine and catalytic
amounts of DMAP, the C-3 hydroxyl group was then selectively
blocked to give 4-methoxyphenyl 3,4-di-O-benzoyl-6-deoxy-
a-L
-talopyranoside (5)22 in excellent yield (95%). Under the same
reaction conditions, if more benozyl chloride (another 1.5 equiv)
was added to the reaction mixture, 4-methoxyphenyl 2,3,4-tri-
O-benzoyl-6-deoxy-
a
-
L
-talopyranoside (6) was obtained. Cleavage
allyloxycarbonyl-2,4-di-O-benzoyl-
a
-
L
-talopyranosyl
trichloro-
of the 4-methoxyphenyl group of 6 with CAN, followed by the
acetimidate (10, 88%)25 conveniently.
reaction with trichloroacetonitrile and DBU,23 gave the 6-deoxy-
With the monosaccharide-building blocks in hand, synthesis of
the target tri- and hexasaccharide was achieved as shown in
Scheme 2. Glycosylation between rhamnosyl acceptor 1 and
6-deoxytalosyl donor 10 was accomplished by using TMSOTf as
the catalyst in the presence of 4 Å molecular sieves to afford
disaccharide 11 in 92% yield. The disaccharide 11 was reacted with
palladium catalyst (Pd[P(C6H5)3]4), NaBH4 and CH3COONH4 in
MeOH–THF26 to afford the disaccharide acceptor 12 in 88% yield.
Meanwhile, the coupling between 6-deoxytalosyl donor 7 and
acceptor 9 smoothly gave disaccharide 15, which was transformed
to the corresponding glycosyl donor 16 by CAN-promoted
4-methoxyphenyl deprotection and then conversion of the product
a-
L-talopyranose glycosyl trichloroacetimidate 7.
Meanwhile, treatment of 4 with allyloxycarbonyl chloride in
dichloromethane at ꢀ10 °C in the presence of 10 equiv of pyridine
and catalytic amounts of DMAP resulted in selective acylation of
the C-3 hydroxyl group to give p-methoxyphenyl 3-O-allyloxycar-
bonyl-6-deoxy-a-L-talopyranoside, which was benzoylated with
1.5 equiv of benzoyl chloride to provide p-methoxyphenyl 3-
O-allyloxycarbonyl-2,4-di-O-benzoyl-6-deoxy-a-L-talopyranoside
(8) in 82% yield. The 1H NMR spectrum of compound 8 was in
accordance with our previously reported data.24,25 Because the
equatorially oriented C-3-OH is more reactive than the axial

G. Zong et al. / Carbohydrate Research 345 (2010) 2067–2073
2069
OPMP
OCNHCCl3
OPMP
OPMP
b
Me
O
Me
O
Me
BzO
O
Me
BzO
O
1
7
+
9
BzO
O
OBz
BzO
O
OBz
a
OBz
O
c
OBz
a
O
+
Me
O
Me
O
Me
Me
O
O
10
HO
BzO
OBz
AllocO
OBz
BzO
OBz
OBz
OBz
OBz
OBz
OBz
13
14
12
11
Me
OPMP
OPMP
b
OR
BzO
O
Me
Me
O
BzO
Me
O
BzO
BzO
O
3
BzO
OBz
14, a
O
O
a
OBz
O
Me
O
BzO
+
5
Me
O
Me
BzO
Me
O
BzO
BzO
O
O
BzO
BzO
O
BzO
17 R = PMP
OH
BzO
OAlloc
Me
c
16
BzO
d
15
18 R = CNHCCl3
OBz
Me
BzO
BzO
Me
BzO
BzO
BzO
II
O
BzO
O
7, a
O
O
OPMP
O
BzO
19
12
OBz
Me
Me
BzO
Me
Me
BzO
BzO
Me
Me
O
18, a
d
BzO
BzO
O
III
BzO
BzO
BzO
O
BzO
O
BzO
O
O
O
O
O
O
OPMP
O
BzO
BzO
20
Scheme 2. Reagents and conditions: (a) TMSOTf, CH2Cl2, ꢀ10 °C to rt, 2 h, 92% for 11; 79% for 13; 81% for 15; 75% for 17; 77% for 19; 79% for 20; (b) CH3COONH4,
Pd[P(C6H5)3]4, NaBH4, MeOH–THF, ꢀ10 °C, 4 min, 88% for 12; 89% for 16; (c) 4:1 CH3CN–H2O, CAN, then Cl3CCN, DBU, CH2Cl2, rt, 72% for two steps for 14; 65% for two steps for
18; (d) satd NH3–MeOH, rt, 96 h, 84% for II; 81% for III.
hemiacetal to the trichloroacetimidate.23 Similar to the preparation
of 12, condensation of 3 with 5, followed by deallyloxycarbonyla-
tion of the resulting 15, successfully provided the disaccharide
acceptor 16. This disaccharide was further glycosylated with donor
14 to furnish the tetrasaccharide 17 in 75% yield. Cleavage of the
4-methoxyphenyl group of 17 with CAN followed by reaction with
trichloroacetonitrile and DBU provided the tetrasaccharide donor
18 in satisfactory overall yield (65%). Due to the poor solubility
of 17 in 4:1 CH3CN–H2O, cleavage of the 4-methoxyphenyl group
of 17 with CAN in this solvent system initially failed. To overcome
this problem, THF was added to the reaction mixture to increase
the solubility of the starting material and satisfactory results were
yielded the fully protected trisaccharide 19 in 77% yield (or hexa-
saccharide 20, 79%, respectively). Deacylation of trisaccharide 19
or hexasaccharide 20 with ammonia-saturated methanol afforded
the target trisaccharide II (84%), or hexasaccharide III (81%),
respectively.
In conclusion, the synthesis of a trisaccharide-repeating unit of
the LPS isolated from M. huakuii IFO15243T and its dimer has been
accomplished. Because the protecting group manipulation strate-
gies and glycosylation steps were selective and high-yielding, the
present synthetic strategy is capable of being carried out on reason-
ably large scale. Bioactivity investigations of trisaccharide II and
hexasaccharide III are in progress and the results will be reported
in due course.
obtained in CH3CN–THF–H2O 5:5:2, giving 2,3,4-tri-O-benzoyl-
6-deoxy-talopyranosyl-(1?3)-2,4-di-O-benzoyl- -6-deoxy-talo-
pyranosyl-(1?2)-3,4-di-O-benzoyl- -rhamnopyranosyl-(1?2)-
3,4-di-O-benzoyl- -6-deoxy-talopyranosyl-(1?3)-2,4-di-O-ben-
zoyl- -6-deoxy-talopyranosyl-(1?2)-3,4-di-O-benzoyl- ,b-
a-L-
a-L
a
-L
1. Experimental
a-L
a-
L
a
L-
1.1. General methods
rhamnopyranose as the sole product as indicated on TLC
detection.
Optical rotations were determined with a Perkin–Elmer model
241-MC automatic polarimeter for solution in a 1-dm, jacketed
Finally, condensation of the acceptor 12 with the donor 7 (or
18) following the same glycosylation strategy as mentioned above

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G. Zong et al. / Carbohydrate Research 345 (2010) 2067–2073
cell. 1H and 13C NMR spectra were recorded with Bruker DPX300
and Bruker AVANCE600 spectrometers in CDCl3 or D2O solutions.
Internal references: TMS (d 0.000 ppm for 1H), CDCl3 (d
77.00 ppm for 13C), HOD (d 4.700 for 1H). Elemental analysis was
performed on a Yanaco CHN Corder MF-3 automatic elemental
analyzer. Matrix-assisted laser-desorption ionization mass spectra
(MALDI MS) and electrospray-ionization mass spectra (ESIMS)
were performed by the Institute of Chemistry, Chinese Academy
of Sciences. Thin-layer chromatography (TLC) was performed on
silica gel HF with detection by charring with 30% (v/v) H2SO4 in
MeOH or by UV detection. Column chromatography was conducted
by elution of a column of silica gel (200–300 mesh) with EtOAc/PE
(bp 60–90 °C) as the eluent. Solutions were concentrated at a tem-
perature <60 °C under diminished pressure.
1.5. p-Methoxylphenyl 3-O-allyloxycarbonyl 2,4-di-O-benzoyl-
-6-deoxy-talopyranosyl-(1?2)-3,4-di-O-benzoyl-
rhamnopyranoside (11)
a-L
a-L-
To a cooled (ꢀ10 °C) solution of 1 (1.6 g, 3.3 mmol) and 10
(2.4 g, 4.0 mmol) in anhydrous, redistilled CH2Cl2 (40 mL) was
added 4 Å molecular sieves (3.0 g) and the mixture was stirred un-
der
a nitrogen atmosphere for 0.5 h. Then TMSOTf (27 lL,
0.15 mmol) was added and the mixture was stirred at ꢀ10 °C for
another 0.5 h, during which time the mixture was allowed to grad-
ually warm to ambient temperature. TLC (petroleum ether–EtOAc;
5:1, eluted twice) indicated that the reaction was complete. Then
the reaction mixture was neutralized with Et3N (two drops) and fil-
trated. The filtrate was evaporated under vacuum to give a residue
that was purified by column chromatography (petroleum ether–
EtOAc 6:1) to give disaccharide 11 as a white solid (2.8 g, 92%).
1.2. p-Methoxylphenyl 2,3,4-tri-O-benzoyl-a-L-6-deoxy-
talopyranoside (6)
½
a 2D5
ꢂ
ꢀ41 (c 1.0, CHCl3). 1H NMR (300 MHz, CDCl3) d: 8.11–7.12
(m, 20H, BzH), 7.12–7.09 (m, 2H, MpH), 6.91–6.88 (m, 2H, MpH),
6.02–5.89 (m, 2H, CH2@CHCH2OCO, H-3), 5.70–5.61 (m, 3H, H-20,
H-4, H-40), 5.53 (d, 1H, J1,2 = 1.8 Hz, H-1), 5.47 (dd, 1H,
Compound 522 (6.2 g, 13 mmol) was dissolved in pyridine
(20 mL), then benzoyl chloride (1.8 mL, 16 mmol) in CH2Cl2
(10 mL) was added dropwise to the solution over 30 min at
ꢀ10 °C. The reaction mixture was slowly raised to room tempera-
ture and stirred for 2 h, at the end of which time TLC (petroleum
ether–EtOAc, 3:1) indicated that the reaction was complete. The
reaction mixture was diluted with CH2Cl2 (100 ml), washed with
1 M HCl (50 mL), water (2 ꢁ 50 mL) and dried (Na2SO4). The sol-
vent was evaporated under vacuum and the residue was purified
by column chromatography (petroleum ether–EtOAc 4:1) to afford
J2 ,3 = J3 ,4 = 3.8 Hz, H-30), 5.39–5.23 (m, 3H, CH2@CHCH2OCO, H-
10), 4.71–4.68 (m, 2H, CH2@CHCH2OCO), 4.52–4.47 (m, 2H, H-2,
H-50), 4.24 (m, 1H, H-5), 3.80 (s, 3H, C6H4OCH3), 1.34, 1.29 (2d,
6H, J5,6 = 6.5 Hz, 2 ꢁ C-CH3). Anal. Calcd for C51H48O16: C, 66.80;
H, 5.28. Found: C, 66.96; H, 5.06.
0
0
0
0
1.6. p-Methoxylphenyl 2,4-di-O-benzoyl-
a
-L
-6-deoxy-
talopyranosyl-(1?2)-3,4-di-O-benzoyl-a-L-rhamnopyranoside
(12)
compound 6 (7.1 g, 94%) as a white solid. ½a D25
ꢂ
–84 (c 1.0, CHCl3). 1H
NMR (300 MHz, CDCl3) d: 8.12–7.18 (m, 15H, BzH), 7.12–7.09 (m,
2H, MpH), 6.89–6.86 (m, 2H, MpH), 5.98 (t, 1H, J2,3 = J3,4 = 4.0 Hz,
H-3), 5.76 (d, 1 H, J1,2 = 1.3 Hz, H-1), 5.73 (m, 1H, H-2), 5.67 (m,
1H, H-4), 4.55 (m, 1H, H-5), 3.79 (s, 3H, C6H4OCH3), 1.33 (d, 3H,
J5,6 = 6.5 Hz, C-CH3). Anal. Calcd for C34H30O9: C, 70.09; H, 5.19.
Found: C, 70.22; H, 5.35.
Compound 11 (2.0 g, 2.2 mmol) was de-O-allyloxycarbonylated
by following the same procedure as described for the preparation
of compound 9 to afford the disaccharide acceptor 12 (1.6 g, 88%)
as a foamy solid. ½a D25
ꢂ
–42 (c 1.0, CHCl3). 1H NMR (300 MHz, CDCl3)
d: 8.09–7.18 (m, 20H, BzH), 7.12–7.09 (m, 2H, MpH), 6.90–6.87 (m,
2H, MpH), 5.94 (dd, 1H, J2,3 = 3.2 Hz, J3,4 = 10.0 Hz, H-3), 5.63 (dd,
1H, J3,4 = J4,5 = 10.0 Hz, H-4), 5.56 (d, 1H, J1,2 = 1.8 Hz, H-1), 5.52–
5.48 (m, 2H, H-20, H-40), 5.28 (s, 1H, H-10), 4.62 (m, 1H, H-50),
4.49–4.43 (m, 2H, H-2, H-30), 4.24 (m, 1H, H-5), 3.80 (s, 3H,
C6H4OCH3), 3.01 (d, 1H, J = 6.4 Hz, OH), 1.32, 1.29 (2d, 6H,
J5,6 = 6.5 Hz, 2 ꢁ C-CH3); 13C NMR (75 MHz, CDCl3) d: 167.3,
166.4, 165.9, 165.6 (4 ꢁ COPh), 155.3, 150.2 (MpC), 133.2(3),
133.1, 130.0(2), 129.9(2), 129.8(2), 129.7(2), 129.6, 129.4, 129.3,
1.3. 2,3,4-Tri-O-benzoyl-a-L-6-deoxy-talopyranosyl
trichloroacetimidate (7)
Cleavage of the PMP group in 6 (6.2 g, 11 mmol) and conversion
to the trichloroacetimidate derivative were accomplished by fol-
lowing the same reaction protocol as described above for the prep-
aration of monosaccharide donor 3. After purification, donor 7
(5.0 g, 76% over 2 steps) was obtained as a white foam. ½a D25
ꢂ
ꢀ70
129.1,
128.4(2), 128.3(4),
128.1(2), 117.6(2),
114.8(2)
(c 1.0, CHCl3). 1H NMR (300 MHz, CDCl3) d: 8.82 (s, 1H, CNHCCl3),
8.10–7.21 (m, 15H, BzH), 6.61 (d, 1H, J1,2 = 1.4 Hz, H-1), 5.86 (dd,
1H, J2,3 = J3,4 = 4.0 Hz, H-3), 5.76 (d, 1H, J1,2 = J2,3 = 3.8 Hz, H-2),
5.71 (m, 1H, H-4), 4.63 (m, 1H, H-5), 1.39 (d, 3H, J5,6 = 6.5 Hz, C-
CH3). Anal. Calcd for C29H24Cl3NO8: C, 56.10; H, 3.90; N, 2.26.
Found: C, 55.82; H, 4.11; N, 2.46.
(MpC),100.5, 97.8 (2 ꢁ C-1), 72.2, 71.8, 70.9, 70.2, 67.9, 67.5, 66.1,
65.7, 55.7 (C6H4OCH3), 17.7, 16.6 (2 ꢁ C-CH3). Anal. Calcd for
C47H44O14: C, 67.78; H, 5.33. Found: C, 67.98; H, 5.40.
1.7. p-Methoxylphenyl 2,3,4-tri-O-benzoyl-
a-
L-6-deoxy-
talopyranosyl-(1?3)-2,4-di-O-benzoyl-a-L-6-deoxy-
talopyranoside (13)
1.4. 3-O-Allyloxycarbonyl 2,4-di-O-benzoyl-a-L-6-deoxy-
talopyranosyl trichloroacetimidate (10)
Glycosylation between monosaccharide acceptor 9 (2.1 g,
4.4 mmol) and donor 7 (3.3 g, 5.2 mmol) was accomplished by fol-
lowing the same reaction protocol as described above for the prep-
aration of disaccharide 11. After purification by column
chromatography (petroleum ether–EtOAc 5:1) 13 was obtained
Cleavage of the PMP group in 824,25 (4.3 g, 7.6 mmol) and con-
version to the trichloroacetimidate derivative were accomplished
by following the same reaction protocol as described in our previ-
ous work.25 After purification, the disaccharide donor 12 (4.0 g,
as a white solid (3.3 g, 79%). ½a D25
ꢂ
–168 (c 1.0, CHCl3). 1H NMR
88% over two steps) was obtained as a white foam. ½a D25
ꢂ
ꢀ51 (c
(300 MHz, CDCl3) d: 8.22–7.19 (m, 25H, BzH), 7.10–7.07 (m, 2H,
MpH), 6.89–6.86 (m, 2H, MpH), 5.74 (d, 1H, J1,2 = 1.4 Hz, H-1),
5.67 (m, 1H, H-40), 5.61–5.57 (m, 3H, H-2, H-10, H-20), 5.52 (dd,
1.0, CHCl3). 1H NMR (300 MHz, CDCl3) d: 8.81 (s, 1H, CNHCCl3),
8.15–7.20 (m, 10H, BzH), 6.56 (d, 1H, J1,2 = 1.5 Hz, H-1), 5.91 (m,
1H, CH2@CHCH2OCO), 5.70 (m, 1H, H-2), 5.63 (m, 1H, H-4), 5.45
(t, 1H, J2,3 = J3,4 = 3.7 Hz, H-3), 5.36–5.22 (m, 2H, CH2@CHCH2OCO),
4.68–4.64 (m, 2H, CH2@CHCH2OCO), 4.54 (m, 1H, H-5), 1.35 (d, 3H,
J5,6 = 6.5 Hz, C-CH3). Anal. Calcd for C26H24Cl3NO9: C, 51.97; H, 4.03;
N, 2.33. Found: C, 51.74; H, 4.21; N, 2.78.
1H, J2 ,3 = J3 ,4 = 4.0 Hz, H-30), 5.38 (m, 1H, H-4), 4.74 (dd, 1H,
J2,3 = J3,4 = 3.9 Hz, H-3), 4.52–4.42 (m, 2H, H-5, H-50), 3.79 (s, 3H,
C6H4OCH3), 1.32, 1.29 (2d, 6H, J5,6 = 6.5 Hz, 2 ꢁ C-CH3); 13C NMR
(75 MHz, CDCl3) d: 166.7, 166.6, 166.3, 165.7, 164.6 (5 ꢁ COPh),
155.3, 150.1(MpC), 133.2, 133.0, 132.9(2), 132.8, 130.2(2),
0
0
0
0

G. Zong et al. / Carbohydrate Research 345 (2010) 2067–2073
2071
130.1(2), 130.0(2), 129.9(2), 129.8(2), 129.6(4), 129.5, 128.4(2),
128.3(4), 128.2(2), 128.1(2), 117.7(2), 114.7(2) (MpC), 97.5(2)
(2 ꢁ C-1), 69.5, 69.4, 68.9, 68.2, 67.7, 66.4, 66.1, 65.9, 55.6
(C6H4OCH3), 16.5, 16.4 (2 ꢁ C-CH3). Anal. Calcd for C54H48O15: C,
69.22; H, 5.16. Found: C, 68.99; H, 5.04.
(2 ꢁ C-1), 72.3, 72.1, 71.7, 69.6, 69.3, 68.3, 67.5, 65.8, 55.7
(C6H4OCH3), 17.5, 16.2 (2 ꢁ C–CH3). Anal. Calcd for C47H44O14: C,
67.78; H, 5.33. Found: C, 68.03; H, 5.50.
1.11. p-Methoxylphenyl 2,3,4-tri-O-benzoyl-
pyranosyl-(1?3)-2,4-di-O-benzoyl- -6-deoxy-talopyranosyl-
(1?2)-3,4-di-O-benzoyl- -rhamnopyranosyl-(1?2)-3,4-di-O-
benzoyl- -6-deoxy-talopyranoside (17)
a-L-6-deoxy-talo-
a
-L
1.8. 2,3,4-Tri-O-benzoyl-
a-L
-6-deoxy-talopyranosyl-(1?3)-2,4-
a-L
di-O-benzoyl-
a-
L-6-deoxy- talopyranosyl trichloroacetimidate
a-L
(14)
Compound 16 (1.2 g, 1.5 mmol) and 14 (1.7 g, 1.7 mmol) were
glycosylated by following the same procedure as described above
for the preparation of disaccharide 11 to afford the tetrasaccharide
17 (1.8 g, 75%) as a white foam after purification by column chro-
Cleavage of the PMP group in 13 (3.1 g, 3.3 mmol) and conver-
sion to the trichloroacetimidate derivative were accomplished by
following the same reaction protocol as described above for the
preparation of 3. After purification by column chromatography
(petroleum ether–EtOAc 4:1) 14 (2.3 g, 72% over two steps) was
matography (petroleum ether–EtOAc 3:1). ½a D25
ꢂ
–25 (c 1.0, CHCl3).
1H NMR (300 MHz, CDCl3) d: 8.04–7.22 (m, 45H, BzH), 7.16–7.13
(m, 2H, MpH), 6.93–6.90 (m, 2H, MpH), 5.89–5.84 (m, 2H, H-3,
H-30), 5.72 (m, 2H, H-1, H-4), 5.60 (m, 1H, H-4), 5.58 (t, 1H,
obtained as a white foam. ½a D25
ꢂ
ꢀ124 (c 1.0, CHCl3). 1H NMR
(300 MHz, CDCl3) d: 8.82 (s, 1H, CNHCCl3), 8.22–7.18 (m, 25 H,
BzH), 6.60 (d, 1H, J1,2 = 1.4 Hz, H-1), 5.67 (m, 1H, H-40), 5.62-5.57
J3 ,4 = J4 ,5 = 10.0 Hz, H-40), 5.52 (s, 1H, H-1000), 5.49 (t, 1H,
0
0
0
0
(m, 3H, H-2, H-10, H-20), 5.52 (t, 1H, J2 ,3 = J3 ,4 = 4.0 Hz, H-30),
5.36 (m, 1H, H-4), 4.68 (dd, 1H, J2,3 = J3,4 = 3.9 Hz, H-3), 4.55–4.49
(m, 2H, H-5, H-50), 1.39, 1.28 (2d, 6H, J5,6 = 6.5 Hz, 2 ꢁ C-CH3). Anal.
Calcd for C49H42Cl3NO14: C, 60.35; H, 4.34; N, 1.44. Found: C, 60.02;
H, 4.32; N, 1.78.
J
= J
= 3.9 Hz, H-3000), 5.44 (m, 1H, H-200), 5.39 (m, 1H, H-
2000,3000
3000,4000
0
0
0
0
400), 5.35 (d, 1H, J 1 ,2 = 1.4 Hz, H-100), 5.32 (m, 1H, H-2000), 4.70 (d,
00 00
1H, J1 ,2 = 1.2 Hz, H-10), 4.57 (t, 1H, J 2 ,3 = J 3 ,4 = 3.8 Hz, H-300),
4.53–4.88 (m, 2H, 2 ꢁ H-5), 4.42 (m, 1H, H-2), 4.31–4.21 (m, 2H,
2 ꢁ H-5), 4.14 (m, 1H, H-20), 3.80 (s, 3H, C6H4OCH3), 1.35, 1.32
(2d, 12H, J5,6 = 6.5 Hz, 4 ꢁ C-CH3); 13C NMR (75 MHz, CDCl3) d:
166.5, 166.4, 166.3, 165.8, 165.7, 165.6, 165.5, 165.4, 164.6
(9 ꢁ COPh), 155.2, 150.2 (MpC), 133.3, 133.2, 133.1(2), 133.0,
132.9(2), 132.8, 132.7, 130.0(10), 129.9(2), 129.8(2), 129.7(4),
129.6(6), 129.5, 129.4, 129.3, 128.6(2), 128.5(2), 128.4(2),
128.3(2), 128.2(6), 128.1(2), 128.0(2), 117.5(2), 114.8(2) (MpC),
100.3, 99.8, 98.7, 96.9 (4 ꢁ C-1), 78.1, 72.3, 71.7, 70.8, 69.5, 69.3,
68.6, 68.5, 68.3, 68.0, 67.7, 67,4, 66.5, 66,1, 66.0, 65.9, 55.7
(C6H4OCH3), 17.7, 16.2, 16.2, 16.1 (4 ꢁ C-CH3). Anal. Calcd for
0
0
00 00
00 00
1.9. p-Methoxylphenyl 2-O-allyloxycarbonyl-3,4-di-O-benzoyl-
a-
L-rhamnopyranosyl-(1?2)-3,4-di-O-benzoyl-a-L-6-deoxy-
talopyranoside (15)
Glycosylation between monosaccharide acceptor
5 (2.6 g,
5.6 mmol) and donor 3 (4.0 g, 6.7 mmol) was accomplished by fol-
lowing the same reaction protocol as described above for the prep-
aration of disaccharide 11. After purification, the disaccharide 15
(4.2 g, 81%) was obtained as a white solid. ½a D25
ꢂ
+4.6 (c 1.0, CHCl3).
C94H84O27: C, 68.61; H, 5.14. Found: C, 68.94; H, 5.35.
1H NMR (300 MHz, CDCl3) d: 8.18–7.25 (m, 20H, BzH), 7.13–7.10
(m, 2H, MpH), 6.91–6.88 (m, 2H, MpH), 5.91–5.87 (m, 2H, H-3,
H-30), 5.78 (m, 1H, CH2@CHCH2OCO), 5.71–5.69 (m, 2H, H-10, H-
1.12. 2,3,4-Tri-O-benzoyl-
di-O-benzoyl- -6-deoxy- talopyranosyl-(1?2)-3,4-di-O-ben-
zoyl- -rhamnopyranosyl-(1?2)-3,4-di-O-benzoyl- -6-
deoxy-talopyranosyl trichloroacetimidate (18)
a-L-6-deoxy-talopyranosyl-(1?3)-2,4-
a-L
4), 5.54 (dd, 1H, J3 ,4 = J4 ,5 = 9.9 Hz, H-40), 5.29–5.15 (m, 2H,
CH2@CHCH2OCO), 5.20 (d, 1H, J1,2 = 1.7 Hz, H-1), 4.51–4.38 (m,
3H, CH2@CHCH2OCO, H-5), 4.34 (m, 1H, H-2), 4.27 (m, 1H, H-50),
3.80 (s, 3H, C6H4OCH3), 1.32, 1.29 (2d, 6H, J5,6 = 6.6 Hz, 6.2 Hz,
2 ꢁ C-CH3); 13C NMR (75 MHz, CDCl3) d: 166.5, 165.6, 165.4,
165.1 (4 ꢁ COPh), 155.2 (AllocC), 153.7, 150.1(MpC), 133.3, 133.2,
133.1, 133.0, 131.1(AllocC), 130.0(2), 129.8(4), 129.7(2), 129.6,
129.4, 129.3, 129.2, 128.6(2), 128.4(4), 128.3(2), 119.1 (AllocC),
117.5(2), 114.8(2) (MpC), 98.9, 98.6 (2 ꢁ C-1), 73.4, 72.5, 71.6,
69.5, 69.1 (AllocC), 68.7, 67.8, 67.6, 65.9, 55.7 (C6H4OCH3), 17.5,
16.3 (2 ꢁ C-CH3). Anal. Calcd for C51H48O16: C, 66.80; H, 5.28.
Found: C, 66.62; H, 5.40.
a-
L
a-L
0
0
0
0
Cleavage of the PMP group in 17 (1.4 g, 0.85 mmol) in 5:5:2
CH3CN–THF–H2O (48 mL) and then conversion of the product to
the trichloroacetimidate derivative were accomplished by follow-
ing the same reaction protocol as described above for the prepara-
tion of monosaccharide donor 3. After purification by column
chromatography (petroleum ether–EtOAc 4:1) 18 (0.93 g, 65% over
two steps) was obtained as a white foam. ½a D25
ꢂ
–34 (c 1.0, CHCl3).
1H NMR (300 MHz, CDCl3) d: 8.76 (s, 1H, CNHCCl3), 8.13–7.18 (m,
0
0
45H, BzH), 6.60 (d, 1H, J1,2 = 1.6 Hz, H-1), 5.86 (dd, 1H, J2 ,3 = 3.1 Hz,
J3 ,4 = 10.2 Hz, H-30), 5.78–5.71 (m, 2H, H-3, H-4), 5.59 (t, 1H,
0
0
0
0
0
0
1.10. p-Methoxylphenyl 3,4-di-O-benzoyl-a-L-rhamnopyrano-
J3 ,4 = J4 ,5 = 10.0 Hz, H-40), 5.57 (m, 1H, H-4000), 5.50 (s, 1H, H-1000),
5.48 (t, 1H, J = J
= 4.0 Hz, H-3000), 5.40 (m, 2H, H-200, H-
2000,3000
3000,4000
syl-(1?2)-3,4-di-O-benzoyl- -6-deoxy-talopyranoside (16)
a
-L
400), 5.32 (m, 2H, H-100, H-2000), 4.74 (d, 1H, J1 ,2 = 1.1 Hz, H-10), 4.63
0
0
00 00
00 00
De-O-allyloxycarbonylation of compound 15 (3.2 g, 3.5 mmol)
was accomplished by following the same procedure as described
above for the preparation of compound 9 to afford the disaccharide
(m, 1H, H-5), 4.56 (dd, 1H, J 2 ,3 = J 3 ,4 = 3.8 Hz, H-300), 4.52–4.47
(m, 2H, H-2, H-5), 4.35 (m, 1H, H-5), 4.19 (m, 1H, H-5), 4.11 (m,
1H, H-20), 1.42, 1.37, 1.32, 0.81 (4d, 12H, J5,6 = 6.5 Hz, 4 ꢁ C-CH3).
Anal. Calcd for C89H78Cl3NO26: C, 63.48; H, 4.67; N, 0.83. Found:
C, 63.24; H, 4.96; N, 0.98.
acceptor 16 (2.6 g, 89%) as a foamy solid. ½a D25
ꢂ
+3.5 (c 1.0, CHCl3). 1H
NMR (300 MHz, CDCl3) d: 8.16–7.26 (m, 20H, BzH), 7.13–7.10 (m,
2H, MpH), 6.91–6.88 (m, 2H, MpH), 5.86 (dd, 1H, J2,3 = J3,4 = 3.8 Hz,
H-3), 5.79 (dd, 1H, J2 ,3 = 3.2 Hz, J3 ,4 = 9.9 Hz, H-30), 5.71 (d, 1H,
1.13. p-Methoxylphenyl 2,3,4-tri-O-benzoyl-
pyranosyl-(1?3)-2,4-di-O- benzoyl- -6-deoxy-talopyranosyl-
(1?2)-3,4-di-O-benzoyl- -rhamnopyranoside (19)
a-L-6-deoxy-talo-
0
0
0
0
J1 ,2 = 1.6 Hz, H-10), 5.69 (m, 1H, H-4), 5.55 (t, 1H, J3 ,4 = J4 ,5 = 9.9 Hz,
H-40), 5.21 (d, 1H, J1,2 = 1.6 Hz, H-1), 4.47 (m, 1H, H-5), 4.38 (m, 1H,
H-2), 4.28 (m, 1H, H-50), 4.17 (m, 1H, H-20), 3.80 (s, 3H, C6H4OCH3),
1.31, 1.27 (2d, 6H, J5,6 = 6.6 Hz, 2 ꢁ C–CH3); 13C NMR (75 MHz,
CDCl3): d 166.3, 165.8, 165.4, 165.2 (4 ꢁ COPh), 155.2, 150.1
(MpC), 133.2(3), 133.0, 129.8(2), 129.7(4), 129.6(2), 129.4(4),
128.6(2), 128.5(2), 128.4(4), 117.5(2), 114.8(2) (MpC), 101.1, 98.7
a-L
0
0
0
0
0
0
a-L
Glycosylation between disaccharide acceptor 12 (0.57 g,
0.69 mmol) and monosaccharide donor 7 (0.50 g, 0.81 mmol) was
accomplished by following the same reaction protocol as described
above for the preparation of disaccharide 11. After purification by

2072
G. Zong et al. / Carbohydrate Research 345 (2010) 2067–2073
column chromatography (petroleum ether–toluene–EtOAc 8:3:1)
67.9, 67.8, 67.5, 67.4, 67.0, 66.6, 66.3, 66.1, 66.0, 65.8, 55.7
(C6H4OCH3), 18.0, 17.7, 16.6, 16.2, 16.1(2) (6 ꢁ C-CH3). Anal. Calcd
for C134H120O39: C, 68.36; H, 5.14. Found: C, 68.11; H, 5.32.
19 was obtained as a white solid (0.68 g, 77%). ½a D25
ꢂ
–63 (c 1.0,
CHCl3). 1H NMR (300 MHz, CDCl3) d: 8.11–7.16 (m, 35H, BzH),
7.13-6.88 (m, 4H, MpH), 5.95 (dd, 1H, J2,3 = 3.3 Hz, J3,4 = 10.2 Hz,
H-3), 5.67 (t, 1H, J3,4 = J4,5 = 9.9 Hz, H-4), 5.65–5.58 (m, 5H, H-10,
1.16. p-Methoxylphenyl
6-deoxy talopyranosyl-(1?2)-
6-deoxy-talopyranosyl-(1?3)-
(1?2)- -rhamnopyranoside (III)
a
-
L
-6-deoxy-talopyranosyl-(1?3)-
-rhamnopyranosyl-(1?2)-
-6-deoxy-talopyranosyl-
a-L-
a-L-
H-100, H-20, H-200, H-400), 5.55 (t, 1H, J 2 ,3 = J 3 ,4 = 4.0 Hz, H-300),
5.36 (m, 1H, H-40), 5.30 (d, 1H, J1,2 = 1.1 Hz, H-1), 4.73 (t, 1H,
a
a
-
-L
L
00 00
00 00
J2 ,3 = J3 ,4 = 3.9 Hz, H-30), 4.64–4.24 (m, 4H, H-2, H-5, H-50, H-500),
3.80 (s, 3H, C6H4OCH3), 1.41, 1.33 (2d, 9H, J5,6 = 6.5 Hz, 3 ꢁ C–
CH3); 13C NMR (75 MHz, CDCl3) d: 166.6, 166.3, 166.0, 165.9,
165.6, 165.4, 164.6 (7 ꢁ COPh), 155.3, 150.2(MpC), 133.3, 133.1,
132.9(2), 132.8(2), 132.7, 130.0(6), 129.9(4), 129.8(3), 129.7(2),
129.6(3), 129.5, 129.4, 129.0, 128.5(2), 128.3(4), 128.2(2),
128.1(4), 128.0(2), 117.6(2), 114.8(2) (MpC), 100.6, 97.7, 97.0
(3 ꢁ C-1), 77.2, 77.1, 71.6, 71.0, 69.6, 68.6, 68.5, 68.1, 67.5, 66.5,
66.2, 66.1, 55.6 (C6H4OCH3), 17.7, 16.5, 16.3 (3 ꢁ C-CH3). Anal.
Calcd for C74H66O21: C, 68.83; H, 5.15. Found: C, 68.55; H, 5.34.
a
-L
0
0
0
0
Compound 20 (230 mg, 0.098 mmol) was dissolved in satd
NH3–MeOH (150 ml). After 96 h at rt, the reaction mixture was
concentrated and the residue was purified by chromatography on
Sephadex LH-20 (MeOH) to afford III (79 mg, 81%) as a white solid.
½
a 2D5
ꢂ
ꢀ45 (c 0.5, H2O). 1H NMR (300 MHz, D2O) d: 6.96, 6.85 (2d, 4H,
MpH), 5.34 (s, 1H, H-1), 5.12–5.02 (3s, 5H, 5 ꢁ H-1), 4.13–3.68 (m,
25H), 3.47–3.40 (m, 2H), 1.22, 1.19 (2d, 12H, J5,6 = 6.9 Hz, 4 ꢁ C-
CH3), 1.16, 1.14 (2d, 6H, J5,6 = 5.9 Hz, 2 ꢁ C–CH3); 13C NMR
(75 MHz, D2O) d: 154.9, 149.7, 118.9(2), 115.2(2) (MpC), 102.8,
102.7, 101.4, 98.5, 98.4, 97.3 (6 ꢁ C-1), 72.4, 72.2, 72.1(2), 71.6,
70.9, 70.5, 69.9(2), 69.8, 69.6, 69.5, 69.4, 69.3, 69.2, 69.0, 67.9(2),
67.8(2), 67.6, 65.9, 65.6(2), 55.8 (C6H4OCH3), 16.9, 16.8, 15.7(2),
15.6(2) (6 ꢁ C-CH3). HRMS calcd for C43H68O26Na (M+Na)+:
1023.3896, found: 1023.3875.
1.14. p-Methoxylphenyl
6-deoxy talopyranosyl-(1?2)-
a
-
L
-6-deoxy-talopyranosyl-(1?3)-
-rhamnopyranoside (II)
a-L-
a-L
Trisaccharide 19 (0.41 g, 0.32 mmol) was dissolved in satd
NH3–MeOH (150 mL). After 96 h at rt, the reaction mixture was
concentrated and the residue was purified by chromatography on
Sephadex LH-20 (MeOH) to afford II (0.15 g, 84%) as a white solid.
Acknowledgements
½
a 2D5 –81 (c 0.5, H2O). 1H NMR (300 MHz, D2O) d: 6.96, 6.85 (2d, 4H,
ꢂ
MpH), 5.35, 5.08, 5.05 (3s, 3 ꢁ H-1), 3.41–3.68 (m, 14H, C6H4OCH3),
3.45 (t, 1H, J3,4 = J4,5 = 9.6 Hz, H-4), 1.20, 1.17, 1.14 (3d, 9H,
J5,6 = 6.5 Hz, 3 ꢁ C–CH3); 13C NMR (75 MHz, D2O) d: 154.9, 149.7,
119.0(2), 115.2(2) (ArC), 102.9, 98.6, 98.5 (3 ꢁ C-1), 78.6, 72.4,
72.1, 70.5, 69.9, 69.8, 69.6, 69.4, 69.0, 67.9, 67.8, 65.6, 55.8
(C6H4OCH3), 16.8, 16.7, 15.7 (3 ꢁ C–CH3). HRMS calcd for
This work was supported by the Chinese Universities Scientific
Fund (No. 2009-1-43), the National Basic Research Program of Chi-
na (2010CB126105), NSFC (No. 20902108) of China and the Key
Program of Zhejiang Province (2008C11043).
Supplementary data
C
25H38O14Na (M+Na)+: 585.2159, found: 585.2142.
Supplementary data associated with this article can be found, in
the online version, at doi:10.1016/j.carres.2010.07.023.
1.15. p-Methoxylphenyl 2,3,4-tri-O-benzoyl-
pyranosyl-(1?3)-2,4-di-O- benzoyl- -6-deoxy-talopyranosyl-
(1?2)-3,4-di-O-benzoyl- -rhamnopyranosyl-(1?2)-3,4-di-O-
benzoyl- -6-deoxy-talopyranosyl-(1?3)-2,4-di-O-benzoyl-
-6-deoxy-talopyranosyl-(1?2)-3,4-di-O-benzoyl- -rhamno-
pyranoside (20)
a-L-6-deoxy-talo-
a
-L
a-L
References
a-
L
a-
L
a-L
1. Jarvis, B. D. W.; Van Berkum, P.; Chen, W. X.; Nour, S. M.; Fernandez, M. P.;
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11. Jofre, E.; Lagares, A.; Mori, G. FEMS Microbiol. Lett. 2004, 231, 267–275.
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13. de Maagd, R. A.; Rao, A. S.; Mulders, I. H. M.; Goosen de Roo, L.; van Loosdrecht,
M. C. M.; Wijffelman, C. A.; Lugtenberg, B. J. J. J. Bacteriol. 1989, 171, 1143–1150.
14. Kannenberg, E. L.; Reuhs, B. L.; Forsberg, L. S.; Carlson, R. W. In The
Rhizobiaceae; Spaink, H. P., Kondorosi, A., Hooykaas, P. J. J., Eds.; Kluwer:
Dordrecht, 1998; pp 119–154.
Glycosylation between disaccharide acceptor 12 (0.2 g,
0.24 mmol) and tetrasaccharide donor 18 (0.45 g, 0.27 mmol)
was accomplished by following the same reaction protocol as de-
scribed above for the preparation of disaccharide 11. After purifica-
tion by column chromatography (petroleum ether–EtOAc 3:1) 20
was obtained as a white foam (0.44 g, 79%). ½a D25
ꢂ
–32 (c 1.0, CHCl3).
1H NMR (300 MHz, CDCl3) d: 8.07–7.21 (m, 65H, BzH), 7.15–7.12
(m, 2H, MpH), 6.92–6.89 (m, 2H, MpH), 5.95 (dd, 1H, J2,3 = 3.1 Hz,
J3,4 = 10.0 Hz, H-3 of Rhap), 5.91 (dd, 1H, J2,3 = 3.1 Hz,
J3,4 = 10.0 Hz, H-3 of Rhap), 5.76 (m, 1H, H-20), 5.70 (t, 1H,
J3,4 = J4,5 = 10.0 Hz, H-4 of Rhap), 5.66-5.60 (m, 5H, H-100, H-1000,
3 ꢁ H-4 of Talp), 5.57 (t, 1H, J3,4 = J4,5 = 10.0 Hz, H-4 of Rhap),
5.51–5.47 (m, 3H, H-1, 2 ꢁ H-3 of Talp), 5.41 (m, 1H, H-20000), 5.38
(d, 1H, H-10000), 5.35 (m, 1H, H-40000), 5.30–5.28 (m, 2H, H-1, H-200000),
4.82 (t, 1H, J2 ,3 = J3 ,4 = 3.8 Hz, H-30), 4.71 (m, 1H, H-5), 4.58–4.52
(m, 5H, H-1000, H-200, H-30000, 2 ꢁ H-5), 4.40–4.21 (m, 3H, 3 ꢁ H-5),
4.04, 4.01 (2 m, 2H, 2 ꢁ H-2), 3.80 (s, 3H, C6H4OCH3), 1.53, 1.47,
1.35, 1.33, 1.32, 0.77 (6d, 18H, J5,6 = 6.5 Hz, 6 ꢁ C–CH3); 13C NMR
(75 MHz, CDCl3) d: 166.5(2), 166.4, 166.3, 165.9(2), 165.8, 165.6,
165.5, 165.5, 165.3, 165.2, 164.6 (13 ꢁ COPh), 155.3, 150.3 (MpC),
133.4, 133.2(2), 133.1, 132.9(3), 132.8(5), 132.7, 130.1(3),
130.0(8), 129.9(10), 129.8(8), 129.7(4), 129.6(4), 129.4, 129.0,
128.5(6), 128.3(4), 128.2(7), 128.1(3), 128.0(6), 117.6(2), 114.8(2)
(MpC), 100.8, 100.1, 98.6, 97.7, 97.3, 96.8 (6 ꢁ C-1), 78.4, 77.3,
72.0, 71.5, 71.1, 70.9, 70.6, 69.8, 69.6, 68.8, 68.6, 68.4, 68.2, 68.1,
0
0
0
0
15. Learemans, T.; Vanderleyden, J. World J. Microbiol. Biotechnol. 1998, 14, 787–
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