Synthesis of the α-L-Araf-(1 → 2)-β-D-Galp-(1 → 6)-β-D-Galp-(1 → 6)-[α-L-Araf-(1 → 2)]-β-D-Galp-(1 → 6)-D-Gal hexasaccharide as a possible repeating unit of the cell-cultured exudates of Echinacea purpurea arabinogalactan

Article abstract of DOI:10.1016/S0008-6215(01)00232-4

For the characterization of the supposed epitope of an arabinogalactan, isolated from the extract of the cell-cultured Echinacea purpurea, the title hexasaccharide was synthesized. The whole synthetic route was based on the 6-O-(methoxydimethyl)methyl ether (MIP) protecting group strategy. 2-O-Benzyl-3,4-O-isopropylidene-6-O-(methoxydimethyl)methyl-β-D- galactopyranosyl-(1 → 6)-1,2:3,4-di-O-isopropylidene-α-D-galactopyranose was used to prepare the desired glycosyl donor and glycosyl acceptor both carrying a persistent O-benzyl group at position 2′. Reaction of the digalactose donor and the digalactose acceptor resulted in a β-(1 → 6)-linked galactose-containing tetrasaccharide in which OH-2′ and OH-2? were substituted with benzyl groups. Hydrogenolytic removal of the benzyl groups of the tetragalactose compound gave the diol aglycon which was diarabinosylated in one step to furnish the protected target compound, whose deprotection led to the title hexasaccharide. All of the synthesized compounds were characterized by ¹H and ¹³C NMR spectra, as well as by MALDI-TOF mass-spectrometry measurements.

Full text of DOI:10.1016/S0008-6215(01)00232-4

www.elsevier.com/locate/carres
Carbohydrate Research 336 (2001) 107–115
Synthesis of the
a-
L
-Araf-(1“2)-b-
D
-Galp-(1“6)-b-
D
-Galp-(1“6)-
[a-
L
-Araf-(1“2)]-b-
D-Galp-(1“6)- -Gal hexasaccharide
D
as a possible repeating unit of the cell-cultured exudates
of Echinacea purpurea arabinogalactan
Magdolna Csa´va´s,a Aniko´ Borba´s,a Lo´ra´nt Ja´nossy,b Gyula Batta,c Andra´s Lipta´ka,b,*
aResearch Group for Carbohydrates of the Hungarian Academy of Sciences, PO Box 70,
H-4010 Debrecen, Hungary
bDepartment of Biochemistry, Faculty of Sciences, Uni6ersity of Debrecen, PO Box 55, H-4010 Debrecen, Hungary
cResearch Group of Antibiotics of the Hungarian Academy of Sciences, PO Box 70, H-4010 Debrecen, Hungary
Received 4 May 2001; accepted 13 August 2001
Dedicated to Professor Joachim Thiem on the occasion of his 60th birthday
Abstract
For the characterization of the supposed epitope of an arabinogalactan, isolated from the extract of the
cell-cultured Echinacea purpurea, the title hexasaccharide was synthesized. The whole synthetic route was based on
the 6-O-(methoxydimethyl)methyl ether (MIP) protecting group strategy. 2-O-Benzyl-3,4-O-isopropylidene-6-O-
(methoxydimethyl)methyl-b-
D
-galactopyranosyl-(1“6)-1,2:3,4-di-O-isopropylidene-a-D-galactopyranose was used to
prepare the desired glycosyl donor and glycosyl acceptor both carrying a persistent O-benzyl group at position 2%.
Reaction of the digalactose donor and the digalactose acceptor resulted in a b-(1“6)-linked galactose-containing
tetrasaccharide in which OH-2% and OH-2%%% were substituted with benzyl groups. Hydrogenolytic removal of the
benzyl groups of the tetragalactose compound gave the diol aglycon which was diarabinosylated in one step to
furnish the protected target compound, whose deprotection led to the title hexasaccharide. All of the synthesized
compounds were characterized by 1H and 13C NMR spectra, as well as by MALDI-TOF mass-spectrometry
measurements. © 2001 Elsevier Science Ltd. All rights reserved.
Keywords: Echinacea purpurea; Arabinogalactans; MIP ethers; Branched-hexasaccharide
distributed representatives in nature. Their
biological functions are unknown, although
the maple syrup of Acer pseudoplatanus,1 the
roots of Angelica acutiloba and Bupleurum
falcatum are applied in folk-medicine for cur-
ing different diseases.2,3 Similarly, the extract
of the cell-cultured Echinacea purpurea4,5
shows promising biological activity, and all of
1. Introduction
Among the plant tissue glycoproteins the
arabinogalactan-proteins are the most widely
* Corresponding author. Tel.: +36-52-512900x2256; fax:
+36-52-512913.
E-mail address: liptaka@tigris.kltelhu (A. Lipta´k).
0008-6215/01/$ - see front matter © 2001 Elsevier Science Ltd. All rights reserved.
PII: S0008-6215(01)00232-4

108
M. Csa´6a´s et al. / Carbohydrate Research 336 (2001) 107–115
these effects are attributed to the arabino-
galactan components of the extracts. The ex-
act structure of these polysaccharides are
unknown, although monoclonal antibodies di-
rected against epitopes of the polysaccharides
can provide useful and fast structural informa-
tion. In all of the above cases a b-(1“6)-
linked galactan skeleton was anticipated to be
present, and each third or fourth galactopy-
(1“6)-1,2:3,4-di-O-isopropylidene-a- -galac-
D
topyranose.8 Compound 2 carries three persis-
tent dioxolane-type blocking groups, one tem-
porary 6%-O-(methoxydimethyl)methyl (MIP)
function, and a free OH-2% which is ready for
further transformation. The only drawback of
the application of compound 2 is that the MIP
group is rather sensitive under the generally
used glycosylation conditions, due to hydroly-
sis or its participation in condensation
reactions.8
ranoside unit was thought to be a- -arabino-
L
furanosylated at C-2. To obtain structurally
well defined epitopes for further characteriza-
tion of the monoclonal antibodies, three
groups of researchers synthesized the follow-
This difficulty was solved by avoiding the
direct glycosylation of the MIP-protected dis-
accharide. Namely, our former synthetic strat-
egy had been arabinosylation of compound 2
at position OH-2%, then, after splitting of the
6%-OMIP group, chain elongation of the b-
(1“6)-galactan skeleton. Since our experi-
ments showed either the sensitivity or
reactivity of MIP-group under glycosylation
conditions we have changed our strategy. First
we elongated the galactan skeleton, and then
formed the arabinosyl branches. For the
preparation of building blocks, suitable for
the synthesis of a tetragalactan chain, OH-2%
of compound 2 was benzylated to give 3. The
disaccharide 3 is useful for the preparation
both of the glycosyl donor and the glycosyl
acceptor in the synthesis of the target tetra-
saccharide (8). Complete acid hydrolysis of
the acetal groups of 3 resulted in a monoben-
zyl digalactoside, which was directly acetyl-
ated to obtain compound 48 as an anomeric
mixture (of pyranoses and furanoses) at the
reducing end. The ratio of the four isomers
(a-, b-pyranose and a-, b-furanose) was
ꢀ80:10:5:5.
ing model oligosaccharides: a-
b- -Galp-(1“6)-b- -Galp-(1“6)-b-
(1“OMCUD),6 b-
(1“2)]-b- -Galp-(1“6)-b-
-Galp-(1“6)-b-
L
-Araf-(1“2)-
D
D
D
-Galp-
D
-Galp-(1“6)-[a-
L
-Araf-
D
D
-Galp-(1“OM-
CUD),6 b-
-Araf-(1“2)]-b-
D
D
-Galp-(1“6)-[a-
L
D
-Galp-(1“OMCUD),6 b-
-Galp-(1“6)-[a- -Araf-
-Galp-(1“ODD),7 a-
-Araf-(1“
-Araf-(1“6)-
-Araf )2-(1“
-Gal,8 where MCUD
D
-Galp-(1“6)-b-
D
L
(1“2)]-b-
2)-b-
b-
2,6)-b-
D
L
D
-Galp-(1“6)-
D
-Gal,8 a-
-Gal,8
(a-
L
D
-Galp-(1“6)-
D
L
D
-Galp-(1“6)-
D
and DD are 11-methoxycarbonylundecanyl
and dodecyl spacers.
These target compounds are structurally
very similar, but the synthetic approaches
used are completely different.6–8
2. Results and discussion
Our synthetic goal was to prepare the hex-
asaccharide 1, a-
(1“6)-b- -Galp-(1“6)-[a-
-Galp-(1“6)- -Gal, which is the anticipated
L
-Araf-(1“2)-b-
D
-Galp-
D
L
-Araf-(1“2)]-b-
The isolated pure 3,4,6-tri-O-acetyl-2-O-
D
D
benzyl-b-
D
-galactopyranosyl-(1“6)-1,2,3,4-
repeating unit and may be the epitope of the
arabinogalactan isolated from the industrial
scale cell culture of E. purpurea. Our key
tetra-O-acetyl-a-
D
-galactopyranose (4) was
characterized by its 13C NMR spectrum and
selectively deacetylated at the anomeric posi-
tion with hydrazine acetate to obtain the OH-
1 compound (5) which was transformed
without characterization into the b-tri-
chloroacetimidoyl derivative (6) using K2CO3
as the base and trichloroacetonitrile as the
reagent10 and compound 3 was converted to
glycosyl acceptor 78 (Scheme 1).
reaction was the treatment of a free b- -
D
galactopyranosyl unit with 2,2-dimethoxy-
propane in the presence of an acid catalyst to
obtain 3,4-O-isopropylidene-6-O-(methoxy-
dimethyl)methyl-b- -galactopyranoside build-
D
ing blocks.9 This reaction was developed in
1983,8 and it was successfully employed for
the preparation of the key disaccharide 2
starting either from galactopyranosyl-(1“6)-
Trimethylsilyl triflate-promoted glycosyla-
tion of 7 with 6 proceeded with an excellent
yield. The obtained tetrasaccharide (8) was
D
-galactose or from b- -galactopyranosyl-
D

M. Csa´6a´s et al. / Carbohydrate Research 336 (2001) 107–115
109
characterized by the NMR spectra and
MALDI-TOF mass-spectrometry. Having the
tetrasaccharide 8 in hand, the removal of the
two benzyl groups was attempted. To avoid
acetyl migration at the terminal galactopyran-
oside (OH-2%%%) we used ethyl acetate as the
solvent and Pd-on-carbon as the catalyst.
These reaction conditions proved to be suc-
cessful; after 14 h the reduction was complete
and in compound 9 no acetyl migration could
be detected either by chromatographic or by
spectroscopic methods (Scheme 2).
The isolated diol 9 was used as the aglycone
and glycosylation was achieved with the
known 2,3,5-tri-O-benzoyl-a-
L
-arabinofuran-
osyl bromide (10)11 in acetonitrile, in the
Scheme 1. Synthesis of the disaccharide-type glycosyl donor (6) and glycosyl acceptor (7) from the same building block (3).
Scheme 2. Synthesis of the tetrasaccharide diol (9) through compound 8.

110
M. Csa´6a´s et al. / Carbohydrate Research 336 (2001) 107–115
1
Fig. 1. 1D H NMR spectrum of the fully protected hexasaccharide 11. The spectrum was acquired at 320 K and 500 MHz in
CDCl3.
Scheme 3. Structure of the fully protected hexasaccharide (11) and the free hexasaccharide (1).
Deprotection of compound 11 required a
strict sequence of reactions; first the isopropy-
lidene groups were hydrolyzed with trifl-
uoroacetic acid in dichloromethane in the
presence of a very small amount of water, then
the product was deacylated by Zemple´n. Pure
1 was then obtained after chromatographic
purification in a yield of 88% (Scheme 3).
presence of Hg(CN)2 promoter to give the
fully protected hexasaccharide (11). Com-
1
pound 11 showed well-resolved H and 13C
NMR spectra at 500 and 125 MHz (Fig. 1).
The COSY, HETCOR and HMBC spectra
allowed a complete assignment, and MALDI-
TOF-MS also verified the hexasaccharide
structure.

M. Csa´6a´s et al. / Carbohydrate Research 336 (2001) 107–115
111
1
The H (Fig. 2) and 13C NMR (Fig. 3)
are uncorrected. TLC was performed on
Kieselgel 60 F254 (E. Merck) with detection by
charring with 50% aq H2SO4. Column chro-
matography was performed on Silica Gel 60
(E. Merck, 0.062–0.200 nm). The organic so-
lutions were dried over MgSO4, and concen-
spectra of compound 1 were extremely over-
crowded, and complete assignment could not
be achieved even at 500 (125) MHz fields.
Fortunately, the signals of the anomeric re-
gion of both spectra were quite well separated
and complete assignment could be achieved in
this region. Also, the JH1,H2 and JC1,H1 values
were measured and these data unequivocally
confirmed the declared structure of the hexas-
accharide 1, which was also substantiated by
MALDI-TOF MS, using dihydroxybenzoic
acid (DHB) as a matrix. The NMR data are
collected in Tables 1 and 2.
1
trated in a vacuum. The H (200, 360 and 500
3
1
MHz) and 13C NMR (50.3, 90.54, 125.76
MHz) spectra were recorded with Bruker WP-
200SY, Bruker AM-360 and Bruker DRX-500
spectrometers in CDCl3 or in D2O solutions.
1
Internal references: TMS (0.00 ppm for H),
CDCl3 (77.00 ppm for 13C).
MALDI-TOF MS analysis of the com-
pounds was carried out in the positive reflec-
tron mode using BIFLEX III mass
spectrometer (Bruker, Germany) equipped
with delayed-ion extraction. Spectra from
multiple (at least 100) laser shots (N2 laser,
337 nm) were summarized using 19 kV accel-
erating and 20 kV reflectron voltage. The
compounds were identified as [M+Na]+
3. Experimental
General methods.—Optical rotations were
measured at rt with a Perkin–Elmer 241 auto-
matic polarimeter. Melting points were deter-
mined on a Kofler hot-stage apparatus and
1
Fig. 2. 1D H NMR spectrum of the free hexasaccharide 1. The spectrum was acquired at 320 K and 500 MHz in D2O.

112
M. Csa´6a´s et al. / Carbohydrate Research 336 (2001) 107–115
1
Fig. 3. 2D H–13C correlated NMR spectrum of the free hexasaccharide 1. The spectrum was acquired at 298 K, 500/125 MHz
in D2O.
peaks using a 2,5-dihydroxybenzoic acid
(DHB) matrix.
3,4,6-Tri-O-acetyl-2-O-benzyl-i-
pyranosyl - (1“6) - 2,3,4 - tri - O - acetyl - i -
galactopyranosyl-(1“6)-2-O-benzyl-3,4-O-
isopropylidene-i- -galactopyranosyl-(1“6)-
D
-galacto-
D
-
3,4,6-Tri-O-acetyl-2-O-benzyl-i-
D
-galacto-
pyranosyl - (1“6) - 2,3,4 - tri - O - acetyl - i -
D
-
D
galactopyranosyl trichloroacetimidate (6).—To
a solution of 48 (508 mg, 0.79 mmol) in dry
N,N-DMF (1 mL) was added 97 mg of hydra-
zine acetate and the mixture was stirred for
1.5 h, until TLC showed a complete conver-
sion (92:8, CH2Cl2 –acetone, Rf 0.75). The
mixture was diluted with 50 mL of CH2Cl2,
washed twice with aq 10% NaCl and three
times with water, dried over MgSO4 and con-
centrated. The residue was purified by means
of column chromatography (87:13, CH2Cl2–
acetone) to yield 5 (235 mg, 50%). To a solu-
tion of 5 (235 mg, 0.33 mmol) in dry CH2Cl2
was added CCl3CN (0.46 mL) and heated with
K2CO3 (500 mg). Complete conversion was
observed after 24 h (TLC: 92:8, CH2Cl2 –ace-
tone). The mixture was filtered through a pad
of Celite, concentrated, and the product was
purified by column chromatography (92:8,
CH2Cl2–acetone) to yield 6 (197 mg, 70%);
[h]D +18.36° (c 0.41, CHCl3); Anal. Calcd for
C33H40Cl3NO17 (827.14): C, 47.87; H, 4.87.
Found: C, 47.93; H, 4.88.
1,2:3,4-di-O-isopropylidene-h- -galactopyran-
D
ose (8).—To a solution of 78 (235 mg, 0.43
mmol) in dry CH2Cl2 (10 mL) were added
compound 6 (0.43 g, 0.51 mmol, 1.2 equiv.)
,
and 4 A molecular sieves (600 mg), and the
mixture was stirred for 1 h at rt. It was then
cooled to −45 °C, and trimethylsilyl trifl-
uormethanesulfonate (15 mL in 0.5 mL of dry
CH2Cl2) was added. After 2 h 100 mL of
triethylamine was added, the mixture was di-
luted with 40 mL of CH2Cl2, washed with
water, dried, and concentrated. The crude
product was purified by column chromatogra-
phy (88:12, CH2Cl2–acetone) to give 8 (320
mg, 60%). [h]D −1.63° (c 0.97, CHCl3); Anal.
Calcd for C59H78O27 (1218.47): C, 58.11; H,
6.45. Found: C, 58.30; H, 6.44.
3,4,6-Tri-O-acetyl-i-
(1“6)-2,3,4-tri-O-acetyl-i-
syl-(1“6)-3,4-O-isopropylidene-i-
pyranosyl-(1“6)-1,2:3,4-di-O-isopropylidene-
h- -galactopyranose (9).—Palladium on acti-
vated charcoal (100 mg) was added to a solu-
D
-galactopyranosyl-
-galactopyrano-
-galacto-
D
D
D

M. Csa´6a´s et al. / Carbohydrate Research 336 (2001) 107–115
113
tion of 8 (500 mg, 0.4 mmol) in EtOAc (5
mL). After hydrogenation for 12 h the mix-
ture was diluted with EtOAc, filtered through
a layer of Celite and concentrated. The
product was purified by column chroma-
tography (7:3, CH2Cl2–acetone) to obtain
9 (308 mg, 89%); [h]D −22.37° (c 0.22,
CHCl3). Anal. Calcd for C45H66O27 (1038.38):
C, 51.98; H, 6.40. Found: C, 52.06; H,
6.39.
2,3,5-Tri-O-benzoyl-h-
(1“2)-3,4,6-tri-O-acetyl-i-
syl-(1“6)-2,3,4-tri-O-acetyl-i-
ranosyl-(1“6)-[2,3,5-tri-O-benzoyl-h-
binofuranosyl-(1“2)]-3,4-O-isopropylidene-i-
-galactopyranosyl-(1“6)-1,2:3,4-di-O-iso-
L
-arabinofuranosyl-
-galactopyrano-
-galactopy-
-ara-
D
D
L
D
Table 1
3
1H NMR chemical shift- and JH1,H2 coupling constant values for compounds 1 and 11
Sugar ring
Carbon
l (ppm)
3JH1,H2
11
1
11
1
a
b
a
b
1
2
3
4
5
6
6%
1
2
3
4
5
6
6%
1
2
3
4
5
5%
1
2
3
4
5
6
6%
1
2
3
4
5
6
6%
1
2
3
4
5
5%
5.207
4.113
4.477
4.171
3.960
4.201
3.567
4.359
3.940
4.738
4.078
3.931
4.048
3.780
5.679
5.066
5.647
5.582
4.895
4.825
4.647
5.093
5.210
5.380
3.900
3.819
3.682
4.509
3.940
5.031
5.474
3.989
4.130
5.44
3.99
4.75
3.68
J1,2
J2,3
J3,4
J4,5
J5,6
J6,6%
4.91
7.88
2.36
7.87
2.0
3.7
8.0
A
10.4
4.702
3.835
4.163
J1,2
J2,3
J3,4
J4,5
J5,6
J6,6%
8.2
10.5
4.8
10.3
6.1
7.5
B
C
10.3
5.48
4.37
4.14
4.34
3.9
J1,2
J2,3
J3,4
J4,5
J5,5%
\1
3.5
3.4
\1
12.0
B3
4.63
3.73
J1,2
J2,3
J3,4
J4,5
J5,6
J6,6%
8.0
9.5
3.6
3.6
2.0
7.5
D
10.4
4.74
3.818
4.163
J1,2
J2,3
J3,4
J4,5
J5,6
J6,6%
7.7
10.4
3.4
3.6
1.8
7.5
E
F
9.3
5.495
5.066
5.647
5.415
4.823
4.710
5.48
4.37
4.14
4.38
3.92
J1,2
J2,3
J3,4
J4,5
J5,5%
\1
3.4
1.4
1.6
12.1
B3

114
M. Csa´6a´s et al. / Carbohydrate Research 336 (2001) 107–115
Table 2
1
13C NMR chemical shift- and JC1,H1 coupling constant values for compounds 1, 8, 9, and 11
Sugar ring
Carbon
l (ppm)
1JC1,H1 (Hz)
8
9
11
1
1
a
b
a
b
1
2
3
4
5
6
1
2
3
4
5
6
1
2
3
4
5
1
2
3
4
5
6
1
2
3
4
5
6
1
2
3
4
5
96.27
70.65
70.90
70.35
67.52
68.91
103.27
78.01
78.66
73.66
72.65
69.51
96.15
70.60
70.85
70.29
67.35
68.90
103.05
71.04
78.81
73.61
72.31
69.12
96.77
93.05
73.55
97.09
72.56
170.2
161.4
70.66
71.52
72.27
67.96
70.36
102.01
75.40
81.65
74.63
72.85
69.70
104.65
81.65
78.41
83.14
64.20
102.01
71.60
69.63
67.96
70.36
67.28
102.52
75.40
73.57
68.32
73.15
62.02
106.72
81.15
78.41
82.91
64.28
A
102.72
73.32
69.51
161
B
C
108.91
81.64
77.54
85.21
61.89
103.88
71.44
176
161
101.27
71.88
68.75
67.28
70.66
67.05
103.53
75.98
72.97
68.91
73.66
61.22
101.22
71.85
68.69
66.77
70.70
67.04
103.17
67.87
73.03
68.90
73.15
61.31
D
102.72
76.78
69.51
161
176
E
F
108.91
81.64
77.54
85.04
62.07
and washed with aq 5% KI solution (4×25
mL) and water (2×25 mL). The organic layer
was dried and concentrated. The syrupy
residue was purified by column chromatogra-
phy (93:7, CH2Cl2–acetone) to yield 11 (340
mg, 62.5%). [h]D −7.36° (c 0.063, CHCl3).
MALDI-TOF MS: m/z 1949.33 [M+Na]+,
([C97H106O41+Na]+ Calcd 1949.62), resolu-
propylidene-h- -galactopyranose (11).—Pow-
D
dered Hg(CN)2 (162 mg, 0.64 mmol, 2.2
,
equiv.) and 4 A molecular sieves were added
to a solution of 9 (308 mg, 0.29 mmol) in dry
CH3CN (7 mL), the mixture was stirred for
3 h, and compound 1011 (0.748 g, 1.45 mmol,
5 equiv.) was added to the mixture. After 2 h
TLC (9:1, CH2Cl2–acetone) showed a com-
plete conversion. The mixture was diluted
with CH2Cl2, the inorganic salts were filtered
off, and the filtrate was concentrated. The
residue was dissolved in 150 mL of CH2Cl2
1
tion 2700. H and 13C NMR data see in
Table 1.
h-
L
-Arabinofuranosyl-(1“2)-i-
D
-galacto-
pyranosyl-(1“6)-i-
D
-galactopyranosyl-(1“6)

M. Csa´6a´s et al. / Carbohydrate Research 336 (2001) 107–115
115
Acknowledgements
-[h-
L
-arabinofuranosyl-(1“2)]-i-
D
-galacto-
pyranosyl-(1“6)-h,i-
D
-galactose (1). —To a
This research was supported by the Hun-
garian Scientific Research Fund (OTKA
T025244) and the Hungarian Academy of Sci-
ences (AKP 2000-162 2,4).
stirred solution of 11 (220 mg, 0.114 mmol) in
25 mL of CH2Cl2, 3.8 mL of trifluoroacetic
acid and one drop of water were added. After
24 h triethylamine was added, the mixture was
diluted with 75 mL of CH2Cl2, washed with
aq NaHCO3 solution (4×15 mL), and water
(2×15 mL), dried and evaporated. To a
stirred solution of the residue (180 mg) in dry
MeOH (10 mL) was added NaOMe (pH ꢀ8).
After 12 h TLC (50:50:28, acetone–EtOH–
water) showed a complete conversion. The
solution was neutralized with Amberlite IR-
120 H+ ion-exchange resin, filtered and con-
centrated. The residue was dissolved in water
(50 mL), washed with Et2O (3×10 mL) and
concentrated. The residue was purified by
column chromatography (50:50:28, acetone–
ethanol–water) to give 1 (94 mg, 88%); [h]D
−31.43° (c 0.14, water). Characteristic 13C
NMR data: 92.8 (C-1a), 96.8 (C-1b), 102.5
(C-1% and C-1%%%), 103.7 (C-1%%); 108.8 (C-1s
of the Araf units). MALDI-TOF MS: m/z
953.34 [M+Na]+, ([C34H58O29+Na]+ Calcd
953.30), resolution 3900.
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