An Efficient Method for the Synthesis of 2,6-Branched Galacto- Oligosaccharides and Its Applications to the Synthesis of Three Tetrasaccharides and a Hexasaccharide Related to the Arabinogalactans (AGs)

Article abstract of DOI:10.1055/s-2003-42109

An efficient method for the synthesis of 2,6-branched galacto- oligosaccharides has been developed by using 6-O-Ac-2,3,4-tri-O-Bz-α-D- galactopyranosyl trichloroacetimidate, 2,6-di-O-Ac-3,4-di-O-Bz-α-D- galactopyranosyl trichloroacetimidate and 2-O-Ac-3,4,6-tri-O-Bz-α-D- galactopyranosyl trichloroacetimidate as synthons. Three tetrasaccharides and a hexasaccharides related to AGs from plants were readily prepared using this method.

Full text of DOI:10.1055/s-2003-42109

2208
LETTER
An Efficient Method for the Synthesis of 2,6-Branched Galacto-Oligo-
saccharides and Its Applications to the Synthesis of Three Tetrasaccharides
and a Hexasaccharide Related to the Arabinogalactans (AGs)
Synthesis
uof 2,6-Branc
n
hed
G
alacto-Oligo
N
Research Center for Eco-Environmental Sciences, Academia Sinica, P. O. Box 2871, Beijing 100085, P. R. China
Fax +86(10)62923563; E-mail: jning@mail.rcees.ac.cn
Received 15 September 2003
the construction of 3,6-branched gluco-oligosaccharides,2
Abstract: An efficient method for the synthesis of 2,6-branched ga-
lacto-oligosaccharides has been developed by using 6-O-Ac-2,3,4-
tri-O-Bz-a-D-galactopyranosyl trichloroacetimidate, 2,6-di-O-Ac-
3,4-di-O-Bz-a-D-galactopyranosyl trichloroacetimidate and 2-O-
Ac-3,4,6-tri-O-Bz-a-D-galactopyranosyl trichloroacetimidate as
synthons. Three tetrasaccharides and a hexasaccharides related to
AGs from plants were readily prepared using this method.
2,6-branched manno-oligosaccharides,3 3,6-branched and
5,6-branched galacto-oligosaccharides.4,5
2,6-Branched D-Galp residues like 2-O-arabinofurano-
sylated-b-D-(1→6)-linked galacto-oligosaccharides are
common structural components of AGs from plants in-
cluding traditional herbal medicines such as Acer pseudo-
platanus,6 Angelica acutiloba and Bupleurum falcatum.7
Researches shown that the pharmacological activities of
these herbal plants are mainly attributed to AGs. So far,
the presence of 2,6-branched b-D-Galp residues in AGs is
well defined, however, the exact structure of these saccha-
rides remains to be established. For detailed characteriza-
tion of AGs, especially, for further elucidation of the
molecular structure responsible for their biological activ-
ity, it would be necessary to synthesize 2,6-branched ga-
lacto-oligosaccharides. Several methods for preparation
of 2,6-branched galacto-oligosaccharides have been de-
scribed in literatures.8 Here we disclose an efficient strat-
egy for synthesis of this kind of oligosaccharides.
Constructions of three tetrasaccharides and a hexasaccha-
ride related to AGs from plants have been presented as
typical examples using the method developed (Figure 1).
Key words: arabinogalactan, oligosaccharides, synthesis, glyco-
sides, glycosylations
Increased appreciation of the role of carbohydrates in the
biological and pharmaceutical science resulted in a reviv-
al of interest in carbohydrate chemistry. However, com-
pared with other biopolymers such as peptides and nucleic
acids, the role of saccharide structure in function has been
minimally studied. This can be attributed mainly to the
difficulty of synthesizing saccharides. Unlike peptides
and nucleic acids, oligosaccharides are typically branched
rather than linear. In addition, the monosaccharide units
can be connected by a or b linkages. Furthermore, oli-
gosaccharide synthesis requires multiple selective protec-
tion and deprotection steps. Although over the past few
decades, considerable progress has been made in this
field,1 there still is no general solution for oligosaccharide
synthesis. Maybe, owing to this structural complexity, the
preparation of saccharides will never achieve the same
level of ease as the preparation of peptides and nucleic ac-
ids, but we can create relatively general procedures which
are effective for certain types of oligosaccharide. As our
continuous efforts dedicated to the synthesis of oligosac-
charides, we have developed highly efficient strategies for
In our synthesis, 6-O-Ac-2,3,4-tri-O-Bz-a-D-galactopyra-
nosyl trichloroacetimidate (8), 2-O-Ac-3,4,6-tri-O-Bz-a-
D-galactopyranosyl trichloroacetimidate (13) and 2,6-di-
O-Ac-3,4-di-O-Bz-a-D-galactopyranosyl trichloroace-
timidate (17) were the key synthons. Tritylation of galac-
tose (5) followed by benzoylation in a one-pot manner
gave 1,2,3,4-tetra-O-Bz-6-O-Tr-D-galactoyranose, selec-
tive acetolysis of which using CH2Cl2–AcOH–Ac2O–
Figure 1
SYNLETT 2003, No. 14, pp 2208–2212
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6
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1
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0
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3
Advanced online publication: 29.10.2003
DOI: 10.1055/s-2003-42109; Art ID: U13303ST
© Georg Thieme Verlag Stuttgart · New York

LETTER
Synthesis of 2,6-Branched Galacto-Oligosaccharides
2209
H2SO4 in a ratio of 1:1:0.6:0.175 afforded the correspond- molecular sieves in CH2Cl2 at –45 °C regio- and stereo-
ing 1,6-diacetate 6 in 70% yield (for three steps). The di- specifically afforded the trisaccharides 22 in 82% yield.
1
acetate 6 was selectively deacetylated at the anomeric No (1→2)-linked trisaccharide was detected from H
position with benzylamine in THF in high yield to give the NMR and TLC. Condensation of 22 with 2,3,5-tri-O-Bz-
corresponding 6-O-Ac-2,3,4-tri-O-Bz-D-galactopyranose a-L-arabinofuranosyl trichloroacetimidate4 afforded the
(7). Subsequent reaction of 7 with CCl3CN/DBU in tetrasaccharide block 23 in 84% yield. Coupling of com-
CH2Cl2 afforded the glycosyl donor 8 (Scheme 1). Ben- pound 8 with the glycosyl acceptor 19 followed by 6-O-
zoylation of 1,2-O-ethylidene-a-D-galactopyranose9 (9) deacetylation gave the disaccharide glycosyl acceptor 25
followed by hydrolysis with 90% CF3COOH afforded in 87% yield. The trisaccharide glycosyl acceptor 27 was
3,4,6-tri-O-Bz-D-galactopyranose (10), subsequent acety- obtained from condensation of 25 and 13 followed by 2-
lation with Ac2O in pyridine furnished the diacetate 11. O-deacetylation in 72% yield. Condensation of 27 with
Selective 1-O-deacetylation of 11 and then treatment with 2,3,5-tri-O-Bz-a-L-arabinofuranosyl trichloroacetimidate
CCl3CN/DBU in CH2Cl2 afforded the glycosyl donor 13 afforded the tetrasaccharide block 28 in 85% yield.
(Scheme 2). Tritylation of 1,2-O-ethylidene-b-D-galacto- Deprotection of 23 and 28 using NH3 in CH3OH gave the
pyranose (9) followed by benzoylation in a one-pot man- free tetrasaccharides 1 and 2 as amorphous white solids in
ner gave the 3,4-di-O-Bz-6-O-Tr-1,2-O-ethylidene-D- high yields.
galactopyranose (14) (Scheme 3). Acetolysis of 14 af-
The glycosyl acceptor 30 was obtained from coupling of
forded
1,2,6-tri-O-Ac-3,4-di-O-Bz-D-galactopyranose
compound 17 with dodecyl alcohol followed by 2,6-di-O-
deacetylation with MeOH solution containing 0.5% HCl
in 76% yield for two steps (Scheme 5). Coupling of 30
with 8 using TMSOTf as catalyst and 4Å molecular sieves
in CH2Cl2 at –45 °C regio- and stereospecifically afforded
the disaccharide 31 in 84% yield. Condensation of 31 with
(15). The triacetate 15 was selectively deacetylated at the
anomeric position with benzylamine in THF in high yield
to give the corresponding 2,6-di-O-Ac-3,4-di-O-Bz-D-ga-
lactoyranose (16). Subsequent reaction of 16 with
CCl3CN/DBU in CH2Cl2 afforded the glycosyl donor 17.
Coupling of 8 with dodecyl alcohol followed by selective 2,3,5-tri-O-Bz-a-L-arabinofuranosyl trichloroacetimidate
6-O-deacetylation in MeOH solution containing 0.5% afforded the trisaccharide 32 in 85% yield. Selective re-
HCl gave the glycosyl acceptor 19 in 87% yield for two moval of the 6-O-acetyl group of the trisaccharide 32 gave
steps.3 The disaccharide glycosyl acceptor 21 was ob- the glycosyl acceptor 33 in 93% yield. Coupling of 17
tained from condensation of 17 and 19 followed by 2,6- with 33 gave the tetrasaccharide 34. Selective removal of
di-O-deacetylation in 71% yield (Scheme 4). Coupling the acetyl group of 34 gave the glycosyl acceptor 35 in
of 21 with 2,3,4,6-tetra-O-Bz-a-D-galactopyranosyl tri- 94% yield. Coupling of 35 with 2,3,4,6-tetra-O-Bz-a-D-
chloroacetimidate10 using TMSOTf as catalyst and 4 Å galactopyranosyl trichloroacetimidate regio- and stereo-
Scheme 1 Reagents and conditions: (a) i. Trityl chloride (1.2 equiv), pyridine, 50 °C, 32 h; ii. PhCOCl (4.8 equiv), < 40 °C, 24 h; iii. CH2Cl2–
HOAc–Ac2O–H2SO4 = 1:1:0.6:0.175 (v/v), r.t., 20 h, 70% (for three steps). (b) Benzylamine (3.2 equiv.), THF, r.t., 24 h, 85%. (c) CCl3CN (2.3
equiv), DBU (0.18 equiv), CH2Cl2, r.t., 5 h, 84%.
Scheme 2 Reagents and conditions: (a) i. PhCOCl (3.3 equiv), pyridine, <40 °C, 24 h, 95%; ii. F3CCOOH (90%), r.t., 4 h, 89%. (b) Ac2O,
pyridine, r.t., 5 h, 100%. (c) Benzylamine (4.0 equiv), THF, r.t., 24 h, 88%. (d) CCl3CN (3.3 equiv), DBU (0.3 equiv), CH2Cl2, r.t., 5 h, 86%.
Scheme 3 Reagents and conditions: (a) i. Trityl chloride (1.2 equiv ), pyridine, 50 °C, 32 h; ii. PhCOCl (4.8 equiv), < 40 °C, 24 h; 71% (for
two steps). (b) CH2Cl2–HOAc–Ac2O–H2SO4 = 1:1:0.6:0.175, r.t., 20 h, 83%. (c) Benzylamine (4.0 equiv), THF, r.t., 24 h, 88%. (d) CCl3CN
(3.3 equiv), DBU (0.3 equiv), r.t., 5 h, 86%.
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J. Ning et al.
LETTER
Scheme 4 Reagents and conditions: (a) Dodecyl alcohol (2 equiv), TMSOTf (0.05 equiv), CH2Cl2, r.t., 3 h, 89%. (b) MeOH–0.5% HCl, r.t.,
12–14 h, 93–96%. (c) 17 (1.4 equiv), TMSOTf (0.02 equiv), MS 4 Å, CH2Cl2, r.t., 2 h, 86%. (d) 2,3,4,6-Tetra-O-Bz-a-D-galactopyranosyl tri-
chloroacetimidate (1.0 equiv), TMSOTf (0.02 equiv), MS 4 Å, CH2Cl2, –45 °C, 2 h, 82%. (e) 2,3,5-Tri-O-Bz-a-L-arabinofuranosyl trichloroa-
cetimidate (1.3 equiv), CH2Cl2, TMSOTf (0.02 equiv), r.t., 2 h, 84% for 23, 85% for 28. (f) 8 (1.4 equiv), TMSOTf (0.02 equiv), MS 4 Å,
CH2Cl2, r.t., 2 h. 87%. (g) 13 (1.4 equiv.), TMSOTf (0.02 equiv.), MS 4 Å, CH2Cl2, r.t., 2 h. 85%. (h) CH3OH sat. with anhyd NH3, r.t., 72 h,
95% for 1, 96% for 2.
Scheme 5 Reagents and conditions: (a) Dodecyl alcohol (2 equiv), TMSOTf (0.05 equiv), CH2Cl2, r.t., 3 h, 91%. (b) MeOH–0.5% HCl, r.t.,
12–14 h, 93–96%. (c) 8 (1.0 equiv), TMSOTf (0.02 equiv), MS 4 Å, CH2Cl2, –45 °C, 2 h, 84%. (d) 2,3,5-Tri-O-Bz-a-L-arabinofuranosyl tri-
chloroacetimidate (1.3 equiv), CH2Cl2, TMSOTf (0.02 equiv), r.t., 2 h, 85% for 32, 81% for 37. (e) 17 (1.3 equiv), TMSOTf (0.02 equiv), MS
4 Å, CH2Cl2, r.t., 2 h, 86%. (f) 2,3,4,6-Tetra-O-Bz-a-D-galactopyranosyl trichloroacetimidate (1.0 equiv), TMSOTf (0.02 equiv.), MS 4 Å,
CH2Cl2, –45 °C, 2 h, 83%. (g) CH3OH sat. with anhyd NH3, r.t., 72 h, 94% for 3, 97% for 4.
Synlett 2003, No. 14, 2208–2212 © Thieme Stuttgart · New York

LETTER
Synthesis of 2,6-Branched Galacto-Oligosaccharides
2211
For 13: [a]D +21.2 (c 1.0, CHCl3). 1H NMR (400 MHz,
CDCl3): d = 8.71 (s, 1 H, CNHCCl3), 8.06–7.33 (m, 15 H, 3
× PhH), 6.79 (d, J1,2 = 3.6 Hz, 1 H, H-1), 6.11 (dd, 1 H, H-
4), 5.86 (dd, 1 H, H-3), 5.72 (dd, 1 H, H-2), 4.80 (m, 1 H, H-
5), 4.58 (dd, 1 H, H-6a), 4.40 (dd, 1 H, H-6b), 1.98 (s, 3 H,
CH3CO). Anal. Calcd for C31H26NO10CI3: C, 54.84; H, 3.86.
Found: C, 54.72; H, 3.90.
specifically afforded the pentasaccharide 36 in 83% yield.
Condensation of 36 with 2,3,5-tri-O-Bz-a-L-arabino-
furanosyl trichloroacetimidate afforded the blocked hexa-
saccharide 37 in 81% yield. Deprotection of 34 and 37
gave the free tetrasaccharides 3 and hexasaccharide 4 as
amorphous white solids.
For 17: [a]D +55 (c 1.0, CHCl3). 1H NMR (400 MHz,
CDCl3): d = 8.73 (s, 1 H, CNHCCl3), 8.04–7.31 (m, 10 H, 2
× PhH), 6.76 (d, J1,2 = 3.6 Hz, 1 H, H-1), 6.00 (dd, 1 H, H-
4), 5.81 (dd, 1 H, H-3), 5.68 (dd, 1 H, H-2), 4.65 (m, 1 H, H-
5), 4.22 (m, 2 H, H-6a,b), 1.98, 1.97 (2 × s, 6 H, 2 CH3CO).
Anal. Calcd for C26H24Cl3NO10: C, 50.63; H, 3.92. Found: C,
50.79; H, 3.85.
All new compounds involved in this study were identified
by optical rotations, 1H NMR or/and 13C NMR spectros-
copy, and elemental analyses or MALDI–TOF MS. Se-
lected physical data for some key compounds are given in
references.11
In summary, an efficient method for the preparation of
2,6-branched galacto-oligosaccharides has been devel-
oped by regio- and stereoselective glycosylation using
glycosyl trichloroacetimidates as the donors and partially
protected sugars as the acceptor. This method can be used
to synthesize both homo- and hetero- saccharide struc-
tures, which are used for the further assembly of advanced
bioactive sugar chains. The sole use of acyl groups in the
synthesis substantially simplified the procedure.
For 19: [a]D +67.8° (c 1.0, CHCl3). 1H NMR (400 MHz,
CDCl3): d = 8.13–7.25 (m, 15 H, 3 × PhH), 5.85 (dd, 1 H, H-
2), 5.81 (dd, 1 H, H-4), 5.58 (dd, 1 H, H-3), 4.79 (d, J1,2 = 7.9
Hz, 1 H, H-1), 4.03 (m, 1 H, H-5), 3.97–3.54 (m, 4 H, H-
6a,6b, CH2C11H23), 1.56–0.86 (m, 23 H, CH2C11H23). Anal.
Calcd for C39H48O9: C, 70.89; H, 7.32. Found: C, 70.51; H,
7.39.
For 21: [a]D +85.3 (c 1.0, CHCl3). 1H NMR (400 MHz,
CDCl3): d = 8.04–7.22 (m, 25 H, 5 × PhH), 6.00 (dd, 1 H, H-
4), 5.74 (dd, 1 H, H-2), 5.62 (dd, 1 H, H-4), 5.56 (dd, 1 H, H-
3), 5.29 (dd, 1 H, H-3), 4.77 (d, J1,2 = 7.9 Hz, 1 H, H-1), 4.52
(d, J1,2 = 7.6 Hz, 1 H, H-1), 1.60–0.81 (m, 23 H, CH2C11H23).
Anal. Calcd for C59H66O16: C, 68.72; H, 6.45. Found: C,
68.49; H, 6.52.
Acknowledgment
For 22: [a]D +83.8 (c 1.0, CHCl3). 1H NMR (400 MHz,
CDCl3): d = 8.10–7.22 (m, 45 H, 9 × PhH), 5.99 (dd, 1 H, H-
4), 5.90 (dd, 1 H, H-4), 5.78–5.74 (m, 2 H, H-2,4), 5.68 (dd,
1 H, H-2), 5.59 (dd, 1 H, H-3), 5.53 (dd, 1 H, H-3), 5.24 (dd,
1 H, H-3), 4.79 (d, J1,2 = 7.9 Hz, 1 H, H-1), 4.63 (d, J1,2 = 7.8
Hz, 1 H, H-1), 4.46 (d, J1,2 = 7.6 Hz, 1 H, H-1), 1.60–0.86
(m, 23 H, CH2C11H23). Anal. Calcd for C93H92O25: C, 69.39;
H, 5.76. Found: C, 69.62; H, 5.81.
This work was supported by the Beijing Natural Science Founda-
tion (6021004) and by The Ministry of Science and Technology
(2001AA246014).
References
(1) (a) Plante, O. J.; Palmacci, E. R.; Seeberger, P. H. Science
2001, 291, 1523. (b) Sears, P.; Wong, C. H. Science 2001,
291, 2344.
(2) Ning, J.; Yi, Y.; Kong, F. Tetrahedron Lett. 2002, 43, 5545.
(3) (a) Xing, Y.; Ning, J. Tetrahedron: Asymmetry 2003, 14,
1275. (b) Ning, J.; Heng, L.; Kong, F. Tetrahedron Lett.
2002, 43, 673.
(4) Ning, J.; Wang, H.; Yi, Y. Tetrahedron Lett. 2002, 43, 7349.
(5) Wang, H.; Ning, J. J. Org. Chem. 2003, 68, 2521.
(6) Puhlmann, J.; Bucheli, E.; Swain, M. J.; Dunning, N.;
Albersheim, P.; Darvill, A. G.; Hahn, M. Plant Physiol.
1994, 104, 699.
(7) (a) Yamada, H.; Kiyohara, H.; Cyong, J.-C.; Otsuka, Y.
Carbohydr. Res. 1987, 159, 275. (b) Yamada, H.
Carbohydr. Polym. 1994, 25, 269.
(8) (a) Timmers, C. M.; Wigchert, S. C. M.; Leeuwenburgh, M.
A.; van der Marel, G. A.; van Boom, J. H. Eur. J. Org. Chem.
1998, 91. (b) Borbás, A.; Jánossy, L.; Lipták, A. Carbohydr.
Res. 1999, 318, 98. (c) Csávas, M.; Borbás, A.; Jánossy, L.;
Lipták, A. Tetrahedron Lett. 2003, 44, 631.
(9) Ning, J.; Kong, F. Carbohydr. Res. 2001, 330, 165.
(10) Rio, S.; Beau, J. M.; Jacquinet, J. C. Carbohydr. Res. 1991,
219, 71.
For 23: [a]D +48.6° (c 1.0, CHCl3). 1H NMR (400 MHz,
CDCl3): d = 7.98–7.12 (m, 60 H, 12 × PhH), 6.02 (dd, 1 H,
H-4), 5.86 (dd, 1 H, H-4), 5.77 (dd, 1 H, H-4), 5.70 (dd, 1 H,
H-2), 5.64 (dd, 1 H, H-2), 5.58–5.52 (m, 3 H, 3 × H-3), 5.49
(s, 1 H, H-1), 5.37 (d, J2,3 = 1.5 Hz, 1 H, H-2), 5.35 (dd, 1 H,
H-3), 4.70 (d, J1,2 = 8.0 Hz, 1 H, H-1), 4.59 (d, J1,2 = 7.6 Hz,
1 H, H-1), 4.53 (d, J1,2 = 7.9 Hz, 1 H, H-1), 1.36–0.86 (m, 23
H, CH2C11H23). 13C NMR (100 MHz, CDCl3): d = 166.19,
165.77, 165.48, 165.47, 165.41, 165.28, 165.23, 165.19,
165.16, 165.11, 165.0, 164.96 (12 PhCO), 106.51, 101.68,
101.44, 100.86 (4 C-1). Anal. Calcd for C119H112O32: C,
69.58; H, 5.50. Found: C, 69.23; H, 5.59.
For 25: [a]D +75.5 (c 1.0, CHCl3). 1H NMR (400 MHz,
CDCl3): d = 8.13–7.23 (m, 30 H, 6 × PhH), 5.92 (dd, 1 H, H-
4), 5.80 (dd, 1 H, H-2), 5.76 (dd, 1 H, H-4), 5.68 (dd, 1 H, H-
2), 5.53 (dd, 1 H, H-3), 5.50 (dd, 1 H, H-3), 4.83 (d, J1,2 = 7.9
Hz, 1 H, H-1), 4.63 (d, J1,2 = 8.0 Hz, 1 H, H-1), 1.39–0.87
(m, 23 H, CH2C11H23). Anal. Calcd for C66H70O17: C, 69.83;
H, 6.21. Found: C, 69.91; H, 6.37.
For 27: [a]D +86.5 (c 1.0, CHCl3). 1H NMR (400 MHz,
CDCl3): d = 8.05–7.15 (m, 45 H, 9 × PhH), 5.94 (dd, 1 H, H-
4), 5.86 (dd, 1 H, H-4), 5.83 (d, 1 H, H-4), 5.77 (dd, 1 H, H-
2), 5.68 (dd, 1 H, H-2), 5.55 (dd, 1 H, H-3), 5.52 (dd, 1 H, H-
3), 5.32 (dd, 1 H, H-3), 4.87 (d, J1,2 = 7.9 Hz, 1 H, H-1), 4.67
(d, J1,2 = 7.9 Hz, 1 H, H-1), 4.52 (d, J1,2 = 7.7 Hz, 1 H, H-1),
1.40–0.86 (m, 23 H, CH2C11H23). Anal. Calcd for C93H92O25:
C, 69.39; H, 5.76. Found: C, 69.48; H, 5.81.
(11) All new compounds gave satisfactory elemental analysis
results. Selected physical data for some key compounds are
as follows:
For 8: [a]D +20.9 (c 1.0, CHCl3). 1H NMR (400 MHz,
CDCl3): d = 8.66 (s, 1 H, CNHCCl3), 8.08–7.26 (m, 15 H, 3
× PhH), 6.89 (d, J1,2 = 3.6 Hz, 1 H, H-1), 6.06 (dd, 1 H, H-
4), 6.05 (dd, 1 H, H-3), 5.94 (dd, 1 H, H-2), 4.72 (m, 1 H, H-
5), 4.28–4.26 (m, 2 H, H-6a,6b), 1.99 (s, 3 H, CH3CO). Anal.
Calcd for C31H26NO10CI3: C, 54.84; H, 3.86. Found: C,
54.69; H, 3.98.
For 28: [a]D +56.0 (c 1.0, CHCl3). 1H NMR (400 MHz,
CDCl3): d = 8.07–7.20 (m, 60 H, 12 × PhH), 6.01 (dd, 1 H,
H-4), 5.88 (dd, 1 H, H-4), 5.79 (dd, 1 H, H-4), 5.70 (dd, 1 H,
H-2), 5.68 (dd, 1 H, H-2), 5.54–5.49 (m, 3 H, 3 × H-3), 5.46
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J. Ning et al.
LETTER
(dd, 1 H, H-3), 5.45 (s, 1 H, H-1), 5.36 (d, J2,3 = 1.2 Hz, 1 H,
H-2), 4.65 (d, 1 H, J1,2 = 8.2 Hz, H-1), 4.63 (d, 1 H, J1,2 = 8.2
Hz, H-1), 4.51 (d, 1 H, J1,2 = 7.6 Hz, 1 H, H-1). 1.35–0.85
(m, 23 H, CH2C11H23). 13C NMR (100 MHz, CDCl3): d =
166.21, 165.73, 165.47, 165.43, 165.40, 165.33,165.33,
165.29, 165.21, 165.07, 165.07, 164.98 (12 PhCO), 106.27,
101.46, 101.19, 100.93 (4 C-1). Anal. Calcd for C119H112O32:
C, 69.58; H, 5.50. Found: C, 69.74; H, 5.46.
2), 4.80 (d, J1,2 = 7.9 Hz, 1 H, H-1), 4.51 (d, J1,2 = 7.8 Hz, 1
H, H-1), 1.4–0.86 (m, 23 H, CH2C11H23). Anal. Calcd for
C85H86O23: C, 69.19; H, 5.87. Found: C, 69.44; H, 5.91.
For 34: [a]D +77.6 (c 1.0, CHCl3). 1H NMR (400 MHz,
CDCl3): d = 8.01–7.13 (m, 50 H, 10 × PhH), 5.89 (dd, 1 H,
H-4), 5.85 (dd, 1 H, H-4), 5.72 (dd, 1 H, H-4), 5.70 (dd, 1 H,
H-2), 5.55-5.47 (m, 3 H, 3 × H-3), 5.43 (s, 1 H, H-1), 5.36
(d, J1,2 = 1.1 Hz, 1 H, H-2), 5.35 (dd, 1 H, H-3), 5.25 (dd, 1
H, H-3), 4.82 (d, J1,2 = 7.8 Hz, 1 H, H-1), 4.52 (d, J1,2 = 7.8
Hz, 1 H, H-1), 4.46 (d, J1,2 = 7.9 Hz, 1 H, H-1), 1.89, 1.88 (2
For 1: [a]D –6.5 (c 1.0, H2O). 1H NMR (400 MHz, D2O): d =
5.26 (s, 1 H, H-1), 4.48 (d, J1,2 = 6.0 Hz, 1 H, H-1), 4.39 (d,
J1,2 = 7.6 Hz, 1 H, H-1), 4.30 (d, J1,2 = 6.0 Hz, 1 H, H-1),
1.58–0.83 (m, 23 H, CH2C11H23). MALDI–TOF MS: m/z
calcd for C35H64O20: 804.88 [M] , found: 827.54 (M + Na)+.
For 2: [a]D –8.6 (c 1.0, H2O). 1H NMR (400 MHz, D2O): d =
5.33 (s, 1 H, H-1), 4.55 (d, J1,2 = 6.0 Hz, 1 H, H-1), 4.46 (d,
J1,2 = 6.0 Hz, 1 H, H-1), 4.38 (d, J1,2 = 6.0 Hz, 1 H, H-1),
1.66–0.92 (m, 23 H, CH2C11H23). MALDI–TOF MS: m/z
calcd for C35H64O20: 804.88 [M], found: 827.81 (M + Na)+.
For 30: [a]D +82.7 (c 1.0, CHCl3). 1H NMR (400 MHz,
CDCl3): d = 8.08–7.26 (m, 10 H, 2 × PhH), 5.71 (dd, 1 H, H-
4), 5.38 (dd, 1 H, H-3), 4.51 (d, J1,2 = 7.7 Hz, 1 H, H-1), 4.13
(dd, 1 H, H-2), 3.98(dd, 1 H, H-6a), 3.93 (m, 1 H, H-5), 3.78
(dd, 1 H, H-6b), 3.64–3.59 (m, 2 H, CH2C11H23), 1.36–0.86
(m, 23 H, CH2C11H23). Anal. Calcd for C32H44O8: C, 69.04;
H, 7.97. Found: C, 69.19; H, 8.04.
× s, 6 H, 2 × CH3CO), 1.36–0.86 (m, 23 H, CH2C11H23). 13
C
NMR (100 MHz, CDCl3): d = 170.18, 169.23 (2 × CH3CO),
166.08, 165.57, 165.44, 165.44, 165.40, 165.27, 165.20,
165.11, 165.04, 164.87 (10 × PhCO), 106.03, 101.98,
100.94, 100.22 (4 × C-1) 20.53, 20.44 (2 × CH3CO). Anal.
Calcd for C109H108O32: C, 67.83; H, 5.64. Found: C, 67.68;
H, 5.69.
For 37: [a]D +37.5 (c 1.0, CHCl3). 1H NMR (400 MHz,
CDCl3): d = 5.41 (s, 1 H, H-1), 5.30 (s, 1 H, H-1), 4.65 (d,
J1,2 = 7.6 Hz, 1 H, H-1), 4.47 (d, J1,2 = 7.7 Hz, 1 H, H-1), 4.39
(d, J1,2 = 7.7 Hz, 1 H, H-1), 4.32 (d, J1,2 = 7.5 Hz, 1 H, H-1).
13C NMR (100 MHz, CDCl3): d = 106.17, 106.02, 101.92,
101.22, 100.90, 100.82 (6 × C-1). Anal. Calcd for
C165H150O46: C, 69.08; H, 5.27. Found: C, 69.54; H, 5.17.
For 3: [a]D –17.5 (c 1.0, H2O). 1H NMR (400 MHz, D2O):
d = 5.22 (s, 1 H, H-1), 4.38, 4.36, 4.11 (d, 3 H, 3 × H-1),
1.54–0.79 (m, 23 H, CH2C11H23). MALDI–TOF MS: m/z
calcd for C35H64O20: 804.88 [M], found: 827.65 (M + Na)+.
For 4: [a]D –6.8 (c 1.0, H2O). 1H NMR (400 MHz, D2O): d =
5.25 (s, 1 H, H-1), 5.23 (s, 1 H, H-1), 4.52 (d, J1,2 = 6.8 Hz,
1 H, H-1), 4.01–4.39 (m, 3 H, H-1), 1.56–0.84 (m, 23 H,
CH2C11H23). 13C NMR (100 MHz, D2O): d = 108.23, 108.23,
103.45, 103.45, 103.25, 102.17 (6 × C-1). MALDI-TOF MS:
m/z calcd for C46H82O29: 1099.14 [M], found: 1122.26 (M +
Na)+.
For 31: [a]D +88.3 (c 1.0, CHCl3). 1H NMR (400 MHz,
CDCl3): d = 8.07–7.24 (m, 25 H, 5 × PhH), 5.83 (dd, 1 H, H-
4), 5.78 (dd, 1 H, H-4), 5.73 (dd, 1 H, H-2), 5.50 (dd, 1 H, H-
3), 5.29 (dd, 1 H, H-3), 4.84 (d, J1,2 = 7.9 Hz, 1 H, H-1), 4.37
(d, J1,2 = 7.7 Hz, 1 H, H-1), 1.35–0.86 (m, 23 H, CH2C11H23).
Anal. Calcd for C61H68O17: C, 68.27; H, 6.39. Found: C,
68.19; H, 6.35.
For 33: [a]D +73.4 (c 1.0, CHCl3). 1H NMR (400 MHz,
CDCl3): d = 8.01–7.13 (m, 40 H, 8 × PhH), 5.87 (dd, 1 H, H-
4), 5.78 (dd, 1 H, H-2), 5.74 (dd, 1 H, H-4), 5.52–5.47 (m, 3
H, 3 × H-3), 5.36 (s, 1 H, H-1), 5.21 (d, J1,2 = 0.9 Hz, 1 H, H-
Synlett 2003, No. 14, 2208–2212 © Thieme Stuttgart · New York