Synthesis of a mannose heptasaccharide existing in baker's yeast, Saccharomyces cerevisiae X2180-1A wild-type strain

Article abstract of DOI:10.1016/S0008-6215(02)00402-0

A mannose heptasaccharide existing in baker's yeast, Saccharomyces cerevisiae X2180-1A wild-type strain, was effectively synthesized as its allyl glycoside via TMSOTf-promoted condensation of a disaccharide donor 13 with a pentasaccharide acceptor 12, fol

Full text of DOI:10.1016/S0008-6215(02)00402-0

Carbohydrate Research 338 (2003) 5–9
www.elsevier.com/locate/carres
Synthesis of a mannose heptasaccharide existing in baker’s yeast,
Saccharomyces cere6isiae X2180-1A wild-type strain
Youlin Zeng, Jianjun Zhang, Jun Ning, Fanzuo Kong*
Research Center for Eco-En6ironmental Sciences, Academia Sinica, P.O. Box 2871, Beijing 100085, China
Received 8 July 2002; accepted 9 October 2002
Abstract
A mannose heptasaccharide existing in baker’s yeast, Saccharomyces cere6isiae X2180-1A wild-type strain, was effectively
synthesized as its allyl glycoside via TMSOTf-promoted condensation of a disaccharide donor 13 with a pentasaccharide acceptor
12, followed by deprotection. The pentasaccharide 12 was constructed by coupling of 2,3,4,6-tetra-O-benzoyl-a-
osyl-(1“3)-2,4,6-tri-O-benzoyl-a- -mannopyranosyl-(1“2)-3,4,6-tri-O-benzoyl-a- -mannopyranosyl-(1“2)-3,4,6-tri-O-benzoyl-
a- -mannopyranosyl trichloroacetimidate (9) with allyl 6-O-acetyl-3,4-di-O-benzoyl-a- -mannopyranoside (10), followed by
deacetylation. The tetrasaccharide 9 was obtained by coupling of 2,3,4,6-tetra-O-benzoyl-a- -mannopyranosyl-(1“3)-2,4,6-tri-O-
benzoyl-a- -mannopyranosyl trichloroacetimidate (5) with allyl 3,4,6-tri-O-benzoyl-a- -mannopyranosyl-(1“2)-3,4,6-tri-O-ben-
zoyl-a- -mannopyranoside (6), followed by deallylation and trichloroacetimidation. The disaccharides 6 and 13 were readily
D-mannopyran-
D
D
D
D
D
D
D
D
obtained by known methods. © 2002 Elsevier Science Ltd. All rights reserved.
Keywords: Mannose oligosaccharides; Trichloroacetimidates; Regio- and stereoselective synthesis
1. Introduction
2. Results and discussion
a-Linked oligo-
D
-mannosyl side chains of cell-wall
D
-
Structural analysis indicated that the mannose hep-
tamer can be constructed with a (1“6)-linkage by
condensation of two moieties, i.e., a mannose dimer
donor 13 and a mannose pentamer acceptor 12. The
pentasaccharide then can be constructed from a man-
nose acceptor 10 and a tetrasaccharide donor 9, which
can be built from a (1“3)-linked disaccharide donor 5
and a (1“2)-linked disaccharide acceptor 6. The disac-
charide acceptor 6 can be obtained by self conden-
sation of 1,2-O-allyloxyethylidene-3,4,6-tri-O-benzoyl-
mannan of the pathogenic yeast Candida species plays
important roles in the binding of yeast cells to the
marginal zone of mouse spleen1 and in the mechanism
of several types of yeast flocculation.2 These facts seem
of interest from the viewpoints of both host–parasite
interactions and the biological roles of mannan. Mild
acetolysis and NMR studies3 of the
charomyces cere6isae X2180-1A wild-type strain re-
vealed that 1A have a highly branched structure, and a
D-mannan of Sac-
b-D-mannopyranose, followed by selective 2-O-
D
-mannoheptaose containing a-(1“3)-, a-(1“2)-, a-
deacetylation.
(1“6)-linkages, was isolated after mild acetolysis (Fig.
1). To the best of our knowledge, there have been no
reports dealing with the synthesis of this branched
heptasaccharide. For an investigation of structure–
function relationships of mannan, we present herein a
facile and convergent synthesis of the mannose
heptasaccharide.
Our synthetic route is shown in Scheme 1. Removal
of benzylidene and ethylidene groups of compound 14
was readily achieved simultaneously with 90% aq acetic
acid under reflux within 2 h, giving the disaccharide 2
as a white solid in high yield (96%) after purification.
Benzoylation of 2 with benzoyl chloride in pyridine,
followed by selective 1-O-debenzoylation with M solu-
tion of ammonia in 1:2 methanol–tetrahydrofuran, and
then trichloroacetimidation5 with trichloroacetonitrile
in the presence of DBU furnished 2,3,4,6-tetra-O-ben-
* Corresponding author. Tel.: +86-10-62936613; fax: +
86-10-62923563
E-mail address: fzkong@mail.rcees.ac.cn (F. Kong).
0008-6215/03/$ - see front matter © 2002 Elsevier Science Ltd. All rights reserved.
PII: S0008-6215(02)00402-0

6
Y. Zeng et al. / Carbohydrate Research 338 (2003) 5–9
Fig. 1. Structure of the isolated mannoheptaose.
zoyl-a-
D
-mannopyranosyl-(1“3)-2,4,6-tri-O-benzoyl-
3,4-di-O-benzoyl-a-
tained as a byproduct of the coupling reaction of
2,6-di-O-acetyl-3,4-di-O-benzoyl-a- -mannopyranosyl
trichloroacetimidate (16) with allyl alcohol. This cou-
pling gave allyl 2,6-di-O-acetyl-3,4-di-O-benzoyl-a-
mannopyranoside (17) and 10 in a ratio of 3.5:1. When
compound 17, which is used as a basic material in the
synthesis of 2-branched (1“6)-linked mannans,9 was
prepared in large quantities, 10 was obtained in sub-
D
-mannopyranoside (10), was ob-
a- -mannopyranosyl trichloroacetimidate (5) in 65%
D
yield (for three steps). Condensation of the disaccharide
donor 5 with the disaccharide acceptor 66,7 gave the
tetrasaccharide 7 in 61% yield. Deallylation8 of 7 with
PdCl2 in dichloromethane furnished the tetrasaccharide
hemiacetal 8, and subsequent trichloroacetimidation
produced the tetrasaccharide donor 9 (81% for two
steps). The monosaccharide acceptor, allyl 6-O-acetyl-
D
D-
Scheme 1. Conditions and reagents: a: 90% HOAc–H2O, reflux, 2 h; b: BzCl, pyridine, RT; c: THF, MeOH, NH3, RT; d:
CCl3CN, DBU, CH2Cl2, RT, 8 h; e: TMSOTf, CH2Cl2, N2, −15 °C to RT, 4 h; f: PdCl2, CH2Cl2, RT, 2 h. g: CH2Cl2,
MeOH–AcCl, RT; h: MeOH, NH3, RT, 7 d.

Y. Zeng et al. / Carbohydrate Research 338 (2003) 5–9
7
stantial amounts. Compound 16 was prepared by 1-O-
deacetylation of 1,2,6-tri-O-acetyl-3,4-di-O-benzoyl-a-
petroleum ether–EtOAc) indicated that the reaction
was complete. The reaction mixture was washed with
dilute hydrochloric acid and extracted with CH2Cl2.
The organic phase was dried over anhyd Na2SO4, then
concentrated to dryness. The resultant crude product 3
was dissolved in a M solution of NH3 in MeOH (400
mL) and stirred at rt until TLC (3:1 petroleum ether–
EtOAc) indicated that the reaction was complete. The
solution was concentrated to give compound 4 as a
syrup. A mixture of 4, trichloroacetonitrile (3.2 mL, 15
mmol), and 1,8-diazabicyclo[5.4.0]undecene (DBU)
(0.50 mL, 4.04 mmol) in dry CH2Cl2 (50 mL) was
stirred under nitrogen for 3 h and then concentrated.
The residue was purified by flash chromatography (2:1
petroleum ether–EtOAc) to give 5 (6.58 g, 65% for
three steps from 2 to 5) as a white foam: [a]D −49.2°
D-mannopyranose, followed by trichloroacetimidation.
The use of the acceptor 10 made the synthesis simple
and practical, since it allowed one to build a difficultly
accessible (1“2)-linkage first, then build an easily ac-
cessible (1“6)-linkage. Therefore, condensation of the
tetrasaccharide donor 9 with 10, followed by selective
6-O-deacetylation, produced the pentasaccharide accep-
tor 12. Finally, condensation of the pentrasacchride
acceptor 12 with disaccharide donor 136 furnished the
heptasaccharide 14 (82%), and subsequent deacylation
in ammonia-saturated methanol yielded the target allyl
mannoheptaoside 15, whose bioassay is in progress.
In summary, a convergent and facile synthesis of
branched mannoheptaose containing (1“2)-, (1“3)-,
and (1“6)-linkages was achieved. The method pre-
sented is simpler and more practical compared to those
for the synthesis of mannans with similar structures. It
should be possible to carry out a large-scale synthesis
employing the described method.
1
(c 1.0, CHCl3); H NMR (400 MHz, CDCl3): d 8.85 (s,
1 H, NH), 8.11–7.20 (m, 35 H, 7 BzꢀH), 6.60 (d, 1 H,
J1,2 1.8 Hz, H-1), 6.15 (dd, 1 H, J3,4=J4,5=9.8 Hz,
H-4%), 6.06 (dd, 1 H, J3,4=J4,5=9.8 Hz, H-4), 5.87 (dd,
1 H, J1,2 1.4, J2,3 2.8 Hz, H-2%), 5.72 (dd, 1 H, J2,3 2.8,
J3,4 9.8 Hz, H-3%), 5.43–5.33 (m, 2 H, H-1%, H-2),
4.76–4.70 (m, 2 H, H-3, H-6%), 4.58–4.47 (m, 4 H, 2
H-5, 2 H-6), 4.35 (dd, 1 H, J5,6 2.7, J6,6 12.3 Hz, H-6).
13C NMR (100 MHz, DCCl3): d 165.7, 165.7, 165.5,
165.0, 164.8, 164.5, 164.4 (7 C, 7 PhCO), 159.4 (1 C,
C(NH)CCl3), 133.5–132.6, 130.0–127.7 (PhCO), 99.5,
94.3 (2 C, 2 C-1), 90.4 (1 C, C(NH)CCl3), 75.6, 71.4,
70.1, 69.9, 69.6, 69.1, 67.5, 66.1, 62.2, 62.1 (C-2–6).
Anal. Calcd for C63H50Cl3NO18: C, 62.26; H, 4.15.
Found: C, 62.06; H, 4.20.
3. Experimental
3.1. General methods
Optical rotations were determined at 25 °C with a
Perkin–Elmer Model 241-Mc automatic polarimeter.
1H NMR 13C and NMR spectra were recorded with
1
Bruker ARX 400 spectrometers (400 MHz for H, 100
MHz for 13C) at 25 °C for solutions in CDCl3 or D2O
as indicated. Mass spectra were recorded with a VG
PLATFORM mass spectrometer in the electrospray-
ionization (ESI) mode. 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 a UV lamp. Column chromatography was
conducted on columns (16×240 mm, 18×300 mm,
35×400 mm) of silica gel (100–200 mesh) with
EtOAc–petroleum ether (60–90 °C) as the eluent. Solu-
tions were concentrated at B60 °C under reduced
pressure.
3.3. 2,3,4,6-Tetra-O-benzoyl-a-
3)-2,4,6-tri-O-benzoyl-a- -mannopyranosyl-(1“2)-
3,4,6-tri-O-benzoyl-a- -mannopyranosy-(1“2)-3,4,6-
-mannopyranosyl trichloroacetimidate
D-mannopyranosyl-(1“
D
D
tri-O-benzoyl-a-
D
(9)
To a cooled solution (0 °C) of 5 (1.70 g, 1.40 mmol)
and 6 (1.34 g, 1.33 mmol) in anhyd CH2Cl2 (50 mL)
was added TMSOTf (5 mL, 0.02 mmol). The mixture
was stirred at this temperature for 2 h, and then
quenched with Et3N (2 drops). The solvent was evapo-
rated to give a residue, which was purified by silica gel
column chromatography (3:2 petroleum ether–EtOAc)
to give tetrasaccharide 7 as a foamy solid (1.76 g, 61%).
To a solution of 7 (1.71 g, 0.82 mmol) in anhyd MeOH
(20 mL) was added PdCl2 (80 mg). After stirring the
mixture at rt for 2 h, TLC (3:2 petroleum ether–
EtOAc) indicated that the reaction was complete. The
mixture was filtered, the solution was concentrated to
dryness, and the resultant residue was purified by flash
chromatography (2:1 petroleum ether–EtOAc) to give
8 as a white foam. A mixture of 8, trichloroacetonitrile
(0.6 mL, 2.79 mmol) and 1,8-diazabicyclo[5.4.0]-
undecene (DBU) (0.06 mL, 0.39 mmol) in dry CH2Cl2
3.2. 2,3,4,6-Tetra-O-benzoyl-a-
D
-mannopyranosyl-(1“
3)-2,4,6-tri-O-benzoyl-a-D-mannopyranosyl trichloroace-
timidate (5)
To a solution of 90% HOAc (250 mL) was added 1
(7.58 g, 8.69 mmol), and the mixture was refluxed for
2.5 h and then concentrated to dryness. The residue was
passed through
a short silica gel column (1:1.5
petroleum ether–EtOAc) to give 2 (6.32 g, 96%) as a
white solid. The white solid was dissolved in pyridine
(40 mL), and then benzoyl chloride (20 mL) was added.
After stirring the mixture at rt for 12 h, TLC (3:2

8
Y. Zeng et al. / Carbohydrate Research 338 (2003) 5–9
(10 mL) was stirred under nitrogen for 3 h and then
concentrated. The residue was purified by flash
chromatography (2:1 petroleum ether–EtOAc) to give
9 (1.44 g, 81% for two steps) as a white foam: [a]D
4.45 (ddd, 1 H, J4,5 10.0, J5,6=J5,6%=12.3 Hz, H-5),
4.34 (dd, 1 H, J5,6=12.3, J6,6%=4.8 Hz, H-6), (dd, 1 H,
J5,6%=12.3, J6,6%=4.8 Hz, H-6%). Anal. Calcd for
C26H24Cl3NO10: C, 50.59; H, 4.24, Found: C, 50.74; H,
4.35.
1
−41.5° (c 1.0, CHCl3); H NMR (400 MHz, CDCl3): d
8.74 (s, 1 H, NH), 8.18–7.15 (m, 65 H, 13 BzꢀH), 6.58
(d, 1 H, J1,2 2.2 Hz, H-1), 6.08 (dd, 1 H, J3,4=J4,5
=
3.5. Allyl 2,3,4,6-tetra-O-benzoyl-a-
(1“3)-2,4,6-tri-O-benzoyl-a- -mannopyranosyl-(1“2)-
3,4,6-tri-O-benzoyl-a- -mannopyranosy-(1“2)-3,4,6-
tri-O-benzoyl-a- -mannopyranosyl-(1“2)-3,4-di-O-
benzoyl-a- -mannopyranoside (12)
D-mannopyranosyl-
10.0 Hz, H-4§), 6.06 (dd, 1 H, J3,4=J4,5=10.0 Hz,
H-4¦), 6.02 (dd, 1 H, J3,4=J4,5=10.0 Hz, H-4%), 5.95
(dd, 1 H, J3,4=J4,5=10.0 Hz, H-4), 5.88 (dd, 1 H, J2,3
3.2, J3,4 10.0 Hz, H-3§), 5.81 (dd, 1 H, J2,3 3.2, J3,4 10.0
Hz, H-3%), 5.71 (dd, 1 H, J1,2 1.5, J2,3 3.2 Hz, H-2§),
5.68 (dd, 1 H, J2,3 3.2, J3,4 10.0 Hz, H-3), 5.53 (d, 1 H,
J1,2 1.5 Hz, H-1§), 5.38 (dd, 1 H, J1,2 1.5, J2,3 3.2 Hz,
H-2¦), 5.35 (d, 1 H, J1,2 1.5 Hz, H-1¦), 5.05 (d, 1 H, J1,2
1.5 Hz, H-1%), 4.70–4.13 (m, 14 H, 2 H-2, H-3¦, 4 H-5,
8 H-6). 13C NMR (100 MHz, DCCl3): d 166.0, 166.0,
165.8, 165.7, 165.3, 165.2, 165.2, 165.1, 165.1, 165.0,
164.8, 164.6, 164.4 (13 C, 13 PhCO), 159.8 (1 C,
C(NH)CCl3), 133.5–132.6, 130.0–127.7 (PhCO), 99.6,
99.6, 99.2, 96.1 (4 C, 4 C-1), 90.4 (1 C, C(NH)CCl3),
75.4, 73.8, 71.4, 71.3, 70.4, 70.4, 69.9, 69.9, 69.8, 69.6,
69.6, 69.4, 67.8, 66.8, 66.8, 66.0, 63.3, 63.0, 62.8, 61.9
(C-2–6). Anal. Calcd for C117H94Cl3NO34: C, 64.93; H,
4.38. Found: C, 64.73; H, 4.47.
D
D
D
D
Compound 11 (234 mg, 59%) was prepared by coupling
of 9 (347 mg, 0.16 mmol) with 10 (75 mg, 0.16 mmol)
under the same conditions as described for the synthesis
of 7 by coupling of 5 with 6. Compound 11 was
dissolved in anhyd MeOH (20 mL) and CH2Cl2 (10
mL), and to the mixture was added AcCl (0.12 mL).
The flask was stoppered, and the solution was stirred at
rt until TLC (3:2 petroleum ether–EtOAc) showed that
the starting material had disappeared (2 h). The solu-
tion was neutralized with Et3N, then concentrated to
dryness. The residue was passed through a short silica
gel column (3:2 petroleum ether–EtOAc) to give 12
(220 mg, 95%) as a white solid: [a]D −65.3° (c 1.0,
1
CHCl3); H NMR (400 MHz, CDCl3): d 8.14–7.10 (m,
3.4. Allyl 6-O-acetyl-3,4-di-O-benzoyl-a-
D-mannopyran-
75 H, 15 BzꢀH), 6.12 (dd, 1 H, J3,4=J4,5=9.98 Hz,
H-4), 6.04–5.69 (m, 9 H, H-2, 4 H-3, 4 H-4, CHꢁCH2),
5.41–5.18 (m, 7 H, 4 H-1, 4 H-3, H-2, CHꢁCH2), 4.95
(d, 1 H, J1,2 1.5 Hz, H-1), 4.85–3.73 (m, 21 H, 3 H-2,
H-3, 5 H-5, 10 H-6, ꢀCH2ꢀ; CHꢁCH2). 13C NMR (100
MHz, DCCl3): d 166.5, 165.8, 165.7, 165.7, 165.7,
165.5, 165.4, 165.3, 165.3, 165.2, 165.1, 165.0 164.8,
164.6, 164.4 (15 C, 15 PhCO), 133.4–132.6, 130.0–
127.8 (ꢀCH2ꢀCHꢁCH2, PhCO), 117.2 (1 C,
ꢀCH2ꢀCHꢁCH2), 100.2, 99.8, 99.4, 99.2, 97.5 (5 C, 5
C-1), 75.4, 71.2, 71.2, 71.0, 70.6, 70.4, 69.9, 69.9, 69.6,
69.6, 69.4, 69.4, 69.3, 69.3, 68.3, 68.3, 67.7, 67.2, 67.2,
66.0, 64.0, 63.5, 62.4, 61.8, 61.2, 60.2 (C-2–6,
ꢀCH2ꢀCHꢁCH2). Anal. Calcd for C138H116O41: C,
68.20; H, 4.81. Found: C, 67.93; H, 4.87.
oside (10)
Selective 1-O-deacetylation of 1,2,6-tri-O-acetyl-3,4-di-
-mannopyranose9 (5.14 g, 10 mmol) in a
O-benzoyl-a-
D
M solution of NH3 in MeOH and then trichloroacetim-
idation with CCl3CN in the presence of DBU furnished
2,6-di-O-acetyl-3,4-di-O-benzoyl-a-D-mannopyranosyl
trichloroacetimidate (16) (5.06 g, 82%, for two steps).
Coupling of 16 (2.00 g, 3.24 mmol) with allyl alcohol
(0.5 mL, 7.21 mmol) gave allyl 2,6-di-O-acetyl-3,4-di-
O-benzoyl-a-
mmol, 70%) as the major product and allyl 6-O-acetyl-
-mannopyranoside (10, 304 mg,
D-mannopyranoside (17, 1.28 g, 2.28
3,4-di-O-benzoyl-a-
D
0.65 mmol, 20%) as the minor one, the ratio of 17 to 10
1
is 3.5. For 10: [a]D −32.8° (c 1.0, CHCl3); H NMR
(400 MHz, CDCl3): d 7.97–7.26 (m, 10 H, 2 BzꢀH),
5.98 (m, 1 H, CHꢁCH2), 5.85 (dd, 1 H, J3,4=J4,5=10.0
Hz, H-4), 5.65 (dd, 1 H, J2,3 3.0, J3,4 10.0 Hz, H-3), 5.37
(dd, 1 H, J 1.5, J 17.2 Hz, CHꢁCH2), 5.27 (dd, 1 H, J
1.5, J 10.4 Hz, CHꢁCH2), 5.00 (d, 1 H, J1,2 1.5 Hz,
3.6. Allyl 2,3,4,6-tetra-O-benzoyl-a-
(1“3)-2,4,6-tri-O-benzoyl-a- -mannopyranosyl-(1“2)-
3,4,6-tri-O-benzoyl-a- -mannopyranosyl-(1“2)-3,4,6-
tri-O-benzoyl-a- -mannopyranosyl-(1“2)-[2,3,4-tri-O-
benzoyl-6-O-acetyl-a- -mannopyranosyl-(1“2)-3,4,6-
tri-O-benzoyl-a- -mannopyranosyl-(1“6)-]3,4-di-O-
benzoyl-a- -mannopyranoside (14)
D-mannopyranosyl-
D
D
D
D
H-1), 4.34–4.19 (m,
5
H, H-2, H-5, H-6,
2
D
CH2ꢀCHꢁCH2), 4.10 (dd, 1 H, J5,6% 6.14, J6,6% 12.8 Hz,
H-6%), 2.05 (s, 3 H, MeCO). Anal. Calcd for C25H26O9:
C, 63.82; H, 5.57, Found: C, 63.71; H, 5.56. For 16:
[a]D −19.8° (c 1.0, CHCl3); 1H NMR (400 MHz,
CDCl3): d 8.85 (s, 1 H, NH), 7.98–7.26 (m, 10 H, 2
BzꢀH), 6.40 (d, 1 H, J1,2 1.8 Hz, H-1), 5.90 (dd, 1 H,
D
Under the same conditions as described for the synthe-
sis of 7 by coupling of 5 with 6, heptasaccharide 14 (129
mg, 82%) was obtained from coupling of 13 (58 mg,
0.050 mmol) with 12 (113 mg, 0.046 mmol): [a]D
1
J3,4=J4,5=10.0 Hz, H-4), 5.80 (dd, 1 H, J2,3 3.4, J3,4
−31.2° (c 1.0, CHCl3); H NMR (400 MHz, CDCl3): d
10.0 Hz, H-3), 5.70 (dd, 1 H, J1,2 1.8, J2,3 3.4 Hz, H-2),
8.19–6.90 (m, 105 H, 21 BzꢀH), 6.20–5.74 (m, 17 H, 3

Y. Zeng et al. / Carbohydrate Research 338 (2003) 5–9
9
H-2, 6 H-3, 7 H-4, CHꢁCH2), 5.60 (d, 1 H, J1,2 1.5 Hz,
H-1), 5.52 (d, 1 H, J1,2 1.5 Hz, H-1), 5.47–5.31 (m, 5 H,
3 H-2, CHꢁCH2), 5.40 (d, 1 H, J1,2 1.5 Hz, H-1), 5.32
(d, 1 H, J1,2 1.5 Hz, H-1), 5.24 (d, 1 H, J1,2 1.5 Hz,
H-1), 5.13 (d, 1 H, J1,2 1.5 Hz, H-1), 4.92 (d, 1 H, J1,2
1.5 Hz, H-1), 4.77–4.02 (m, 25 H, H-2, H-3, 7 H-5, 14
H-6, CH2ꢀCHꢁCH2), 1.91 (s, 3 H, MeCO). 13C NMR
(100 MHz, CDCl3): l 169.0 (1 C, MeCO), 166.1, 166.0,
165.9, 165.8, 165.8, 165.7, 165.7, 165.6, 165.5, 165.4,
165.3, 165.3, 165.2, 165.2, 165.1, 165.1, 165.0, 164.9,
164.7, 164.5 (21 C, PhCO), 133.4–132.5, 130.2–127.9
(PhCO, ꢀCH2ꢀCHꢁCH2), 117.7 (1 C, ꢀCH2ꢀCHꢁCH2),
100.5, 100.0, 99.9, 99.4, 99.3, 98.7, 98.0 (7 C-1, JC-1,H-
1=175.1 to 177.3 Hz), 77.7, 75.8, 75.6, 71.3, 71.1, 71.0,
70.9, 70.5, 70.0, 69.8, 69.7, 69.6, 69.5, 68.8, 68.7, 67.6,
67.5, 67.4, 67.0, 66.3, 66.1, 63.8, 63.5, 63.4, 63.3, 61.9
(C-2–6, ꢀCH2ꢀCHꢁCH2), 20.4 (1 MeCO). Anal. Calcd
for C194H162O58: C, 68.10; H, 4.77. Found: C, 67.97; H,
4.69.
78.6, 78.4, 77.9, 73.3, 73.3, 73.3, 73.3, 73.3, 73.2, 71.2,
70.4, 70.4, 70.4, 70.1, 70.0, 70.0, 70.0, 69.6, 68.4, 67.0,
66.9, 66.9, 66.9, 66.9, 66.9, 66.7, 66.2, 65.7, 61.1, 61.1,
61.1, 60.9, 60.9, 60.9 (C-2–6, ꢀCH2ꢀCHꢁCH2). Anal.
Calcd for C45H76O36: C, 45.30; H, 6.42. Found: C,
45.17; H, 6.47.
Acknowledgements
This work was supported by The National Natural
Science Foundation of China (Projects 39970864 and
30070815).
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