Synthesis of blockwise alkylated (1→4) linked trisaccharides as surfactants: Influence of configuration of anomeric position on their surface activities

Article abstract of DOI:10.1016/j.carres.2011.04.034

New carbohydrate-based surfactants consisting of hydrophilic cellobiosyl and hydrophobic glucosyl residues, methyl β-D-glucopyranosyl-(1→4)- α-D-glucopyranosyl-(1→4)-2,3,6-tri-O-methyl-α-D- glucopyranoside 1 (GβGαMα, G: glucopyranosyl residue, α and β: α-(1→4)- and β-(1→4) glycosidic bonds, M: methyl group), 2 (G_βG_βM_α), 3 (G_βG_αM_β), 4 (G _βG_βM_β), 5 (G _βG_αE_α, E: ethyl group), 6 (G_βG_βE_α), 7 (G _βG_αE_β), 8 (G _βG_βE_β) and eight α-and β-glycoside mixtures (a mixture of 1 and 2: 1/2 = 62/38 (9), 32/68 (10); a mixture of 3 and 4: 3/4 = 69/31 (11), 32/68 (12); a mixture of 5 and 6: 5/6 = 62/38 (13), 33/67 (14); a mixture of 7 and 8: 7/8 = 59/41 (15), 29/71 (16)) were synthesized via combined methods consisting of acid-catalyzed alcoholysis of cellulose ethers and glycosylation of phenyl thio-cellobioside derivatives. Their surface activities in aqueous solution depended on their chemical structures: α- or β-(1→4) linkage between hydrophilic cellobiosyl and hydrophobic glucosyl blocks, methyl or ethyl groups of hydrophobic glucosyl block, and α- or β-linked ether group at the C-1 of hydrophobic glucosyl block. The mixing effect of α- and β-glycosides on surface activities was also investigated. As a result, ethyl β-D-glucopyranosyl-(1→4)-α-Dglucopyranosyl-(1→4)-2,3, 6-tri-O-ethyl-β-D-glucopyranoside 7 (G_βG _αE_β) had the highest surface activity, and its critical micellar concentration (CMC) and γ_CMC (surface tension at CMC) values of compound 7 were 0.5 mM(ca. 0.03 wt %) and 34.5 mN/m, respectively. The surface tensions of α- and β-glycoside mixtures except for compounds 9 and 10 were almost equal to those of pure compounds. The syntheses of the mixtures of α- and β-glycosides without purification process are easier than those of pure compounds. Thus, the mixtures should be more practical compounds for industrial use as a surfactant.

Full text of DOI:10.1016/j.carres.2011.04.034

Carbohydrate Research 346 (2011) 1671–1683
Contents lists available at ScienceDirect
Carbohydrate Research
journal homepage: www.elsevier.com/locate/carres
Synthesis of blockwise alkylated (1?4) linked trisaccharides as surfactants:
influence of configuration of anomeric position on their surface activities
⇑
Atsushi Nakagawa, Hiroshi Kamitakahara , Toshiyuki Takano
Graduate School of Agriculture, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan
a r t i c l e i n f o
a b s t r a c t
Article history:
New carbohydrate-based surfactants consisting of hydrophilic cellobiosyl and hydrophobic glucosyl res-
Received 4 February 2011
Received in revised form 18 April 2011
Accepted 26 April 2011
idues, methyl b-
oside 1 (GbG
methyl group), 2 (GbGbM ), 3 (GbG Mb), 4 (GbGbMb), 5 (GbG E , E: ethyl group), 6 (GbGbE ), 7 (GbG Eb),
D
-glucopyranosyl-(1?4)-
a
-D
-glucopyranosyl-(1?4)-2,3,6-tri-O-methyl-
a-D-glucopyran-
a
M
a
, G: glucopyranosyl residue,
a
and b: -(1?4)- and b-(1?4) glycosidic bonds, M:
a
a
a
a
a
a
a
Available online 4 May 2011
8 (GbGbEb) and eight a-and b-glycoside mixtures (a mixture of 1 and 2: 1/2 = 62/38 (9), 32/68 (10); a mix-
ture of 3 and 4: 3/4 = 69/31 (11), 32/68 (12); a mixture of 5 and 6: 5/6 = 62/38 (13), 33/67 (14); a mixture
of 7 and 8: 7/8 = 59/41 (15), 29/71 (16)) were synthesized via combined methods consisting of acid-cat-
alyzed alcoholysis of cellulose ethers and glycosylation of phenyl thio-cellobioside derivatives. Their sur-
Keywords:
Nonionic surfactant
Methylcellulose
Diblockco-oligomer
Surface tension
Surfactant mixtures
face activities in aqueous solution depended on their chemical structures:
hydrophilic cellobiosyl and hydrophobic glucosyl blocks, methyl or ethyl groups of hydrophobic glucosyl
block, and - or b-linked ether group at the C-1 of hydrophobic glucosyl block. The mixing effect of - and
b-glycosides on surface activities was also investigated. As a result, ethyl b- -glucopyranosyl-(1?4)-
glucopyranosyl-(1?4)-2,3,6-tri-O-ethyl-b- -glucopyranoside 7 (GbG Eb) had the highest surface activity,
and its critical micellar concentration (CMC) and cCMC (surface tension at CMC) values of compound 7
were 0.5 mM (ca. 0.03 wt %) and 34.5 mN/m, respectively. The surface tensions of - and b-glycoside mix-
tures except for compounds 9 and 10 were almost equal to those of pure compounds. The syntheses of
the mixtures of - and b-glycosides without purification process are easier than those of pure com-
a- or b-(1?4) linkage between
a
a
D
a-D-
D
a
a
a
pounds. Thus, the mixtures should be more practical compounds for industrial use as a surfactant.
Ó 2011 Elsevier Ltd. All rights reserved.
1. Introduction
of mixed surfactants is based on economical as well as synergetic
reasons.13
Nonionic carbohydrate-based surfactants such as alkylpolyglu-
cosides and polysaccharide derivatives capable of being produced
from renewable resources have recently been receiving attention
because they show good surface activities.1 It is well known that
not only the kind of hydrophilic saccharide moiety but also the
length of the hydrophobic chain influences the physicochemical
properties, such as surface activities.2 In addition, the properties
of the aqueous solutions of nonionic carbohydrate-based surfac-
The general carbohydrate-based surfactants synthesized so far
consist of sugar chains as hydrophilic block and hydrocarbon
chains as hydrophobic block. We have recently reported a novel
class of carbohydrate-based surfactants consisting of only sugar
chains in both hydrophilic and hydrophobic blocks. As a model of
methylcellulose (MC), a polydisperse mixture of diblock co-oligo-
mers of tri-O-methylated and unmodified cello-oligosaccharides
were synthesized, and their properties in aqueous solution were
investigated.14,15 Moreover, monodisperse diblock-trimer, -penta-
mer, and -hexamer,16 and ABA- and BAB-triblock hexamers of
tri-O-methylated and unmodified cello-oligosaccharides were pre-
pared to investigate relationships between their chemical struc-
ture and solubility.17 These reports suggest that monodisperse
model compounds with blocky structure along molecular chain
have higher surface activity than MC. Namely, amphiphilic diblock
trisaccharide derivatives should have a potential to act as high-per-
formance detergents.
tants are influenced by a- or b-(1?4) linkage between hydrophilic
and hydrophobic moieties.3 Carbohydrate-based surfactants hav-
ing different lengths of sugar chain and hydrocarbon chain have
been synthesized to gain detailed information about the relation-
ships between the chemical structure and their properties and to
obtain surfactants having good surface activities.4–8 The mixing ef-
fect of surfactants on their physicochemical properties has also
been reported since surfactants are used in formulations contain-
ing a mixture of different compounds.9–12 The practical utilization
Thus, diblock co-trimers of tri-O-alkylated and unmodified oli-
gosaccharides were designed to obtain surfactants with higher sur-
face activity compared to MC via novel synthetic route. For the
⇑
Corresponding author. Tel.: +81 75 753 6255; fax: +81 75 753 6300.
E-mail address: hkamitan@kais.kyoto-u.ac.jp (H. Kamitakahara).
0008-6215/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved.
doi:10.1016/j.carres.2011.04.034

1672
A. Nakagawa et al. / Carbohydrate Research 346 (2011) 1671–1683
OR'
OR
OR
purpose, the mixing effects of glycosides having
linkages between hydrophilic and hydrophobic blocks on their sur-
face activities were investigated with comparison to pure com-
a- and b-(1?4)
O
O
O
O
O
HO
RO
OR
R'O
RO
a
b
OR'
OR
OR
pounds to develop
a
facile preparation method for
a
17: R' = Me or H
18: R' = Et or H
19: R = Me
20: R = Et
21
: R = Me
22: R = Et
carbohydrate-based surfactant with high surface activity. In addi-
tion, cellulose ethers converted from abundant natural resource,
cellulose, should be used as raw materials for carbohydrate-based
surfactants from economical aspects. Hydrophobic blocks of
surfactants, methyl 2,3,6-tri-O-methyl- and ethyl 2,3,6-tri-O-
Figure 2. Synthetic route for glycosyl acceptors 21 and 22. (a)MeI or EtI/NaH/DMSO/
50 °C/2 days; (b)H2SO4/MeOH or EtOH/CHCl3/60 °C.
overall yield in 5 reaction steps, as shown in Figure 3. Compound
ethyl-D-glucopyranosides having a free hydroxyl group at C-4,
23 was converted to methyl 4,6-O-benzylidene-2,3-di-O-methyl-
were therefore prepared in a large scale by sulfuric-acid-catalyzed
alcoholysis of completely alkylated celluloses, tri-O-methyl- and
tri-O-ethyl-celluloses, respectively. Commercially available MC
(DS = 1.8) and ethylcellulose (EC, DS = 2.5) were selected to prepare
completely alkylated celluloses. Furthermore, cellobiose was
chosen as a hydrophilic block of surfactants to synthesize diblock
trimers having new hydrophilic–lipophilic balance. Here we
describe synthesis and structure–surface activity relationship of
novel diblock trisaccharide derivatives.
a-D
-glucopyranoside (25)19,20 by 4,6-O-benzylidenation and
subsequent methylation in 81.5% and 93.0% yield, respectively.
Reductive cleavage of 4,6-O-benzylidene group by BH3–THF
complex in THF and TMSOTf in CH2Cl2 afforded methyl 4-O-ben-
zyl-2,3-di-O-methyl-
Methylation of compound 26 with MeI and NaH in THF at 40 °C
gave methyl 4-O-benzyl-2,3,6-tri-O-methyl- -glucopyranoside
a-D-glucopyranoside (26) in 75.8% yield.
a-D
(27) in 93.0% yield. Removal of benzyl groups of compound 27
using 10% Pd on C in EtOH and THF under hydrogen atmosphere
at rt provided methyl 2,3,6-tri-O-methyl-
a-D-glucopyranoside
2. Results and discussion
(28)21 in quantitative yield.
In 13C NMR spectra of compounds 21 and 28, chemical shifts of
compound 21 completely correspond with those of compound 28.
Thus, the glucose derivative 21 having a free hydroxyl group at C-4
was successfully produced by sulfuric-acid-catalyzed methanolysis
of 2,3,6-tri-O-methyl-cellulose.
2.1. Syntheses of blockwise methylated or ethylated
trisaccharide derivatives 1–8
The synthetic route for blockwise methylated or ethylated
trisaccharide derivatives is illustrated in Figure 1. Phenyl 2,3,4,6-
This result prompted us to prepare ethyl 2,3,6-tri-O-ethyl-D-
tetra-O-benzyl-b-
thio-b- -glucopyranoside (30) as a glycosyl donor derived from
commercially available cellobiose was glycosylated with methyl
2,3,6-tri-O-methyl- (21) or ethyl 2,3,6-tri-O-ethyl- -glucopyrano-
D-glucopyranosyl-(1?4)-2,3,6-tri-O-benzyl-1-
glucopyranoside from industrially produced EC. As shown in
Figure 2 and 2,3,6-tri-O-ethyl-cellulose (20) was prepared from
industrially produced EC in 61.9% yield, and ethyl 2,3,6-tri-O-
D
D
ethyl-D-glucopyranoside (22) was successfully obtained by sulfu-
side (22) as glycosyl acceptors from commercially available MC
or EC, respectively. Benzyl groups of glycosylated products were
removed to give methylated or ethylated trisaccharide derivatives
1–8.
ric-acid-catalyzed ethanolysis in 95.4% yield on a gram scale.
The syntheses of glucose derivatives having a free hydroxyl
group at C-4 are required multiple reaction steps including 4,6-
O-benzylidanation and reductive cleavage of 4,6-O-benzylidene
group.22 Whereas methyl 2,3,6-tri-O-methyl-
(28) was prepared from methyl
53.3% overall yield as shown in Figure 3, the synthesis of methyl
2,3,6-tri-O-methyl- -glucopyranoside (21) from industrially pro-
a
-
D-glucopyranoside
2.1.1. Syntheses of glycosyl acceptors as hydrophobic blocks
from industrially produced MC and EC
a-D-glucopyranoside (23) in
Sulfuric-acid-catalyzed methanolysis of 2,3,6-tri-O-methyl-cel-
lulose was reported by BeMiller et al. in 1967.18 The production
D
duced MC (17) was achieved in 75.0% overall yield. Consequently,
complete alkylation of cellulose followed by sulfuric-acid-cata-
lyzed alcoholysis gave hydrophobic blocks of carbohydrate-based
surfactants effectively.
rate of methyl 2,3,6-tri-O-methyl-
D-glucopyranoside and methyl
2,3,4,6-tetra-O-methyl- -glucopyranoside was monitored as
D
a
function of depolymerization time in order to investigate the
mechanism of acid-catalyzed hydrolysis of polysaccharide. Be-
cause the completely methylated derivatives are insoluble in
water, methanolysis was applied instead of hydrolysis. As shown
in Figure 2, industrially produced MC (DS = 1.8) was completely
methylated to give 2,3,6-tri-O-methyl-cellulose (19) in 78.4% yield,
and then compound 19 was depolymerized by sulfuric-acid-cata-
lyzed methanolysis to give compound 21 in 95.6% yield on a gram
scale.
2.1.2. Synthesis of glycosyl donor as hydrophilic block
Fukase et al. reported in 1995 that glycosylation without neigh-
boring group participation in ether using phenylthio glycoside
combined by NBS and strong acid salts, LiClO4 or LiNO3 as a cata-
lyst afforded
a
-glycosides predominantly.23 On the other hand, a
combination of NBS with Ph2IOTf, Bu4NOTf, or Bu4NClO4 was
advantageous for b-selective glycosylation with 2-O-benzylated
donors by the known solvent effect of nitrile.24
Compound 28 was synthesized as an authentic compound from
commercially available methyl a-D-glucopyranoside (23) in 53.3%
OR
O
O
OBn
O
OH
O
OBn
O
HO RO
OH
OR
OH
O
O
O
BnO
BnO
BnO
SPh
HO
HO
HO
HO
HO
HO
O
RO
O
OR
O
O
RO
O
OBn
OBn
OH
OH
OH
RO
OH
OR
30
1: R = Me
2: R = Me
6: R = Et
5: R = Et
OR
O
Glycosylation
and deprotection
O
OR
OH
HO RO
OR
O
OH
OH
OR
O
O
O
HO
HO
HO
HO
OR
HO
HO
HO
O
OR
OR
O
RO
O
RO
O
O
OR
OH
OH
OH
OH
OR
21: R = Me
3: R = Me
7: R = Et
4: R = Me
8: R= Et
22: R = Et
Figure 1. Syntheses of blockwise methylated or ethylated trisaccharide derivatives 1–8.

A. Nakagawa et al. / Carbohydrate Research 346 (2011) 1671–1683
1673
OH
O
O
O
O
O
HO
HO
O
O
HO
MeO
b
a
HO
OMe
HO
MeO
OMe
OMe
23
24
25
OH
OMe
O
OMe
O
O
BnO
MeO
BnO
MeO
HO
MeO
c
e
d
MeO
OMe
MeO
MeO
OMe
OMe
26
27
28
Figure 3. Synthetic route for methyl 2,3,6-tri-O-methyl-a-D
-glucopyranoside (28). (a)Benzaldehyde dimethylacetal/p-TsOH/DMF/40 °C?80 °C/5 h/81.5%; (b)MeI/NaH/THF/rt/
6 days/93.0%; (c)BH3-THF/TMSOTf/CH2Cl2/ꢀ40?0 °C/5 h/75.8%; (d)MeI/NaH/THF/40 °C/overnight/93.0%; (e)10% Pd on C/THF/EtOH/under H2/rt/5 days/99.8%.
Thus, the phenylthio glycoside method without neighboring
group participation was selected as a glycosylation method in this
derivatives 5–8 and 13–16 were dissolved in CHCl3 to give clear
solutions. On the other hand, compounds 1–16 were soluble in
water. Chemical shifts and coupling constants of compounds 1–8
were summarized in Table 2. In the case of compounds 1, 3, 5,
study to investigate the mixing effect of
a- and b-glycosides on
surface activities. In addition, the benzyl protective groups have
the advantages of good stability to a wide range of acidic and basic
conditions and easy removal under mild hydrogenation condi-
tions25 and are suitable for purification by a preparative thin layer
chromatography (P-TLC).
and 7 having
a-(1?4) linkage between hydrophobic and hydro-
philic blocks, C-10 protons appeared at 5.40, 5.38, 5.47, and
5.44 ppm as a doublet (J = 3.9, 3.9, 3.6, and 3.9 Hz, respectively).
On the other hand, in the case of compounds 2, 4, 6, and 8 having
b-(1?4) linkage between hydrophobic and hydrophilic blocks, C-10
protons appeared at 4.40, 4.41, 4.41, and 4.41 ppm as a doublet
(J = 8.1, 7.8, 7.8, and 6.3 Hz, respectively). The C-10 protons of com-
pounds 1, 3, 5, and 7 appeared at lower magnetic field than those
Phenyl 2,3,4,6-tetra-O-benzyl-b-
D-glucopyranosyl-(1?4)-2,3,6-
tri-O-benzyl-1-thio-b-
D
-glucopyranoside (30)26 was converted
from phenyl b-D-glucopyranosyl-(1?4)-1-thio-b-D-glucopyrano-
side (29)27 as a glycosyl donor in 78.3% yield, as shown in Figure 4.
of compounds 2, 4, 6, and 8. The C-1 anomeric protons with
a con-
2.1.3. Glycosylation and debenzylation
figurations were observed at 4.97, 4.98, 5.03, and 5.01 ppm as a
doublet (J = 3.3, 3.6, 3.6, and 3.3 Hz, respectively), whereas those
with b configurations appeared at 4.40, 4.40, 4.46, and 4.44 ppm
as a doublet (J = 7.8, 7.5, 8.4, and 8.1 Hz, respectively). The C-1 pro-
tons of compounds 1, 3, 5, and 7 appeared at lower magnetic field
Figure 5 shows synthetic route for blockwise alkylated trisac-
charide derivatives 1–16. The glycosylation, purification of glycos-
ylated products by P-TLC, and removal of benzyl groups as
temporary protective groups gave final products. Glycosylation of
donor 30 with acceptors 21 or 22 using NBS and AgOTf under high
vacuum condition28,29 gave crude glycosylated products in 55–62%
yields (see Table 1). In the case of glycosylation reactions in CH2Cl2,
than those of compounds 2, 4, 6, and 8. The C-1a carbons of com-
pounds 1, 2, 5, and 6 appeared at 99.2, 99.2, 98.3, and 98.5 ppm,
respectively, whereas the C-1b carbons of compounds 3, 4, 7, and
8 appeared at 105.7, 105.6, 104.5, and 104.7 ppm, respectively.
The C-10a carbons of compounds 1, 3, 5, and 7 appeared at 100.7,
100.5, 100.4, and 99.6 ppm, respectively, whereas the C-10b car-
bons of compounds of 2, 4, 6, and 8 appeared at 105.0, 104.9,
104.7, and 105.2 ppm, respectively. The C-100b carbons derived
from cellobiose blocks of compounds 1–8 appeared at ca. 105 ppm.
The optical rotations of compounds 1–16 measured in water
were summarized in Table 3. In the case of pure compounds 1–8,
the ratio of
ble 1, entry 1:
ation reaction in EtCN afforded b-glycosides with moderate stereo-
selectivity (Table 1, entry 3: /b = 18/39, entry 4: /b = 18/38). The
-glycosides 31–34 having an axial substituent group at C-1 were
a-glycosides was higher than that of b-glycosides (Ta-
a
/b = 35/20, entry 2: /b = 38/24), whereas glycosyl-
a
a
a
a
easily isolated by P-TLC from the b-glycosides 35–38 having an
equatorial substituent group, because Rf values were different each
other (see Section 4). In order to investigate a mixing effect of
and b-glycosides on surface activities, it is indispensable to know
each surface activity of pure - and b-glycosides. Thus, compounds
a-
the optical rotations of compounds having
a-(1?4) linkage be-
a
tween hydrophilic cellobiosyl and hydrophobic glucosyl blocks
were higher than those of compounds having b-(1?4) linkage:
+59.1° (1: GbG M ) > +37.9° (2: GbGbM ); +32.0° (3:
39, 40, 43 and 44 were purified from compounds 31, 32, 33 and 34,
respectively. In the same way, compounds 41, 42, 45, and 46 were
obtained from compounds 35, 36, 37, and 38, respectively.
a
a
a
GbG Mb) > ꢀ15.9° (4: GbGbMb); +56.0° (5: GbG E ) > +51.0° (6:
a
a a
Although Rf values between
a-glycosides 39, 41, 43, and 45 and
GbGbE ); +28.6° (7: GbG Eb) > ꢀ2.9° (8: GbGbEb). In addition, the
a
a
b-glycosides, 40, 42, 44, and 46 were close, respectively, six-
optical rotations of compounds having a-glycosidic bond at C-1
times-purification-process on P-TLC plate (eluent; EtOAc/n-hexane
were higher than those of compounds having b-linkage: +59.1°
1:4) gave pure a- and b-glycosides 39–46. Benzyl groups of trisac-
(1: GbG M ) > +32.0° (3: GbG Mb); +37.9° (2: GbGbM ) > ꢀ15.9°
a
a
a
a
charide derivatives 31–46 were removed by 20% Pd(OH)2 on C in
EtOH and THF under hydrogen atmosphere at rt to give desired
blockwise alkylated trisaccharide derivatives 1–16.
(4: GbGbMb); +56.0° (5: GbG E ) > +28.6° (7: GbG Eb); +51.0° (6:
a a a
GbGbE ) > ꢀ2.9° (8: GbGbEb). The optical rotations of mixtures 9,
a
10, and 13 were higher than those of pure compounds, whereas
the optical rotation values of compounds 11, 12, 14, 15, and 16
2.1.4. Solubilities and chemical structures of compounds 1–16
Solubilities of compounds 1–16 in CHCl3 and water were inves-
tigated. Methylated derivatives 1–4 and 9–12 were not completely
soluble in CHCl3 at concentration of 1.0 wt %, whereas ethylated
were in between pure a- and b-glycosides.
2.2. Surface activities of blockwise methylated or ethylated
trisaccharide derivatives 1–16
The influence of chemical structure of blockwise alkylated tri-
saccharides 1–8 on the surface tension of their aqueous solutions
was investigated. The differences of surface tension between 1
OH
OH
O
OBn
OBn
O
O
O
BnO
HO
HO
HO
O
BnO
BnO
SPh
SPh
O
(GbG M ) and 2 (GbGbM ), between 3 (GbG E ) and 4 (GbGbE ), be-
a
a
a
a a
a
OH
a
OBn
OH
OBn
tween 5 (GbG Mb) and 6 (GbGbMb), and between 7 (GbG Eb) and 8
a
a
30
29
(GbGbEb) would reveal the influence of
a
- or b-(1?4) linkage be-
Figure 4. Synthesis of glycosyl donor 30. (a)BnBr/NaH/TBNI/THF/DMF/80 °C/6 h.
tween hydrophilic cellobiosyl and hydrophobic glucosyl blocks

1674
A. Nakagawa et al. / Carbohydrate Research 346 (2011) 1671–1683
α / β
OH
OH
O
OR
O
O
HO
HO
HO
O
O
RO
OH
OH
RO
OR
9: R = Me, α > β; 10: R = Me, α < β
13: R = Et, α > β; 14: R = Et, α < β
OR
OR
O
O
O
O
HO RO
OH
OBn
BnO RO
b
O
O
HO
HO
HO
RO
BnO
BnO
BnO
RO
OR
OR
α / β
O
O
O
O
b
b
OBn
O
OBn
OR
OH
OBn
OH
OBn
OBn
O
OBn
O
BnO
BnO
BnO
O
O
1: R = Me; 5: R = Et
39: R = Me; 43: R = Et
BnO
BnO
BnO
SPh
O
RO
O
O
*
*
OBn
OBn
RO
OH
OBn OBn
OR
OH
OR
OBn
OBn
OR
O
O
O
O
BnO
BnO
BnO
O
HO
HO
HO
O
31: R = Me, α > β; 32: R = Me, α < β
33: R = Et, α > β; 34: R = Et, α < β
O
RO
O
RO
O
O
30
OBn
OH
OH
RO
OR
OBn
RO
OR
2: R = Me; 6: R = Et
40: R = Me; 44: R = Et
OR
OR
O
O
O
O
OR
HO RO
OH
a
BnO RO
OR
OBn
*
O
O
HO
HO
HO
OR
BnO
BnO
BnO
OR
O
α / β
O
O
O
b
b
OH
OBn
O
OBn
OH
OBn
OR
OBn
OR
O
O
BnO
BnO
BnO
O
3: R = Me; 7: R = Et
O
41: R = Me; 45: R = Et
OR
HO
RO
O
RO
OR
OH
OBn
OH
OR
OBn
OBn
OR
OBn
OR
OR
O
O
O
O
HO
HO
HO
O
BnO
BnO
BnO
O
OR
OR
35: R = Me, α > β; 36: R = Me, α < β
37: R = Et, α > β; 38: R = Et, α < β
O
RO
O
RO
O
21: R = Me; 22: R = Et
O
OH
OBn
OH
OR
OBn
OR
4: R = Me; 8: R= Et
42: R = Me; 46: R = Et
b
α / β
OH
OH
O
OR
O
O
HO
HO
HO
O
OR
O
RO
OH
OH
OR
11: R = Me, α > β; 12: R = Me, α < β
15: R = Et, α > β; 16: R = Et, α < β
Figure 5. Synthetic routes for blockwise methylated or ethylated trisaccharide derivatives 1–16. (a)NBS/AgOTf/MS 3 Å or MS 4 Å/EtCN or CH2Cl2/rt/under vacuum, (b)Pd(OH)2
on C/THF/EtOH/under H2/rt. ⁄Purification by a preparative thin layer chromatography (P-TLC).
Table 1
Glycosylation of phenyl thio-cellobioside derivative 30 with acceptors 21or 22
Entry
Donor
Acceptor
Substituent group (R)
Solvent
Yield (%)
Total
GbG R
GbG Rb
GbGbR
a
GbGbRb
a
a
a
1
2
3
4
30
30
30
30
21
22
21
22
Me
Et
Me
Et
CH2Cl2
CH2Cl2
EtCN
55
62
57
56
26
28
12
14
9
10
6
16
17
26
28
4
7
13
10
EtCN
4
Donor (1.0 equiv) and acceptor (1.5 equiv) were used for glycosylation. The glycosylation reaction was carried out at rt for 24 h.
CH2Cl2: dichloromethane, EtCN: propionitrile.
on surface activities. The differences of surface tensions between
1and 5, between 2 and 6, between 3 and 7, and between 4 and 8
would reveal the influence of methyl or ethyl group as substituent
group of hydrophobic block on their surface activities. The differ-
ences of surface tension between 1 and 3, between 2 and 4, be-
tween 5 and 7, and between 6 and 8 would reveal the influence
1. The glycosides having a-(1?4) linkage between hydrophilic
cellobiosyl and hydrophobic glucosyl blocks are more surface
active than those having b-(1?4) linkage.
2. The glycosides having ethyl groups have higher surface activity
than those having methyl groups.
3. b-Glycosides have higher surface activity than a-glycosides.
of a- and b-linkages at C-1 on their surface activities.
The above-mentioned 1, 2, and 3 are separately discussed in
Figures 7–9 in the following sections.
2.2.1. Surface activities of pure compounds 1–8
Surface tensions were measured in the range of 0.01–10 wt %
concentration. Surface tensions of compounds 1–8 and industrially
produced MC in aqueous solution decreased with increasing con-
centration, as shown in Figure 6. Surface activities of pure com-
pounds 1–8 depended upon their chemical structures and ranked
as follows: 7 > (3 ; 5 ; 8) > (1 ; 4 ; 6) > 2 (Fig. 6). Among pure
2.2.1.1. Influence of
hydrophobic blocks on surface activities of compounds 1–
8. The surface tensions of the glycosides having -(1?4) link-
age between hydrophilic cellobiosyl and hydrophobic glucosyl
blocks were compared with those of the glycosides having b-
(1?4) linkage. The differences of surface tension between 1
a- and b-linkages between hydrophilic and
a
compounds, compounds 7 (GbG Eb) and 2 (GbGbM ) had highest
a
a
and lowest surface activity, respectively. The surface tensions of
blockwise methylated trisaccharide derivatives 1–4 decreased
with increasing concentrations even over 0.1 wt % concentration
which was CMC of MC (SM-4). The surface tensions of compounds
1–4 were lower than that of MC at 0.5 wt % concentration. These
facts indicate that blockwise methylated trisaccharides have abili-
ties to decrease surface tensions over CMC of MC. The surface ten-
sions of compounds 1–8 showed three trends as follows:
(GbG M ) and 2 (GbGbM ), between 3 (GbG Mb) and 4 (GbGbMb),
a a a a
between 5 (GbG E ) and 6 (GbGbE ), and between 7 (GbG Eb) and
a a
a
a
8 (GbGbEb) shown in Figure 7a–d indicate that
a
-glycosides have
higher surface activities than b-glycosides. It is likely that a-glyco-
sides are more hydrophobic than b-glycosides.30 Dupuy et al. re-
ported in 1997 that the glycosides having different configuration
at anomeric center,
a-1-n-dodecyl-D-maltoside and b-1-n-dode-
cyl-D
-maltoside, formed different micellar aggregates in water.31

A. Nakagawa et al. / Carbohydrate Research 346 (2011) 1671–1683
1675
The difference suggests that the configuration of the head group
affects the orientation of the polar residue and hence the packing
of monomers during self-assembly. Consequently, in the case of
blockwise alkylated trisaccharides 1–8, a- and b-glycosides in this
study should form different micellar aggregates in water, and as a
result, had different surface activities.
2.2.1.2. Influence of methyl or ethyl group on surface activities
of compounds 1–8.
In general, surface activity of a surfactant
in an aqueous solution increases with increasing number of carbon
atoms in the hydrophobic moiety.4 The differences of surface ten-
sion between 1 (GbG M ) and 5 (GbG E ), between 2 (GbGbM ) and
a a
a
a
a
6 (GbGbE ), between 3 (GbG Mb) and 7 (GbG Eb), and between 4
a
a
a
(GbGbMb) and 8 (GbGbEb) shown in Figure 8 indicate that the glyco-
sides having ethyl groups had higher surface activities than those
having methyl groups, as expected.
2.2.1.3. Influence of
compounds 1–8.
a
- and b-glycosides on surface activities of
Similar to the influence of - and b-linkage
a
between hydrophilic and hydrophobic blocks on surface tension,
compounds 1, 2, 5, and 6 having -glycosidic bond at C-1 were ex-
a
pected to have higher surface activities than those having b-link-
age.31,32 However, it was unexpectedly found that b-glycosides 3,
4, 7, and 8 had higher surface activities than
a-glycosides, resulting
from the differences of surface tension between 1 (GbG M ) and 3
a
a
(GbG Mb), between 2 (GbGbM ) and 4 (GbGbMb), between 5
a
a
(GbG E ) and 7 (GbG Eb), and between 6 (GbGbE ) and 8 (GbGbEb),
a a
a
a
as shown in Figure 9.
2.2.2. Surface activities of
a
- and b-glycoside mixtures 9–16
The surface tensions of mixtures 9–16 were measured to know
mixing effects of glycosides having - and b-(1?4) linkages be-
tween hydrophilic cellobiosyl and hydrophobic glucosyl blocks
on their surface activities. The /b ratios of compounds 9–16 are
summarized in Table 3. Compounds 9, 11, 13, and 15 are -rich,
a
a
a
and compounds 10, 12, 14, and 16 are b-rich. The surface tension
curves of pure and mixed compounds were similar to each other,
as shown in Figure 10. Interestingly, compounds 9 and 10 had
higher surface activities than pure compounds 1 and 2 at all range
of concentration tested. A special mixing effect was found in the
case of mixtures 9 and 10. The surface tensions of mixtures 11–
16 roughly followed the additivity rule. The surface tensions of
compounds 11, 13, 14, 15 and 16 were lower than those of pure
compounds below 0.2 mg/mL concentration, whereas the surface
activities of compounds 11, 13, 14, 15 and 16 were approximately
the average of those of the two pure compounds above 0.2 mg/mL
concentration.
2.2.3. Comparisons of surface activity of blockwise alkylated
trisaccharide derivatives with those of other commercially
available surfactants
The surface activities of compounds 1–16 were compared with
those of commonly-used surfactants, MC (Methocel Premium A15,
mean molecular weight 14 kDa, methyl substitution between
27.5% and 31.5%),33 n-octyl b- -glucoside,34 dodecyloctaethylen-
D
glycol (C12E8),35 sodium dodecyl sulfate (SDS),36 n-dodecyl b-
D-
maltoside,37 cetyltrimethylammonium bromide (CTAB),36 polyeth-
ylene glycol p-(1,1,3,3-tetramethylbutyl)-phenyl ether (Triton X-
100),38 as shown in Table 4. In general, cCMC (surface tension at
CMC) is the minimum value of surface tension. The CMC value
and cCMC of compound 7 (GbG Eb) which show the highest surface
a
activity among pure compounds 1–8 were 0.5 mM (ca. 0.03 wt %)
and 34.5 mN/m, respectively. These values were almost same or
better compared with other surfactants in Table 4. The CMC values
and cCMC of compound 7 were lower than those of MC, indicating
that the surface activity of compound 7 is superior to that of MC.

1676
A. Nakagawa et al. / Carbohydrate Research 346 (2011) 1671–1683
Table 3
Optical rotations of compounds 1–16
Mixture
a
/b ratio calculated by
Optical rotations
Optical rotations of mixtures
Optical rotations of pure compounds
1H NMR
aa
ba
9
10
1/2 = 62/38
1/2 = 32/68
—
—
+83.7°
+67.7°
+59.1° (1: GbG M )
+37.9° (2: GbGbM )
a
a
a
11
12
3/4 = 62/38
3/4 = 33/67
3/4 = 62/38
3/4 = 41/59
+16.7°
+3.9°
+32.0° (3: GbG Mb)
ꢀ15.9° (4: GbGbMb)
a
13
14
5/6 = 69/31
5/6 = 32/68
—
+68.4°
+51.7°
+56.0° (5: GbG E )
+51.0° (6: GbGbE )
a
a
a
5/6 = 32/68
15
16
7/8 = 59/41
7/8 = 29/71
7/8 = 82/18
7/8 = 17/83
+22.8°
+2.5°
+28.6° (7: GbG Eb)
ꢀ2.9° (8: GbG Mb)
a
a
a
a- or b-glycosides having a- or b-(1?4)-linkage between hydrophilic cellobiosyl and hydrophobic glucosyl block.
tween hydrophilic cellobiosyl and hydrophobic glucosyl blocks
were almost equal to those of pure compounds except for com-
pounds 9 and 10. Taking the practical use into account, the synthe-
ses and following utilization of
a- and b-anomer mixtures as a
surfactant were easier than those of pure compounds. Carbohy-
drate-based surfactants consisting of only sugar chains in both
hydrophilic and hydrophobic blocks had almost equal surface
activities to other commercially available surfactants. In addition,
these findings will contribute to novel utilization of MC and EC.
4. Experimental details
4.1. Materials and measurements
4.1.1. Materials
SM-4 (methoxyl content: 29.2%; DS = 1.76; viscosity of 2% aque-
ous solution: 4.08 mPa s; Mw = 2.5 ꢁ 104) and SM-400 (methoxyl
content: 27.5–31.5%; viscosity of 2% aqueous solution: 400 mPa s)
were kindly provided by Shinetsu Chemical, Japan. Ethyl cellulose
(abt. 49% ethoxy content) was purchased from Wako Pure Chemi-
cal Industries, Ltd. The products were purified on silica gel column
chromatography (Wakogel C-200, Wako Pure Chemical Industries
Figure 6. Surface tension–concentration curves of blockwise methylated or ethy-
lated trisaccharide derivatives and SM-4. d: compound 1; s: compound 2; N:
compound 3; 4: compound 4; j: compound 5; h: compound 6; ꢀ: compound 7; }:
compound 8; ꢁ: SM-4.
3. Conclusions
or Silica Gel 60N [spherical, neutral], 100–210 lm, Kanto Chemical
Co., Inc.) or thin layer chromatography (Silica Gel 60 F254, 0.5 mm
or 2 mm thickness, Merck, Germany).
A synthetic method for blockwise alkylated trisaccharides from
cellobiose and commercial cellulose derivatives, was established.
Glucose derivatives having a free hydroxyl group at C-4 were pre-
pared from MC and EC by sulfuric-acid-catalyzed alcoholysis on a
gram scale. Glycosylation of benzylated thio-cellobioside with
such glucose derivatives successfully afforded blockwise alkylated
trisaccharide derivatives as a new class of carbohydrate-based sur-
factant. The blockwise ethylated trisaccharides were for the first
time synthesized. The surface tension measurements of blockwise
alkylated trisaccharide derivatives revealed the following three
influences of their chemical structures on surface activity:
4.1.2. General measurements
1H and 13C NMR spectra were recorded with a Varian Inova 300
FT-NMR (300 MHz) spectrometer in chloroform-d with tetrameth-
ylsilane as an internal standard or in deuterium oxide with 3-(tri-
methylsilyl)-1-propanesulfonicacid sodium salt as an external
standard. Proton and carbon resonances were assigned by two-
dimensional NMR experiments (gCOSY, TOCSY, gHSQC, and
gHMBC). Chemical shifts (d) and coupling constants (J) are given
in d-values (ppm) and Hertz, respectively. Matrix assisted laser
desorption/ionization time-of-flight mass (MALDI-TOF MS) spectra
were recorded with a Bruker MALDI-TOF MS REFLEX III in the po-
sitive ion and reflector modes. For ionization, a nitrogen laser was
used. All spectra were measured in the reflector mode using exter-
nal calibration. MALDI-TOF MS spectra of compounds were mea-
sured with 2,5-dihydroxybenzoic acid (DHB) as a matrix. A
Shimadzu SEC system (CBM-10A, SPD-10A, SIL-10A, LC-10AT,
FCV-10AL, CTO-10A, RID-10A, and FRC-10, Shimadzu, Japan) and
Shodex columns (K802, K802.5, and K805) were used. Number
and weight averaged molecular weights (Mn, Mw) and polydisper-
sity indices (Mw/Mn) were estimated using polystyrene standards
(Shodex). A flowrate of 1 mL /min at 40 °C was chosen. Optical
rotations were measured using a JASCO Dip-1000 digital polarim-
eter. Melting points was determined on a FP900 Thermosystem
(Mettler Toledo) with FP82 Microscope HotStage.
1. The type of linkage,
cellobiosyl and hydrophobic glucosyl blocks, influences surface
activity: -glycosides are more surface active than b-glycosides.
a- or b-(1?4) linkage between hydrophilic
a
2. The ethyl derivatives have higher surface activity than methyl
derivatives.
3. The compounds having b-glycosidic bond at C-1 have higher
surface activity than those having
a-glycosidic bond.
Consequently, among pure compounds, compounds 7 (GbG Eb)
a
and 2 (GbGbM showed highest and lowest surface activities,
a
respectively. Thus, important structural factors for a surfactant
with high activity were found, resulting from the detailed
investigation on the chemical structure–surface activity relation-
ships of blockwise alkylated trisaccharides. The surface activities
of mixtures of the glycosides having
a- and b-(1?4) linkages be-

A. Nakagawa et al. / Carbohydrate Research 346 (2011) 1671–1683
1677
Figure 7. Surface tension–concentration curves of pure compounds 1–8: the effect of
a- and b-(1?4) linkages between hydrophobic and hydrophilic moieties on surface
activity; d: compound 1; s: compound 2; N: compound 3; 4: compound 4; j: compound 5; h: compound 6; ꢀ: compound 7; }: compound 8.
4.1.3. Surface tension measurements
4.2.2. 2,3,6-Tri-O-ethyl-cellulose (20)
Compounds were dissolved in water at various concentrations
and the values of their surface tension were measured by the Wil-
helmy method using a CBVP-A3 surface tensiometer (Kyowa Inter-
face Science, Co. Ltd, Tokyo) at 20 °C. The values were used when
the values were stable after 30 min. The surface tension of distilled
water is 72.8 mN/m at 20 °C.
To a solution of EC (18) (DS = 2.5, 10.6095 g, 0.045 mol) in
DMSO (140 mL), NaH (60% in mineral oil, 1.75 g, 0.043 mol,
1.0 equiv per anhydroglucopyranose) was added at 0 °C. The reac-
tion mixture was stirred for 4 h at 50 °C. Then EtI (3.45 mL,
0.043 mmol, 1.0 equiv per anhydroglucopyranose unit) was added
into the solution. The reaction mixture was stirred at 50 °C for
6 days. MeOH (3.0 mL) was added to the reaction mixture, and
the mixture was poured slowly into water (3.0 L). The resulting
precipitates were washed with water for three times and MeOH
twice, centrifuged (12,000 rpm/10 min/2 °C), concentrated to dry-
ness to give compound 20 (6.57 g, 61.9% yield).
4.2. Syntheses of blockwise methylated or ethylated
trisaccharide derivatives
4.2.1. 2,3,6-Tri-O-methyl-cellulose (19)
To a solution of MC (17) (SM-400, DS = 1.8, 3.03 g, 0.016 mol)
in DMSO (230 mL), NaH (60% in mineral oil, 2.6 g, 0.064 mol,
4.0 equiv per anhydroglucopyranose) was added at 0 °C. The
reaction mixture was stirred at 50 °C overnight. Then MeI
(4.0 mL, 0.064 mol, 4.0 equiv per anhydroglucopyranose) was
added into the solution. The reaction mixture was stirred at
50 °C for 24 h. MeOH (5.5 mL) was added to the reaction mix-
ture, and then the mixture was poured slowly into water
(3.0 L). The resulting precipitates were washed with water for
three times and EtOH twice, centrifuged (12,000 rpm/10 min/
2 °C), and concentrated to dryness to give compound 19
(2.587 g, 78.4% yield).
1H NMR (CDCl3): d 1.14, 1.14, 1.16 (–CH3), 3.02 (H-2), 3.16–3.25
(H-3, H-5), 3.39–4.07 (–CH2–), 3.52 (H-6), 3.73 (H-4), 4.33 (H-1);
13C NMR (CDCl3): d 15.2, 15.5, 15.6 (–CH3), 66.3 (C-6), 68.2, 68.3
(–CH2–), 75.1 (C-5), 77.2 (C-4), 81.7 (C-2), 83.4 (C-3), 102.8 (C-1).
Mp 185–186 °C. ½a D21:0
ꢂ
+7.7 (c 0.913, CHCl3). Mn = 1.17 ꢁ 104,
Mw = 2.45 ꢁ 104, Mw/Mn = 2.09, DPn = 47.5, DPw = 99.5.
4.2.3. Methyl 2,3,6-tri-O-methyl-D-glucopyranoside (21)
To a solution of compound 19 (105.2 mg, 0.5156 mol) in CHCl3
and MeOH (5 mL, 4:1, v/v), concentrated sulfuric acid and MeOH
(5 mL, 1:4, v/v) were added at 0 °C. The reaction mixture was stir-
red at 60 °C for 9 h. The solution was neutralized with NaHCO3. The
salts were filtered off and washed with EtOAc. The combined fil-
trate and washings were concentrated to dryness to give com-
1H NMR (CDCl3): d 2.96 (H-2), 3.22 (H-3), 3.31 (H-5), 3.39 (C6–
OCH3), 3.62–3.66 (H-6a), 3.69 (H-4), 3.72–3.81 (H-6b), 4.33 (H-1);
13C NMR (CDCl3): d 59.1(C6–OCH3), 60.3 (C2–OCH3), 60.5 (C3–
OCH3), 70.2 (C-6), 74.8 (C-5), 77.1 (C-4), 83.4 (C-2), 84.9 (C-3),
pound 21 (114.8 mg, 95.6% yield,
a/b = 75/25).
1H NMR (CDCl3): d 3.01 (dd, 1H, J = 7.5, J2,3 = 7.8, H-2b), 3.13 (t,
103.1 (C-1). Mp 208–209 °C.
½
a 2D0:0
ꢂ
ꢀ7.8 (c 0.937, CHCl3).
1H, J = 8.7, J3,4 = 9.0, H-3b), 3.25 (dd, 1H, J = 3.6, J2,3 = 3.6, H-2
3.39–3.73 (10H, H-3 , H-4 , H-5 , H-6
OCH3), 4.20 (d, 1H, J1,2 = 7.5, H-1b), 4.86 (d, 1H, J1,2 = 3.6, H-1
a
),
Mn = 2.04 ꢁ 104, Mw = 4.82 ꢁ 104, Mw/Mn = 2.36, DPn = 100.0,
DPw = 236.2.
a
a
a
a, H-4b, H-5b, H-6b, –
a);

1678
A. Nakagawa et al. / Carbohydrate Research 346 (2011) 1671–1683
Figure 8. Surface tension–concentration curves of pure compounds 1–8: the effect of methyl or ethyl group on surface activity; d: compound 1; s: compound 2; N:
compound 3; 4: compound 4; j: compound 5; h: compound 6; ꢀ: compound 7; }: compound 8.
13C NMR (CDCl3): d 54.9, 56.7, 58.2, 59.1, 59.3, 59.9, 60.5, 60.8 (–
of MeOH (2 mL). The reaction mixture was diluted with EtOAc,
washed with water and brine, dried over Na2SO4, and concentrated
to dryness to give crude product 25 (11.715 g, 93.0% yield).
To a solution of compound 25 (5.0054 g, 16.128 mmol) in anhy-
drous CH2Cl2 (6 mL), BH3–THF complex in THF (59 mL, 0.6164 mol,
38.5 equiv) were added at ꢀ41 °C. After 1 h, TMSOTf (1.7 mL,
9.6718 mmol, 0.6 equiv) was added to the reaction mixture at
ꢀ41 °C. The temperature of the reaction mixture was gradually
raised up to 0 °C in 2 h and the mixture was kept at 0 °C for
4.5 h. The mixture was cooled under ꢀ40 °C and then, Et3N
(16.4 mL) was added to the solution. Next, MeOH was added to
the solution until hydrogen was not produced. The mixture was di-
luted with EtOAc, washed with 4 M-HCl, saturated aq NaHCO3 and
brine, dried over Na2SO4, and concentrated to dryness to give crude
crystals. The crude compound was purified by silica gel column
chromatography eluted with CH2Cl2 to give compound 26
(3.8225 g, 75.8% yield).
OCH3), 69.7 (C-4
a
a
), 69.8 (C-5
), 83.1, 85.6, 97.2 (C-1
a), 70.3, 71.5 (C-6a), 72.0, 73.9, 81.4
(C-2 ), 82.7 (C-3
a
a
), 104.1 (C-1b). ½a D18:7
ꢂ
+102.8 (c 0.997, CHCl3).
4.2.4. Ethyl 2,3,6-tri-O-ethyl-D-glucopyranoside (22)
To a solution of compound 20 (504.7 mg, 2.051 mmol) in CHCl3
and EtOH (25 mL, 4:1, v/v), concentrated sulfuric acid and EtOH
(25 mL, 1:4, v/v) were added at 0 °C. The reaction mixture was stir-
red at 60 °C for 21 h. The solution was neutralized with NaHCO3.
The salts were filtered off and washed with EtOAc. The combined
filtrate and washings were concentrated to dryness to give com-
pound 22 (481.5 mg, 95.4% yield, a/b = 67/33).
1H NMR (CDCl3): d 1.17–1.28 (–CH3), 3.05 (dd, 1H, J = 7.2,
J2,3 = 9.6, H-2b), 3.21 (t, 1H, J = 9.0, J3,4 = 8.7, H-3b), 3.32 (dd, 1H,
J = 3.6, J2,3 = 3.6, H-2
H-5b, H-6b, –CH2–), 4.29 (d, 1H, J1,2 = 7.2, H-1b), 4.93 (d, 1H,
J1,2 = 3.6, H1
); 13C NMR (CDCl3): d 14.8, 15.0, 15.1, 15.5, 15.6,
a), 3.39–4.01 (H-3a, H-4a, H-5a, H-6a, H-4b,
a
1H NMR (CDCl3): d 3.21 (dd, 1H, J1,2 = 4.0, H-2), 3.37 (s, 3H, C1–
OCH3), 3.45 (t, 1H, J = 9.0, J = 10, H-4), 3.49 (s, 3H, C2–OCH3), 3.58–
3.63 (5H, H-3, H-5, C3–OCH3), 3.69–3.80 (2H, J = 4.5, J = 4.0, J = 2.5,
J = 2.5, H-6), 4.65 (1H, J = 11, CH2Ph), 4.80 (d, J1,2 = 4.0, H-1), 4.85
(1H, J = 11, CH2Ph), 7.25–7.35 (5H, aromatic H); 13C NMR (CDCl3):
d 54.6 (C1–OCH3), 58.4 (C2–OCH3), 60.5 (C3–OCH3), 61.0 (C-6),
70.4 (C-5), 74.4 (–CH2Ph), 76.9 (C-4), 81.5 (C-2), 83.1 (C-3), 96.9
(C-1), 127.3–138 (aromatic C).
15.8 (–CH3), 63.1, 65.5, 66.3, 67.0, 67.1, 68.1, 68.5, 68.6, 69.5,
70.0, 70.9, 71.1, 71.9, 72.6, 73.4, 80.1, 80.8, 81.7, 83.9, 96.4 (C-
1a
), 103.3 (C-1b). ½a D19:7
ꢂ
+50.4 (c 1.038, CHCl3).
4.2.5. Methyl 4-O-benzyl-2,3-di-O-methyl-
a-
D-glucopyranoside
(26)
To a solution of methyl 4,6-O-benzylidene-a-D-glucopyranoside
(24) (10.0822 g, 0.035 mol) in THF (75 mL), NaH (60% in mineral
oil, 2.2158 g, 0.055 mol, 1.5 equiv) and MeI (3.3 mL, 1.5 equiv)
were added at 0 °C. The reaction mixture was stirred at rt over-
night. Then NaH (1.4349 g, 0.035 mol, 1.0 equiv) and MeI (2.2 mL,
1.0 equiv) were added into the solution. The reaction mixture
was stirred at rt for 5 days. The reaction was quenched by addition
4.2.6. Methyl 4-O-benzyl-2,3,6-tri-O-methyl-a-D-
glucopyranoside (27)
To a solution of compound 26 (3.8225 g, 12.24 mmol) in THF
(30 mL), NaH (60% in mineral oil, 0.5960 g, 14.9 mmol, 1.2 equiv)
and MeI (0.91 mL, 14.6 mmol, 1.2 equiv) were added at 0 °C. After

A. Nakagawa et al. / Carbohydrate Research 346 (2011) 1671–1683
1679
Figure 9. Surface tension–concentration curves of pure compounds 1–8: the effect of
compound 3; 4: compound 4; j: compound 5; h: compound 6; ꢀ: compound 7; }: compound 8.
a- and b-linkages at C-1 on surface activity; d: compound 1; s: compound 2; N:
3 h, NaH (60% in mineral oil, 0.1590 g, 3.975 mmol, 0.3 equiv) and
MeI (0.23 mL, 3.694 mmol, 0.3 equiv) were added into the solution.
The reaction mixture was stirred at rt overnight. The reaction was
quenched by addition of MeOH (0.75 mL). The reaction mixture
was diluted with EtOAc, washed with water and brine, dried over
Na2SO4, and concentrated to dryness to give crude products. The
compound was purified by silica gel column chromatography
eluted with CH2Cl2to give compound 27 (3.7077 g, 93.0% yield).
1H NMR (CDCl3): d 3.26 (dd, 1H, J = 3.6, J2,3 = 3.6, H-2), 3.35 (s,
3H, C6–OCH3), 3.39 (s, 3H, C1–OCH3), 3.47–3.51 (4H, H-4, C2–
OCH3), 3.52–3.60 (3H, H-3, H-6), 3.63 (s, 3H, C3–OCH3), 3.67 (m,
1H, H-5), 4.60 (d, 1H, J = 11, CH2Ph), 4.86 (d, 1H, J = 11, CH2Ph),
7.27–7.35 (5H, aromatic H); 13C NMR (CDCl3): d 54.7 (C1–OCH3),
58.5 (C2–OCH3), 58.8 (C6–OCH3), 60.6 (C3–OCH3), 69.4 (C-5), 70.5
(C-6), 74.5 (–CH2Ph), 77.0 (C-4), 81.5 (C-2), 83.3 (C-3), 97.1 (C-1),
127.3, 127.6, 128.0, 138.0 (aromatic C).
(C6–OCH3), 60.9 (C3–OCH3), 69.6 (C-4), 69.9 (C-5), 71.5 (C-6),
81.4 (C-2), 82.7 (C-3), 97.2 (C-1).
4.2.8. Phenyl 2,3,4,6-tetra-O-benzyl-b-D-glucopyranosyl-(1?4)-
2,3,6-tri-J-benzyl-1-thio-b-
D
-glucopyranoside (30)
-glucopyranosyl-(1?4)-1-thio-b-D-
To a solution of phenyl b-
D
glucopyranoside 29 (0.9263 g, 2.1320 mmol) in THF (20 mL) and
DMF (5 mL), NaH (1.1939 g, 29.848 mmol, 60% in mineral oil)
and tetra-n-butyl ammonium iodide (114.5 mg, 0.309 mmol) were
added and then BnBr (3.6 mL, 30.268 mmol) was added slowly
dropwise at 0 °C. The reaction mixture was stirred for 6 h at
80 °C. MeOH (1.8 mL) was added to the reaction mixture for the
decomposition of excess BnBr. The reaction mixture was diluted
with EtOAc, washed with saturated aq NaHCO3 and brine, dried
over Na2SO4, and concentrated to dryness to give slightly yellow
crystals. The crude crystals were recrystallized from EtOH to give
colorless crystals 30 (1.778 g, 78.3% yield).
4.2.7. Methyl 2,3,6-tri-O-methyl-
a-
D
-glucopyranoside (28)
1H NMR (CDCl3): d 3.30–3.47 (4H, H-20, H-40, H-5), 3.44 (t, 1H,
J = 9.6, J2,3 = 9.0, H-2), 3.53–3.76 (5H, H-3, H-30, H-50, H-60), 3.84
(d, J = 4.2, H-6), 4.03 (t, 1H, J3,4 = 9.6, J4,5 = 9.6, H-4), 4.49 (d, 1H,
To a solution of compound 27 (1.7282 g, 5.2953 mmol) in THF
(5 mL) and EtOH (5 mL), 10% Pd on C (0.9886 g) was added at rt.
The reaction mixture was stirred at rt under hydrogen atmosphere
overnight. Then 10% Pd on C (0.5099 g) was added into the solu-
tion. The 10% Pd on C was filtered off and washed 20% MeOH/
CH2Cl2 (v/v) and MeOH. The combined washings and filtrate were
concentrated to give compound 28 (1.249 g, 99.8%).
J1 ,2 = 7.8, H-10), 4.62 (d, 1H, J1,2 = 9.9, H-1), 4.38–4.82 (12H, –
CH2Ph), 4.89 (d, J = 14.7, –CH2Ph), 5.13 (d, J = 11.1, –CH2Ph),
7.14–7.56 (40H, aromatic H); 13C NMR (CDCl3): d 68.1 (C-6), 68.8
(C-60), 73.1, 73.2, 74.8, 74.9, 75.3, 75.4, 75.6, 76.3 (C-4), 77.9
(C-50), 79.2 (C-5), 80.0 (C-2), 82.7 (C-20), 84.8 (C-3or C-30), 84.9
(C-3or C-30), 87.3 (C-1), 102.5 (C-10), 127.3–139 (aromatic C). Mp
0
0
1H NMR (CDCl3): d 3.18 (dd, 1H, J = 3.6, J2,3 = 3.3, H-1), 3.34 (3H,
C6–OCH3), 3.37–3.38 (4H, H-3, C1–OCH3), 3.41–3.45 (3H, C2–
OCH3), 3.47–3.63 (6H, H-4, H-6, C3–OCH3), 4.79 (d, 1H, J1,2 = 3.6,
H-1); 13C NMR (CDCl3): d 55.0 (C1–OCH3), 58.2 (C2–OCH3), 59.2
147–148 °C (mp 152 °C).26
½
a 1D4:7
+10.4 (c 1.081, CHCl3) MALDI-
ꢂ
TOF MS: calcd for C67H68O10S 1064.45 found [M+Na]+ = 1087.39,
[M+K]+ = 1103.39.

1680
A. Nakagawa et al. / Carbohydrate Research 346 (2011) 1671–1683
Figure 10. Surface tension–concentration curves of pure compounds 1–8 and mixtures 9–16; broken lines are surface tension curves of pure compounds and solid lines are
those of mixtures. d: compound 1; s: compound 2; N: compound 3; 4: compound 4; j: compound 5; h: compound 6; ꢀ: compound 7; }: compound 8; ꢁ: mixtures > b;
5: mixtures < b.
a
a
4.3. General method for glycosylation
1), 102.3 (C-100), 126.9–139.4 (aromatic C). Rf (EtOAc/n-hexane
1:1, six times) 0.48. ½a D19:2
ꢂ
+62.5 (c 1.043, CHCl3). MALDI-TOF MS:
The glycosylation was carried out under a high vacuum system.
Glycosyl donor (compound 30 (1.0 equiv)) and acceptor (com-
pounds 27 or 28 (1.5 equiv)) were dissolved in anhydrous EtCN
or CH2Cl2 (2.0 mL) with activated molecular sieves 3 Å or 4 Å (ca.
250 mg), respectively. NBS (1.4 equiv) and AgOTf (a few mg) were
added into the solution at rt. The reaction mixture was stirred at rt
for 24 h. The reaction mixture was filtered with Celite and washed
with EtOAc. The filtrate and washings were diluted with EtOAc,
washed with saturated aq NaHCO3 and brine, dried over Na2SO4,
and concentrated to dryness to give products. After glycosylation,
a part of the products was purified by P-TLC (eluent: EtOAc/n-hex-
ane = 1/2, 1/4(v/v), several times) to give compounds 31–46.
calcd for
C
71H82O16 1190.56 found [M+Na]+ = 1213.56,
[M+K]+ = 1229.53.
4.3.2. Methyl 2,3,4,6-tetra-O-benzyl-b-D-glucopyranosyl-(1?4)-
2,3,6-tri-O-benzyl-b-D-glucopyranosyl-(1?4)-2,3,6-tri-O-
methyl- -glucopyranoside (40)
a-D
1H NMR (CDCl3): d 3.21 (dd, 1H, J = 3.6, J2,3 = 3.6, H-2), 3.25 (C6–
OCH3), 3.30–3.74 (15H, H-20, H-200, H-3, H-30, H-300, H-4, H-400, H-5,
H-50, H-500, H-6, H-60, H-600), 3.40 (C1–OCH3), 3.52 (C2–OCH3), 3.55
(C3–OCH3), 3.88 (dd, 2H, J = 3.3, J = 3.0, H-60), 4.08 (t, 1H, J = 9.3, H-
40), 4.36 (d, 1H, J1 ,2 = 6.0, H-10), 4.54 (d, 1H, J1 ,2 = 6.9, H-100), 4.81
(d, 1H, J1,2 = 3.0 Hz, H-1), 4.49–4.91 (12H, –CH2Ph), 5.13 (d, 1H,
J = 11.4, –CH2Ph), 7.15–7.35 (35H, aromatic H); 13C NMR (CDCl3):
d 55.1 (C1–OCH3), 58.8 (C2–OCH3), 59.2 (C6–OCH3), 60.9 (C3–
OCH3), 67.8 (C-60), 68.8 (C-600), 69.7 (C-5), 70.0 (C-6), 73.1 (–CH2Ph),
73.2 (–CH2Ph), 74.8 (–CH2Ph), 74.9 (–CH2Ph), 75.1 (C-50), 75.6 (C-
500), 76.2 (C-40), 77.4 (C-4), 77.9 (C-400), 80.9 (C-2), 81.5 (C-3), 81.9
(C-20), 82.7 (C-200), 83.4 (C-30), 84.8 (C-300), 97.5 (C-1), 102.4 (C-
100), 102.9 (C-10), 127.0–139.2 (aromatic C). Rf (EtOAc/n-hexane
0
0
00 00
4.3.1. Methyl 2,3,4,6-tetra-O-benzyl-b-
2,3,6-tri-O-benzyl- -glucopyranosyl-(1?4)-2,3,6-tri-O-
methyl- -glucopyranoside (39)
D-glucopyranosyl-(1?4)-
a-D
a-D
1H NMR (CDCl3): d 2.96 (C6–OCH3), 3.26 (dd, 1H, J = 3.6,
J2,3 = 3.9, H-2), 3.31–3.37 (3H, H-200, H-6), 3.39 (C1–OCH3), 3.46
(C2–OCH3), 3.47 (C3–OCH3), 3.50–3.94 (12H, H-4, H-5, H-20, H-30,
H-50, H-60, H-300, H-400, H-500, H-600), 3.70 (t, 1H, J = 9.3, J3,4 = 9.3, H-
3), 4.08 (t, 1H, J = 9.3, H-40), 4.34 (d, J = 12.3, –CH2Ph), 4.44 (d,
1:1, six times) 0.48. ½a D18:6
ꢂ
+42.7 (c 0.994, CHCl3). MALDI-TOF MS:
calcd for
C
71H82O16 1190.56 found [M+Na]+ = 1214.51,
J = 12.3, –CH2Ph), 4.48 (d, 1H, J1 ,2 = 7.8, H-100), 4.54 (d, 1H,
[M+K]+ = 1229.48.
00 00
J = 10.8, –CH2Ph), 4.64 (d, 1H, J = 12.0, –CH2Ph), 4.68–4.88 (9H, –
CH2Ph), 4.80 (d, 1H, J = 3.6, H-1), 5.11 (d, 1H, J = 11.1, –CH2Ph),
5.62 (d, 1H, J = 3.9, H-10), 7.18–7.39 (35H, aromatic H); 13C NMR
(CDCl3): d 55.0 (C1–OCH3), 58.6 (C2–OCH3), 58.7 (C6–OCH3), 60.1
(C3–OCH3), 67.6, 68.8, 68.9, 70.8 (C-6), 71.2 (C-50), 73.2, 73.4,
73.7, 74.3, 74.7, 75.2, 75.2, 75.6, 76.2 (C-40), 78.0, 78.7, 80.3 (C-4),
82.1 (C-2), 82.4 (C-200), 83.3 (C-3), 84.9 (C-20), 96.4 (C-10), 97.0 (C-
4.3.3. Methyl 2,3,4,6-tetra-O-benzyl-b-D-glucopyranosyl-(1?4)-
2,3,6-tri-O-benzyl-a-D-glucopyranosyl-(1?4)-2,3,6-tri-O-
methyl-b- -glucopyranoside (41)
D
1H NMR (CDCl3): d 3.01 (C6–OCH3), 3.05 (dd, 1H, J = 7.8,
J2,3 = 9.0, H-2), 3.34–3.85 (24H, H-20, H-200, H-3, H-30, H-300, H-4,
H-400, H-5, H-50, H-500, H-6, H-60, H-600), 3.44 (C3–OCH3), 3.50 (C1–

A. Nakagawa et al. / Carbohydrate Research 346 (2011) 1671–1683
1681
Table 4
Comparisons of surface tensions of compounds 7, 8 and 15 with those of commonly-used surfactants
Surfactants
CMC (mM)
cCMC (mN/m)
Ref.
0.48 (0.03 wt %)
0.48 (0.0.3 wt %)
32.2
—
—
34.5
36.5
1.6 (0.1 wt %)
—
—
46.0 (0.5 wt %)
30.8
33
34
22.0
0.058
32.7
35.0
35
36
8.0–9.0
0.17
35.3
37
0.8
36.0
40.8
36
38
0.27
Surface tensions of compounds 7, 8, and 15 at concentration of 0.5 wt % were 30.4, 29.0, and 28.0 mN/m, respectively.
OCH3), 3.54 (C2–OCH3), 3.92(dd, 2H, J = 2.4, J = 2.1, H-60), 4.06 (t,
1H, J = 9.3, H-40), 4.15 (d, 1H, J1,2 = 7.8, H-1), 4.31–4.88 (14H, –
4.91 (15H, –CH2Ph), 5.13 (d, 1H, J = 11.1, –CH2Ph), 7.15–7.33
(35H, aromatic H); 13C NMR (CDCl3): d 56.9 (C1–OCH3), 59.0 (C6–
OCH3), 60.5 (C3–OCH3), 60.6 (C2–OCH3), 67.8 (C-60), 68.8 (C-600),
70.2 (C-6), 73.1 (–CH2Ph), 73.2 (–CH2Ph), 74.6 (C-5 or C-50 or C-
500), 74.8 (C-5 or C-50 or C-500), 74.9 (–CH2Ph), 75.0 (–CH2Ph), 75. 6
(C-5 or C-50 or C-500), 76.2 (C-40), 77.2 (C-4 or C-40), 77.9 (C-4 or
C-40), 81.8 (C-200), 82.7 (C-20), 82.9 (C-2), 83.3 (C-30 or C-300), 84.5
(C-3), 84.8 (C-30 or C-300), 102.4 (C-10), 102.8 (C-100), 104.1 (C-1),
127.0–138.5 (aromatic C). Rf (EtOAc/n-hexane 1:1, six times)
00 00
CH2Ph), 5.12 (d, 1H, J = 11.1, –CH2Ph), 4.43 (d, 1H, J1 ,2 = 10.5, H-
100), 5.60 (d, 1H, J1 ,2 = 3.9, H-10), 7.17–7.30 (35H, aromatic H); 13C
NMR (CDCl3): d 56.8 (C1–OCH3), 59.0 (C6–OCH3), 59.3 (C3–OCH3),
60.1 (C2–OCH3), 67.6 (C-600), 68.9 (C-60), 70.8 (C-6), 71.0, 73.3 (–
CH2Ph), 73.4 (–CH2Ph), 73.6, 73.8, 74.4, 74.7, 75.2, 75.6, 76.4 (C-
40), 77.2, 78.0, 78.5 (C-20), 80.2 (C-30), 82.4 (C-200), 83.7 (C-2), 84.8
(C-300), 86.2 (C-3), 96.3 (C-10), 102.4 (C-100), 104.2 (C-1), 127.0–
0
0
138.2(aromatic C). Rf (EtOAc/n-hexane 1:1, six times) 0.76. ½a D20:0
ꢂ
0.76. ½a 1D8:6
ꢂ
+6.17 (c 1.004, CHCl3). MALDI-TOF MS: calcd for
+17.7 (c 1.012, CHCl3). MALDI-TOF MS: calcd for C71H82O16
C
71H82O16 1190.56 found [M+Na]+ = 1213.51, [M+K]+ = 1229.45.
1190.56 found [M+Na]+ = 1213.56, [M+K]+ = 1229.51.
4.3.5. Ethyl 2,3,4,6-tetra-O-benzyl-b-
2,3,6-tri-O-benzyl- -glucopyranosyl-(1?4)-2,3,6-tri-O-ethyl-
-glucopyranoside (43)
D-glucopyranosyl-(1?4)-
4.3.4. Methyl 2,3,4,6-tetra-O-benzyl-b-
2,3,6-tri-O-benzyl-b- -glucopyranosyl-(1?4)-2,3,6-tri-O-
methyl-b- -glucopyranoside (42)
D-glucopyranosyl-(1?4)-
a-D
D
a-D
D
1H NMR (CDCl3): d 0.9–1.25 (12H, –CH2–CH3), 3.09–3.94 (25H,
1H NMR (CDCl3): d 3.01 (dd, 1H, J = 7.8, J2,3 = 9.0, H-2), 3.19–3.44
(9H, H-20, H-200, H-3, H-5, H-50, H-500, –OCH3), 3.24 (C6–OCH3),
3.46–3.72 (19H, H-30, H-300, H-4, H-400, H-6, H-60, H-600 –CH3), 3.51
(C1–OCH3), 3.55 (C3–OCH3), 3.57 (C2–OCH3), 3.88 (dd, 2H, J = 3.3,
J = 3.0, H-60), 4.08 (t, 1H, J = 9.3, H-40), 4.15 (d, 1H, J1,2 = 7.8, H-1),
H-2, H-20, H-200, H-3, H-30, H-300, H-4, H-400, H-5, H-50, H-500, H-6,
H-60, H-600, –CH2–CH3), 4.11 (t, 1H, J = 9.6, H-40), 4.32–4.87 (14H,
H-100, –CH2Ph), 4.89 (d, 1H, J1,2 = 3.6, H-1), 5.12 (d, J = 10.2, –CH2Ph),
5.73 (d, 1H, J1 ,2 = 3.9, H-10), 7.19–7.39 (35H, aromatic H); 13C NMR
(CDCl3):d 14.8, 15.0, 15.6, 15.9 (–CH2–CH3), 63.1, 66.5, 66.7, 67.9,
0
0
4.40 (d, 1H, J1 ,2 = 8.1, H-100), 4.55 (d, 1H, J1 ,2 = 7.8, H-10), 4.37–
00 00
0
0

1682
A. Nakagawa et al. / Carbohydrate Research 346 (2011) 1671–1683
68.9, 69.1, 69.2 (C-6, C-60, C-600, –CH2–CH3), 70.8, 71.5, 73.2, 73.4,
74.0, 74.4, 74.7, 75.2 (–CH2Ph), 75.6, 76.2 (C-40), 78.1, 78.8, 80.4
(C-4), 80.7 (C-2), 81.6 (C-3), 82.5 (C-200), 84.8 (C-20), 96.0 (C-10),
96.2 (C-1), 102.4 (C-100), 127.0–139.4 (aromatic C). Rf (EtOAc/n-hex-
mixture was stirred at rt under hydrogen atmosphere overnight.
The Pd(OH)2 on C was filtered off and washed with 20% MeOH/
CH2Cl2 (v/v) and MeOH. The combined filtrate and washings were
concentrated to dryness to give products.
ane 1:2, six times) 0.65. ½a D17:0
ꢂ
+58.6 (c 0.775, CHCl3). MALDI-TOF
MS: calcd for
C
75H90O16 1246.62 found [M+Na]+ = 1269.40,
4.4.1. Methyl b-
D
-glucopyranosyl-(1?4)-
a-D-glucopyranosyl-
[M+K]+ = 1285.34.
(1?4)-2,3,6-tri-O-methyl-a-D
-glucopyranoside (1)
Debenzylation of compound 1 gave compound 39 (17.9 mg) in
ca. 100% yield (8.7 mg).
4.3.6. Ethyl 2,3,4,6-tetra-O-benzyl-b-
2,3,6-tri-O-benzyl-b- -glucopyranosyl-(1?4)-2,3,6-tri-O-ethyl-
-glucopyranoside (44)
D-glucopyranosyl-(1?4)-
D
1H NMR (D2O): d 3.15–3.77 (18H, H-2, H-20, H-200, H-3, H-30, H-
300, H-4, H-40, H-400, H-5, H-50, H-500, H-6, H-60, H-600), 3.33 (C6–
OCH3), 3.39 (C1–OCH3), 3.46 (C2–OCH3), 3.56 (C3–OCH3), 4.52 (d,
a-D
1H NMR (CDCl3): d 1.09–1.27 (12H, –CH2–CH3), 3.29 (dd, 1H,
J = 3.6, J2,3 = 3.6, H-2), 3.37–3.95 (24H, H-20, H-200, H-3, H-30, H-300,
H-4, H-400, H-5, H-50, H-500, H-6, H-60, H-600, –CH2–CH3), 4.09 (t,
1H, J1 ,2 = 7.8, H-100), 4.97 (d, 1H, J1,2 = 3.3, H-1), 5.40 (d, 1H,
00 00
J1 ,2 = 3.9, H-10); 13C NMR (D2O): d 57.6 (C1–OCH3), 60.6 (C2–
OCH3), 60.9 (C6–OCH3), 62.1 (C-60 or C-600), 62.4 (C3–OCH3), 63.2
(C-60 or C-600), 71.2, 72.1, 73.1 (C-6), 73.7, 73.9, 74.5, 75.8 (C-200),
78.2 (C-20 or C-300), 78.6 (C-20 or C-300), 80.7 (C-30), 83.4 (C-2),
0
0
1H, J = 9.0, J = 9.3, H-40), 4.37 (d, 1H, J1 ,2 = 8.7, H-100), 4.49 (d, 1H,
00 00
J1 ,2 = 9.6, H-10), 4.87 (d, 1H, J1,2 = 3.9, H-1), 4.36–4.9 (13H, –CH2Ph),
0
0
5.12 (d, 1H, J = 11.1, –CH2Ph), 7.16–7.35 (35H, aromatic H);13
C
NMR (CDCl3): d 14.9, 15.1, 15.6, 15.7 (–CH2–CH3), 63.1, 66.3,
66.9, 67.9, 68.0, 68.6, 68.8 (–CH2–CH3), 69.9, 73.1, 74.7, 74.9,
75.0, 75.1 (–CH2Ph), 75.6, 76.3 (C-40), 77.5 (C-4), 77.9 (C-400), 79.4
(C-3), 79.7 (C-2), 81.8 (C-200), 82.6 (C-20), 83.4 (C-300), 84.8 (C-30),
96.6 (C-1), 102.4 (C-10), 102.9 (C-100), 127.0–139.3 (aromatic C). Rf
85.7 (C-3), 99.2 (C-1), 100.7 (C-10), 105.1 (C-100). ½a 1D9:2
ꢂ
+59.1 (c
0.220, water). MALDI-TOF MS: calcd for C22H40O16 560.23 found
[M+Na]+ = 583.29.
4.4.2. Methyl b-
D
-glucopyranosyl-(1?4)-b-
D-glucopyranosyl-
(EtOAc/n-hexane 1:2, six times) 0.65. ½a D17:5
ꢂ
+44.7 (c 0.853, CHCl3).
C75H90O16 1246.62 found
(1?4)-2,3,6-tri-O-methyl-
a
-D
-glucopyranoside (2)
MALDI-TOF MS: calcd for
Debenzylation of compound 2 gave compound 40 (25.6 mg) in
[M+Na]+ = 1269.42, [M+K]+ = 1285.39.
95% yield (11.4 mg).
1H NMR (D2O): d 3.15–3.77 (18H, H-2, H-20, H-200, H-3, H-30, H-
300, H-4, H-40, H-400, H-5, H-50, H-500, H-6, H-60, H-600), 3.37 (C6–
OCH3), 3.39 (C1–OCH3), 3.46 (C3–OCH3), 3.55 (C2–OCH3), 4.40 (d,
4.3.7. Ethyl 2,3,4,6-tetra-O-benzyl-b-D-glucopyranosyl-(1?4)-
2,3,6-tri-O-benzyl-a-D-glucopyranosyl-(1?4)-2,3,6-tri-O-ethyl-
b- -glucopyranoside (45)
D
1H, J1 ,2 = 8.1, H-10), 4.50 (d, 1H, J1 ,2 = 7.8, H-100), 4.98 (d, 1H,
J1,2 = 3.6, H-1; 13C NMR (D2O): d 57.6 (C1–OCH3), 60.5 (C2–OCH3),
60.8 (C6–OCH3), 62.1 (C3–OCH3), 62.6 (C-60), 63.2 (C-600), 71.8,
72.1, 72.4 (C-6), 75.8 (C-20 or C-200), 75.9 (C-20 or C-200), 76.9, 77.5,
78.1, 78.3, 78.6 (C-4), 81.1 (C-40), 82.1 (C-2), 83.0 (C-3), 99.2 (C-
0
0
00 00
1H NMR (CDCl3):d 0.89–1.25 (12H, –CH2–CH3), 3.18–3.94 (24H,
H-20, H-200, H-3, H-30, H-300, H-4, H-400, H-5, H-50, H-500, H-6, H-60, H-
600, –CH2–CH3), 3.12 (dd, 1H, J = 8.1, J2,3 = 9.3, H-2), 4.08 (t, 1H,
J = 9.3, H-40), 4.23 (d, 1H, J1,2 = 7.5, H-1), 4.32–4.46 (13H, –CH2Ph),
4.45 (d, 1H, J1 ,2 = 6.0, H-100), 5.12 (d, 1H, J = 11.4, –CH2Ph), 5.68
(d, 1H, J = 3.9, H-10), 7.17–7.39 (35H, aromatic H);13C NMR (CDCl3):
d 15.1, 15.2, 15.6, 15.8 (–CH2–CH3), 65.4, 67.0, 67.6, 68.1 (–CH2–
CH3), 68.9, 69.4, 70.8 (C-4), 71.4, 73.2, 73.4, 74.0, 74.3, 74.6, 74.7,
75.1, 75.2 (–CH2Ph), 75.6, 76.4 (C-40), 77.2, 78.0, 78.5 (C-20), 80.4
(C-30), 82.4 (C-2), 82.5 (C-200), 84.7 (C-3 or C-300), 84.8 (C-3 or C-
300), 96.1 (C-10), 102.5 (C-100), 103.1 (C-1), 127.0–139.4 (aromatic
0
0
1), 105.0 (C-10), 105.2 (C-100). ½a 2D0:0
ꢂ
+37.9 (c 0.222, water). MAL-
DI-TOF MS calcd for C22H40O16 560.23 found [M+Na]+ = 583.18.
4.4.3. Methyl b-
D
-glucopyranosyl-(1?4)-
a-D-glucopyranosyl-
(1?4)-2,3,6-tri-O-methyl-b-
D-glucopyranoside (3)
Debenzylation of compound 3 gave compound 41 (17.5 mg) in
ca. 100% yield (8.6 mg).
C). Rf (EtOAc/n-hexane 1:2, six times) 0.79. ½a D16:7
ꢂ
+22.2 (c 0.862,
1H NMR (D2O) :d 3.25–3.91 (18H, H-2, H-20, H-200, H-3, H-30, H-
300, H-4, H-40, H-400, H-5, H-50, H-500, H-6, H-60, H-600), 3.10 (t, 1H,
J = 8.4, J = 8.7, H-2), 3.33 (C6–OCH3), 3.53 (C1–OCH3), 3.56 (C2–
OCH3), 3.59 (C3–OCH3), 4.40 (d, 1H, J1,2 = 7.8, H-1), 4.50 (d, 1H,
CHCl3). MALDI-TOF MS: calcd for C75H90O16 1246.62 found
[M+Na]+ = 1269.45, [M+K]+ = 1285.39.
4.3.8. Ethyl 2,3,4,6-tetra-O-benzyl-b-
2,3,6-tri-O-benzyl-b- -glucopyranosyl-(1?4)-2,3,6-tri-O-ethyl-
b- -glucopyranoside (46)
1H NMR (CDCl3): d 1.08–1.24 (12H, –CH2–CH3), 3.09 (dd, 1H,
D-glucopyranosyl-(1?4)-
J1 ,2 = 8.1, H-100), 5.38 (d, 1H, J1 ,2 = 3.9, H-10); 13C NMR (D2O): d
59.9 (C1–OCH3), 61.0 (C6–OCH3), 62.1 (C-60 or C-600), 62.2 (C2–
OCH3), 62.6 (C3–OCH3), 63.2 (C-60 or C-600), 72.1, 73.2 (C-6), 73.7,
73.8, 73.9 (C-4), 74.5, 75.5 (C-30), 75.8 (C-200), 78.3 (C-20 or C-300),
78.6 (C-20 or C-300), 80.7 (C-40), 85.7 (C-2), 88.3 (C-3), 100.5 (C-10),
00 00
0
0
D
D
J = 8.1, J2,3 = 8.7, H-2), 3.26–3.92 (24H, H-20, H-200, H-3, H-30, H-300,
H-4, H-400, H-5, H-50, H-500, H-6, H-60, H-600, –CH2–CH3), 4.09 (t,
1H, J = 9.0, J = 9.6, H-40), 4.22 (d, 1H, J1,2 = 8.1, H-1), 4.35–4.90
(16H, H-10, H-100, –CH2Ph), 5.12 (d, 1H, J = 11.4, –CH2Ph),
7.17–7.35 (35H, aromatic H); 13C NMR (CDCl3): d 15.2, 15.7, 15.8
(–CH2–CH3), 65.4, 66.5, 67.8, 68.3, 68.5, 68.7, 68.8 (C-6, C-60, C-600,
–CH2–CH3), 73.1, 74.7, 74.9 (–CH2Ph), 75.6, 76.3 (C-40), 77.2, 77.7,
77.9 (–CH2Ph), 81.6 (C-2), 81.8 (C-200), 82.6 (C-20 or C-3), 82.9 (C-
20 or C-3), 83.3 (C-30 or C-300), 84.8 (C-30 or C-300), 102.4 (C-10),
102.9 (C-100), 103.2 (C-1), 127.0–139.3 (aromatic C). Rf (EtOAc/n-
105.1 (C-100), 105.7 (C-1). ½a 2D0:8
ꢂ
+32.0 (c 0.220, water). MALDI-
TOF MS: calcd for C22H40O16 560.23 found [M+Na]+ = 583.4.
4.4.4. Methyl b-
D
-glucopyranosyl-(1?4)-b-
D-glucopyranosyl-
(1?4)-2,3,6-tri-O-methyl-b-
D-glucopyranoside (4)
Debenzylation of compound 4 gave compound 42 (24.1 mg) in
98.2% yield (11.1 mg).
1H NMR (D2O): d 3.08 (t, 1H, J = 8.1, J2,3 = 9.3, H-2), 3.32–3.62
(10H, H-20, H-200, H-3, H-30, H-300, H-4, H-400, H-5, H-50, H-500), 3.37
(C6–OCH3), 3.39 (C1–OCH3), 3.46 (C3–OCH3), 3.55 (C2–OCH3),
3.67–3.98 (7H, H-40, H-6, H-60, H-600), 4.40 (d, 1H, J = 7.8, H-1 or
hexane 1:2, six times) 0.79. ½a D16:9
ꢂ
+11.6 (c 0.684, CHCl3). MALDI-
TOF MS: calcd for C75H90O16 1246.62 found [M+Na]+ = 1269.42,
[M+K]+ = 1285.40.
H-10), 4.41 (d, 1H, J = 7.5, H-1 or H-10), 4.49 (d, 1H, J1 ,2 = 7.8, H-
00 00
100; 13C NMR (D2O): d 59.8 (C1–OCH3), 60.9 (C6–OCH3), 62.0 (C2–
OCH3 or C3–OCH3), 62.6 (C-60 or C-600 or C2–OCH3 or C3–OCH3),
63.2 (C-60 or C-600), 72.1, 72.6 (C-6), 75.8 (C-20 or C-200), 75.9 (C-20
or C-200), 76.1, 76.9, 77.5, 78.1, 78.4, 78.6 (C-40), 81.1 (C-4), 84.4
4.4. General method for debenzylation
To a solution of benzylated trisaccharide derivative in THF
(0.1 mL) and EtOH (0.9 mL), Pd(OH)2 on C was added. The reaction

A. Nakagawa et al. / Carbohydrate Research 346 (2011) 1671–1683
1683
(C-2), 85.7 (C-3), 104.9 (C-10), 105.2 (C-100), 105.6 (C-1). ½a 2D2:8
ꢂ
ꢀ15.9
10).
C
½
a 2D2:9
ꢂ
ꢀ2.9 (c 0.220, water). MALDI-TOF MS: calcd for
(c 0.220, water). MALDI-TOF MS: calcd for C22H40O16 560.23 found
26H48O16 616.29 found [M+Na]+ = 639.48.
[M+Na]+ = 583.51.
Acknowledgments
4.4.5. Ethyl b-
D-glucopyranosyl-(1?4)-a-D-glucopyranosyl-
(1?4)-2,3,6-tri-O-ethyl-
a
-D
-glucopyranoside (5)
This investigation was supported in part by a Grant-in-Aid for
Scientific Research from the Ministry of Education, Science, and
Culture of Japan (Nos. 18680009 and 21580205).
Debenzylation of compound 5 gave compound 43 (18.0 mg) in
96% yield (8.6 mg).
1H NMR (D2O): d 1.14–1.23 (12H, –CH2–CH3), 3.28–3.96 (26H,
H-2, H-20, H-200, H-3, H-30, H-300, H-4, H-400, H-5, H-50, H-500, H-6,
H-60, H-600, –CH2–CH3), 4.51 (d, J1 ,2 = 7.8, H100), 5.03 (d, J1,2 = 3.6,
References
00 00
H1), 5.47 (d, J1 ,2 = 3.6, H10); 13C NMR (D2O): d 16.7, 17.3, 17.4 (–
CH2–CH3), 62.2, 63.2, 66.5, 69.5, 69.6, 71.3, 71.4, 71.6, 72.1, 73.7,
73.8, 74.1, 74.8, 75.8 (C-200), 78.3, 78.6 (C-20), 80.6, 82.1 (C-2),
0
0
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4.4.6. Ethyl b-
(1?4)-2,3,6-tri-O-ethyl-
D
-glucopyranosyl-(1?4)-b-
D-glucopyranosyl-
a-D-glucopyranoside (6)
Debenzylation of compound 6 gave compound 44 (40.7 mg) in
96.9% yield (19.5 mg).
1H NMR (D2O): d 1.15–1.22 (12H, –CH2–CH3), 3.26–3.99 (26H,
H-2, H-20, H-200, H-3, H-30, H-300, H-4, H-40, H-400, H-5, H-50, H-500,
H-6, H-60, H-600, –CH2–CH3), 4.41 (d, 1H, J1 ,2 = 7.8, H-10), 4.49 (d,
0
0
1H, J1 ,2 = 7.8, H-100), 5.01 (d, 1H, J1,2 = 3.3, H-1);13C NMR (D2O): d
00 00
16.6, 16.8, 17.2, 17.3 (–CH2–CH3), 62.9, 63.2, 66.4, 69.3, 69.8,
70.5, 71.5 (–CH2–CH3), 72.0, 72.1, 75.8 (C-20 or C-200), 75.9 (C-20
or C-200), 76.9, 77.7, 78.1, 78.6, 78.8, 81.1 (C-2), 81.4, 81.8, 98.5
(C-1), 104.7 (C-10), 105.2 (C-100). ½a 2D2:8
ꢂ
+51.0 (c 0.220, water). MAL-
DI-TOF MS: calcd for C26H48O16 616.29 found [M+Na]+ = 639.48.
4.4.7. Ethyl b-
(1?4)-2,3,6-tri-O-ethyl-b-
D-glucopyranosyl-(1?4)-
a-D-glucopyranosyl-
D
-glucopyranoside (7)
Debenzylation of compound 7 gave compound 45 (7.1 mg) in
ca. 100% yield (3.8 mg).
1H NMR (D2O): d 1.13–1.23 (12H, –CH2–CH3), 3.15 (t, 1H, J = 8.4,
J2,3 = 9.0, H-2), 3.27 (t, 1H, J = 7.8, J2 ,3 = 9.3, H-200) 3.37–3.96 (24H,
00 00
H-20, H-3, H-30, H-300, H-4, H-40, H-400, H-5, H-50, H-500, H-6, H-60, H-
600, –CH2–CH3), 4.46 (d, 1H, J1,2 = 8.4, H-1), 4.49 (d, 1H, J1 ,2 = 8.1, H-
00 00
100), 5.44 (d, 1H, J1 ,2 = 3.9, H-10);13C NMR (D2O): d 16.1, 16.4, 16.7,
16.8 (–CH2–CH3), 61.6, 62.6, 68.7, 69.0, 70.9, 71.1, 71.2, 71.4, 73.1,
73.2, 73.4 (C-4), 74.2, 75.1 (C-30), 75.2 (C-200), 77.7 (C-300), 78.0 (C-
20), 80.1 (C-40), 83.8 (C-2), 86.2 (C-3), 99.6 (C-10), 104.0 (C-100),
0
0
104.5 (C-1). ½a D22:7
ꢂ
+28.6 (c 0.220, water). MALDI-TOF MS: calcd
for C26H48O16 616.29 found [M+Na]+ = 639.50.
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4.4.8. Ethyl b-
(1?4)-2,3,6-tri-O-ethyl-b-
D
-glucopyranosyl-(1?4)-b-
D-glucopyranosyl-
D
-glucopyranoside (8)
Debenzylation of compound 8 gave compound 46 (7.7 mg) in
ca. 100% yield (3.8 mg).
1H NMR (D2O): d 1.15–1.23 (12H, –CH2–CH3), 3.25–3.98 (25H,
H-20, H-200, H-3, H-30, H-300, H-4, H-40, H-400, H-5, H-50, H-500, H-6,
H-60, H-600, –CH2–CH3), 3.09 (t, 1H, J1,2 = 8.1, J2,3 = 9.0, H-2), 4.41
(d, 1H, J1 ,2 = 6.3, H-10), 4.44 (d, 1H, J1,2 = 8.1, H-1), 4.48 (d, 1H,
0
0
J1 ,2 = 7.8, H-100); 13C NMR (D2O): d 16.8, 16.9, 17.2, 17.3 (–CH2–
00 00
CH3), 62.8, 63.2, 69.3 (C-20 or C-200), 69.5 (C-20 or C-200), 70.7, 71.8,
72.0, 75.8, 75.9, 76.4, 76.9, 77.7, 78.1 (C-300), 78.6, 78.8 (C-4), 81.4
(C-40), 83.5 (C-2), 84.6 (C-3), 104.5 (C-100), 104.7 (C-1), 105.2 (C-