Synthesis and molecular aggregation of new sugar bola-amphiphiles

Article abstract of DOI:10.1016/S0008-6215(99)00162-7

Novel bola-amphiphilic compounds have been synthesized with D-galactose or lactose as polar head groups. The sugar groups are attached to the six-, ten- or twelve-polymethylene bridging chain by a carbamate function. Vesicles are obtained for some of thes

Full text of DOI:10.1016/S0008-6215(99)00162-7

www.elsevier.nl/locate/carres
Carbohydrate Research 321 (1999) 15–23
Synthesis and molecular aggregation of new sugar
bola-amphiphiles
Carla Prata, Nathalie Mora, Ange Polidori, Jean-Michel Lacombe *, Bernard Pucci
Laboratoire de Chimie Bioorganique et des Syste`mes Mole´culaires Vectoriels, Faculte´ des Sciences d’A6ignon,
33 rue Louis Pasteur, F-84000 A6ignon, France
Received 13 January 1999; revised 3 June 1999; accepted 18 June 1999
Abstract
Novel bola-amphiphilic compounds have been synthesized with
D
-galactose or lactose as polar head groups. The
sugar groups are attached to the six-, ten- or twelve-polymethylene bridging chain by a carbamate function. Vesicles
are obtained for some of these derivatives. © 1999 Elsevier Science Ltd. All rights reserved.
Keywords: Bola-amphiphile surfactants; Sugar head group; Aggregation properties
tial application in pharmacy and chemistry
1. Introduction
[5–7]. The use of sugar as the polar head can
offer greater potential for interaction at the
cell surface by molecular recognition.
A bola-amphiphile is defined as a molecule
in which two or more hydrophilic groups are
connected by a hydrophobic bridging chain
[1]. Over recent years there has been increas-
ing interest in such surfactants from both
fundamental and applied points of view. Most
of these compounds have been studied for
their polymorphic behavior in water as a func-
tion of their structures [2–4]. When dispersed
in aqueous medium, upon sonication, these
molecules often self-organize into monolayer
vesicles (monolayer lipid membranes), which
are stable over a long period of time to varia-
tions of temperature or to ionic strength
changes and could be used as membrane
models.
We describe here the synthesis and aggrega-
tion properties of new sugar-based bolaforms
with different polar heads and alkyl chain
having the following general formula:
[sugar]ꢀY1ꢀXꢀY2ꢀ[sugar]
where
Y1=ꢀOC(O)NHꢀ
and
Y2=
ꢀNHC(O)Oꢀ; Y1=ꢀNHC(S)NHꢀ and Y2=
ꢀC(O)NHꢀ; X is a polymethylene bridging
chain
The polar head is derived from
D
-galactose
or lactose. A variety of compounds were pre-
pared in order to determine the relationship
between molecular structure and the nature of
the aggregates.
Bola-amphiphile surfactants involving sugar
at both ends have been synthesized, because of
their ability to form vesicles and supramolecu-
lar arrangements, and because of their poten-
2. Results and discussion
Synthesis of bis(O-galactopyranosyl) and
bis(O-lactosyl) bis(carbamate) 7–10.—These
derivatives were obtained by reaction of one
* Corresponding author. Fax: +33-4-90-14-44-49.
0008-6215/99/$ - see front matter © 1999 Elsevier Science Ltd. All rights reserved.
PII: S0008-6215(99)00162-7

16
C. Prata et al. / Carbohydrate Research 321 (1999) 15–23
molar equivalent of a a,v-polymethylene di-
configuration was confirmed by the chemical
shifts of the anomeric carbon (92 and 93
ppm). Zemple´n O-deacetylation afforded the
bola-amphiphiles 11 and 12 in almost quanti-
tative yield.
isocyanate with two equivalents of 2,3,4,6-te-
tra-O-acetyl- -galactopyranose or 2,3,6,2%,3%,
D
4%,6%-hepta-O-acetyl-lactose [8]. The reaction
was performed in toluene in the presence of
1,4-diazabicyclo[2.2.2]octane at room temper-
ature for 8 h. Such reaction conditions al-
lowed us to obtain the b anomer with
complete diastereoselectivity [9,10]. The ex-
pected compounds (1–4) were obtained in
good yield (ca. 70%) after flash chromatogra-
phy. Their structure was confirmed by NMR
spectroscopy. The single resonance observed
for C-1 (92–93 ppm) demonstrates that only
one anomer is present. The b anomeric
Synthesis of the galactopyranosylthiourea
deri6ati6e 17.—The complete reaction scheme
for the preparation of this bola-amphiphile is
shown in Scheme 1. The amino group of
11-amino decanoic acid was first protected
with a N-benzyloxycarbonyl group. This
product was reacted with the per-O-acetyl-b-
lactosyl isothiocyanate 14 [11] in toluene in
the presence of 1,4-diazabicyclo[2.2.2]octane
at room temperature. The structure of the
resulting compound 15 was confirmed by
NMR spectroscopy. Deprotection of the
amino group was performed by hydrogenation
with palladium-on-carbon in methanol and
the resulting amino compound was reacted
1
configuration is clearly established by the H
NMR spectrum, which demonstrates the 1,2-
trans relationship between H-1 and H-2 (5.6–
5.7 ppm, J1,2 8 Hz).
These bola-amphiphiles were O-deacety-
lated using the Zemple´n procedure to give the
expected compounds 7–10 in quantitative
yields.
with 2,3,4,6-tetra-O-acetyl-b- -galactopyra-
D
nosyl isothiocyanate [11] to obtain the bola-
amphiphile 16 in 50% yield after purification
by flash chromatography. The structure of 16
was confirmed by NMR spectroscopy. The
chemical shifts observed for C-1 (90.09 ppm)
and C-1% (101.03 ppm) of the lactose moiety,
and C-1 (89.21 ppm) of the galactose part
confirmed the b anomeric configuration at
both sites. Compound 16 was finally O-
deacetylated using the Zemple´n procedure to
afford 17 in almost quantitative yield.
Molecular aggregation in aqueous solu-
tion.—In a preliminary study, the solubility in
water of these compounds was measured at
20 °C. Compounds 7, 9 and 11, with a six-
methylene chain, exhibited a solubility of
about 10 g/L. Compounds 8, 10 and 12, with
a chain of twelve methylene groups, exhibited
a solubility of about 5 g/L. As expected, the
elongation of the hydrophobic chain reduces
the solubility. The bolaform 17 with a chain of
ten methylene groups exhibited a solubility of
about 10 g/L, similar to that of 7, 9 and 11
with six methylene groups. This is probably
due to introduction of the amide linkage.
Surface tension measurements for com-
pounds 8, 10 and 12 showed the absence of
micellization, which was attributed to the in-
ability of the alkyl chain to bend [12].
Synthesis of O-galactopyranosyl O-lactosyl
bis(carbamate) 11 and 12.—These compounds
were obtained, in a one-pot sequence, by suc-
cessive addition of 2,3,4,6-tetra-O-acetyl- -
D
galactopyranose and 2,3,6,2%,3%,4%,6%-hepta-O-
acetyl-lactose [8] to a long-chain alkyl diiso-
cyanate in toluene. The expected compounds
(5 and 6) were obtained in 40% yield after
flash chromatography on silica gel. The struc-
tures of these compounds were confirmed by
13C NMR spectroscopy. The single resonance
observed for each anomeric carbon demon-
strates that a single isomer is present. The b

C. Prata et al. / Carbohydrate Research 321 (1999) 15–23
17
Scheme 1. (i) DABCO, toluene, rt; (ii) Pd–H2, MeOH; (iii) 2,3,4,6-tetra-O-acetyl-b-D-galactosyl isothiocyanate, DABCO, toluene,
rt; (iv) NaOMe–MeOH.
and of 408 nm for the larger vesicle. Bola-am-
phiphile 10 presented a agglomeration of vesi-
cles (Fig. 2), with a size of 114 nm for the
smaller vesicle and of 408 nm for the larger
vesicle. Compound 12 gave vesicles and
tubules (Figs. 3 and 4). The vesicles had a
diameter of 51 nm for the smaller one and of
The formation of vesicles and supramolecu-
lar arrangements were specified by quasi-elas-
tic light-scattering measurements. Aggregates
were observed after sonication of various
bola-amphiphiles solutions at 1.1 to 1.9×
10−2 M and 25 °C. The stability and the
diameter of the aggregates are reported in
Table 1.
Table 1
We also examined the particles by the elec-
tron microscopy technique. After sonication
of the bolaform solutions, the dispersion was
placed on a grid, stained with phosphotungstic
acid and dried. The presence of vesicles was
observed for compounds 9, 10, 12 and 17,
whereas compounds with a short chain length
and galactose as polar head did not form
vesicles. Compound 9 gave vesicles (Fig. 1)
with a diameter of 28 nm for the smaller one
Stability and diameter of the aggregates in bola-amphiphiles
solutions
Compound Stability of solution a
(days)
QLS mean diameter
(nm)
9
10
11
12
17
2
1
5
2
10
420
246
37
833
45
a Measured at 25 °C in water.

18
C. Prata et al. / Carbohydrate Research 321 (1999) 15–23
Fig. 1. Electron micrograph of compound 9 (negative staining
by phosphotungstic acid).
Fig. 3. Electron micrograph of compound 12 (negative stain-
ing by phosphotungstic acid).
cles were not stable and fused. The electron
microscopic dispersions supported the light-
scattering results. The importance of the
length of the hydrophobic chain and of the
Fig. 2. Electron micrograph of compound 10 (negative stain-
ing by phosphotungstic acid).
152 nm for the larger one. Aggregation with
subsequent fusion was observed. Study of
compound 17 by electron microscopy showed
the formation of vesicles (Fig. 5). These vesi-
Fig. 4. Electron micrograph of compound 12 (negative stain-
ing by phosphotungstic acid).

C. Prata et al. / Carbohydrate Research 321 (1999) 15–23
19
in aq soln at 20 °C, using the ring method
with a Tensiometer Kruss K-12.
The compounds were weighed out to make
1.1 to 1.9×10−2 M suspensions in deionized
water, which were then sonicated for 30 min
using a Branson B-30 cell disruptor working
at a frequency of 20 kHz with a maximum
power of 350 W. The suspensions were filtered
through Dynagard 0.45 mm. The quasi-elastic
light-scattering measurements were performed
with a Semathec F60 apparatus.
The formation of vesicles was also observed
by transmission electron microscopy accord-
ing to the negative staining method. The dis-
persion was applied on a grid covered with a
Formvar membrane, using the drop method: a
drop of the liquid dispersion was placed on
the grid for 1 min, and the excess was then
removed with a filter paper. The sample was
colored by depositing a drop of phospho-
tungstic acid (2%, pH adjusted to 7) for 1 min,
the excess being removed using a filter paper.
The grid was then dried in an oven at 60 °C.
The sample was examined using a Philips
microscope (CM/2 model) at 80 kV.
Fig. 5. Electron micrograph of compound 17 (negative stain-
ing by phosphotungstic acid).
polar head in the formation of vesicles is to be
noticed. A short chain or a short head do not
form vesicles.
General procedure for the synthesis of sym-
metrical bola-amphiphiles.—A mixture of the
reducing sugar (2 mmol), alkyl diisocyanate (1
mmol)
and
1,4-diazabicyclo[2.2.2]octane
3. Experimental
(DABCO) in toluene was stirred at room tem-
perature (rt) for 18 h. After evaporation to
dryness, the mixture was chromatographed on
silica gel with 3:2 EtOAc–hexane.
General methods.—Melting points were de-
termined on an electrothermal 9100 apparatus
and were uncorrected. TLC analysis was per-
formed on aluminum sheets coated with Silica
Gel 60 F 254 (E. Merck). Compounds were
visualized by spraying the TLC plates with
dilute 10% H2SO4 in EtOH followed by char-
ring at 150 °C for a few minutes. Column
chromatography was performed on Silica Gel
Si 60. Optical rotations were recorded on a
Perkin–Elmer 241 polarimeter in a 1 dm cell.
Bis[O-(2,3,4,6-tetra-O-acetyl-i- -galac-
D
topyranosyl)] 1,6-hexanediylbis(carbamate) (1).
Needles from EtOAc–hexane (71%); mp 47–
1
50 °C; [h]2D0 +14.3° (c 1.0, CH2Cl2); H NMR
(CDCl3): 5.65 (d, 2 H, J1,2 8.22, H-1), 5.43 (d,
2 H, H-4), 5.30 (dd, 2 H, H-2), 5.10 (dd, 2 H,
H-3), 4.98 (t, 2 H, NH), 4.06–4.24 (m, 6 H,
H-5, H-6, H-6%), 3.16–3.21 (m, 4 H, CH2),
2.06 (s, 6 H, CH3), 2.05 (s, 6 H, CH3), 2.04 (s,
6 H, CH3), 2.00 (s, 6 H, CH3), 1.51 (m, 4 H,
13
1H and C NMR spectra were recorded on a
Bruker AC 250 spectrometer working at 250
and 80 MHz, respectively, with Me4Si as inter-
nal reference. Elemental analyses were per-
formed by the ‘Service Central de
Microanalyse de Montpellier’.
All reagents were of commercial quality and
were purchased from Aldrich.
13
CH2), 1.33 (m, 4 H, CH2); C NMR (CDCl3):
170.31, 170.12, 169.94 and 169.93 (CH3CO),
153.78 (CONH), 93.26 (C-1), 71.41 (C-5),
70.89 (C-3), 67.98 (C-2), 66.88 (C-4), 60.95
(C-6), 40.90, 29.53 and 26.10 (CH2), 20.73,
20.64, 20.61 and 20.52 (CH3CO). Anal. Calcd
for C36H52N2O22: C, 50.00; H, 6.06; N, 3.24.
Found: C, 49.62; H, 6.14; N, 3.18.
The critical micelle concentration (cmc) was
determined by measuring the surface tension

20
C. Prata et al. / Carbohydrate Research 321 (1999) 15–23
3.89 (m, 6 H, H-6, H-6%, H-5%), 3.13–3.18 (m,
4 H, CH2), 2.11 (s, 6 H, CH3), 2.07 (s, 6 H,
CH3), 2.05 (s, 6 H, CH3), 2.04 (s, 6 H, CH3),
2.02 (s, 6 H, CH3), 2.01 (s, 6 H, CH3), 1.97 (s,
6 H, CH3), 1.48 (m, 4 H, CH2), 1.31 (s, 16 H,
CH2); 13C NMR (CDCl3): 170.35, 170.15,
170.06, 170.01, 169.93, 169.83 and 169.56
(CH3CO), 153.66 (CONH), 100.94 (C-1%),
92.65 (C-1), 75.77 (C-3), 73.32 (C-5), 72.73
(C-4), 71.04 (C-2), 70.73 (C-5%), 70.66 (C-3%),
69.13 (C-2%), 66.71 (C-4%), 61.91 (C-6), 60.90
(C-6%), 40.20, 29.70, 29.63, 29.49, 29.21 and
26.14 (CH2), 20.76, 20.65, 20.61, 20.57, 20.48,
20.44 and 20.39 (CH3CO). Anal. Calcd for
C66H96N2O38: C, 51.96; H, 6.34; N, 1.34.
Found: C, 52.01; H, 6.41; N, 1.26.
Bis[O-(2,3,4,6-tetra-O-acetyl-i- -galactopy-
D
ranosyl)] 1,12-dodecanediylbis(carbamate) (2).
White powder (71%); mp 57–58 °C; [h]D20
+
1
17.0° (c 1.0, CH2Cl2); H NMR (CDCl3): 5.65
(d, 2 H, J 8.25, H-1), 5.43 (d, 2 H, H-4), 5.30
(dd, 2 H, H-2), 5.08 (dd, 2 H, H-3), 4.97 (t, 2
H, NH), 4.06–4.19 (m, 6 H, H-5, H-6, H-6%),
3.16–3.20 (m, 4 H, CH2), 2.10 (s, 6 H, CH3),
2.05 (s, 6 H, CH3), 2.04 (s, 6 H, CH3), 2.00 (s,
6 H, CH3), 1.42 (m, 4 H, CH2), 1.26 (m, 16 H,
CH2); 13C NMR (CDCl3): 170.31, 170.12,
169.91 and 169.62 (CH3CO), 153.73 (CONH),
93.19 (C-1), 71.37 (C-5), 70.90 (C-3), 67.98
(C-2), 66.91 (C-4), 60.97 (C-6), 41.18, 29.63,
29.48, 29.16, 26.91 and 26.67 (CH2), 20.70,
20.63, 20.60 and 20.52 (CH3CO). Anal. Calcd
for C42H64N2O22: C, 53.16; H, 6.80; N, 2.95;
O, 37.09. Found: C, 53.20; H, 7.19; N, 2.68;
O, 37.00.
General procedure for the synthesis of asym-
metrical bola-amphiphiles.—A solution of
2,3,4,6-tetra-O-acetyl-b- -galactopyranose
D
Bis[O - (2,3,6,2%,3%,4%,6% - hepta - O - acetyl - i-
lactosyl)] 1,6-hexanediylbis(carbamate) (3).
(0.5 mmol) in toluene was added drop by drop
to alkyl diisocyanate (1 mmol) and DABCO
in toluene. The mixture was stirred at rt for 48
h, then 2,3,6,2%,3%,4%,6%-hepta-O-acetyl-b-lac-
tose was introduced. The mixture was stirred
at rt for 48 h. After evaporation to dryness,
the mixture was chromatographed on silica gel
with 3:2 EtOAc–hexane.
White powder (60%); mp 45–46 °C; [h]D20
+
1
3.9° (c 1.0, CH2Cl2); H NMR (CDCl3): 5.61
(d, 2 H, J1,2 8.32, H-1), 5.34 (d, 2 H, H-4%),
5.24 (t, 2 H, H-2), 4.91–5.14 (m, 6 H, H-2%,
H-1%, H-3%), 4.88 (t, 2 H, NH), 4.43–4.49 (m, 4
H, H-3, H-5), 4.03–4.17 (m, 6 H, H-4, H-6%,
H-6%%), 3.76–3.89 (m, 6 H, H-5%, H-6, H-6%),
3.13–3.18 (m, 4 H, CH2), 2.11 (s, 6 H, CH2),
2.07 (s, 6 H, CH3), 2.05 (s, 6 H, CH3), 2.04 (s,
6 H, CH3), 2.02 (s, 6 H, CH3), 2.01 (s, 6 H,
CH3), 1.97 (s, 6 H, CH3), 1.48 (m, 4 H, CH2),
1.31 (s, 4 H, CH2); 13C NMR (CDCl3): 170.22,
170.14, 170.00, 169.80, 169.56 and 169.00
(CH3CO), 153.73 (CONH), 100.95 (C-1%),
92.63 (C-1), 71.02 (C-2), 75.73 (C-3), 73.31
(C-5), 72.71 (C-4), 70.75 (C-5%), 70.66 (C-3%),
69.08 (C-2%), 66.66 (C-4%), 61.81 (C-6), 60.82
(C-6%), 40.92, 29.43 and 26.14 (CH2), 20.79,
20.76, 20.67, 20.63, 20.61, 20.55 and 20.49
(CH3CO). Anal. Calcd for C60H84N2O38: C,
50.01; H, 5.87; N, 1.94. Found: C, 49.73; H,
5.75; N, 1.89.
O-(2,3,4,6-Tetra-O-acetyl-i- -galactopyr-
D
anosyl)-O-(2,3,6,2%,3%,4%,6%-hepta-O-acetyl-i-
lactosyl) 1,6-hexanediylbis(carbamate) (5).
White powder (38%); mp 79–81 °C; [h]D20
+
1
8.6° (c 1.0, CH2Cl2); H NMR (CDCl3): 5.64
(d, 1 H, J1,2 8.3), 5.62 (d, 1 H, J 8.6), 5.35 (d,
1 H), 5.43 (d, 1 H), 4.93–5.29 (m, 8 H),
4.44–4.49 (m, 2 H), 4.03–4.17 (m, 6 H), 3.78–
3.90 (m, 3 H), 3.13–3.20 (m, 4 H), 2.12 (s, 3
H), 2.10 (s, 3 H), 2.07 (s, 3 H), 2.05 (s, 3 H),
2.04 (s, 3 H), 2.01 (s, 3 H), 2.00 (s, 3 H), 1.99
(s, 3 H), 1.97 (s, 3 H), 1.42 (m, 4 H), 1.26
(s, 4 H); 13C NMR (CDCl3): 170.24, 170.14,
170.12, 170.06, 169.93, 169.79, 169.65, 169.56,
169.45, 169.02 and 169.00 (CH3CO), 153.82
(CONH), 153.72 (CONH), 100.95 (C-1%),
93.24 (C-1), 92.64 (C-1), 75.74 (C-3), 73.30
(C-5), 72.70 (C-4), 71.39 (C-5), 71.02 (C-2),
70.91 (C-3), 70.75 (C-5%), 70.75 (C-3%), 69.08
(C-2%), 67.99 (C-2), 66.90 (C-4), 66.68 (C-4%),
61.83 (C-6), 60.97 (C-6), 60.86 (C-6%), 40.89,
29.50 and 26.08 (CH2), 20.94, 20.85, 20.79,
20.75, 20.72, 20.66, 20.64, 20.62, 20.52,
20.50 and 20.48 (CH3CO), Anal. Cald for
Bis[O-(2,3,6,2%,3%,4%,6%-hepta-O-acetyl-i-lac-
tosyl)] 1,12-dodecanediylbis(carbamate) (4).
White powder (50%); mp 60–61 °C; [h]D20
+
1
34.5° (c 1.0, CH2Cl2); H NMR (CDCl3): 5.61
(d, 2 H, J1,2 8.32, H-1), 5.34 (d, 2 H, H-4%),
5.24 (t, 2 H, H-2), 4.91–5.14 (m, 6 H, H-2,
H-1%, H-3%), 4.43–4.49 (m, 4 H, H-3, H-5),
4.03–4.17 (m, 6 H, H-4, H-6%, H-6%%), 3.76–

C. Prata et al. / Carbohydrate Research 321 (1999) 15–23
21
169.23 (CH3CO), 128.49 and 128.06 (Ph),
100.91 (C-1%), 89.93 (C-1), 76.40 (C-3), 74.47
(C-5), 73.21 (C-4), 71.53 (C-2), 71.05 (C-5%),
70.58 (C-3%), 69.22 (C-2%), 66.57 (C-4), 61.01
(C-6), 60.47 (C-6%), 41.09, 33.93, 29.88, 29.39,
29.28, 29.16, 29.01, 26.99, 26.68 and 24.72
(CH2), 20.90, 20.83, 20.74, 20.66, 20.63, 20.56
and 20.51 (CH3CO). Anal. Calcd for
C45H64N2O20: C, 56.72; H, 6.76; N, 2.94.
Found: C, 56.51; H, 6.82; N, 3.01.
C48H68N2O30: C, 50.00; H, 5.94; N, 2.43.
Found: C, 49.71; H, 5.87; N, 2.31.
O-(2,3,4,6-Tetra-O-acetyl-i- -galactopyr-
D
anosyl) O-(2,3,6,2%,3%,4%,6%-hepta-O-acetyl-i-
lactosyl) 1,12-dodecanediylbis(carbamate) (6).
White powder (20%); mp 90–92 °C; [h]D20
+
1
26.4° (c 1.0, CH2Cl2); H NMR (CDCl3): 5.65
(d, 1 H, J1,2 8.5), 5.63 (d, 1 H, J1,2 8.5), 5.43
(d, 1 H), 5.34 (d, 1 H), 4.88–5.26 (m, 8 H),
4.42–4.52 (m, 2 H), 4.03–4.23 (m, 6 H), 3.74–
3.88 (m, 3 H), 3.16–3.20 (m, 4 H), 2.11 (s, 3
H), 2.07 (s, 3 H), 2.05 (s, 3 H), 2.04 (s, 3 H),
2.02 (s, 3 H), 2.01 (s, 3 H), 1.97 (s, 3 H), 1.42
(m, 4 H), 1.27 (s, 16 H); 13C NMR (CDCl3):
170.34, 170.22, 170.14, 170.07, 170.00, 169.80,
169.65, 169.56, 169.45, 169.01 and 169.00
(CH3CO), 153.70 (CONH), 153.61 (CONH),
100.95 (C-1%), 93.22 (C-1), 92.60 (C-1), 75.77
(C-3), 73.27 (C-5), 72.69 (C-4), 71.39 (C-5),
71.02 (C-2), 70.91 (C-3), 70.75 (C-5%), 70.65
(C-3%), 69.05 (C-2%), 67.97 (C-2), 66.87 (C-4),
66.64 (C-4%), 61.87 (C-6), 60.95 (C-6), 60.84
(C-6%), 41.19, 38.76, 30.38, 29.70, 29.63, 29.48,
29.20, 28.94, 26.67, 25.36, 23.77 and 22.98
(CH2), 20.96, 20.86, 20.79, 20.76, 20.73, 20.67,
20.63, 20.61, 20.55, 20.50 and 20.49 (CH3CO).
Anal. Calcd for C54H80N2O30: C, 52.42; H,
6.51; N, 2.26. Found: C, 52.35; H, 6.60; N,
2.21.
N-(2,3,4,6-Tetra-O-acetyl-i- -galactopyr-
D
anosyl) - N% - [10 - (2,3,6,2%,3%,4%,6% - hepta - O-
acetyl - i - lactosylaminocarbonyl)decan - 1 - yl]-
thiourea (16). To a mixture of 15 (0.63 g, 0.66
mmol) in MeOH was added Pd–C (40 mg).
The solution was saturated with hydrogen at
8×105 Pa. After 4 h, the reaction mixture was
filtered and the filtrate was concentrated under
reduced pressure. The syrup obtained was re-
acted with isothiocyanate 2,3,4,6-tetra-O-
acetyl-b- -galactopyranosyl (0.56 g, 0.66
D
mmol) in the presence of DABCO in toluene.
The solution was stirred 18 h at rt. The sol-
vent was removed and the residue was then
chromatographed on silica gel with 3:2
EtOAc–hexane. It was obtained as a white
powder (47%); mp 74–76 °C; [h]2D0 +44.9° (c
1.0, CH2Cl2); 1H NMR (CDCl3): 5.85 (d, 1 H),
5.36–5.77 (m, 6 H), 4.94–5.24 (m, 3 H), 4.78–
4.89 (m, 5 H), 4.65 (d, 1 H), 4.43–4.52 (m, 2
H), 4.03–4.23 (m, 6 H), 3.74–3.88 (m, 3 H),
3.16–3.20 (m, 2 H), 2.35 (m, 2 H), 2.11 (s, 3
H), 2.07 (s, 3 H), 2.05 (s, 3 H), 2.04 (s, 3 H),
2.02 (s, 3 H), 2.01 (s, 3 H), 1.97 (s, 3 H), 1.42
(m, 4 H), 1.26 (s, 12 H); 13C NMR (CDCl3):
178.70 (CONH), 170.34, 170.22, 170.13,
170.07, 170.00, 169.76, 169.65, 169.26, 169.19,
169.07 and 169.00 (CH3CO), 165.34 (NHC-
SNH), 101.03 (C-1%), 90.09 (C-1), 89.21 (C-1),
76.26 (C-3), 74.51 (C-5), 73.08 (C-4), 71.41
(C-2), 71.39 (C-5), 70.91 (C-3), 70.75 (C-5%),
70.65 (C-3%), 69.05 (C-2%), 67.97 (C-2), 66.87
(C-4), 66.64 (C-4%), 61.87 (C-6), 60.95 (C-6),
60.84 (C-6%), 20.96, 20.86, 20.79, 20.76, 20.73,
20.67, 20.63, 20.61, 20.55, 20.50 and 20.49
(CH3CO), 41.19, 38.76, 30.38, 29.70, 29.63,
29.20, 26.67, 25.36, 23.77 and 22.98 (CH2).
Anal. Calcd for C52H77N3O27S: C, 51.16; H,
6.37; N, 3.47. Found: C, 50.98; H, 6.62; N,
3.30.
N-(2,3,6,2%,3%,4%,6%-Hepta-O-acetyl-i-lac-
topyranosyl) 11-benzyloxycarbonylamino-un-
decanamide (15).
A
mixture of ZNH-
(CH2)10CO2H (13) (0.169 g, 0.5 mmol),
2,3,6,2%,3%,4%,6%-hepta-O-acetyl-b-lactosyl isoth-
iocyanate (14) (0.340 g, 0.5 mmol) and
DABCO in toluene was stirred 8 h at rt. The
solvent was removed and the residue was then
chromatographed on silica gel with 3:2 hex-
ane–EtOAc. It was obtained as a white pow-
der (40%); mp 75–77 °C; [h]2D0 +29.2° (c 1.0,
1
CH2Cl2); H NMR (CDCl3): 7.14–7.35 (m, 5
H), 6.26 (d, 1 H), 5.43–5.51 (m, 2 H), 5.35 (d,
1 H), 4.79–5.23 (m, 4 H), 4.65 (d, 1 H, J1,2
7.67), 4.42–4.52 (m, 2 H), 3.76–4.29 (m, 6 H),
3.13–3.16 (m, 1 H), 2.31 (m, 1 H), 2.10 (s, 3
H), 2.06 (s, 3 H), 2.05 (s, 3 H), 2.04 (s, 3 H),
2.02 (s, 3 H), 2.01 (s, 3 H), 1.97 (s, 3 H), 1.62
(m, 2 H), 1.46 (m, 2 H), 1.26 (m, 12 H); 13C
NMR (CDCl3): 178.16 (CONH), 170.50,
170.35, 170.27, 169.89, 169.78, 169.36 and

22
C. Prata et al. / Carbohydrate Research 321 (1999) 15–23
General O-deacetylation procedure.—The
(C-5%), 77.06 (C-3), 76.44 (C-5), 74.88 (C-2),
73.64 (C-3%), 72.53 (C-2%), 70.35 (C-4%), 62.60
(C-6%), 61.46 (C-6), 41.91, 32.80, 32.71, 32.59,
32.31 and 27.22 (CH2). Anal. Calcd for
C38H68N2O24: C, 48.69; H, 7.26; N, 2.99.
Found: C, 48.78; H, 7.71; N, 3.02.
fully protected glycoside was dissolved in dry
MeOH and treated with a catalytic amount of
NaOMe. After 2 h at rt, the mixture was
neutralized with Amberlite IRC 50 (H+ form),
filtered and evaporated. The compounds ob-
tained were analytically pure, in almost quan-
titative yield.
O-(i-D
-Galactopyranosyl)
O-(i-lactosyl)
1,6-hexanediylbis(carbamate) (11). White hy-
groscopic powder; [h]2D0 +6.6° (c 1.0, MeOH);
1H NMR (CD3OD): 5.35 (d, 1 H, J1,2 7.9),
5.30 (d, 1 H, J1,2 8.6), 3.30–4.32 (m, 21 H),
Bis[O-(i- -galactopyranosyl)] 1,6-hexane-
D
diylbis(carbamate) (7). White hygroscopic
1
powder; [h]2D0 +6.9° (c 1.0, MeOH); H NMR
13
(CD3OD): 5.25 (d, 2 H, J1,2 7.9), 3.83 (d, 2 H),
3.56–3.70 (m, 10 H), 3.31 (dd, 2 H), 3.11 (t, 4
H), 1.50 (m, 4 H), 1.31 (s, 4 H); 13C NMR
(CD3OD): 157.31 (CONH), 97.25 (C-1), 77.12
(C-5), 74.84 (C-3), 71.47 (C-2), 70.06 (C-4),
62.30 (C-6), 41.93, 32.76 and 27.65 (CH2).
Anal. Calcd for C20H36N2O14: C, 45.40; H,
6.81; N, 5.30. Found: C, 45.21; H, 7.02; N,
5.15.
3.10 (t, 4 H), 1.46 (m, 4 H), 1.29 (s, 4 H); C
NMR (CD3OD): 157.80 and 157.75 (CONH),
104.94 (C-1% Lac), 97.31 (C-1 Gal), 96.61 (C-1
Lac), 79.87 (C-4 Lac), 77.19 (C-5% Lac), 77.15
(C-5 Gal), 77.06 (C-3 Lac), 76.44 (C-5 Lac),
74.88 (C-2 Lac), 74.81 (C-3 Gal), 73.64 (C-3%
Lac), 72.53 (C-2% Lac), 71.44 (C-2 Gal), 70.35
(C-4% Lac), 70.10 (C-4 Gal), 62.60 (C-6% Lac),
62.27 (C-6 Gal), 61.46 (C-6 Lac), 41.89, 32.50
and 27.08 (CH2). Anal. Calcd for
C26H46N2O19: C, 45.19; H, 6.66; N, 4.05.
Found: C, 45.6; H, 6.80; N, 4.15.
Bis[O-(i-
D
-galactopyranosyl)]
1,12-dode-
canediylbis(carbamate) (8). White hygroscopic
powder; [h]2D0 +9.6° (c 1.0, MeOH); H NMR
1
(CD3OD): 5.25 (d, 2 H, J1,2 7.9), 3.83 (d, 2 H),
3.56–3.70 (m, 10 H), 3.31 (dd, 2 H), 3.11 (t, 4
H), 1.50 (m, 4 H), 1.31 (s, 16 H); 13C NMR
(CD3OD): 157.26 (CONH), 97.31 (C-1), 77.15
(C-5), 74.81 (C-3), 71.44 (C-2), 70.10 (C-4),
62.27 (C-6), 41.98, 33.16, 32.63, 32.48, 27.91
and 27.67 (CH2). Anal. Calcd for
C26H36N2O14: C, 52.00; H, 6.04; N, 4.66.
Found: C, 51.76; H, 6.14; N, 4.58.
O-(i-D
-Galactopyranosyl)
O-(i-lactosyl)
1,12-dodecanediylbis(carbamate) (12). White
hygroscopic powder; [h]2D0 +14.7° (c 1.0,
MeOH); 1H NMR (CD3OD): 5.35 (d, 1 H, J1,2
7.9), 5.30 (d, 1 H, J1,2 8.6), 3.28–4.35 (m, 21
H), 3.10 (t, 4 H), 1.46 (m, 4 H), 1.29 (s, 16 H);
13C NMR (CD3OD): 157.70 and 157.61
(CONH), 104.94 (C-1% Lac), 97.33 (C-1 Gal),
96.63 (C-1 Lac), 79.86 (C-4 Lac), 77.19 (C-5%
Lac), 77.17 (C-5 Gal), 77.09 (C-3 Lac), 76.44
(C-5 Lac), 74.85 (C-2 Lac), 74.80 (C-3 Gal),
73.64 (C-3% Lac), 72.53 (C-2% Lac), 71.43 (C-2
Gal), 70.35 (C-4% Lac), 70.07 (C-4 Gal), 62.60
(C-6% Lac), 62.21 (C-6 Gal), 61.41 (C-6 Lac),
41.89, 40.76, 32.38, 31.70, 31.63, 31.48, 31.20,
30.64, 27.67, 26.36, 24.77 and 23.98 (CH2).
Anal. Calcd for C32H58N2O19: C, 49.58; H,
7.49; N, 3.61. Found: C, 49.75; H, 7.61; N,
3.75.
Bis[O-(i-lactosyl)] 1,6-hexanediylbis(carba-
mate) (9). White hygroscopic powder; [h]D20
1
+2.5° (c 1.0, MeOH); H NMR (CD3OD):
5.35 (d, 2 H, J1,2 8.2), 4.36 (d, 2 H), 3.29–3.95
(m, 26 H), 3.10 (t, 4 H), 1.46 (m, 4 H), 1.29 (s,
4 H); 13C NMR (CD3OD): 157.61 (CONH),
104.95 (C-1%), 96.60 (C-1), 79.87 (C-4), 77.18
(C-5%), 77.05 (C-3), 76.42 (C-5), 74.89 (C-2),
73.64 (C-3%), 72.53 (C-2%), 70.30 (C-4%), 62.60
(C-6%), 61.46 (C-6), 41.92, 32.33 and 27.24
(CH2). Anal. Calcd for C32H56N2O24: C, 45.07;
H, 6.62; N, 3.28. Found: C, 44.80; H, 6.82; N,
3.15.
N - (i -
D
- Galactopyranosyl) - N% - [10 - (i-
lactosylaminocarbonyl)decan-1-yl]thiourea (17).
White powder; mp 133–135 °C; [h]2D0 +19.6°
(c 1.0, CH2Cl2); H NMR (CD3OD): 3.29–4.9
1
Bis[O-(i-lactosyl)]
1,12-dodecanediylbis-
(carbamate) (10). White hygroscopic powder;
[h]2D0 +17.0° (c 1.0, MeOH); 1H NMR
(CD3OD): 5.30 (d, 2 H, J1,2 8.2), 3.29–3.95
(m, 28 H), 3.10 (t, 4 H), 1.46 (m, 4 H), 1.29 (s,
16 H); 13C NMR (CD3OD): 157.66 (CONH),
104.94 (C-1%), 96.61 (C-1), 79.87 (C-4), 77.19
(m, 26 H), 3.20 (t, 2 H), 3.10 (t, 4 H), 1.46 (m,
4 H), 1.29 (s, 12 H); 13C NMR (CD3OD):
177.75 (CONH), 171.59 (NHCSNH), 104.94
(C-1% Lac), 85.82 (C-1 Gal), 81.60 (C-1 Lac),
78.86 (C-4 Lac), 78.17 (C-2 Gal), 77.19 (C-5%
Lac), 77.09 (C-3 Lac), 76.44 (C-5 Lac), 75.91

C. Prata et al. / Carbohydrate Research 321 (1999) 15–23
23
[2] J.H. Fuhrhop, D. Fritsch, Acc. Chem. Res., 19 (1986)
130–137.
[3] J.H. Fuhrhop, H.H. David, J. Mathieu, U. Liman, H.J.
Winter, E. Bockema, J. Am. Chem. Soc., 108 (1986)
1785–1791.
[4] P. Lo Nostro, G. Briganti, S.H. Chen, J. Colloid Interf.
Sci., 142 (1991) 214–223.
[5] J.H. Fuhrhop, H. Tank, Chem. Phys. Lipids, 43 (1987)
193–213.
(C-3 Gal), 74.85 (C-2 Lac), 73.64 (C-3% Lac),
72.53 (C-2% Lac), 71.65 (C-4 Gal), 70.80 (C-5
Gal), 70.35 (C-4% Lac), 62.95 (C-6 Gal), 62.60
(C-6% Lac), 61.41 (C-6 Lac), 41.90, 40.75,
33.31, 32.76, 32.62, 32.20, 27.57, 26.26, 24.47
and 23.28 (CH2). Anal. Calcd for
C30H55N3O16S: C, 48.34; H, 5.95; N, 3.76.
Found: C, 47.99; H, 5.86; N, 3.74.
[6] R. Garelli-Calvet, F. Brisset, I. Rico, A. Lattes, Synth.
Commun., 23 (1993) 35–44.
[7] F. Brisset, R. Garelli-Calvet, J. Azema, C. Chebli, I.
Rico-Lattes, A. Lattes, A. Moisand, New J. Chem., 20
(1996) 595–605.
Acknowledgements
[8] G. Excoffier, D. Gagnaire, J.P. Utille, Carbohydr. Res.,
39 (1975) 368–373.
[9] C. Prata, N. Mora, J.M. Lacombe, J. Maurizis, B. Pucci,
Tetrahedron Lett., 38 (1997) 8859–8862.
[10] C. Prata, N. Mora, J.M. Lacombe, J. Maurizis, B. Pucci,
Carbohydr. Res., 321 (1999) 4–14.
[11] M.J. Camarasa, P. Fernandez-Resa, M.T. Garcia-Lopez,
G. de Las Heras, P.P. Mendez-Castrillon, A. San Felix,
Synthesis, (1984) 509–510.
[12] S. Mun˜oz, J. Malle´n, A. Nakano, Z. Chen, I. Gay, L.
Echegoyen, G.W. Gokel, J. Am. Chem. Soc., 115 (1993)
1705–1711.
We thank the Ambassade de France au
Portugal, la Junta Nacional de Investigac¸a˜o
Cient´ıfica e Tecnolo´gica and the Conseil Sci-
entifique de l’Universite´ d’Avignon for grants
to C. Prata.
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