Syntheses of optically active monomers and copolymers derived from protected 6′-O-acryloyl sucroses

Article abstract of DOI:10.1055/s-2002-33120

Selectively 6′-O-monoacrylated monomers of fully protected sucrose moieties were synthesized by a multistep route. Chiral copolymers were prepared from these monomers with styrene or methyl methacrylate using radical initialization with azobisisobutyronitrile (AIBN). The quantitative incorporation of substoichiometric components was verified. Copolymers composition and purity were reliably analyzed by ¹H NMR and SEC.

Full text of DOI:10.1055/s-2002-33120

PAPER
1407
Syntheses of Optically Active Monomers and Copolymers Derived from
Protected 6 -O-Acryloyl Sucroses
P
rotecte
d
6 -O
-Acryloy
.
l
Sucroses Teresa Barros,* Fernando Siñeriz
Departamento de Química, Centro de Química Fina e Biotecnologia, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa,
Quinta da Torre, 2829-516 Caparica, Portugal
Fax +351(21)2948550; E-mail: mtbarros@dq.fct.unl.pt
Received 4 February 2002; revised 24 April 2002
developed21 a multistep procedure22 that allowed us to ob-
Abstract: Selectively 6 -O-monoacrylated monomers of fully pro-
tain selectively the unprotected 6 -hydroxyl and we have
prepared vinyl sucrose derivatives from this intermediate.
Using this strategy, we were able to control the regioselec-
tected sucrose moieties were synthesized by a multistep route.
Chiral copolymers were prepared from these monomers with sty-
rene or methyl methacrylate using radical initialization with azobi-
sisobutyronitrile (AIBN). The quantitative incorporation of tive monofunctionalization of the sugar in order to form a
substoichiometric components was verified. Copolymers composi-
monomer which could be converted into pure linear poly-
mers, avoiding the presence of mixtures of mono- and (or)
tion and purity were reliably analyzed by 1H NMR and SEC.
Key words: carbohydrates, monoacrylates, regioselectivity, free
radical polymerization, polymers
multi-substituted modified sucrose molecules that results
in cross-linked polymerization.2,11
The properties of these polymers are dependent on the di-
verse substituents on the sugar,1 and we have prepared
several sucrose monomers protected with different
groups. These sugar monomers, containing a unique poly-
merizable double bond, were subjected to free-radical po-
lymerization using azobisisobutyronitrile (AIBN)
affording optically active copolymers.
Vinyl sugars can be easily copolymerized with various
comonomers and constitute polymers of a special struc-
tural type. They have potential for modifying and improv-
ing several properties of conventional polymer materials
namely the introduction of chirality, superior biodegrad-
ability and biocompatibility.1,2 Extensive studies on the
syntheses of vinyl monomers and polymers of saccharides
have been reported.3–7
Here we report the selective preparation of three new 6 -
O-methacryloyl esters of protected sucroses and the syn-
thesis of new crotonyl derivatives monomers of sucrose.
The study of the copolymerization of one monomer with
styrene or methyl methacrylate as well as the characteriza-
tion of the corresponding sucrose polymers is also de-
scribed.
The most common approach to these compounds, in order
to attain the monomer susceptible to polymerization, is by
the attachment of an unsaturated component to the sugar.
This linkage is usually in the form of an ether, ester or
amido group.4
The first step to our targets consisted in a regioselective si-
lylation of the 6 -hydroxyl group (Scheme 1) of the su-
crose using tert-butyldiphenylchlorosilane (TBDPSCl)
according to the methods described earlier,22 followed by
an acylation or alkylation of the remaining hydroxyl
In the context of the use of sucrose as a chemical raw
material8,9 there is an increasing interest in this chemistry
field10,11 and several studies in this area can be found dur-
ing the last decade.8,12,13
The hydroxyl positions where the vinyl group has been re- groups.
gioselectivity introduced in the sucrose molecule have tra-
The monosilylated sucrose 122 was reacted with three dif-
ditionally been the primary hydroxyl or the 4-OH on the
glucose moiety12,13or the 1 -OH of the fructose moi-
ety.9,14A high degree of regioselectivity can be achieved
by the enzymatic approach9,14 although some disadvan-
tages and limitations can be found in the use of enzymes
(low stability of the enzymes in organic solvents or the
correct choice of agents for introducing the unsatura-
tion).11 To our knowledge, ester sucrose monomers have
never been prepared chemically at the 6 -O position for
building vinyl polymers.
ferent agents, namely methyl iodide (MeI), benzoyl chlo-
ride (BzCl) and 3,4,5-tri-O-methylgalloyl chloride,
leading respectively to the compounds 2,3,22 and 4. Be-
cause of a slight instability of the TBDPS protecting
group under strongly basic conditions (KOH, DMSO), re-
quired for the alkylation,23 we have always obtained the
expected octamethylsucrose as a byproduct during the
preparation of 2. Good yields have been obtained in the
acylation step for the synthesis of 3 in the presence of 4-
dimethylaminopyridine (4-DMAP), or in the presence of
Several strategies have been employed to obtain sucrose tetramethylethylenediamine (TMEDA) for the synthesis
with the 6 -OH free for functionalization.15–20 We have of 4.21,24 To prepare this latter product, it has been neces-
sary to heat at reflux temperature in order to protect all the
hydroxyl groups, otherwise the hexaacylated sugar was
isolated, being unprotected at the 2-OH.
Synthesis 2002, No. 10, 30 07 2002. Article Identifier:
1437-210X,E;2002,0,10,1407,1411,ftx,en;T01602SS.pdf.
© Georg Thieme Verlag Stuttgart · New York
ISSN 0039-7881

1408
M. T. Barros, F. Siñeriz
PAPER
In the 1H NMR spectra of all these compounds two signals
have been attributed to the double bond: singlet at 6.14
ppm and triplet at 5.55 ppm for the compounds with the
methacrylic moiety (8,9 and 10); and for those com-
pounds with the crotonic moiety (11,12 and 13) a double
quadruplet or multiplet at 6.93 ppm and a doublet at 5.80
ppm. We could also assign the allylic methyl groups of the
molecules at 1.90 ppm (s for 8–10) and 1.75 ppm (d for
11–13). The presence of a signal at about 18 ppm in each
of the homodecoupled 13C NMR spectra of these six com-
pounds, confirmed the presence of the new methyl group.
OH
OH
OH
OH
O
O
HO
HO
HO
HO
i)
OH
OH
O
O
HO
HO
O
O
OH
OTBDPS
122
OH
OH
ii), iii) or iv)
OR
OR
OR
OR
O
O
RO
RO
RO
RO
v), vi) or vii)
OH
OR
OR
O
O
RO
RO
O
O
OTBDPS
73%
OR
OR
5 R=Me
6 R=Bz21
98%
73%
2 R=Me
3 R=Bz22
The polymerizability (homo- and copolymerization) of
monomer 9 has been examined in the presence of AIBN
as free-radical initiator in toluene at 70 °C. Unfortunately,
homopolymerization of compound 9 failed to give poly-
mers of high molar mass as did the copolymerization with
acrylonitrile. We found that copolymerization of com-
pound 9 (Table) with styrene or methyl methacrylate af-
forded the expected poly(sucrose 6 -acrylate) after 24
hours of reaction and precipitation with ethanol (0 °C). A
study of the effect of varying the stoichiometry of the
comonomers on the sugar incorporation in the final
copolymers has been carried out. As a result, we obtained
several copolymers with diverse degrees of protected su-
crose appended. This resulted in different physical prop-
erties such as optical rotations. As expected this lowered
progressively with the larger participation of the non-opti-
cally active comonomer.
4 R=3,4,5-(OMe)3-C6H2-CO 82%
7 R=3,4,5-(OMe)3-C6H2-CO
Scheme 1 i) TBDPSCI, py; ii) Mel, KOH, DMSO, 73%; iii) BzCl,
py, DMAP; iv) 3,4,5-(OMe)3-C6H2COCl, MeCN, TMEDA, 82%; v)
Bu4NF, THF, 98%; vi) 1% Br2/MeOH; vii) 0.1% Br2/MeOH, 73% +
22% initial
Selective deprotection of the silyl group, with TBAF at
room temperature or with Br2/MeOH at reflux, furnished,
compounds 5,6,21 and 7 (73% yield, 22% of the starting
material was recovered), respectively, from 2,3 and 4, af-
ter column chromatography. In the case of 6 or 7 migra-
tions of the acyl groups were avoided by the use of
bromine (Br2) in methanol (MeOH) at reflux, a recently
developed methodology.25
Esterification reactions of the 6 -hydroxyl free sucrose
were carried out by treating the sugars 5–7, in dichloro-
methane in the presence of triethylamine at room temper-
ature with the appropriate anhydride as reagent, to give
the expected compounds 8–13 (Scheme 2) in good yields.
Poly(sucrosyl) composition has been determined from the
1H NMR spectra of the copolymers. The structures have
been verified by comparing the peak areas of both the me-
thylene and methyl protons of the polymer chain (0.8–2.2
ppm), as well as the methoxy protons, when the comono-
mer is methyl methacrylate, with the 14 protons area of
the sucrose units. We have noticed in the 13C NMR spec-
trum of the copolymer with methyl methacrylate, the pres-
ence of two different groups of carbonyl signals, one from
the sugar ester moiety and the other from the carbonyls of
the comonomer.
Some problems were encountered in the purification of
the monomers, particularly in the case of 13, where traces
of impurities were difficult to separate from the required
compound.
OR
OR
O
RO
RO
OR
Data obtained by Size Exclusion Chromatography (SEC)
analysis, revealed monomodal distributions. Copolymer
molecular weights (Mw), estimated by the same method,
were in a similar range of values to those of similar copol-
ymers.8,12 Polydispersity values (Mw/Mn) revealed a cer-
tain degree of heterogeneity under the adopted conditions
of work. Copolymers were soluble in classical organic
solvents and insoluble in water as would be expected for
a fully capped sugar.
O
O
RO
O
O
OR
i)
8 R=Me
9 R=Bz
76%
80%
5, 6, 7
10 R=3,4,5-(OMe)3-C6H2-CO 80%
ii)
OR
OR
In summary, some 6 -hydroxyl free (otherwise protected)
sucrose derivatives have been prepared. Selective incor-
poration of unsaturated ester groups for the preparation of
sucrose monomers was accomplished through its reaction
with the corresponding symmetrical anhydrides in the
presence of DMAP as catalyst. As a final point, new chiral
copolymers containing sucrose were synthesized by radi-
cal polymerization and some of their physical properties
were determined.
O
RO
RO
OR
O
O
RO
O
O
OR
11 R=Me
12 R=Bz
65%
80%
13 R=3,4,5-(OMe)3-C6H2-CO 81%
Scheme 2 i) methacrylic anhydride, Et3N, CH2Cl2, DMAP; ii) cro-
tonic anhydride, Et3N, CH2Cl2, DMAP
Synthesis 2002, No. 10, 1407–1411 ISSN 0039-7881 © Thieme Stuttgart · New York

PAPER
Protected 6 -O-Acryloyl Sucroses
1409
Table Copolymerization of 9 with Styrene or Methyl Methacrylate in the Presence of Radical Initiator AIBN (toluene, 70 °C, 24 h)
c
d
Alkene
Yield (%)
Mw
[ ]D
styrene
0.25
1
0.017
0.091
0.083
0.063
51
84
65
83
10763
9670
2.67
2.23
1.62
1.62
+ 8.4 (c = 1.0, CHCl3)
+22.7 (c = 1.5, CHCl3)
+21.1 (c = 1.6, CHCl3)
+17.0 (c = 1.0, CHCl3)
methyl methacrylate
methyl methacrylate
methyl methacrylate
0.50
0.25
11970
18127
a Initial molar ratio of monomers.
b Mole ratio of comonomer units in copolymer, determined by 1H NMR.
c Determined by SEC with DMF as solvent using polyethyleneglycols as standards.
d Monomer 9: [ ]D +37.8 (c = 1.1, CHCl3).
Reagents and solvents were purified before use.26 All reactions were
run under a positive pressure of dry argon except for the preparation
of 2,6 and 7. Flash chromatography was performed on silica gel
(Macherey-Nagel Kieselgel 60 M). Preparative TLC was performed
on glass plates coated with 1 mm of silica gel (Macherey-Nagel,
Kieselgel DGF254). Analytical TLC: Aluminum-backed silica gel
(Merck 60 F254). Optical rotations were measured at 20 °C on an
AA-1000 polarimeter (0.5 dm cell). NMR spectra were recorded on
a Bruker AMX-400 spectrometer (1H at 400 MHz and 13C at 100
MHz) in CDCl3with chemical shift values ( ) in ppm downfield
from TMS. Some compound signals were assigned by performing
Anal. Calcd for C35H54O11Si (678.34): C, 61.92; H, 8.02. Found: C,
61.92; H, 8.18.
6 -O-tert-Butyldiphenylsilyl-2,3,4,6,1 ,3 ,4 -hepta-O-(tri-O-me-
thylgalloyl)sucrose (4)
To compound 1 (0.40 g, 0.7 mmol) in MeCN (10 mL) was added
TMEDA (1.17 mL, 0.90 g, 7.7 mmol) under stirring. The mixture
was cooled to 0 °C and a solution of tri-O-methylgalloyl chloride
(1.78 g, 7.7 mmol) in MeCN (5 mL) was added. The temperature
was allowed to rise, then stirred overnight at reflux. After neutral-
ization by a solution of phosphate buffer (pH 7, 35 mL), a white pre-
cipitate appeared. The precipitate was filtered off and washed with
H2O (15 mL). Flash chromatography (EtOAc–hexane, 2:1) of the
remaining solid yielded 4 (1.10 g, 82%) as a white powder; [ ]D
+23.3 (c = 1.2, CHCl3).
1H NMR (CDCl3): = 7.69 (m, 4 H, Ar), 7.32–6.98 (7 s, 14 H, Ar),
7.31 (m, 6 H, Ar), 6.27 (m, 2 H, H-1, H-4 ), 6.02 (t, 1 H, J = 10.0
Hz, H-3), 5.84 (d, 1 H, J = 7.6 Hz, H-3 ), 5.74 (t, 1 H, J = 10.0 Hz,
H-4), 5.31 (dd, 1 H, J = 10.2, 3.6 Hz, H-2), 4.75 (d, 1 H, J = 11.8
Hz, H-1 a), 4.57 (d, 1 H, J = 10.0 Hz, H-5), 4.50 (d, 1 H, J = 11.6
Hz, H-1 b), 4.32 (ddd, 1 H, J = 7.6, 4.4, 4.2 Hz, H-5 ), 4.10 (m, 4 H,
2 H-6 and 2 H-6 ), 3.93–3.76 (11 s, 63 H, 21 CH3O), 1.01 (s, 9 H, t-
C4H9).
1
additional H-1H COSY and HMQC measurements on the same
spectrometer. SEC analyses were performed on a Knauer apparatus
supplied with two columns PL Gel Mixed (5 m) and pre-column
PL Gel; oven Eldec LH-150 and a refraction index detector. The
equipment was calibrated with polyethyleneglycol standards. De-
terminations were run at 70 °C using a flow of 1 mL/min for a con-
centration of the sample in DMF of 1% (w/w). Microanalyses were
performed by the IST analytical services in Lisbon using a combus-
tion apparatus.
6 -O-tert-Butyldiphenylsilyl-2,3,4,6,1 ,3 ,4 -hepta-O-methylsu-
crose (2)
To a suspension of KOH (2.70 g, 28.0 equiv, 48.2 mmol) in DMSO
(4 mL) at r.t. was added, after 30 min, compound 122 (1.00 g, 1.7
mmol), immediately followed by MeI (1.50 mL, 14.0 equiv, 24.1
mmol). The mixture was stirred for an additional 10 min. Then, H2O
(10 mL) was added and several extractions with CH2Cl2 (5 15
mL) were performed. The combined organic layers were dried
(Na2SO4), and the solvent was evaporated to afford a pale yellow oil
that was purified by flash column chromatography (EtOAc–hexane,
1:1) to yield 0.85 g (73%) of 2; [ ]D +41.5 (c = 1.5, CHCl3).
13C NMR (CDCl3): = 19.72 (CMe3), 27.29 [C(CH3)3], 56.69–
56.93 (CH3OAr), 61.51 (CH3OAr), 63.33, 63.76, 66.78 (C-6, C-1
and C-6 ), 69.54, 70.09, 71.53, 72.09 (C-2, C-3, C-4 and C-5),
74.62, 78.60 (C-3 and C-4 ), 81.09 (C-5 ), 90.30 (C-1), 104.18 (C-
2 ), 107.75–153.68 (Ar), 165.52, 165.69, 165.86, 166.86, 166.03,
166.24 (7 CO).
Anal. Calcd for C98H110O39Si (1940.03): C, 60.67; H, 5.71. Found:
C, 60.68; H, 5.81.
1H NMR (CDCl3): = 7.67 (m, 4 H, Ar), 7.38 (m, 6 H, Ar), 5.56 (d,
1 H, J = 3.6 Hz, H-1), 4.04 (t, 1 H, J = 7.2 Hz, H-3 ), 3.90 (t, 1 H,
J = 7.2 Hz, H-4 ), 3.89 (t, 1 H, J = 7.2 Hz, H-5 ), 3.88 (m, 2 H, 2 H-
6 ), 3.84 (m, 1 H, H-5), 3.60 (m, 1 H, H-1 a), 3.56, 3.51, 3.47, 3.44,
3.41, 3.39, 3.28 (7 s, 21 H, 7 CH3O), 3.49 (m, 1 H, H-6a), 3.38 (m,
1 H, H-3), 3.36 (m, 1 H, H-1 a), 3.33 (m, 1 H, H-6b), 3.18 (t, 1 H,
J = 9.6 Hz, H-4), 3.05 (dd, 1 H, J = 9.6, 3.6 Hz, H-2), 1.05 (s, 9 H,
t-C4H9).
13C NMR (CDCl3): = 19.04 (CMe3), 26.63 [C(CH3)3], 57.91,
58.25, 58.52, 58.99, 59.36, 60.06, 60.49 (7 CH3O), 64.96 (C-6 ),
70.25 (C-5), 70.92 (C-6), 74.18 (C-1 ), 79.20 (C-4), 80.83 (C-5 ),
81.41 (C-2), 83.00 (C-3), 84.15 (C-4 ), 85.60 (C-3 ) 89.01 (C-1),
104.07 (C-2 ), 127.71–135.70 (Ar).
2,3,4,6,1 ,3 ,4 -Hepta-O-methylsucrose (5)
To a solution of 2 (0.75 g, 1.1 mmol) under argon was added a 1.0
M solution of TBAF in THF (2.22 mL, 2.2 mmol). After stirring for
4 h, TLC (EtOAc) showed no traces of the starting material. Evap-
oration of the solvent followed by purification on silica gel (EtOAc)
gave the title compound 5 (0.49 g, 98%); [ ]D +46.7 (c = 1.3,
CHCl3).
1H NMR (CDCl3): = 5.46 (d, 1 H, J = 3.6 Hz, H-1), 4.07 (m, 1 H,
H-3 ), 4.04 (m, 1 H, H-4 ), 3.93 (m, 1 H, H-5 ), 3.89 (m, 1 H, H-5),
3.85 (m, 2 H, 2 H-6 ), 3.62, 3.53, 3.50, 3.49, 3.48, 3.42, 3.40 (7 s, 21
H, 7 CH3O), 3.62–3.40 (m, 5 H, H-3, 2 H-6 and 2 H-1 ), 3.28 (t, 1
H, J = 9.6 Hz, H-4), 3.14 (dd, 1 H, J = 9.6, 3.6 Hz, H-2).
Synthesis 2002, No. 10, 1407–1411 ISSN 0039-7881 © Thieme Stuttgart · New York

1410
M. T. Barros, F. Siñeriz
PAPER
13C NMR (CDCl3): = 58.95, 59.25, 59.39, 59.83, 60.10, 61.05,
61.32, (7 CH3O), 62.01 (C-6 ), 70.93 (C-5), 71.67 (C-6), 74.77 (C-
1 ), 79.56 (C-4), 81.64 (C-5 ), 81.98 (C-2), 82.13 (C-3), 83.63 (C-
4 ), 85.78 (C-3 ), 91.13 (C-1), 104.16 (C-2 ).
6 -O-(Methacryloyl)-2,3,4,6,1 ,3 ,4 -hepta-O-benzoylsucrose (9)
The reaction of 6 (1.08 g, 1.0 mmol) with methacrylic anhydride
(0.18 mL, 1.2 mmol) was carried out according to the general pro-
cedure during 1.5 h. Chromatographic purification (silica gel,
EtOAc–hexane, 1:2) afforded 0.92 g (80%) of 9; [ ]D +37.8 (c = 1.1,
CHCl3).
2,3,4,6,1 ,3 ,4 -Hepta-O-(tri-O-methylgalloyl)sucrose (7)
Compound 4 (1.00 g, 0.5 mmol) was refluxed in a 0.1% (w/w) so-
lution of Br2 in MeOH (82 mL) for 6 h. Then, the mixture was
cooled and the excess of Br2 was destroyed by a solution of aq 5%
Na2S2O3 (20 mL). The aqueous layer was extracted with CH2Cl2
(3 30 mL) and the combined organic layers were dried (Na2SO4),
concentrated, and the residue was purified on silica gel (EtOAc–
hexane, 2:1) to give 7 (0.64 g, 73%); [ ]D +14.1 (c = 0.8, CHCl3).
Unchanged starting material 4 (0.22 g, 22%) was also recovered.
1H NMR (CDCl3): = 8.20–7.14 (m, 35 H, Ar), 6.21 (t, 1 H,
J = 10.0 Hz, H-3), 6.15 (d, 1 H, J = 3.4 Hz, H-1), 6.14 (s, 1 H, H-
a), 5.97 (d, 1 H, J = 5.5 Hz, H-3 ), 5.93 (t, 1 H, J = 5.5 Hz, H-4 ),
5.78 (t, 1 H, J = 9.9 Hz, H-4), 5.50 (s, 1 H, H- b), 5.44 (dd, 1 H,
J = 10.4, 3.5 Hz, H-2), 4.71 (d, 1 H, J = 11.9 Hz, H-1 a), 4.70 (m,
1 H, H-5 or H-5 ), 4.60 (d, 1 H, H-1 b), 4.52 (s, 2 H, 2 H-6), 4.47–
4.45 (m, 2 H, H-5 or H-5 and H-6 a), 4.35 (dd, 1 H, J = 12.5, 3.0
Hz, H-6 b), 1.89 (s, 3 H, CH3CH=CH2).
1H NMR (CDCl3): = 7.39–7.06 (7 s, 14 H, Ar), 6.27 (d, 1 H,
J = 3.2 Hz, H-1), 6.01 (t, 1 H, J = 10.0 Hz, H-3), 5.96 (m, 2 H, H-
3 and H-4 ), 5.74 (t, 1 H, J = 10.0 Hz, H-4), 5.16 (dd, 1 H, J = 10.2,
3.6 Hz, H-2), 4.66 (d, 1 H, J = 11.6 Hz, H-1 a), 4.58 (d, 1 H,
J = 11.6 Hz, H-1 b), 4.56 (m, 1 H, H-5), 4.20–4.01 (m, 5 H, 2 H-6,
H-5 and 2 H-6 ), 3.93–3.76 (11 s, 63 H, 21 CH3O), 1.26 (br s, 1 H,
OH).
13C NMR (CDCl3): = 56.67 (CH3OAr), 61.35 (CH3OAr), 62.13,
63.28, 65.31 (C-6, C-1 and C-6 ), 69.53, 69.81, 71.81, 72.50 (C-2,
C-3, C-4 and C-5), 75.09, 78.29 (C-3 and C-4 ), 82.26 (C-5 ), 94.17
(C-1), 103.71 (C-2 ), 107.54–153.38 (Ar), 165.60, 165.79, 165.90,
166.00, 166.40, 166.51, 167.08 (7 CO).
13C NMR (CDCl3): = 18.04 (CH3CH=CH2), 62.23, 63.60, 64.92
(C-6, C-1 and C-6 ), 68.95, 69.12, 70.03, 71.25 (C-2, C-3, C-4 and
C-5), 76.05, 77.53 (C-3 and C-4 ), 78.96 (C-5 ), 90.77 (C-1),
104.60 (C-2 ), 126.40, 128.29–135.76 (Ar and CH=CH2), 165.20,
165.46, 165.50, 165.66, 165.91, 166.14, 166.92 (8 CO).
Anal. Calcd for C65H54O19 (1139.11): C, 68.54; H, 4.78. Found: C,
68.68; H, 4.77.
6 -O-(Methacryloyl)-2,3,4,6,1 ,3 ,4 -hepta-O-(tri-O-methylgal-
loyl)sucrose (10)
The reaction of 7 (0.17 g, 0.1 mmol) with methacrylic anhydride
(17.8 L, 0.1 mmol) was carried out according to the general proce-
dure during 30 min. Chromatographic purification (silica gel,
EtOAc–hexane, 2:1) afforded 0.14 g (80%) of 10; [ ]D +17.7 (c =
0.7, CHCl3).
1H NMR (CDCl3): = 7.35–7.02 (7 s, 14 H, Ar), 6.22 (d, 1 H,
J = 3.6 Hz, H-1), 6.11 (s, 1 H, H- a), 5.96 (t, 1 H, J = 10.0 Hz, H-
3), 5.92 (t, 1 H, J = 4.8 Hz, H-3 ), 5.81 (t, 1 H, J = 10.0 Hz, H-4 ),
5.70 (t, 1 H, H-4), 5.53 (s, 1 H, H- b), 5.20 (dd, 1 H, J = 11.2, 3.6
Hz, H-2), 4.82–4.51 (m, 7 H, H-5, H-6a, 2 H-1 , H-5 , 2 H-6 ), 4.20
(dd, 1 H, J = 13.8, 3.4 Hz, H-6b), 3.92–3.69 (12 s, 63 H, 21 CH3O),
1.87 (s, 3 H, CH3CH=CH2).
Synthesis of Monomers; General Procedure
To a 0.1 M solution of the 6 -OH free sugars 5–7 in anhyd CH2Cl2
was added Et3N (2.5 equiv) and a catalytic amount of 4-DMAP. The
mixture was cooled at 0 °C, and then a 0.5 M solution of methacryl-
ic anhydride or crotonic anhydride (cis/trans mixture) (1.2 equiv) in
anhyd CH2Cl2 was added. The reaction mixture was allowed to
warm until r.t. When no more starting material remained, the mix-
ture was diluted with more CH2Cl2 (5 15 mL per mmol of starting
material) and washed with aq 1.0 M HCl (15 mL per mmol of start-
ing material), H2O (15 mL per mmol starting material), sat. aq
NaHCO3 (15 mL per mmol starting material) and brine (15 mL per
mmol starting material). The organic layer was dried (Na2SO4) and
the solvent was evaporated. Purification of the crude by flash chro-
matography led to the expected products 8–13.
13C NMR (CDCl3):
= 18.86 (CH3CH=CH2), 56.57–56.96
(CH3OAr), 61.53 (CH3OAr), 63.17, 64.27, 65.66 (C-6, C-1 and C-
6 ), 69.88, 70.04, 71.18, 72.70 (C-2, C-3, C-4 and C-5), 77.16, 78.01
(C-3 and C-4 ), 80.41 (C-5 ), 91.54 (C-1), 105.97 (C-2 ), 107.56–
153.76 (Ar and CH=CH2), 165.52, 165.60, 165.87, 165.92, 166.31,
167.43 (8 CO).
6 -O-(Methacryloyl)-2,3,4,6,1 ,3 ,4 -hepta-O-methylsucrose (8)
The reaction of 5 (0.79 g, 1.8 mmol) with of methacrylic anhydride
(0.32 mL, 2.2 mmol) was carried out according to the general pro-
cedure during 24 h. Purification by column chromatography on sil-
ica gel (EtOAc–hexane, 3:1) afforded 0.69 g (76%) of 8; [ ]D +49.9
(c = 1.0, CHCl3).
1H NMR (CDCl3): = 6.14 (s, 1 H, H- a), 5.57 (t, 1 H, J = 1.6 Hz,
H- b), 5.50 (d, 1 H, J = 3.4 Hz, H-1), 4.39 (m, 2 H, 2 H-6 ), 4.05
(m, 1 H, H-3 ), 4.03 (t, 1 H, J = 7.5 Hz, H-5 ), 3.93 (m, 1 H, H-5),
3.89 (t, 1 H, J = 7.5 Hz, H-4 ), 3.62 (m, 1 H, H-1 a), 3.61, 3.54, 3.48,
3.46, 3.44, 3.42, 3.40 (7 s, 21 H, 7 CH3O), 3.59 (m, 2 H, 2 H-6),
3.57 (m, 1 H, H-3), 3.53 (m, 1 H, H-1 b), 3.19 (dd, 1 H, J = 10.0,
9.6 Hz, H-4), 3.13 (dd, 1 H, J = 9.7, 3.6 Hz, H-2), 1.94 (s, 3 H,
CH3CH=CH).
Anal. Calcd for C86H96O40 (1769.70): C, 58.37; H, 5.47. Found: C,
58.62; H, 5.89.
6 -O-(Crotonyl)-2,3,4,6,1 ,3 ,4 -hepta-O-methylsucrose (11)
The reaction of 5 (0.50 g, 1.1 mmol) with crotonic anhydride (0.20
mL, 1.4 mmol) was carried out according to the general procedure
during 24 h. Chromatographic purification (silica gel, EtOAc–hex-
ane, 3:1) afforded 0.38 g (65%) of 11; [ ]D +59.7 (c = 1.0, CHCl3).
1H NMR (CDCl3): = 6.93 (dq, 1 H, J = 15.2, 6.8 Hz, H- ), 5.80
(d, 1 H, J = 15.4, H- ), 5.44 (d, 1 H, J = 3.6 Hz, H-1), 4.29 (m, 2 H,
2 H-6 ), 3.96 (m, 1 H, H-3 ), 3.93 (m, 1 H, H-5 ), 3.85 (m, 1 H, H-
5), 3.80 (t, 1 H, J = 7.6 Hz, H-4 ), 3.54, 3.46, 3.41, 3.39, 3.36, 3.34,
3.32 (7 s, 21 H, 7 CH3O), 3.52 (m, 1 H, H-1 a), 3.51 (m, 2 H, 2 H-
6), 3.40 (m, 1 H, H-3), 3.34 (m, 1 H, H-1 b), 3.12 (t, 1 H, J = 9.6 Hz,
H-4), 3.05 (dd, 1 H, J = 9.4, 3.7 Hz, H-2). 1.81 (d, 3 H, 6.4 Hz,
CH3CH=CH).
13C NMR (CDCl3): = 18.00 (CH3CH=CH2), 58.16, 58.26, 58.32,
59.91, 59.18, 60.07, 60.41 (7 CH3O), 65.70 (C-6 ), 70.30 (C-5),
70.96 (C-6), 73.53 (C-1 ), 78.06 (C-5 ), 79.25 (C-4), 81.45 (C-2),
82.92 (C-3), 83.99 (C-4 ), 84.92 (C-3 ), 89.27 (C-1), 104.21 (C-2 ),
125.76 (CH3CH=CH2), 136.05 (CH3CH=CH2), 167.13 (CO).
13C NMR (CDCl3): = 17.77 (CH3CH=CHCO), 58.17, 58.33,
58.94, 59.19, 60.09, 60.45 (7 CH3O), 65.31 (C-6 ), 70.27 (C-5),
70.95 (C-6), 73.55 (C-1 ), 78.13 (C-5 ), 79.23 (C-4), 81.46 (C-2),
82.90 (C-3), 83.70 (C-4 ), 84.91 (C-3 ), 89.22 (C-1), 104.04 (C-2 ),
122.25 (CH3CH=CH), 144.89 (CH3CH=CH), 165.97 (CO).
Anal. Calcd for C23H40O12 (508.56): C, 54.32; H, 7.93. Found: C,
54.37; H, 8.02.
Synthesis 2002, No. 10, 1407–1411 ISSN 0039-7881 © Thieme Stuttgart · New York

PAPER
Protected 6 -O-Acryloyl Sucroses
1411
Anal. Calcd for C23H40O12 (508.56): C, 54.32; H, 7.93. Found: C,
54.22; H, 8.02.
Acknowledgements
The authors wish to express their appreciation to Professor António
Portugal, Universidade de Coimbra, Portugal, for obtaining SEC
analyses. This work has been supported by NATO SFS (PO-SU-
GARS) and Fundação para a Ciência e a Tecnologia (grant PRAXIS
XXI/BD/17007/98 for F.S.).
6 -O-(Crotonyl)-2,3,4,6,1 ,3 ,4 -hepta-O-benzoylsucrose (12)
The reaction of 6 (0.50 g, 0.5 mmol) with crotonic anhydride (83.5
L, 0.6 mmol) was carried out according to the general procedure
during 1.5 h. Chromatographic purification (silica gel, EtOAc–hex-
ane, 1:2) afforded 0.43 g (80%) of 12; [ ]D +33.0 (c = 1.0, CHCl3).
1H NMR (CDCl3): = 8.21–7.12 (m, 35 H, Ar), 6.95 (dq, 1 H,
J = 15.6, 6.8 Hz, H- ), 6.24 (t, 1 H, J = 5.0 Hz, H-3), 6.15 (d, 1 H,
J = 3.2 Hz, H-1), 5.97 (d, 1 H, J = 5.6 Hz, H-3 ), 5.91 (t, 1 H,
J = 5.6 Hz, H-4 ), 5.83 (d, 1 H, J = 15.6 Hz, H- ), 5.79 (t, 1 H,
J = 9.4 Hz, H-4), 5.45 (dd, 1 H, J = 10.6, 3.4 Hz, H-2), 4.73 (m, 2
H, H-1 a and H-5or H-5 ), 4.61 (d, 1 H, J = 12.0 Hz, H-1 b), 4.50
(m, 4 H, H-6a, H-5 or H-5 and 2 H-6 ), 4.35 (dd, 1 H, J = 12.4, 3.2
Hz, H-6b), 1.72 (d, 3 H, J = 6.8 Hz, CH3CH=CHCO).
13C NMR (CDCl3): = 17.82 (CH3CH=CHCO), 62.28, 63.16, 64.78
(C-6, C-1 and C-6 ), 68.94, 69.12, 70.03, 71.25 (C-2, C-3, C-4 and
C-5), 76.06, 77.38 (C-3 and C-4 ), 79.04 (C-5 ), 90.80 (C-1),
104.58 (C-2 ), 121.84, 128.21–133.55 (Ar and CH=CH), 164.99,
165.25, 165.42, 165.68, 165.76, 166.94 (8 CO).
References
(1) Wulff, G.; Zhu, L.; Schmidt, H. Macromolecules 1997, 30,
4533.
(2) Dordick, J. S.; Linhardt, R. J.; Rethwisch, D. Chemtech
1994, 33.
(3) Black, W. A. P.; Colquhoun, J. A.; Dewar, E. T. Makromol.
Chem. 1969, 122, 244.
(4) Klein, J. Makromol. Chem. 1987, 188, 1217.
(5) Klein, J. Makromol. Chem. 1988, 189, 805.
(6) Sachinvala, N. D.; Niemczura, W. P.; Litt, M. H. Carbohydr.
Res. 1991, 218, 237.
(7) Carneiro, M. J.; Fernandes, A.; Figueiredo, C. M.; Fortes, A.
G.; Freitas, A. M. Carbohydr. Polym. 2001, 45, 135.
(8) Jhurry, D.; Deffieux, A.; Fontanille, M.; Betremieux, I.;
Mentech, J.; Descotes, G. Makromol. Chem. 1992, 193,
2297.
Anal. Calcd for C65H54O19 (1139.11): C, 68.54; H, 4.78. Found: C,
68.34; H, 4.94.
6 -O-(Crotonyl)-2,3,4,6,1 ,3 ,4 -hepta-O-(tri-O-methylgalloyl)-
sucrose (13)
(9) Potier, P.; Bouchou, A.; Descotes, G.; Queneau, Y.
Tetrahedron Lett. 2000, 41, 3597.
The reaction of 7 (0.17 g, 0.1 mmol) with crotonic anhydride (0.017
mL, 0.1 mmol) was carried out according to the general procedure
during 30 min. Chromatographic purification (silica gel, EtOAc–
hexane, 2:1) afforded 0.14 g (81%) of 13; [ ]D +18.1 (c = 0.3,
CHCl3).
1H NMR (CDCl3): = 7.41–7.01 (7 s, 14 H, Ar), 6.91 (dq, 1 H,
J = 15.6, 6.8 Hz, H- ), 6.23 (d, 1 H, J = 3.6 Hz, H-1), 5.98 (t, 1 H,
J = 10.0 Hz, H-3), 5.94 (d, 1 H, J = 4.8 Hz, H-3 ), 5.80–5.69 (m, 3
H, H-4, H-4 and H- ), 5.19 (dd, 1 H, J = 10.4, 3.6 Hz, H-2), 4.78–
4.52 (m, 7 H, H-5, H-6a, 2 H-1 , H-5 and 2 H-6 ), 4.22 (dd, 1 H,
J = 13.8, 3.4 Hz, H-6b), 3.93–3.68 (10 s, 63 H, 21 CH3O), 1.77 (d,
3 H, J = 13.6, CH3CH=CHCO).
(10) Ferreira, L.; Vidal, M. M.; Geraldes, C. F. G. C.; Gil, M. H.
Carbohydr. Polym. 2000, 41, 15.
(11) Chen, J.; Park, K. Carbohydr. Polym. 2000, 41, 259.
(12) Fanton, E.; Fayet, C.; Gelas, J.; Jhurry, D.; Deffieux, A.;
Fontanille, M. Carbohydr. Res. 1992, 226, 337.
(13) Fanton, E.; Fayet, C.; Gelas, J.; Deffieux, A.; Fontanille, M.;
Jhurry, D. Carbohydr. Res. 1993, 240, 143.
(14) Patil, D. R.; Dordick, J. S.; Rethwisch, D. Macromolecules
1991, 24, 3462.
(15) Buchanan, J. G.; Cummerson, D. A.; Turner, D. M.
Carbohydr. Res. 1972, 21, 283.
(16) Franke, F.; Guthrie, R. D. G. Aust. J. Chem. 1977, 30, 639.
(17) Capek, K.; Vodrázková-Medonosová, M.; Moravcová, J.;
Sedmera, P. Collect. Czech. Chem. Commun. 1986, 51,
1476.
13C NMR (CDCl3):
= 18.64 (CH3CH=CHCO), 56.50–56.95
(CH3OAr), 61.51 (CH3OAr), 63.23, 64.02, 65.34 (C-6, C-1 and C-
6 ), 69.85, 70.02, 71.18, 72.75 (C-2, C-3, C-4 and C-5), 77.10, 78.01
(C-3 and C-4 ), 80.71 (C-5 ), 91.65 (C-1),106.14 (C-2 ), 107.54–
153.75 (Ar), 165.43, 165.63, 165.79, 165.87, 165.96, 166.27,
166.30, 166.43 (8 CO).
(18) Capek, K.; Vydra, T.; Sedmera, P. Collect. Czech. Chem.
Commun. 1988, 53, 1317.
(19) Chang, K.-Y.; Wu, S.-H.; Wang, K.-T. Carbohydr. Res.
1991, 222, 121.
(20) Palmer, D. C.; Terradas, F. Tetrahedron Lett. 1994, 35,
1673.
(21) Barros, M. T.; Maycock, C. D.; Siñeriz, F.; Thomassigny, C.
Tetrahedron 2000, 56, 6511.
(22) Karl, H.; Lee, C. K.; Khan, R. Carbohydr. Res. 1982, 101,
31.
(23) (a) Greene, T. W.; Wuts, P. G. M. Protective Groups in
Organic Synthesis, 2nd ed.; Wiley: New York, 1991.
(b) Motawia, M. S.; Larsen, K. M.; Olsen, C. E.; Moller, B.
L. Synthesis 2000, 1547.
(24) Sano, T.; Ohashi, K.; Oriyama, T. Synthesis 1999, 1141.
(25) Barros, M. T.; Maycock, C. D.; Thomassigny, C. Synlett
2001, 1146.
(26) Perrin, D. D.; Armarego, W. L. F.; Perrin, D. R. Purification
of Laboratory Chemicals, 2nd Ed.; Pergamon: New York,
1980.
Anal. Calcd for C86H96O40 (1769.70): C, 58.37; H, 5.47. Found: C,
58.03; H, 5.71.
Copolymerization of 9
Copolymerizations of compound 9 with styrene or methyl meth-
acrylate were carried out in anhyd toluene (0.02 M) in the presence
of AIBN as radical initiator (1 mol% by weight with respect to the
monomer mixtures). All solutions were flushed with argon in order
to remove oxygen. The reactions were kept at 70 °C for 24 h. Then,
the solutions were cooled to r.t. and the product precipitated by
dropwise addition into excess of cold (0 °C) EtOH. The white solids
were filtered and washed several times with EtOH. The polymers
were purified by repeated dissolution in toluene and reprecipitation
in cold EtOH and subsequently dried in vacuum at 60 °C. Polymer-
ization yields and compositions of the copolymers are reported in
the Table.
Synthesis 2002, No. 10, 1407–1411 ISSN 0039-7881 © Thieme Stuttgart · New York