Dendronized polyacrylates with glucose units in the periphery

Article abstract of DOI:10.1039/a808373h

The synthesis of dendritic building blocks (dendrons) of the first (G-1) and second generation (G-2) with peripheral acetyl-protected glucose moieties is reported. The dendrons can be selectively deprotected at the focal point and the resulting carboxylic

Full text of DOI:10.1039/a808373h

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Dendronized polyacrylates with glucose units in the periphery
Andrea Zistler, Sabine Koch and A. Dieter Schlüter*
Institut für Organische Chemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany.
Fax.: Int. ϩ49 30 838 3357. E-mail: adschlue@chemie.fu-berlin.de
Received (in Cambridge) 29th October 1998, Accepted 10th December 1998
The synthesis of dendritic building blocks (dendrons) of the first (G-1) and second generation (G-2) with peripheral
acetyl-protected glucose moieties is reported. The dendrons can be selectively deprotected at the focal point and
the resulting carboxylic acids then attached to an acrylic acid derivative to furnish dendronized G-1 and G-2
macromonomers. Their radically initiated polymerization leads to dendronized polyacrylates with two and four
surface glucose units per repeat unit.
YHN
NHY
Introduction
In recent years surface-functionalized dendrimers1 have become
particularly interesting because of their and the attached res-
HO
OH
O
O
idues’ unique properties. The dense packing of the residues on
the dendrimers’ surface has a cooperative effect upon these
properties.2–4 The multivalent effect of clustered saccharides5
is well known for carbohydrate–protein interactions,6 and a
variety of carbohydrate-functionalized dendrimers have been
prepared to obtain model compounds for the study of carbo-
hydrate–protein interactions and new neoglycoconjugates.7–10
The goal of a long-term project in our group is to make
organic molecular objects available which have a defined and
predetermined shape and nanometer scale.11 Dendronized poly-
styrenes and poly(para-phenylene)s were shown to have a
cylindrical shape in the condensed phase as well as in solution.12
Recently we described the synthesis of various dendronized
polystyrenes with hydroxy and amino groups on the periph-
ery.13,14 This was the first step towards surface-functionalized
cylinders carried out to engineer the properties of these unusual
macromolecules. Here we present a next step toward this goal,
which is the synthesis of new glucose-functionalized G-1 and
G-2 dendronized acrylic monomers 14 and 16 and the results
of their radically initiated polymerization. Glucose serves as a
model for biologically more relevant carbohydrate derivatives
which will be utilized at a later stage.
b
CO2X
CO2CH2CH CH2
4 Y = Boc
1 X = H
a
c
2 X = CH C
5 Y = H•HCl
NHBoc
H
CH2
2
Cl
3
OAc
AcO
OAc
OAc
O
OAc
OAc
6
AcO
OAc
S
d
+
CO2H
O
OAc
CO2H
HS
8
Results and discussion
7
Recently we reported the convergent synthesis of a series of
dendritic building blocks, which carry amino or hydroxy groups
on the periphery and a carboxylic ester at the focal point.15
Additionally, higher generation dendrons were synthesized
according to a repetitive strategy from orthogonally protected
G-1 building blocks. Amide formation proved a very successful
growth step in many of these cases. It was therefore also applied
in the present work to connect (a) G-1 dendrons to larger ones,
(b) the glucose moieties to the amino-terminated dendrons, and
(c) the sugar-coated dendrons to the polymerizable group in
order to obtain the desired macromonomers 14 and 16. The
acetyl protective group on glucose was selected for cost reasons
and because it can be easily and cleanly removed. The allylic
carboxylates at the focal points of target molecules 9 and 11
have the advantage that they can be selectively cleaved in the
presence of the peripheral acetates by a variety of transition-
metal-catalyzed procedures.
Scheme 1 Synthesis of G-1 aminodendron 5 and glucose unit 8.
Reagents and conditions (yields): (a) prop-2-enol, H2SO4, reflux, 8 h
(90%); (b) 1-(butoxycarbonylamino)-3-chloropropane 3, K2CO3, 18-C-
6, tetrabutylammonium iodide (TBAI), diethyl ketone, reflux, 18 h
(81%); (c) THF, HCl, RT, 3 h (97%); (d) BF3ؒEt2O, CH2Cl2, RT, 2 h
(86%).
by a Williamson-type etherification of ester 2 with Boc-
protected 3-chloropropylamine 3. The peripherally deprotected
G-1 dendron 5 was prepared by treatment of protected amine 4
with dil. hydrochloric acid in THF and isolated as the dihydro-
chloride in 97% yield. Compound 5 serves two purposes: the
attachment of the carbohydrate moieties to give compound 9
and as an inner building block for the construction of the G-2
dendron 11 (Scheme 2). Acetyl-protected glucose was modified
with a spacer according to an effective procedure16 described by
Stoddart and co-workers for galactose and lactose.10c The thio-
glycoside 8 was obtained as analytically pure material in 86%
yield from penta-O-acetyl glucose 6 and 3-mercaptopropionic
acid 7. In the next step amino dendron 5 was derivatized by
The synthesis starts with esterification of cheap γ-resorcylic
acid 1 to yield the allylic ester 2 (Scheme 1). The Boc-protected
G-1 dendron 4 was obtained on the 20 gram scale in 81% yield
J. Chem. Soc., Perkin Trans. 1, 1999, 501–508
501

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+
5
8
a
OAc
OAc
OAc
OAc
AcO
AcO
AcO
OAc
O
O
S
S
O
O
HN
NH
O
O
CO2X
9 X = CH2CH CH2
10 X = H
b
OAc
AcO
AcO
OAc
OAc
AcO
O
O
AcO
S
S
OAc
O
O
OAc
AcO
NH
HN
AcO
OAc
O
O
AcO
OAc
O
O
O
O
S
S
AcO
OAc
N
N
H
H
O
O
O
O
HN
NH
O
O
c
+
5
10
CO2X
11 X = CH2CH CH2
12 X = H
d
Scheme 2 Synthesis of glucose-modified dendrons 9 and 11. Reagents and conditions (yields): (a) (i) 8, HOBT, CH2Cl2, RT, 10 min (ii) 5, diisopropyl-
ethylamine (DIPEA), 30 min (iii) EDC, 18 h (91%); (b) PdCl2(PPh3)2, TBTH, 0 ЊC, 2 h (94%); (c) (i) 10, HOBT, CH2Cl2, RT, 10 min (ii) 5, DBU, 30
min (iii) EDC, 18 h (68%); (d) PdCl2(PPh3)2, TBTH, 0 ЊC, 2 h (60%).
attachment of two units of acid 8 (Scheme 2). Amide coupling
was done by the convenient 1-[3-(dimethylamino)propyl]-3-
ethylcarbodiimide (EDC)–HOBT method17 and yielded the
sugar G-1 dendron 9 on the 15 g scale in 91% yield. Selective
deprotection of the allyl ester at the focal point did not affect
the peripheral acetoxy groups and was best achieved with 2%
PdCl2(PPh3)2 and tributyltin hydride (TBTH). The reaction was
performed on the 15 gram scale and gave the carboxylic acid 10
in excellent yields of 92–94%. The obtained product, however,
contained some small quantities of tin impurities, which could
not be entirely removed. To obtain analytically pure acid 10
the deprotection step was performed with 10% Pd(PPh3)4 and
morpholine. This reaction was only carried out on the gram
scale and gave the carboxylic acid 10 in 30% yield. Because of
this unsatisfactory yield and the fact that the tin impurities did
not interfere with the subsequent steps, the tin hydride method
was preferred over the latter, and was the method we normally
used.
Combination of two equivalents of acid 10 with amino den-
dron 5 gave the G-2 dendron 11. Amide coupling was per-
formed analogously to the preparation of compound 9 and
gave the sugar-functionalized second-generation dendron 11 in
68% yield. Cleavage of the allyl ester again was achieved with
PdCl2(PPh3)2–TBTH and yielded the G-2 carboxylic acid 12 in
a clean and fast reaction (60%, losses during chromatography).
The obtained G-1 (10) and G-2 (12) carboxylic acids were
used in the construction of dendronized macromonomers.
Acrylate 13e, easily obtained in four steps from acid 13a, was
502
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OAc
OAc
OAc
OAc
AcO
AcO
AcO
OAc
O
O
S
S
O
O
HN
NH
X
e
O
O
10
+
Y
13
O
NH
a X = NH2, Y = CO2H
b X = NHBoc, Y = CO2H
c X = NHBoc, Y = CH2OH
a
b
c
H
H
CH2
CH2
d X = NHBoc, Y = CH2O(CO)C
d
e X =NH2•HCl, Y = CH2O(CO)C
O
O
14
OAc
OAc
OAc
OAc
AcO
AcO
AcO
OAc
O
O
S
S
O
O
HN
NH
O
O
O
NH
f
O
O
n
15
Scheme 3 Synthesis of G-1 macromonomer 14 and its polymerization. Reagents and conditions (yields): (a) 13a, di-tert-butyl dicarbonate, KOH,
THF, RT, 1 h (94%); (b) 13b, LAH, THF, 40 ЊC, 14 h (63%); (c) 13c, NEt3, DMAP, acryloyl chloride, THF, RT, 16 h (76%); (d) 13d, HCl, THF, RT,
36 h (83%); (e) (i) 10, HOBT, CH2Cl2, RT, 10 min (ii) 13e, DIPEA, 30 min (iii) EDC, 24 h (88%); (f) AIBN, benzene, 55 ЊC, 16 h (92%).
chosen as the polymerizable unit (Schemes 3 and 4), as acrylates
have been successfully used by various groups in the prepar-
ation of vinyl sugar polymers and copolymers.18–20 The carbo-
hydrate-functionalized dendrons were attached to compound
13e again by the EDC–HOBT procedure. Macromonomers 14
(G-1) and 16 (G-2) were obtained as very viscous oils in yields
of 88% and 76%, respectively. They could be lyophilized from
1,4-dioxane. Polymerizations were carried out in highly concen-
trated solutions using AIBN as starter at 55 ЊC for substrate 14
and tert-butyl perbenzoate (tBPB) at 90 ЊC for substrate 16. The
very small amounts of solvent required were added with a pre-
cision micropipette. The polymers were obtained in yields of
92% (15) and 46% (17).21 The 1H and 13C NMR spectra of both
monomers and polymers are rather complex. Nevertheless all
signals could be assigned. The relative molecular masses of
polymers 15 and 17 were determined by gel-permeation chrom-
atography (GPC) versus a polystyrene standard as Mn = 70 860
(Pn = 55), Mw = 157 100 (Pw = 123) for 15 and Mn = 11 700
(Pn = 4.5), Mw = 12 050 (Pw = 5) for 17. Whereas the values for
polymer 15 were more or less as expected,22 those for polymer
17 are unusual for two reasons. The degrees of polymerization
are rather low and the relative molecular mass distribution (Mw/
Mn = 1.03) is extremely narrow for a free-radical process. Obvi-
ously the polymerization self-terminates as soon as a certain
J. Chem. Soc., Perkin Trans. 1, 1999, 501–508
503

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OAc
AcO
AcO
OAc
OAc
AcO
O
O
AcO
S
S
OAc
O
O
OAc
AcO
NH
HN
AcO
OAc
O
O
AcO
OAc
O
O
O
O
S
S
AcO
OAc
N
N
H
H
O
O
O
O
HN
NH
O
O
b
a
O
+
12
13
17 (Polymer of 16)
NH
O
O
16
Scheme 4 Synthesis of G-2 macromonomer 16 and its polymerization. Reagents and conditions (yields): (a) (i) 12, HOBT, CH2Cl2, RT, 10 min (ii)
13e, DBU, 30 min (iii) EDC, 24 h (76%); (b) tBPB, toluene, 90 ЊC, 16 h (46%).
relative molecular mass is reached. This may indicate that the
growing chain folds inward due to the steric demand of the
dendrons, thus rendering the active chain inaccessible for
further growth. Another explanation involves the assumption
of a size-limited pre-aggregation of monomers to a ‘molecular
reactor’ consisting of a defined number of constituents which
then polymerizes.23 Further work is required to differentiate
these possibilities. It should also be noted at this point that
GPC tends to underestimate the actual relative molecular
masses of dendronized polymers by factors which easily can
reach 2–3.24
with saturated aq. sodium hydrogen carbonate (4 × 150 ml) and
brine, dried with magnesium sulfate, and evaporated in vacuo.
Chromatographic separation [silica gel; hexane–ethyl acetate
(3:1 v/v)] afforded title ester 2 (106 g, 90%) as a viscous oil,
1H-NMR δ(CDCl3–CD3OD) 3.96 (br s, 2H, OH), 4.66 (d, 2H,
CO CH ), 5.20 (dd, 2H, CH᎐CH ), 5.89 (ddd, 1H, CH᎐CH ),
᎐
᎐
2
2
2
2
6.40 (t, 1H, ArH) and 6.89 (d, 2H, ArH); 13C-NMR δ(CDCl3–
CD3OD) 65.7 (CO2CH2), 107.7 (ArC-H), 108.4 (ArC-H), 118.9
(CH᎐CH ), 131.5 (CH᎐CH ), 131.6 (ArC-CO R), 157.5 (ArC-
᎐
᎐
2
2
2
OH) and 166.8 (CO2R); MS (80 eV) m/z (%) 194 (54) [M]ϩ, 138
(27) [M Ϫ C3H4O]ϩ and 137 (100) [M Ϫ C3H5O]ϩ; HRMS
(Found: 194.055 23 [M]ϩ. C10H10O4 requires M, 194.057 91).
Experimental
General procedures
Allyl 3,5-bis-[3-(tert-butoxycarbonylamino)propoxy]benzoate 4
A solution of diol 2 (7.77 g, 40 mmol), 3-(tert-butyloxycarbonyl-
amino)propyl chloride 3 (23.5 g, 121 mmol), potassium carb-
onate (16.6 g, 0.2 mol), 18-crown-6 (3.16 g), TBAI (4.94 g) and
sodium iodide (1.32 g) in 500 ml of freshly distilled diethyl
ketone was refluxed for 18 h. The solution was filtered, washed
successively with saturated aq. sodium hydrogen carbonate and
brine, dried with magnesium sulfate, and evaporated in vacuo.
Chromatographic separation [silica gel; hexane–ethyl acetate
(2:1 v/v)] gave title compound 4 (16.4 g, 81%) as a solid,
1H-NMR δ(CDCl3) 1.35 (s, 18H, CH3), 1.87 (quin, 4H, CH2-
CH2CH2), 3.20 (q, 4H, NHCH2), 3.95 (t, 4H, ArOCH2), 4.71 (d,
All reagents were purchased from Fluka or Aldrich and used
without further purification. All solvents were dried under
standard conditions. All reactions were carried out under nitro-
gen. Analytical equipment: (a) NMR spectra: Bruker AMX
500 spectrometer (500 MHz) and Bruker AM 250 spectrometer
(250 MHz); (b) mass spectra: Varian MAT 112S, Varian MAT
711; (c) elemental analyses: EA 240 Perkin Elmer; (d) GPC:
Waters Ultra Styragel linear column [RI (refractive index) and
UV (230 nm) detection; polystyrene standard; THF eluent].
Allyl 3,5-dihydroxybenzoate 2
2H, CO CH ), 4.90 (br s, 2H, NH), 5.26 (dd, 2H, CH᎐CH ),
᎐
2
2
2
A solution of 3,5-dihydroxybenzoic acid 1 (93.5 g, 607 mmol)
and 9.0 ml of conc. H2SO4 in 250 ml of prop-2-enol was
refluxed for 8 h. The solution was neutralized with saturated aq.
sodium hydrogen carbonate and evaporated under vacuum.
The residue was taken up in ethyl acetate, washed successively
5.93 (ddd, 1H, CH᎐CH ), 6.55 (t, 1H, ArH) and 7.13 (d, 2H,
᎐
2
ArH); 13C-NMR δ(CDCl3) 28.3 (CH2CH2CH2), 29.4 (CH3),
37.7 (NHCH2), 65.6 (CO2CH2), 65.9 (OCH2), 79.0 [C(CH3)3],
106.4 (ArC-H), 107.8 (ArC-H), 118.2 (CH᎐CH ), 131.8 (ArC-
᎐
2
CO R), 132.0 (CH᎐CH ), 155.9 (NHCO ), 159.7 (ArC-O) and
᎐
2
2
2
504
J. Chem. Soc., Perkin Trans. 1, 1999, 501–508

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165.8 (CO2R); MS (80 eV) m/z (%) 508 (3.8) [M]ϩ; [C26H40N2O8
(508.6): Found: C, 61.0; H, 7.7; N, 5.35. Calc. C, 61.40; H, 7.93;
N, 5.51%].
(ArC-O), 165.8 (ArCO2R), 169.3, 170.0 and 170.6 (COCH3)
and 171.1 (CONH); EI-MS (280 ЊC) m/z (%) 1144 (0.33) [M]ϩ,
813 (22) [M Ϫ Glu (C14H19O9)]ϩ and 331 (22) [Glu (C14H19-
O9)]ϩ; HRMS (Found: 813.253 41 [M Ϫ Glu (C14H19O9)]ϩ.
C36H49N2O15S2 requires m/z, 813.257 44).
Allyl 3,5-bis-(3-aminopropoxy)benzoate dihydrochloride 5
A solution of compound 4 (2.6 g, 5.11 mmol) and hydrochloric
acid (25%; 21 ml, 147 mmol) in 30 ml of dry THF was stirred
for 3 h and then poured into 500 ml of acetone. After being
cooled to 4 ЊC for 24 h the precipitate was filtered off by
suction and dried in vacuo to give title compound 5 (1.89 g,
3,5-Bis-{3-[3-(2,3,4,6-tetra-O-acetyl-â-D-glucopyranosylthio)-
propionamido]propoxy}benzoic acid 10
To a solution of G-1 allylic ester 9 (14.6 g, 12.7 mmol) and
PdCl2(PPh3)2 (210 mg, 0.30 mmol) in 100 ml of dry dichloro-
methane was added TBTH (5.82 g, 20.0 mmol) at 0 ЊC. The
reaction mixture was stirred for 2 h, and was then evaporated in
vacuo. Chromatographic separation of the residue (silica gel;
dichloromethane–2–10% methanol) yielded acid 10 (13.2 g,
94%) as a solidified foam, containing slight amounts of tin
impurities.
1
97%) as a solid, H-NMR δ(CD3OD) 2.05 (quin, 4H, CH2-
CH2CH2), 2.93 (t, 4H, NHCH2), 4.10 (t, 4H, ArOCH2), 4.78
(d, 2H, CO CH ), 5.31 (dd, 2H, CH᎐CH ), 6.05 (ddd, 1H,
᎐
2
2
2
CH᎐CH ), 6.82 (t, 1H, ArH), 7.08 (d, 2H, ArH) and 8.19 (s, br,
᎐
2
6H, NH); 13C-NMR δ(CD3OD) 28.3 (CH2CH2CH2), 38.5
(NH2CH2), 66.7 (OCH2), 66.8 (CO2CH2), 107.4 (ArC-H), 109.2
(ArC-H), 118.6 (CH᎐CH ), 133.3 (ArC-CO R), 133.6 (CH᎐
᎐
᎐
2
2
Alternative method. Ester 9 (1.15 g, 1.00 mmol), Pd(PPh3)4
(156 mg, 0.10 mmol) and morpholine (871 mg, 10.0 mmol) in 20
ml of dry dichloromethane were stirred for 24 h. Chromato-
graphic separation yielded acid 10 (327 mg, 30%) as analytically
pure material; 1H-NMR δ(CDCl3) 1.95–2.10 (m, 28H, 8 × CH3,
CH2CH2CH2), 2.50 (m, 4H, COCH2CH2S), 2.95 (m, 4H,
COCH2CH2S), 3.42 (q, 4H, NHCH2), 3.64 (m, 2H, H-5), 4.15
(t, 4H, ArOCH2), 4.18 (m, 4H, H2-6), 4.55 (d, 2H, H-1), 4.90
(m, 4H, H-2 and -4), 5.10 (m, 2H, H-3), 6.40 (br t, 2H, NH),
6.62 (br t, 1H, ArH) and 7.18 (br d, 2H, ArH); 13C-NMR
δ(CDCl3) 20.5, 20.6 and 20.7 (CH3), 26.9 (COCH2CH2S), 28.9
(CH2CH2CH2), 36.7 (CH2NH), 37.4 (COCH2CH2S), 61.9
(C-6), 65.9 (ArOCH2), 68.2 and 69.6 (C-2 and -4), 73.8 (C-3),
76.1 (C-5), 84.4 (C-1), 107.2 and 108.2 (ArC-H), 131.6 (ArC-
CO2H), 159.8 (ArC-O), 169.4 (COCH3), 169.5 (ArCO2H),
170.1 and 170.7 (COCH3) and 171.4 (CONH); (Ϫ)FAB-MS
m/z (%) 1103 (7) [M Ϫ H]Ϫ; [C47H64N2O24S2 (1105.1): Found: C,
50.7; H, 6.1; N, 2.6. Calc. C, 51.08; H, 5.84; N, 2.53%].
CH2), 161.2 (ArC-O) and 167.1 (CO2R); EIMS (80 eV) m/z
(%) 308 (32) [M Ϫ 2HCl]ϩ; HRMS (Found: 308.173 48 [M Ϫ
2HCl]ϩ. C16H24N2O4 requires M, 308.173 61).
3-(2,3,4,6-Tetra-O-acetyl-â-D-glucopyranosylthio)propionic acid
8
A solution of BF3ؒEt2O (7.50 ml, 60.0 mmol) was added drop-
wise to a solution of 1,2,3,4,6-penta-O-acetyl--glucose 6
(20.0 g, 50.0 mmol) and 3-mercaptopropionic acid 7 (5.30 g,
50.0 mmol) in 300 ml of dichloromethane. The reaction mixture
was stirred for 2 h at ambient temperature, washed with 1 M
hydrochloric acid, and dried with magnesium sulfate. After
removal of the solvent in vacuo chromatographic separation
[silica gel; hexane–ethyl acetate (2:1 v/v)] gave title compound 8
(18.8 g, 86%) as a wax-like solid, 1H-NMR δ(CDCl3) 1.97, 2.04,
2.05 and 2.10 (4 s, 12H, CH3), 2.70 (m, 2H, SCH2CH2), 2.91
(m, 2H, SCH2CH2), 3.63 (m, 1H, H-5), 4.20 (m, 2H, H2-6), 4.50
(d, 1H, H-1), 5.03 (m, 2H, H-2, -4), 5.20 (m, 1H, H-3) and 10.24
(br s, 1H, CO2H); 13C-NMR δ(CDCl3) 20.5, 20.6 and 20.7
(CH3), 25.0 (SCH2), 35.1 (CH2CO2H), 62.1 (C-6), 68.2 and 69.6
(C-2 and -4), 73.6 (C-3), 75.7 (C-5), 83.8 (C-1), 169.4, 170.1 and
170.7 (COCH3) and 176.5 (CO2H); (Ϫ)FAB 435 (22) [M Ϫ H]Ϫ;
[C17H24O11S (436.43): Found: C, 46.55; H, 5.4. Calc. C, 46.79;
H, 5.54%].
Allyl 3,5-bis-[3-(3,5-bis-{3-[3-(2,3,4,6-tetra-O-acetyl-â-D-gluco-
pyranosylthio)propionamide]propoxy}benzamido)propoxy]-
benzoate 11
A solution of G-1 carboxylic acid 10 (1.68 g, 1.52 mmol) and
HOBT (0.26 g, 1.70 mmol) in dry dichloromethane (100 ml)
was stirred for 10 min. Amino dendron 5 (0.29 g, 0.75 mmol)
and DBU (0.60 g, 0.59 ml, 3.95 mmol) were added and the
reaction mixture was stirred until the reactants completely dis-
solved. Then EDC (0.33 g, 1.70 mmol) was added. The solution
was stirred for 18 h, then was diluted with 100 ml of dichloro-
methane and washed successively with water and brine. The
organic layer was dried with magnesium sulfate and evapor-
ated. Column chromatography of the oily residue (silica gel;
dichloromethane–3–10% methanol) afforded title ester 11 (1.27
g, 68%) as a solidified foam; 1H-NMR δ(CDCl3) 1.85–2.12 (m,
60H, 16 × CH3, CH2CH2CH2), 2.47 (m, 8H, COCH2CH2S),
2.92 (m, 8H, COCH2CH2S), 3.39 (q, 8H, NHCH2), 3.56–3.72
(m, 8H, H-5, NHCH2), 3.90–4.22 (m, 20H, ArOCH2, H2-6),
4.54 (d, 4H, H-1), 4.79 (d, 2H, CO2CH2), 4.96 (m, 8H, H-2 and
Allyl 3,5-bis-{3-[3-(2,3,4,6-tetra-O-acetyl-â-D-glucopyranosyl-
thio)propionamide]propoxy}benzoate 9
A solution of acid 8 (14.0 g, 37.1 mmol) and HOBT (5.36 g,
35.0 mmol) in dry dichloromethane (500 ml) was stirred for 10
min. G-1 Amino dendron 5 (5.34 g, 14.0 mmol) and DIPEA
(10.9 g, 14.6 ml, 84.0 mmol) were added and the reaction mix-
ture was stirred until the reactants completely dissolved. Then
EDC (6.71 g, 35.0 mmol) was added. The solution was stirred
for 18 h, diluted with 300 ml of dichloromethane, and washed
successively with saturated aq. sodium hydrogen carbonate, aq.
(20%) citric acid and brine. The organic layer was dried with
magnesium sulfate and evaporated. Column chromatography
of the oily residue (silica gel; dichloromethane–2–4% methanol)
afforded title compound 9 (14.7 g, 91%) as a solidified foam,
1H-NMR δ(CDCl3) 1.97–2.10 (m, 28H, 8 × CH3, CH2CH2-
CH2), 2.48 (m, 4H, COCH2CH2S), 2.90 (m, 4H, COCH2CH2S),
3.46 (q, 4H, NHCH2), 3.70 (m, 2H, H-5), 4.09 (t, 4H,
ArOCH2), 4.12 (m, 4H, H2-6), 4.51 (d, 2H, H-1), 4.75 (d, 2H,
CO2CH2), 4.94 (m, 4H, H-2 and -4), 5.10 (m, 2H, H-3), 5.25 (dd,
-4), 5.18 (m, 4H, H-3), 5.30 (dd, 2H, CH᎐CH ), 6.00 (ddd, 1H,
᎐
2
CH᎐CH ), 6.42–6.55 (m, 6H, NHCOCH , ArH), 6.65 (t, 1H,
᎐
2
2
ArH), 6.82 (d, 4H, ArH), 7.08 (br t, 2H, NHCOAr) and 7.13 (d,
2H, ArH); 13C-NMR δ(CDCl3) 20.5, 20.6 and 20.7 (CH3), 26.9
(COCH2CH2S), 28.8 (CH2CH2CH2), 36.7 (CH2NHCOCH2),
37.2 (COCH2CH2S), 37.8 (CH2NHCOAr), 61.9 (C-6), 65.8
(ArOCH2), 66.7 (CO2CH2), 68.3 and 69.6 (C-2 and -4), 73.7
(C-3), 76.0 (C-5), 84.4 (C-1), 104.5, 105.7, 106.9 and 108.1
(ArC-H), 118.4 (CH᎐CH ), 132.1 (CH᎐CH , ArC-CO R),
2H, CH᎐CH ), 5.96 (ddd, 1H, CH᎐CH ), 6.25 (br t, 2H, NH),
᎐
᎐
2
2
6.64 (t, 1H, ArH) and 7.20 (d, 2H, ArH); 13C-NMR δ(CDCl3)
20.5, 20.6 and 20.7 (CH3), 26.8 (COCH2CH2S), 28.8 (CH2CH2-
CH2), 36.8 (NHCH2), 37.3 (COCH2CH2S), 61.8 (C-6), 65.8
(CO2CH2), 65.9 (OCH2), 68.1 and 69.5 (C-2 and -4), 73.7 (C-3),
76.0 (C-5), 84.4 (C-1), 106.5 (ArC-H), 107.9 (ArC-H), 118.4
᎐
᎐
2
2
2
136.8 (ArC-CONH), 159.8 (ArC-O), 160.0 (ArC-O), 165.8
(ArCO2R), 167.4 (ArCONH), 169.4, 170.0 and 170.7 (COCH3)
and 171.3 (CH2CONH); (ϩ)FAB-MS m/z (%) 2482.8 (7)
[M ϩ H]ϩ; [C110H148N6O50S4 (2482.6): Found: C, 52.8; H, 5.85;
N, 3.3. Calc. C, 53.22; H, 6.01; N, 3.39%].
(CH᎐CH ), 132.0 and 132.1 (CH᎐CH , ArC-CO R), 159.8
᎐
᎐
2
2
2
J. Chem. Soc., Perkin Trans. 1, 1999, 501–508
505

View Article Online
3,5-Bis-[3-(3,5-bis-{3-[3-(2,3,4,6-tetra-O-acetyl-â-D-gluco-
pyranosylthio)propionamido]propoxy}benzamido)propoxy]-
benzoic acid 12
THF was added acryloyl chloride (1.53 g, 1.38 ml, 17 mmol)
dropwise. The reaction mixture was stirred at RT for 16 h, then
was extracted successively with saturated aq. sodium hydrogen
carbonate and brine. The organic layer was dried with mag-
nesium sulfate and evaporated in vacuo. Chromatographic
separation (silica gel; dichloromethane) gave title acrylate 13d
To a solution of G-2 allylic ester 11 (880 mg, 0.35 mmol) and
PdCl2(PPh3)2 (5.64 mg, 8.05 µmol) in 20 ml of dry dichloro-
methane was added TBTH (160 mg, 0.55 mmol) at 0 ЊC. The
reaction mixture was stirred for 2 h, and was then evaporated in
vacuo. Chromatographic separation of the residue (silica gel;
dichloromethane–2–10% methanol) yielded title acid 12 (502
mg, 60%) as a solidified foam, containing small amounts of tin
1
(2.68 g, 76%) as an oil; H-NMR δ(CDCl3) 1.42 (s, 9H, CH3),
4.27 (d, 2H, CH2NH), 4.95 (br s, 1H, NH), 5.14 (s, 2H,
CH OR), 5.80 (dd, 1H, CH᎐CH ), 6.11 (dd, 1H, CH᎐CH ),
᎐
᎐
2
2
2
6.40 (dd, 1H, CH᎐CH ), 7.25 (d, 2H, ArH) and 7.31 (d, 2H,
᎐
2
ArH); 13C-NMR δ(CDCl3) 28.3 (CH3), 44.3 (CH2NH), 66.0
1
impurities; H-NMR δ(CDCl3) 1.80–2.15 (m, 60H, 16 × CH3,
(CH OR), 79.4 [C(CH ) ], 121.6 (CH᎐CH ), 128.2 (ArC-H),
᎐
2
3
3
2
CH2CH2CH2), 2.49 (m, 8H, COCH2CH2S), 2.90 (m, 8H,
COCH2CH2S), 3.38 (m, 8H, NHCH2), 3.53–3.75 (m, 8H, H-5,
NHCH2), 3.85–4.20 (m, 20H, ArOCH2, H2-6), 4.58 (d, 4H,
H-1), 4.90–5.05 (m, 8H, H-2 and -4), 5.20–5.30 (m, 4H, H-3),
6.42–6.60 (m, 6H, NHCOCH2, ArH), 6.65 (t, 1H, ArH), 6.85
(d, 4H, ArH), 7.00 (br t, 2H, NHCOAr) and 7.21 (d, 2H,
ArH); 13C-NMR δ(CDCl3) 20.6, 20.7 and 20.8 (CH3), 26.9
(COCH2CH2S), 28.9 (CH2CH2CH2), 29.9 (CH2CH2CH2),
36.9 (CH2NHCOCH2), 37.3 (COCH2CH2S), 38.3 (CH2NH-
COAr), 61.9 (C-6), 65.8 (ArOCH2), 67.3 (ArOCH2), 68.2 and
69.6 (C-2 and -4), 73.7 (C-3), 76.0 (C-5), 84.4 (C-1), 104.7,
105.5, 108.6 and 111.3 (ArC-H), 132.6 (ArC-CO2R), 136.9
(ArC-CONH), 159.7 (ArC-O), 160.0 (ArC-O), 167.4
(ArCONH), 169.4 (COCH3), 169.5 (CO2H), 170.1 and 170.8
(COCH3) and 171.5 (CH2CONH); (ϩ)FAB-MS m/z (%) 2443
(0.3) [M ϩ H]ϩ.
128.5 (ArC-H), 131.0 (CH᎐CH ), 134.8 (ArC-CH OH), 139.1
᎐
2
2
(ArC-CH2NH), 155.8 (NHCO2) and 165.9 (CO2R); MS (80
eV); m/z (%) 237 (0.24) [M]ϩ.
4-(Aminomethyl)benzyl acrylate hydrochloride 13e
Hydrochloric acid (25%; 6.48 ml, 45 mmol) was added to a
solution of the protected acrylate 13d (6.6 g, 23 mmol) in 150
ml of THF. The reaction mixture was stirred at RT for 36 h. The
solvent was evaporated off and the crude product was dissolved
in ethanol. Precipitation with diethyl ether gave 13e (5.43 g,
1
83%) as a solid, H-NMR δ(CD3OD) 4.12 (s, 2H, CH2NH),
5.22 (s, 2H, CH OR), 5.90 (dd, 1H, CH᎐CH ), 6.19 (dd, 1H,
᎐
2
2
CH᎐CH ), 6.40 (dd, 1H, CH᎐CH ) and 7.47 (s, 4H, ArH);
᎐
᎐
2
2
13C-NMR δ(CD3OD) 43.9 (CH2NH), 66.9 (CH2OR), 129.0
(CH᎐CH ), 129.8 (ArC-H), 130.3 (ArC-H), 132.7 (CH᎐
᎐
᎐
2
CH2), 134.4 (ArC-CH2OH), 138.3 (ArC-CH2NH) and 168.0
(CO2R); MS (80 eV) m/z (%) 191 (16.9) [M]ϩ; [C11H14ClNO2
(227.69): Found: C, 57.5; H, 6.2; N, 5.9. Calc. C, 58.03; H,
6.20; N, 6.15%].
4-(tert-Butoxycarbonylaminomethyl)benzoic acid 13b
To a solution of 4-(aminomethyl)benzoic acid 13a (30.0 g, 149
mmol) and potassium hydroxide (8.3 g, 149 mmol) in a mixture
of 600 ml of THF and 100 ml of water, was added di-tert-
butyldicarbonate (39.0 g, 179 mmol) and the mixture was
stirred at RT for 1 h. The layers were separated and the organic
layer was washed with brine, dried with magnesium sulfate, and
evaporated in vacuo. The raw material was dried in vacuo to
4-[(3,5-Bis-{3-[3-(2,3,4,6-tetra-O-acetyl-â-D-glucopyranosyl-
thio)propionamido]propoxy}benzamido)methyl]benzyl acrylate
14
A solution of G-1 carboxylic acid 10 (3.47 g, 3.14 mmol) and
HOBT (0.51 g, 3.30 mmol) in dry dichloromethane (50 ml) was
stirred for 10 min. 4-(Aminomethyl)benzyl acrylate 13e (0.68 g,
3.0 mmol) and DIPEA (0.83 g, 1.11 ml, 6.40 mmol) were added
and the reaction mixture was stirred until the reactants com-
pletely dissolved. Then EDC (0.63 g, 3.30 mmol) was added.
The solution was stirred for 24 h, diluted with 100 ml of di-
chloromethane and washed successively with water and brine.
The organic layer was dried with magnesium sulfate and was
then evaporated. Column chromatography of the oily residue
(silica gel, dichloromethane–2–5% methanol) afforded title
compound 14 (3.53 g, 88%) as a solidified foam, which could be
lyophilized from dioxane; 1H-NMR δ(CDCl3) 1.85–2.10 (m,
28H, CH3, CH2CH2CH2), 2.47 (m, 4H, COCH2CH2S), 2.89 (m,
4H, COCH2CH2S), 3.35 (q, 4H, NHCH2), 3.64 (m, 2H, H-5),
3.90–4.22 (m, 8H, ArOCH2, H2-6), 4.50 (d, 2H, H-1), 4.59 (d,
2H, ArCH2NH), 4.92 (t, 4H, H-2 and -4), 5.10–5.25 (m, 4H,
1
give title acid 13b (35.1 g, 94%) as an oil, H-NMR δ(CDCl3–
CD3OD) 1.30 (s, 9H, CH3), 4.10 (br s, 1H, OH), 4.17 (br s,
1H, NH), 4.60 (s, 2H, CH2), 7.17 (d, 2H, ArH) and 7.82
(d, 2H, ArH); 13C-NMR δ(CDCl3–CD3OD) 27.9 (CH3), 43.7
(CH2NH), 80.4 [C(CH3)3], 126.6 (ArC-H), 129.4 (ArC-H),
129.9 (ArC-CO2H), 143.9 (ArC-CH2), 156.4 (NHCO2) and
169.2 (CO2H); MS (80 eV) m/z (%) 251 (3.8) [M]ϩ; [C13H17NO4
(251.3): Found: C, 61.9; H, 6.8; N, 5.4. Calc. C, 62.12; H, 6.82;
N, 5.57%].
4-(tert-Butoxycarbonylaminomethyl)benzyl alcohol 13c
Lithium aluminium hydride (3.0 g, 78 mmol) was suspended in
250 ml of dry THF. The protected benzoic acid 13b (20.92 g, 78
mmol) was slowly added and the reaction mixture was heated to
40 ЊC for 14 h. The reaction was stopped by addition of water,
and acetic acid was added to give a pH of 5. The layers were
separated and the organic layer was washed with brine. Extrac-
tion of the aqueous layer with diethyl ether was carried out
carefully. The combined organic layers were dried with mag-
nesium sulfate and evaporated in vacuo. The raw material was
dried in vacuo to give title alcohol 13c (11.6 g, 63%) as a solid,
1H-NMR δ(CDCl3) 1.41 (s, 9H, CH3), 2.63 (br s, 1H, OH), 4.29
(d, 2H, CH2NH), 4.63 (s, 2H, CH2OH), 4.80 (br s, 1H, NH),
7.22 (d, 2H, ArH) and 7.33 (d, 2H, ArH); 13C-NMR δ(CDCl3)
28.4 (CH3), 44.4 (CH2NH), 64.8 (CH2OH), 79.5 [C(CH3)3],
127.2 (ArC-H), 127.5 (ArC-H), 138.2 (ArC-CH2OH), 140.1
(ArC-CH2NH) and 155.9 (NHCO2); MS (80 eV) m/z (%) 237
(0.24) [M]ϩ.
H-3, ArCH O), 5.82 (dd, 1H, CH᎐CH ), 6.10 (dd, 1H,
᎐
2
2
CH᎐CH ), 6.34–6.46 (m, 3H, CH᎐CH , CONHCH CH ), 6.48
᎐
᎐
2
2
2
2
(t, 1H, ArH), 6.86 (d, 2H, ArH), 7.08 (br t, 1H, CONHCH2Ar)
and 7.35 (s, 4H, ArH); 13C-NMR δ(CDCl3) 20.5, 20.6 and 20.7
(CH3), 26.9 (COCH2CH2S), 28.7 (CH2CH2CH2), 36.6 (CH2-
NHCOCH2), 37.2 (COCH2CH2S), 43.7 (CONHCH2Ar), 61.8
(C-6), 65.7 (ArCH2OCO), 65.9 (ArOCH2), 68.1 and 69.5 (C-2
and -4), 73.6 (C-3), 75.8 (C-5), 84.4 (C-1), 104.4, 105.8 and
128.0 (ArC-H), 128.2 (CH᎐CH ), 128.5 (ArC-H), 131.1
᎐
2
(CH᎐CH ), 134.8 (ArC-CONH), 136.6 (ArC-CH NH), 138.5
᎐
2
2
(ArC-CH O), 159.9 (ArC-O), 165.9 (CH ᎐CHCO R), 167.1
᎐
2
2
2
(ArCONH), 169.4, 170.0 and 170.6 (COCH3) and 171.0
(CH2CONH); (ϩ)FAB-MS m/z (%) 1316 (0.3) [M ϩ K]ϩ, 1300
(0.6) [M ϩ Na]ϩ, 1278 (3) [M ϩ H]ϩ, 946 (1) [M Ϫ Glu
(C14H19O9)]ϩ, 476 (16) [GluSC2H4CONHC3H6]ϩ and 331 (10)
[Glu (C14H19O9)]ϩ; [C58H75N3O25S2 (1278.3): Found: C, 54.4; H,
5.7; N, 3.0. Calc. C, 54.50; H, 5.91; N, 3.29%].
4-(tert-Butoxycarbonylaminomethyl)benzyl acrylate 13d
To a mixture of the alcohol 13c (2.87 g, 12 mmol), triethylamine
(4.85 g, 6.7 ml, 48 mmol) and DMAP (10 mg) in 100 ml of dry
506
J. Chem. Soc., Perkin Trans. 1, 1999, 501–508

View Article Online
4-({3,5-Bis-[3-(3,5-bis-{3-[3-(2,3,4,6-tetra-O-acetyl-â-D-gluco-
pyranosylthio)propionamido]propoxy}benzamido)propoxy]benz-
amido}methyl)benzyl acrylate 16
7.40 (br s, 1H), 7.48 (br s), 8.00 (br t, 4H), 8.62 (br t, 2H) and
9.05 (br t, 1H).
A solution of G-2 carboxylic acid 12 (472 mg, 0.19 mmol) and
HOBT (46.0 mg, 0.3 mmol) in dry dichloromethane (50 ml) was
stirred for 10 min. 4-(Aminomethyl)benzyl acrylate 13e (68.0 g,
0.3 mmol) and DBU (91.0 mg, 0.60 mmol) were added and the
reaction mixture was stirred until the reactants completely dis-
solved. Then EDC (56.0 mg, 0.3 mmol) was added. The solu-
tion was stirred for 24 h, diluted with 100 ml dichloromethane,
and washed successively with water and brine. The organic layer
was dried with magnesium sulfate and evaporated. Column
chromatography of the oily residue (silica gel; dichloro-
methane–2–10% methanol) afforded title compound 16 (380
mg, 76%) as a solidified foam, which could be lyophilized from
1,4-dioxane, 1H-NMR δ(D7-DMF) 1.91 (m, 8H, CH2CH2CH2),
1.95–2.10 (m, 52H, 16 × CH3, CH2CH2CH2), 2.51 (m, 8H,
COCH2CH2S), 2.93 (m, 8H, COCH2CH2S), 3.32 (m, 8H,
NHCH2CH2), 3.50–3.60 (m, 8H, H-5, NHCH2CH2), 4.00–4.28
(m, 20H, ArOCH2, H2-6), 4.58 (d, 4H, H-1), 4.85–5.07 (m, 10H,
H-2 and -4, ArCH2NH), 5.20 (s, 2H, ArCH2O), 5.32 (m, 4H,
Acknowledgements
This work was supported by the Deutsche Forschungsgemein-
schaft (Graduiertenkolleg “Synthetische, mechanistische und
reaktionstechnische Aspekte von Metallkatalysatoren” and
Sfb 448, TPA1) and the Fonds der Chemischen Industrie,
which is gratefully acknowledged. We thank G. Hertel for her
competent help with some of the experiments.
References
1 For a comprehensive treatment of spherically shaped dendrimers
see: G. R. Newkome, C. N. Moorefield and F. Vögtle, Dendritic
Molecules—Concepts, Syntheses, Perspectives, VCH, Weinheim,
1996.
2 G. R. Newkome, C. N. Moorefield, G. R. Baker, A. L. Johnson and
R. K. Behera, Angew. Chem., Int. Ed. Engl., 1991, 30, 1176.
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Engl., 1995, 34, 1206.
H-3), 5.94 (dd, 1H, CH᎐CH ), 6.32 (dd, 1H, CH᎐CH ), 6.63 (d,
᎐
᎐
2
2
1H, CH᎐CH ), 6.68 (br t, 2H, ArH), 7.11 (br d, 4H, ArH), 7.20
᎐
2
(br d, 2H, ArH), 7.32 (br t, 1H, ArH), 7.40 (br s, 4H, ArH),
7.99 (br t, 4H, NH), 8.61 (br t, 2H, NH) and 9.03 (br t, 1H,
NH); 13C-NMR δ(D7-DMF) 20.4, 20.5 and 20.6 (CH3), 26.7
(COCH2CH2S), 36.5 (CH2CH2CH2), 37.2 (COCH2CH2S), 43.6
(CH2CH2NH), 62.8 (C-6), 64.0 (ArCH2NH), 66.3 (ArOCH2),
66.5 (ArOCH2), 67.4 (CO2CH2), 69.2 and 70.7 (C-2 and -4),
74.1 (C-3), 75.7 (C-5), 83.6 (C-1), 104.4, 104.8, 106.4 and
4 P. Murer and D. Seebach, Angew. Chem., Int. Ed. Engl., 1995, 34,
2116.
5 (a) S. A. DeFrees and F. C. A. Gaeta, J. Am. Chem. Soc., 1993,
115, 7549; (b) E. S. Litscher, K. Juntunen, A. Seppo, L. Penttilä,
R. Renkonen and P. M. Wassarman, Biochemistry, 1995, 34, 4662;
(c) K. H. Mortell, R. V. Weatherman and L. L. Kiessling, J. Am.
Chem. Soc., 1996, 118, 2297; (d) G. B. Sigal, M. Mammen,
G. Dahmann and G. M. Whitesides, J. Am. Chem. Soc., 1996, 118,
3789.
6 (a) Y. C. Lee, R. T. Lee, K. Rice, Y. Ichikawa and T.-C. Wong, Pure
Appl. Chem., 1991, 63, 499; (b) R. Lee and Y. C. Lee, Neoglyco-
conjugates, ed. Y. C. Lee and R. Lee, Academic Press, San Diego,
1994, p. 23.
106.5 (ArC-H), 128.1 (COCH᎐CH ) 128.4 and 129.1 (ArC-H),
᎐
2
131.9 (COCH᎐CH ), 135.6 (ArC-CONH), 137.4 (ArC-CH ),
᎐
2
2
137.6 (ArC-CONH), 140.7 (ArC-CH2), 160.7 (ArC-O), 160.8
(ArC-O), 166.2 (ArCONH), 166.6 (CO2R), 166.8 (ArCONH),
170.0, 170.2, 170.4, 170.9 and 171.1 (COCH3, CH2CONH);
(ϩ)FAB-MS m/z (%) 2616 (0.3) [M ϩ H]ϩ.
7 (a) R. Roy, D. Zanini, S. J. Meunier and A. Romanowska, J. Chem.
Soc., Chem. Commun., 1993, 1869; (b) R. Roy, W. K. C. Park, Q. Wu
and S.-N. Wang, Tetrahedron Lett., 1995, 36, 4377; (c) D. Zanini,
W. K. C. Park and R. Roy, Tetrahedron Lett., 1995, 36, 7383;
(d) R. Roy, Modern Methods in Carbohydrate Synthesis, ed. S. H.
Khan and R. A. O’Neill, Harwood, Amsterdam, 1996, p. 378;
(e) D. Zanini and R. Roy, J. Am. Chem. Soc., 1997, 119, 2088.
8 K. Aoi, K. Itoh and M. Okada, Macromolecules, 1995, 28, 5391.
9 T. K. Lindhorst and C. Kieburg, Angew. Chem., Int. Ed. Engl., 1996,
35, 1953.
10 (a) P. R. Ashton, S. E. Boyd, C. L. Brown, N. Jayaraman, S. A.
Nepogodiev and J. F. Stoddart, Chem. Eur. J., 1996, 2, 1115; (b) P. R.
Ashton, S. E. Boyd, C. L. Brown, N. Jayaraman and J. F. Stoddart,
Angew. Chem., Int. Ed. Engl., 1997, 36, 756; (c) P. R. Ashton, S. E.
Boyd, C. L. Brown, N. Jayaraman, S. A. Nepogodiev, E. W. Meijer,
H. W. I. Peerlings and J. F. Stoddart, Chem. Eur. J., 1997, 3, 974.
11 A. D. Schlüter, Top. Curr. Chem., 1998, Vol. Dendrimers, 165.
12 (a) W. Stocker, B. L. Schürmann, J. P. Rabe, S. Förster, P. Lindner,
I. Neubert and A. D. Schlüter, Adv. Mater., 1998, 10, 793; (b)
W. Stocker, B. Karakaya, B. L. Schürmann, J. P. Rabe and A. D.
Schlüter, J. Am. Chem. Soc., 1998, 120, 7691.
Poly-{4-[(3,5-bis-{3-[3-(2,3,4,6-tetra-O-acetyl-â-D-glucopyrano-
sylthio)propionamido]propoxy}benzamido)methyl]benzyl
acrylate} 15
To a solution of G-1 monomer 14 (0.13 g, 0.10 mmol) in 100 µl
of freshly distilled and degassed benzene was added a freshly
prepared solution of AIBN (100 µl, 0.2 µmol). The reaction
mixture was vigorously stirred in a sealed flask at 55 ЊC for 16 h;
GPC of raw material: 15 (92%): 14 (8% recovery); polymer 15
was isolated by successive precipitation from hexane and water–
methanol (1:1), 1H-NMR δ(3 CD3OD–1 CDCl3) 1.84–2.10 (br
m, 30H), 2.48 (br s, 4H), 2.89 (br m, 4H), 3.25 (br s, 4H), 3.72–
4.00 (br m, 6H), 4.10–4.40 (br m, 6H), 4.50–4.80 (br m, 12H),
4.90–5.02 (br m, 4H), 5.20 (br m, 2H), 6.51 (br s, 1H), 6.90 (br s,
1H) and 7.12 (br s, 1H); 13C-NMR δ(3 CD3OD–1 CDCl3) 20.9,
21.0, 21.1, 27.3, 29.8, 30.3, 37.2, 37.6, 63.0, 66.4, 68.6, 69.3,
70.9, 74.7, 76.4, 82.4, 84.6, 106.7, 128.0, 128.4, 128.6, 137.1,
137.2, 139.7, 160.9, 168.7, 170.7, 171.2, 171.9 and 173.0;
[(C58H75N3O25S2)n (1278.3)n: Found: C, 53.7; H, 5.8; N, 3.1.
Calc. C, 54.50; H, 5.91; N, 3.29%].
13 I. Neubert and A. D. Schlüter, Macromolecules, 1998, 31, 9372.
14 A dendronized polyacrylate without functional groups in the
periphery has also been reported: I. Neubert, R. Klopsch, W.
Claussen and A. D. Schlüter, Acta Polym., 1996, 47, 455.
15 (a) R. Klopsch, S. Koch and A. D. Schlüter, Eur. J. Org. Chem.,
1998, 1275; (b) A. Ingerl, I. Neubert, R. Klopsch and A. D. Schlüter,
Eur. J. Org. Chem., 1998, 2551.
Poly-4-({3,5-bis-[3-(3,5-bis-{3-[3-(2,3,4,6-tetra-O-acetyl-â-D-
glucopyranosylthio)propionamido]propoxy}benzamido)propoxy]-
benzamido}methyl)benzyl acrylate 17
16 M. Elofsson, B. Walse and J. Kihlberg, Tetrahedron Lett., 1991, 32,
7613.
To G-2 monomer 16 (0.05 g, 0.02 mmol) was added a freshly
17 (a) J. C. Sheehan, J. Preston and P. A. Cruickshank, J. Am. Chem.
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molecules, 1997, 30, 4533.
t
prepared solution of BPB (38 µl, 0.04 µmol) in degassed tolu-
ene. The reaction mixture was vigorously stirred in a sealed
flask at 90 ЊC for 16 h; GPC of raw material: 17 (46%): 16 (54%
1
recovery); H-NMR δ(D7-DMF) 1.90–2.15 (m, 60H), 2.58 (m,
8H), 2.90 (m, 8H), 3.35 (m, 8H), 3.48–3.62 (m, 8H), 4.00–4.35
(m, 20H), 4.60 (m, 4H), 4.95–5.12 (m, 10H), 5.20 (br s, 2H),
5.38 (m, 4H), 6.60 (br s, 2H), 7.10 (br s, 4H), 7.32 (br s, 2H),
19 (a) X. Chen, J. S. Dordick and D. G. Rethwisch, Macromolecules,
1995, 28, 6014; (b) B. D. Martin, S. A. Ampofo, R. J. Lindhardt and
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24 S. Förster, I. Neubert, A. D. Schlüter and P. Lindner, Macro-
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21 The rest of the material was monomer.
22 See ref. 13. Note that the relative molecular mass of G-1 acrylate 14
Paper 8/08373H
is in the range of G-2 macromonomers described there.
508
J. Chem. Soc., Perkin Trans. 1, 1999, 501–508