Asymmetric chelated Claisen rearrangements in the presence of chiral ligands--scope and limitations.

Article abstract of DOI:10.1002/1521-3765(20020415)8:8<1954::AID-CHEM1954>3.0.CO;2-X

Claisen rearrangements of glycine crotyl ester enolates in the presence of chelating metal salts and chiral ligands provide ,-unsaturated amino acids in a highly stereoselective fashion. Best results are obtained with electron withdrawing protecting group

Full text of DOI:10.1002/1521-3765(20020415)8:8<1954::AID-CHEM1954>3.0.CO;2-X

FULL PAPER
Synthesis and Self-Assembling Properties of Polymerizable Organogelators
Guijun Wang and Andrew D. Hamilton*[a]
Abstract: In this paper we report the
development of a family of polymer-
izable urea derivatives that are gelators
for organic solvents. The design involves
amino-acid-based urea derivatives con-
taining methacrylate functional groups.
Several of the bis-ureas show excellent
gelation properties in a variety of or-
ganic solvents at very low concentra-
tions (1.5 mm). The self-assembling
properties of these compounds were
studied by X-ray powder diffraction,
optical microscopy, and electronic mi-
croscopy. The molecules self-assemble
into fibrous aggregates as indicated by
scanning electron microscopy. Depend-
ing on the nature of the monomeric unit,
the structure of the aggregates ranges
from small to large fibers and planar
sheets. In polar solvents, the molecules
exhibit multilamellar packing modes.
The organogels can be polymerized by
photoirradiation leading to significant
increases in stability as indicated by
changes in phase-transition tempera-
ture. The morphology of the aggregates
was seen to maintain a similar structure
both before and after irradiation. This
method provides a novel type of poly-
mer with designed self-assembling ar-
chitecture and also affords to a route to
stabilized polymer gels.
Keywords: organogels
¥ polymeri-
zation ¥ self-assembly ¥ supramolec-
ular chemistry ¥ synthesis
complementary hydrogen-bonding groups into the monomer
unit. Ureas are good candidates for this purpose. The hydro-
gen-bonding properties of the urea group have been exten-
sively studied and exploited in various molecular recognition
systems.[5] For example, urea derivatives have been shown to
form extended linear hydrogen-bonding arrays in the solid
state as shown in Figure 1. When combined with other
Introduction
There has been a growing interest in the gelation of organic
solvents by low molecular-weight organic compounds.[1] This
activity is fueled by the potential application of the gels as
novel and functional materials with a level of order imposed
by the interactions of the molecular gelator. Gels are thought
to form through the initial assembly of the gelator molecules
into fibrous nanostructures which then further organize into a
three dimensional lattice, trapping the solvent within the
voids of the network. The gels formed by small organic
molecules in organic solvents are often called physical gels or
organogels. In these systems, the three-dimensional network
is held together by noncovalent forces such as hydrogen
bonding, p p stacking, and van der Waals interactions. The
attraction of self-assembled gel matrices as materials lies in
their ease of formation, their potential for functionalization,
and the presence of large pores throughout the network. In
particular, the self-assembled nanostructures formed by
organogelators may find use as sensor matrices[2] or as
templates for the synthesis of novel or smart materials.[3, 4]
Despite the advances made in supramolecular chemistry,
the prediction of gelation properties for different compound
classes remains difficult. An attractive strategy for imposing a
predictable interaction within the gel is to incorporate
O
O
O
O
O
O
N
H
N
H
N
H
N
H
N
H
N
H
N
H
N
H
N
H
N
H
N
H
N
H
Figure 1. Schematic representation of hydrogen bonding array formed by
bis-ureas.
structural features, this type of hydrogen-bonded self-recog-
nition can lead to good gelation properties for ureas in organic
or aqueous solvents.[6, 7]
Organogels generally suffer from a structural instability
that leads to collapse of the network within the aerogels when
the solvent is removed. In some cases mixtures of supercritical
(sc)CO 2 and organic solvents have been used as the environ-
ment for gel formation.[8] Removal of the solvent under
conditions of low pressure and temperature can lead to the
formation of low-density materials (aerogels)that are highly
porous with extensive cavities throughout the supramolecular
network.[9] We have recently reported a family of fluorinated
[a] Prof. A. D. Hamilton, G. Wang
Department of Chemistry, Yale University
P.O. Box 208107, New Haven, CT 06520-8107 (USA)
Fax : (‡1)203-432-3221
E-mail: andrew.hamilton@yale.edu
1954
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Chem. Eur. J. 2002, 8, No. 8

1954 1961
bis-ureas that gel sc CO2 without the need for co-solvents.[8]
The high vapor pressure of sc CO2 leads to its facile
evaporation as temperature and pressure approach ambient,
leaving the gel matrix unperturbed. The resulting solid has a
density of approximately 0.004 gmLÀ1 and a well-defined
short fibrous network. However, like most aerogels derived
from organogelators, the fluorinated bis-urea foam is fragile
and crumbles on contact. This fragility is almost certainly due
to the weak noncovalent interactions that are the primary
stabilizing forces for the aerogel network. In contrast,
aerogels from polymer gelators are generally more stable
because of their covalent framework.[10] However, this strat-
egy lacks the flexibility of application and subunit structure
that comes from the self-assembly of small molecule subunits.
An ideal approach to stable aerogels might involve
combining the advantages of self-assembling organogels with
those of polymer gels.[10] This could be achieved by first
allowing the gel to self-assemble through noncovalent inter-
actions and then stabilizing the system by polymerization of
latent functional groups within the monomer. The reactive
groups must be positioned so that they are close enough to
cross-link in the self-assembled network and not cause a
disruption in the matrix. If these criteria are met, polymer-
ization of the gel should lead to a material with much
improved stability and mechanical strength.[11] Despite much
effort in the field, there are few readily accessible polymer-
O
O
O
O
H
N
H
H
H
CH3(CH2)n
(CH2)n
N
N
N
O(CH2)13CH3
O(CH2)13CH3
O
O
2
O
O
1, n = 5
2, n = 7
3, n = 3
4, n = 6
O
O
H
N
H
H
H
CH3(CH2)5
N
(CH2)6
N
N
O(CH2)13CH3
O(CH2)13CH3
O
O
O(CH2)nO
O
O
O(CH2)nO
O
O
2
5, n = 2
6, n = 9
7, n = 2
8, n = 9
O
O
H
H
(CH2)6
N
N
O(CH2)9O
O(CH2)9O
O
O
O
2
9
linking chain in bis-ureas, size of the alkyl esters, and
positioning of the methacrylate groups, we prepared a series
of mono- and bis-urea derivatives 1 9. Compounds 1 and 2
contain a single urea linked to a serine alkyl ester, 3 and 4 are
bis-urea/serine derivatives, 5 and 6 link a glutamate ester to a
mono-urea, 7 and 8 are bis-glutamate ester/bis-urea deriva-
tives, and 9 is an aspartic acid derivative with methcrylates at
the end of both chains. All compounds except 9 have mixed
alkyl and methacrylate-containing esters.
14]
izable organogelators.[12
Our approach to this problem involved the design of chiral
polymerizable derivatives that could gel a range of organic
solvents. The polymerizable subunits are based on an amino
acid and bis-urea platform in-
The syntheses of compounds
Schemes 1 3. The serine derivatives 1 4 were synthesized
1
9
are shown in
corporating methacrylate func-
tional groups. We had earlier
O
EDCI,
O
O
BocHN
DMAP
BocHN
BocHN
H2, Pd/C
OH
OBn
10
OR
OH
shown that bis-urea derivatives
could function either as molec-
ular hosts for dicarboxylic
guests[5a] or as organogelat-
ors,[7a] depending on the nature
of the backbone. In this paper,
we describe the preparation of
a series of derivatives based on
this strategy, and show that they
are versatile gelators for organ-
ic solvents at very low concen-
tration and the gels are signifi-
cantly stabilized by polymeriza-
tion.
OR
OBn
11
ROH
12
Cl
1.
Py, CH2Cl2
O
2. TFA, CH2Cl2
O
O
XHN
OR
CH3(CH2)nNCO
OCN(CH2)nNCO
1, n = 5
2, n = 7
3, n = 6
4, n = 12
O
13, X= Boc
14, X = H
R= (CH2)13CH3
Scheme 1. Synthesis of serine derivatives 1 4.
from the tBoc, benzyl-protected amino acid by esteri-
fication with tetradecanol and debenzylation by hydro-
genation. The hydroxyl group was re-esterified using meth-
acryloyl chloride to give the tBoc protected derivatives.
Deprotection and reaction of the free amine with the
corresponding isocyanate gave the desired urea derivatives.
Formation of the urea as the last step in the synthetic route
avoided the problems of poorly soluble intermediates. Similar
routes were used to prepare the glutamate and aspartate
derivatives.
Results and Discussion
Synthesis: Three key features were incorporated into the
polymerizable organogelator design: the urea hydrogen
bonding motif, one or more alkyl chains, and the methacrylate
groups. Ureas tend to be highly crystalline, which is an
unsuitable property for gel formation. However, introduction
of long chain alkyl ester and/or methacrylate groups should
increase the solubility of the molecule in nonpolar solvents. To
test the relative importance of number of ureas, length of the
Chem. Eur. J. 2002, 8, No. 8
¹ WILEY-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002
0947-6539/02/0808-1955 $ 20.00+.50/0
1955

A. D. Hamilton and G. Wang
FULL PAPER
identical hydrocarbon tails and
the overall symmetry of 9 ap-
pear to make it a poorer gelator
compared to the compounds
containing two different alkyl
ester chains.
O
O
O
BocHN
BocHN
BocHN
OH
OR
EDCI, DMAP
ROH
OR
OH
H2, Pd/C
OBn
O
O
O
OBn
17
16
15
O
HO(CH ) O
1.
2 n
n = 2, 9
Stabilization of the gel on poly-
merization: The effect of light-
induced polymerization on the
gels and their thermal stability
was assessed at 0.5% and 1%
wt concentrations in ethyl ace-
tate. The melting point of the
gels was measured before and
after polymerization by using
the dropping ball method (Ta-
ble 2).[5a] Polymerization was
carried out with a 500 W Hg
lamp, and the extent of cross-
linking was monitored by ob-
serving the disappearance of
the alkene 1H NMR resonances
at d ꢀ 6.0 and 5.5 ppm. Interest-
ingly, the ease with which the
ureas underwent polymeriza-
tion varied with their structures.
Compounds 7 and 8 were fully
2. TFA, CH2Cl2
O
XHN
OR
CH3(CH2)5NCO
OCN(CH2)12NCO
5, n = 2
6, n = 9
7, n = 2
8, n = 9
O
O(CH2)nO
O
18, n = 2, X = Boc
19, n = 9, X = Boc
20, n = 2, X = H
21, n = 2, X = H
R= (CH2)13CH3
Scheme 2. Synthesis of glutamic acid derivatives 5 8.
O
O
BocHN
O
O
O
1.HO(CH2)9O
OH
OH
NCO(CH2)12NCO
XHN
O(CH2)9O
O
9
2. TFA, CH2Cl2
O(CH2)9O
O
22
Scheme 3. Synthesis of aspartic acid derivative 9.
23, X = Boc
24, X = H
Table 2. Thermal stability of the ethyl acetate gels before and after
polymerization by melting point measurement.
Gelation properties: The gelation properties of compounds
9 were tested in a range of solvents, and the results are
1
7
7
8
8
collected in Table 1. In general, the bis-ureas were found to be
more effective organogelators than the corresponding mono-
urea derivatives. This was true for a variety of organic
solvents, including alkanes, esters, alcohols, and acetone. The
gelation usually occurred at room temperature at concen-
trations of urea derivative as low as 0.2% wt. The bis-ureas
have lower solubility compared to the mono-ureas and in
some cases heating was required to fully dissolve them. The
glutamic acid derivatives form more stable gels than the serine
derivatives. Compound 9, with methacrylate groups at the end
of both long chain alkyl esters, showed greater solubility than
the other bis-ureas. This is consistent with the branched
methacrylate group influencing hydrocarbon packing and
increasing chain randomness. However, the presence of two
[5 mgmLÀ1
]
[10 mgmLÀ1
]
[5 mgmLÀ1
]
[10 mgmLÀ1
]
before [8C]
after [8C]
34
40
36
39
> 110
> 110
> 110
> 110
polymerized after 2 4 hours of irradiation, whilst 4 required
approximately 6 8 hours for complete reaction. Compound 3
only forms a gel in ethanol with fast cooling or by sonication.
The gel was not stable to the addition of the radical initiator or
to mechanical shaking, with the compound precipitating out
of the solution. This effect is presumably related to the
relative structural flexibility of the compounds. Glutamic acid
represents a more flexible linker, relative to serine, and the
glutamate/ureas may be better
able to conformationally ac-
Table 1. Gelation properties of compounds 1 9 in organic solvents at room temperature.[a]
commodate intrasubunit cross-
linking. The serine derivatives
are more rigid and this may
decrease the ability of the
methacrylate groups to adopt
an optimal position for reac-
tion.
Hexane
Ethyl acetate
Chloroform
Acetone
EtOH
Ethylene glycol
1
2
3
4
5
6
7
8
9
S
S
S
S
S
S
S
S
S
S
S
S
S
S
S
S
S
G (2.5)/C
I/C
G (3)G (5)
G (10)G (8)
S
S
G (2.5)G (2.5)
G (2)G (2)
I
G (/1P0)G (10)I
G (10) G (4) I/C
S
S
S
S
S
S
I/C
I/C
With compound 7 the melt-
ing point of the gel in ethyl
acetate after polymerization
was >1108C at concentrations
G (2.5) G (2.5) I
G (2.5G) (2) I
S
S
S
I
[a] G: gel, S: soluble (> 20 mgmLÀ1), I: insoluble upon heating, P: precipitation, C: crystallization. The value
given in parentheses is the minimum concentration in mgmLÀ1 to achieve gelation at room temperature.
of 5 mgmLÀ1 and 10 mgmLÀ1
;
1956
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Chem. Eur. J. 2002, 8, No. 8

Polymerizable Organogelators
1954 1961
this temperature is significantly above the boiling point of
ethyl acetate (778C). Heating to 1108C caused little change in
the appearance of the gel with no shrinkage or loss of solvent.
The melting point of the gels after polymerization seems to be
somewhat independent of concentration perhaps due to the
strength of covalent bonding compensating for the concen-
tration effect. A similar increase in stability has recently been
reported for a gelator based on (1R,2R)-trans-1,2-bis(ure-
ido)cyclohexane. In that case polymerization gave a thermo-
stability change at a concentration of 10 mgmLÀ1 in butyl
acetate from 808C to 1358C, an increase of 558C.[13a]
Morphology studies: Scanning electron and optical micros-
copy were used to investigate the morphologies of the
aggregates. The various urea derivatives in this investigation
gave rise to gels of widely differing morphologies, from sheets
to ribbons and fibers. However, the morphology of the gels
did not change significantly after polymerization. Clusters of
ribbonlike structures are formed by compound 8 in ethyl
acetate (Figure 2a)that after polymerization (Figure 2b)
Figure 3. SEM images of the dried gels formed by compound 7 in ethyl
acetate: a)and b)are before polymerization, c)and d)are after
polymerization. The scale bar represents 20 mm in a) , 1mm in b) , 5mm in
c), and 1 mm in d) .
Figure 2. SEM images of the dried gels formed by compound 8 in ethanol:
a)before polymerization, b)after polymerization. The scale bar represents
20 mm in a)and 10 mm in b) .
Figure 4. SEM images of the dried gels formed by compound 3 in ethanol:
a)at low magnification, b)at high magnification. The scale bar represents
10 mm in a)and 1 mm in b) .
retain essentially the same morphology with somewhat
smoother surfaces. Similarly, compound 7 in ethyl acetate
forms a material composed of bundled ribbons that are little
affected by polymerization (Figure 3a,c). At high magnifica-
tion (Â10000)the individual bundles are seen to be composed
of aggregated fibers (Figure 3b,d). The morphologies of the
areogels formed by compound 3 in ethanol correspond to long
intertwined fibers (Figure 4a,b), with an individual diameter
of about 0.5 mm and length of approximately 200 mm. When
dissolved in ethylene glycol, serine mono-urea 2 formed
unstable gels which crystallize on standing. An optical micros-
copy study of these aggregates indicated typical lamellar
packing structures (Figure 5). Monoureas 1, 2, and 5, with a
shorter link between the methacrylate and the amino acid
backbone, formed highly birefringent images under polarized
Chem. Eur. J. 2002, 8, No. 8
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1957

A. D. Hamilton and G. Wang
FULL PAPER
the major peaks observed are collected in Table 3. In
particular, distinct interchain distances of 3 5 ä were ob-
served. In the case of certain bis-ureas, however, only
reflections corresponding to the layer separation could be
seen. This suggests a low crystallinity (high fluidity)among
the hydrocarbon chains as compared to the mono-ureas. For
mono-ureas, such as 1, 2, 5, and 6, relatively high crystallinity
is observed, with the components packing more tightly than
the corresponding bis-urea. These properties mirror the
gelation properties of the molecules, again indicating that
the gel state is intermediate between liquid and crystal phases.
When the crystallinity of the system is high, as with the mono-
urea, solvent encapsulation is low, leading to poorer gelation
properties. When the hydrocarbon chains are more flexible,
subunit packing is less dense and as a result more solvent
molecules can be entrapped within the intranetwork cavities
leading to better gelation properties.
In a mixture of water and ethanol, mono-ureas 1, 2, 5, and 6
can self-assemble into well-organized planar sheets, ribbons,
and fibers. The optical micrographs reveal that the molecules
adopt ordered lamellar structures, in agreement with the
XRD data. An effort was made to determine the X-ray
diffraction pattern of the gel state, and a distance correspond-
ing to the layer length could be observed. As shown in Table 3,
the general trend was that the gels give fewer reflections than
solids, consistent with the decreased order within the gel. In
this study, compound 8 showed the best gelation property
among all of the mono- and bis-urea derivatives. The
morphology of the areogel is somewhat different from a
fibrous-type aggregate, instead adopting a smooth planar
sheet or ribbon structure. There appears to be an important
requirement for two urea functional groups attached to long
alkyl chains for effective gelation. The mono-ureas have
higher crystallinity and show liquid crystalline properties, but
are not good gelators. Possibly, the smaller size and greater
rigidity of the mono-ureas inhibit them from forming three-
dimensional networks. The bis-urea glutamate derivatives
contain one long chain and one shorter chain and show better
gelation properties than the corresponding serine derivatives
perhaps due to the increased rigidity of the latter.
Figure 5. Optical micrographs of the mono-ureas by polarized light:
a)compound 1 in ethylene glycol, b)compound 6 from ethanol/water
(10%).
light (Figure 5a), indicating an ordered, crystalline arrange-
ment. Analysis of the samples by SEM showed them to
contain fibrous ribbons and sheets. The spherulite structures
formed by these compounds are dependent on the chirality of
the self-assembling molecules, as is typical for many chiral
liquid crystalline phases.[15] In contrast, the mono-ureas with a
longer link between the methacrylate and amino acid (com-
pounds 6 and 8)show the characteristic Maltese cross formed
by structures that pack in a lamellar arrangement (Figure 5 b).
Generally, polar solvents were necessary to observe these
structures.
Structure determination by X-ray diffraction (XRD): The
molecular packing of the gelators prior to polymerization was
studied by wide-angle X-ray powder diffraction. Good
diffraction patterns were obtained for the mono-ureas and
Conclusion
We have designed and synthesized a family of polymerizable
organogelators. The bis-ureas synthesized were found to be
excellent organogelators with optimal properties being shown
by the glutamic acid bis-urea derivatives. These molecules
form gels at concentrations as low as 0.2% wt in a variety of
solvents. Furthermore, irradiation with UV light leads to
polymerization and stabilization of the gels. The self-assem-
bled structure and morphologies of these compounds were
studied by using electronic and optical microscopy and X-ray
powder diffraction. The SEM of the areogels showed fibrous
and sheetlike morphologies depending on the structure of the
gelators, the solvent, and the concentration. In more polar
solvents and at lower concentrations, the fibrous structures
are well resolved. At higher concentrations, only flat sheetlike
ribbons or bundles are observed. The X-ray powder diffrac-
Table 3. Major peaks in the XRD pattern for compounds 1 9.
d-spacing [ä]
1
solid: 31.32, 18.48, 15.66, 12.38, 10.35, 5.17, 4.44, 4.05, 3.91; gel: 31.40,
15.72
2
3
solid: 32.71, 16.18, 9.51, 4.52, 4.10, 3.94, 3.63
solid: 32.97, 19.99, 16.48, 13.27, 11.02, 9.93, 8.25, 7.95, 6.61, 5.48, 4.07,
3.96
4
5
6
7
8
9
solid: 20.1; gel: 20.2
solid: 19.2, 12.9, 9.84, 8.79, 6.61, 4.96, 4.49, 4.28, 3.84, 3.58
solid: 33.5, 16.4, 12.5, 10.8, 6.64, 4.12, 3.90, 3.73
solid: 28.3, gel: 23.9
solid: 34.2, gel: 31.3, 25.8
none observed
1958
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0947-6539/02/0808-1958 $ 20.00+.50/0
Chem. Eur. J. 2002, 8, No. 8

Polymerizable Organogelators
1954 1961
M.p. 59.0 60.08C; 1H NMR (500 MHz, CDCl3): d ˆ 6.07 (s, 1H), 5.57 (s,
1H), 5.28 (s, 1H), 4.60 (s, 1H), 4.42 (m, 2H), 4.15 (m, 2H), 1.90 (s, 3H), 1.60
(m, 2H), 1.43 (s, 9H), 1.23 (brs, 24H), 0.86 (t, J ˆ 6.94 Hz, 3H); 13C NMR
(125 MHz, CDCl3): dˆ169.8, 166.6, 155.1, 135.6, 126.2, 80.2, 66.0, 64.8, 53.0,
31.8, 29.6, 29.6, 29.5, 29.4, 29.3, 29.1, 28.4, 28.2, 25.7, 22.6, 18.1, 14.0; HRMS
tion data are consistent with the gelation properties, with
higher crystallinity indicating poorer gelation. The presence
of a long alkyl chain is essential for effective gelation. In
general, incorporation of branched methacrylate groups leads
to disruption of the packing of the hydrocarbon tail and an
increase in solubility. Upon polymerization, the bis-ureas
show increased thermal stability at temperatures above the
boiling point of the solvent. The mono-ureas showed inter-
esting liquid crystalline phases observed by optical micros-
copy under crossed polarizers.
‡
(FAB)calcd for C 21H40NO4 [M ‡H À Boc]: 370.2957; found: 370.2955.
(2S)-2-Amino-3-oxo-3-(tetradecyloxy)propyl 2-methylacrylate (14): The
free amine of the serine derivative was not stable. It was generally not
isolated before the next step. The tBoc-protected compound was depro-
tected with TFA in dichloromethane at 0 108C, the solvent was removed,
and the residue was dried using a vacuum pump for 24 h before coupling
with the bis-isocyanate. The spectroscopic data of the TFA salt of 14:
1H NMR (500 MHz, CDCl3): d ˆ 6.10 (s, 1H), 5.60 (s, 1H), 4.63 (m, 2H),
4.40 (s, 1H), 4.18 (m, 2H), 1.86 (s, 3H), 1.61 (m, 2H), 1.23 (s, 24H), 0.85 (t,
J ˆ 7.25 Hz, 3H); 13C NMR(125 MHz, CDCl3): d ˆ 166.8, 166.7, 134.8, 127.6,
67.6, 61.8, 52.8, 31.9, 29.7, 29.6, 29.6, 29.4, 29.3, 29.1, 28.2, 25.6, 22.7, 17.8, 14.0.
Experimental Section
Gelation: A weighed amount of each compound was mixed with a
measured volume of selected solvents. Generally, low heating or sonicating
are necessary to dissolve the sample, after which it was cooled to room
temperature for 30 minutes. Gelation was determined by the absence of
flow of the solvent when the vial was inverted.
(2S)-2-{[(Hexylamino)carbonyl]amino}-3-oxo-3-(tetradecyloxy)propyl
2-methylacrylate (1): Compound 13 (0.18 g, 0.38 mmol)was deprotected by
the same procedure as above. Triethylamine (0.08 mL, 0.7 mmol)and
hexylisocynate (0.049 g, 0.38mmol)were added to amine 14 in dichloro-
methane at 08C. The reaction was stirred in an ice bath under nitrogen for
24 h. Then the mixture was concentrated, and the residue was taken up in
dichloromethane and washed with water three times. The organic layer was
dried over sodium sulfate, and the solvent was removed to give the crude
product. This was purified by flash chromatography (hexane/acetate 4:1)to
give a white crystalline material (0.17 g, 89%). M.p. 59.5 60.58C; 1H NMR
(500 MHz, CDCl3): d ˆ 6.05 (s, 1H), 5.55 (m, 1H), 5.15 (s, 1H), 4.79 (s, 1H),
4.48 (dd, J ˆ 3.79, 11.37 Hz, 1H), 4.40 (dd, J ˆ 3.28, 11.37 Hz, 1H)4.12 (m,
2H), 3.14 (t, J ˆ 7.07 Hz, 2H), 1.89 (s, 3H), 1.60 (m, 2H), 1.46 (m, 2H),
1.30 1.21 (m, 28H), 0.86 (m, 6H); 13C NMR (125 MHz, CDCl3): d ˆ 170.9,
166.8, 157.2, 135.7, 126.1, 65.96, 65.2, 52.3, 40.6, 31.9, 31.5, 30.0, 29.6 (m),
29.5, 29.4, 29.3, 29.2, 28.5, 26.5, 25.7, 22.6, 22.5, 18.1, 14.1, 14.0; HRMS
Electron microscopy: A small piece of gel was deposited onto a cleaned
glass slide, which was then dried in the air under vacuum. The slides were
coated with carbon and imaged using a JEOL JXA-8600 electron microprobe
with an accelerating voltage of 15 kVand an emission current of 100 500 pA.
Synthesis: The compounds in this study were synthesized by similar
procedures. Details are given for the first example of each class. Particular
caution was taken to avoid the decomposition of the methacrylate
containing compounds.
Tetradecyl (2S)-3-(benzyloxy)-2-[(tert-butoxycarbonyl)amino]propanoate
(11): N-tBoc-O-Benzyl-l-serine 10 (2.95 g, 0.01 mol), 1-tetradecanol
(2.40 g, 0.011 mol), and dimethylamino pyridine (0.12 g, 0.001 mol) were
added to dry dichloromethane (50 mL). The mixture was cooled in an ice
bath and protected from moisture by using a calcium chloride drying tube.
1,[3-(dimethylamino)propyl]-3-ethylcarbodiimide hydrochloride (EDCI)
(2.10 g, 0.011 mol)was added to the cooled mixture, and the reaction was
stirred for 6 8 h, after which time the esterification was complete as
indicated by TLC. The reaction mixture was concentrated to dryness, taken
up in ethyl acetate, and washed with water three times. The organic layer
was dried over sodium sulfate, and the solvent was removed to yield a white
solid (5.00 g). The crude mixture was purified by flash chromatography
(hexane/acetate 9:1)to give pure product as a white crystalline solid
(4.82 g, 98%). M.p. 34.5 35.58C; 1H NMR (500 MHz, CDCl3), d ˆ 7.34
7.24 (m, 5H), 5.38 (d, J ˆ 8.51 Hz), 4.49 (m, 2H), 4.40 (m, 1H), 4.12 (m,
2H), 3.86 (m, 1H), 3.67 (m, 1H), 1.58 (m, 2H), 1.43 (s, 9H), 1.23 (brs, 24H),
0.83 (t, J ˆ 6.94 Hz, 3H); 13C NMR (125 MHz, CDCl3): d ˆ 170.7, 155.4,
137.6, 128.3, 127.7, 127.5, 79.8, 73.2, 70.1, 65.6, 54.0, 31.9, 29.6, 29.5,29.5, 29.3,
29.2, 28.5, 29.3, 25.8, 22.6, 14.1; HRMS (FAB)calcd for C 29H50NO5
‡
(FAB)cacld for C 28H53N2O5 [M ‡H]: 497.3954; found: 497.3953.
(2S)-2-{[(Octylamino)carbonyl]amino}-3-oxo-3-(tetradecyloxy)propyl
2-methylacrylate (2): The product was obtained as a white crystalline solid
(96% from 13)after purification by flash chromatography (hexane/ethyl
acetate 3:1). M.p. 63.0 63.58C; 1H NMR (500 MHz, CDCl3): d ˆ 6.05 (s,
1H), 5.54 (s, 1H), 5.28 (d, J ˆ 7.88 Hz, 1H), 4.80 (m, 2H), 4.69 (s, 1H), 4.80
(m, 1H), 4.69 (m, 1H), 4.47 (dd, J ˆ 4.10, 11.35Hz, 1H), 4.38 (dd, J ˆ 3.47,
11.35 Hz, 1H), 4.12 (m, 2H), 3.12 (m, 2H), 1.88 (s, 3H), 1.59 (m, 2H), 1.45
(m, 2H), 1.40 1.20 (m, 28H), 0.85 (m, 6H); 13C NMR (125 MHz, CDCl3):
d ˆ 170.8, 166.8, 157.1, 135.7, 126.2, 66.0, 65.2, 52.65, 40.7, 31.9, 31.8, 30.0,
29.6(4), 29.5, 29.3, 29.3, 29.2, 28.5, 26.8, 25.8, 22.7, 22.6, 18.2, 14.1, 14.0;
‡
HRMS (FAB)calcd for C 30H57N2O5 [M ‡H]: 525.4267; found: 525.4270.
Ditetradecyl
(2S,15S)-2,15-bis[(methacryloyloxy)methyl]-4,13-dioxo-
3,5,12,14-tetraazahexadecane-1,16-dioate (3): The product was obtained
as a white crystalline solid (93% from 13)after purification by flash
chromatography (hexane/acetone/dichloromethane 8:3:9). M.p. 100.5
101.58C; 1H NMR (400 MHz, CDCl3): d ˆ 6.05 (s, 2H), 5.60 (m, 2H),
5.54 (m, 2H), 5.06 (m, 2H), 4.82 (m, 2H), 4.48 (m, 2H), 4.38 (m, 2H), 4.12
(m, 4H), 3.14 (m, 4H), 1.88 (brs, 6H), 1.60 (m, 4H), 1.45 (m, 4H), 1.23 (s,
48H), 0.88 (t, J ˆ 6.44 Hz, 6H); 13C NMR (100 MHz, CDCl3): d ˆ 171.2,
166.8, 157.7, 135.7, 126.1, 65.92, 65.36, 52.47, 39.71, 31.87, 29.65, 29.63, 29.61,
29.57, 29.52, 29.47, 29.32, 29.21, 28.48, 25.80, 25.77, 22.64, 18.14, 14.06;
‡
[M ‡H]: 492.3689; found: 492.3689.
Tetradecyl
(2S)-2-[(tert-butoxycarbonyl)amino]-3-hydroxypropanoate
(12): Pd/C catalyst (0.25 g)was added to compound 11 (2.46 g, 5.0 mmol)
in ethanol (100 mL), and the mixture was stirred under one atmosphere of
hydrogen for 24 h. The catalyst was removed by filtration through celite.
The solution was concentrated, and the sample was further dried under
vacuum for 12 h to give a colorless crystalline material (2.00 g, 99%). M.p.
‡
HRMS (FAB)cacld for C 50H91N4O10 [M ‡H]: 907.6735; found: 907.6734.
1
32.5 33.58C; H NMR (500 MHz, CDCl3): d ˆ 5.44 (s, 1H), 4.34 (s, 1H),
Ditetradecyl
(2S,21S)-2,21-bis[(methacryloyloxy)methyl]-4,19-dioxo-
4.14 (t, J ˆ 6.62 Hz, 2H), 3.91 (m, 2H), 2.38 (s, 1H; OH), 1.62 (m, 2H), 1.43
(s, 9H), 1.23 (s, 24H), 0.85 (t, J ˆ 7.25 Hz, 3H); 13C NMR (125 MHz,
CDCl3): d ˆ 170.8, 155.8, 80.3, 67.0, 63.8, 55.8, 31.9, 29.7, 29.6, 29.5, 29.5,
29.3, 29.2, 28.5, 28.3, 25.8, 22.7, 14.1; HRMS (FAB)calcd for C 22H44NO5
3,5,18,20-tetraazadocosane-1,22-dioate (4): The product was obtained in
89% yield from 13 as a white solid after purification by flash chromatog-
raphy (hexane/acetone/dichloromethane 4:1:5). M.p. 84.5 85.58C;
1H NMR (500 MHz, CDCl3): d ˆ 6.04 (m, 2H), 5.53 (m, 2H), 5.46 (d, J ˆ
7.25 Hz, 2H), 4.92 (s, 2H), 4.80 (m, 2H), 4.46 (dd, J ˆ 3.94, 11.03 Hz, 2H),
4.37 (dd, J ˆ 3.47, 11.03 Hz, 2H), 4.10 (m, 4H), 3.11 (t, J ˆ 6.31, 4H), 1.87 (s,
6H), 1.58 (m, 4H), 1.44 (m, 4H), 1.22 (m, 60H), 0.85 (t, J ˆ 6.94 Hz, 6H);
13C NMR (125 MHz, CDCl3): d ˆ 170.9, 166.8, 157.3, 135.7, 126.1, 65.9, 65.3,
52.6, 40.6, 31.9, 30.0, 29.6, 29.6, 29.5, 29.5, 29.3, 29.2, 29.1, 28.5, 26.8, 25.8,
‡
[M ‡H]: 402.3219; found: 402.3221.
(2S)-2-[(tert-Butoxycarbonyl)amino]-3-oxo-3(tetradecyloxy)propyl
2-methylacrylate (13): Compound 11 (2.0 g, 5.0 mmol)was dissolved in
pyridine (1 mL)and dry dichloromethane (50 mL,) and the mixture was
cooled to 08C in an ice bath. Methacryloyl chloride (0.53 mL, 5.5 mmol)
was added to the mixture under dry nitrogen. The reaction mixture was
stirred under N2 for 6 h. The mixture was poured into ice (20 g)and
extracted with dichloromethane three times. The combined organic phase
was dried over sodium sulfate, and the solvent was removed on a rotary
evaporator. The crude product was purified by flash chromatography
(hexane/acetate 12:1)to give the product as a white solid (2.10 g, 90%).
‡
22.6, 18.1, 14.1; HRMS (FAB)cacld for C 56H103N4O10 [M ‡H]: 991.7674;
found: 991.7675.
5-Benzyl 1-tetradecyl (2S)-2-[(tert-butoxycarbonyl)amino]pentanedioate
(16): N-tBoc-l-Glutamic g-benzyl ester 15 (3.37 g, 0.010 mol), tetradecanol
(2.35 g, 0.011 mol), and DMAP (0.20 g, 1.6 mmol) were dissolved in 50 mL
Chem. Eur. J. 2002, 8, No. 8
¹ WILEY-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002
0947-6539/02/0808-1959 $ 20.00+.50/0
1959

A. D. Hamilton and G. Wang
FULL PAPER
of dichloromethane. The mixture was cooled in an ice bath to 08C, EDCI
(2.10 g, 0.011 mol)was added, and the reaction mixture was stirred for 6 h in
the ice bath. The work up was similar as before. The solution was concentrated
to dryness, and the residue was taken up in ethyl acetate and washed with
water three times. The organic phase was dried over sodium sulfate, and the
solvent was removed to give the product as a white crystalline solid (5.20 g,
98%)after purification by flash chromatography (hexane/ethyl acetate
6:1). M.p. 47.0 48.08C; 1H NMR (500 MHz, CDCl3): d ˆ 7.24 7.40 (m,
5H), 5.17(d, J ˆ 7.57 Hz, 1H), 5.08 (s, 2H), 4.30 (s, 1H), 4.08 (t, J ˆ 6.78 Hz,
2H), 2.42 (m, 2H), 2.17 (m, 1H), 1.94 (m, 1H), 1.59 (m, 2H), 1.40 (s, 9H),
1.23 (s, 22H), 0.85 (t, J ˆ 6.94 Hz, 3H); 13C NMR (125 MHz, CDCl3): d ˆ
172.3, 172.1, 155.2, 135.7, 128.4, 128.1, 79.7, 66.3, 65.5, 52.8, 31.8, 30.2, 29.5,
29.4, 29.3, 29.2, 29.1, 28.4, 28.1, 27.7, 25.7, 22.5, 14.0; HRMS (FAB)calcd for
1.63 (m, 2H), 1.20 1.30 (m, 22H), 0.85 (t, J ˆ 6.78 Hz, 3H); 13C NMR
(125 MHz, CDCl3): d ˆ 173.6, 168.8, 167.9, 135.6, 126.8, 67.7, 63.4, 62.1, 53.0,
31.9, 29.9, 29.6, 29.5, 29.4, 29.3, 29.1, 28.2, 25.6, 24.8, 22.6, 18.0, 14.0.
5-[2-(Methacryloyloxy)ethyl] 1-tetradecyl (2S)-2-{[(hexylamino)carbonyl]-
amino}pentanedioate (5): The product was obtained as white crystals (90%
from 18)after flash chromatography (hexane/acetate 3:1.) M.p. 45.0
46.08C; 1H NMR (500 MHz, CDCl3): d ˆ 6.10 (m, 1H), 5.57 (q, J ˆ
1.58 Hz, 1H), 5.07 (d, J ˆ 7.88 Hz, 1H), 4.63 (s, 1H), 4.47 (m, 1H), 4.25
4.35 (m, 2H), 3.12 (t, J ˆ 7.25 Hz, 2H), 2.42 (m, 2H), 2.15 (m, 1H), 1.92 (m,
4H), 1.60 (m, 2H), 1.45 (m, 2H), 1.20 1.34 (m, 28H), 0.85 (m, 6H);
13C NMR (125 MHz, CDCl3): d ˆ 173.1, 172.9, 157.5, 135.9, 126.1, 65.7, 62.3,
52.5, 40.6, 31.9, 31.5, 30.2, 30.1, 29.6, 29.6, 29.5, 29.3, 29.2, 28.5, 28.0, 26.5,
25.8, 22.7, 22.5, 18.2, 14.1, 14.0; HRMS (FAB)calcd for C 32H59N2O7
‡
C31H52NO6 [M ‡H]: 534.3795; found: 534.3795.
‡
[M ‡H]: 583.4322; found: 583.4324.
(4S)-4-[(tert-Butoxycarbonyl)amino]-5-oxo-5-(tetradecyloxy)pentanoic
acid (17): Compound 16 (3.00 g, 0.056 mol)was dissolved in ethanol
(100 mL), Pd/C (0.25 g) catalyst was added to the solution, and the mixture
was stirred under one atmosphere of hydrogen for 24 h. The catalyst was
removed by filtration through celite. The filtrate was concentrated to
dryness, and the sample was further dried under vacuum for 12 h to give a
colorless crystalline solid (2.42 g, 97%). M.p. 49.0 50.08C; 1H NMR
(500 MHz, CDCl3): d ˆ 5.16 (s, 1H), 4.32 (s, 1H), 4.11 (t, J ˆ 6.78 Hz, 2H),
2.45 (m, 2H), 2.29 (m, 1H), 1.82 (m, 1H), 1.62 (m, 2H), 1.42 (m, 9H), 1.24
(m, 22H), 0.86 (t, J ˆ 6.94 Hz, 3H); 13C NMR (125 MHz, CDCl3): d ˆ 177.8,
172.2, 155.5, 80.1, 65.8, 52.8, 31.9, 30.1, 29.6, 29.5, 29.4, 29.2, 28.5, 28.2, 27.8,
5-[9-(Methacryloyloxy)nonyl] 1-tetradecyl (2S)-2-{[(hexylamino)carbonyl]-
amino}pentanedioate (6): The product was obtained as white crystals (92%
from 19)after flash chromatography (hexane/acetate 5:1.) M.p. 37.5
38.58C; 1H NMR (500 MHz, CDCl3): d ˆ 6.06 (m, 1H), 5.51 (q, J ˆ
1.58 Hz, 1H), 5.22 (d, J ˆ 5.99 Hz, 1H), 4.78 (brs, 1H), 4.45 (brs, 1H),
4.10 (t, J ˆ 6.78 Hz, 2H), 4.09 (t, J ˆ 6.78 Hz, 2H), 4.01 (t, J ˆ 6.78 Hz, 2H),
3.10 (t, J ˆ 7.25 Hz, 2H), 2.37 (m, 2H), 2.11 (m, 1H), 1.90 (m, 4H), 1.54
1.67 (m, 6H), 1.44 (m, 2H), 1.18 1.34 (m, 38H), 0.84 (m, 6H); 13C NMR
(125 MHz, CDCl3): d ˆ 173.3, 173.2, 167.5, 157.6, 136.5, 125.1, 65.6, 64.7,
52.5, 40.6, 31.9, 31.5, 30.4, 30.0, 29.6, 29.5, 29.4, 29.3, 29.2, 29.1, 28.5(3), 28.1,
26.5, 25.9, 25.8, 22.6, 22.5, 18.25, 14.0, 13.9; HRMS (FAB)calcd for
‡
25.8, 22.6, 14.1; HRMS (FAB)calcd for C 24H46NO6 [M ‡H]: 444.3325;
‡
C39H73N2O7 [M ‡H]: 681.5418; found: 681.5420.
found: 444.3326.
1,24-Bis[2-(methacryloyloxy)ethyl] 3,22-ditetradecyl (3S,22S)-5,20-dioxo-
4,6,19,21-tetraazatetracosane-1,3,22,24-tetracarboxylate (7): The product
was obtained as a white solid (90% from 18)after flash chromatography
(hexane/dichloromethane/acetone 6:3:1). M.p. 86.0 87.08C; 1H NMR
(500 MHz, CDCl3): d ˆ 6.11 (brs, 2H), 5.58 (brs, 2H), 5.05 (d, J ˆ
7.88 Hz, 2H), 4.61 (s, 2H), 4.49 (m, 2H), 4.26 4.36 (m, 8H), 4.09 (t, J ˆ
6.62 Hz, 4H), 3.12 (m, 4H), 2.43 (m, 4H), 2.15 (m, 2H), 1.93 (m, 8H), 1.61
(m, 4H), 1.46 (m, 4H), 1.20 1.34 (m, 60H), 0.86 (t, J ˆ 6.94 Hz, 6H);
13C NMR (125 MHz, CDCl3): d ˆ 173.3, 172.7, 157.8, 135.8, 126.0, 65.5, 62.3,
62.2, 52.3, 40.4, 31.8, 30.2, 30.1, 29.6,29.5, 29.5, 29.4, 29.3, 29.2, 29.15, 28.4,
28.0, 26.8, 25.7, 22.6, 18.1, 14.0; HRMS (FAB)calcd for C 64H115N4O14
Hydroxynonyl methacrylate was synthesized from the 1,9-nonane diol with
methacryloyl chloride, and was purified by flash column chromatography.
1H NMR (500 MHz, CDCl3): d ˆ 6.07 (s, 1H), 5.52 (m, 1H), 4.11 (t, J ˆ
6.78 Hz, 2H), 3.62 (t, J ˆ 6.78 Hz, 2H), 1.92 (s, 3H), 1.64 (m, 2H), 1.54 (m,
2H), 1.28 1.38 (m, 10H); 13C NMR (125 MHz, CDCl3): d ˆ 167.5, 136.5,
125, 1, 64.7, 62.9, 29.4, 29.2, 29.1, 28.5, 25.9, 25.6, 18.2.
5-[2-(Methacryloyloxy)ethyl] 1-tetradecyl (2S)-2-[(tert-butoxycarbonyl)-
amino]pentanedioate (18): Compound 17 (0.88 g, 2.0 mmol), hydroxyethyl
methacrylate (0.30 g, 2.3 mmol), and DMAP (0.02 g, 0.16 mmol) were
dissolved in dry dichloromethane (20 mL). The mixture was cooled to 08C
in an ice bath, and then EDCI (0.48 g, 2.5 mmol)was added. The mixture
was stirred in the ice bath, protected from light and moisture, for 6 h. The
work up was the same as before. Purification by chromatography (hexane/
‡
[M ‡H]: 1163.8410; found: 1163.8411.
1,24-Bis[9-(methacryloyloxy)nonyl] 3,22-ditetradecyl (3S,22S)-5,20-dioxo-
4,6,19,21-tetraazatetracosane-1,3,22,24-tetracarboxylate (8): The product
was obtained as a white solid (94% from 19). M.p. 88.0 89.08C; 1H NMR
(500 MHz, CDCl3): d ˆ 6.06 (m, 2H), 5.51 (m, 2H), 5.21 (m, 2H), 4.77 (m,
2H), 4.45 (m, 2H), 4.09 (m, 8H), 4.01 (t, J ˆ 6.78 Hz, 4H), 3.10(q, J ˆ
6.62 Hz, 4H), 2.39 (m, 4H), 2.11 (m, 2H), 1.91 (m, 8H), 1.54 1.68 (m, 8H),
1.44 (m, 4H), 1.20 1.34 (m, 2s, 48H), 0.85 (t, J ˆ 6.94 Hz, 6H); 13C NMR
(125 MHz, CDCl3): d ˆ 173.3, 173.2, 167.5, 157.6, 136.5, 125.1, 65.6, 64.7,
52.5, 40.5, 31.9, 30.4, 30.1, 29.6, 29.5, 29.5, 29.3, 29.2, 29.2, 29.1, 28.1, 26.8,
1
acetate 6:1)gave a white solid (1.05 g, 95%). M.p.36.0 36.5 8C; H NMR
(400 MHz, CDCl3): d ˆ 6.06 (s, 1H), 5.53 (m, 1H), 5.13 (d, J ˆ 8.08 Hz, 1H),
4.22 4.32 (m, 5H), 4.06 (t, J ˆ 6.82 Hz, 2H), 2.36 (m, 2H), 2.14 (m, 2H),
1.88 (m, 4H), 1.57 (m, 2H), 1.37 (s, 9H), 1.19 (s, 22H), 0.81 (t, J ˆ 7.07 Hz,
3H); 13C NMR (100 MHz, CDCl3): d ˆ 172.4, 172.1, 166.9, 155.2, 135.7,
126.0, 79.8, 65.6, 62.2, 52.7, 31.8, 30.0, 29.5, 29.4, 29.4, 29.2, 29.1, 28.4, 28.1,
‡
27.6, 25.7, 22.6, 18.1, 14.0; HRMS (FAB)calcd for C 25H46NO6 [M ‡H À
Boc]: 456.3325; found: 456.3325.
‡
25.9, 25.8, 22.6, 18.3, 14.1; HRMS (FAB)calcd for C 78H143N4O14 [M ‡H]:
5-[9-(Methacryloyloxy)nonyl] 1-tetradecyl (2S)-2-[(tert-butoxycarbonyl)-
amino]pentanedioate (19): The product was obtained as white crystals
(97% from 17)after flash chromatography (hexane/acetate 7:1.) M.p.
39.0 40.08C; 1H NMR (500 MHz, CDCl3): d ˆ 6.04 (m, 1H), 5.49 (m, 1H),
5.10 (d, J ˆ 8.20 Hz, 1H), 4.25 (m, 1H), 4.08 (t, J ˆ 6.63 Hz, 2H), 4.07 (t, J ˆ
6.62 Hz, 2H), 4.01 (t, J ˆ 6.78 Hz, 2H), 2.34 (m, 2H), 2.11 (m, 1H), 1.89 (m,
4H), 1.50 1.65 (m, 6H), 1.38 (s, 9H), 1.26 (s, 10H), 1.20 (s, 22H), 0.82 (t,
J ˆ 6.94 Hz, 3H); 13C NMR (125 MHz, CDCl3): d ˆ 172.7, 172.2, 167.4,
155.3, 136.5, 125.0, 79.7, 65.6, 64.7, 52.9, 31.8, 30.3, 29.6, 29.5, 29.5, 29.4, 29.3,
29.1, 29.1, 28.5, 28.4, 28.2, 27.8, 25.9, 25.8, 25.7, 22.6, 18.2, 14.0; HRMS
1360.0601; found: 1360.0601.
Bis[9-(methacryloyloxy)nonyl]
(2S)-2-[(tert-butoxycarbonyl)amino]bu-
tanedioate (23): 1H NMR (500 MHz, CDCl3): d ˆ 6.04 (m, 2H), 5.49 (m,
2H), 5.38 (d, J ˆ 8.51 Hz, 1H), 4.49 (m, 1H), 4.08 (t, J ˆ 6.62 Hz, 4H), 4.02
(m, 2H), 2.93 (dd, J ˆ 17.02, 4.41 Hz, 1H), 2.75 (dd, J ˆ 16.71, 4.73 Hz, 1H),
1.89 (m, 6H), 1.61 (m, 2H), 1.56 (m, 2H), 1.39 (s, 9H), 1.25 (m, 20H);
13C NMR (125 MHz, CDCl3): d ˆ 171.0, 170.9, 167.4, 155.3, 136.5, 125.0,
79.9, 65.7, 65.0, 64.6, 50.0, 36.7, 29.3, 29.1, 29.0, 29.0, 28.5, 28.2, 25.9, 25.7,
‡
18.2; HRMS (FAB)calcd for C 30H52NO8 [M ‡H À Boc]: 554.3693; found:
554.3695.
‡
(FAB)calcd for C 32H60NO6 [M ‡H À Boc]: 554.4421; found: 554.4420.
Tetrakis[9-(methacryloyloxy)nonyl] (2S,21S)-4,19-dioxo-3,5,18,20-tetra-
azadocosane-1,2,21,22-tetracarboxylate (9): The product was obtained as
a colorless solid (90% from 23). M.p.56.0 57.08C; 1H NMR (500 MHz,
CDCl3): d ˆ 6.03 (m, 4H), 5.58 (d, J ˆ 8.12 Hz, 2H), 5.48 (q, J ˆ 1.58 Hz,
4H), 5.02 (t, J ˆ 5.20 Hz, 2H), 4.70 (m, 2H), 4.07 (t, J ˆ 6.62 Hz, 8H), 4.04
(m, 4H), 3.97 (t, J ˆ 6.80 Hz, 4H), 3.08 (q, J ˆ 6.50 Hz, 4H), 2.77 (dd, J ˆ
16.71, 4.73 Hz, 2H), 2.91 (dd, J ˆ 16.71, 5.04 Hz, 2H), 1.87 (m, 12H), 1.60
(m, 8H), 1.53 (m, 8H), 1.43 (m, 4H), 1.15 1.30 (m, 56H); 13C NMR
(125 MHz, CDCl3): d ˆ 172.0, 171.3, 167.4, 157.5, 136.4, 125.0, 65.5, 64.8,
64.6, 49.4, 40.4, 37.1, 30.0, 29.3, 29.2, 29.2, 29.0, 29.0, 28.5, 28.4, 28.3, 26.8,
5-[2-(Methacryloyloxy)ethyl] 1-tetradecyl (2S)-2-aminopentanedioate
(20): 1H NMR (500 MHz, CDCl3): d ˆ 6.06 (m, 1H), 5.51 (m, 1H), 4.14
(t, J ˆ 6.78 Hz, 2H), 4.10 (t, J ˆ 6.78 Hz, 2H), 4.02 (td, J ˆ 2.21, 6.78 Hz,
2H), 2.54 (t, J ˆ 6.94 Hz, 2H), 2.23 (m, 2H), 1.9 (s, 3H), 1.54 1.66 (m, 6H),
1.20 1.40 (m, 32H), 0.84 (t, J ˆ 6.94 Hz, 3H); 13C NMR (125 MHz,
CDCl3): d ˆ 173.1, 169.1, 167.7, 136.4, 125.2, 67.2, 65.5, 64.8, 52.5, 31.9, 29.8,
29.6, 29.6, 29.5, 29.4, 29.3, 29.3, 29.1, 29.1, 28.5, 28.3, 28.2, 25.9, 25.7, 25.6,
25.1, 22.6, 18.2, 14.0.
5-[9-(Methacryloyloxy)nonyl] 1-tetradecyl (2S)-2-aminopentanedioate
(21): 1H NMR (500 MHz, CDCl3): d ˆ 6.11 (s, 1H), 5.60 (s, 1H), 4.28
4.32 (m, 4H), 4.14 4.24 (m, 3H), 2.62 (m, 2H), 2.27 (m, 2H), 1.9 (s, 3H),
‡
25.8, 25.7, 25.6, 18.2; HRMS (FAB)calcd for C 74H127N4O18 [M ‡H]:
1359.9145; found: 1359.9151.
1960
¹ WILEY-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002
0947-6539/02/0808-1960 $ 20.00+.50/0
Chem. Eur. J. 2002, 8, No. 8

Polymerizable Organogelators
1954 1961
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Acknowledgements
This work was supported by the National Science Foundation and the
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Received: November 6, 2001 [F3663]
Chem. Eur. J. 2002, 8, No. 8
¹ WILEY-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002
0947-6539/02/0808-1961 $ 20.00+.50/0
1961