The synthesis of calix[4]crown based dendrimer

Article abstract of DOI:10.1016/j.tet.2004.11.043

A second generation of dendrimer with calixcrown as repeat unit was first synthesized. Its structure and conformation was determined by ¹H NMR and MALDI-TOF mass spectra.

Full text of DOI:10.1016/j.tet.2004.11.043

Tetrahedron 61 (2005) 897–902
The synthesis of calix[4]crown based dendrimer
*
Jian-Hua Bu, Qi-Yu Zheng, Chuan-Feng Chen and Zhi-Tang Huang
*
Laboratory of Chemical Biology, Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China
Received 28 July 2004; revised 4 November 2004; accepted 5 November 2004
Available online 8 December 2004
Abstract—A second generation of dendrimer with calixcrown as repeat unit was first synthesized. Its structure and conformation was
determined by H NMR and MALDI-TOF mass spectra.
q 2004 Elsevier Ltd. All rights reserved.
1
1. Introduction
Therefore, the research on this field is still largely
unexplored.
Dendrimers are macromolecules that radiate out from a
central core and have at least one branch at each repeat unit.
A typical of dendrimer contains three different regions:
core, branches, and periphery, and all of them can be
modified to exhibit certain function. Due to their unique
physical property and structure, such as, highly branched
structure, monodispersed molecular weight, globular and
symmetrical conformation, and high density of peripheral
functionalities, the researches based on them has expanded
exponentially in recent years.1
If the 1,3-calix[4]crown, an excellent ionphore could be
introduced to the dendrimers as repeat unit, a ‘multi-metal
recognition central’ dendrimer will be obtained. It may be
helpful to mimic the ion channel, a very important
biological structure. Here, we report the synthesis and
conformation of a second generation of dendrimer with 1,3-
calix-[4]-benzocrown-6 as repeat unit.
2. Results and discussion
2.1. Synthesis of monomer
There are two basic approaches for the stepwise synthesis of
dendrimers: The divergent approach2 and convergent
approach.3 In the divergent approach, the synthetic
sequence is from the core to periphery; while the convergent
approach is from the periphery to core.
In order to obtain a dendrimer with calixcrown as repeat
unit, we needed to synthesize a calixcrown monomer with
three functional groups in two different types. For a 1,3-
calix[4]crown, the positions where functional group could
be introduced included the four upper rim carbon atoms and
two low rim oxygen atoms. If the monomer was a
calixazacrown or calixbenzocrown, the nitrogen atom or
the phenyl unit could be another position. However, the
upper rim was not a good choice for introducing functional
groups, because of much harsh synthetic conditions and low
yield. At the same time, a rather large group at the upper rim
facing the ether crown ring would hinder the ether crown to
recognize the guest.7 Therefore, a calixbenzocrown 4
(Scheme 1), which had two ester groups at lower rim and
one aldehyde group at the phenyl unit, was chosen as the
monomer.
Calixarene are well-defined macrocyclic molecules, which
are readily available in large quantities and easily modified
by chemical reaction to bind various kinds of anions,
cations, and neutral molecules.4 It is an original idea to
integrate calixarenes and dendrimers as well as their unique
properties to form new structural host, and there have
several examples about dendrimers with calixarene as core.5
However, it may be due to the serious steric problem caused
by the large sized calixarenes, there are only a few examples
on dendrimers with calixarenes as branched units reported,6
and in most of these works, only the first-generation
dendrimers was obtained, except one example of second-
generation dendrimer with seven calixarene moieties.6e
There were several advantages for choosing 4 as the
monomer: (1) it was easy to synthesize; (2) the ester groups
and aldehyde group located at each end of the molecule,
which could reduce the steric repulsion to a very low
Keywords: Calix[4]crown; Dendrimer; Convergent approach.
* Corresponding authors. Tel.: C86 10 62544082; fax: C86 10 62564723;
e-mail: huangzt@public.bta.net.cn
0040–4020/$ - see front matter q 2004 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2004.11.043

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J.-H. Bu et al. / Tetrahedron 61 (2005) 897–902
Scheme 1.
degree; (3) because the ester group and aldehyde group did
not react each other under common conditions, we did not
need to use protection and deprotection strategy during the
synthesis of dendrimer. On the other hand, they were easy to
be converted to carboxyl group and benzyl alcohol group,
and then linked together under mild condition with high
yield; (4) the three functional groups had little effect on the
recognition ability of the ether crown ring.
other, we needed to activate them respectively before
preparing 1st generation of dendrimer.
Hydrolysis of 4 using 10% tetramethylammonium
hydroxide aqueous solution under room temperature
afforded the diacid 5, in nearly quantitative yield.
Reduction of 4 with NaBH4 under ice bath, the aldehyde
group could be converted to benzyl alcohol group in 60%
yield. The relatively low yield was contributed to that the
ester group at the low rim could be reduced to ethylene
glycol under similar condition. To prevent this side reaction,
the quantity of NaBH4 was not allowed to exceed 2 equiv of
the compound 4, the reaction temperature must be low, and
reaction time must be short. However, under this condition,
the reaction could not acquire completion. The exceeding
reactant could be retrieved by chromatography.
Monomer 4 could be obtained using the method developed
by Reinhoudt et al.,8 so we needed to synthesize the
corresponding diethylene glycol ditosylate 3, first. This
compound could be prepared from 3,4-dihydroxybenzalde-
hyde through two steps in a fairly good yield (Scheme 1). In
the presence of Cs2CO3, 3 reacted with 25,27-diethoxycar-
bonylmethoxycalix[4]arene (1) in MeCN under argon
affording the monomer 4 in 55% yield. The signal at
37.6 ppm in its 13C NMR spectrum indicated it fixed in 1,3-
alternative conformation (Schemes 2–4).9
With the two blocks in hand, the 1st generation of dendrimer
could be obtained by the condensation of 1 equiv of 5 and
2 equiv of 6 under the treatment of DCC/DMAP in high
yields (91%).
2.2. The 1st generation of dendrimer
Because the ester and aldehyde groups could not react each
Scheme 2.
Scheme 3.

J.-H. Bu et al. / Tetrahedron 61 (2005) 897–902
899
Scheme 4.
The two carbon signals at 37.7 and 37.5 in its 13C NMR
spectra indicated that all of the calix[4]crown were fixed in
1,3-alteralternative conformation.9
The 2nd generation of dendrimer 9 can be obtained by the
condensation of 2 equiv of 8 and 1 equiv of 5 in high yields
using the same method for the preparation of 1st generation
dendrimer (Scheme 6).
2.3. The 2nd generation of dendrimer
In conclusion, we have synthesized the first 2nd generation
of dendrimer based on calixcrown. Its structure and
There are two ways to prepare the 2nd generation of
dendrimer: the divergent approach and the convergent
approach.
1
conformation were confirmed by H NMR and MALDI-
TOF mass spectra. The recognition properties of the
dendrimers are under investigation.
If the convergent approach were chosen, we would face the
same problem of over reduction we had encountered in the
synthesis of 6, and the much larger 1st generation dendrimer
would cause more serious steric problem during the
synthesis of 2nd generation of dendrimer. But if the
divergent way were chosen, we would face much more
difficult problems: (1) because there were six ester groups, it
would be very difficult to selectively saponify the four
peripheric ones; (2) even the saponification could acquire
success, the total yield would be low since the next
condensation step needed the relative low-yield compound
6 as reactant; (3) the divergent way required four reaction
positions during the process of the condensation, but the
convergent way only need two.
Due to the inherent shortcomings of the divergent way, we
chose convergent way for the preparation of the 2nd
generation of dendrimer.
First, we intended to obtain the corresponding benzyl
alcohol compound 8 from 7 by the same method in the
synthesis of compound 6, but failed. The reason may be that
both 7 and 8 were hardly dissolved in EtOH. So we used
THF instead of EtOH as solvent, and the 8 was obtained in a
fairly good yield (Scheme 5).
Scheme 5.

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J.-H. Bu et al. / Tetrahedron 61 (2005) 897–902
Scheme 6.
1
3. Experimental
IR (KBr): 3378, 2755, 1682, 1586 cmK1; H NMR: d 9.84
(s, 1H, ArCHO), 7.47–7.41 (m, 2H, ArH), 6.98 (d, 1H, JZ
8.1 Hz, ArH), 4.26–4.21 (m, 4H, Ar–OCH2CH2O–), 3.97–
3.92 (m, 4H, Ar–OCH2CH2O–), 3.77–3.75 (m, 4H,
–OCH2CH2OH), 3.70–3.68 (m, 4H, –OCH2CH2OH), 3.52
(s, 2H, CH2OH); 13C NMR: d 190.8 (ArCHO), 153.8, 148.8,
130.2, 126.9, 111.7, 110.6 (ArC), 72.8, 72.7, 69.0, 68.8,
68.5, 68.4, 61.6 (–OCH2CH2O–); MS (EI): 314 (27), 164
(32), 89 (23), 45 (100). Anal. Calcd for C15H22O7$0.25H2O
C, 56.51; H, 7.11. Found, C, 56.66; H, 7.06.
3.1. General
Melting points were determined on an electrothermal
melting point apparatus and uncorrected. 1H and 13C
NMR spectra were obtained at 300 and 75 MHz (CDCl3,
TMS as internal standard) respectively on a Bruker
DMX300 NMR. MALDI-TOF MS was recorded on a
Bruker BIFLEXIII mass spectrometer with CCA (2-cyano-
40-hydroxycinnamic acid) as the matrix. Elemental analyses
were performed by the Analytical Laboratory of the
Institute. IR Spectra were recorded on a JASCO 480
spectrometer. Preparative column chromatography was
performed with silica gel (200–300 mesh). Petroleum
ether for column chromatography refers to that of
3.1.2. Compound 3. Compound 2 (950 mg, 3 mmol) was
dissolved in THF (15 mL), and a solution of NaOH
(360 mg, 9 mmol) in H2O (10 mL) was added. The mixture
was cooled to 0 8C, then a solution of p-toluenesulfonyl
chloride (1.2 g, 6.3 mmol) in THF (15 mL) was added
dropwise during a period of 2 h. The mixture was stirred
under ice bath for another 2 h, and then 1 mol LK1 of HCl
was added until the pH value of the solution reach to 3. THF
was removed under reduced pressure, and the residue was
extracted with CH2Cl2 (30 mL!2). The combined organic
phase was dried with Na2SO4. Then purified on silica
column, using ether/acetoneZ3/1 as eluant to afford a
colorless oil: yield 75%; IR (KBr): 3559, 1686, 1593, 1509,
1437, 1354, 1270 cmK1; 1H NMR: d 9.84 (s, 1H, ArCHO),
7.78 (d, 4H, JZ8.1 Hz, ArH), 7.46 (d, 1H, JZ8.2 Hz, ArH),
7.38 (s, 1H, ArH), 7.30 (d, 4H, JZ8.1 Hz, ArH), 6.97 (d,
1H, JZ8.2 Hz, ArH), 4.19–4.10 (m, 8H, Ar–OCH2CH2O–),
3.86–3.75 (m, 8H, –OCH2CH2O–), 2.41 (s, 6H, ArCH3);
13C NMR: d 190.8 (ArCHO), 154.1, 149.0, 144.8, 132.9,
130.3, 129.8, 127.9, 126.8, 112.4, 111.5 (ArC), 69.6, 69.5,
˚
60–90 8C boiling range. MeCN was dried over 4 A
molecular sieve. THF was freshly distilled over Na before
used. All other chemicals were reagent grade and were used
without further purification. Compound 1 was prepared
according to literature procedures.10
3.1.1. Compound 2. 3,4-Dihydroxy-benzaldehyde (690 mg,
5 mmol) was dissolved in MeCN (50 mL), then diethylene
glycol mono-tosylate (2.6 g, 10 mmol) and potassium
carbonate (1.38 g, 10 mmol) were added. The mixture was
refluxed under argon for 36 h. After cooling to room
temperature, the mixture was filtered, and the solvent was
removed under reduced pressure. The crude product was
purified on a silica column using petroleum ether/acetoneZ
2/1. The product was obtained as colorless oil: yield 86%;

J.-H. Bu et al. / Tetrahedron 61 (2005) 897–902
901
69.3, 69.0, 68.9, 68.6 (–OCH2CH2O–), 21.6 (ArCH3); MS
(MALDI-TOF): 622.9 (MCHC), 644.9 (MCNaC), 660.8
(MCKC). Anal. Calcd for: C29H34O11S2 C, 55.94; H, 5.50.
Found, C, 55.83; H 5.72.
was obtained as white solid by chromatography (silica
column, petroleum ether/acetoneZ5/1): yield: 63%; mp
57–59 8C; IR (KBr): 3441, 1753 cmK1; 1H NMR: d 7.13 (d,
4H, JZ7.5 Hz, ArH), 7.09 (d, 4H, JZ7.5 Hz, ArH), 7.04 (s,
1H, ArH), 6.97 (s, 2H, ArH), 6.79 (t, 2H, JZ7.5 Hz, ArH),
6.70 (t, 2H, JZ7.5 Hz, ArH), 4.65 (s, 2H, ArCH2OH), 4.17–
4.12 (m, 4H, Ar–O–CH2CH2–), 4.08 (q, 4H, JZ7.2 Hz,
CH3CH2–), 4.04 (d, 4H, JZ15.9 Hz, ArCH2Ar), 3.80–3.74
(m, 8H, ArCH2Ar, Ar–O–CH2CH2–), 3.70 (t, 4H, JZ
6.0 Hz, Ar–O–CH2CH2–), 3.50 (t, 4H, JZ6.0 Hz, Ar–O–
CH2CH2–), 3.35 (s, 4H, –OCH2–CO–), 1.21 (t, 3H, JZ
7.2 Hz, CH3CH2–); 13C NMR: d 170.1 (–OCO–), 157.0,
155.3, 149.4, 148.6, 134.9, 134.7, 133.8, 130.6, 130.5,
123.1, 122.7, 120.5, 115.6, 114.3 (ArC), 70.6, 70.5, 70.3,
69.9, 69.7, 68.4, 65.2 (–OCH2CH2O–, –OCH2CO–, ArCH2-
OH), 60.3 (–OCH2CH3), 37.7 (ArCH2Ar), 14.1
(–OCH2CH3); MS (MALDI-TOF): 899.4 (MCNaC),
915.4 (MCKC). Anal. Calcd for: C51H56O13 C, 69.85; H,
6.44. Found, C, 69.59; H, 6.50.
3.1.3. Compound 4. 25,27-Diethoxycarbonylmethoxy-
calix[4]arene (1) (596 mg, 1 mmol) was dissolved in
MeCN (250 mL), and 3 (653 mg, 1.05 mmol), cesium
carbonate (652 mg, 2 mmol) was added under argon. The
mixture was refluxed for 30 h, and then cooled to room
temperature. The solvent was removed under reduced
pressure, and the residue was dissolved in CH2Cl2
(30 mL) and 1 mol LK1 HCl (30 mL). The organic layer
was separated, and washed with water (30 mL!2), dried
with Na2SO4. Then the crude product was purified on silica
column, using ether/acetoneZ5/1 as eluant to afford a white
solid: yield 55%; mp 65–67 8C; IR (KBr): 2730, 1752 cmK1
;
1H NMR: d 9.88 (s, 1H, ArCHO), 7.53–7.51 (m, 2H, ArH),
7.15–7.09 (m, 9H, ArH), 6.80 (t, 2H, JZ7.5 Hz, ArH), 6.68
(t, 2H, JZ7.5 Hz, ArH), 4.26–4.21 (m, 4H, Ar–O–
CH2CH2–), 4.09 (q, 4H, JZ7.2 Hz, CH3CH2O–), 4.05 (d,
4H, JZ14.1 Hz, ArCH2Ar), 3.87–3.80 (m, 6H, Ar–OCH2-
CH2O–, ArCH2Ar), 3.74–3.67 (m, 6H, –OCH2CH2O–),
3.60–3.45 (m, 4H, –OCH2CH2O–), 3.40 (s, 4H, –OCH2–
CO–), 1.22 (t, 6H, JZ7.2 Hz, CH3CH2–); 13C NMR: d
190.8 (ArCHO), 170.0 (–OCO–), 156.8, 155.3, 154.4,
149.2, 134.5, 133.9, 133.8, 130.6, 130.5, 130.4, 127.0,
123.1, 122.5, 112.9, 112.4 (ArC), 70.4, 70.3, 70.2, 70.0,
69.9, 69.4, 69.3, 68.4, 60.3 (–OCH2CH2O–, –OCH2CO–,
–CH2CH3), 37.6 (ArCH2Ar), 14.1 (–CH2CH3); MS
(MALDI-TOF): 897.5 (MCNaC), 913.5 (MCKC). Anal.
Calcd for: C51H54O13 C, 70.01; H, 6.22. Found, C, 69.61; H,
6.19.
3.1.6. Compound 7. Compound 5 (82 mg, 0.1 mmol) and 6
(175 mg, 0.2 mmol) was dissolved in 3 mL of dried CH2Cl2,
then DCC (42 mg, 0.2 mmol) and DMAP (5 mg,
0.04 mmol) was added under argon. After the mixture was
stirred for 12 h, DCU was filtered. The organic layer was
washed successively with 1 mol LK1 HCl (5 mL!2) and
water (10 mL!2), dried with Na2SO4. The crude product
was purified on a silica column, using petroleum ether/
acetoneZ3/1 as eluant to afford white solid: yield 91%; mp
102–104 8C; IR (KBr): 1755, 1734, 1687 cmK1; 1H NMR: d
9.88 (s, 1H, ArCHO), 7.51 (s, 2H, ArH), 7.12 (d, 8H, JZ
7.5 Hz, ArH), 7.08–7.06 (m, 17H, ArH), 6.99 (s, 2H, ArH),
6.96 (s, 4H, ArH), 6.79 (t, 4H, JZ7.5 Hz, ArH), 6.71–6.61
(m, 8H, ArH), 5.02 (s, 4H, ArCH2–O–CO–), 4.23–4.03 (m,
24H, Ar–O–CH2CH2–, ArCH2Ar, CH3CH2–), 3.97 (AB,
JZ16.6 Hz, 12H, ArCH2Ar) 3.84–3.61 (m, 32H, Ar–O–
CH2CH2–, Ar–O–CH2CH2–), 3.59–3.47 (m, 12H, Ar–O–
CH2CH2–), 3.40 (s, 4H, Ar–O–CH2CO–), 3.35 (s, 8H, Ar–
O–CH2CO–), 1.21 (t, 12H, JZ7.2 Hz, CH3CH2–); 13C
NMR: d 190.8 (ArCHO), 170.0, 169.8 (–OCO–), 156.9,
155.3, 154.4, 149.4, 149.3, 149.1, 134.6, 134.5, 133.8,
130.7, 130.5, 130.4, 129.3, 123.1, 122.6, 122.5, 116.2,
115.2, 112.9, 112.4 (ArC), 70.5, 70.2, 70.1, 69.9, 69.8, 69.7,
69.4, 69.3, 68.5, 68.3 (–OCH2CH2O–, –OCH2CO–), 60.3
(–OCH2CH3), 37.7, 37.5 (ArCH2Ar), 14.1 (–OCH2CH3);
MS: (MALDI-TOF): 2557.1 (MCNaC). Anal. Calcd for:
C149H154O37 C, 70.55; H, 6.12. Found, C, 70.67; H, 6.64.
3.1.4. Compound 5. Compound 4 (175 mg, 0.2 mmol) was
dissolved in THF (5 mL), and then 1 mL of 10%
tetramethylammonium hydroxide was added. The mixture
was stirred under argon for 4 h, then acidified with
1 mol LK1 HCl until white precipitation was occurred,
filtered to afford white solid, yield 95%; mp 211–213 8C; IR
1
(KBr): 3420, 1778, 1758, 1732 cmK1; H NMR: d 9.89 (s,
1H, ArCHO), 7.56–7.50 (m, 2H, ArH), 7.13–7.04 (m, 9H,
ArH), 6.90 (t, 2H, JZ7.5 Hz, ArH), 6.80 (t, 2H, JZ7.5 Hz,
ArH), 4.18 (t, 2H, JZ4.8 Hz, Ar–O–CH2CH2–), 4.14 (t, 2H,
JZ4.8 Hz, Ar–O–CH2CH2–), 4.11 (s, 4H, –OCH2–CO–),
3.94 and 3.80 (AB, 8H, JZ16.2 Hz, ArCH2Ar), 3.70 (t, 2H,
JZ4.8 Hz, Ar–O–CH2CH2–), 3.65–3.57 (m, 6H, Ar–O–
CH2CH2–), 3.48 (t, 4H, JZ5.7 Hz, Ar–O–CH2CH2–); 13C
NMR: d 190.9 (ArCHO), 168.4 (–OCO–), 156.1, 154.5,
153.4, 149.3, 133.7, 133.6, 130.7, 130.2, 130.1, 129.6,
127.1, 124.4, 113.2, 112.8 (ArC), 70.4, 70.2, 70.1, 70.0,
69.9, 69.8, 67.1 (–OCH2CH2O–, –OCH2CO–), 37.5
(ArCH2Ar); MS (MALDI-TOF): 840.8 (MCNaC), 856.7
(MCKC). Anal. Calcd for: C47H46O13$H2O C, 67.45; H,
5.78. Found, C, 67.61; H, 5.56.
3.1.7. Compound 8. Compound 7 (126 mg, 0.05 mmol) was
suspended in 5 mL of THF under ice bath, and then NaBH4
(4 mg, 0.10 mmol) was added. After stirred for 10 min,
5 mL of water was added. The solution was extracted with
CH2Cl2 (10 mL!2), and the combined organic layer was
washed successively with 1 mol LK1 HCl (10 mL!2), then
water (10 mL!2), dried with Na2SO4. The pure product
was obtained as white solid by chromatography (silica
column, petroleum ether/acetoneZ5/1): yield: 60%; mp
105–107 8C; IR (KBr): 3441, 1753, 1734 cmK1; 1H NMR: d
7.12 (d, 8H, JZ7.5 Hz, ArH), 7.07 (d, 16H, JZ7.5 Hz,
ArH), 7.04–6.92 (m, 9H, ArH) 6.79 (t, 4H, JZ7.5 Hz, ArH),
6.69 (t, 6H, JZ7.5 Hz, ArH), 6.30 (t, 2H, JZ7.5 Hz, ArH),
5.01 (s, 4H, Ar–O–CH2CO–), 4.65 (s, 2H Ar–O–CH2CO–),
4.20–4.12 (m, 12H, Ar–CH2–Ar, Ar–O–CH2–), 4.08 (q, 8H,
3.1.5. Compound 6. Compound 4 (175 mg, 0.2 mmol) was
suspended in EtOH (5 mL) under ice bath, and then NaBH4
(17 mg, 0.45 mmol) was added. After stirred for 10 min,
5 mL of water was added. The solution was extracted with
CH2Cl2 (10 mL!2), and the combined organic layer was
washed successively with 1 mol LK1 HCl (10 mL!2), and
water (10 mL!2), dried with Na2SO4. The pure product

902
J.-H. Bu et al. / Tetrahedron 61 (2005) 897–902
Angew. Chem. Int. Ed. 1999, 38, 884–905. (d) Matthews,
O. A.; Shipway, A. N.; Stoddart, J. F. Prog. Polym. Sci. 1998,
23, 1–56. (e) Tomalia, D. A. Adv. Mater. 1994, 6, 529–539. (f)
Zeng, F.; Zimmerman, S. C. Chem. Rev. 1997, 97, 1681–1712.
JZ7.2 Hz, CH3CH2–), 4.09–4.05 (m, 4H, Ar–CH2–Ar),
3.98 (d, 8H, JZ15.2 Hz, Ar–CH2–Ar), 3.84–3.61 (m, 36H,
Ar–CH2–Ar, Ar–O–CH2CH2–, Ar–O–CH2CH2–), 3.59–
3.43 (m, 12H, Ar–O–CH2CH2–), 3.35 (s, 8H, Ar–
OCH2CO–), 3.33 (s, 4H, Ar–OCH2CO–), 1.21 (t, 12H,
JZ7.2 Hz, CH3CH2–); 13C NMR: d 170.1, 170.0 (–OCO–),
157.0, 155.3, 155.2, 149.4, 149.2, 148.6, 134.7, 134.6,
133.9, 133.8, 130.7, 130.6, 130.5, 129.4, 129.3, 123.2,
122.7, 116.2, 115.5, 115.3 (ArC), 70.5, 70.3, 70.0, 69.9,
68.4, 66.0, 65.2 (–OCH2CH2O–, –OCH2CO–, ArCH2OH),
60.3 (–OCH2CH3), 37.7 (ArCH2Ar), 14.1 (–OCH2CH3);
MS (MALDI-TOF): 2560.1 (MCNaC), 2576.1 (MCKC).
Anal. Calcd for: C149H156O37 C, 70.49; H, 6.19. Found, C,
70.69; H, 6.56.
¨
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3.1.8. Compound 9. Compound 5 (8 mg, 0.01 mmol) and 8
(51 mg, 0.02 mmol) was treated in the same way as
described in the synthesis of 7: yield: 88%; mp 115–
4. Gutsche, C. D. Calixarene Revisited. In Monographs in
Supramolecular Chemistry; Stoddart, J. F., Ed.; Royal Society
of Chemistry: London, 1998.
1
117 8C; IR (KBr): 1755, 1734 cmK1; H NMR: d 9.88 (s,
5. (a) Ferguson, G.; Gallagher, J. F.; McKervery, M. A.;
Madigan, E. J. Chem. Soc. Perkin Trans. 1 1996, 599–602.
(b) Nagasaki, T.; Tamagaki, S.; Ogino, K. Chem. Lett. 1997,
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1H, ArCHO), 7.52–7.50 (m, 2H, ArH), 7.13–7.06 (m, 56H,
ArH), 6.99–6.96 (m, 19H, ArH), 6.78 (t, JZ7.4 Hz, 10H,
ArH), 6.69–6.58 (m, 18H, ArH), 5.00 (s, 12H, Ar–CH2–O–),
4.30–3.69 (m, 152H, Ar–CH2–Ar, Ar–O–CH2–CH2–),
3.59–3.42 (m, 32H, 3.35 (s, 28H, ArO–CH2–CO–), 1.21
(t, JZ7.2 Hz, 24H, CH3CH2–); MS: (MALDI-TOF): 5879.1
(MCNaC). Anal. Calcd for: C345H354O85 C, 70.71; H, 6.09.
Found, C, 70.41; H, 6.51.
6. (a) Mogck, O.; Parzuchowski, P.; Nissinen, M.; Bohmer, V.;
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Z.-T. Tetrahedron 2002, 58, 3729–3736. (e) Szemes, F.;
Drewb, M. G. B.; Beer, P. D. Chem. Commun. 2002,
1228–1229.
Acknowledgements
We thank the National Natural Science Foundation of
China, the Major State Basic Research Development
Program of China (Grant No. G2000078100) and the
Chinese Academy of Sciences for financial support.
7. Casnati, A.; Pochini, A.; Ungaro, R.; Bocchi, C.; Ugozzoli, F.;
Egberink, R. J. M.; Struijk, H.; Lugtenberg, R.; de Jong, F.;
Reinhoudt, D. N. Chem. Eur. J. 1996, 2, 436–445.
8. Casnati, A.; Pochini, A.; Ungaro, R.; Ugozzoli, J. F.; Arnaud,
F.; Fanni, S.; Schwing, M.-J.; Egberink, R. J. M.; de Jong, F.;
Reinhoudt, D. N. J. Am. Chem. Soc. 1995, 117, 2767–2777.
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References and notes
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¨
Moorefield, C. N.; Vogtle, F. Dendrimers and Dendrons:
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Pochini, A.; Ungaro, R.; Harkema, S.; Reinhoudt, D. N. J. Org.
Chem. 1990, 55, 5639–5646.
Concepts, Syntheses, Applications, 2nd ed.; Wiley-VCH: New
York, 2001. (b) Bosman, A. W.; Janssen, H. M.; Meijer, E. W.
¨
Chem. Rev. 1999, 99, 1665–1688. (c) Fischer, M.; Vogtle, F.