Selective monofunctionalization of tri-urea-mono-acetamides of calix[4]arenes on the narrow rim

Article abstract of DOI:10.1055/s-2008-1032155

The synthesis of calix[4]arenes substituted at their wide rim by three 3-aryl-urea and one acetamide group and at their narrow rim by three alkyl ether groups and one ether group ending in a carboxy function is described. The reaction sequence ensures that these functional groups are attached to the same phenolic unit. Two key intermediates have been additionally characterized by X-ray crystal structure analysis. Georg Thieme Verlag Stuttgart.

Full text of DOI:10.1055/s-2008-1032155

754
PAPER
Selective Monofunctionalization of Tri-urea-mono-acetamides of
Calix[4]arenes on the Narrow Rim
M
onofunctionaliza
u
tion of
T
ri-
u
l
rea-mo
i
no-ac
e
y
tamides of
C
a
alix[4]arenes Rudzevich,*a Valentyn Rudzevich,a,1 Michael Bolte,b,2 Volker Böhmer*a
a
Abteilung Lehramt Chemie, Fachbereich Chemie, Pharmazie und Geowissenschaften, Johannes Gutenberg-Universität Mainz,
Duesbergweg 10-14, 55099 Mainz, Germany
Fax +49(6131)3925419; E-mail: rudzevic@mail.uni-mainz.de; E-mail: vboehmer@mail.uni-mainz.de
Fachbereich Chemie und Pharmazeutische Wissenschaften, Institut für Anorganische Chemie, Johann Wolfgang Goethe-Universität,
Max-von-Laue-Str. 7, 60438 Frankfurt/Main, Germany
b
Fax +49(69)79829239; E-mail: bolte@chemie.uni-frankfurt.de
Received 4 October 2007; revised 16 November 2007
Abstract: The synthesis of calix[4]arenes substituted at their wide
rim by three 3-aryl-urea and one acetamide group and at their nar-
row rim by three alkyl ether groups and one ether group ending in a
carboxy function is described. The reaction sequence ensures that
these functional groups are attached to the same phenolic unit. Two
key intermediates have been additionally characterized by X-ray
crystal structure analysis.
Key words: calixarenes, alkylations, carboxylic acids, self-assem-
bly, supramolecular chemistry
Tetra-urea calix[4]arenes of type 1 form hydrogen-bond-
ed, dimeric capsules (Figure 1, a) in apolar, aprotic sol-
vents.3 This dimerization can be used (and has been used)
to construct various linear polymers from building blocks
consisting of tetra-urea derivatives covalently connected
via their narrow4,5 rims. The construction of dendritic
structures can be achieved in a similar way, which howev-
er, requires several independent (self) complementary
motifs.6 Recently we succeeded in building up dendri-
mers,7 using the selective dimerization of tri-urea
triphenylmethanes8 for the core and the selective dimer-
ization of tetra-urea calix[4]arenes for the formation of the
shell.9
Figure 1 Dimeric capsule of tetra-urea calix[4]arenes 1 (a) and tet-
rameric assembly of tri-urea monoacetamide derivative 2 (b)
With this background we have tried to introduce a carbox-
ylic group12 as an additional functional group on the nar-
row rim in the phenolic ring bearing the acetamide
group.13 It is separated from the calixarene skeleton by a
short (C1) and a long (C10) alkyl chain in order to vary the
length of the spacer in the further dendrons. A synthetic
sequence is described and discussed here.
Tri-urea monoacetamide derivative 2 forms S4-symmetri-
cal tetrameric assemblies (Figure 1, b) in solution and in
the crystalline state.10 This tetramerization occurs inde-
pendently from the dimerization of tetra-urea calix[4]ar-
enes. Therefore, such tetramers would be ideal cores for
the construction of dendrimers. For this purpose 2 has to
be connected covalently to further calixarene derivatives
via the narrow rim and, thus, must be further functional-
ized. To obtain structurally uniform dendrimers, an addi-
tional function must be introduced selectively either at the
aromatic ring possessing an acetamide group or opposite
to it.11 Functionalization of one of the other phenolic units
leads to chiral calix[4]arenes and hence to a mixture of
diastereomeric dendritic assemblies. Statistical mono-
functionalization would be even worse.
The synthesis of 14a started with the mononitro-tripropyl-
calixarene 3, which was easily prepared by selective ipso-
nitration of the tripropyl ether of tert-butyl-calix[4]ar-
ene.14 Alkylation with ethyl bromoacetate afforded 4 in
79% yield (Scheme 1). In principle, its nitro group could
be easily reduced and then acetylated. However, the sub-
sequent ipso-nitration of the remaining tert-butylphenol
rings would lead to products (at least byproducts), in
which the position ortho to the N-acylamino group is also
substituted.15 Recently it was shown that the protection of
the amino groups by phthalimide allows ipso-nitration to
be restricted to the desired replacement of tert-butyl
groups.16 Thus compound 4 was reduced and monoamine
5 was condensed with phthalic acid anhydride [Zn(OAc)2,
pyridine] to give 8a in 73% yield.
SYNTHESIS 2008, No. 5, pp 0754–0762
x
x
.
x
x
.2
0
0
8
For the synthesis of 14b bearing the carboxylic function
on a longer alkyl chain the analogous reaction sequence is
Advanced online publication: 08.02.2008
DOI: 10.1055/s-2008-1032155; Art ID: T15607SS
© Georg Thieme Verlag Stuttgart · New York

PAPER
Monofunctionalization of Tri-urea-mono-acetamides of Calix[4]arenes
755
Scheme 1 Synthesis of the tri(tolyl)urea monoacetamides 14. Reagents and conditions: (i) Na2CO3, MeCN, reflux; (ii) Raney Ni, toluene–
EtOH; (iii) Zn(OAc)2, phthalic anhydride, pyridine, reflux; (iv) Raney Ni, toluene–THF; Ac2O, Et3N; (v) Br(CH2)10CO2Et, NaH, DMF; (vi)
THF–MeOH, NaOH–H2O, reflux; EtOH, H2SO4, reflux; (vii) HNO3, CH2Cl2–AcOH; (viii) HCl, toluene–EtOH, reflux; (ix) Ac2O, Et3N,
CHCl3; (x) 4-TolNCO, CH2Cl2; (xi) THF–DMF, NaOH–H2O (for 14a), THF–MeOH, NaOH–H2O (for 14b).
not possible. The direct alkylation of the deactivated 4-ni- The spectrum of 13a in CDCl3 shown in Figure 2 is very
trophenol ring in 3 with ethyl 11-bromoundecanoate similar to that of compound 2 described previously.10 This
failed due to the lower reactivity of the alkylating agent in confirms the formation of a tetramer with the same sym-
comparison to ethyl bromoacetate. Therefore, the mono- metry. In the aromatic region the expected 21 signals were
nitro derivative 3 was reduced and acetylated in situ to 6 observed, from which six ortho-coupled doublets corre-
(99%) (Scheme 1). The following alkylation was easy, spond to the aromatic protons of the tolyl residues. The
giving 7 in 93% yield. As discussed above, 7 cannot be di- eight meta-coupled doublets for the aromatic protons of
rectly nitrated to 11b. In the next two steps the acetamide calixarene rings were distinguished with the help of
group was therefore replaced by the phthalimide group.
COSY-gs. The remaining six singlets were attributed to
the NH protons of the urea and amide residues, while one
singlet is covered by the signal of the solvent. In the ali-
phatic part of the spectrum eight doublets for the methyl-
ene bridges, three singlets for the tolyl CH3 protons and
one signal for amide CH3 are found.
The ipso-nitration of compounds 8 gave trinitro mono-
phthalimide derivatives 9 in 89–95% yield. The phthalim-
ide group was readily cleaved with a threefold excess of
hydrochloric acid and the resulting amines 10 were acylat-
ed with acetic anhydride. The calixacetamides 11, in
which the ester group at the narrow rim and the acetamide 1H NMR (Figure 2) and COSY-gs NMR spectra con-
group at the wide rim are introduced at the same aromatic firmed the ability of the 13a and 13b to form a tetramer in
ring, were obtained in 76–98% yield. Finally, the reduc- spite of the ester group at the narrow rim.
tion of the remaining nitro groups (83–85% of 12), fol-
A single crystal of the mono-nitro calix[4]arene 4 was ob-
lowed by acylation with 4-tolyl isocyanate (65–86% of
tained by slow evaporation of an acetonitrile solution. The
13), and hydrolysis of the ester function afforded the tar-
compound crystallizes in the monoclinic space group
get compounds 14 (98%).
P21/n.17 The molecule adopts the flattened (pinched) cone
conformation (Figure 3). This is revealed clearly by the
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756
Y. Rudzevich et al.
PAPER
Figure 2 The 1H NMR spectrum of 13a in CDCl3 (400 MHz, 25 °C): (a) NH and aromatic signals: NH (green); ArH of tolyl groups (light
blue); ArH of calixarene skeleton (red); (b) aliphatic signals: ArCH2Ar (dark blue), OCH2CH3 (orange); ArCH3 (pink); C(O)CH3 (violet).
angles between the mean plane defined by the four meth- cule 6 (Figure 4) is quite different from that of 4. The
ylene bridges linking the aromatic rings [C(1)–C(4)] and calix[4]arene assumes a slightly distorted cone conforma-
the planes of the individual phenyl rings: 147.5° [C(11)– tion as indicated by the interplanar angles between the
C(16)], 88.1° [C(21)–C(26)], 135.8° [C(31)–C(36)], and mean plane of the bridging methylene carbon atoms
80.6° [C(41)–C(46)]. Thus, the two aromatic rings [C(1)–C(4)] and the planes of the phenyl rings [C(n1)–
[C(21)–C(26)] and [C(41)–C(46)] are almost parallel to C(n6)] (n = 1 to 4): 123.5, 119.4, 113.7, and 112.4, respec-
each other (interplanar angle 11.4°). The decrease of the tively. Thus aromatic rings [C(11)–C(16)] and [C(31)–
NO2 to t-Bu separation leads to an O(22)···O(42) distance C(36)] form a dihedral angle of 57.2° with an
of 5.67 Å. The two phenyl rings [C(11)–C(16)] and O(12)···O(32) separation of 4.12 Å; the value for the
[C(31)–C(36)] are tilted so as to place the alkoxy groups [C(21)–C(26)] and [C(41)–C(46)] dihedral angle is 51.8°
inside the cavity (interplanar angle 103.3°), with an [O(22)···O(42) separation of 4.46 Å]. A strong intramo-
O(12)···O(32) separation of 3.33 Å. In this conformation lecular hydrogen bond is found between the phenolic hy-
it is not possible to have any solvent molecule enclathrat- droxy group and one adjacent ether oxygen with
ed within the calixarene cup. One acetonitrile molecule is O(12)···O(22) distance of 2.74 Å. The ‘open’ cone confor-
accommodated in continuous channels within the crystal mation facilitates the inclusion of one dimethyl sulfoxide
lattice.
molecule in the cavity of 6. One methyl group of this di-
methyl sulfoxide enters the cavity provided by the
calix[4]arene and forms C–H···p interactions with the
phenyl rings. The distances of the centroids of rings
[C(n1)–C(n6)] (n = 1 to 4) to the included methyl carbon
Compound 6 crystallizes from dimethyl sulfoxide solu-
tion in the triclinic space group P–1 as a 1:2 complex with
dimethyl sulfoxide.18 The conformation found for mole-
Figure 4 A view of the structure of 6 showing also the numbering
scheme. The hydrogen atoms and solvent molecules are omitted for
clarity.
Figure 3 A view of the structure of 4 showing also the numbering
scheme. The hydrogen atoms and solvent molecules are omitted for
clarity.
Synthesis 2008, No. 5, 754–762 © Thieme Stuttgart · New York

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Monofunctionalization of Tri-urea-mono-acetamides of Calix[4]arenes
757
6.98 (d, 4J = 2.3 Hz, 2 H, ArH), 7.05 (d, 4J = 2.3 Hz, 2 H, ArH), 7.42
(s, 2 H, ArH).
of the second dimethyl sulfoxide molecule [N(16)···O=S 13C{1H} NMR (100.6 MHz, CDCl3): d = 10.1 (CH3), 10.7 (CH3),
are 3.71, 3.60, 3.72, and 3.82 Å, respectively. In addition,
the amide hydrogen forms a hydrogen bond to the oxygen
14.2 (CH3), 23.1 (CH2), 23.6 (CH2), 30.9 [C(CH3)3], 31.1 (CH2),
31.58 [C(CH3)3], 31.62 (CH2), 33.3 [C(CH3)3], 34.1 [C(CH3)3], 61.0
(OCH2), 71.3 (OCH2), 76.8 (OCH2), 77.2 (OCH2), 123.4 (CH),
distance of 2.91 Å].
In summary, a multistep strategy for the synthesis of the
calix[4]arene derivatives 14, in which one carboxylic
(narrow rim) and one acetamide (wide rim) function are
introduced in the same aromatic ring was elaborated. The
three remaining rings were substituted by urea and propyl
groups at the wide and the narrow rim respectively. It was
shown that the precursors 13 form the desired tetramers in
apolar, aprotic solvents in spite of the presence of an ad-
ditional polar group in the molecule. Derivatives of this
type thus can be considered as cores for dendritic struc-
tures. Two intermediate compounds 4 and 6 were addi-
tionally characterized by X-ray crystal structure analysis.
124.7 (CH), 125.0 (CH), 126.5 (CH), 132.5 (C), 133.2 (C), 135.4
(C), 142.9 (C), 144.5 (C), 145.3 (C), 153.0 (C), 154.4 (C), 160.1
(C), 168.9 (C).
MS (FD): m/z (%) = 851.2 (100) [M + H]+.
5-Amino-11,17,23-tri-tert-butyl-25,26,27-tripropoxy-28-
[(ethoxycarbonyl)methoxy]calix[4]arene (5)
Calix[4]arene 4 (3.20 g, 3.76 mmol) was dissolved in toluene–
EtOH (1:1, 40 mL) and hydrogenated at r.t. for 8 h in the presence
of Raney Ni. The catalyst was filtered off and solvents were evapo-
rated. The residue was triturated with MeOH; the thus formed pre-
cipitate was filtered off and dried. Compound 5 (2.84 g, 92%) was
obtained as a white powder; mp 174–176 °C.
1H NMR (400 MHz, CDCl3): d = 0.85 [s, 9 H, C(CH3)3], 0.92 (t,
3J = 7.4 Hz, 6 H, CH3), 1.08 (t, 3J = 7.4 Hz, 3 H, CH3), 1.27 [s, 18
H, C(CH3)3], 1.31 (t, 3J = 7.0 Hz, 3 H, OCH2CH3), 2.05–1.89 (m, 6
H, CH2), 2.89 (br s, 2 H, NH2), 3.03 (d, 2J = 12.5 Hz, 2 H,
ArCH2Ar), 3.13 (d, 2J = 12.5 Hz, 2 H, ArCH2Ar), 3.73 (t, 3J = 7.4
Hz, 2 H, OCH2), 3.95 (t, 3J = 7.4 Hz, 4 H, OCH2), 4.23 (q, 3J = 7.0
1
Melting points are uncorrected. H and 13C NMR spectra were re-
corded on a Bruker Avance DRX 400 spectrometer at 400 and 100.6
MHz respectively. Chemical shifts are with reference to the residual
solvent peaks. Decoupling and DEPT experiments confirmed the
assignments of the signals. Mass spectra were recorded on a Waters/
Micromass QTof Ultima 3 mass spectrometer. All solvents were
HPLC grade and used without further purification. Column chroma-
tography was performed on silica gel 60 (0.035–0.070 mm, Acros).
As previously verified,19 data for elemental analyses of organic
calixarenes are often misleading, due to inclusion of solvent mole-
cules, and cannot be considered appropriate criteria of purity. How-
ever, the identities of the reported compounds were unambiguously
established by their spectroscopic data.
2
Hz, 2 H, OCH2CH3), 4.43 [s, 2 H, OCH2C(O)], 4.45 (d, J = 12.5
Hz, 4 H, ArCH2Ar), 5.78 (s, 2 H, ArH), 6.38 (s, 2 H, ArH), 6.93 (d,
4J = 2.3 Hz, 2 H, ArH), 7.02 (d, 4J = 2.3 Hz, 2 H, ArH).
13C{1H} NMR (100.6 MHz, CDCl3): d = 10.1 (CH3), 10.7 (CH3),
14.3 (CH3), 23.0 (CH2), 23.6 (CH2), 31.1 [C(CH3)3], 31.2 (CH2),
31.4 (CH2), 31.7 [C(CH3)3], 33.5 [C(CH3)3], 34.0 [C(CH3)3], 60.5
(OCH2), 72.0 (OCH2), 76.6 (OCH2), 77.0 (OCH2), 115.0 (CH),
124.6 (CH), 125.1 (CH), 125.7 (CH), 132.7 (C), 134.0 (C), 134.7
(C), 135.4 (C), 140.4 (C), 143.8 (C), 144.3 (C), 148.1 (C), 153.2
(C), 154.8 (C), 169.8 (C).
Intensity data for compounds 4 and 6 were collected on a STOE
IPDS-II image plate diffractometer using graphite-monochromated
Mo-Ka radiation. The data were corrected for Lorentz and polariza-
tion effects, but only for 6 for absorption effects.20 The structures
were solved using direct methods (SHELXS21) and refined by full-
matrix least-squares techniques against Fo2 (SHELXL-9722). Hy-
drogen atoms were included at calculated positions with fixed dis-
placement parameters. Two H atoms bonded to O and N in 6 were
freely refined. All non-hydrogen atoms were refined anisotropical-
ly. Two tert-butyl groups in 4 and two tert-butyl groups and two S
atoms of the DMSO molecules in 6 are disordered over two posi-
tions. The disordered tert-butyl groups in 6 were restrained to have
similar geometric parameters.23
MS (FD): m/z (%) = 820.8 (100) [M + H]+.
5-Acetamido-11,17,23-tri-tert-butyl-25,26,27-tripropoxy-28-hy-
droxycalix[4]arene (6)
Calix[4]arene 3 (9.40 g, 12.30 mmol) was dissolved in a mixture of
toluene–THF (3:1, 400 mL) and hydrogenated in the presence of
Raney Ni (THF–hexane, 1:10, monitoring by TLC). When the reac-
tion was finished, Ac2O (25.1 g, 0.25 mol) and Et3N (24.9 g, 0.25
mol) were added and the mixture was stirred for 4 h. The catalyst
was filtered off and the soln was evaporated. The residue was dis-
solved in CHCl3 (150 mL), washed with H2O (3 × 70 mL), and dried
(MgSO4). The crude product was crystallized (MeCN) to give com-
pound 6 (9.50 g, 99%) as white crystals; mp 214–216 °C.
5-Nitro-11,17,23-tri-tert-butyl-25,26,27-tripropoxy-28-
[(ethoxycarbonyl)methoxy]calix[4]arene (4)
A mixture of calix[4]arene 314 (4.30 g, 5.63 mmol), Na2CO3 (0.89
g, 8.40 mmol), and ethyl bromoacetate (1.41 g, 8.44 mmol) was re-
fluxed for 4 d in MeCN (50 mL). The sodium salts were filtered off,
washed with CHCl3 and the solvents were evaporated. The residue
was dissolved in MeOH–acetone (5:1, 30 mL) and H2O (30 mL)
was added to the soln. The turbid aqueous phase was decanted and
the residue was triturated with MeOH. The thus formed precipitate
was filtered off and dried to afford calix[4]arene 4 (3.78 g, 79%) as
a white powder; mp 195–197 °C.
1H NMR (400 MHz, DMSO-d6): d = 0.92 [s, 18 H, C(CH3)3], 0.94
(t, 3J = 7.3 Hz, 3 H, CH3), 1.11 (t, 3J = 7.3 Hz, 6 H, CH3), 1.24 [s, 9
H, C(CH3)3], 1.96–1.83 (m, 4 H, CH2), 1.96 [s, 3 H, NHC(O)CH3],
2.18–2.08 (m, 2 H, CH2), 3.19 (d, 2J = 12.2 Hz, 2 H, ArCH2Ar), 3.25
(d, 2J = 12.2 Hz, 2 H, ArCH2Ar), 3.69–3.63 (m, 2 H, OCH2), 3.80–
3.73 (m, 4 H, OCH2), 4.16 (d, 2J = 12.2 Hz, 2 H, ArCH2Ar), 4.29 (d,
4
2J = 12.2 Hz, 2 H, ArCH2Ar), 6.34 (s, 1 H, OH), 6.59 (d, J = 2.0
Hz, 2 H, ArH), 6.79 (d, 4J = 2.0 Hz, 2 H, ArH), 7.17 (s, 2 H, ArH),
7.26 (s, 2 H, ArH), 9.54 (s, 1 H, NH).
1H NMR (400 MHz, CDCl3): d = 0.77 [s, 9 H, C(CH3)3], 0.95 (t,
3J = 7.4 Hz, 6 H, CH3), 1.08 (t, 3J = 7.4 Hz, 3 H, CH3), 1.27 [s, 18
H, C(CH3)3], 1.31 (t, 3J = 7.4 Hz, 3 H, OCH2CH3), 2.05–1.89 (m, 6
H, CH2), 3.17 (d, 2J = 12.9 Hz, 2 H, ArCH2Ar), 3.24 (d, 2J = 12.9
Hz, 2 H, ArCH2Ar), 3.73 (t, 3J = 7.4 Hz, 2 H, OCH2), 3.92–3.85 (m,
2 H, OCH2), 4.06–3.99 (m, 2 H, OCH2), 4.24 (q, 3J = 7.4 Hz, 2 H,
OCH2CH3), 4.43 (d, 2J = 12.9 Hz, 2 H, ArCH2Ar), 4.57 (d, 2J = 12.9
Hz, 2 H, ArCH2Ar), 4.66 [s, 2 H, OCH2C(O)], 6.40 (s, 2 H, ArH),
13C{1H} NMR (100.6 MHz, DMSO-d6): d = 9.6 (CH3), 10.5 (CH3),
22.2 (CH2), 22.9 (CH2), 23.7 [C(O)CH3], 30.1 (CH2), 30.8
[C(CH3)3], 31.0 (CH2), 31.2 [C(CH3)3], 33.4 [C(CH3)3], 33.7
[C(CH3)3], 76.1 (OCH2), 77.1 (OCH2), 119.5 (CH), 124.1 (CH),
125.0 (CH), 125.2 (CH), 128.1 (CH), 128.8 (CH), 129.2 (C), 130.7
(C), 131.3 (C), 133.0 (C), 134.7 (C), 144.7 (C), 144.8 (C), 148.5
(C), 151.5 (C), 153.0 (C), 167.3 (C).
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Y. Rudzevich et al.
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MS (FD): m/z (%) = 776.6 (100) [M + H]+.
5-Phthalimido-11,17,23-tri-tert-butyl-25,26,27-tripropoxy-28-
[10-(ethoxycarbonyl)decyloxy]calix[4]arene (8b)
5-Acetamido-11,17,23-tri-tert-butyl-25,26,27-tripropoxy-28-
[10-(ethoxycarbonyl)decyloxy]calix[4]arene (7)
Hydrolysis of the acetamide: A soln of NaOH (10.30 g, 0.26 mol) in
H2O (40 mL) was added to the soln of calix[4]arene 7 (12.70 g,
12.84 mmol) in THF–MeOH (1:2, 210 mL) and the mixture was re-
fluxed for 4 d. AcOH (20 mL) was added and the solvents were
evaporated. The residue was dissolved in CHCl3 (200 mL) and
washed with H2O (3 × 50 mL). The organic layer was dried
(MgSO4) and evaporated and the residue was refluxed in EtOH (200
mL) in the presence of H2SO4 (5 mL) for 8 h. After evaporation, the
residue was dissolved in CHCl3 (200 mL), washed with H2O (3 × 50
mL) and 5% aq Et3N (3 × 50 mL). The organic layer was dried
(MgSO4) and evaporated and the product was purified by column
chromatography (EtOAc–hexane, 1:4). The desired amino com-
pound (10.0 g, 80%) was obtained as a light yellow oil.
A slurry of the calix[4]arene 6 (10.70 g, 13.79 mmol) and NaH (0.50
g, 20.7 mmol) in DMF (200 mL) was stirred for 1 h. Then ethyl 11-
bromoundecanoate (6.06 g, 20.68 mmol) was added and the stirring
was continued at r.t. for 3 d. AcOH (5 mL) and then H2O (200 mL)
were added and the mixture was extracted with CHCl3 (3 × 50 mL).
The combined organic phases were dried (MgSO4) and evaporated.
The crude product was purified by column chromatography
(CHCl3–hexane, 2:1 then 6:1) to give 7 (12.7 g, 93%) as a light yel-
low oil.
1H NMR (400 MHz, DMSO-d6): d = 0.75 [s, 9 H, C(CH3)3], 0.91 (t,
3J = 7.3 Hz, 6 H, CH3), 1.31–1.03 [m, 36 H, CH3, CH2, OCH2CH3,
C(CH3)3], 1.50 (m, 4 H, CH2), 1.80 [s, 3 H, C(O)CH3], 1.99–1.81
(m, 6 H, CH2), 2.24 [t, 3J = 6.6 Hz, 2 H, C(O)CH2], 3.02 (d, 2J = 12.7
1H NMR (400 MHz, CDCl3): d = 0.78 [s, 9 H, C(CH3)3], 0.89 (t,
3J = 7.3 Hz, 6 H, CH3), 1.09 (t, 3J = 7.3 Hz, 3 H, CH3), 1.24 (t, 3J =
7.2 Hz, 3 H, OCH2CH3), 1.30 (m, 8 H, CH2), 1.33 [s, 18 H,
C(CH3)3], 1.63–1.45 (m, 6 H, CH2), 1.94–1.78 (m, 4 H, CH2), 2.08–
1.98 (m, 4 H, CH2), 2.28 [t, 3J = 7.6 Hz, 2 H, C(O)CH2], 2.72 (s, 2
2
Hz, 2 H, ArCH2Ar), 3.09 (d, J = 12.7 Hz, 2 H, ArCH2Ar), 3.67–
3.60 (m, 4 H, OCH2), 3.88–3.77 (m, 4 H, OCH2), 4.03 (q, 3J = 7.0
Hz, 2 H, OCH2CH3), 4.27 (d, 2J = 12.7 Hz, 2 H, ArCH2Ar), 4.31 (d,
2J = 12.7 Hz, 2 H, ArCH2Ar), 6.30 (s, 2 H, ArH), 6.80 (s, 2 H, ArH),
6.89 (s, 2 H, ArH), 6.98 (s, 2 H, ArH), 9.01 (s, 1 H, NH).
2
H, NH2), 2.99 (d, 2J = 12.7 Hz, 2 H, ArCH2Ar), 3.11 (d, J = 12.7
Hz, 2 H, ArCH2Ar), 3.60 (t, 3J = 6.9 Hz, 2 H, OCH2), 3.69 (t, 3J =
6.9 Hz, 2 H, OCH2), 4.01–3.90 (m, 4 H, OCH2), 4.11 (q, 3J = 7.2 Hz,
13C{1H} NMR (100.6 MHz, DMSO-d6): d = 9.6 (CH3), 10.5 (CH3),
14.0 (CH3), 22.6 (CH2), 22.9 (CH2), 23.8 [C(O)CH3], 25.9 (CH2),
28.3 (CH2), 28.5 (CH2), 28.8 (CH2), 28.9 (CH2), 29.0 (CH2), 29.2
(CH2), 29.7 (CH2), 30.4 (CH2), 30.6 [C(CH3)3], 31.3 [C(CH3)3],
32.9 [C(CH3)3], 33.5 [C(CH3)3], 59.5 (OCH2), 74.8 (OCH2), 76.0
(OCH2), 76.3 (OCH2), 117.6 (CH), 124.2 (CH), 124.8 (CH), 125.4
(CH), 132.0 (C), 132.8 (C), 133.6 (C), 133.9 (C), 134.6 (C), 143.2
(C), 143.6 (C), 150.5 (C), 152.6 (C), 154.0 (C), 166.5 (C), 172.7
(C).
2
2 H, OCH2CH3), 4.34 (d, J = 12.7 Hz, 2 H, ArCH2Ar), 4.43 (d,
2J = 12.7 Hz, 2 H, ArCH2Ar), 5.67 (s, 2 H, ArH), 6.26 (s, 2 H, ArH),
7.00 (d, 4J = 2.5 Hz, 2 H, ArH), 7.08 (d, 4J = 2.5 Hz, 2 H, ArH).
13C{1H} NMR (100.6 MHz, CDCl3): d = 9.9 (CH3), 10.8 (CH3),
14.2 (CH3), 23.0 (CH2), 23.6 (CH2), 25.0 (CH2), 26.5 (CH2), 29.1
(CH2), 29.3 (CH2), 29.5 (CH2), 29.6 (CH2), 29.7 (CH2), 30.4 (CH2),
31.0 [C(CH3)3], 31.1 (CH2), 31.2 (CH2), 31.7 [C(CH3)3], 33.5
(CH2), 34.0 [C(CH3)3], 34.8 [C(CH3)3], 60.1 (OCH2), 75.6 (OCH2),
76.5 (OCH2), 77.0 (OCH2), 114.7 (CH), 124.5 (CH), 125.2 (CH),
125.7 (CH), 132.3 (C), 133.8 (C), 135.4 (C), 136.0 (C), 139.8 (C),
143.7 (C), 144.3 (C), 144.4 (C), 148.7 (C), 152.9 (C), 155.0 (C).
MS (FD): m/z (%) = 988.9 (100) [M]+.
5-Phthalimido-11,17,23-tri-tert-butyl-25,26,27-tripropoxy-28-
[(ethoxycarbonyl)methoxy]calix[4]arene (8a)
MS (FD): m/z (%) = 947.0 (100) [M]+.
A slurry of calix[4]arene 5 (2.36 g, 2.88 mmol), Zn(OAc)2 (1.05 g,
5.75 mmol), and phthalic anhydride (0.85 g, 5.75 mmol) in pyridine
(25 mL) was refluxed for 3 d. Then H2O (30 mL) was added and the
thus formed precipitate was filtered off and washed with 1 M HCl,
H2O, and MeOH. After drying in air, compound 8a (2.00 g, 73%)
was obtained as a beige powder; mp 207–209 °C.
1H NMR (400 MHz, CDCl3): d = 0.97 [s, 18 H, C(CH3)3], 0.99 (t,
3J = 7.4 Hz, 3 H, CH3), 1.02 (t, 3J = 7.4 Hz, 6 H, CH3), 1.17 [s, 9 H,
C(CH3)3], 1.29 (t, 3J = 7.2 Hz, 3 H, OCH2CH3), 2.14–1.88 (m, 2 H,
CH2), 1.97–1.88 (m, 4 H, CH2), 3.14 (d, 2J = 12.5 Hz, 2 H,
ArCH2Ar), 3.24 (d, 2J = 12.9 Hz, 2 H, ArCH2Ar), 3.77–3.72 (m, 4
H, OCH2), 3.87 (t, 3J = 7.8 Hz, 2 H, OCH2), 4.21 (q, 3J = 7.2 Hz, 2
H, OCH2CH3), 4.42 (d, 2J = 12.5 Hz, 2 H, ArCH2Ar), 4.70 (d, 2J =
12.9 Hz, 2 H, ArCH2Ar), 5.00 [s, 2 H, OCH2C(O)], 6.63–6.62 (m, 4
H, ArH), 6.94 (s, 2 H, ArH), 7.10 (s, 2 H, ArH), 7.75–7.73 (m, 2 H,
HPhth), 7.92–7.90 (m, 2 H, HPhth).
13C{1H} NMR (100.6 MHz, CDCl3): d = 10.2 (CH3), 10.6 (CH3),
14.2 (CH3), 23.4 (CH2), 23.5 (CH2), 31.0 (CH2), 31.4 [C(CH3)3],
31.5 [C(CH3)3], 31.8 (CH2), 33.8 [C(CH3)3], 33.9 [C(CH3)3], 60.4
(OCH2), 70.3 (OCH2), 76.9 (OCH2), 77.3 (OCH2), 123.5 (CH),
124.9 (CH), 125.1 (CH), 125.4 (CH), 126.0 (C), 126.1 (CH), 131.8
(C), 132.0 (C), 132.8 (C), 134.0 (CH), 134.9 (C), 136.0 (C), 144.6
(C), 144.7 (C), 153.3 (C), 154.2 (C), 155.1 (C), 167.2 (C), 170.6
(C).
Protection by phthalimide:
A mixture of the monoamino
calix[4]arene (7.00 g, 7.39 mmol), Zn(OAc)2 (4.06 g, 22.16 mmol),
and phthalic anhydride (3.28 g, 22.16 mmol) was refluxed in pyri-
dine (100 mL) for 3 d. H2O (50 mL) was added to the suspension
and the oily precipitate was separated, dissolved in CHCl3 (150
mL), and washed with 1 M HCl (3 × 50 mL) and H2O (5 × 50 mL).
The residue obtained after evaporation was purified by column
chromatography (CHCl3–hexane, 2:1) to afford 8b (4.80 g, 60%) as
a glassy solid.
1H NMR (400 MHz, CDCl3): d = 1.01–0.97 (m, 9 H, CH3), 1.02 [s,
9 H, C(CH3)3], 1.06 [s, 18 H, C(CH3)3], 1.25 (t, J = 7.0 Hz, 3 H,
3
OCH2CH3), 1.39–1.32 (m, 12 H, CH2), 1.63 (m, 2 H, CH2), 2.07–
3
1.95 (m, 8 H, CH2), 2.29 [t, J = 7.6 Hz, 2 H, C(O)CH2], 3.12 (d,
2J = 12.7 Hz, 2 H, ArCH2Ar), 3.17 (d, 2J = 12.7 Hz, 2 H, ArCH2Ar),
3.81–3.77 (m, 4 H, OCH2), 3.87 (t, 3J = 7.6 Hz, 2 H, OCH2), 3.95 (t,
3J = 7.6 Hz, 2 H, OCH2), 4.12 (q, 3J = 7.0 Hz, 2 H, OCH2CH3), 4.43
2
2
(d, J = 12.7 Hz, 2 H, ArCH2Ar), 4.46 (d, J = 12.7 Hz, 2 H,
ArCH2Ar), 6.74 (s, 4 H, ArH), 6.77 (s, 2 H, ArH), 7.03 (s, 2 H,
ArH), 7.73–7.71 (m, 2 H, HPhth), 7.89–7.87 (m, 2 H, HPhth).
13C{1H} NMR (100.6 MHz, CDCl3): d = 10.3 (CH3), 10.4 (CH3),
14.3 (CH3), 23.2 (CH2), 23.3 (CH2), 23.4 (CH2), 25.0 (CH2), 26.2
(CH2), 29.2 (CH2), 29.3 (CH2), 29.5 (CH2), 29.8 (CH2), 31.0 (CH2),
31.1 (CH2), 31.2 [C(CH3)3], 31.4 [C(CH3)3], 33.7 (CH2), 33.8
[C(CH3)3], 34.4 [C(CH3)3], 60.1 (OCH2), 75.4 (OCH2), 76.7
(OCH2), 77.1 (OCH2), 123.3 (CH), 124.9 (CH), 125.1 (CH), 125.3
(CH), 125.8 (C), 131.9 (C), 132.0 (C), 132.6 (C), 133.5 (C), 133.9
(CH), 134.2 (C), 135.8 (C), 144.3 (C), 144.4 (C), 144.47 (C), 144.50
(C), 153.6 (C), 153.8 (C), 155.7 (C), 167.0 (C), 173.9 (C).
MS (FD): m/z (%) = 950.8 (100) [M + H]+.
MS (FD): m/z (%) = 1075.3 (100) [M]+.
Synthesis 2008, No. 5, 754–762 © Thieme Stuttgart · New York

PAPER
Monofunctionalization of Tri-urea-mono-acetamides of Calix[4]arenes
759
3
5-Phthalimido-11,17,23-trinitro-25,26,27-tripropoxy-28-
[(ethoxycarbonyl)methoxy]calix[4]arene (9a); Typical Proce-
dure
Fuming HNO3 (3.6 mL) was cautiously added to the vigorously
stirred soln of calix[4]arene 8a (2.60 g, 2.74 mmol) and AcOH (7.8
mL) in CH2Cl2 (260 mL). The mixture was stirred at r.t. for 1 h. The
soln was washed with H2O (5 × 50 mL), dried (MgSO4), and evap-
orated. The residue was triturated with MeOH, the thus formed pre-
cipitate was filtered off and dried in air to yield calix[4]arene 9a
(2.23 g, 89%) as a beige powder; mp 225–227 °C.
1H NMR (400 MHz, CDCl3): d = 0.94 (t, J = 7.4 Hz, 6 H, CH3),
1.06 (t, 3J = 7.4 Hz, 3 H, CH3), 1.29 (t, 3J = 7.1 Hz, 3 H, OCH2CH3),
1.92–1.83 (m, 6 H, CH2), 3.19 (d, 2J = 14.1 Hz, 2 H, ArCH2Ar), 3.36
(d, 2J = 14.1 Hz, 2 H, ArCH2Ar), 3.86 (t, 3J = 7.4 Hz, 2 H, OCH2),
3.99–3.93 (m, 2 H, OCH2), 4.18–4.12 (m, 2 H, OCH2), 4.22 (q, 3J =
7.1 Hz, 2 H, OCH2CH3), 4.37 [s, 2 H, OCH2C(O)], 4.51 (d, 2J = 14.1
Hz, 2 H, ArCH2Ar), 4.54 (d, 2J = 14.1 Hz, 2 H, ArCH2Ar), 5.63 (s,
2 H, ArH), 7.29 (s, 2 H, ArH), 7.81 (s, 4 H, ArH).
13C{1H} NMR (100.6 MHz, CDCl3): d = 10.0 (CH3), 10.3 (CH3),
14.2 (CH3), 23.2 (CH2), 23.3 (CH2), 31.1 (CH2), 31.2 (CH2), 60.8
(OCH2), 71.7 (OCH2), 77.5 (OCH2), 77.6 (OCH2), 114.7 (CH),
123.6 (CH), 123.7 (CH), 124.7 (CH), 133.2 (C), 135.0 (C), 135.8
(C), 137.3 (C), 142.4 (C), 142.5 (C), 142.6 (C), 147.6 (C), 161.4
(C), 162.9 (C), 169.1 (C).
3
1H NMR (400 MHz, CDCl3): d = 0.99 (t, J = 7.2 Hz, 6 H, CH3),
1.04 (t, 3J = 7.2 Hz, 3 H, CH3), 1.32 (t, 3J = 7.2 Hz, 3 H, OCH2CH3),
2.00–1.87 (m, 6 H, CH2), 3.38 (d, 2J = 13.7 Hz, 2 H, ArCH2Ar), 3.40
(d, 2J = 13.7 Hz, 2 H, ArCH2Ar), 3.84 (t, 3J = 7.2 Hz, 2 H, OCH2),
4.09–4.03 (m, 2 H, OCH2), 4.21–4.14 (m, 2 H, OCH2), 4.26 (q, 3J =
7.2 Hz, 2 H, OCH2CH3), 4.54 [s, 2 H, OCH2C(O)], 4.54 (d, 2J = 13.7
Hz, 2 H, ArCH2Ar), 4.68 (d, 2J = 13.7 Hz, 2 H, ArCH2Ar), 6.63 (s,
2 H, ArH), 7.47 (s, 2 H, ArH), 7.72–7.70 (m, 2 H, HPhth), 7.77 (d,
4J = 2.4 Hz, 2 H, ArH), 7.79 (d, 4J = 2.4 Hz, 2 H, ArH), 7.85–7.83
(m, 2 H, HPhth).
MS (FD): m/z (%) = 787.2 (100) [M + H]+.
5-Amino-11,17,23-trinitro-25,26,27-tripropoxy-28-[10-(ethoxy-
carbonyl)decyloxy]calix[4]arene (10b)
Following the typical procedure for 10a gave calix[4]arene 10b in
69% yield as a yellow foam after column chromatography (EtOAc–
hexane, 1:4 then 1:3).
13C{1H} NMR (100.6 MHz, CDCl3): d = 10.1 (CH3), 10.3 (CH3),
14.3 (CH3), 23.2 (CH2), 23.3 (CH2), 31.1 (CH2), 31.3 (CH2), 61.1
(OCH2), 71.7 (OCH2), 77.6 (OCH2), 77.9 (OCH2), 123.7 (CH),
124.0 (CH), 124.2 (CH), 124.6 (CH), 126.6 (CH), 127.3 (C), 131.5
(C), 133.5 (C), 134.3 (CH), 134.4 (C), 135.5 (C), 136.4 (C), 142.8
(C), 143.6 (C), 154.3 (C), 161.0 (C), 162.3 (C), 166.6 (C), 168.7
(C).
3
1H NMR (400 MHz, CDCl3): d = 0.93 (t, J = 7.3 Hz, 6 H, CH3),
1.07 (t, 3J = 7.3 Hz, 3 H, CH3), 1.24 (t, 3J = 7.1 Hz, 3 H, OCH2CH3),
1.29 (m, 8 H, CH2), 1.33 (m, 2 H, CH2), 1.44 (m, 2 H, CH2), 1.60
(m, 2 H, CH2), 1.82–1.75 (m, 2 H, CH2), 1.93–1.85 (m, 6 H, CH2),
2.27 [t, 3J = 7.6 Hz, 2 H, C(O)CH2], 3.07 (br s, 2 H, NH2), 3.19 (d,
2J = 14.2 Hz, 2 H, ArCH2Ar), 3.35 (d, 2J = 13.7 Hz, 2 H, ArCH2Ar),
3.67 (t, 3J = 6.7 Hz, 2 H, OCH2), 3.84 (t, 3J = 6.7 Hz, 2 H, OCH2),
4.00–3.93 (m, 2 H, OCH2), 4.15–4.08 (m, 4 H, OCH2), 4.37 (d, 2J =
14.2 Hz, 2 H, ArCH2Ar), 4.52 (d, 2J = 13.7 Hz, 2 H, ArCH2Ar), 5.55
(s, 2 H, ArH), 7.22 (s, 2 H, ArH), 7.89 (s, 4 H, ArH).
MS (FD): m/z (%) = 917.6 (100) [M + H]+.
5-Phthalimido-11,17,23-trinitro-25,26,27-tripropoxy-28-[10-
(ethoxycarbonyl)decyloxy]calix[4]arene (9b)
Following the typical procedure for 9a produced calix[4]arene 9b in
95% yield as a lightly yellow, glassy solid after column chromatog-
raphy (EtOAc–hexane, 1:3).
13C{1H} NMR (100.6 MHz, CDCl3): d = 9.9 (CH3), 10.4 (CH3),
14.2 (CH3), 23.2 (CH2), 23.3 (CH2), 25.0 (CH2), 26.4 (CH2), 29.1
(CH2), 29.3 (CH2), 29.4 (CH2), 29.6 (CH2), 30.2 (CH2), 31.1 (CH2),
34.3 (CH2), 60.2 (OCH2), 75.6 (OCH2), 77.6 (OCH2), 114.6 (CH),
123.5 (CH), 123.8 (CH), 124.9 (CH), 133.1 (C), 134.8 (C), 135.9
(C), 137.7 (C), 142.5 (C), 142.6 (C), 161.2 (C), 163.0 (C).
3
1H NMR (400 MHz, CDCl3): d = 0.97 (t, J = 7.3 Hz, 6 H, CH3),
1.05 (t, 3J = 7.3 Hz, 3 H, CH3), 1.24 (t, 3J = 7.1 Hz, 3 H, OCH2CH3),
1.31 (m, 8 H, CH2), 1.38 (m, 2 H, CH2), 1.48 (m, 2 H, CH2), 1.61
(m, 2 H, CH2), 2.00–1.84 (m, 8 H, CH2), 2.28 [t, 3J = 7.6 Hz, 2 H,
C(O)CH2], 3.37 (d, 2J = 13.7 Hz, 4 H, ArCH2Ar), 3.85–3.81 (m, 4
H, OCH2), 4.17–4.04 (m, 6 H, OCH2CH3, OCH2), 4.51 (d, 2J = 13.7
Hz, 2 H, ArCH2Ar), 4.53 (d, 2J = 13.7 Hz, 2 H, ArCH2Ar), 7.39 (s,
2 H, ArH), 6.50 (s, 2 H, ArH), 7.70–7.68 (m, 2 H, HPhth), 7.82–7.80
(m, 2 H, HPhth), 7.86 (s, 4 H, ArH).
MS (FD): m/z (%) = 912.7 (100) [M]+.
5-Acetamido-11,17,23-trinitro-25,26,27-tripropoxy-28-
[(ethoxycarbonyl)methoxy]calix[4]arene (11a); Typical
Procedure
Ac2O (4 mL) and Et3N (5 mL) were added to the soln of calix[4]ar-
ene 10a (1.50 g, 1.91 mmol) in CHCl3 (10 mL) and the mixture was
stirred for 10 h. After the addition of CHCl3 (30 mL) the excess
Ac2O was quenched with 1 M NaHCO3. The organic layer was
washed with H2O (4 × 20 mL), dried (MgSO4), and evaporated. The
residue was triturated (EtOH–H2O, 1:2, 30 mL) and the thus formed
solid was filtered off and dried in air to give calix[4]arene 11a (1.20
g, 76%) as a brown powder; mp 173–175 °C.
13C{1H} NMR (100.6 MHz, CDCl3): d = 9.9 (CH3), 10.3 (CH3),
14.2 (CH3), 23.2 (CH2), 23.3 (CH2), 24.9 (CH2), 26.3 (CH2), 29.1
(CH2), 29.3 (CH2), 29.4 (CH2), 29.6 (CH2), 30.3 (CH2), 31.1 (CH2),
34.3 (CH2), 60.2 (OCH2), 76.0 (OCH2), 76.4 (OCH2), 77.9 (OCH2),
123.6 (CH), 124.1 (CH), 124.7 (CH), 126.3 (CH), 126.5 (C), 131.5
(C), 133.2 (C), 134.0 (C), 134.1 (CH), 135.6 (C), 136.8 (C), 142.8
(C), 143.7 (C), 154.9 (C), 160.7 (C), 162.5 (C), 166.6 (C), 173.8
(C).
3
1H NMR (400 MHz, CDCl3): d = 0.94 (t, J = 7.4 Hz, 6 H, CH3),
MS (FD): m/z (%) = 1043.0 (100) [M + H]+.
1.07 (t, 3J = 7.4 Hz, 3 H, CH3), 1.30 (t, 3J = 7.2 Hz, 3 H, OCH2CH3),
1.94–1.83 (m, 6 H, CH2), 2.01 [s, 3 H, C(O)CH3], 3.32 (d, 2J = 14.5
Hz, 2 H, ArCH2Ar), 3.36 (d, 2J = 14.5 Hz, 2 H, ArCH2Ar), 3.85 (t,
3J = 7.4 Hz, 2 H, OCH2), 4.02–3.95 (m, 2 H, OCH2), 4.18–4.11 (m,
5-Amino-11,17,23-trinitro-25,26,27-tripropoxy-28-[(ethoxycar-
bonyl)methoxy]calix[4]arene (10a); Typical Procedure
3
HCl (37%, 10 mL) was added to the soln of calix[4]arene 9a (1.00
g, 1.11 mmol) in EtOH–toluene (1:1, 60 mL). The turbid mixture
was refluxed until a clear soln was formed (~4 d) and then concen-
trated to ~20 mL. Then toluene (10 mL) was added and the excess
HCl was neutralized by 1 M NaHCO3. The organic layer was
washed with H2O (20 mL), dried (MgSO4), and evaporated. The
residue was triturated with MeOH, dried, dissolved in EtOAc and
passed through a short column. Calix[4]arene 10a (0.62 g, 72%)
was obtained as a pale brown powder; mp 221–223 °C.
2 H, OCH2), 4.23 (q, J = 7.2 Hz, 2 H, OCH2CH3), 4.40 [s, 2 H,
2
2
OCH2C(O)], 4.52 (d, J = 14.5 Hz, 2 H, ArCH2Ar), 4.56 (d, J =
14.5 Hz, 2 H, ArCH2Ar), 6.42 (s, 2 H, ArH), 6.63 (s, 1 H, NH), 7.20
(s, 2 H, ArH), 7.85 (s, 2 H, ArH), 7.86 (s, 2 H, ArH).
13C{1H} NMR (100.6 MHz, CDCl3): d = 9.9 (CH3), 10.3 (CH3),
14.2 (CH3), 23.1 (CH2), 23.3 (CH2), 24.0 [C(O)CH3], 31.0 (CH2),
31.1 (CH2), 60.9 (OCH2), 71.5 (OCH2), 77.6 (OCH2), 77.7 (OCH2),
120.5 (CH), 123.5 (CH), 123.9 (CH), 124.7 (CH), 133.2 (C), 133.4
(C), 135.1 (C), 135.8 (C), 137.0 (C), 142.5 (C), 151.6 (C), 161.5
(C), 162.7 (C), 168.4 (C), 168.8 (C).
Synthesis 2008, No. 5, 754–762 © Thieme Stuttgart · New York

760
Y. Rudzevich et al.
PAPER
MS (FD): m/z (%) = 829.5 (100) [M + H]+.
(s, 2 H, ArH), 6.05 (s, 2 H, ArH), 6.06 (s, 2 H, ArH), 6.63 (s, 2 H,
ArH), 9.19 (s, 1 H, NH).
5-Acetamido-11,17,23-trinitro-25,26,27-tripropoxy-28-[10-
(ethoxycarbonyl)decyloxy]calix[4]arene (11b)
Following the typical procedure for 11a gave monoacetamide 11b
in 98% yield as a yellow foam after column chromatography
(EtOAc–hexane, 1:3 then 1:1).
13C{1H} NMR (100.6 MHz, DMSO-d6): d = 10.0 (CH3), 10.2
(CH3), 14.0 (CH3), 22.5 (CH2), 22.6 (CH2), 23.4 [C(O)CH3], 24.3
(CH2), 25.7 (CH2), 28.3 (CH2), 28.5 (CH2), 28.7 (CH2), 28.9 (CH2),
29.0 (CH2), 29.5 (CH2), 30.6 (CH2), 30.7 (CH2), 33.4 (CH2), 59.5
(OCH2), 74.5 (OCH2), 76.1 (OCH2), 76.1 (OCH2), 114.0 (CH),
114.3 (CH), 120.5 (CH), 132.6 (C), 134.0 (C), 134.1 (C), 134.3 (C),
134.9 (C), 141.7 (C), 142.2 (C), 147.4 (C), 147.6 (C), 152.2 (C),
167.4 (C), 172.7 (C).
3
1H NMR (400 MHz, CDCl3): d = 0.92 (t, J = 7.3 Hz, 6 H, CH3),
1.08 (t, 3J = 7.3 Hz, 3 H, CH3), 1.23 (t, 3J = 7.1 Hz, 3 H, OCH2CH3),
1.29 (m, 8 H, CH2), 1.34 (m, 2 H, CH2), 1.60 (m, 2 H, CH2), 1.45
(m, 2 H, CH2), 1.83–1.76 (m, 2 H, CH2), 1.92–1.84 (m, 6 H, CH2),
1.99 [s, 3 H, C(O)CH3], 2.27 [t, 3J = 7.6 Hz, 2 H, C(O)CH2], 3.30
MS (FD): m/z (%) = 864.4 (100) [M]+.
2
2
(d, J = 14.2 Hz, 2 H, ArCH2Ar), 3.36 (d, J = 14.2 Hz, 2 H,
ArCH2Ar), 3.70 (t, 3J = 6.9 Hz, 2 H, OCH2), 3.83 (t, 3J = 7.1 Hz, 2
H, OCH2), 4.02–3.95 (m, 2 H, OCH2), 4.13–4.07 (m, 4 H, OCH2),
4.42 (d, 2J = 14.2 Hz, 2 H, ArCH2Ar), 4.51 (d, 2J = 14.2 Hz, 2 H,
ArCH2Ar), 6.31 (s, 2 H, ArH), 6.57 (s, 1 H, NH), 7.13 (s, 2 H, ArH),
7.93 (s, 4 H, ArH).
5-Acetamido-11,17,23-tris[3-(4-methylphenyl)ureido]-
25,26,27-tripropoxy-28-[(ethoxycarbonyl)methoxy]calix[4]ar-
ene (13a); Typical Procedure
4-Tolyl isocyanate (1.04 g, 7.80 mmol) was added to the soln of
calix[4]arene 12a (0.72 g, 0.97 mmol) in CH2Cl2 (30 mL) and the
mixture was stirred for 6 h. MeOH (20 mL) was added and the sol-
vents were evaporated. The residue was triturated with MeOH to
form a solid that was filtered off and dried in air to yield calix[4]are-
ne 13a (0.71 g, 65%) as a white powder; mp >240 °C (dec).
13C{1H} NMR (100.6 MHz, CDCl3): d = 9.8 (CH3), 10.4 (CH3),
14.2 (CH3), 23.2 (CH2), 23.3 (CH2), 24.0 [C(O)CH3], 24.9 (CH2),
26.3 (CH2), 29.1 (CH2), 29.2 (CH2), 29.4 (CH2), 29.5 (CH2), 29.6
(CH2), 30.2 (CH2), 31.1 (CH2), 34.3 (CH2), 60.1 (OCH2), 75.6
(OCH2), 77.4 (OCH2), 77.6 (OCH2), 120.4 (CH), 123.4 (CH), 124.0
(CH), 124.9 (CH), 132.6 (C), 133.0 (C), 134.8 (C), 136.1 (C), 137.5
(C), 142.6 (C), 152.3 (C), 161.2 (C), 162.9 (C), 168.4 (C), 173.8
(C).
1H NMR (400 MHz, DMSO-d6): d = 0.93 (t, 3J = 7.4 Hz, 3 H, CH3),
0.99 (t, 3J = 7.4 Hz, 6 H, CH3), 1.23 (t, 3J = 7.6 Hz, 3 H, OCH2CH3),
1.88–1.83 (m, 6 H, CH2), 1.94 [s, 3 H, C(O)CH3], 2.21 (s, 6 H,
TolCH3), 2.22 (s, 3 H, TolCH3), 3.09 (d, 2J = 12.9 Hz, 2 H,
ArCH2Ar), 3.10 (d, 2J = 12.9 Hz, 2 H, ArCH2Ar), 3.82–3.67 (m, 6
H, OCH2), 4.14 (q, 3J = 7.6 Hz, 2 H, OCH2CH3), 4.33 (d, 2J = 12.9
Hz, 2 H, ArCH2Ar), 4.55 (d, 2J = 12.9 Hz, 2 H, ArCH2Ar), 4.75 [s,
2 H, OCH2C(O)], 6.59 (s, 2 H, ArH), 6.62 (s, 2 H, ArH), 6.98 (s, 2
H, ArH), 7.01 (d, 3J = 8.2 Hz, 4 H, HTol), 7.05 (d, 3J = 8.2 Hz, 2 H,
MS (FD): m/z (%) = 954.6 (100) [M]+.
5-Acetamido-11,17,23-triamino-25,26,27-tripropoxy-28-
[(ethoxycarbonyl)methoxy]calix[4]arene (12a); Typical Proce-
dure
Calix[4]arene 11a (1.05 g, 1.27 mmol) was dissolved in toluene–
EtOH (1:1, 30 mL) and hydrogenated at r.t. for 18 h in the presence
of the Raney Ni monitored by TLC (THF). The catalyst was filtered
off and the solvents were evaporated to leave calix[4]arene 12a
(0.78 g, 83%) as a brown powder; mp >190 °C (dec).
3
HTol), 7.12 (s, 2 H, ArH), 7.17 (d, J = 8.2 Hz, 4 H, HTol), 7.29 (d,
3J = 8.2 Hz, 2 H, HTol), 8.02 (s, 2 H, NH), 8.13 (s, 2 H, NH), 8.26 (s,
1 H, NH), 8.34 (s, 1 H, NH), 9.61 [s, 1 H, NHC(O)CH3].
13C{1H} NMR (100.6 MHz, DMSO-d6): d = 9.9 (CH3), 10.3 (CH3),
14.0 (CH3), 20.2 (TolCH3), 22.6 (CH2), 23.8 [C(O)CH3], 30.5
(CH2), 31.1 (CH2), 59.9 (OCH2), 70.4 (OCH2), 76.4 (OCH2), 76.6
(OCH2), 117.9 (CH), 118.0 (CH), 118.1 (CH), 118.2 (CH), 119.2
(CH), 128.9 (CH), 129.0 (CH), 130.1 (C), 130.2 (C), 133.3 (C),
133.4 (C), 133.6 (C), 133.7 (C), 134.6 (C), 135.0 (C), 137.2 (C),
150.6 (C), 151.3 (C), 152.3 (C), 152.4 (C), 167.6 (C), 169.7 (C).
1H NMR (400 MHz, THF-d8): d = 0.93 (t, 3J = 7.6 Hz, 3 H, CH3),
0.97 (t, 3J = 7.6 Hz, 6 H, CH3), 1.23 (t, 3J = 7.1 Hz, 3 H, OCH2CH3),
1.87–1.83 (m, 6 H, CH2), 1.90 [s, 3 H, C(O)CH3], 2.80 (d, 2J = 13.3
2
Hz, 2 H, ArCH2Ar), 2.94 (d, J = 13.3 Hz, 2 H, ArCH2Ar), 3.75–
3.60 (m, 12 H, OCH2 and NH2), 4.13 (q, 3J = 7.1 Hz, 2 H,
OCH2CH3), 4.28 (d, 2J = 13.3 Hz, 2 H, ArCH2Ar), 4.54 (d, 2J = 13.3
Hz, 2 H, ArCH2Ar), 4.60 [s, 2 H, OCH2C(O)], 5.79 (s, 2 H, ArH),
5.81 (s, 2 H, ArH), 6.02 (s, 2 H, ArH), 6.87 (s, 2 H, ArH), 8.68 (s, 1
H, NH).
MS (ESI): m/z (%) = 1160.5 (100) [M + Na]+.
5-Acetamido-11,17,23-tris[3-(4-methylphenyl)ureido]-
25,26,27-tripropoxy-28-[10-(ethoxycarbonyl)decyl-
oxy]calix[4]arene (13b)
Following the typical procedure for 13a, using MeCN in the last
step instead of MeOH. Calix[4]arene 13b was obtained in 86%
yield as a white powder; mp >190–195 °C (dec).
13C{1H} NMR (100.6 MHz, THF-d8): d = 10.7 (CH3), 11.0 (CH3),
14.6 (CH3), 23.9 [C(O)CH3], 24.0 (CH2), 24.1 (CH2), 32.1 (CH2),
32.4 (CH2), 60.5 (OCH2), 71.4 (OCH2), 77.4 (OCH2), 115.51 (CH),
115.55 (CH), 115.59 (CH), 121.4 (CH), 134.7 (C), 135.1 (C), 135.6
(C), 136.4 (C), 136.6 (C), 142.9 (C), 143.5 (C), 149.4 (C), 150.1
(C), 153.5 (C), 167.4 (C), 170.4 (C).
1H NMR (400 MHz, DMSO-d6): d = 1.00–0.94 (m, 9 H, CH3), 1.16
(t, 3J = 7.1 Hz, 3 H, OCH2CH3), 1.37–1.28 (m, 12 H, CH2), 1.51 (m,
2 H, CH2), 1.90 [m, 11 H, CH2, C(O)CH3], 2.22 (s, 9 H, TolCH3),
2.26 [t, 3J = 7.1 Hz, 2 H, C(O)CH2], 3.11–3.06 (m, 4 H, ArCH2Ar),
3.81–3.74 (m, 8 H, OCH2), 4.04 (q, 3J = 7.2 Hz, 2 H, OCH2CH3),
4.33 (d, 2J = 12.7 Hz, 4 H, ArCH2Ar), 6.72 (s, 2 H, ArH), 6.77 (s, 2
H, ArH), 6.82 (s, 2 H, ArH), 7.03–6.99 (m, 8 H, ArH, HTol), 7.21 (d,
3J = 8.3 Hz, 4 H, HTol), 7.27 (d, 3J = 8.3 Hz, 2 H, HTol), 8.11 (s, 2 H,
NH), 8.13 (s, 1 H, NH), 8.21 (s, 2 H, NH), 8.28 (s, 1 H, NH), 9.48
[s, 1 H, NHC(O)CH3].
13C{1H} NMR (100.6 MHz, DMSO-d6): d = 10.0 (CH3), 10.2
(CH3), 14.0 (CH3), 20.2 (CH3), 22.5 (CH2), 22.6 (CH2), 23.7 (CH3),
24.3 (CH2), 25.6 (CH2), 28.3 (CH2), 28.5 (CH2), 28.8 (CH2), 28.9
(CH2), 29.0 (CH2), 29.4 (CH2), 30.6 (CH2), 33.4 (CH2), 59.5
(OCH2), 74.7 (OCH2), 76.2 (OCH2), 76.4 (OCH2), 117.9 (CH),
118.1 (CH), 119.0 (CH), 128.9 (CH), 129.0 (CH), 130.1 (C), 133.2
(C), 133.3 (C), 133.4 (C), 134.0 (C), 134.1 (C), 134.2 (C), 134.4
MS (FD): m/z (%) = 739.4 (100) [M + H]+.
5-Acetamido-11,17,23-triamino-25,26,27-tripropoxy-28-[10-
(ethoxycarbonyl)decyloxy]calix[4]arene (12b)
Following the typical procedure for 12a gave calix[4]arene 12b in
85% yield as a pale solid; mp >117–120 °C (dec).
1H NMR (400 MHz, DMSO–d6, 75 °C): d = 0.92 (t, 3J = 7.6 Hz, 6
H, CH3), 0.97 (t, 3J = 7.6 Hz, 3 H, CH3), 1.18 (t, 3J = 7.1 Hz, 3 H,
OCH2CH3), 1.29 (m, 10 H, CH2), 1.44 (m, 2 H, CH2), 1.54 (m, 2 H,
CH2), 1.88–1.79 [m, 11 H, CH2, C(O)CH3], 2.25 [t, 3J = 7.1 Hz, 2
H, C(O)CH2], 2.82 (d, 2J = 13.2 Hz, 2 H, ArCH2Ar), 2.92 (d, 2J =
13.2 Hz, 2 H, ArCH2Ar), 3.64 (t, 3J = 7.1 Hz, 2 H, OCH2), 3.78–3.70
(m, 6 H, OCH2), 4.09–4.00 (m, 8 H, OCH2CH3, NH2), 4.21 (d, 2J =
13.2 Hz, 2 H, ArCH2Ar), 4.28 (d, 2J = 13.2 Hz, 2 H, ArCH2Ar), 5.86
Synthesis 2008, No. 5, 754–762 © Thieme Stuttgart · New York

PAPER
Monofunctionalization of Tri-urea-mono-acetamides of Calix[4]arenes
761
(C), 137.2 (C), 150.9 (C), 151.0 (C), 151.8 (C), 152.4 (C), 167.4
(C), 172.7 (C).
MS (ESI): m/z (%) = 1286.7 (100) [M + Na]+.
Acknowledgment
We thank the Deutsche Forschungsgemeinschaft for financial sup-
port (Bo 523/14 and SFB 625).
5-Acetamido-11,17,23-tris[3-(4-methylphenyl)ureido]-
25,26,27-tripropoxy-28-(carboxymethoxy)calix[4]arene (14a);
Typical Procedure
A 3 M aq NaOH soln (2 mL) was added to the soln of calix[4]arene
13a (0.60 g, 0.53 mmol) in THF–DMF (3:1, 28 mL). The mixture
was stirred at r.t. for 12 h and AcOH (5 mL) was added to neutralize
the excess NaOH. The soln was concentrated to ~15 mL, H2O (35
mL) was added and the thus formed precipitate was filtered off and
dried in air to give calix[4]arene 14a (0.57 g, 98%) as a white pow-
der; mp >260 °C (dec).
References
(1) Permanent address: Institute of Organic Chemistry, NAS of
Ukraine, Murmanska str. 5, Kyiv-94, 02094 Ukraine.
(2) For X-ray crystal structure analysis.
(3) Rebek, J. Jr. Chem. Commun. 2000, 637.
(4) (a) Castellano, R. K.; Rudkevich, D. M.; Rebek, J. Jr. Proc.
Natl. Acad. Sci. U.S.A. 1997, 94, 7132. (b) Castellano, R.
K.; Rebek, J. Jr. J. Am. Chem. Soc. 1998, 120, 3657.
(5) For self-assembly of tetra-urea calix[4]arenes covalently
connected via their wide rims see: (a) Brody, M. S.;
Schalley, C. A.; Rudkevich, D. M.; Rebek, J. Jr. Angew.
Chem. Int. Ed. 1999, 38, 1640. (b) Podoprygorina, G.;
Janke, M.; Janshoff, A.; Böhmer, V. Supramol. Chem. in
press.
(6) For self-sorting see: Braekers, D.; Peters, C.; Bogdan, A.;
Rudzevich, Y.; Böhmer, V.; Desreux, J. F. J. Org. Chem.
2008, 73, 701.
(7) Rudzevich, Y.; Rudzevich, V.; Moon, C.; Schnell, I.;
Fischer, K.; Böhmer, V. J. Am. Chem. Soc. 2005, 127,
14168.
(8) (a) Rudzevich, Y.; Rudzevich, V.; Schollmeyer, D.;
Thondorf, I.; Böhmer, V. Org. Lett. 2005, 7, 613.
(b) Rudzevich, Y.; Rudzevich, V.; Schollmeyer, D.;
Thondorf, I.; Böhmer, V. Org. Biomol. Chem. 2006, 4, 3938.
(9) (a) Castellano, R. K.; Kim, B. H.; Rebek, J. Jr. J. Am. Chem.
Soc. 1997, 119, 12671. (b) Thondorf, I.; Rudzevich, Y.;
Rudzevich, V.; Böhmer, V. Org. Biomol. Chem. 2007, 5,
2775.
(10) Shivanyuk, A.; Saadioui, M.; Broda, F.; Thondorf, I.;
Vysotsky, M. O.; Rissanen, K.; Kolehmainen, E.; Böhmer,
V. Chem. Eur. J. 2004, 10, 2138.
(11) Also both positions might be functionalized, while the
introduction of four functional groups (requiring no
selectivity) most probably leads to sterical crowding, which
would prevent the formation of dendrimers.
(12) For the monofunctionalization of tetra-urea derivatives see:
Rudzevich, Y.; Fischer, K.; Schmidt, M.; Böhmer, V. Org.
Biomol. Chem. 2005, 3, 3916.
(13) To use calix[4]arenes as universal building blocks, it would
be ideal to functionalize all four positions at the wide rim
(the p-positions of the phenolic units) and at the narrow rim
(the four phenolic OH functions) selectively and
independently.
(14) Rashidi-Ranjbar, P.; Taghvaei-Ganjali, S.; Shaabani, B.;
Akbari, K. Molecules 2000, 5, 941.
(15) Verboom, W.; Bodewes, P. J.; van Essen, G.; Timmerman,
P.; van Hummel, G. J.; Harkema, S.; Reinhoudt, D. N.
Tetrahedron 1995, 51, 499.
1H NMR [400 MHz, DMSO-d6 + CD3CO2D (10%)]: d = 0.84 (t,
3J = 7.4 Hz, 3 H, CH3), 0.93 (t, 3J = 7.4 Hz, 6 H, CH3), 1.88–1.85
(m, 6 H, CH2), 1.94 [s, 3 H, C(O)CH3], 2.19 (s, 6 H, TolCH3), 2.25
(s, 3 H, TolCH3), 3.07 (d, 2J = 12.9 Hz, 2 H, ArCH2Ar), 3.08 (d, 2J
= 12.9 Hz, 2 H, ArCH2Ar), 3.82–3.67 (m, 4 H, OCH2), 3.80 (t, 3J =
7.6 Hz, 2 H, OCH2), 4.32 (d, 2J = 12.9 Hz, 2 H, ArCH2Ar), 4.47 (d,
2J = 12.9 Hz, 2 H, ArCH2Ar), 6.59 (d, 4J = 2.0 Hz, 2 H, ArH), 4.63
[s, 2 H, OCH2C(O)], 6.65 (d, 4J = 2.0 Hz, 2 H, ArH), 6.68 (d, 4J =
3
2.0 Hz, 2 H, ArH), 6.98 (s, 2 H, ArH), 6.99 (d, J = 8.2 Hz, 4 H,
HTol), 7.00 (d, 3J = 8.2 Hz, 2 H, HTol), 7.16 (d, 3J = 8.2 Hz, 4 H, HTol),
3
7.15 (s, 2 H, ArH), 7.24 (d, J = 8.2 Hz, 2 H, HTol), 8.01 (s, NH),
8.14 (s, NH), 8.25 (s, NH), 8.33 (s, NH). The intensity of NH pro-
tons is lower due to deuterium exchange.
13C{1H} NMR [100.6 MHz, DMSO-d6 + CD3CO2D (10%)]: d =
10.2 (CH3), 10.5 (CH3), 20.5 (TolCH3), 22.9 (CH2), 24.0
[C(O)CH3], 25.4 (CH2), 30.9 (CH2), 31.4 (CH2), 67.3 (OCH2), 70.8
(OCH2), 77.0 (OCH2), 77.3 (OCH2), 118.2 (CH), 118.3 (CH), 118.6
(CH), 119.7 (CH), 129.3 (CH), 129.4 (CH), 130.6 (C), 130.7 (C),
133.8 (C), 133.9 (C), 134.2 (C), 135.1 (C), 135.5 (C), 137.5 (C),
150.8 (C), 151.4 (C), 151.6 (C), 152.7 (C), 152.8 (C), 168.1 (C),
171.2 (C).
MS (ESI): m/z (%) = 1132.5 (100) [M + Na]+.
5-Acetamido-11,17,23-tris-[3-(4-methylphenyl)ureido]-
25,26,27-tripropoxy-28-(10-carboxydecyloxy)calix[4]arene
(14b)
Following the typical procedure for 14a using THF–MeOH (4:3) as
solvent, gave 14b in 98% yield as a white powder; mp >190–193 °C
(dec).
1H NMR (400 MHz, DMSO-d6): d = 1.00–0.94 (m, 9 H, CH3), 1.37–
1.28 (m, 12 H, CH2), 1.49 (m, 2 H, CH2), 1.89 [m, 11 H, CH2,
3
C(O)CH3], 2.19 [t, J = 7.3 Hz, 2 H, C(O)CH2], 2.22 (s, 9 H,
TolCH3), 3.11–3.06 (m, 4 H, ArCH2Ar), 3.83–3.73 (m, 8 H, OCH2),
4.33 (d, 2J = 12.7 Hz, 2 H, ArCH2Ar), 4.34 (d, 2J = 12.7 Hz, 2 H,
ArCH2Ar), 6.72 (s, 4J = 2.0 Hz, 2 H, ArH), 6.77 (s, 4J = 2.0 Hz, 2 H,
ArH), 6.83 (s, 2 H, ArH), 7.04–6.99 (m, 8 H, ArH, HTol), 7.21 (d,
3J = 8.3 Hz, 4 H, HTol), 7.27 (d, 3J = 8.3 Hz, 2 H, HTol), 8.10 (s, 2 H,
NH), 8.13 (s, 1 H, NH), 8.21 (s, 2 H, NH), 8.28 (s, 1 H, NH), 9.48
[s, 1 H, NHC(O)CH3], 11.95 (s, 1 H, COOH).
(16) Bogdan, A.; Vysotsky, M. O.; Böhmer, V. Collect. Czech.
13C{1H} NMR (100.6 MHz, DMSO-d6): d = 10.0 (CH3), 10.2
(CH3), 20.2 (TolCH3), 22.6 (CH2), 22.7 (CH2), 23.7 [C(O)CH3],
24.4 (CH2), 25.6 (CH2), 28.5 (CH2), 28.6 (CH2), 28.8 (CH2), 28.9
(CH2), 29.0 (CH2), 29.4 (CH2), 30.6 (CH2), 33.6 (CH2), 74.7
(OCH2), 76.2 (OCH2), 76.4 (OCH2), 117.9 (CH), 118.1 (CH), 119.0
(CH), 128.9 (CH), 129.0 (CH), 130.1 (C), 133.2 (C), 133.3 (C),
133.4 (C), 134.0 (C), 134.1 (C), 134.2 (C), 134.4 (C), 137.2 (C),
150.8 (C), 151.0 (C), 151.8 (C), 152.4 (C), 167.4 (C), 174.4 (C).
Chem. Commun. 2004, 69, 1009.
(17) X-ray crystallographic data for 4: C53H71NO8·C2H3N M =
891.16 g·mol–1, colorless block, size 0.52 × 0.41 × 0.26 mm3,
monoclinic, space group P21/n, a = 18.4285 (13), b = 24.673
(2), c = 23.6687 (17) Å, b = 101.889 (6), V = 10531.0(14) Å3,
T = –100 °C, Z = 8, rcalcd = 1.124 g·cm–3, m (Mo-Ka) = 0.074
mm–1, F(000) = 3856, 66424 reflections in h(–21/22), k(–29/
29), l(–28/26), measured in the range 2.56° ≤ Q ≤ 25.39°,
completeness Qmax = 98.3%, 19049 independent reflections,
Rint = 0.0889, 8537 reflections with Fo > 4s(Fo), 1229
parameters, 0 restraints, R1obs = 0.0676, wR2obs = 0.1603,
MS (ESI): m/z (%) = 1258.6 (100) [M + Na]+.
Synthesis 2008, No. 5, 754–762 © Thieme Stuttgart · New York

762
Y. Rudzevich et al.
PAPER
(19) (a) Böhmer, V.; Jung, K.; Schön, M.; Wolff, A. J. Org.
R1all = 0.1406, wR2all = 0.1890, GOOF = 0.850, largest
difference peak and hole: 0.928/–0.363 e·Å–3.
Chem. 1992, 57, 790. (b) Sansone, F.; Barboso, S.; Casnati,
A.; Fabbi, M.; Pochini, A.; Ugozzoli, F.; Ungaro, R. Eur. J.
Org. Chem. 1998, 897.
(18) X-ray crystallographic data for 6: C51H69NO5·2 C2H6OS,
M = 932.33 g·mol–1, colorless rod, size 0.27 × 0.14 × 0.13
mm3, triclinic, space group P–1, a = 12.3270 (8), b =
(20) Blessing, R. H. Acta Crystallogr., Sect. A 1995, 51, 33.
(21) Sheldrick, G. M. Acta Crystallogr., Sect. A 1990, 46, 467.
(22) SHELXL-97 (Release 97-2), Sheldrick, G. M., University of
Göttingen: Germany, 1997.
21.5880 (11), c = 22.6254 (12) Å, a = 65.959 (4), b = 83.687
(5), g = 80.551 (5)°, V = 5417.9 (5) Å3, T = –100 °C, Z = 4,
r
calcd = 1.143 g·cm–3, m (Mo-Ka) = 0.147 mm–1, F(000) =
2024, 52650 reflections in h(–14/12), k(–25/25), l(–26/26),
measured in the range 3.35° ≤ Q ≤ 25.03°, completeness
(23) CCDC 662358 (4) and CCDC 662359 (6) contain the
supplementary crystallographic data for this paper. These
data can be obtained free of charge via
Q
max = 99.4%, 19028 independent reflections, Rint = 0.0624,
12643 reflections with Fo > 4s(Fo), 1263 parameters, 60
restraints, R1obs = 0.0895, wR2obs = 0.2316, R1all = 0.1274,
wR2all = 0.2585, GOOF = 1.047, largest difference peak and
hole: 1.318/–1.408 e·Å–3.
www.ccdc.cam.ac.uk/conts/retrieving.html (or from the
Cambridge Crystallographic Data Centre, 12 Union Road,
Cambridge CB2 1EZ, UK; fax: +44 (1223)336033; email:
deposit@ccdc.cam.ac.uk).
Synthesis 2008, No. 5, 754–762 © Thieme Stuttgart · New York