Heterocalixarenes. Part 4 - Synthesis of oxocalix[1]heterocycle[2]-arenes: A unique H-bonding network in calix[1]benzimidazol-2-one[2]arene·1/2 H2O

Article abstract of DOI:10.1039/b000832j

The Friedel-Crafts aroylation of 2-methylanisole with 3-methylbenzoyl chloride followed by NBS bromination and cyclizations with 1,3-dihydrobenzimidazol-2-one, 1,3-dihydro-5,6-dinitrobenzimidazol-2-one, uracil, 6-methyluracil and quinazoline-2,4(1H, 3H)-dione provide respective oxocalix[1]heterocycle[2]arenes 5-9. The X-ray crystal structure (solid) and ¹H NMR spectral (solution) studies show them to have by and large inwardly flattened partial cone conformations which vary in torsion angles between the rings. The calix[1]benzimidazol-2-one[2]arene·1/2 H₂O complex shows a unique array of H-bonds in which three of the four CH and the imide oxygen of the benzimidazol-2-one unit, carbonyl oxygen and water molecule are involved in H-bonding with surrounding calixarene molecules. This heterocalixarene, in contrast to earlier reported benzimidazol-2-one-based calixarenes, does not show hetero-cyclic π-π stacking. The Friedel-Crafts aroylation of 2-methylanisole with 3-methylbenzoyl chloride followed by NBS bromination and cyclizations with 1,3-dihydrobenzimidazol-2-one, 1,3-dihydro-5,6-dinitrobenzimidazol-2-one, uracil, 6-methyluracil and quinazoline-2,4(1H, 3H)-dione provide respective oxocalix[1]heterocycle[2]arenes 5-9. The X-ray crystal structure (solid) and ¹H NMR spectral (solution) studies show them to have by and large inwardly flattened partial cone conformations which vary in torsion angles between the rings. The calix[1]benzimidazol-2-one[2]arene·1/2 H₂O complex shows a unique array of H-bonds in which three of the four CH and the imide oxygen of the benzimidazol-2-one unit, carbonyl oxygen and water molecule are involved in H-bonding with surrounding calixarene molecules. This heterocalixarene, in contrast to earlier reported benzimidazol-2-one-based calixarenes, does not show hetero-cyclic π-π stacking.

Full text of DOI:10.1039/b000832j

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Heterocalixarenes. Part 4. Synthesis of oxocalix[1]heterocycle[2]-
arenes: a unique H-bonding network in calix[1]benzimidazol-2-
1
2
one[2]areneؒ– H2O†
1
Subodh Kumar,* Geeta Hundal, Dharam Paul, Maninder Singh Hundal and Harjit Singh*
Department of Chemistry, Guru Nanak Dev University, Amritsar - 143 005, India.
Fax: (0183) 258820
Received (in Cambridge, UK) 31st January 2000, Accepted 2nd May 2000
Published on the Web 3rd July 2000
The Friedel–Crafts aroylation of 2-methylanisole with 3-methylbenzoyl chloride followed by NBS bromination and
cyclizations with 1,3-dihydrobenzimidazol-2-one, 1,3-dihydro-5,6-dinitrobenzimidazol-2-one, uracil, 6-methyluracil
and quinazoline-2,4(1H,3H)-dione provide respective oxocalix[1]heterocycle[2]arenes 5–9. The X-ray crystal
structure (solid) and 1H NMR spectral (solution) studies show them to have by and large inwardly flattened partial
cone conformations which vary in torsion angles between the rings. The calix[1]benzimidazol-2-one[2]areneؒ¹ H2O
¯
²
complex shows a unique array of H-bonds in which three of the four CH and the imide oxygen of the benzimidazol-
2-one unit, carbonyl oxygen and water molecule are involved in H-bonding with surrounding calixarene molecules.
This heterocalixarene, in contrast to earlier reported benzimidazol-2-one-based calixarenes, does not show hetero-
cyclic π–π stacking.
Calix[n]arenes – which structurally constitute a cyclic array of
1,3-phenylene rings joined by methylene bridges – adopt varied
conformations depending upon the number of 1,3-phenylene
rings2 and the nature of substituents present on these rings2/
methylene bridges.3 The tetra-O-substituted calix[4]arenes
have a rigid structure and may adopt cone, partial cone, 1,2-
alternate or 1,3-alternate conformations. The higher homo-
logues of calix[4]arenes, due to their increased structural
flexibility, display numerous conformations. The replacement
of arene ring(s) with heterocyclic ring(s) influences the π-electron
density in the cavities and also provides alternative sites for
binding.4
methylbenzoyl chloride 2 in dry chloroform in the presence
of AlCl3 (anhydrous) provides 3 (95%). The bromination of
3 with NBS in CCl4 provides the dibromide 4 (70%). The inter-
molecular cyclization of 4 with 1,3-dihydrobenzimidazol-2-one
under phase-transfer catalytic conditions provides mono-
oxoheterocalix[3]arene 5 (40%) (Scheme 1) and isomeric dioxo-
heterocalix[6]arene 10a or 10b (< 2%).
The reaction of 4 with 1,3-dihydro-5,6-dinitrobenzimidazol-
2-one provides only 6 (28%). The cyclocondensation of 4 with
uracil/6-methyluracil, due to non-equivalence of N-1 and N-3,
could form isomeric products 7/8 and 7a/8a. However, in each
1
case a single isomer (TLC, H NMR) was formed. So, NOE
The calixarenes with less than four rings have attracted scant
attention. The only known p-halogenocalix[3]arenes5 have been
assigned a cone conformation by 1H NMR and IR spectral data
but, due to the non-availability of any X-ray structure, it is
not confirmed. Recently, three-fold and two-fold symmetric
conformations of carbotrianions of calix[3]arenes6 have been
revealed. To the best of our knowledge, no other report on
calix[3]arenes is available in the literature. Now, in the present
investigation, a simple three-step methodology for the synthesis
of oxo-bridged calix[1]heterocycle[2]arenes (5–9), a previously
unknown class of heterocalix[3]arenes, is reported. The X-ray
crystal structures of heterocalix[3]arenes 5 and 7 show them
to have inwardly flattened partial cone conformations. The
calix[1]dihydrobenzimidazol-2-one[2]arene 5, which crystallizes
as a 2:1 complex with water, shows a unique array of H-bonds
in which three of the four CH and the imide oxygen of the
1,3-dihydrobenzimidazol-2-one unit, the carbonyl oxygen and
a water molecule are involved in H-bonds with surrounding
calixarene molecules.
experiments were performed to determine their structures. In
the NOE spectrum of 7, irradiation of the U-6H doublet
enhanced the intensities of one doublet (δ 4.59) of an AB quar-
tet (δ 4.59, 5.48) and of the U-5H doublet and OCH3 singlet.
This observation shows that N1-CH2 is placed close to the
OCH3 group. Therefore, the cyclization of 4 with uracil pro-
vides exclusively 7 and not the isomeric 7a. Structure 7 has been
confirmed by single-crystal X-ray structure analysis. In the
NOE spectrum of 8, irradiation of the U6-CH3 group enhanced
the intensity of U-5H (singlet) and one doublet (δ 4.89) of an
AB quartet (δ 4.89, 5.40). Irradiation of the proton C3-H
marked with an asterisk (structure 11) enhanced the intensity of
a second AB quartet (δ 5.20, 5.46). These results point to the
proximity between N-1 CH2 and OCH3 groups. So, the reaction
Results and discussion
Synthesis
The Friedel–Crafts aroylation of 2-methylanisole 1 with 3-
† 1H–1H COSY spectra of compounds 7–9 are available as supplemen-
tary data from BLDSC (SUPPL. NO. 57709, pp. 4) or the RSC
Library. See Instructions for Authors available via the RSC web page
(http://www.rsc.org/authors).
DOI: 10.1039/b000832j
J. Chem. Soc., Perkin Trans. 1, 2000, 2295–2301
This journal is © The Royal Society of Chemistry 2000
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Scheme 1
of 4 with 6-methyluracil provides exclusively one isomer 8,
out of the two possible isomers 8 and 8a.
In case of the condensation product of 4 and quinazoline-
2,4(1H,3H)-dione, the signals of various protons in the aro-
matic region are so closely placed that irradiation of a
selected signal in the NOE experiment is not possible. So, it was
not possible to experimentally define the structure but, in
analogy with 7 and 8, the structure 9 has been assigned to the
product.
Conformational analysis
The heterocalix[3]arenes can adopt either cone or partial cone
conformations. The inward or outward flattening of one of the
rings can lead to additional inwardly flattened or outwardly
flattened cone or partial cone conformations (Fig. 1). The
conformational analysis of these heterocalix[3]arenes has been
carried out by using X-ray (solid state), 1H NMR, 1H–1H
COSY (solution state) and force-field energy-minimization
studies. The heterocalixarenes 5–9 have two arylene rings as
a common structural feature and differ in the nature of the
heterocyclic rings which are invariably elaborate urea spacers,
and so can be collectively represented in structure 11.
Fig. 1 Iconographic representations of possible conformations in
calix[3]arenes.
(a) Solid phase: X-ray. The X-ray crystal structures of hetero-
calix[3]arenes 5 and 7 (Figs. 2 and 3) show them to attain by
and large similar conformations, which have been analysed
as inwardly flattened partial cone conformations. The small
differences in torsion angles (Fig. 4, Table 1) arising in 5 and
7 may be due to the presence of different heterocyclic rings,
and a water molecule in the case of 5.
Fig. 2 ORTEP view of heterocalix[3]arene 5. Thermal ellipsoids
are drawn with 50% probability and hydrogen atoms are drawn with
arbitrary small isotropic thermal parameters for the sake of clarity.
respect to the mean plane constituted by bridging carbons C1,
C8 and C15, the heterocyclic rings are nearly perpendicular
[81.1(1)Њ in 5, 108.7(1)Њ in 7], the phenylene rings ‘B’ are in an
The torsion angles about C1, C8 and C15 vary as Ϫ ϩ, ϩ ϩ,
Ϫ Ϫ, in both the heterocalix[3]arenes (Table 1). In 5 and 7 with
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Table 1 Important torsion angles (Њ) in heterocalixarenes 5 and 7
Table 2 The four distinct H-bonding distances (Å) and angles (Њ) in 5
5
7
X ؒ ؒ ؒ O
Å
H ؒ ؒ ؒ O
Å
∠X–H–O
C7–C2–C1–N1
C2–C1–N1–C17
C14–C13–C15–N2
C13–C15–N2–C17
C7–C6–C8–C9
Ϫ53.6(3)
81.0(3)
Ϫ17.5(4)
Ϫ59.7(3)
25.2(4)
Ϫ66.3(3)
85.4(3)
Ϫ14.4(4)
Ϫ59.7(3)
28.7(3)
O4 ؒ ؒ ؒ O3Ј
C23 ؒ ؒ ؒ O4ii
C21 ؒ ؒ ؒ O1iv
C22 ؒ ؒ ؒ O1v
2.85(1)
3.47(1)
3.42(1)
3.35(1)
H41 ؒ ؒ ؒ O3i
H23 ؒ ؒ ؒ O4ii
H21 ؒ ؒ ؒ O1iv
H22 ؒ ؒ ؒ O1v
1.93(4)
2.5(1)
2.5(5)
2.5(4)
174(1)
173(3)
155(3)
145(3)
3
1
–
–
i = Ϫx, ϩy, Ϫz ϩ 2; ii = x, y ϩ 1, z; iv = x, Ϫy ϩ 1, z ϩ 2; v =
C6–C8–C9–C14
23.3(4)
25.7(4)
1
1
1
–
–
–
Ϫx ϩ 2, Ϫy ϩ 2, z ϩ 2.
Fig. 3 ORTEP view of heterocalix[3]arene 7. Thermal ellipsoids
are drawn with 50% probability and hydrogen atoms are drawn with
arbitrary small isotropic thermal parameters for the sake of clarity.
Fig. 5 Diagram showing H-bonding of H2O with four molecules of
heterocalix[3]arene 5 in tetrahedral geometry.
The heterocalixarenes 5 and 7 show quite different crystal
packings. 5 Crystallizes as 5ؒ¹ H2O complex and shows a
¯
²
strong H-bonding network. Each molecule acts three times as
an acceptor and three times as a donor, making six contacts
per molecule with four distinct distances (Table 2). As a result
each molecule of 5 is connected to five other symmetry-related
molecules through CH ؒ ؒ ؒ O interactions, and with three
symmetry-related molecules through H2O H-bonding inter-
actions. Each water molecule is strongly H-bonded to four
molecules of 5 placed in a tetrahedral geometry (Fig. 5). Water
behaves both as H-bond donor and acceptor. Water O4 donates
through both its hydrogens, which are bonded to O3 of
two symmetry-related molecules. Water behaves as an H-bond
acceptor through 23-H ؒ ؒ ؒ O4 (Table 2). The oxygen of oxo
bridge O1 is also involved in CH ؒ ؒ ؒ O-type H-bonding inter-
actions with an aromatic CH of the benzimidazol-2-one unit
of two adjacent molecules of 5 (Table 2). The packing of 5
(Fig. 6) shows stacking of the molecule down the ‘b’-axis. This
packing gives rise to face-to-face π–π interactions8 [4.0(1) Å]
between the rings ‘B’ of the two heterocalix[3]arene molecules
related by a glide plane perpendicular to the ‘b’-axis. In con-
trast to benzimidazol-2-one-based calix[8/9]arenes,4c,4d where
side-on-side stacking of heterocyclic units is an important
motif contributing to crystal formation, here in calix[1]-1,3-
Fig. 4 Superimposition of X-ray structures of 5 (bold) and 7 (dotted).
anti position [141.7(1)Њ in 5, 134.8(1)Њ in 7] and phenylene rings
‘A’ are in nearly a gauche [38.5(1)Њ in 5, 42.9(1)Њ in 7] conform-
ation. The phenylene rings ‘A’ and ‘B’ (see structure 11)
are placed at an angle of 79.6(1)Њ, 65.29(1)Њ in 5 and 96.8(1)Њ,
56.6(1)Њ in 7 with respect to the heterocyclic rings, but are in
nearly a gauche [55.4(1)Њ in 5, 40.8(1)Њ in 7] conformation with
respect to each other. Consequently, 7-H and 14-H are oriented
above and below the plane of the bridging carbons, respectively.
The 7-H lies in the direction of O3, and 14-H faces the other
side, giving rise to an inwardly flattened partial cone con-
formation, where ring ‘B’ is placed in an inwardly flattened
conformation. It may be seen that, in 5 and 7, 7-H shows
unique short intramolecular contacts with O3 and that 14-H
lies under the influence of the π-cloud of the respective hetero-
cyclic rings. There is a strong ArCH ؒ ؒ ؒ π interaction between
14-H ؒ ؒ ؒ 1,3-dihydrobenzimidazol-2-one ring [2.7(1) Å, 122(1)Њ]
in 5. These distances and angles are found to be quite com-
parable with those reported earlier.4d,7 A similar CH ؒ ؒ ؒ π
interaction in 7 [ArH ؒ ؒ ؒ π = 2.9(1) Å] may be considered, but
is quite weak.
dihydrobenzimidazol-2-one[2]arenes such heterocyclic
π
stacking is not observed.
The packing of 7 (Fig. 7) shows C-10 ؒ ؒ ؒ O1vi H-bond
interactions between two symmetry-related molecules of 7
[C10 ؒ ؒ ؒ O1vi 3.25(1) Å, 10-H ؒ ؒ ؒ O1vi 2.4(1) Å, 153(1)Њ, vi =
Ϫx ϩ 1, Ϫy ϩ 2, Ϫz ϩ 1], giving rise to dimers. This packing
results in a strong face-to-face π–π interaction8 [3.5(1) Å]
between two symmetry-related rings ‘B’ of 7, down the ‘b’ axis.
1
(b) Solution phase: H NMR. The rationalization of multi-
plicities and chemical shifts of various proton signals in the 1H
NMR spectra, and comparison with their acyclic precursors,
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1
–
Fig. 6 Packing diagram of 5ؒ2 H2O showing H-bonding network.
Fig. 7 Packing diagram of 7 showing H-bonding and π–π interactions.
provides a useful tool for assigning the geometries of calix-
downfield signal at δ 7.68. The doublets at δ 7.53, 7.68 also show
arenes. The heterocalix[3]arenes 5–9, show well defined 1H NMR
spectra but the presence of a number of doublets makes it
impossible to assign chemical shifts to various protons. So, in
order to assign the chemical shifts of the various protons, the
1H–1H COSY spectra of heterocalix[3]arenes 5–9 have been
recorded.
cross-peaks at δ 7.17 (s, C7-H) due to meta-couplings. The
double doublet of C10-H at δ 7.87 (J1 8.6 Hz, J2 2.2 Hz) shows
two cross-peaks, at δ 6.94 (d, J 8.6 Hz, C11-H) and 6.62 (d, J 2.2
Hz, C14-H). This assignment is based on the doublet at δ 6.94,
which could easily be assigned to C11-H, placed ortho to the
OMe unit. 1H NMR spectra of the heterocalixarenes 6–9 simi-
larly exhibit NCH2 units as AB quartets and well resolved aro-
matic H signals, which could be assigned to specific protons
The 1H NMR spectrum of 5 exhibits four doublets (two
pairs) with geminal coupling (δ 4.98, 5.34; 4.82, 5.53; J =
16.6 Hz), due to two NCH2 units and well defined but com-
1
from their H–1H COSY spectra (see supplementary data for
1
plex multiplets in the aromatic region. In the H–1H COSY
spectra of compounds 7–9).
1
spectrum of 5 (Fig. 8), the triplet (δ 7.37 (of C4-H shows cross-
peaks at δ 7.53 (d, C3-H/C5-H) and 7.68 (d, C5-H/C3-H). Since
C5-H is ortho to the carbonyl group, it could be assigned the
The comparison of H NMR chemical shifts of heterocalix-
[3]arenes 5–9 with 4 shows that the signals due to C7-H and
C14-H of rings ‘A’ and ‘B’, respectively, depending upon the
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Fig. 8 1H–1H COSY spectrum of heterocalix[3]arene 5.
Table 3 Change in chemical shifts (∆ δ) of C7-H and C14-H in 5–9
in comparison with 4
spectrum and ‘ab’ corresponds to quaternary C signals, which
are absent in DEPT-135 but are observed in the normal 13C
spectrum.
Heterocalix[3]arene
Synthesis of benzophenone derivative 3
5
6
7
8
9
To a suspension of AlCl3 (anhydrous) (13.5 g, 0.1 mol) in dry
chloroform (100 ml) was added 3-methylbenzoyl chloride 2
(15.0 g, 0.095 mol) with stirring during 5 min. The stirring
was continued to dissolve AlCl3 completely and the temper-
ature of the reaction mixture was lowered to 5 ЊC by immers-
ing the flask in an ice-bath. A solution of 2-methylanisole 1
(14.6 g, 0.12 mol) in dry chloroform (50 ml) was added
dropwise during 30 min and stirring was continued at room
temperature for 1 h. The reaction mixture was cooled to 0 ЊC
and treated with methanol and then with water. It was
extracted with chloroform, the organic layer was dried with
Na2SO4 (anhyd.), and solvents were removed and the residue
was fractionally distilled under vacuum to give pure 3 (95%),
C7-H
C14-H
Ϫ0.62
Ϫ1.25
Ϫ1.13
Ϫ1.08
Ϫ0.42
Ϫ0.83
Ϫ0.25
Ϫ0.84
Ϫ0.43
Ϫ0.43
nature of the heterocyclic moiety, are shifted upfield by 0.25–
1.13 and 0.43–1.25 ppm (Table 3). The other signals remain
by and large unaffected. Therefore, C7-H and C14-H protons
have been placed in geometrical positions where they either
interact with the imide O or face the aryl rings. Since these
heterocalix[3]arenes exhibit AB quartets due to NCH2 protons,
these are considered to have rigid structures and might
have similar conformations in both the solid and solution
phases. In analogy with X-ray crystal-structure analysis, C14-H
in 5 is placed close to the π-cloud of the heterocyclic ring
and is shifted more upfield than it is in 7. Similarly, C7-H
forms a better contact with imide C᎐O in 5 and is shifted more
upfield than is observed in 7. So, the H NMR spectra show
that the heterocalix[3]arenes 5–9 have, by and large, inwardly
flattened partial cone conformations, but, depending upon the
nature of heterocyclic ring, the torsion angles between the rings
vary.
1
bp 194–198 ЊC (20 mmHg), mp 64–66 ЊC; m/z 240 (Mϩ); H
NMR (CDCl3) δ 2.26 (3H, s, CH3), 2.42 (3H, s, CH3), 3.91 (3H,
s, OCH3), 6.86 (1H, d, J 9.0 Hz, ArH), 7.34–7.69 (6H, m,
6 × ArH); 13C NMR (normal/DEPT-135) (CDCl3) δC 15.65
(ϩve, CH3), 20.72 (ϩve, CH3), 54.84 (ϩve, OCH3), 106.44 (ϩve,
ArCH), 126.04 (ab, ArC), 126.39 (ϩve, ArCH), 127.41
(ϩve, ArCH), 129.19 (ab, ArC), 129.56 (ϩve, ARCH), 130.06
(ϩve, ArCH), 131.96 (ϩve, ArCH), 137.36 (ab, ArC), 137.99
᎐
1
(ab, ArCH), 160.91 (ab, ArC), 195.08 (ab, C᎐O); νmax(KBr)/
᎐
Therefore,
a simple three-step methodology involving
cmϪ1 1667 (Calc. for C16H16O2: C, 80.00; H, 6.67. Found: C,
79.3; H, 6.9%).
Friedel–Crafts aroylation as the key step provides mono-oxo-
calix[1]heterocycle[2]arenes. The calix[1]dihydrobenzimidazol-
2-one[2]areneؒ¹ H2O complex shows a strong H-bonding
¯
²
Synthesis of dibromide 4
network but, in contrast to earlier reported benzimidazol-2-
one-based calixarenes, does not show heterocyclic π-stacking.
A solution of ketone 3 (24.0 g, 0.1 mol) in CCl4 (200 ml) con-
taining a suspension of NBS (37.2 g, 0.21 mol) and benzoyl
peroxide (100 mg) was refluxed for 4 h. The solid formed was
filtered off and the solvent was removed under vacuum. The
solid residue was crystallized from methanol–dichloromethane
mixture (70%), mp 100–102 ЊC; m/z 396, 398, 400 (1:2:1, Mϩ);
Experimental
For experimental details, see ref. 9. In 13C NMR spectral
data, the ϩve and Ϫve signals correspond to the DEPT-135
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1H NMR (CDCl3) δ 4.00 (3H, s, OCH3), 4.54 (2H, s, CH2),
4.57 (2H, s, CH2), 6.97 (1H, d, J 8.6 Hz, ArH), 7.47 (1H, t, J 6.8
Hz, ArH), 7.60–7.70 (2H, m, 2 × ArH), 7.79 (1H, s, ArH), 7.81
(1H, dd, J1 8.6 Hz, J2 2.0 Hz, ArH), 7.87 (1H, d, J 2.0 Hz, ArH);
13C NMR (normal/DEPT-135) (CDCl3) δC 27.81 (Ϫve, CH2),
32.48 (Ϫve, CH2), 55.93 (ϩve, OCH3), 110.34 (ϩve, ArCH),
126.30 (ab, ArC), 128.69 (ϩve, ArCH), 129.49 (ϩve, ArCH),
129.67 (ab, ArC), 130.07 (ϩve, ArCH), 133.41 (ϩve, ArCH),
133.02 (ϩve, ArCH), 133.06 (ϩve, ArCH), 138.05 (ab, ArC),
J 7.8 Hz, ArH), 7.36 (2H, d, J 7.8 Hz, ArH), 7.50 (2H, dd, J1 7.8
Hz, J2 1.8 Hz, ArH), 7.58 (2H, s, ArH), 7.66 (2H, s, ArH); 13
C
NMR (normal/DEPT-135) (CDCl3) δC 40.71 (Ϫve, NCH2),
44.60 (Ϫve, NCH2), 55.50 (ϩve, OCH3), 110.00 (ϩve, ArCH),
112.04 (ϩve, ArCH), 121.32 (ϩve, ArCH), 121.77 (ϩve,
ArCH), 123.70 (ϩve, ArCH), 128.26 (ϩve, ArCH), 128.67 (ab,
ArC), 128.78 (ϩve, ArCH), 129.03 (ab, ArC), 129.21 (ab, ArC),
129.53 (ϩve, ArCH), 130.74 (ϩve, ArCH), 131.09 (ϩve,
ArCH), 132.58 (ϩve, ArCH), 135.91 (ab, ArC), 137.18 (ab,
138.40 (ab, ArC), 160.96 (ab, ArC), 194.13 (ab, C᎐O);
ArC), 154.05 (ab, C᎐O), 155.54 (ab, C᎐O), 161.10 (ab, ArC),
᎐
᎐ ᎐
νmax(KBr)/cmϪ1 1660 (Calc. for C16H14Br2O2: C, 48.24; H, 3.52.
192.91 (ab, C᎐O); νmax(KBr)/cmϪ1 1669, 1718.
᎐
Found: C, 48.8; H, 4.0%).
Compound 7. (60%), mp 230 ЊC (from MeOH ϩ CHCl3);
General procedure for the synthesis of 5–9
1
m/z 348 (Mϩ); H NMR (CDCl3) δ 3.97 (3H, s, OCH3), 4.59,
A suspension of dibromide 4 (3.98 g, 0.01 mol) and 1,3-
dihydrobenzimidazol-2-one (1.34 g, 0.01 mol) in acetonitrile
(700 ml) containing K2CO3 (12 g) and tetrabutylammonium
hydrogen sulfate (TBAؒHSO4) (50 mg) was heated to reflux
and the progress of reaction was monitored by TLC. After the
completion of reaction, suspended solid was filtered off and
the filtrate was concentrated under vacuum and the residue
was subjected to column chromatography to afford pure
product 5. Similarly, the reactions of dibromide 4 with 1,3-
dihydro-5,6-dinitrobenzimidazol-2-one,10 uracil, 6-methyluracil
and quinazoline-2,4(1H,3H)-dione gave the respective calix-
arenes 6–9.
5.48 (2H, two doublets, J 16.0 Hz, N3-CH2), 5.16, 5.49 (2H,
two doublets, J 14.2 Hz, N1-CH2), 5.66 (1H, d, J 7.8 Hz,
U5Ј-H), 7.00 (1H, d, J 8.6 Hz, C11-H), 7.04 (1H, br s, C14-
H), 7.11 (1H, d, J 7.8 Hz, U6Ј-H), 7.37 (1H, br s, C7-H),
7.44 (1H, t, J 7.6 Hz, C4-H), 7.59 (1H, d, J 7.6 Hz, C3-H),
7.80 (1H, d, J 7.6 Hz, C5-H), 7.96 (1H, dd, J1 8.4 Hz, J2 2.0
Hz, C10-H); 13C NMR (normal/DEPT-135) (CDCl3) δ 44.37
(Ϫve, CH2), 49.58 (Ϫve, CH2), 55.87 (ϩve, OCH3), 102.56
(ϩve, U5-CH), 110.53 (ϩve, ArCH), 122.87 (ab, ArC), 127.75
(ϩve, ArCH), 128.65 (ab, ArCH), 130.47 (ab, ArC), 130.79
(ϩve, ArCH), 131.87 (ϩve, ArCH), 132.54 (ϩve, ArCH),
133.99 (ϩve, ArCH), 136.74 (ab, ArC), 137.76 (ab, ArC),
142.94 (ϩve, U6-CH), 152.60 (ab, ArC), 159.43 (ab, C᎐O),
᎐
162.29 (ab, C᎐O), 194.14 (ab, C᎐O); νmax(KBr)/cmϪ1 1660,
1725 (Calc. for C20H16N2O4: C, 68.69; H, 4.60; N, 8.05.
Found: C, 69.0; H, 4.76; N, 7.5%).
Compound 5. (40%), mp 201–203 ЊC (from MeOH ϩ CHCl3);
᎐
᎐
1
m/z 370 (Mϩ); H NMR (CDCl3) δ 4.01 (3H, s, OCH3), 4.82,
5.53 (2H, two doublets, J 16.6 Hz, NCH2), 4.98, 5.34 (2H, two
doublets, J 16.6 Hz, NCH2), 6.62 (1H, s, C14-H), 6.94 (1H, d,
J 8.6 Hz, C11-H), 6.96 (4H, br s, benzim, ArH), 7.17 (1H, s,
C7-H), 7.37 (1H, t, J 6.6 Hz, C4-H), 7.53 (1H, d, J 7.6 Hz,
C3-H), 7.68 (1H, d, J 7.6 Hz, C5-H), 7.87 (1H, dd, J1 8.6 Hz,
J2 2.2 Hz, C10-H); 13C NMR (normal/DEPT-135) (CDCl3)
δC 40.51 (Ϫve, CH2), 46.27 (Ϫve, CH2), 55.76 (ϩve, OCH3),
108.94 (ϩve, ArCH), 109.46 (ϩve, ArCH), 110.22 (ϩve,
ArCH), 121.90 (ϩve, ArCH), 122.09 (ϩve, ArCH), 123.78
(ab, ArC), 127.79 (ϩve, ArCH), 128.16 (ϩve, ArCH), 129.51
(ab, ArC), 130.18 (ϩve, ArCH), 130.96 (ab, ArC), 131.16
(ϩve, ArCH), 133.45 (ϩve, ArCH), 134.82 (ϩve, ArCH),
136.70 (ab, ArC), 137.64 (ab, ArC), 158.11 (ab, C), 160.45
Compound 8. (65%), mp 242 ЊC (from MeOH ϩ CHCl3);
m/z 362 (Mϩ); 1H NMR (CDCl3) δ 2.21 (3H, s, U6Ј-CH3), 3.98
(3H, s, OCH3), 4.89, 5.40 (2H, two doublets, J 16.6 Hz, N3-
CH2), 5.20, 5.46 (2H, two doublets, J 14.0 Hz, N1-CH2), 5.54
(1H, s, U5Ј-H), 7.01 (1H, d, J 8.8 Hz, C11-H), 7.03 (1H, s,
C14-H), 7.44 (1H, t, J 7.6 Hz, C4-H), 7.54 (1H, s, C7-H),
7.60 (1H, d, J 7.6 Hz, C3-H), 7.80 (1H, d, J 7.6 Hz, C5-H),
8.00 (1H, dd, J1 8.6 Hz, J2 1.6 Hz, C10-H); 13C NMR
(CDCl3) δC 19.87 (ϩve, CH3), 44.12 (Ϫve, NCH2), 44.48
(Ϫve, NCH2), 55.71 (ϩve, OCH3), 102.23 (ϩve, U5-CH),
110.47 (ϩve, ArCH), 122.52 (ab, ArC), 127.72 (ϩve, ArCH),
128.51 (ϩve, ArCH), 130.05 (ab, ArC), 130.53 (ϩve, ArCH),
131.94 (ϩve, ArCH), 132.81 (ϩve, ArCH), 133.88 (ϩve,
ArCH), 136.90 (ab, ArC), 137.49 (ab, ArC), 151.53 (ab, ArC),
(ab, C), 193.55 (ab, C᎐O); νmax(KBr)/cmϪ1 1656, 1678 (Calc.
᎐
for C23H18N2O3: C, 74.59; H, 4.86; N, 7.56. Found: C, 74.1;
H, 4.2; N, 8.0%).
153.31 (ab, ArC), 159.44 (ab, C᎐O), 161.239 (ab, C᎐O),
᎐
᎐
Compound 6. (28%), mp 296–298 ЊC (from MeOH ϩ CHCl3);
193.80 (ab, C᎐O); νmax(KBr)/cmϪ1 1658, 1716 (Calc. for
᎐
1
m/z 460 (Mϩ); H NMR (CDCl3) δ 4.13 (3H, s, OCH3), 5.15,
C21H18N2O4: C, 69.61; H, 4.97; N, 7.73. Found: C, 69.4; H,
4.6; N, 7.5%).
5.62 (2H, two doublets, J 16.6 Hz, NCH2), 5.24, 5.49 (2H, two
doublets, J 16.6 Hz, NCH2), 6.66 (1H, br s, C7-H), 6.79 (1H, br
s, C14-H), 7.09 (1H, d, J 8.6 Hz, C11-H), 7.57 (1H, t, J 7.6 Hz,
C4-H), 7.66 (1H, d, J 7.6 Hz, benzim, ArH), 7.70 (1H, d, J 7.6
Hz, C3-H), 7.72 (1H, s, benzim. ArH), 7.86 (1H, d, J 7.6 Hz,
C5-H), 7.98 (1H, dd, J1 8.6 Hz, J2 2.0 Hz, C10-H); 13C NMR
(normal/DEPT-135) (CDCl3) δC 41.52 (Ϫve, CH2), 47.54 (Ϫve,
CH2), 56.21 (ϩve, OCH3), 106.33 (ϩve, ArCH), 107.70 (ϩve,
ArCH), 111.18 (ϩve, ArCH), 122.61 (ab, ArC), 129.00 (ϩve,
ArCH), 129.43 (ϩve, ArCH), 132.14 (ϩve, ArCH), 132.33
(ϩve, ArCH), 132.61 (ab, ArC), 132.79 (ϩve, ArCH), 134.69
(ab, ArC), 135.63 (ϩve, ArCH), 137.22 (ab, ArC), 138.92
(ab, ArC), 139.11 (ab, ArC), 158.33 (ab, C), 161.15 (ab, C),
Compound 9. (42%), mp 222 ЊC (from MeOH ϩ CHCl3);
1
m/z 398 (Mϩ); H NMR (CDCl3) δ 4.01 (3H, s, OCH3), 5.25,
5.80 (2H, two doublets, J 14.6 Hz, NCH2), 5.30, 5.65
(2H, two doublets, J 16.2 Hz, NCH2), 6.96 (1H, d, J 8.6 Hz,
C11-H), 7.22 (1H, t, J 7.4 Hz, quinaz. 7Ј-H), 7.36 (2H, br s, C7-,
C14-H), 7.46 (1H, t, J 7.4 Hz, C4-H), 7.48 (1H, d, J 7.8 Hz,
quinaz. 8Ј-H), 7.58–7.66 (2H, m, C3- and quinaz. 6Ј-H), 7.78
(1H, d, J 7.6 Hz, C5-H), 7.93 (1H, dd, J1 8.4 Hz, J2 2.2 Hz,
C10-H), 8.18 (1H, dd, J1 7.8 Hz, J2 1.2 Hz, quinaz. 5Ј-H); 13C
NMR (normal/DEPT-135) (CDCl3) δC 42.88 (Ϫve, NCH2),
45.96 (Ϫve, NCH2), 55.76 (ϩve, OCH3), 111.07 (ϩve, ArCH),
114.43 (ϩve, ArCH), 114.92 (ab, ArC), 124.92 (ϩve, ArCH),
128.64 (ϩve, ArCH), 128.80 (ab, ArC), 129.24 (ϩve, ArCH),
129.45 (ϩve, ArCH), 131.98 (ϩve, ArCH), 133.24 (ϩve,
ArCH), 135.46 (ab, ArC), 136.20 (ϩve, ArCH), 136.61
(ϩve, ArCH), 136.76 (ϩve, ArCH), 139.22 (ab, ArC), 152.81
196.77 (ab, C᎐O); νmax(KBr)/cmϪ1 1661, 1730 (Calc. for
᎐
C23H16N4O7: C, 60.00; H, 3.48; N, 12.17. Found: C, 60.1; H, 3.2;
N, 11.8%).
Compound 10. (< 2%), mp 279–283 ЊC (from CHCl3); m/z 740
1
(Mϩ); H NMR (CDCl3) δ 4.67 (6H, s, 2 × OCH3), 5.08 (4H,
s, NCH2), 5.16 (4H, s, NCH2), 6.53 (4H, d, J 8.0 Hz, ArH),
6.79–6.93 (4H, m, ArH), 6.97–7.24 (4H, m, ArH), 7.26 (2H, d,
(ab, ArC), 161.63 (ab, C᎐O), 163.40 (ab, C᎐O), 199.15 (ab,
᎐ ᎐
C᎐O); νmax(KBr)/cmϪ1 1662 (C᎐O), 1716 (C᎐O) (Calc. for
᎐
᎐
᎐
2300
J. Chem. Soc., Perkin Trans. 1, 2000, 2295–2301

View Article Online
Table 4 Crystal data collection and refinement parameters for hetero-
calix[3]arenes 5 and 7
References
1 (a) Part 1. S. Kumar, G. Hundal, D. Paul, M. S. Hundal and
H. Singh, J. Org. Chem., 1999, 64, 7717; (b) Part 2. S. Kumar,
D. Paul, H. Singh, J. Inclusion Phenom. Macrocyclic Chem., 2000,
37, 371; (c) Part 3. S. Kumar, G. Hundal, D. Paul, M. S. Hundal and
H. Singh, J. Chem. Soc., Perkin Trans. 1, 2000, 1037.
1
–
5ؒ2 H2O
7
1
–
Empirical formula
C23H18N2O3ؒ2 H2O C20H16N2O4
M
379.40
348.35
2 (a) C. D. Gutsche, Calixarenes Revisited, Monographs in Supra-
molecular Chemistry, ed. J. F. Stoddart, The Royal Society of
Chemistry, 1998, vol. 6; (b) C. D. Gutsche, Calixarenes, Monographs
in Supramolecular Chemistry, ed. J. F. Stoddart, The Royal Society
of Chemistry, 1989, vol. 1; (c) J. Vicens and V. Böhmer, Calixarenes:
A Versatile Class of Macrocyclic Compounds, ed. J. E. D. Davies,
Kluwer, Dordrecht, 1990; (d) V. Böhmer, Angew. Chem., Int. Ed.
Engl., 1995, 34, 713; (e) S. Shinkai, Tetrahedron, 1993, 49, 8933;
( f ) A. Ikeda and S. Shinkai, Chem. Rev., 1997, 97, 1713.
3 (a) S. Sartori, R. Maggi, F. Bigi, A. Arduini, A. Pastorio and
C. Porta, J. Chem. Soc., Perkin Trans. 1, 1994, 1657; (b) S. E. Biali,
V. B öhmer, S. Cohen, G. Ferguson, C. Grüttner, F. Grynszpan,
E. F. Paulus, I. Thondorf and W. Vogt, J. Am. Chem. Soc., 1996, 118,
12938; (c) M. Bergamaschi, F. Bigi, M. Lanfranchi, R. Maggi,
A. Postorio, M. A. Pellinghelli, F. Peri, C. Porta and G. Sartori,
Tetrahedron, 1997, 53, 13037; (d) K. Ro, S. Izawa, T. Ohba, Y. Ohba
and T. Sone, Tetrahedron Lett., 1996, 37, 5959.
Crystal system
Space group
Orthorhombic
Pbcn
25.868(2)
7.826(1)
18.105(2)
Monoclinic
P21/n
a/Å
b/Å
c/Å
β/Њ
12.259(2)
8.865(1)
15.943(2)
110.46(1)
1623.3(4)
4
V/ÅϪ3
Z
3665.2(7)
8
No. of measured/unique reflections 3233/3232
No. of observed reflections
[Io у 2σ(Io)]
2178/2036
2221
0.0473
1513
0.0423
Residual R (observed data)
C24H18N2O4: C, 72.36; H, 4.52; N, 7.04. Found: C, 71.7; H,
4.8; N, 7.5%).
4 (a) P. A. Gale, J. L. Sessler and V. Cral, Chem. Commun., 1998, 1;
(b) S. Shinoda, M. Todokoro, H. Tsukube and R. Arakawa, Chem.
Commun., 1998, 181; (c) E. Weber, J. Trepte, K. Gloe, M. Piel,
M. Czugler, V. C. Kravtsov, Y. A. Simonov, J. Lipkowski and
E. V. Ganin, J. Chem. Soc., Perkin Trans. 2, 1996, 2359; (d) J. Trepte,
M. Czugler, K. Gloe and E. Weber, Chem. Commun., 1997, 1461;
(e) B. Turner, M. Botoshansky and Y. Eichen, Angew. Chem., Int.
Ed., 1998, 37, 2475; ( f ) G. R. Newkome, Y. J. Joo and F. R. Franczek,
J. Chem. Soc., Chem. Commun., 1987, 845; (g) J. A. E. Pratt and
I. O. Sutherland, J. Chem. Soc., Perkin Trans. 1, 1988, 13; (h) P. R.
Dave, G. Doyle, T. Axenrod, H. Yazdekhasti and H. L. Ammon,
J. Org. Chem., 1995, 60, 6946; (i) P. R. Dave, G. Doyle, T. Axenrod,
H. Yazdekhasti and H. L. Ammon, Tetrahedron Lett., 1992, 33,
1021.
5 A. A. Moshfegh, E. Beladi, l. Radnia, A. S. Hosseini, S. Tofigh and
G. H. Hakimelahi, Helv. Chim. Acta, 1982, 65, 1264.
6 A. Rajca, S. Rajca and S. R. Desai, J. Am. Chem. Soc., 1995, 117,
806.
7 (a) J. D. Chaney, C. R. Goss, K. Folting, B. D. Santarsiero and
M. D. Hollingworth, J. Am. Chem. Soc., 1996, 118, 9432; (b) H. C.
Weiss, D. Blaser, R. Boese, B. M. Doughan and M. M. Haley,
Chem. Commun., 1997, 1703; (c) F. H. Allen, V. J. Hoy, J. A. K.
Howard, V. R. Thalladi, G. R. Desiraju, C. C. Wilson and
G. J. McIntyre, J. Am. Chem. Soc., 1997, 119, 3477.
X-Ray crystal structure analysis of heterocalix[3]arenes 5
and 7‡
The crystals of 5 and 7 suitable for X-ray diffraction work were
obtained by recrystallization from chloroform–methanol
(1:1). All intensity data measurements were carried out on a
Siemens P4 four-circle diffractometer with graphite mono-
chromatic Mo-Kα radiation (λ = 0.71069 Å) at room tem-
perature up to θmax = 25 ЊC. Both structures were solved
and refined using SHELXTL software11 package on a Siemens
Nixdorf computer. The data were corrected for Lorentz and
polarization effects but not for absorption effects. The struc-
tures were solved by direct methods. Full matrix least-squares
refinement was employed with anisotropic thermal parameters
for the non-hydrogen atoms. The hydrogen atoms attached to
the water molecules were located by difference Fourier synthesis
and the rest were fixed geometrically. The crystal data and
parameters for data collection and refinement are summarized
in Table 4.
8 D. B. Ambilino and J. F. Stoddart, Chem. Rev., 1995, 95,
2725.
9 S. Kumar, M. S. Hundal, G. Hundal, P. Singh, V. Bhalla and
H. Singh, J. Chem. Soc., Perkin Trans. 2, 1998, 925.
‡ CCDC reference number 207/429. See http://www.rsc.org/suppdata/
p1/b0/b000832j/ for crystallographic files in .cif format.
10 L. S. Efros and A. V. El’stov, Zh. Ova. Veng. Khim., 1957, 27, 127
(Chem. Abstr., 1957, 51, 12882h).
11 G. M. Sheldrick, SHELXTL-PC Version 5.03, Siemens Analytical
Instruments Inc., Madison, WI, 1995.
Acknowledgements
We thank UGC and DST, New Delhi for financial assistance.
J. Chem. Soc., Perkin Trans. 1, 2000, 2295–2301
2301