Liquid crystalline macrocycles containing phenylpyrimidine units

Article abstract of DOI:10.1039/b210271d

Several different macrocyclic liquid crystals consisting of two calamitic 2-phenylpyrimidine or 5-phenylpyrimidine units connected at both ends by polyether or alkyl chains have been synthesised by macrocyclisation reactions under high dilution conditions. The nature of the rigid core has a strong impact on the liquid crystalline phases formed. All 2-phenylpyrimidine paracyclophanes show nematic phases, whereas for the series of the 5-phenylpyrimidine derivatives smectic A-phases are exclusively formed. This behaviour is related to conventional calamitic phenylpyrimidine liquid crystals, but the mesophases are strongly stabilised in the macrocycles. An exchange of polyether chains by alkyl chains leads to significant mesophase stabilisation, whereas increasing the spacer length reduces mesophase stability. Pre-organization of the calamitic cores and micro-segregation of chemically distinct molecular parts are discussed as reasons for the observed effects of molecular structure on the mesophase behaviour of these compounds.

Full text of DOI:10.1039/b210271d

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Liquid crystalline macrocycles containing phenylpyrimidine units{
Bernhard Neumann,a{ Torsten Hegmann,a§ Christoph Wagner,b Peter R. Ashton,c
Raik Wolfd} and Carsten Tschierske*a
aInstitute of Organic Chemistry, Martin-Luther-University Halle-Wittenberg, Kurt-Mothes-
Str. 2, 06120 Halle, Germany. E-mail: Tschierske@Chemie.Uni-Halle.de;
Tel: 129 (0) 345 55 25 664; Fax: 149 (0) 345 55 27346
bInstitute of Inorganic Chemistry, Martin-Luther-University Halle-Wittenberg, Kurt-Mothes-
Str. 2, 06120 Halle, Germany
cUniversity of Birmingham, School of Chemistry, Edgbaston, Birmingham, England,
UK B15 2TT
dInstitute of Pharmaceutical Technology und Biopharmacy, Martin-Luther-University Halle-
Wittenberg, Wolfgang-Langenbeck-Straße 4, 06120 Halle, Germany
Received 21st October 2002, Accepted 21st January 2003
First published as an Advance Article on the web 27th February 2003
Several different macrocyclic liquid crystals consisting of two calamitic 2-phenylpyrimidine or
5-phenylpyrimidine units connected at both ends by polyether or alkyl chains have been synthesised by
macrocyclisation reactions under high dilution conditions. The nature of the rigid core has a strong impact on
the liquid crystalline phases formed. All 2-phenylpyrimidine paracyclophanes show nematic phases, whereas for
the series of the 5-phenylpyrimidine derivatives smectic A-phases are exclusively formed. This behaviour is
related to conventional calamitic phenylpyrimidine liquid crystals, but the mesophases are strongly stabilised in
the macrocycles. An exchange of polyether chains by alkyl chains leads to significant mesophase stabilisation,
whereas increasing the spacer length reduces mesophase stability. Pre-organization of the calamitic cores and
micro-segregation of chemically distinct molecular parts are discussed as reasons for the observed effects of
molecular structure on the mesophase behaviour of these compounds.
crystals incorporating phenylpyrimidine rigid cores. Several
Introduction
structurally different paracyclophanes were synthesised, con-
taining either 2-phenyl- or 5-phenylpyrimidine cores, connected
either by polyether chains and/or by aliphatic chains as flexible
linkages between the two rigid heteroaromatic cores (see Tables
1–3 and Fig. 1 and 2).
Since the discovery of the liquid crystalline state the investiga-
tion of the relationship between structure and mesogenic
behaviour is an important area of interest. Most of the known
low molecular mass compounds that form thermotropic liquid
crystalline phases are anisometric molecules with a rigid core
that is rod-like, banana-like or disk-like in shape.1–3 More com-
plex molecular structures and mesophase morphologies4 may
result if two, three or more anisometric units are connected,
leading to mesogenic dimers,5 oligomers6 and polymers.7
Another type of non-conventional liquid crystal is derived
from mesogenic dimers and oligomers by connecting the termi-
nal ends with the formation of rings. These macrocyclic liquid
crystals incorporating conformationally flexible8 or rigid rod-
like9 or bent-core10 groups connected by appropriate flexible
spacer units11 usually exhibit more stable mesophases than the
corresponding low and high molecular weight open chain
liquid crystals. In most of these macrocycles the calamitic cores
are connected end-to-end, but also mesogenic [2.2]paracyclo-
phanes in which rod-like cores are connected side-by-side have
recently been reported.12
Results and discussion
Synthesis
The synthesis of the compounds is shown in Schemes 1–3 (see
Experimental section). The 2-phenylpyrimidine paracyclophanes
Table 1 Phase transition temperatures (T/uC) of 2-phenylpyrimidine
derived paracyclophanesa
In the present work we report on the synthesis and liquid
crystalline properties of a new series of macrocyclic liquid
Compd.
n
m
T/uC
{Electronic supplementary information (ESI) available: the procedures
and analytical data for all compounds and a table with selected bond
distances and bond angles of the crystal structure of compound C are
available as supplementary data. See http://www.rsc.org/suppdata/jm/
b2/b210271d/
A1
A2
A3
A4
A5
A6
A7
1
2
3
1
2
1
3
1
2
3
2
1
3
1
K 178 (N 134) Iso
K 173 (N 136) Iso
K 125 (N 111) Iso
K 184 (N 139) Iso
K 164 (N 126) Iso22
K 154 (N 123) Iso22
K 149 (N 112) Iso22
{Present address: ASV Innovative Chemie GmbH, PF 1128, D-06733
Bitterfeld, Germany.
aAbbreviations: K ~ crystalline solid, N ~ nematic phase, Iso ~
isotropic liquid. Values in parentheses represent monotropic phase
transitions.
§Present address: Queen’s University, Department of Chemistry,
Kingston ON, Canada, K7L 3N6.
}Present address: Probiodrug AG, Weinbergweg 22, D-06120 Halle,
Germany.
778
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This journal is # The Royal Society of Chemistry 2003
DOI: 10.1039/b210271d

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Scheme 3 Synthesis of macrocycle C with antiparallel orientation of
the 5-phenylpyrimidine rigid cores.
Scheme 1 Synthesis of the 2-phenylpyrimidine paracyclophanes
A1–A7.
with two oligo(oxyethylene) spacers A1–A7 were obtained by
the template-mediated Williamson-type etherification of var-
ious oligo(ethylene glycol) ditosylates with the oligo(oxyethy-
lene) bridged 2-phenylpyrimidin-5-ols 2–4 under high dilution
conditions (Scheme 1). Compounds 2–4 were synthesised from
4-(5-benzyloxypyrimidin-2-yl)phenol 1 by etherification with
oligo(ethylene glycol) ditosylates followed by hydrogenolytic
debenzylation. The related 5-phenylpyrimidine derived para-
cyclophanes B1–B3 were prepared in an analogous manner
starting from 5-(4-benzyloxyphenyl)-2-chloropyrimidine 6,
which was obtained by a Suzuki cross-coupling reaction of
5-bromo-2-chloropyrimidine 5 with 4-benzyloxybenzeneboro-
nic acid13 (Scheme 2). Macrocycles with alkyl spacers D–G
were prepared by using 1,v-dibromoalkanes instead of
oligo(ethylene glycol) ditosylates under the same conditions
and with similar yields. A different strategy was used for the
synthesis of the paracyclophane C with an antiparallel
orientation of the rigid cores. Here, the macrocycle C is
formed by the template-mediated etherification of two identical
difunctionalised subunits 10 (Scheme 3).
In general, the yields of the cyclisation steps were
unexpectedly high. The yields of crude product (ca. 95%
purity) were between 50 and 85%, which is much higher than
usually obtained by related macrocyclisation reactions with
4,4’-substituted biphenyl derivatives (20–30% crude product).9b
Probably the N-atoms of the pyrimidine rings are involved in
the pre-organisation of the educts by coordination to the
potassium ions serving as the template. The synthetic
procedures are given in the Experimental section and in the
supplementary information.{
Liquid crystalline properties
The obtained compounds were investigated by polarizing
microscopy to determine the mesomorphic properties. All
synthesised phenylpyrimidine macrocycles form either mono-
tropic (metastable) or enantiotropic (thermodynamically
,The isolated yields of the pure products (see Experimental section)
were much lower due to a significant loss of material during the difficult
purification steps.
Scheme 2 Synthesis of the 5-phenylpyrimidine paracyclophane deriva-
tives B1–B3.
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Table 2 Phase transition temperatures (T/uC) of 5-phenylpyrimidine
derived paracyclophanesa
Compd.
n
m
T/uC
B1
B2
B3
1
2
1
2
2
3
K 147 SmA 163 Iso
K 131 SmA 175 Iso
K 118 SmA 134 Iso
aAbbreviations: SmA ~ smectic A-phase; for the other abbrevia-
tions, see Table 1.
Table 3 Phase transition temperatures (T/uC) of 5-phenylpyrimidine
paracyclophanes G with one polymethylene chain
Compd.
n
m
T/uC
G1
G2
G3
11
8
14
2
3
3
K 128 SmA 203 Iso
K 115 SmA 164 Iso
K 85 SmA 161 Iso
stable) nematic or smectic A liquid crystalline phases, which
were unambiguously confirmed by their very typical textures.
The transition temperatures are summarised in Tables 1–3. In
Fig. 1 and 2, structurally related molecules are compared with
each other and with related non-cyclic phenylpyrimidine liquid
crystals.
The type of liquid crystalline phase formed is determined by
the structure of the calamitic cores, i.e., by the position of the
phenyl ring on the pyrimidine unit. The 2-phenylpyrimidines
(compounds A1–A7 and D–F) form exclusively nematic phases
(Table 1), which are in most cases monotropic, whereas for the
5-phenylpyrimidine series (compounds B1–B3, C and G1–G3)
enantiotropic smectic A-phases are found. Conventional
calamitic liquid crystals incorporating 2-phenyl- or 5-phenyl-
pyrimidine rigid cores14 show very similar mesophase beha-
viour (see Fig. 1). In all cases the 5-phenylpyrimidines have
higher mesophase stabilities and SmA phases are formed,
whereas the 2-phenylpyrimidines show lower clearing tem-
peratures and nematic phases. Thus the position of the nitrogen
atoms in the rigid core has an important influence on the liquid
crystalline phases which may be due to (i) the different
conformations around the linkage between the two aromatic
rings (twisted for 5-phenylpyrimidine derivatives and non-
twisted for compounds with 2-phenylpyrimidine cores), (ii)
differences in the polarizability of the p-systems and (iii)
differences in the total dipole moment.
Fig. 1 Comparison of the mesophase behaviour of the 2-phenyl- and
5-phenylpyrimidine paracyclophanes A2, B2 and C with structurally
related conventional calamitic liquid crystalline phenylpyrimidine
derivatives14 and with related polyether cyclophanes incorporating
biphenyl units instead of one15 or both 2-phenylpyrimidine units.9
cyclophanes of the same size, in which one15 or both
2-phenylpyrimidine cores were replaced by biphenyl units.9
Replacement of one 2-phenylpyrimidine unit has only a
marginal effect, leading to a slight stabilisation of the nematic
phase.
A dramatic change is observed if the second
2-phenylpyrimidine core is also replaced by a biphenyl core.
This gives rise to a strong stabilisation of the liquid crystalline
phase and replacement of the nematic phase by smectic phases
(SmA and crystalline E mesophase). Though these structural
variations have distinct effects on several molecular parameters
including the molecular conformation, all the above mentioned
observations point to a significant influence of micro-segrega-
tion16 on the mesophase stability and on the type of liquid
crystalline phase of these macrocyclic liquid crystals. If polar
molecular segments (polyether chains) and nonpolar segments
(phenyl rings) are well separated within the molecules
Comparison of the mesophase behaviour of compounds B2
and C with either parallel (compound B2) or antiparallel
(compound C) orientation of the dipole moments of their rigid
cores reveals that the direction of the dipole moments within
the molecule has no significant influence on the stability of
the mesophases. Both macrocycles B2 and C form smectic
A-phases with very similar clearing temperatures.
Fig. 1 also compares compound A2 with related polyether
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Fig. 2 Influence of the nature of the bridging units on the liquid
crystalline properties of the 2-phenylpyrimidine series.
(biphenylophanes), they are amphiphilic (more precisely
bolaamphiphilic17 as the lipophilic molecular parts in the
centre are connected to polar groups at each of their opposite
ends). The incompatible parts can segregate into distinct
regions, leading to smectic phases composed of polar sublayers
of the polyether chains and lipophilic sublayers comprising the
aromatic cores. If 2-phenylpyrimidine units replace one or both
biphenyl units, the additional N-atoms in the centre of the
aromatic core introduce polarity also into the aromatic
molecular part. This leads to a reduction of amphiphilicity
and the segregation is significantly decreased. The layer
structure is lost and mesophase formation results predomi-
nately from the parallel alignment of the rigid cores, i.e.
nematic phases are formed. In the case of the 5-phenylpyr-
imidine derivatives the N-atoms are positioned at the periphery
of the lipophilic cores, adjacent to the polar chains, and hence
amphiphilicity is less strongly disturbed if such cores replace
the biphenyl units. This contributes to SmA phase formation
and mesophase stability of the 5-phenylpyrimidine derived
cyclophanes.
Furthermore, it was of interest to study the influence of the
structure of the flexible bridging units. As is obvious from
Fig. 2, replacement of either one (compounds D and E) or both
(compound F) polyether chains by hydrocarbon chains of a
comparable length (13 atoms each) results in stabilisation of
the nematic phase relative to the polyether paracyclophane A2.
Compound D has a rather low melting point and therefore an
enantiotropic nematic phase was obtained in this case.
However, the strongest effect regarding this mesophase
stabilization was observed for F with hydrocarbon spacers
connecting the phenylpyrimidine cores at both ends. Similar
trends were also observed for the series of 5-phenylpyrimidine
Fig. 3 (a) Molecular structure of compound C; (b) molecular packing
of C along the a-axis; (c) molecular packing of C along the b-axis.
paracyclophanes G (Table 3), in this case with stabilization of
the smectic A-phase (compare the pairs B2/G1 and B3/G3 in
Tables 2 and 3). These observations are contrary to the
behaviour observed for previously reported biphenylophane
derivatives, where the replacement of polyether linkages by
aliphatic chains causes a decrease in mesophase stability.9 Also
this observation can be explained by the effect of this structural
variation on the amphiphilicity of the molecules. The alkyl
chains are lipophilic and decrease the incompatibility between
J. Mater. Chem., 2003, 13, 778–784
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calamitic cores and bridging units in the case of the biphenyl-
ophane derivatives, leading to mesophase destabilization. In
the case of the phenylpyrimidine derived polyethercyclophanes,
however, the aromatic cores are polar and replacement of the
polar polyether chains by lipophilic alkyl chains can lead in this
case to an increase of amphiphilicity, contributing to enhanced
mesophase stability.
(with gypsum, Merck) was used for centrifugal force mediated
preparative thin layer chromatography in conjunction with a
Chromatotron from Harrison Research Europe (Muttenz).
Confirmation of the structures of the products and inter-
mediates was obtained by 1H- and 13C-NMR spectroscopy
(Varian Unity 500, Varian Unity 400 or Bruker WP 200
spectrometers) with tetramethylsilane as internal standard,
mass spectroscopy [AMD 402 (electron impact, 70 eV),
Finnigan MAT LCQ spectrometer (CHCl3–MeOH–H2O, c #
10 mg ml21)], and elemental analysis (CHNS elemental
analyser, Leco & Co).28 The purity of all compounds was
checked by thin layer chromatography (Merck, silica gel 60 F
254). The detection was performed by using UV irradiation
(254 and 354 nm) or by means of iodine and/or Dragendorff’s
reagent.29 Transition temperatures were determined using a
Mettler FP HAT hot stage and control unit in conjunction with
a Nikon Optiphot 2 polarizing microscope. Experimental
procedures and analytical data (3’,5’ and 2’,6’ are positions at
the phenyl ring and 4,6 at the pyrimidine ring) are given for
compounds A2, B2, C, D, E and G3 as representative examples.
The procedures and analytical data of all other compounds,
including the intermediates, are available as supplementary
information.{
Crystal structure of compound C
In the case of compound C we were able to grow single crystals
suitable for single crystal X-ray structure analysis. The crystal
structure of C (Fig. 3) shows that the macrocycle is self-filling.
This means that the two 5-phenylpyrimidine units are aligned
parallel and staggered with respect to each other about a
crystallographic centre of symmetry, and the aromatic rings
within each 5-phenylpyrimidine unit are twisted with respect to
each other. This geometry is commensurate with conventional
p-stacking systems.18 The molecules pack to form chevron-like
sheets (Fig. 3c) that have adjacent layers oriented to optimise
T-type edge-to-face interactions19 between the aromatic
components. For a list of bond length and bond angles, see
supplementary information.{
Single crystals of C were crystallised from CHCl3–CH3CN,
mounted in inert oil and transferred to the cold air stream of
the diffractometer.
Conclusions
In summary, novel liquid crystalline polyether cyclophanes
have been synthesised and investigated. As reported also in
previous work,8,9 the macrocyclic approach has a strong
mesophase stabilising effect. The type of rigid core incorpo-
rated into such macrocylic liquid crystals, either 2-phenylpyri-
midine or 5-phenylpyrimidine units, has a strong impact on the
liquid crystalline phase formed. All 2-phenylpyrimidine para-
cyclophanes show exclusively nematic phases, whereas within
the series of the 5-phenylpyrimidine derivatives smectic
A-phases are exclusively present. It was also shown that the
nature of the flexible linking units, either polyether chains or
alkyl chains, influences the mesophase stability, in some cases
quite drastically. Here, in contradiction to earlier work,9a
exchange of polyether spacers by alkyl chains leads to meso-
phase stabilisation. The influence of these structural changes on
the amphiphilicity of the molecules, leading to different degrees
of microsegregation, should significantly contribute to the
observed effects.
Crystal structure determination of compound C
Crystal data. C36H44N4O10, M ~ 692.77, orthorhombic,
˚
a ~ 8.976(2), b ~ 16.220(3), c ~ 23.691(7) A, V ~ 3449.0(14)
3
˚
˚
A , T ~ 293(2) K, space group: Pcab, Z ~ 4, l ~ 0.71073 A,
m ~ 0.098 mm21, F(000) ~ 1472, H ~ 2.13–24.00u. Measured
reflections: 11807, 2616 unique (Rint ~ 0.1987); refinement
method: full-matrix least-squares on F2, goodness-of-fit on
2
23
˚
F ~ 0.830, maximum residual-electron density ~ 0.226 eA
.
R values: [I w 2s(I)]; R1 ~ 0.0547, wR2 ~ 0.0914; (all data):
R1 ~ 0.1691, wR2 ~ 0.1237).
CCDC reference number 195726.
See http://www.rsc.org/suppdata/jm/b2/b210271d/ for crys-
tallographic files in .CIF or other electronic format.
Synthesis of the paracyclophanes A2, B2, C, D, E and G3
6,9,12,15,18,27,30,33,36,39-Decaoxa-3,21,47,50-tetraazapenta-
cyclo[38.2.2.22,5.219,22.223,26]pentaconta-1(42),2,4,19,21,23,25,40,
43,45,47,49-dodecaene (A2). A solution of 1,11-bis[4-(5-hydro-
xypyrimidin-2-yl)phenoxy]-3,6,9-trioxaundecane 3 (0.30 mmol,
0.153 g) and 1,11-bis(toluene-4-sulfonyloxy)-3,6,9-trioxaunde-
cane (0.30 mmol, 151 mg) in dry DMF (100 ml) was added at
80 uC to a suspension of potassium carbonate (3 mmol, 414 mg)
and potassium toluene-p-sulfonate (3 mmol, 630 mg) in dry
DMF (20 ml) over a period of 24 hours (micro dispense pump,
Dosca, HPLH 200MS) under an Ar atmosphere. The result-
ing solution was stirred at this temperature for an additional
172 hours. After cooling to room temperature the solvent was
removed under reduced pressure and the residue was parti-
tioned between CH2Cl2 and water (150 ml : 75 ml). The layers
were separated and the organic layer was washed successively
with 20 ml portions of 5 M HCl, saturated sodium bicarbonate
solution, distilled water and brine, and was dried over Na2SO4.
Evaporation of the solvent resulted in a crude product, which
was purified by chromatography(Chromatotron,CH2Cl2–EtOH
~ 10 : 0.5...2) and repeated crystallisation from EtOH–toluene
and heptane to yield 65 mg (32%) A2. Transition temperatures/
uC: K 173 (N 136) Iso; HRMS m/z: C36H44N4O10 requires
693.3135 [M 1 1]1; found 693.3156; 1H-NMR (CDCl3,
500 MHz) dH 3.66–3.69 (m, 4H, OCH2), 3.70–3.73 (m, 4H,
By increasing the spacer length in all series, the stability of
the liquid crystalline phases decreases, i.e. decoupling the
calamitic units reduces the pre-organisation of the rigid cores
and leads to mesophase destabilisation for entropic reasons.
The most remarkable feature of these novel materials is that
they incorporate donor atoms, which enable ortho-metallation
reactions20,21 (2-phenylpyrimidines) leading to several novel
and quite interesting classes of metallo-bridged macrocycles
(metallomesogens) capable of forming smectic and columnar
mesophases.15,22 Moreover these materials may be of more
general interest as building blocks for other supramolecular
systems.
Experimental section
General methods
Benzyloxybenzeneboronic acid,23 oligo(ethylene glycol) dito-
sylates,24 and 5-bromo-2-chloropyrimidine 513 were synthesised
according to literature procedures. Tetrakis[triphenylphosphane]-
palladium(0)25 was used as received. The oligo(ethylene glycols)
used were distilled in vacuo and stored over molecular sieves.
Solvents were purified and dried according to standard pro-
cedures26 and checked for water content by using the Karl-
Fischer method.27 Silica gel 60 (0.040–0.036 mm, Merck) was
used for flash column chromatography and Silica gel 60 PF254
3
3
OCH2), 3.83 (t, J 4.8 Hz, 4H, OCH2CH2), 3.86 (t, J 4.6 Hz,
4H, OCH2CH2), 4.02 (t, 3J 4.8 Hz, 4H, OCH2), 4.16 (t, 3J
782
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3
3
3
3.82 (t, J 4.7 Hz, 4H, OCH2CH2), 4.03 (t, overlapped, J 6.7
3
4.6 Hz, 4H, OCH2), 6.83 (d, J 8.8 Hz, 4H, H3’,5’), 8.13 (d, J
8.8 Hz, 4H, H2’,6’), 8.36 (s, 4H, H4,6); 13C-NMR (100 MHz,
CDCl3): dC 67.50, 68.45, 69.52, 69.68, 70.78, 70.86, 70.92, 70.96
(OCH2), 114.49 (C-3’,5’), 129.12 (C-2’,6’), 130.27 (C-1’), 144.11
(C-4,6), 151.00 (C-2), 157.98 (C-4’), 160.46 (C-5); EIMS m/z
(relative intensity, %): 692 [M]1 (51), 662 (6), 649 (42), 605 (21),
561 (50), 547 (10), 534 (23), 347 (18), 334 (20), 290 (16), 281
(12), 267 (15), 259 (23), 241 (24), 227 (21), 215 (100), 188 (35),
121 (62), 108 (32); ESI-MS m/z (relative intensity, %): 731 [M 1
K]1 (36), 715 [M 1 Na]1 (81), 693 [M 1 H]1 (100).
3
Hz, 4H, OCH2), 4.07 (t, overlapped, J 4.7 Hz, 4H, OCH2),
6.88 (d, 3J 8.8 Hz, 4H, H3’,5’), 8.22 (d, 3J 8.8 Hz, 4H, H2’,6’), 8.35
(s, 4H, H4,6).
6,9,12,15,18,27,39-Heptaoxa-3,21,47,50-tetraazapentacyclo-
[38.2.2.22,5.219,22.223,26]pentaconta-1(42),2,4,19,21,23,25,40,43,
45,47,49-dodecaene (E). CompoundEwassynthesisedfrom1,11-
bis[4-(5-hydroxypyrimidin-2-yl)phenoxy]undecane 11 (0.3 mmol,
148 mg), 1,11-bis(toluene-4-sulfonyloxy)-3,6,9-trioxaundecane
(0.3 mmol, 150 mg), K2CO3 (3 mmol, 414 mg) and KOTs
(3 mmol, 630 mg) in dry DMF (140 mL) and purified by
chromatography (Chromatotron, CH2Cl2–EtOH ~ 10: 0.5...2)
and repeated crystallisation from heptane to yield 45 mg (22%)
E. Transition temperatures/uC: K 146 (N 145) Iso; HRMS m/z:
C39H50N4O7 requires 687.3757 [M 1 1]1; found 687.3773;
1H-NMR (CDCl3, 500 MHz): dH 1.24–1.34 (m, 10H, CH2),
6,9,12,15,18,27,30,33,36,39-Decaoxa-4,20,48,49-tetraazapenta-
cyclo[38.2.2.22,5.219,22.223,26]pentaconta-1(42),2,4,19,21,23,25,
40,43,45,47,49-dodecaene (B2). Compound B2 was synthesised
from 1,11-bis[5-(4-hydroxyphenyl)pyrimidin-2-yloxy]-3,6,9-trioxa-
undecane 7 (0.082 mmol, 42 mg), 1,11-bis(toluene-4-sulfonyl-
oxy)-3,6,9-trioxaundecane (0.082 mmol, 41 mg), K2CO3 (1 mmol,
138 mg) and KOTs (1 mmol, 210 mg) in dry DMF (70 mL) and
purified by chromatography (Chromatotron, CH2Cl2–EtOH ~
10 : 0.5...2) and repeated crystallisation from toluene–heptane
to yield 9 mg (16%) B2. Transition temperatures/uC: K 131 SmA
175 Iso; HRMS m/z: C36H44N4O10 requires 693.3135 [M 1 1]1;
3
1.40–1.44 (m, 4H, CH2), 1.73 (t, J 6.7 Hz, 4H, OCH2CH2),
3.64–3.66 (m, 4H, OCH2), 3.68–3.71 (m, 4H, OCH2), 3.83 (t, 3J
4.6 Hz, 4H, OCH2CH2), 3.95 (t, 3J 6.7 Hz, 4H, OCH2), 4.17 (t,
3
3J 4.6 Hz, 4H, OCH2), 6.88 (d, J 8.8 Hz, 4H, H3’,5’), 8.21 (d,
3J 8.8 Hz, 4H, H2’,6’), 8.39 (s, 4H, H4,6); 13C-NMR (100 MHz,
CDCl3): dC 25.16, 27.72, 27.99, 28.12, 28.58 (CH2), 67.77,
68.44, 69.54, 70.77, 70.95 (OCH2), 114.51 (C-3’,5’), 129.13
(C-2’,6’), 130.00 (C-1’), 144.26 (C-4,6), 151.01 (C-2), 158.10
(C-4’), 160.87 (C-5); EIMS m/z (relative intensity, %): 686 [M]1
(100), 657 (6), 643 (11), 615 (4), 559 (19), 547 (7), 215 (12), 188
(26), 171 (11); ESI-MS m/z (relative intensity, %): 715 [M 1
K]1 (28), 709 [M 1 Na]1 (29), 693 [M 1 Li]1 (34), 687 [M 1
H]1 (100), 669 (9).
1
found 693.3163; H-NMR (CDCl3, 500 MHz) dH 3.65–3.67 (m,
4H, OCH2), 3.68–3.75 (m, 12H, OCH2), 3.87 (t, J 4.7 Hz, 4H,
3
OCH2CH2), 3.91 (t, 3J 4.9 Hz, 4H, OCH2CH2), 4.04 (t, 3J 4.7 Hz,
4H, OCH2), 4.51 (t, 3J 4.9 Hz, 4H, OCH2), 6.89 (d, 3J 8.6 Hz, 4H,
H3’,5’), 7.22 (d, 3J 8.6 Hz, 4H, H2’,6’), 8.50 (s, 4H, H4,6); 13C-NMR
(100 MHz, CDCl3): dC 67.06, 67.69, 69.24, 69.64, 70.76, 70.85,
70.89, 70.92 (OCH2), 115.42 (C-3’,5’), 127.00 (C-1’), 127.52
(C-2’,6’), 127.78 (C-5), 156.79 (C-4,6), 159.12 (C-4’), 164.37
(C-2); EIMS m/z (relative intensity, %): 692 [M]1 (50), 649 (38),
561 (47), 215 (100), 188 (34), 121 (63).
6,9,12,15,18,21,30,45-Octaoxa-4,23,54,55-tetraazapentacyclo-
[44.2.2.22,5.222,25.226,29]hexapentaconta-1(48),2,4,22,24,26,28,46,
49,51,53,55-dodecaene (G3). Compound G3 was synthesised
from 1,14-bis[5-(4’-hydroxyphenyl)pyrimidin-2-yloxy]-3,6,9,12-
tetraoxatetradecane 8 (0.24 mmol, 141 mg), 1,14-dibromotetra-
decane (0.24 mmol, 86 mg), K2CO3 (3 mmol, 414 mg) and KOTs
(3 mmol, 630 mg) in dry DMF (120 mL) and purified by
chromatography (Chromatotron, CH2Cl2–EtOH ~ 10: 0.5...2)
and repeated crystallisation from heptane to yield 12 mg (6%) G3.
Transition temperatures/uC: K 85 SmA 161 Iso; anal. for
C44H60N4O8?0.5H2O requires: C 67.58, H 7.86, N 7.16; found C
67.88, H 7.81, N 7.02%; 1H-NMR (CDCl3, 400 MHz): dH 1.38–
1.40 (m, 12H, CH2), 1.46–1.50 (m, 4H, CH2), 1.74–1.81 (m, 4H,
CH2), 3.63 (s, 4H, OCH2), 3.63–3.71 (m, 8H, OCH2), 3.91 (t,
3J 5.0 Hz, 4H, OCH2CH2), 3.97 (t, 3J 6.5 Hz, 4H, OCH2), 4.60 (t,
3J 5.0 Hz, 4H, OCH2), 6.96 (d, 3J 7.8 Hz, 4H, H3’,5’), 7.39 (d, 3J
7.8 Hz, 4H, H2’,6’), 8.67 (s, 4H, H4,6).
6,9,12,15,18,27,30,33,36,39-Decaoxa-4,25,45,49-tetraazapenta-
cyclo[38.2.2.22,5.219,22.223,26]pentaconta-1(42),2,4,19,21,23,25,
40,43,45,47,49-dodecaene (C). Compound C was synthesised
from 4-{2-[11-(toluene-4-sulfonyloxy)-3,6,9-trioxaundecan-1-
yloxy]pyrimidin-5-yl}phenol 10 (0.60 mmol, 0.35 g), K2CO3
(3 mmol, 0.41 g) and KOTs (3 mmol, 0.63 g) in dry DMF
(100 mL) and purified by chromatography (Chromatotron,
CH2Cl2–EtOH ~ 10 : 0.5...2) and repeated crystallisation from
CH2Cl2–MeOH and CH2Cl2–EtOH to yield 10.6 mg (5%) C.
Transition temperatures/uC: K 140 SmA 169 Iso; HRMS
m/z: C36H44N4O10 requires 693.3135 [M
693.3105; 1H-NMR (CDCl3, 500 MHz): dH 3.68–3.71 (m,
8H, OCH2), 3.89–3.91 (m, 8H, OCH2), 4.10 (t, J 4.5 Hz, 4H,
1
1]1; found
3
OCH2CH2), 4.47 (m, 4H, OCH2), 6.88 (d, 3J 8.4 Hz, 4H, H3’,5’),
7.24 (covered, 4H, H2’,6’), 8.49 (s, 4H, H4,6); 13C-NMR
(100 MHz, CDCl3): dC 67.14, 67.86, 69.42, 69.68, 70.82,
70.89, 71.08 (OCH2), 115.62 (C-3’,5’), 126.63 (C-1’), 127.53
(C-2’,6’), 128.04 (C-5), 156.88 (C-4,6), 159.28 (C-4’), 164.23
(C-2); EIMS m/z (relative intensity, %): 692 [M]1 (100); ESI-
MS m/z (relative intensity, %): 731 [M 1 K]1 (24), 715 [M 1
Na]1 (36), 693 [M 1 H]1 (100).
Acknowledgements
This work was supported by the Deutsche Forschungsge-
meinschaft (DFG) and the Fonds der Chemischen Industrie.
References
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