Synthesis of a new class of difunctional tetraphenylene crown ethers

Article abstract of DOI:10.1139/v98-188

Three new substituted tetraphenylene crown ethers have been made. Bis(5- carbomethoxy-1,3-phenylene)-bis(p-phenylene)-(3x + 6)-crown-x, where x = 12, 16, and 20 (11b-11d) were synthesized via [1 + 1] cyclization of methyl 3,5- bis[ω-chloro(oligoethyleneoxy)]benzoates (13b-3d) with methyl 3,5-bis[ω- (p-hydroxyphenoxy)(oligoethyleneoxy)]benzoates (16b-6d) using K₂CO₃ as base and tetrabutylammonium iodide as a phase transfer agent in dimethylformamide (DMF). The corresponding 30-membered (x = 8) macrocycle 11a could not be made by this approach; only the elimination product, 3,5-bis(vinyloxy)benzoic acid (19), was isolated. 16a-16d were made via alkylation of p-benzyloxyphenol (14) with 13a-13d, respectively, followed by hydrogenolysis with Pd/C as catalyst. No complexation of these macrocycles with dibenzylammonium ions was detected by NMR spectroscopy, but weak complexation of 11d with a paraquat derivative was observed.

Full text of DOI:10.1139/v98-188

1429
Synthesis of a new class of difunctional
tetraphenylene crown ethers
Harry W. Gibson, Devdatt S. Nagvekar, Yadollah Delaviz, and William S. Bryant
Abstract: Three new substituted tetraphenylene crown ethers have been made. Bis(5-carbomethoxy-1,3-phenylene)-
bis(p-phenylene)-(3x + 6)-crown-x, where x = 12, 16, and 20 (11b–11d) were synthesized via [1 + 1] cyclization of
methyl 3,5-bis[ω-chloro(oligoethyleneoxy)]benzoates (13b–3d) with methyl 3,5-bis[ω-(p-hydroxyphenoxy)(oligo-
ethyleneoxy)]benzoates (16b–6d) using K2CO3 as base and tetrabutylammonium iodide as a phase transfer agent in
dimethylformamide (DMF). The corresponding 30-membered (x = 8) macrocycle 11a could not be made by this
approach; only the elimination product, 3,5-bis(vinyloxy)benzoic acid (19), was isolated. 16a–16d were made via
alkylation of p-benzyloxyphenol (14) with 13a–13d, respectively, followed by hydrogenolysis with Pd͞C as catalyst.
No complexation of these macrocycles with dibenzylammonium ions was detected by NMR spectroscopy, but weak
complexation of 11d with a paraquat derivative was observed.
Key words: crown ethers, cyclization, macrocycles.
Résumé : On a préparé trois nouveaux éthers couronnes de type tétraphénylène substitué. On a synthétisé les bis(5-
carbométhoxy-1,3-phénylène)-bis(p-phénylène)-(3x + 6)-couronnes-x, dans lesquelles x = 12, 16 et 20 (11b–11d) par le
biais d’une cyclisation [1 + 1] des 3,5-bis[ω-chloro(oligoéthylèneoxy)]benzoates de méthyle (13b–13d) avec les 3,5-bis[ω-
(p-hydroxyphénoxy)(oligoéthylèneoxy)]benzoates de méthyle (16b–16d) dans le diméthylformamide (DMF), en
présence de K2CO3 agissant comme base et d’iodure de tétrabutylammonium agissant comme agent de transfert de
phase. Utilisant cette méthode, il n’a pas été possible de préparer le macrocycle correspondant à trente chaînons (x =
8) (11a); on n’a isolé que le produit d’élimination, l’acide 3,5-bis(vinyloxy)benzoïque (19). On a préparé les produits
16a–16d par le biais d’alkylations du p-benzylphénol (14) avec les esters 13a–13d, suivies d’une hydrogénolyse avec
du Pd͞C comme catalyseur. Par spectroscopie RMN, on n’a pas pu détecter de complexation de ces macrocycles avec
les ions dibenzylammonium; on a toutefois observé une faible complexation du composé 11d avec un dérivé du
paraquat.
Mots clés : éthers couronnes, cyclisation, macrocycles.
[Traduit par la Rédaction] Gibson et al. 1436
Larger macrocycles are also of interest for these and re-
lated applications. Bis(p-phenylene)-bis(m-phenylene)-66-
Crown ethers are an interesting class of molecules which
crown-20 (1b) was isolated in 11% yield (6) as a [2 + 2] by-
are known for their ability to complex with a wide variety of
product from the [1 + 1] synthesis of p-phenylene-m-phenyl-
cations, including metal and organic species (1). We are in-
ene-33-crown-10 (1a) (7). Cyclization of resorcinol with
terested in macrocyclic polyethers which are semi-flexible in
tetra(ethylene glycol) ditosylate generated [1 + 1], [2 + 2],
nature and have the ability to undergo complexation with
and [3 + 3] products, m-phenylene-16-crown-5 (2a), bis-m-
linear molecules to form pseudorotaxanes, rotaxanes, and
phenylene-32-crown-10 (2b), and tris(m-phenylene)-48-
polyrotaxanes (see reviews in ref. 2a–f) of various types. A
crown-15 (2c) in 54, 8.4, and 1.7% yields, respectively (8).
Tris(p-phenylene)-51-crown-15 (3b) and tetrakis(p-phenyl-
ene)-68-crown-20 (3c) have been reported (9) and shown to
number of bisphenylene crown ethers with ring sizes from
24–34 atoms have been synthesized previously in our la-
boratory (3–5) for these purposes (2a, b, g–o; for poly(urethane
act as templates for paraquat units (5) in catenane syntheses
crown ether rotaxane)s see ref. 2g; for poly(ester crown
and as hosts for dibenzylammonium ion (6), forming pseu-
ether rotaxane)s see refs. 2h and i; for poly(methacrylate
dorotaxanes with varying stoichiometries (10a). And recently
crown ether side chain rotaxane)s see ref. 2j; for self-
the corresponding analogous 1,5-dioxynaphthalene family of
assembled supramolecular structures see refs. 2k–o).
crown ethers was expanded to include the bis-, tris-, and
tetrakis- species 4a–4c; these hosts were used in catenane
syntheses using cyclobis(paraquat-arylene)s (10b). These re-
ports have prompted us to describe our efforts with bis(5-
carbomethoxy-1,3-phenylene)-bis(p-phenylene)-(3x + 6)-crown-x
(11a–11d) systems, which began in 1990.
Received March 4, 1998.
H.W. Gibson,1 D.S. Nagvekar, Y. Delaviz, and W.S.
Bryant. Department of Chemistry, Virginia Polytechnic
Institute and State University, Blacksburg, VA 24061, U.S.A.
1Author to whom correspondence may be addressed.
Telephone: (540) 231–5902. Fax: (540) 231–8517.
E-mail: hwgibson@vt.edu
Our ongoing efforts led us to focus our attention on tetra-
phenylene macrocycles with ring sizes between 42 and 66
atoms.
Can. J. Chem. 76: 1429–1436 (1998)
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Can. J. Chem. Vol. 76, 1998
2. The [1 + 1] cyclization approaches
The more efficient [1 + 1] cyclization approaches to higher
cyclic oligomers requires the syntheses of larger building
blocks, but allows the more effective use of pseudo-high di-
lution (syringe pump addition) techniques (11, 12). Tetra-
phenylene crown ethers 11 were approached by the method
depicted in Scheme 3.
1. The [2 + 2] cyclization approaches
Although it is well known that multistep methods are
more efficient for large oligomeric macrocycles than direct
[n + n] approaches (11, 12), the latter have the appeal of us-
ing simple starting materials in a one-step procedure reac-
tion sequence. Thus, we initially attempted the synthesis of
tetraphenylene crown ethers in this way.
(a) Dihalide intermediates 13
Methyl 3,5-bis(5-chloro-3-oxapentyloxy)benzoate (13b),
methyl 3,5-bis(8-chloro-3,6-dioxaoctyloxy)benzoate (13c),
and methyl 3,5-bis(11-chloro-3,6,9-trioxaundecyloxy)benzo-
ate (13d) were each synthesized in one step by reacting large
excesses of di-, tri-, and tetra-(ethylene glycol) dichlorides
(12b–12d), respectively, with the disodium salt of methyl
3,5-dihydroxybenzoate (10) (Scheme 3), as previously re-
ported (3, 4).
The generic [2 + 2] route to bis(5-carbomethoxy-1,3-
phenylene)-bis(p-phenylene)-(3x + 6)-crown-x (11) (Schemes
1 and 2) involves preparation of bis[ω -chloro(oligoethylene-
oxy)] derivatives (9) of hydroquinone and their condensa-
tions with methyl 3,5-dihydroxybenzoate (10).
This route to bis(5-carbomethoxy-1,3-phenylene)-bis(p-
phenylene)-30-crown-8 (11a) was explored via synthesis of
diol 8a and its conversion to the corresponding dichloride
9a, both in good yields. However, from the attempted cycli-
zation of 9a with 10 we were unable to isolate the desired
11a.
The larger bis(5-carbomethoxy-1,3-phenylene)-bis(p-
phenylene)-42-crown-12 (11b) was approached in an ana-
ologous manner. Hydroquinone was alkylated with 2-[2′-(2′′-
chloroethoxy)ethoxy]tetrahydropyran (7b), and the resultant
THP ether was deprotected to afford p-bis[2-(2′-hydro-
xyethoxy)ethoxy]benzene (8b). Treatment of 8b with thionyl
chloride produced p-bis[2-(2′-chloroethoxy)ethoxy]benzene
(9b). Attempts to isolate macrocycle 11b from condensation
of bisphenol 10 and 9b were fruitless.
A
one-pot synthesis of methyl 3,5-bis(2-chloro-
ethoxy)benzoate (13a) was also attempted by reacting a sus-
pension of the disodium salt of methyl 3,5-
dihydroxybenzoate (10) with a large excess of dichloro-
ethane (12a) in DMF. Thin layer chromatography (TLC) in-
dicated a considerable amount of starting benzoate 10 along
with the desired product 13a, which was obtained (10%)
upon Soxhlet extraction. Even at longer reaction times con-
siderable amounts of starting material were found.
To synthesize methyl 3,5-bis(2-hydroxyethoxy)benzoate
as a precursor to 13a, the dianion of methyl 3,5-dihydroxy-
benzoate (10), generated in situ with potassium carbonate,
was reacted with chloroethanol (7a) at 70°C for three days.
© 1998 NRC Canada

Gibson et al.
1431
Scheme 1.
Scheme 2.
Less than a 10% yield of pure product was obtained. The
use of THP protected chloroethanol (7c) was then examined.
Treatment of methyl 3,5dihydroxybenzoate (10) with so-
dium hydride in DMF followed by reaction with 7c gave
(77%) after deprotection the desired intermediate methyl
3,5-bis(2-hydroxyethoxy)benzoate. After work-up this com-
pound was without purification converted (88%) to the cor-
responding dichloride 13a with thionyl chloride and pyridine
in benzene.
were purified via flash silica gel chromatography and char-
acterized by NMR and FAB MS.
Removal of the benzyl groups from 15a–15d via hydro-
genolysis with palladium on carbon as catalyst gave the de-
sired bisphenols 16a–16d in 90–99% yields (Scheme 3).
(c) Cyclization reactions to form macrocycles 11
Our previous cyclization studies showed that the yields
were either higher (20- and 26-membered) (5) or almost
identical (32-membered) (3, 4) with potassium salts, as com-
pared to the more expensive cesium salts. Thus, we used po-
tassium carbonate as the base in the [1 + 1] cyclization of
the bisphenols 16b–16d with dichlorides 13b–13d in DMF
at 110°C (Scheme 3). This method provided macrocycles
11b–11d in 17–24% yields.
The cyclization of methyl 3,5-bis[2-(p-hydroxyphen-
oxy)ethoxy]benzoate (16a) with methyl 3,5-bis(2-chloro-
ethoxy)benzoate (13a) under these conditions was not
successful. Therefore, cyclization was attempted at 85°C us-
ing sodium hydride as base in DMF via the syringe pump
technique. Sodium was used as the metal ion to match the
small cavity size of 30-membered 11a. However, we were
able to isolate only (19%) 3,5-bis(vinyloxy)benzoic acid
(19), the product of two elimination reactions.
(b) Bisphenols 16
The synthesis of the second fragment for cyclization to
11a, methyl 3,5-bis[2-(p-hydroxyphenoxy)ethoxy]benzoate
(16a), was initiated via reaction of p-benzyloxyphenol (14)
with methyl 3,5-bis(2-chloroethoxy)benzoate (13a) using so-
dium hydride as base (Scheme 3), but this did not result in
the formation of product 15a. A three-step approach to 15a
was then evaluated (Scheme 4). Reaction of THP protected
chloroethanol (7c) with p-benzyloxyphenol (14) and subse-
quent deprotection gave p-(2-hydroxyethoxy)benzyloxyben-
zene (17) in quantitative yield. The compound 17 was
converted to the chloro derivative 18 with thionyl chloride
and pyridine. Reaction of methyl 3,5-dihydroxybenzoate
(10) with 18 using sodium hydride as base gave (60%) the
desired product, methyl 3,5-bis[2(p-benzyloxyphenoxy)etho-
xy]benzoate (15a).
(d) Attempted complexation with dibenzylammonium salt 6
Bis(o- and p-phenylene) crown ethers are known to com-
plex strongly with secondary ammonium ions, such as
dibenzylammonium hexafluorophosphate (6), yielding pseu-
Methyl 3,5-bis{[p-(benzyloxy)phenoxy]oligoethyleneoxy-
benzoates (15b–15d) were produced via reaction of p-
benzyloxyphenol (14) with dichlorides 13b–13d using so-
dium hydride as the base (Scheme 3). These intermediates
1
dorotaxanes (2c, e, f, 10a, 13) In the present work, in the H
NMR spectra of CDCl3 solutions of 11b–11d (individually)
in the presence of solid ammonium salt 6 there were no indi-
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1432
Can. J. Chem. Vol. 76, 1998
Scheme 3.
for 3b:(6)2 (13, 14). The difference in the association con-
stants, therefore, must be a result of poorer preorganization
in the case of 2b. In 11b–11d the electron-withdrawing
carbomethoxy groups on the m-phenylene units further de-
crease the tendency for the m-phenylene moieties to undergo
complexation. However, the hydroquinol ether linkages
were expected to provide suitable sites. The only explana-
tion for the lack of complexation of secondary ammonium
ions by 11b–11d seems to be that the conformational prop-
erties imbued by the m-phenylene units are such that
complexation is entropically unfavorable.
Scheme 4.
(e) Complexation with paraquat diol 5b
The complexation of paraquat (5a) with bis(m-phenyl-
ene)-32-crown-10 and bis(p-phenylene)-34-crown-10 is
driven primarily by hydrogen bonding of the α-protons of
the bipyridinium units with the ether oxygen atoms, but also
involves donor–acceptor, π-stacking, and dipole–dipole at-
tractions (15). It has been deduced that, because four ethyl-
eneoxy units serve to maximize the association constants,
hydrogen bonding of the central oxygen atom in the
tetra(ethyleneoxy) segment is most important, but that the
next nearest oxygen atom plays a role by an allosteric effect
(16). X-ray crystallographic results show that both of these
interactions are in force in the solid state (6, 9, 15).
Upon mixing solutions of 11d with 5b a pale yellow–or-
ange color indicative of charge transfer was observed; in the
1H NMR spectra shifts of the signals for the hydroquinol
unit proton, the intra-annular aromatic proton of the m-
phenylene unit and the CH2O group adjacent to the hydro-
quinol unit were observed. Although we have not yet deter-
mined the stoichiometry of this complex, it is clear that
some relatively weak complexation takes place. Studies with
crown ethers containing m-phenylene linkages in compari-
son to their p-linked counterparts, e.g., 2b vs. 3b, and inter-
nally in catenanes derived from 1a, have demonstrated the
preference of paraquat (5a) complexation centered on the p-
phenylene units (6). Thus, we hypothesize that the hydro-
quinol units of 11d are the active sites, especially since we
have shown that the electron-withdrawing carbomethoxy
groups in bis(5-carbomethoxy-1,3-phenylene)-32-crown-10
cations of complexation, i.e., no changes of chemical shifts
of the proton signals; furthermore, the ammonium salt did
not dissolve in CDCl3 solutions of the crown ethers, a good
qualitative test for complex formation.
The inclusion complexation of secondary ammonium ions
such as 6 by crown ethers appears to be relatively facile
based on the isolation of pseudorotaxanes of various stoichi-
ometries for benzo and p-phenylene macrocycles ranging
from dibenzo-24-crown-8 to tetrakis(p-phenylene)-68-crown-
20 (3d) (10a, 13). As deduced from single crystal X-ray
structures, the N-H—O bonds in these complexes involve
both the phenolic and ethyleneoxy oxygen atoms, as do the
benzylic C-H—O bonds, in some cases augmented by π–π
interactions. However, we have found that bis(m-phenylene)
crown ethers complex either very weakly or not at all with
secondary ammonium ions (14). Bis(m-phenylene)-26-
crown-8, in spite of its homology with dibenzo-24-crown-8,
which efficiently yields a pseudorotaxane (13), does not give
any indication of complexation with 6 by NMR spectros-
copy. The larger bis(m-phenylene)-32-crown-10 (2b), like its
34-membered p-analog 3b (13), gives [3]pseudorotaxanes
with two ammmonium ions as guests, but its association
constants are quite low (<10 M–1) (14). X-ray analysis of the
crystalline [3]pseudorotaxane 2b:(6)2 revealed that the struc-
ture and attractive forces are very similar to those reported
© 1998 NRC Canada

Gibson et al.
1433
are detrimental for complexation of paraquats.2
Current work is aimed at determining the stoichiometry of
the complex of 11d with 5b, so that its association constant
can be measured, and, hopefully, obtaining crystals suitable
for X-ray analysis.
149.5 g (79%) of crude product, which was recrystallized
from EtOAc: mp 102–103°C, lit. (21) oil. 1H NMR, δ (ppm):
3.79 (t, J = 7 Hz, 4H), 4.19 (t, J = 7 Hz, 4H), 6.87 (s, 4H).
MS (EI), m͞z: 238 [(M 37Cl2)+, 10%], 236 [(M 37Cl 35Cl)+,
67%], 234 [(M 35Cl2)+, 100%], 171 [(M 35Cl2 – CH2CH2Cl),
90%], 109 [(M – 2(CH2CH2Cl)), 100%].
p-Bis[2-(2′-chloroethoxy)ethoxy]benzene (9b)
Application of the above procedure to 8b produced (85%)
crude 9b, which was recrystallized from EtOAc: mp 62.2–
Materials
Unless specified otherwise, reagent grade reactants and
solvents were used as received from chemical suppliers. The
compounds 5b (17), 6 (13), 7b (18), 7c (19), 10 (20), 13b
(3), 13c (3), and 13d (4) were synthesized according to liter-
ature procedures.
1
64.0°C, lit. (21) oil. H NMR, δ (ppm): 3.6–4.2 (m, 16H),
6.85 (s, 4H). MS (EI), m͞z: 324 [(M 37Cl 35Cl)+, 24%], 322
[(M 35Cl2)+, 35%], 113 (100%). Anal. calcd. for
C14H20Cl2O4: C 52.02, H 6.24; found: C 51.88, H 6.25.
Methyl 3,5-bis(2-hydroxyethoxy)benzoate
Instrumentation and techniques
NaH (5.14 g, 128 mmol, 60% in mineral oil) was added to
a solution of 10 (10.05 g, 59.77 mmol) in 100 mL of DMF,
and the mixture was heated at 110°C for 2 h, cooled to
50°C, and 7c (22.29 g, 135.4 mmol) was added while stir-
ring. After 5 days the mixture was cooled to RT, filtered
through Celite, and concentrated in vacuo. The resulting
brown oil was extracted with MeOH:CH2Cl2 (70:30,
250 mL) containing 20 mL of conc. HCl. After concentra-
tion the mixture was diluted with H2O (250 mL) and treated
with satd. aq. NaHCO3. After extraction with EtOAc (3 ×
100 mL), the organic layer was washed with H2O and satd.
aq. NaCl. The brown oil (11.85 g, 77%) was used for the
Melting points were taken in capillary tubes and have
1
been corrected. The H and 13C NMR spectra were obtained
at room temperature (RT) on a 400 MHz spectrometer using
CDCl3 as solvent with SiMe4 (δ = 0) as internal standard,
except as noted. The MS was carried out in house, at the
Washington University Mass Spectrometry Resource and at
the Nebraska Center for Mass Spectrometry using the FAB
technique in 3-nitrobenzyl alcohol matrices (HR = high res-
olution). A syringe infusion pump was used to control the
addition rates in the cyclization reactions.
p-Bis(2-hydroxyethoxy)benzene (8a)
1
next step without further purification. H NMR, δ (ppm):
A solution of 7c (52.5 g, 320 mmol) in n-BuOH (150 mL)
was added dropwise to a refluxing solution of hydroquinone
(11.0 g, 101 mmol), NaOH (8.20 g, 200 mmol), sodium
dithionite (40 mg), and n-BuOH (300 mL). The solution was
refluxed for 15 h under N2, and more NaOH (2.90 g,
72.5 mmol) was added and refluxing was continued for 15 h.
The reaction mixture was cooled, filtered, and concentrated
in vacuo to remove solvent and excess 7c. The residue was
dissolved in MeOH:CH2Cl2 (1:1 v:v, 500 mL), treated with
conc. HCl (5 mL) and stirred for 4 h at RT to hydrolyze the
THP ether. The solution was neutralized with NaHCO3. The
organic layer was dried (Na2SO4) and evaporated to give the
crude product (17.0 g, 85%), which was recrystallized from
EtOAc: mp 105–107°C; this compound is commercially
available.
3.89 (s, 3H), 3.96 (t, J = 4.4 Hz, 4H), 4.07 (t, J = 4.4 Hz,
4H), 6.65 (t, J = 2.2 Hz, 1H), and 7.17 (d, J = 2.2 Hz, 2H).
13C NMR, δ (ppm): 52.30, 61.16, 69.48, 106.86, 107.98,
131.90, 159.56, and 166.72 (8 peaks as required).
Methyl 3,5-bis(2-chloroethoxy)benzoate (13a)
A solution of methyl 3,5-bis(2-hydroxyethoxy)benzoate
(10.98 g, 42.85 mmol) in C6H6 (275 mL) was refluxed for
30 min using a Dean–Stark apparatus. At RT pyridine
(7.0 mL, 87 mmol, 2.0 equiv.) was added along with SOCl2
(6.4 mL, 88 mmol) over 1 h. After 48 h at reflux, the mix-
ture was cooled to RT and the salt removed by decantation,
washed with C6H6, and the organic layers were combined
and then washed sequentially with H2O, dil. HCl, and satd.
aq. NaCl. Evaporation resulted in an oil; passage through a
short SiO2 column using CHCl3:EtOAc (20:1) gave 13a
(11.10 g, 88%), an oil, which crystallized: mp 68.2–69.4°C.
1H NMR, δ (ppm): 3.82 (t, J = 5.8 Hz, 4H), 3.90 (s, 3H),
4.25 (t, J = 5.8 Hz, 4H), 6.70 (t, J = 2.4 Hz, 1H), and 7.21
(d, J = 2.4 Hz, 2H). 13C NMR, δ (ppm): 41.70, 52.26, 68.23,
107.06, 108.33, 132.20, 159.18, 166.37 (8 peaks as re-
quired). Anal. calc. for C12H14Cl2O4: C 49.16, H 4.81;
found: C 49.48, H 4.77.
p-Bis[2-(2′-hydroxyethoxy)ethoxy]benzene (8b)
Application of the above procedure using 7b on twice the
scale afforded 43.6 g (76%) of colorless solid after
1
recrystallization from EtOAc: mp 74.5–75.5°C. H NMR, δ
(ppm): 2.75 (s, 2H), 3.6–4.4 (m, 16H), 6.85 (s, 4H). Anal.
calcd. for C14H22O6: C 58.72, H 7.75; found: C 58.64, H
7.78.
p-Bis(2-chloroethoxy)benzene (9a)
The compound SOCl2 (223.0 g, 1.874 mol) was added
very slowly to a solution of 8a (148.66 g, 750 mmol),
pyridine (150 mL), and toluene (450 mL). The solution was
refluxed for 24 h, cooled, and the precipitate was extracted
with toluene (2 × 150 mL). The extract was washed with
H2O (200 mL), dried (Na2SO4), and evaporated to produce
p-(2-Hydroxyethoxy)benzyloxybenzene (17)
NaH (1.84 g, 46.0 mmol, 60% in mineral oil) was added
to a solution of 14 (8.02 g, 40.1 mmol) in DMF (60 mL). At
50°C, 7c (7.45 g, 45.3 mmol) was added, and the mixture
was stirred for 30 h at 50°C. After filtration, DMF was
evaporated, and the oil was diluted with MeOH:CH2Cl2 (6:2,
2 P.B. Balanda and H.W. Gibson. Unpublished results.
© 1998 NRC Canada

1434
Can. J. Chem. Vol. 76, 1998
150 mL) containing conc. HCl (5 mL). After 6 h, the solvent
was removed, and the mixture was diluted with H2O. The
EtOAc extract was dried (Na2SO4) and evaporated to give a
white solid, which was recrystallized from EtOH to give 17
(10.02 g, 100%), a white solid: mp 104.2–106.0°C, lit. (22)
mp 103.5–104.5. 1H NMR, δ (ppm): 3.90 (m, 2H), 4.00 (t, J =
4.4 Hz, 2H), 5.00 (s, 2H), 6.86 (AB q, J = 9.2 Hz, 4H), and
7.36 (m, 5H). 13C NMR, δ (ppm): 61.45, 69.80, 70.59,
115.49, 115.81, 127.40, 127.83, 128.48, 137.14, 152.88, and
153.20 (11 peaks as required).
108.12, 115.65, 115.77, 127.46, 127.86, 128.52, 131.90,
137.25, 153.06, 153.15, 159.72, and 166.74 (19 peaks as re-
quired). MS (FAB), m͞z (rel. int.): 708 [M+, 100%], 677
[(M – OCH3)+, 76%], and 586 [(M – OCH3 – CH2C6H5)+,
12%]. HRFAB, m͞z, calcd. for C42H44O10 [M]+: 708.2934;
found: 708.2955 (error 2.8 ppm).
Methyl 3,5-bis[8-(p-benzyloxyphenoxy)-3,6-
dioxaoctyloxy]benzoate (15c)
A procedure similar to that used for 15b was utilized to
prepare 15c (63%), which crystallized slowly to give a light
1
yellow solid: mp 61–63°C. H NMR, δ (ppm): 3.74 (m, 8H),
p-(2-Chloroethoxy)benzyloxybenzene (18)
Pyridine (7.6 mL, 94 mmol) and then SOCl2 (6.9 mL,
95 mmol) were added to a solution of 17 (9.53 g,
39.0 mmol) in C6H6 (150 mL). After 48 h at reflux, the mix-
ture was cooled to RT, and salt was removed by decantation,
washed with C6H6, and the organic layers were combined,
washed with H2O, dil. HCl, and satd. aq. NaCl. Evaporation
gave a light yellow solid, which was recrystallized from
EtOH to give 18 (8.38 g, 82%), a white solid: mp 69.7–
3.84 (m, 8H), 3.87 (s, 3H), 4.07 (t, J = 4.8 Hz, 4H), 4.13 (t,
J = 4.8 Hz, 4H), 6.69 (s, 4H), 6.70 (t, J = 2.2 Hz, 1H), 6.86
(AB q, J = 9.2 Hz, 8H), 7.19 (d, J = 2.2 Hz, 2H), and 7.35
(m, 10H). 13C NMR, δ (ppm): 52.16, 67.68, 68.00, 69.58,
69.86, 70.58, 70.79, 70.84, 106.86, 107.99, 115.71, 115.56,
127.42, 127.81, 128.48, 131.84, 137.22, 153.05, 153.08,
159.71, and 166.70 (21 peaks as required). MS (FAB), m͞z
(rel. int.): 819.4 [(M + Na)+, 5%], 796.4 (M+, 85%), 765.4
[(M – OCH3)+, 42%], 706.4 [(M – COOCH3)+, 8%], and 674
[(M – OCH3 – CH2C6H5)+, 5%], 76 [100%]. HRFAB, m͞z,
calcd. for C46H52O12 [M]+: 796.3459; found: 796.3476 (error
2.2 ppm). Anal. calc. for C46H52O12: C 69.33, H 6.58; found:
C 69.48, H 6.63.
1
71.2°C. H NMR, δ (ppm): 3.75 (t, J = 5.8 Hz, 2H), 4.14 (t,
J = 5.8 Hz, 2H), 4.99 (s, 2H), 6.87 (AB q, J = 9.2 Hz, 4H),
and 7.37 (m, 5H). 13C NMR, δ (ppm): 41.97, 68.79, 70.57,
115.83, 115.89, 127.40, 127.86, 128.49, 137.12, 152.44, and
153.46 (11 peaks as required). Anal. calc. for C15H15ClO2: C
68.57, H 5.75; found: C 68.66, H 5.78.
Methyl 3,5-bis[11-(p-benzyloxyphenoxy)-3,6,9-
oxaundecyloxy]benzoate (15d)
Methyl 3,5-bis[2-(p-benzyloxyphenoxyethoxy]benzoate (15a)
A procedure similar to that used for 15b was utilized to
prepare 15d (64%), an oil. 1H NMR, δ (ppm): 3.70 (m,
16H), 3.82 (m, 8H), 3.87 (s, 3H), 4.06 (t, J = 4.8 Hz, 4H),
4.12 (t, J = 4.8 Hz, 4H), 4.99 (s, 4H), 6.68 (t, J = 2.4 Hz,
1H), 6.86 (AB q, J = 9.2 Hz, 8H), 7.19 (d, J = 2.4 Hz, 2H),
and 7.36 (m, 10H). 13C NMR (ppm): 52.19, 67.68, 67.98,
69.54, 69.80, 70.59, 70.63, 70.74, 70.79, 106.84, 107.97,
115.54, 115.71, 127.43, 127.82, 128.48, 131.82, 137.22,
153.03, 153.08, 159.70, and 166.72 (22 peaks; theory 23).
MS (FAB), m͞z (rel. int.): 907 [(M + Na)+, 2%], 884 [M+,
41%], 853 [(M – OCH3)+ 32%], and 762 [(M – C8H10O)+,
3%], 225 (56%), 200 (100%); HRFAB, m͞z, calcd. for
C50H60O14 [M]+: 884.3983, found: 884.3982 (error 0.1 ppm).
Method A: NaH (316 mg, 13.2 mmol,) was added to a solu-
tion of 10 (1.02 g, 6.07 mmol) in DMF (60 mL), and the so-
lution was stirred for 1 h at 110°C. At 65°C, 18 (3.30 g,
12.6 mmol) was added as a solid, and the mixture was
stirred for 48 h. After filtration, DMF was evaporated, and
the oil was subjected to column chromatography (SiO2) with
CHCl3:EtOAc (20:1). The resultant oil upon trituration with
hexane gave 15a, a white solid (2.27 g, 60%): mp 79.4–
1
81.7°C. H NMR, δ (ppm): 3.90 (s, 3H), 4.28 (m, 8H), 5.02
(s, 4H), 6.76 (brs, 1H), 6.90 (AB q, 8H, J = 9.2 Hz, 8H),
7.25 (d, J = 2.0 Hz, 2H), and 7.37 (m, 1 OH). 13C NMR, δ
(ppm): 52.25, 66.95, 67.11, 70.66, 107.15, 108.22, 115.78,
115.86, 127.44, 127.87, 128.52, 132.02, 137.19, 152.878,
153.33, 159.66, and 166.69 (17 peaks as required). Anal.
calc. for C38H36O8: C 73.53, H 5.85; found: C 73.14, H 6.13.
Methyl 3,5-bis[2-(p-hydroxyphenoxy)ethoxy]benzoate
(16a)
A solution of 15a (1.08 g, 1.74 mmol) in CHCl3:MeOH
(1:1, 40 mL) containing Pd͞C (100 mg) was subjected to
hydrogenolysis at 60 psi for 48 h, filtered, and concentrated
to give an oil, which was purified by SiO2 column chroma-
tography. Addition of CHCl3 to the resulting oil gave 16a
Method B: The same except using 1.82 g (13.2 mmol) of
K2CO3 instead of NaH at 80°C; 3.03 g (80%) of 15a.
Methyl 3,5-bis[5-(p-benzyloxyphenoxy)-3-
oxapentyloxy]benzoate (15b)
1
(0.96 g, 90%), a white solid: mp 130.3–131.9°C. H NMR, δ
NaH (680 mg, 17 mmol, 60% in mineral oil) was added to
a stirred solution of 14 (3.24 g, 16.2 mmol) in DMF
(50 mL). After 30 min a solution of 13b (2.95 g, 7.74 mmol)
in DMF (20 mL) was added, and the mixture was stirred for
2 days at RT, filtered, and concentrated to give an oil, which
was purified via flash SiO2 chromatography using Et2O to
give 3.38 g (62%) of 15b, a white solid, which was
recrystallized from EtOAc:pet. ether (bp 39–59°C): mp
(ppm): 3.84 (s, 3H), 4.20 (m, 4H), 4.32 (m, 4H), 6.76 (AB q,
J = 9.2 Hz, 8H), 6.90 (t, J = 2.2 Hz, 1H), 7.12 (d, J =
2.2 Hz, 2H), and 8.95 (s, 2H). 13C NMR, δ (ppm): 52.32,
66.67, 66.98, 106.30, 107.58, 115.50, 115.74, 131.65,
151.04, 151.38, 159.61, and 165.83 (12 peaks, as required).
Anal. calc. for C24H24O8·H2O: C 62.87, H 5.72; found: C
62.72, H 5.36.
1
60.9–62.4°C. H NMR, δ (ppm): 3.88 (s, 3H), 3.90 (m, 8H),
4.10 (t, J = 4.8 Hz, 4H), 4.16 (t, J = 4.8 Hz, 4H), 5.00 (s,
4H), 6.71 (t, J = 2.4 Hz, 1H), 6.87 (AB q, J = 9.2 Hz, 8H),
7.20 (d, J = 2.4 Hz, 2H), and 7.37 (m, 10H). 13C NMR, δ
(ppm): 52.22, 67.79, 68.13, 69.76, 70.06, 70.64, 106.93,
Methyl 3,5-bis[5-(p-hydroxyphenoxy)-3-
oxapentyloxy]benzoate (16b)
A solution of 15b (2.58 g, 3.64 mmol) in CHCl3:EtOAc
(1:1, 30 mL) was subjected to hydrogenolysis (60 psi) at RT
© 1998 NRC Canada

Gibson et al.
1435
in the presence of 10% Pd͞C (150 mg) for 10 h, filtered, and
Bis(5-carbomethoxy-1,3-phenylene)-bis(p-phenylene)-42-
crown-12 (11b)
1
concentrated in vacuo to give 16b (1.9 g, 98%), an oil. H
NMR, δ (ppm): 3.87 (m, 11 H), 4.07 (m, 8H), 6.55 (t, J =
2.2 Hz, 1 H), 6.72 (s, 8H), and 7.15 (d, J = 2.2 Hz, 2H). 13C
NMR, δ (ppm): 52.33, 67.59, 68.09, 69.63, 69.98, 107.06,
108.02, 115.85, 116.07, 131.60, 150.05, 152.36, 159.53, and
167.04 (14 peaks as required). MS (FAB), m͞z (rel. int.):
528 [M+, 100%], 497 [(M – OCH3)+, 49%], and 420 (M+ –
CH3 – C6H4OH, 16%); HRFAB, m͞z, calcd. for C28H32O10
[M]+: 528.1995, found: 528.1981 (error 2.7 ppm).
A solution of 16b (1.91 g, 3.61 mmol) and 13b (1.38 g,
3.62 mmol) in DMF (total volume 20 mL) was added via a
syringe pump at 1.5 mL͞h to a suspension of K2CO3
(5.20 g, 37.6 mmol) and tetra(n-butyl)ammonium iodide
(20 mg) in DMF (175 mL) at 110°C. After complete addi-
tion, the mixture was stirred vigorously at 110°C for 5 days,
cooled, and evaporated. The residue was dissolved in
CH2Cl2 and filtered. Removal of CH2Cl2 followed by flash
column (SiO2) chromatography eluting with Et2O gave pure
11b (700 mg, 23%): mp 140–142°C. 1H NMR, δ (ppm): 3.89
(m, 22H), 4.08 (t, J = 4.6 Hz, 8H), 4.14 (t, J = 4.6 Hz, 8H),
6.71 (t, J = 2.2 Hz, 2H), 6.82 (s, 8H), and 7.19 (d, J =
2.2 Hz, 4H). 13C NMR, δ (ppm): 52.19, 67.84, 68.16, 69.65,
69.97, 107.18, 108.09, 115.64, 131.81, 153.05, 159.70, and
166.72 (12 peaks as required). MS (FAB), m͞z (rel. int.):
859.1 [(M + Na)+, 14%], 836.1 (M+, 100%), and 805.1 [(M
– OCH3)+, 16%]; HRFAB, m͞z, calcd. for C44H52O16 [M+]:
836.3255, found 836.3286 (error 3.6 ppm).
Methyl 3,5-bis[8-(p-hydroxyphenoxy)-3-,6-
dioxaoctyloxy]benzoate (16c)
A procedure similar to that used for 16b was utilized to
1
prepare 16c, an oil (99%). H NMR (DMSO), δ (ppm): 3.58
(m, 8H), 3.68 (t, J = 4.6 Hz, 4H), 3.73 (t, J = 4.6 Hz, 4H),
3.81 (s, 3H), 3.94 (t, J = 4.6 Hz, 4H), 4.12 (t, J = 4.6 Hz,
4H), 6.68 (AB q, J = 9.2 Hz, 8H), 6.80 (t, J = 2.2 Hz, 1 H),
7.05 (d, J = 2.2 Hz, 2H), and 8.89 (s, 2H). 13C NMR
(DMSO), δ (ppm): 52.28, 67.51, 67.60, 68.82, 69.12, 69.90,
69.95, 106.15, 107.45, 115.36, 115.69, 131.57, 151.20,
151.24, 159.69, and 165.87 (16 peaks as required). MS
(FAB), m͞z (rel. int.): 639 [(M + Na)+, 5%], 616 [M+, 34%],
and 585 [(M – OCH3)+, 20%), 163 (100%); HRFAB, m͞z,
calcd. for C32H40O12 [M]+: 616.2520, found: 616.2511 (error
1.4 ppm).
Bis(5-carbomethoxy-1,3-phenylene)-bis(p-phenylene)-54-
crown-16 (11c)
A procedure similar to that used for 11b was utilized to
1
prepare 11c (18%), a white solid: mp 102.9–104.3°C. H
NMR, δ (ppm): 3.73 (m, 16H), 3.83 (m, 8H), 3.89 (s, 6H),
4.05 (t, J = 4.8 Hz, 8H), 4.12 (t, J = 4.8 Hz, 8H), 6.70 (t, J =
2.2 Hz, 2H), 6.81 (s, 8H), and 7.18 (d, J = 2.2 Hz, 4H). 13C
NMR, δ (ppm): 52.19, 67.76, 68.07, 69.60, 69.87, 70.83,
70.91, 106.92, 108.06, 115.58, 131.84, 153.05, 159.74, and
166.72 (14 peaks as required). MS (FAB), m͞z (rel. int.):
1012.9 (M+, 100%), 981.9 [(M – OCH3)+, 15%], and 950.9
[(M – 2OCH3)+, 12%]; HRFAB, m͞z, calcd. for C52H69O20
[M + H]+ 1013.4382; found 1013.4399 (error 1.6 ppm).
Methyl 3,5-bis[11-(p-hydroxyphenoxy)-3,6,9-
oxaundecyloxy]benzoate (16d)
A procedure similar to that used for 16b was utilized to
prepare 16d, an oil (98%). 1H NMR, δ (ppm): 3.69 (m,
16H), 3.79 (m, 8H), 3.87 (s, 3H), 3.96 (t, J = 4.8 Hz, 4H),
4.00 (t, J = 4.8 Hz, 4H), 6.56 (t, J = 2.4 Hz, 1 H), 6.65 (s,
2H), 6.69 (AB q, J = 9.2 Hz, 8H), 7.13 (d, J = 2.4 Hz, 2H).
13C NMR, δ (ppm): 52.29, 67.50, 67.99, 69.57, 69.78, 70.52,
70.56, 106.644, 108.06, 115.67, 116.06, 131.62, 150.36,
152.28, 159.61, and 167.04 (16 peaks; theory 18). MS
(FAB), m͞z (rel. int.): 704 [(M + Na)+, 8%], 391 [(M –
COOCH3 – 2HOC6H4 – OCH2CH2)+, 80%], 167 (100%);
HRFAB, m͞z, calcd. for C34H48O14 [M + Na]+: 703.2941,
found: 703.2952 (error 1.4 ppm).
Bis(5-carbomethoxy-1,3-phenylene)-bis(p-phenylene)-66-
crown-20 (11d)
A procedure similar to that used for 11b was utilized to
prepare 11d (19%), a white solid: mp 77.5–79.5°C. 1H
NMR, δ (ppm): 3.69 (m, 32H), 3.82 (m, 16H), 3.88 (s, 6H),
4.04 (t, J = 4.8 Hz, 8H), 4.12 (t, J = 4.8 Hz, 8H), 6.69 (t, J =
2.2 Hz, 2H), 6.81 (s, 8H), and 7.18 (d, J = 2.2 Hz, 4H). 13C
NMR, δ (ppm): 52.17, 69.72, 68.00, 69.51, 69.77, 70.64,
70.74, 70.80, 106.86, 107.98, 115.51, 131.81, 153.01,
159.71, and 166.70 (15 peaks; theory 16). MS (FAB), m͞z
(rel. int.): 1211 [(M + Na)+, 1%], 1188.4 (M+, 100%),
1173.3 [(M – CH3)+, 5%], and 1157.4 [(M – OCH3)+, 16%],
1125 [(M – 2OCH3)+, 8%]; HRFAB, m͞z, calcd. for
C60H85O24 [M + H]+: 1189.5431; found 1189.5440 (error
0.8 ppm).
3,5-Bis(vinyloxy)benzoic acid (19) from attempted
synthesis of 11a
A solution of 13a (814.1 mg, 2.780 mmol) and 16a
(1.16 g, 2.63 mmol) in DMF (total volume = 12 mL) was
added via a syringe pump at 2.0 mL͞h to a suspension of
NaH (1.2 g, 30 mmol, 60% in mineral oil) in DMF (175 mL)
at 110°C. After addition, the mixture was stirred at 85°C for
4 days, cooled, evaporated, treated with CHCl3, and filtered.
Removal of CHCl3 followed by flash SiO2 column chroma-
tography eluting with CHCl3:EtOAc (20:1) gave pure 19
1
(110 mg, 19%): mp 115.7–117.5°C. H NMR, δ (ppm): 4.57
We have synthesized three new functionalized cyclic
tetraphenylene polyethers, namely bis(5-carbomethoxy-1,3-
phenylene)-bis(p-phenylene)-(3x + 6)crown-x, where x = 12,
16, and 20 (11b–11d) with ring sizes of 42, 54, and 66 at-
oms in 17–24% yields by [1 + 1] condensations of
dichlorides 13b–13d with the corresponding bisphenols
16b–16d. These macrocycles do not complex with second-
(dd, J = 6.0 and 2.4 Hz, 1H), 4.87 (dd, J = 13.6 and 2.0 Hz,
1H), 6.66 (dd, J = 13.6 and 2.0 Hz, 1H), 6.91 (t, J = 2.2 Hz,
1H), and 7.46 (d, J = 2.2 Hz, 2H). 13C NMR, δ (ppm):
97.04, 111.42, 112.75, 131.66, 147.09, 157.86, and 170.71 (7
peaks as required). Anal. calc. for C11H10O4·1͞4 H2O: C
62.70, H 5.02; found: C 62.80, H 4.93.
© 1998 NRC Canada

1436
Can. J. Chem. Vol. 76, 1998
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We acknowledge support from the National Science Foun-
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here. Some mass spectrometry data were provided by the
Nebraska Center for Mass Spectrometry, Department of
Chemistry, University of Nebraska, and by the Washington
University Mass Spectrometry Resource, an NIH Research
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© 1998 NRC Canada