Synthesis and structure of cyclic oligo(p-phenylene oxide)s, -(C 6H4O)n- (n = 6-10)

Article abstract of DOI:10.1021/jo0609982

Stepwise growth of oligo(p-phenylene oxide)s and cyclization via the Ullmann coupling reaction by using CuI/N,N-dimethylglycine afforded cyclic oligo(p-phenyleneoxide)s, -(C₆H₄O)_n-(n = 6-10). The structure of the new cyclophanes was determined by X-ray crystallography, which revealed that they have planar or slightly bent structures with diameters of 1.0-1.5 nm.

Full text of DOI:10.1021/jo0609982

Synthesis and Structure of Cyclic
the cyclic oligo(p-phenylene oxide)s, -(C6H4O)n-, with suit-
able ring size for the host-guest complexation. Vo¨gtle
Oligo(p-phenylene oxide)s,
conducted
cop-
-(C6H4O)n- (n ) 6-10)
per-catalyzed Ullmann coupling of 4-bromophenol and obtained
a mixture of the cyclic oligo(p-phenylene oxide)s with n ) 5-9.8
Recently, Ma has reported that the Ullmann coupling reaction
using CuI/N,N-dimethylglycine catalyst enabled coupling of phen-
ols with aryl iodides under mild conditions.9 Ullmann coupling
catalyzed by Cu2O in the presence of Cs2CO3 and K3PO4 (with
aryl iodide and bromides, respectively) and trans-1,2-bis(2′-
pyridylidenamino)cyclohexane has also been found by Taillefer.10
Herein, we report application of these new Ullmann coupling
reactions to selective synthesis of the cyclic oligo(p-phenylene
oxide)s.
Daisuke Takeuchi, Itaru Asano, and Kohtaro Osakada*
Chemical Resources Laboratory (Mail Box R1-03), Tokyo
Institute of Technology, 4259 Nagatsuda, Midori-ku,
Yokohama 226-8503, Japan
kosakada@res.titech.ac.jp
ReceiVed May 14, 2006
Scheme 1 shows two routes for synthesis of linear phenylene
oxide tetramer terminated with two OH groups L-4-OH.
Analogous penta(phenylene oxide), HOC6H4O(C6H4O)3C6H4-
OH, was prepared by Tashiro by using a similar Ullmann
coupling reaction by using CuCl (80-150 mol %) at 80 °C.11
A 2:1 coupling reaction of 4-methoxymethoxyphenol formed
by protection of a hydroxy group of dihydroquinone12 and 4,4′-
dibromodiphenyl ether in the presence of CuI/N,N-dimethylg-
lycine resulted in formation of a linear tetramer L-4-OMOM
in 63% yield. Removal of the methoxymethyl group with HCl
gives L-4-OH in 98% yield (Scheme 1, method A). Coupling
of 4-methoxyphenol and 4,4′-diiododiphenyl ether, synthesized
by the reaction of diphenyl ether with N-iodosuccinimide,13
forms L-4-OMe in 86% yield. Subsequent demethylation by
BBr3 yields L-4-OH in 90% yield (Scheme 1, method B).
An equimolar reaction of L-4-OH with 4,4′-diiododiphenyl
ether in the presence of the Cu reagent afforded the cyclic hexa-
mer, C-6 (eq 1). Table 1 summarizes the results of the cycliza-
Stepwise growth of oligo(p-phenylene oxide)s and cyclization
via the Ullmann coupling reaction by using CuI/N,N-dimethyl-
glycineaffordedcyclicoligo(p-phenyleneoxide)s, -(C6H4O)n-
(n ) 6-10). The structure of the new cyclophanes was deter-
mined by X-ray crystallography, which revealed that they have
planar or slightly bent structures with diameters of 1.0-1.5 nm.
Various cyclophanes composed of the aromatic groups attached
to OH or OR groups have been investigated1 partly because the
electron-rich aromatic rings are able to form a complex with
electron-deficient guest molecules such as C60. Attractive inter-
action between hydroquinones and C60, forming a 3:1 complex,
was observed in the solid state.2 Fully aromatic crown ethers are
also expected to exhibit attractive interaction with electron-defi-
cient molecules and to form a host-guest complex, although their
synthetic examples are rare and the yield is very low.3 Quite
recently, Gibb reported templated synthesis of cyclic oligo(m-
phenylene oxide)s.4,5
Although examples of cyclic oligo(p-phenylene sulfide)s are
known,6,7 there have been few reports on efficient synthesis of
(1) (a) Bo¨hmer, V. Angew. Chem., Int. Ed. Engl. 1995, 34, 713-345.
(b) Calixarene 2001; Asfari, Z., Bo¨hmer, V., Harrowfield, J., Ed.; Kluwer
Academic Publishers: Dordrecht, 2001.
(2) Ermer, O. HelV. Chim. Acta 1991, 74, 1339-1351.
(3) Kime, D. E.; Norymberski, J. K. J. Chem. Soc., Perkin Trans. 1 1977,
1048-1052.
tion. The reaction of 4,4′-diiododiphenyl ether with L-4-OH in
dioxane for 168 h did not form the cyclic product (run 1),
(4) Li, X.; Upton, T. G.; Gibb, C. L. D.; Gibb, B. C. J. Am. Chem. Soc.
2003, 125, 650-651.
(8) Franke, J.; Vo¨gtle, F. Tetrahedron Lett. 1984, 25, 3445-3448.
(9) Ma, D.; Cai, Q. Org. Lett. 2003, 5, 3799-3802.
(10) (a) Cristau, H.-J.; Cellier, P. P.; Hamada, S.; Spindler, J.-F.; Taillefer,
M. Org. Lett. 2004, 6, 913-916. (b) Ouali, A.; Spindler, J.-F.; Cristau,
H.-J.; Taillefer, M. AdV. Synth. Catal. 2006, 348, 499-505.
(11) Tashiro, M.; Yoshiya, H.; Fukata, G. Org. Prep. Proc. Int. 1981,
13, 87-92.
(12) Aoki, K.; Takahashi, M.; Hashimoto, M.; Okuno, T.; Kurata, K.;
Suzuki, M. Biosci. Biotechnol. Biochem. 2002, 66, 1915-1924.
(13) Castanet, A.-S.; Colobert, F.; Broutin, P.-E. Tetrahedron Lett. 2002,
43, 5047-5048.
(5) Recent examples of synthesis of cyclic (m-phenylene oxide)s: (a)
Katz, J. L.; Feldman, M. B.; Conry, R. R. Org. Lett. 2005, 7, 91-94. (b)
Yang, F.; Yan, L.; Ma, K.; Yang, L.; Li, J.; Chen, L.; You, J. Eur. J. Org.
Chem. 2006, 1109-1112.
(6) Miyatake, K.; Yokoi, Y.; Yamamoto, K.; Tsuchida, E.; Hay, A. S.
Macromolecules 1997, 30, 4502-4503.
(7) Examples on N-bridged similar macrocycles: (a) Hauck, S. I.;
Lakshmi, K. V.; Hartwig, J. Org. Lett. 1999, 1, 2057-2060. (b) Ito, A.;
Ono, Y.; Tanaka, K. Angew. Chem., Int. Ed. 2000, 39, 1072-1073. (c)
Fukushima, W.; Kanbara, T.; Yamamoto, T. Synlett, 2005, 2931-2934.
10.1021/jo0609982 CCC: $33.50 © 2006 American Chemical Society
Published on Web 10/06/2006
8614
J. Org. Chem. 2006, 71, 8614-8617

SCHEME 1. Synthesis of L-4-OH
TABLE 1. Synthesis of Cyclic Oligo(p-phenylene oxide)s
reactanta
reaction
run
HO-Ar-OH
I-Ar′-I
catalystc
solvent
HO-Ar-OH (mM)
T (°C)
time (h)
productb
no reaction
C-6
C-6
C-6
C-6
no reaction
no reaction
C-6
C-7
C-8
C-9
C-10
1
2
3
4
5
L-4-OH
L-4-OH
L-4-OH
L-4-OH
L-4-OH
L-4-OH
L-4-OH
L-4-OH
L-6-OH
L-6-OH
L-6-OH
L-6-OH
L-2-I
L-2-I
L-2-I
L-2-I
L-2-I
L-2-I
L-2-I
L-2-I
L-1-I
L-2-I
L-3-I
L-4-I
A
A
A
A
B
A
A
A
A
A
A
A
dioxane
DMF
DMF
DMSO
DMF
C2H2Cl4
DMF
DMF
DMF
DMF
DMF
50
25
5
25
25
30
25
25
5
90
100
100
100
110
100
100
100
100
100
100
100
168
22
44
20
64
148
36
36
20
20
18
16
(17)
(8.1)
(11)
(11)
6d
7d
8e
9
(8.9)
(19)
(20)
(27)
(21)
10
11
12
5
5
5
DMF
a HO-Ar-OH (1.0 mmol) and I-Ar′-I (1.0 mmol) were used as the reactants. b Yields are in parentheses. c A: CuI (0.2 mmol), Me2NCH2COOH‚HCl (0.6
mmol), Cs2CO3 (4.0 mmol). B: Cu2O (0.05 mmol), trans-1,2-bis(2′-pyridylidenamino)cyclohexane (0.2 mmol), Cs2CO3 (4.0 mmol), MS3A (60 mg). d Me4NBr
was added. e Et4NI was added.
probably due to low solubility of L-4-OH in dioxane. The reac-
tion with L-4-OH at 100 °C, 22 h, in a DMF solution (25 mM)
proceeds more smoothly to give a mixture of the cyclic and
linear oligo(p-phenylene oxide)s. After removal of DMF by
evaporation, extraction from the residue with CHCl3 afforded
analytically pure C-6 in 17% yield (run 2). The reaction with
low concentration of L-4-OH (5 mM) and that in DMSO also
produced C-6 in 8.1% (runs 3 and 4). Analogous cyclization
by condensation using Cu2O/trans-1,2-bis(2′-pyridylidenamino)-
cyclohexane produced the cyclic oligomer in 11% yield (run
5). Addition of quaternary ammonium salts, which may act as
potential templates for the cyclization, did not improve yield
of the desired product (runs 6-8).
Cyclic oligo(p-phenylene oxide)s with larger ring sizes were
also synthesized. Linear hexamer L-6-OH was synthesized by
the coupling of 4-hydroxy-4′-methoxymethoxydiphenyl ether with
4,4′-diiododiphenyl ether in the presence of CuI/N,N-dimethylgly-
cine in DMF followed by removal of the MOM group by treat-
ment with HCl. The reaction of L-6-OH with 1,4-diiodobenzene
in the presence of the copper catalyst produced the cyclic hep-
tamer, C-7, in 26% yield (run 9). L-6-OH underwent cyclizative
coupling with L-2-I, L-3-I, and L-4-I to afford C-8, C-9, and
C-10 in the respective yields of 20, 27, and 21% after simple
evaporation of DMF and extraction with CHCl3 (runs 10-12).
The NMR and MS spectra of C-6-C10 are consistent with
1
the cyclic structure (Scheme 2). For example, the H NMR
spectrum of C-9 shows one singlet signal at δ 6.96, which is
assigned to the phenylene hydrogens. The 13C{1H} NMR
spectrum of C-9 shows signals at δ 119.8 and 153.1 due to CH
and quaternary carbons, respectively. The FAB-MS spectrum
of C-9 shows a signal at 828.2348, which is in agreement with
the calculated molecular weight (828.2359).
Recrystallization of the cyclic oligo(p-phenylene oxide)s from
CH2Cl2/hexane or CHCl3/hexane affords single crystals suitable
for X-ray crystal structure analysis. ORTEP view of C-6-C-9
is shown in Figure 1. The crystals contain CH2Cl2 or CHCl3
molecules used in recrystallization. A Cl atom of the CH2Cl2
molecule exists at the center of the pore of C-6, while two
molecules are positioned outside of the macrocycle. A CHCl3
molecule is included within the bent macrocycle of C-7. C-8
and C-9 contain a CHCl3 molecule inside of the pore. The C-9
has an extra inside space, which is filled by a phenylene oxide
unit of another C-9 molecule. The neighboring phenylene planes
J. Org. Chem, Vol. 71, No. 22, 2006 8615

SCHEME 2. Synthesis of C-7-C-10
of C-6 are situated almost perpendicularly, while the neighboring
aromatic planes of C-7, C-8, and C-9 are twisted with smaller
angles. C-6 and C-8 have almost planar structure structures,
whereas C-7 and C-9 have bent structures due to an even-odd
effect. The 13C{1H} NMR spectra of C-6-C-9, however, show
a single signal, indicating that the phenylene planes rotate faster
than the NMR time scale in solution. The diameters of C-6 and
C-9 are estimated as approximately 1.0 and 1.5 nm.
In summary, we succeeded in synthesizing cyclic hexa- to deca-
(p-phenylene oxide)s by Ullmann coupling using CuI/N,N-di-
methylglycine. Structures of the cyclic hexa- to nona(p-phenyl-
ene oxide)s were determined by X-ray crystallography, which re-
vealed that they have planar or slightly bent structures with diam-
eters of 1.0-1.5 nm. The cyclic oligo(p-phenylene oxide)s, thus
formed, will be used as modules in supramolecular chemistry.
FIGURE 1. ORTEP views of cyclic oligo(p-phenylene oxide)s (a)
C-6, (b) C-7, (c) C-8, and (d) C-9 at the 30% ellipsoidal level.
Hydrogen atoms are omitted for clarity.
4,4′-Diiododiphenyl Ether. To a 100-mL round-bottomed flask
were added diphenyl ether (1.0 g, 5.9 mmol), N-iodosuccinimide
(2.8 g, 12 mmol), acetonitrile (20 mL), and trifluoroacetic acid (1
drop), and the mixture was refluxed for 4 h. Chloroform was added,
and the organic phase was washed with Na2S2O3 aq (1 time) and
water (2 times), which was dried over MgSO4. The volatiles were
evaporated, and the residue was recrystallized from chloroform/
hexane to obtain 4,4′-diiododiphenyl ether as a white solid (2.2 g,
5.2 mmol, 88% yield): 1H NMR (300 MHz, CDCl3, 25 °C) δ 7.63
(d, 2H, J ) 9.0 Hz), and 6.76 (d, 2H, J ) 9.0 Hz). 4,4′-Bis(4-
iodophenoxy)benzene (L-3-I) (90% yield) and 4,4′-bis(4-iodophe-
noxy)diphenyl ether (L-4-I) (90% yield) were prepared similarly.
L-3-I: 1H NMR (300 MHz, CDCl3, 25 °C) δ 7.61 (d, 4H, J ) 9.0
Hz), 6.99 (s, 4H), and 6.76 (d, 4H, J ) 9.0 Hz); 13C{1H} NMR
(75.5 MHz, CDCl3, 25 °C) δ 187.0, 157.7, 152.4 138.7 120.7, and
120.4. L-4-I: 1H NMR (300 MHz, CDCl3, 25 °C) δ 7.60 (d, 4H,
J ) 9.0 Hz), 6.99 (s, 8H), and 6.75 (d, 4H, J ) 9.0 Hz).
4,4′-Bis[4-(methoxymethoxy)phenoxy]diphenyl Ether. To a
100-mL round-bottomed flask were added 4-(methoxymethox)-
phenol (0.65 g, 3 mmol), 4,4′-dibromodiphenyl ether (0.33 g, 1
mmol), CuI (38 mg, 0.2 mmol), N,N-dimethylglycine hydrochloride
(84 mg, 0.6 mmol), Cs2CO3 (1.4 g, 4 mmol), and 1,4-dioxane (4
mL), and the mixture was stirred at 90 °C for 72 h. Ethyl acetate
was added, and the organic phase was washed three times with
water. After the phase was dried over MgSO4, volatiles were
evaporated, and the residue was chromatographed on silica gel
Experimental Section
4-(Methoxymethoxy)phenol. To a 100-mL round-bottomed
flask containing hydroquinone (4.0 g, 26 mmol), N,N-diisopropyl-
ethylamine (3.3 mL, 38 mmol), and acetonitrile (120 mL) was added
methoxymethyl chloride (2.3 g, 28 mmol) slowly at 0 °C. The
mixture was stirred at room temperature for 8 h, ethyl acetate was
added, and the mixtrue was washed with water (3 times). The
organic phase was dried over MgSO4, volatiles were evaporated,
and the residue was chromatographed on silica gel (ethyl acetate/
hexane ) 1:10) to obtain 4-(methoxymethoxy)phenol as a white
solid (1.5 g, 9.9 mmol, 38% yield): 1H NMR (300 MHz, CDCl3,
25 °C) δ 6.91 (d, 2H, J ) 9.0 Hz), 6.73 (d, 2H, J ) 9.0 Hz), 5.10
(s, 2H), 3.49 (s, 3H); 13C{1H} NMR (75.5 MHz, CDCl3, 25 °C) δ
151.2, 150.3, 118.0, 116.1, 95.5, and 55.9. 4-Hydroxy-4′-(meth-
oxymethoxy)diphenyl ether was prepared similarly from 4,4′-
dihydroxydiphenyl ether (38% yield): 1H NMR (300 MHz, CDCl3,
25 °C) δ 7.63 (d, 2H, J ) 9.0 Hz), 6.76 (d, 2H, J ) 9.0 Hz), 5.10
(s, 2H), 3.49 (s, 3H); 13C{1H} NMR (75.5 MHz, CDCl3, 25 °C) δ
152.9, 152.7, 151.4, 120.9, 119.3, 117.7, 116.3, 95.2, and 56.0.
8616 J. Org. Chem., Vol. 71, No. 22, 2006

(ethyl acetate/hexane ) 1:10) to obtain 4,4′-bis[4-(methoxymethox-
y)phenoxy]diphenyl ether as a white solid (0.9 g, 1.9 mmol, 63%
yield): 1H NMR (300 MHz, CDCl3, 25 °C) δ 7.03-6.92 (m, 16H),
5.14 (s, 4H), 3.49 (s, 6H); 13C{1H} NMR (75.5 MHz, CDCl3, 25
°C) δ 153.7, 153.1, 152.2, 120.1, 120.0, 119.7, 117.8, 95.3, and
56.2. 4,4′-Bis(4-methoxyphenoxy)diphenyl ether (L-4-OMe) (86%
yield), 4,4′-bis[4-{4-(methoxymethoxy)phenoxy}phenoxy]diphenyl
ether (L-6-OMOM) (82% yield), 1,4-diphenoxybenzene (94%
yield), and 4,4′-diphenoxydiphenyl ether (90% yield) were prepared
similarly. L-4-OMe: 1H NMR (300 MHz, CDCl3, 25 °C) δ 6.98-
6.92 (m, 12H), 6.87 (d, 4H, J ) 9.0 Hz), 3.80 (s, 6H); 13C{1H}
NMR (75.5 MHz, CDCl3, 25 °C) δ 155.8, 153.9, 152.9, 150.9,
120.3, 119.8, 119.2, 114.9, and 55.7. L-6-OMOM: 1H NMR (300
MHz, CDCl3, 25 °C) δ 7.03-6.91 (m, 24H), 5.14 (s, 4H), 3.50 (s,
6H); 13C{1H} NMR (75.5 MHz, CDCl3, 25 °C) δ 153.7, 153.3,
153.1, 152.8, 152.0, 120.1, 119.9, 119.9, 119.8, 119.5, 117.7, 95.1,
and 56.1. 1,4-Diphenoxybenzene: 1H NMR (300 MHz, CDCl3, 25
°C) δ 7.3-7.38 (m, 4H), 7.06-7.12 (m, 2H), and 6.98-7.02 (m,
8H); 13C{1H} NMR (75.5 MHz, CDCl3, 25 °C) δ 155.8, 153.9,
152.9, 150.9, 120.3, 119.8, 119.2, 114.9, and 55.7. 4,4′-Diphen-
oxydiphenyl ether: 1H NMR (300 MHz, CDCl3, 25 °C) δ 7.36-
7.30 (m, 4H), 7.11-7.06 (m, 2H), and 7.02-6.98 (m, 12H);
13C{1H} NMR (75.5 MHz, CDCl3, 25 °C) δ 157.8, 153.2, 152.5,
129.7, 123.0, 120.5, and 119.8.
Cyclic Hexa(p-phenylene oxide). To a 100-mL round-bottomed
flask were added 4,4′-(4-hydoxyphenoxy)diphenyl ether (101 mg,
0.25 mmol), 4,4′-diiododiphenyl ether (96 mg, 0.25 mmol), CuI (6
mg, 0.03 mmol), N,N-dimethylglycine hydrochloride (14 mg, 0.1
mmol), Cs2CO3 (0.33 g, 1.0 mmol), and DMF (10 mL), and the
mixture was stirred at 100 °C for 22 h. Volatiles were evaporated,
and the residue was extracted with chloroform, which was washed
three times with water and dried over MgSO4, and volatiles were
evaporated to obtain cyclic hexa(p-phenylene oxide) as a white solid
(30 mg, 0.044 mmol, 17% yield). The single crystals of cyclic hexa-
(p-phenylene oxide) were obtained by recrystallization from dichlo-
romethane/hexane. The macrocycles provided HRMS data that are
consistent with the molecular formula. Elemental analyses of C-7-
C-10, however, led to the results showing that they contain the
solvent in a nonstoichiometric ratio and that the formula based on
the analytical results may disagree with the crystallographic results.
It indicates that the crystals undergo elimination of the solvent in
part during drying them under vacuum and that the analytical results
are for the metastable solid containing partially eliminated solvent.
Formulas of C-7-C-10 containing CHCl3 are calculated from C/H
ratios only. C-6: 1H NMR (300 MHz, CDCl3, 25 °C) δ 6.85;
13C{1H} NMR (75.5 MHz, CDCl3, 25 °C) δ 154.0 and 120.0. Anal.
Calcd for C36H24O6: C, 78.25; H, 4.38. Found: C, 78.07; H, 4.51.
4,4′-Bis(4-hydroxyphenoxy)diphenyl Ether. A: From 4,4′-Bis-
[4-(methoxymethoxy)phenoxy]diphenyl Ether. To a 100-mL
round-bottomed flask were added 2-propanol (10 mL), dichlo-
romethane (10 mL), 4,4′-bis[4-(methoxymethoxy)phenoxy]diphenyl
ether (0.21 g, 0.44 mmol), and concd HCl (1 drop), and the mixture
was refluxed for 3 h. Volatiles were evaporated, and the residue
was washed with water to obtain 4,4′-bis(4-hydroxyphenoxy)-
diphenyl ether as a white solid (0.17 g, 0.44 mmol, 98% yield).
4,4′-Bis[4-(4-hydroxyphenoxy)phenoxy]diphenyl ether was pre-
pared similarly (99% yield): 1H NMR (300 MHz, DMSO-d6, 25
°C) δ 9.34 (s, 2H), 7.01-6.96 (m, 12H), 6.90 (d, 4H, J ) 9.0 Hz),
6.86 (d, 4H, J ) 9.0 Hz), and 6.75 (d, 4H, J ) 9.0 Hz); 13C{1H}
NMR (75.5 MHz, DMSO-d6, 25 °C) δ 154.9, 154.6, 153.8, 153.4
152.7 149.4, 121.4 120.9, 120.8, 120.6 119.6, and 117.2.
B: From 4,4′-Bis(4-methoxyphenoxy)diphenyl Ether. To a
100-mL round-bottomed flask containing 4,4′-bis(4-methoxyphen-
oxy)diphenyl ether (1.1 g, 2.65 mmol) and chloroform (60 mL)
was added BBr3 (dichloromethane solution (1.0 M), 15.5 mL)
dropwise over a period of 1 h at 0 °C. The mixture was gradually
warmed to room temperature and stirred for 2 h. The volatiles were
evaporated, and the residue was washed with water to afford 4,4′-
bis(4-hydroxyphenoxy)diphenyl ether as a white solid (0.95 g, 2.46
mmol, 97% yield): 1H NMR (300 MHz, DMSO-d6, 25 °C) δ 9.39
(s, 2H), 6.93 (d, 4H, J ) 9.0 Hz), 6.87 (d, 4H, J ) 9.0 Hz), 6.83
(d, 4H, J ) 9.0 Hz), and 6.73 (d, 4H, J ) 9.0 Hz); 13C{1H} NMR
(75.5 MHz, DMSO-d6, 25 °C) δ 154.8, 154.6, 153.0, 149.5, 121.3,
120.6, 119.6, and 117.1.
Other cyclic oligo(p-phenylene oxide)s were prepared similarly.
C-7: 1H NMR (300 MHz, CDCl3, 25 °C) δ 6.94; 13C{1H} NMR
(75.5 MHz, CDCl3, 25 °C) δ 153.3, and 120.0; HR MS (FAB+)
m/z calcd for C42H28O7 644.1835, found 644.1832. Anal. Calcd for
C42H28O7‚(CHCl3)0.11: C, 76.77; H, 4.30; Cl, 1.94. Found: C, 76.46;
H, 4.05, Cl, 1.02. C-8: 1H NMR (300 MHz, CDCl3, 25 °C) δ 6.93;
13C{1H} NMR (75.5 MHz, CDCl3, 25 °C) δ 153.0 and 120.0; HR
MS (FAB+) m/z calcd for C48H32O8 736.2097, found 736.2106.
Anal. Calcd for C48H32O8‚(CHCl3)1.7: C, 63.52; H, 3.61. Found:
C, 63.82; H, 3.61. C-9: 1H NMR (300 MHz, CDCl3, 25 °C) δ
6.953; 13C{1H} NMR (75.5 MHz, CDCl3, 25 °C) δ 153.3 and 120.0;
HR MS (FAB+) m/z calcd for C54H36O9 828.2359, found 828.2348.
Anal. Calcd for C54H36O9‚(CHCl3)0.83: C, 70.97; H, 4.00; Cl, 9.51.
Found: C, 70.58; H, 3.72, Cl, 8.57. C-10: 1H NMR (300 MHz,
CDCl3, 25 °C): δ 6.95. 13C{1H} NMR (75.5 MHz, CDCl3, 25
°C): δ 153.1 and 119.8. HR MS (FAB+) m/z calcd for C60H40O10
920.2622, found 920.2587. Anal. Calcd for C60H40O10‚(CHCl3)0.3
:
C, 75.70; H, 4.25. Found: C, 75.41; H, 4.66.
Supporting Information Available: Crystal structure determi-
nation, thermogravimetric analysis, and differential scanning cal-
orimetry of macrocycles and crystallographic data for C-6, C-7,
C-8, and C-9 (CIF). This material is available free of charge via
the Internet at http://pubs.acs.org.
JO0609982
J. Org. Chem, Vol. 71, No. 22, 2006 8617