New N2O2- and N2O3-macrocycle ligands incorporating p-xylyl groups

Article abstract of DOI:10.1081/SCC-200032404

The synthesis and characterization of four dibenzo-substituted macrocycles incorporating mixed nitrogen and oxygen heteroatoms as well as one or two xylyl groups are reported. The X-ray structure of one product containing two xylyl functions is presented.

Full text of DOI:10.1081/SCC-200032404

This article was downloaded by: [University of Illinois Chicago]
On: 18 August 2013, At: 22:15
Publisher: Taylor & Francis
Informa Ltd Registered in England and Wales Registered Number: 1072954
Registered office: Mortimer House, 37-41 Mortimer Street, London W1T
3JH, UK
Synthetic Communications:
An International Journal
for Rapid Communication of
Synthetic Organic Chemistry
Publication details, including instructions for
authors and subscription information:
http://www.tandfonline.com/loi/lsyc20
New N2O2‐ and
N2O3‐Macrocycle Ligands
Incorporating p‐Xylyl Groups
Jeong Kim a , Leonard F. Lindoy b , Tae‐Ho Ahn a &
Gyu‐Sung Choi c
a Department of Chemistry, Seonam University,
Namwon, 590‐711, Korea
b School of Chemistry, University of Sydney,
N.S.W., 2006, Australia
c Department of Chemistry, Gyungnam University,
Masan, 631‐701, Korea
Published online: 19 Apr 2010.
To cite this article: Jeong Kim , Leonard F. Lindoy , TaeHo Ahn & GyuSung Choi
(2004) New N2O2‐ and N2O3‐Macrocycle Ligands Incorporating p‐Xylyl Groups,
Synthetic Communications: An International Journal for Rapid Communication of
Synthetic Organic Chemistry, 34:20, 3653-3659, DOI: 10.1081/SCC-200032404
To link to this article: http://dx.doi.org/10.1081/SCC-200032404
PLEASE SCROLL DOWN FOR ARTICLE
Taylor & Francis makes every effort to ensure the accuracy of all
the information (the “Content”) contained in the publications on our
platform. However, Taylor & Francis, our agents, and our licensors
make no representations or warranties whatsoever as to the accuracy,

completeness, or suitability for any purpose of the Content. Any opinions
and views expressed in this publication are the opinions and views of
the authors, and are not the views of or endorsed by Taylor & Francis.
The accuracy of the Content should not be relied upon and should be
independently verified with primary sources of information. Taylor and
Francis shall not be liable for any losses, actions, claims, proceedings,
demands, costs, expenses, damages, and other liabilities whatsoever
or howsoever caused arising directly or indirectly in connection with, in
relation to or arising out of the use of the Content.
This article may be used for research, teaching, and private study
purposes. Any substantial or systematic reproduction, redistribution,
reselling, loan, sub-licensing, systematic supply, or distribution in any form
to anyone is expressly forbidden. Terms & Conditions of access and use
can be found at http://www.tandfonline.com/page/terms-and-conditions

SYNTHETIC COMMUNICATIONSw
Vol. 34, No. 20, pp. 3653–3659, 2004
New N2O2- and N2O3-Macrocycle Ligands
Incorporating p-Xylyl Groups
1
Jeong Kim,1 Leonard F. Lindoy,2, Tae-Ho Ahn,
*
and Gyu-Sung Choi3
1Department of Chemistry, Seonam University, Namwon 590-711, Korea
2School of Chemistry, University of Sydney, N.S.W., 2006, Australia
3Department of Chemistry, Gyungnam University, Masan 631-701, Korea
ABSTRACT
The synthesis and characterization of four dibenzo-substituted macro-
cycles incorporating mixed nitrogen and oxygen heteroatoms as well as
one or two xylyl groups are reported. The X-ray structure of one
product containing two xylyl functions is presented.
Key Words: Macrocycle; Synthesis; X-ray structure.
In past studies, we investigated the interaction of mixed donor macro-
cyclic ligands incorporating oxygen/nitrogen donor sites with a range of
*
Correspondence: Leonard F. Lindoy, School of Chemistry, University of Sydney,
N.S.W. 2006, Australia; Fax: þ61 2 9351 7067; E-mail: lindoy@chem.usyd.edu.au.
3653
DOI: 10.1081/SCC-200032404
0039-7911 (Print); 1532-2432 (Online)
www.dekker.com
Copyright # 2004 by Marcel Dekker, Inc.

3654
Kim et al.
first-row transition and post transition metal ions.[1–3] We now report the syn-
thesis and characterization of a new series of related macrocyclic ligands 1
through 4, in which one or two xylyl groups have been incorporated in their
ring structures. These semiflexible ring systems, incorporating both p-aryl
and hydrogen-bond acceptor sites (or donor sites in the respective protonated
forms) constitute a class of “hybrid” macrocycles of potential application as
receptors for small molecules and ions.
Condensation of the respective dialdehydes 5 through 8 and a,a0-
diamino-p-xylene in methanol yielded the corresponding cyclic Schiff base
products; these were not isolated but were reduced in situ by step-wise
addition of sodium borohydride to the reaction solution. All reactions
proceeded smoothly. The respective ring-closing reactions were not carried
out under high dilution conditions. Thin layer chromatography on silica gel
[employing triethylamine/ethyl acetate (1:3) as eluent] of the crude products
coupled with their low-resolution mass spectra indicated that small yields of
the corresponding 2:2 condensation products were also formed under the
conditions employed. These 2:2 by-products exhibit little solubility in warm
acetonitrile, while the monomeric products are more soluble (and are
readily crystallized from this solvent), thus providing a means for the purifi-
1
cation of the latter. The high-resolution mass spectra (HRMS) and H- and
13C-NMR spectra of the respective products in each case are consistent with
the assigned structures, with there being no evidence for the presence of
imine groups.
The X-ray structure of 1, crystallized from acetonitrile, is shown in Fig. 1.
The bond lengths and angles are unremarkable. The dihedral angles between
each xylyl aromatic plane and the least squares plane defined by O(1), O(8),
Figure 1. X-ray structure of 1. Thermal ellipsoids are scaled to 30% probability.

New N2O2 and N2O3-Macrocycle Ligands
3655
N(12), and N(19) are c. 858 for the aryl ring in the -NHCH2C2H4CH2NH-
string (namely, close to perpendicular to the O2N2 least squares plane), and c.
298 for the aryl group in the -OCH2C2H4CH2O- string. Overall, while there
appears to be little preorganization of the xylyl groups for p-interaction with
an included guest, this is likely to be little impediment to such binding given
that inspection of CPK (Corey-Pauling-Koltun) models indicates that free
rotation is possible around each of the xylyl methylene groups in this structure.
EXPERIMENTAL
1H- and 13C-NMR spectra were recorded in (D)chloroform on a Bruker
AC-300 spectrometer at 300 and 75 MHz, respectively. High-resolution
mass spectra were obtained on a Jeol JMS HX-100 mass spectrometer.
Melting points are uncorrected. All solid products were dried over phosphorus
pentoxide in a vacuum.
Macrocycle Synthesis
Dialdehyde 5 (Fig. 2)
This was prepared (in higher yield) by a modified procedure to that
reported previously.[4] Salicylaldehyde (2.44 g, 0.02 mol) and a,a0-dibromo-
p-xylene (2.64 g, 0.01 mol) were dissolved in acetonitrile, and potassium
carbonate (5.5 g, 0.04 mol) was added. The mixture was heated at the reflux
for 2 h then filtered. The solution was cooled to room temperature, and the
precipitate that formed was filtered off and washed with 10% aqueous sodium
hydroxide solution (3 ꢀ 100 mL) and recrystallized from acetonitrile to yield
colorless crystals (2.41 g, 84%). M.p. 192–1948C (lit. 1918C).[6] The 1H-
NMR was identical to that reported previously;[6] 13C-NMR d 190.30, 156.47,
137.92, 136.10, 130.21, 129.15, 128.54, 127.21, 120.55, 110.50, 69.85.
Dialdehydes 6 through 8 (Fig. 2)
These were prepared and characterized as described previously.[5,7]
Macrocycle 1 (Fig. 2)
Dialdehyde 5 (3.46 g, 0.01 mol) was dissolved in dry methanol (100 mL),
and aa0-diamino-p-xylene (1.36 g, 0.01 mol) dissolved in methanol (50 mL)
was added dropwise. The mixture was refluxed for 2 h then filtered. Sodium

3656
Kim et al.
Figure 2.
borohydride (1.9 g, 0.05 mol) was added to this solution in small portions at
room temperature. The solvent was removed on a rotary evaporator, and the
residue was dissolved in dichroromethane (100 mL), which was shaken with
water (3 ꢀ 100 mL). The organic phase was separated and dried over
anhydrous sodium sulfate. The solvent was again removed using a rotary
evaporator, and the product that remained was recrystallized from acetonitrile
to yield colorless crystals (1.58 g, 35%). M.p. 135–1368C [Found: m/z
450.2308 (EI), C30H30N2O2 requires M, 450.2307]; dH6.94–7.40 (m, 16H,
aromatic H), 5.05 (s, 4H, ArOCH2), 3.82 (s, 4H, NCH2ArCH2N), 3.76

New N2O2 and N2O3-Macrocycle Ligands
3657
(s, 4H, ArCH2NCH2Ar), 1.91 (s, 2H, NH); dC 156.86, 138.31, 136.32, 130.69,
128.41, 128.22, 127.35, 120.75, 110.82, 69.40, 52.86, 49.20.
Macrocycle 2 (Fig. 2)
In a similar manner to that described above, dialdehyde 6 (2.70 g,
0.01 mol) and a,a0-diamino-p-xylene (1.36 g, 0.01 mol) yielded the product
as colorless crystals after recrystallization from ethanol (1.42 g, 38%).
M.p. 142–1438C; [Found: m/z 374.1996 (EI), C24H26N2O2 requires M,
374.1994]; dH 6.71–7.39 (m, 12H, aromatic H), 4.17 (s, 4H, ArOCH2),
3.87 (s, 4H, NCH2ArCH2N), 3.44 (s, 4H, ArCH2NCH2Ar), 1.81 (s, 2H,
NH); dC 156.64, 136.23, 131.73, 131.04, 127.71, 126.89, 121.74, 113.10,
68.19, 65.23, 61.06.
Macrocycle 3 (Fig. 2)
In a similar manner to that described above, dialdehyde 8 (2.84 g,
0.01 mol) and a,a0-diamino-p-xylene (1.36 g, 0.01 mol) yielded the product
as colorless crystals after recrystallization from ethanol (0.97 g, 25%).
M.p. 113–1148C; [Found: m/z, 388.2150 (EI), C25H28N2O2 requires M,
388.2151]; aH 6.75–7.24 (m, 12H, aromatic H), 4.02 (s, 4H, ArOCH2),
3.72 (s, 4H, NCH2ArCH2N), 3.63 (s, 4H, ArCH2NCH2Ar), 2.15 (quintet,
2H, OCH2CH2CH2O), 1.76 (s, 2H, NH); dC 156.72, 138.92, 130.12, 128.47,
128.21, 128.02, 120.59, 111.18, 64.57, 52.79, 48.65, 29.34.
Macrocycle 4 (Fig. 2)
In a similar manner to that described above, dialdehyde 7 (3.12 g,
0.01 mol) and a,a0-diamino-p-xylene (1.36 g, 0.01 mol) yielded the product
as colorless crystals after recrystallization from ethanol (1.67 g, 40%).
M.p. 130–1328C; [Found: m/z, 418.2257 (EI), C26H30N2O3 requires M,
418.2256]; dH 6.77–7.31 (m, 12H, aromatic H), 3.98 (t, 4H, ArOCH2),
3.78 (s, 4H, NCH2ArCH2N), 3.70 (s, 4H, ArCH2NCH2Ar), 3.66 (t, 4H,
ArOCH2CH2), 1.99 (s, 2H, NH); dC 156.92, 138.96, 130.48, 128.84,
128.42, 128.28, 121.02, 111.85, 70.10, 67.91, 52.90, 47.97.
X-ray Structure of Macrocycle 1
Data were collected at 295(2) K using a Bruker P4 diffractometer employ-
ing graphite-monochromated Mo-Ka radiation generated from a sealed tube
˚
(0.71073 A). The intensities of three standard reflections did not change

3658
Kim et al.
significantly during the data collection. A multiscan empirical absorption cor-
rection was applied to the data using the program SADABS.[8] The structure
was solved by direct methods using SHELXS-97[9] then refined and extended
with SHELXL-97.[9] The structure is illustrated in Fig. 1, the latter showing
30% probability amplitude displacement envelopes for the nonhydrogen
atoms. All nonhydrogen atoms were refined with anisotropic displacement
parameters, whereas the hydrogen atoms were constrained at estimated
positions.
Crystal data: C30H30N2O2, M ¼ 450.56, triclinic, space group P1 (#2),
˚
˚
˚
a ¼ 9.6540(16) A, b ¼ 10.0092(19) A, c ¼ 13.960(3) A, a ¼ 84.23(2)8,
3
23
˚
b ¼ 72.754(15)8, g ¼ 68.424(17)8, V ¼ 1198.0(4) A , Dc ¼ 1.249 g cm
,
,
Z ¼ 2, crystal size 0.4 ꢀ 0.3 ꢀ 0.2 mm, m(Mo-Ka) 0.078 mm21
T (Empirical)min,max ¼ 0.4551, 0.4762, 2umax ¼ 54.0, hkl range 211 to 11,
211 to 12, 216 to 17, Nind ¼ 4709 (Rmerge ¼ 0.0263), Nobs ¼ 2903
(I . 2s(I)), Nvar ¼ 343, residuals R1(F) ¼ 0.0512, wR2(F2) ¼ 0.1309,
2
23
˚
GoF(all) ¼ 1.018, Drmin,max ¼ 20.155, 0.165 e A
. The refinement
residuals are defined as R1 ¼ SkF0j 2 jFck/SjF0j for F0 . 2s(F0) and
wR2 ¼ fS[w(F02 2 Fc2)2]/S[w(Fc2)2]g1/2, where w ¼ 1/[s2(F20) þ (0.0518P)2 þ
0.1348P], P ¼ (F20 þ 2Fc2)/3. CCDC depostition No. 219088.
ACKNOWLEDGMENTS
Gyu-Sung Choi acknowledges Gyungnam University for financial
support. We also thank the Australian Research Council for its support and
Dr. M. Fainerman-Melnikova for assistance.
REFERENCES
1. Kim, J.; Ahn, T.-H.; Lee, M.; Leong, A.J.; Lindoy, L.F.; Rumbel, B.R.;
Skelton, B.W.; Strixner, T.; Wei, G.; White, A.H. Metal ion recognition.
The interaction of cobalt(II), nickel(II), copper(II), zinc(II), cadmium(II),
silver(I) and lead(I) with N-benzylated macrocycles incorporating O2N2-,
O3N2- and O2N3-donor sets. J. Chem. Soc., Dalton Trans. 2002, 3993
and references therein.
2. Kim, J.-H.; Leong, A.J.; Lindoy, L.F.; Kim, J.; Nachbaur, J.; Nezhadali, A.;
Rounaghi, G.; Wei, G. Metal-ion recognition. Competitive bulk membrane
transport of transition and post transition metal ions using oxygen-nitrogen
donor macrocycles as ionophores. J. Chem. Soc., Dalton Trans. 2000,
3453.

New N2O2 and N2O3-Macrocycle Ligands
3659
3. Lindoy, L.F. Tailoring macrocycles for metal ion binding. Pure and Appl.
Chem. 1997, 69, 2179.
4. Reddy, D.; Chandrashekar, T.K. Short-chain basket handle porphrins:
synthesis and characterizaation. J. Chem. Soc., Dalton Trans. 1992, 619.
5. Grimsley, P.G.; Lindoy, L.F.; Lip, H.C.; Smith, R.J.; Baker, J.T. Synthesis
of new 14-, 15-, and 16-membered crown compounds containing oxygen
and nitrogen heteroatoms. Aust. J. Chem. 1977, 30, 2095.
6. Osuka, A.; Kobayashi, F.; Maruyama, K. Syntheses of strapped, dimeric
and trimeric porphyrins based on intramolecular macrocyclizations. Bull.
Chem. Soc. Japan 1991, 64, 1213.
7. Baldwin, D.S.; Duckworth, P.A.; Erickson, G.R.; Lindoy, L.F.;
McPartlin, M.; Mockler, G.M.; Moody, W.E.; Tasker, P.A. New macrocyc-
lic ligands. Synthesis of an extensive series of potentially pentadentate
ligands containing mixed nitrogen, oxygen and/or sulfur heteroatoms.
The x-ray structure used to examine of an O2N2S-derivative. Aust. J.
Chem. 1987, 40, 1861; Davis, C.A.; Duckworth, P.A.; Lindoy, L.F.;
Moody, W.E. New Macrocyclic ligands. VI. 20- to 22-Membered
dibenzo-substituted rings incorporating mixed, nitrogen, oxygen and or
sulfur/donor atoms. Aust. J. Chem., 1995, 48, 1819.
8. Sheldrick, G.M. SADABS: Empirical absorption and correction software.
¨
University of Gottingen, Institut fur Anorganische Chemie der Universitat,
Tammanstrasse 4, D-3400 Gottingen, Germany, 1999.
¨
¨
¨
¨
9. Sheldrick, G.M. SHELX-97: Programs for crystal structure analysis.
¨
University of Gottingen, Institut fur Anorganische Chemie der
Universitaat, Tammanstrasse 4, D-3400 Gottingen, Germany, 1997.
¨
¨
¨
¨
Received in the UK October 20, 2003