Novel receptors with quinoline and amide moieties for the biologically important ions

Article abstract of DOI:10.1016/j.tetlet.2010.10.058

New chromogenic anion receptors 2 and 4 utilizing quinoline and nitrophenyl groups as signaling groups were synthesized. In these receptors, amide and amine groups made strong multiple hydrogen interactions with anions. The receptors 2 and 4 bind anions with a selectivity of F^- > CN ^- > CH₃CO₂- and proved to be an efficient naked-eye detector for the fluoride and cyanide ion.

Full text of DOI:10.1016/j.tetlet.2010.10.058

Tetrahedron Letters 51 (2010) 6658–6662
Contents lists available at ScienceDirect
Tetrahedron Letters
journal homepage: www.elsevier.com/locate/tetlet
Novel receptors with quinoline and amide moieties for the biologically
important ions
Jongmin Kang a, , Seung Pyo Jang b, Young-Hee Kim a, Ju Hoon Lee b, Eun Bi Park a, Hong Gyu Lee b,
⇑
Jin Hoon Kim b, Youngmee Kim c, Sung-Jin Kim c, Cheal Kim b,
⇑
a Department of Chemistry, Institute for Chemical Biology, Sejong University, Seoul 143-747, Republic of Korea
b Department of Fine Chemistry, and Eco-Product and Materials Education Center, Seoul National University of Technology, Seoul 139-743, Republic of Korea
c Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Republic of Korea
a r t i c l e i n f o
a b s t r a c t
Article history:
New chromogenic anion receptors 2 and 4 utilizing quinoline and nitrophenyl groups as signaling groups
Received 27 September 2010
Accepted 12 October 2010
Available online 19 October 2010
were synthesized. In these receptors, amide and amine groups made strong multiple hydrogen interac-
tions with anions. The receptors 2 and 4 bind anions with a selectivity of FÀ > CNÀ > CH3CO2 and proved
À
to be an efficient naked-eye detector for the fluoride and cyanide ion.
Ó 2010 Published by Elsevier Ltd.
Keywords:
Anion receptor
Colorimetric receptor
Hydrogen bond
The design and synthesis of efficient receptors capable of bind-
ing biologically and environmentally important anionic species has
received considerable interest in recent years.1 Most of these sen-
sors contain chromogenic or fluorogenic groups that are covalently
or non-covalently linked to the receptor moiety, thus enabling the
colorimetric and fluorimetric sensing of anions.2
Many chemical sensors follow the approach of the covalent
attachment of signaling subunits and binding sites.3 Hydrogen-
bonding sites as binding sites typically used in chromogenic or
fluorogenic chemsensors are ureas,4 thioureas,5,2b calyx[4]pyr-
roles,6 sapphyrins,7 amines8, and amides.9 Usually a single hydro-
gen bond is weak and multiples of such interactions must be
applied for efficient complexation of anions. Among the binding
units mentioned above, amide and amines are the most biologi-
cally relevant groups. They are inspired by anion binding proteins
that exploit the hydrogen bond donor properties of neutral amide
N–H and amine NH2 groups.4a–e
interactions with the hydrogen atoms of these groups through
hydrogen bonding.
These receptors were found to be an efficient detector for fluoride
and cyanide. The anion recognition via hydrogen-bonding interac-
tions could be easily monitored by anion-complexation induced
changes in UV–vis absorption spectra and with the naked eye.
The receptors 2 and 4 were synthesized by the reaction of both
2- or 4-nitroaniline and 8-aminoquinoline group with a simple
2-bromoacetyl bromide (Schemes 1 and 2).11 The X-ray structure
Previously, we reported on novel colorimetric receptors con-
taining a nitrophenyl group or a benzophenone group as chromo-
genic signaling subunit and urea/thiourea as binding sites, which
were selective for fluoride or acetate ion.10 As an extension of
our efforts, we have designed new simple receptors 2 and 4, which
have both a nitrophenyl group and a quinoline group as chromo-
genic signaling subunits. In these receptors, amide and amine
groups are incorporated so that anions can make strong multiple
⇑
Corresponding authors. Tel.: +82 2 970 6693; fax: +82 2 973 9149 (J.K.); fax:
+82 2 462 9954 (C.K.).
E-mail addresses: kangjm@sejong.ac.kr (J. Kang), chealkim@snut.ac.kr (C. Kim).
Scheme 1. The synthetic procedure for the anion receptor 2.
0040-4039/$ - see front matter Ó 2010 Published by Elsevier Ltd.
doi:10.1016/j.tetlet.2010.10.058

J. Kang et al. / Tetrahedron Letters 51 (2010) 6658–6662
6659
Figure 1. The structure of 2 showing the atom-labeling scheme. Displacement
ellipsoids are shown at the 50% probability level.
of 2 is shown in Figure 1. The crystallographic data, and the
selected bond lengths and angles are given in Tables S1 and S2
(see Supplementary data).
Scheme 2. The synthetic procedure for the anion receptor 4.
The receptors 2 and 4 displayed strong absorption bands at
320 nm and 346 nm in acetonitrile, respectively. Figure 2 shows
the family of spectra obtained over the course of the titration of
solution 2 with tetrabutylammonium fluoride in acetonitrile. As
isosbestic point for both compounds indicates that only two spe-
cies were present at equilibrium over the course of the titration
experiment. From the titration experiments, it was found that both
compounds 2 and 4 were deprotonated by the basic fluoride ion.12
The deprotonation was confirmed through the titration experi-
ments with tetrabutylammonium hydroxide ion (Fig. 2c and d).
Assuming 1:1 stoichiometry, a Benesi–Hildebrand plot13 by use
of absorption intensity change at 320 nm and 346 nm gave equilib-
rium constants for deprotonation. From the experiments, the
fluoride ions were added to the 40 lM solution of 2, kmax of 2
moved from 320 nm to 431 nm and the spectra showed the clear
isosbestic point at 356 nm. In the case of 4 in acetonitrile solution
at the same concentration, the intensity of the peak at 346 nm was
decreased as fluoride ions were added and the spectra showed an
isosbestic point at 369 nm (Fig. 2b). The presence of the sharp
Host
2eq.
4eq.
6eq.
0.35
host
a
b
0.7
1eq.
0.3
0.25
0.2
0.6
0.5
0.4
0.3
0.2
0.1
0
3eq.
8eq.
10eq.
12eq.
14eq.
16eq.
18eq.
20eq.
22eq.
24eq.
27eq.
30eq.
35eq.
40eq.
50eq.
60eq.
70eq.
80eq.
5eq.
7eq.
9eq.
0.15
0.1
11eq.
13eq.
15eq.
17eq.
19eq.
21eq.
23eq.
0.05
0
250
350
450
250
350
450
Host
0.45
0.4
c
d
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
Host
1eq.
1eq.
2eq.
2eq.
3eq.
0.35
0.3
5eq.
3eq.
7eq.
5eq.
10eq.
13eq.
16eq.
20eq.
25eq.
30eq.
40eq.
50eq.
70eq.
100eq.
0.25
0.2
7eq.
10eq.
15eq.
20eq.
25eq.
30eq.
40eq.
0.15
0.1
0.05
0
250
350
450
250
350
450
Figure 2. Family of spectra recorded over the course of titration of 40
lM
acetonitrile solution of the receptors
2
(a) and
4
(b) with the standard solution
tetrabutylammonium fluoride and 2 (c) and 4 (d) with the standard solution tetrabutylammonium hydroxide.

6660
J. Kang et al. / Tetrahedron Letters 51 (2010) 6658–6662
Figure 3. 1H NMR spectra of 2 mM of 2 with increased amounts of tetrabutylammonium fluoride (0–6.5 equiv) in CD3CN.
a
b
host
Host
1eq.
3eq.
5eq.
0.7
0.6
1eq.
2eq.
3eq.
0.6
0.5
0.4
0.3
0.2
0.1
0
0.5
0.4
0.3
0.2
0.1
0
4eq.
5eq.
7eq.
7eq.
10eq.
15eq.
20eq.
30eq.
40eq.
60eq.
80eq.
100eq.
150eq.
200eq.
300eq.
9eq.
11eq.
13eq.
15eq.
17eq.
20eq.
25eq.
30eq.
40eq.
50eq.
70eq.
100eq.
150eq.
250eq.
250
350
450
250
350
450
Figure 4. Family of spectra recorded over the course of titration of 40 lM acetonitrile solution of the receptor 2 with the standard solution tetrabutylammonium cyanide (a)
and tetrabutylammonium aceatate (b).
equilibrium constants of the receptors 2 and 4 for fluoride were
calculated as 1.7 Â 103 and 8.3 Â 102 MÀ1, respectively.
tion phenomenon of amide hydrogen was also observed from the
chemical shift during titration. For example, in the case of
compound 2, the doublet at 7.8 ppm moved slightly downfield
when the fluorides added are less than 1 equiv (Fig. 3), and then
showed large upfield shifts when more than 2 equiv of fluoride
added. However, when tetrabutylammonium hydroxide was added
to the solution of compound 2, the doublet at 7.8 ppm showed only
upfield shifts (data not shown). Therefore, it is likely that the initial
downfield shift arises from H-bonding to the anion, but the subse-
quent upfield shift could be explained by the deprotonation of
amide hydrogen.
This phenomenon could be confirmed by a 1H NMR titration. In
CD3CN, amide N–H hydrogen peaks of receptors 2 and 4 became
invisible upon addition of fluoride ion. However, amine peaks of
the compounds 2 and 4 showed downfield shifts. For example,
the amine peak of the compound 2 which appeared about
6.90 ppm showed a downfield shift until 7.18 ppm, indicating that
both amide and amine participate in the binding event (Fig. 3).
These results suggest that both compounds 2 and 4 interact with
fluoride through hydrogen bonds. Another evidence of deprotona-

J. Kang et al. / Tetrahedron Letters 51 (2010) 6658–6662
6661
shielding effect and promotes an upfield shift and (ii) A through-
space effect, which causes deshielding and promotes a downfield
shift. In this case, through-bond propagation dominates, and an
upfield shift is observed.
1.8
1.6
1.4
1.2
1
Analysis of chemical shift utilizing EQNMR14 gave equilibrium
constants 1.6 Â 103 and 5.0 Â 102 MÀ1 for the receptors 2 and 4,
respectively, which are similar values obtained from UV–vis
titration.
Chloride
With cyanide, a similar phenomenon was observed. In UV–vis
titration with cyanide, kmax of 2 was moved from 320 nm to
431 nm and spectra showed the clear isosbestic point at 356 nm
again (Fig. 4). From the experiments, the equilibrium constants
for cyanide were calculated as 1.6 Â 103 and 2.8 Â 102 MÀ1 for
the receptors 2 and 4, respectively. Fluoride and cyanide showed
similar deprotonation equilibrium constants for the receptors 2
and 4.
0.8
0.6
0.4
0.2
0
Dihydrogen
phosphate
acetate
0
0.2
0.4
0.6
0.8
1
However, titration spectra of acetate were somewhat different
with those of fluoride and cyanide. For example, as acetate ions
[H]/{[H]+[G]}
were added to the 40 lM solution of 2, the spectra shifted slightly
Figure 5. Job plots of the receptor 2 and various anions.
to longer wavelength and showed a new isosbestic point at 326 nm
(Fig. 4b). Spectra with the new isosbestic point at 326 nm without
a kmax at 431 nm suggest that hydrogen bonding is a predominant
interaction in the case of acetate at the concentration we
investigated.
Table 1
The association constants (MÀ1) of the receptors 2 and 4 with various anions in
acetonitrile
We also investigated association constants of other anions.
Their binding stoichiometry was determined with the Job plot
and 1: 1 binding was confirmed (Fig. 5). The results are summa-
rized in Table 1. The receptors 2 and 4 interact with most of anions
through hydrogen bonding at the concentration we investigated
except fluoride and cyanide. In addition, the receptor 2 showed
higher affinities than the receptor 4 for the all the anions investi-
gated. These results could be explained by two possibilities: (1)
one is that the inductive effect of 4-nitro group is stronger than
that of 2-nitro group in the benzene ring and (2) the other is that
2-nitro group has an intra-molecular H-bonding to the hydrogen
atom of the amide group, thus inhibiting the hydrogen bonding
with anions.
Anion
2
4
UV (Ka)
NMR (Ka)
1.6 Â 103
UV (Ka)
NMR (Ka)
5.0 Â 102
FÀ
1.7 Â 103
8.8 Â 102
1.6 Â 103
4.1 Â 102
4.6 Â 102
8.4 Â 10
4.1 Â 10
3.5 Â 10
1.1 Â 10
8.3 Â 102
1.5 Â 102
2.8 Â 102
9.6 Â 10
1.4 Â 10
—
—
9
—
À
CH3CO2
CNÀ
À
C6H5CO2
À
H2PO4
ClÀ
BrÀ
IÀ
À
HSO4
For titration, CH2 peak next to amide group or amine peak was
used. For example, in the case of receptor 2, CH2 peak next to
amide appeared at 4.17 ppm. This signal moved from 4.17 ppm
to 3.89 ppm until 6.5 equivalents of fluoride ion were present
and no more shifts were observed. In fact, two effects are expected
as a result of hydrogen bond formation between the receptor sub-
unit and the anion; (i) A through-bond propagation, which causes a
Figure 6 shows the color change of the solutions of the receptors
2 and 4 upon additions of various anions in DMSO. It can be seen
that the color changes from colorless to yellow in the presence of
fluoride and cyanide with naked eye. As expected, the color change
was more distinct in the receptor 2. However, the receptor 4
showed more selective color change than the receptor 2. Other an-
ions did not induce any color changes even with excess amounts.
Figure 6. The color changes of the receptors 2 (a) and 4 (b) when 100
lM acetonitrile solutions of receptors were treated with 5 equiv of various anions.

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J. Kang et al. / Tetrahedron Letters 51 (2010) 6658–6662
5155; (e) Ayling, A. J.; Perez-Payan, M. N.; Davis, A. P. J. Am. Chem. Soc. 2001,
In summary, we developed new chromogenic anion receptors 2
123, 12716.
and 4 utilizing quinoline and nitrophenyl group as the signaling
group. The receptors 2 and 4 bind anions via hydrogen bonds with
5. (a) Gunnlaugsson, T.; Davis, A. P.; O’Brien, J. E.; Glynn, M. Org. Biomol. Chem.
2005, 3, 48; (b) Kim, S. K.; Singh, N. J.; Kim, S. J.; Swamy, K. M. K.; Kim, S. H.; Lee,
K. H.; Kim, K. S.; Yoon, J. Tetrahedron 2005, 61, 4545; (c) Bühlmann, P.;
Nishizawa, S.; Xiao, K. P.; Umezawa, Y. Tetrahedron 1997, 53, 1647; (d) Benito, J.
M.; Gómez-García, M.; Blanco, J. L. J.; Mellet, C. O.; Fernández, J. M. G. J. Org.
Chem. 2001, 66, 1366; (e) Dryfe, R. A. W.; Hill, S. S.; Davis, A. P.; Joos, J.-B.;
Roberts, E. P. L. Org. Biomol. Chem. 2004, 2, 2716; (f) Fan, E.; Van Arman, S. A.;
Kincaid, S.; Hamilton, A. D. J. Am. Chem. Soc. 1993, 115, 369.
a selectivity of FÀ > CNÀ > CH3CO2 and proved to be an efficient
À
naked-eye detector for the fluoride and cyanide ion.
Acknowledgments
6. Panda, P. K.; Lee, C.-H. J. Org. Chem. 2005, 70, 3148.
7. Sessler, J. L.; Davis, J. M. Acc. Chem. Res. 2001, 34, 989.
Financial support from Korea Ministry Environment ‘ET-Human
resource development Project’ and the Korean Science & Engineer-
ing Foundation (R01-2008-000-20704-0 and 2009-0074066) is
gratefully acknowledged.
This research was supported by Basic Science Research Program
through the National Research Foundation of Korea (NRF) funded
by the Ministry of Education, Science and Technology (2010-
0021333).
8. Wichmann, K.; Antonioli, B.; Söhnel, T.; Wenzel, M.; Gloe, K.; Gloe, K.; Price, J.
R.; Lindoy, L. F.; Blake, A. J.; Schröder, M. Coord. Chem. Rev. 2006, 250, 2987.
9. (a) Chmielewski, M. J.; Jurczak, J. Chem. Eur. J. 2005, 11, 6080; (b) Bao, X.; Zhou,
Y. Sens. Actuators, B 2010, 147, 434; (c) Kang, S. O.; Linares, J. M.; Powell, D.;
VanderVelde, D.; Bowman-James, K. J. Am. Chem. Soc. 2003, 125, 10152; (d)
Kondo, S.-i.; Hiraoka, Y.; Kurumatani, N.; Yano, Y. Chem. Commun. 2005, 1720;
(e) Xie, H.; Yi, S.; Wu, S. J. Chem. Soc., Perkin Trans. 2 1999, 2751; (f) Sessler, J. L.;
An, D.; Cho, W.-S.; Lynch, V.; Marquez, M. Chem. Eur. J. 2005, 11, 2001; (g)
Chellappan, K.; Singh, N. J.; Hwang, I.-C.; Lee, J. W.; Kim, K. S. Angew. Chem., Int.
Ed. 2005, 44, 2899; (h) Nishiyabu, R.; Anzenbacher, P., Jr. J. Am. Chem. Soc. 2005,
127, 8270.
Supplementary data
10. (a) Kim, Y.-J.; Kwak, H.; Lee, S. J.; Lee, J. S.; Kwon, H. J.; Nam, S. H.; Lee, K.; Kim,
C. Tetrahedron 2006, 62, 9635; (b) Kang, J.; Lee, Y. J.; Lee, S. K.; Lee, J. H.; Park, J.
J.; Kim, Y.; Kim, S.-J.; Kim, C. Supramol. Chem. 2010, 22, 267.
Supplementary data (X-ray crystallography, crystal data, and
structure refinement for 2, bond lengths [Å] and angles [°] for 2,
and crystal structure of intermolecular H-bonds between the mol-
ecule 2 and water molecules) associated with this article can be
found, in the online version, at doi:10.1016/j.tetlet.2010.10.058.
11. Synthesis of compound 1: 1 was immediately precipitated when 4-nitroaniline
(1.67 g, 12.0 mmol) and 2-bromoacetyl bromide (0.89 mL, 10.0 mmol) were
mixed together in chloroform (200 mL) at room temperature under nitrogen.
The mixture was evaporated to produce crude residue, which was purified by
chromatography (silica gel, methylene chloride). Yield 51.1%. Anal. Calcd for
C8H7BrN2O3 (259.06): C, 37.09; H, 2.72; N, 10.81. Found: C, 37.23; H, 2.85; N,
10.73. 1H NMR (DMSO-d6): 10.99 (s, 1H), 8.23 (d, 2H), 7.84 (d, 2H), 4.10 (s, 2H).
IR (KBr): 3276 (N–H), 1684 (C@O), 1506 (NO2) cmÀ1. FAB MS m/z (M+): calcd,
259.06, found, 259.27.
References and notes
Synthesis of compound 2: To
a mixture of 1 (1.30 g, 5.0 mmol) and 8-
aminoquinoline (0.88 mL, 6.0 mmol) in acetonitrile (130 mL) was added N,N-
diisopropylethylamine (0.54 mL, 6.0 mmol). The resulting solution was
refluxed for 12 h and concentrated. The pure product was recrystallized in
acetonitrile. Yield 33.7%. Anal. Calcd for C17H14N4O3 (322.32): C, 63.35; H, 4.38;
N, 17.38; O, 14.89. Found: C, 63.54; H, 4.37; N, 17.08. 1H NMR (DMSO-d6):
10.90 (s, 1H), 8.80 (d, 1H), 8.25 (m, 3H), 7.89 (d, 2H), 7.55 (t, 1H), 7.39 (t, 1H),
7.15 (d, 1H), 7.02 (t, 1H), 6.61 (d, 1H), 4.23 (s, 2H). IR (KBr): 3352 (N–H), 1715
1. (a) Gavette, J. V.; McGrath, J. M.; Spuches, A. M.; Sargent, A. L.; Allen, W. E. J. Org.
Chem. 2009, 74, 3706–3710; (b) Bhosale, S. V.; Kalyankar, M. B.; Langford, S. J.
Org. Lett. 2009, 11, 5418–5421; (c) Lin, Y.-C.; Chen, C.-T. Org. Lett. 2009, 11,
4858–4861; (d) Melaimi, M.; Gabbai, F. P. J. Am. Chem. Soc. 2005, 127, 9680; (e)
Martinez-Manez, R.; Sancenon, F. Chem. Rev. 2003, 103, 4419; (f) Bondy, C. R.;
Loeb, S. J. Coord. Chem. Rev. 2003, 240, 77; (g) Gale, P. A. Coord. Chem. Rev. 2001,
213, 79; (h) Thiagarajan, V.; Ramamurthy, P.; Thirumalai, D.; Ramakrishnan, V.
T. Org. Lett. 2005, 7, 657; (i) Burns, D. H.; Calderon-Kawasaki, K.; Kularatne, S. J.
Org. Chem. 2005, 70, 2803; (j) Yoon, J.; Kim, S. K.; Singh, N. J.; Kim, K. S. Chem.
Soc. Rev. 2006, 35, 355; (k) Cametti, M.; Rissanen, K. Chem. Commun. 2009,
2809–2829; (l) Miyaji, H.; Sessler, J. L. Angew. Chem., Int. Ed. 2001, 40, 154–157.
2. (a) Sansone, F.; Chierici, E.; Casnati, A.; Ungaro, R. Org. Biomol. Chem. 2003, 1,
1802; (b) Gunnlaugsson, T.; Davis, A. P.; Hussey, G. M.; Tierney, J.; Glynn, M.
Org. Biomol. Chem. 2004, 2, 1856; (c) Lee, J. Y.; Cho, E. J.; Mukamel, S.; Nam, K. C.
J. Org. Chem. 2004, 69, 943; (d) Cho, E. J.; Moon, J. W.; Ko, S. W.; Lee, J. Y.; Kim, S.
K.; Yoon, J.; Nam, K. C. J. Am. Chem. Soc. 2003, 125, 12376; (e) Singh, N. J.; Kim, S.
J.; Swamy, K. M. K.; Kim, S. H.; Lee, K.-H.; Kim, K. S.; Yoon, J. Tetrahedron 2005,
61, 4545; (f) Jose, D. A.; Kumar, D. K.; Ganguly, B.; Das, A. Org. Lett. 2004, 6,
3445; (g) Tozawa, T.; Misawa, Y.; Tokita, S.; Kubo, Y. Tetrahedron Lett. 2000, 41,
5219; (h) Kato, R.; Nishizawa, S.; Hayashita, T.; Teramae, N. Tetrahedron Lett.
2001, 42, 5053; (i) Gunnlaugsson, T.; Davis, A. P.; Glynn, M. Chem. Commun.
2001, 2556; (j) Sasaki, S.; Citterio, D.; Ozawa, S.; Suzuki, K. J. Chem. Soc., Perkin
Trans. 2 2001, 2309; (k) Lee, D. H.; Lee, H. Y.; Lee, K. H.; Hong, J.-I. Chem.
Commun. 2001, 1188; (l) Hennrich, G.; Sonnenschein, H.; Resch-Genger, U.
Tetrahedron Lett. 2001, 42, 2805; (m) Jiménez, D.; Martínez-Máñez, R.;
Sancenón, F.; Soto, J. Tetrahedron Lett. 2002, 43, 2823; (n) Lee, D. H.; Lee, H.
Y.; Hong, J.-I. Tetrahedron Lett. 2002, 43, 7273; (o) Gunnlaugsson, T.; Kruger, P.
E.; Lee, T. C.; Parkesh, R.; Pfeffer, F. M.; Hussey, G. M. Tetrahedron Lett. 2003, 44,
6575.
(C@O), 1520 (NO2) cmÀ1 13C NMR (DMSO-d6, 300 MHz): d 170.67, 148.01,
.
144.64, 140.51, 138.35, 136.69, 135.54, 132.72, 128.89, 128.28, 125.98, 125.35,
124.36, 122.57, 115.53, 105.84, 48.42. FAB MS m/z (M+): calcd, 322.32, found,
322.28.
Synthesis of compound 3: A mixture of 2-bromoacethyl bromide (0.89 mL,
10.0 mmol) and 2-nitroaniline (1.13 g, 8.0 mmol) in acetonitrile (60 mL) was
refluxed for 6 h. After cooling, the mixture was evaporated to produce crude
residue, which was recrystallized from methanol/water, filtered, and dried.
Yield 52.7%. Anal. Calcd for C8H7BrN2O3 (259.06): C, 37.09; H, 2.72; N, 10.81.
Found: C, 37.11; H, 2.65; N, 10.85. 1H NMR (DMSO-d6): 10.71 (s, 1H), 8.00 (d,
1H), 7.74 (m, 2H), 7.42 (t, 1H), 4,13 (s, 2H). IR (KBr): 3341 (N–H), 1686 (C@O),
1505 (NO2) cmÀ1
125.73 (2C), 119.71 (2C), 30.84. FAB MS m/z (M+): calcd, 259.06, found, 259.23.
Synthesis of compound 4: To mixture of (1.04 g, 4.0 mmol) and 8-
.
13C NMR (DMSO-d6, 300 MHz): d 166.45, 145.36, 143.32,
a
3
aminoquinoline (1.03 g, 7.0 mmol) in tetrahydrofuran (40 mL) was added
N,N-diisopropylethylamine (0.63 mL, 7.0 mmol). The resulting solution was
refluxed for 12 h. The mixture was evaporated to produce crude residue, which
was purified by chromatography (silica gel, methylene chloride/0–4%
tetrahydrofuran), filtered, and dried. Yield 73.7%. Anal. Calcd for C17H14N4O3
(322.32): C, 63.35; H, 4.38; N, 17.38; O, 14.89. Found: C, 63.33; H, 4.45; N,
17.42. 1H NMR (DMSO-d6): 10.83 (s, 1H), 8.83 (d, 1H), 8.28 (d, 1H), 8.15 (d, 1H),
8.03 (d, 1H), 7.75 (t, 1H), 7.56 (t, 1H), 7.38 (m, 2H), 7.23 (t, 1H), 7.19 (d, 1H),
6.63 (d, 1H), 4.16 (s, 2H). IR (KBr): 3435 (N–H), 1708 (C@O), 1501 (NO2) cmÀ1
13C NMR (DMSO-d6, 300 MHz):
170.43, 147.89, 145.66, 144.66, 142.94,
.
3. (a) Kwon, J. Y.; Jang, Y. J.; Kim, S. K.; Lee, K.-H.; Kim, J. S.; Yoon, J. J. Org. Chem.
2004, 69, 5155; (b) Kim, S. K.; Singh, N. J.; Kim, S. J.; Kim, H. G.; Kim, J. K.; Lee, J.
W.; Kim, K. S.; Yoon, J. Org. Lett. 2003, 5, 2083.
4. (a) Boiocchi, M.; Boca, L. D.; Gomez, D. E.; Fabbrizzi, L.; Licchelli, M.; Monzani, E.
J. Am. Chem. Soc. 2004, 126, 16507; (b) Werner, F.; Schneider, H.-J. Helv. Chim.
Acta 2000, 83, 465; (c) Snellink-Ruel, B. H. M.; Antonisse, M. M. G.; Engbersen, J.
F. J.; Timmerman, P.; Reinhoudt, D. N. Eur. J. Org. Chem. 2000, 165; (d) Kwon, J.
Y.; Jang, Y. J.; Kim, S. K.; Lee, K. H.; Kim, J. S.; Yoon, J. Y. J. Org. Chem. 2004, 69,
d
138.22, 136.66, 128.93, 128.36, 125.72 (2C), 122.53, 119.58 (2C), 114.86,
105.45, 47.63. FAB MS m/z (M+): calcd, 322.32, found, 322.50.
12. Amendola, V.; Esteban-Gomez, D.; Fabbrizzi, L.; Licchelli, M. Acc. Chem. Res.
2006, 39, 343.
13. Benesi, H.; Hildebrand, H. J. Am. Chem. Soc. 1949, 71, 2703.
14. Hynes, M. J. J.Chem. Soc., Dalton Trans. 1993, 311.