Photochromic behavior of several new synthesized dyes via Zincke salts

Article abstract of DOI:10.1002/poc.1623

Synthesis of several 'dyes', analogs of retinal imine visual pigment via nucleophilic attack of some secondary amines to pyridinium salts following precyclic ring-opening reaction, is discussed. The photochromic properties of these dyes have been studied by UV-Vis spectroscopy under irradiation of UV light. Copyright

Full text of DOI:10.1002/poc.1623

Research Article
Received: 21 June 2009,
Revised: 4 August 2009,
Accepted: 22 August 2009,
Published online in Wiley InterScience: 30 October 2009
(www.interscience.wiley.com) DOI 10.1002/poc.1623
Photochromic behavior of several new
synthesized dyes via Zincke salts
a
a
a
a
*
N. O. Mahmoodi , M. Mamaghani , A. Ghanadzadeh , M. Arvand
and M. Fesangharia
Synthesis of several ‘dyes’, analogs of retinal imine visual pigment via nucleophilic attack of some secondary amines
to pyridinium salts following precyclic ring-opening reaction, is discussed. The photochromic properties of these
dyes have been studied by UV-Vis spectroscopy under irradiation of UV light. Copyright ß 2009 John Wiley & Sons,
Ltd.
Supporting information may be found in the online version of this paper.
Keywords: nucleophilic attack; photochromism; pyridinium salts; retinal imine analogs; Zincke salt
INTRODUCTION
RESULTS AND DISCUSSION
The potential application of photochromic materials as con-
trollable molecular media in photon-based molecular devices
such as memories and switches has turned such materials into an
expanding research field. The most commonly used definition of
photochromism is a reversible color change induced by light
between two species which have absorption in different regions
of the visible spectrum (Scheme 1).
The synthesis used in this study is a practical procedure that
permits us to prepare very beautiful crystalline dyes 2–4 (R1 ¼ H,
phenyl) from Zincke salts (DNP) 2,4-dinitrophenyl 1 and
secondary amines diethylamine or pyrrolidine according to
Scheme 2. Pyridinium salts are a versatile class of compounds
used as phase transfer catalysts,[16] initiators of cationic
polymerization,[17] wide range antimicrobials,[18] enzyme inhibi-
tors,[19,20] acylating agents,[21] dyes, and cationic surfactants.[22]
Their chiral representatives, that is, pyridinium salts containing a
chiral auxiliary group linked to the ring nitrogen, have been
largely used as starting materials in asymmetric synthesis to
obtain substituted chiral dihydropyridines,[23] tetrahydropyri-
dines,[24] piperidines,[25] and nitrogenated complex compounds
such as natural alkaloids[26] and synthetic candidates for drugs.[20]
The N-2,4-dinitrophenyl-pyridinium salts 1a and 1b were
freshly prepared and typically isolated and purified by
recrystallization and characterized. Upon heating a secondary
amine such as diethylamine or pyrrolidine with these salts (1)
leads to the opening of the pyridinium ring and the formation of
dyes 2, 3, and 4 (Scheme 2). Synthesis of N-arylpyridinium salts 5
requires a two-step procedure and is called a Zincke reaction.
Several arylpyridinium salts bearing a nitrone spin trap as
potential mitochondria-targeted antioxidants were recently
reported by Hartley et al.[27] We did not make any effort to
prepare them in the study. A synthesis sequence for the
preparation of 3 and 4 was not previously reported. However, a
similar type of mechanism, as depicted for the preparation of 2,
was established early[28–30] (Scheme 3). The kinetically less stable
The difference in geometry and electronic structure between
the two isomers, which is at the origin of the color switch, has also
been successfully exploited to reversibly control other properties
such as the phase behavior of liquid crystals, refractive index,
fluorescence, redox potential, electron transfer, and nonlinear
optical properties. Although many types of photochromic
compounds have been reported so far, crystals that show
photochromic reactions in the crystal state are very rare.[1,2] The
ring-opening reaction of pyridinium salts dates back to more
than a century to the pioneering work of Zincke and Konig.[3–6] In
this study we report the activation of pyridine from pyridinium
salt 1 (Scheme 2), followed by treatment with primary amines,
leading to the formation of a new unsaturated aldehyde 4, while
the use of secondary amines such as diethylamine gives 3 and
pyrrolidine affords 2, and provides the products of ring opening.
Recently we became interested in the photochromism and
photoproduction of 1,3-diazabicyclo[3.1.0]hex-3-ene derivatives
with various substitutions.[7–13] We used novel potentiometers as
membrane sensors based on 6-(4-nitrophenyl)-2,4-diphenyl-3,5-
diazabicyclo[3.1.0] hex-2-ene and 6-(4-nitrophenyl)-2-phenyl-4,4-
dipropyl-3,5-diazabicyclo[3,1,0] hex-2-ene for detecting Sn (II)[14]
and strontium (II) ions[15] at trace levels in real samples,
respectively.
*
Correspondence to: N. O. Mahmoodi, Department of Chemistry, University of
Guilan, PO Box 1914, Rasht, Iran.
E-mail: mahmoodi@guilan.ac.ir
Solid-state organic photochromic molecules have attracted
much attention due to their potential applications in various
optoelectronic devices such as optical memory, optical switch,
electronic display, information storage, and so on.
a
N. O. Mahmoodi, M. Mamaghani, A. Ghanadzadeh, M. Arvand, M. Fesanghari
Department of Chemistry, University of Guilan, Rasht, Iran
J. Phys. Org. Chem. 2010, 23 266–270
Copyright ß 2009 John Wiley & Sons, Ltd.

PHOTOCHROMIC BEHAVIOR OF NEWLY SYNTHESIZED DYES
Scheme 1.
Scheme 3.
Photochromic conversion of 2E leads to the formation of
enamine red isomer 2E(. Subsequent hydrolyzation of 2E( in the
presence of base hydrolyzed to aldehyde 7 and leads to the
formation of aldehyde 4 (Scheme 4).
Resonance structures for the preparation of 4 illustrate how the
lone pair of electrons on the pyrrolidine nitrogen of the yellow
and red 2E is in resonance contact with the two nitro groups. A
very similar transfer of charge between these groups takes place
when the molecule absorbs light. The electric field of the light
pushes the electrons of the 2E (yellow) along the polyene chain
away from the pyrrolidine ring and toward the dinitro 2E’ (red).
This cycle can be repeated several times.
Scheme 2.
As indicated in Scheme 1, 2Z molecule is relatively similar in
shape to the cis-retinal imine that functions in the visual pigment
of eye. The UV-Vis absorption spectra of 2a, 2b, 3a, 3b were
recorded in seven solvents at a concentration of 10ꢀ4–10ꢀ6 M in
the wavelength range of 300–700 nm. Samples were irradiated
with 254 nm UV-wave lamp after 5, 10, 20, 60, and 90 min. The
spectra for each samples repeated three times with 2 min interval
for each sample (1 ꢁ 10ꢀ5) in various organic solvents with
different polarities were recorded. Solvents were selected on the
Z-isomer 2Z upon absorption of light rapidly isomerizes to the
more stable thermodynamic E-isomer 2E together with the
generation of an electrical pulse corresponding to a large cage in
the molecular dipole moment upon photoexcitation.
Formation of aldehyde 4 involves a different mechanism
wherein the pyridine ring of 6a proceeds through ring opening
by sigmatropic rearrangement to yellow isomer 2E (Scheme 3).
Scheme 4.
J. Phys. Org. Chem. 2010, 23 266–270
Copyright ß 2009 John Wiley & Sons, Ltd.
www.interscience.wiley.com/journal/poc

N. O. MAHMOODI ET AL.
Table 1. Solvatochromic data lmax (nm) for 2a, 2b, 3a, 3b in seven solvents with P* values by Kamlet et al.[33]
Irradiation
UV lamp
(254 nm)
Irradiation
UV lamp
(254 nm)
Irradiation
UV lamp
(254 nm)
Irradiation
UV lamp
(254 nm)
*
Solvent
EtOAc
p
2a
2b
3a
3b
0.45 480, 419, 360
1,4-Dioxane 0.49 472, 420, 350
a
b
c
d
d
e
f
490, 422, 374
481, 422, 370
470 w, 425
508, 422, 377
512, 427, 376
508, 433, 378
535, 428, 392
g
h
d
i
k
l
482, 358
470, 356
452, 350
501, 366
505, 362
504, 365
470, 350
I
d
d
I
d
n
m
493, 361
483, 360
470, 355
517, 370
515, 362
505, 368
462, 345
i
d
d
I
d
o
p
MeOH
Acetone
CH3CN
CH2Cl2
DMSO
0.60
0.62
0.66
455, 423
497, 421
502, 419
0.73 508, 425, 372
1.00 541, 422, 376
m
a, with time lapse, after 10 min, lmax 480 nm disappeared, and the color changed from red to yellow indicating negative
photochromism; b, with time lapse, color changed from red to yellow; c, with time lapse, after 90 min, lmax 455 nm disappeared
indicating negative photochromism; d, with time lapse, no peaks displacement occurred only the intensity of peaks decreases; e, after
60 min, lmax 372 nm disappeared indicating photochromism behavior; f, after 5 min, lmax 541 nm disappeared; g, with time lapse,
after 60 min, lmax 482 nm disappeared; h, with time, lmax 470 and 356 lapse; i, with time lapse, after 60 min, red color changed to pale
yellow; k, no obvious change; l, after 5 min, hypsochromic was observed, 365 nm disappeared; m, with time, lmax 470 nm lapse, after
10 min lmax 354 nm appeared; n, after 5 min, hypsochromic was observed, lmax 365 nm disappeared and lmax 462 appeared,
indicating photochromic behavior; o, after 5 min, hypsochromic was observed, lmax 368 nm disappeared and lmax 465 appeared,
indicating photochromic behavior; p, with time, lmax 462 nm lapse, after 10 min lmax 350 nm appeared; w, weak.
basis of their different polarities that have been observed
(Table 1).
In 1,4-dioxane, two maximum wavelengths exhibited at
shorter and the system becomes two independent p systems:
fragment N contains two electrons (4n þ 2), n ¼ 0 and fragment
M contains six electrons, n ¼ 1. The C3–C4 and C5–C6 bond orders
are calculated to be 1.3485 and 1.3645, respectively, while similar
measurements for C3–C4, C5–C6, and C7–C8 for cis-retinal
(Scheme 1) confirm the similar decrease of bond length for
C5–C6 compared to the other double bonds and the order of
bond lengths is 1.3495, 1.3435, and 1.3525. Thus, a formal charge
separation predicts that the rotational TS consists of an N cation
and an M anion. This sudden polarization is responsible for the
large change in dipole moment and hence the electrical pulse
responsible for 2Z to 2E translation (Scheme 3).[31,32]
*
*
lmax ¼ 420 and 472 nm related to the p–p and n–p for pale
yellow form 2a. The absorption spectra of the 2a dye were
examined ina series of polar and non-polar solvents and are shown
to be sensitive to their local solvent environment. As shown
in Table 1, an increase in the polarity of solvents has caused a
rather bathochromic shift in absorption maxima of all dyes. The
experimental result indicated that a strong 2Ered/2Eyellow form
occurred in relatively nonpolar solvents. In solvents of low polarity,
the proportion of the 2Eyellow form increases, whereas nonpolar
solvents displace the equilibrium toward the 2Eyellow (Scheme 5).
The photochromism not only affects the 2E form through the
solvent polarity and specific interactions between the solvent and
the solute, but may also involve the dye chemical structure. The
spectral data show the importance of the location of the NO2
groups attached to the aromatic skeleton in these compounds.
Positive absorption anisotropy is found for 2E in the liquid
crystalline solution. LD measurement indicates that the transition
EXPERIMENTAL
The UV/Vis absorption spectra in the range of 300–700 nm (EtOH,
C ¼ 10ꢀ4–10ꢀ6 M) as well as the position of absorption band
maxima were measured with Shimadzu UV-2100 spectropho-
tometer. Chemicals were purchased from Fluka, Merck, and
Aldrich. Melting points are uncorrected and determined by
Mettler Fp5 melting point apparatus. Products were character-
ized by 1H, 13C NMR, TLC, and m. p. All NMR data were recorded in
CDCl3 using a Bruker Avance 500-MHz spectrometer. Chemical
shifts are reported in ppm (d) using deuterated solvents as
internal references. Elemental analyses were made by a Carlo–
Erba EA1110 CNNO-S analyzer and agreed with the calculated
*
is of p–p type (i.e. transition moment lies in the plane of the
molecule).[31,32] The UV-Vis spectra in Table 1 point out that 2E
red converted to the 2E yellow via negative photochromism. In
this phenomenon, when A converted to the B the lmax of A is
higher than B.
According to the MOPAC-AM1 calculation, the cis double bond
would be in the 3,4-position. In the middle of the 3,4 bond
rotation, conjugation is lost and the bond length becomes
Scheme 5.
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Copyright ß 2009 John Wiley & Sons, Ltd.
J. Phys. Org. Chem. 2010, 23 266–270

PHOTOCHROMIC BEHAVIOR OF NEWLY SYNTHESIZED DYES
values. Bond lengths’ order was measured using Chem 3D ultra
1985–2003, Cambridge soft corporation, 100 Cambridge park
Drive, Cambridge, MA 02140, USA.
(1.4 mmol) pyrrolidine in 3 ml absolute MeOH dropwise for
10 min. On adding a first drop of pyrrolidine, the color of the
solution changed to dark red. The reaction mixture was cooled,
filtered, and recrystallized from CH2Cl2 and N-hexane several
times. Greenish metallic crystals of 2b (E) (0.37 g (.075 mmol) 75%
yield, M.P ¼ 158–162 8C) were collected. IR (KBr): 3040, 2950,
1616, 1514, 1492, 1469, 1321, 1215, 1170, 1105, 956, 904, 862,
727 cmꢀ1; 1H NMR (500 MHz, CDCl3): d; 1.98 (br, 4H), 3.34 (br, 4H),
5.4 (t, J ¼ 12.2 Hz, 1H), 7.03 (d, J ¼ 12.1 Hz, 1H), 7.08 (d, J ¼ 8.87 Hz,
1H), 7.12 (d, J ¼ 12.5 Hz, 1H), 7.29–7.32 (m, 1H), 7.41–7.44 (t,
J ¼ 7.5 Hz, 2H), 7.47 (d, J ¼ 7.43 Hz, 2H), 7.98 (s, 1H), 8.3 (dd, J ¼ 2.4,
8.84 Hz, 1H), 8.74 (d, J ¼ 2.4 Hz, 1H) ppm; anal. calcd. for
C21H20N4O4; C, 64.28; H, 5.14; N, 14.28; found C, 64.29; H, 5.16;
N, 14.30. Exact mass: (Mþ): calcd. for 392.1485, found 392.1488.
3-Phenyl-1-(2,4-dinitrophenyl)-pyridinium chloride (1b)
To a solution of 1-chloro-2,4-dinitrobenzene (1.42 g, 7.01 mmol) in
acetone (10 ml) was added 3-phenylpyridine (1.0 ml, 6.97 mmol).
The reaction was heated at reflux for 48 h. The solvent was
removed under reduced pressure and the red residue was stirred
in hexanes. The precipitated product was collected by vacuum
filtration to provide pure pyridinium salt 1b as a reddish brown
solid (2.23 g, 6.25 mmol, 90%). 1H NMR (CDCl3, 500 MHz) d 9.91 (s,
1H), 9.41 (d, J ¼ 6.0, 1H), 9.30 (d, J ¼ 8.3, 1H), 9.15 (d, J ¼ 2.2, 1H),
9.02 (dd, J ¼ 8.7, 2.4, 1H), 8.50–8.55 (m, 2H), 7.99 (d, J ¼ 7.3, 2H),
7.59–7.65 (m, 3H); 13C NMR (CDCl3, 125 MHz) d 149.2, 145.6,
144.23, 144.17, 143.0, 139.2, 138.7, 132.5, 132.3, 130.6, 130.2,
129.6, 128.0, 127.6, 121.3; IR (KBr) 3202, 3129, 2994, 2901,
1609 cmꢀ1; M. p. ¼ 182–183 8C; anal. calcd. for C17H12N3Oþ4 ; C,
63.35; H, 3.75; N, 13.04; found C, 63.36; H, 3.76; N, 13.04. Exact
mass: (Mþ) C17H12ClN3O4, 357.0516, found 357.0519.
Preparation of (6Z)-N-((2E,4E)-5-(diethylamino) penta-2,4-
dienylidene)-2,4-dinitrobenzenamine 3a
To a 100 ml beaker was added 0.3 g (1 mmol) of the 2,4-
dinitrophenyl pyridinium chloride (1a) dissolved in 5 ml absolute
MeOH. The resulting mixture was cooled to ꢀ10 8C and allowed
to stir for 15 min. To this was added a solution of 0.073 g (1 mmol)
pyrrolidine in 2 ml absolute MeOH dropwise for 10 min. On
adding a first drop of diethylamine, the color of the solution
changed to dark green. The reaction mixture was cooled, filtered,
and recrystallized from CH2Cl2 and N-hexane several times.
Greenish metallic crystals of 3a (E) (0.2 g (0.62 mmol) 62% yield,
M. p. ¼ 156–159 8C) were collected. IR (DMSO solvent): 2995,
2912, 1660, 1436, 1408, 1311.5, 700, 669 cmꢀ1; 1H NMR (500 MHz,
CDCl3): d; 1.25 (t, J ¼ 7.2 Hz, 6H), 3.3 (q, J ¼ 7.2 Hz, 4H), 5.37 (t,
J ¼ 12.1 Hz, 1H), 6.11 (dd, J ¼ 9.9, 14 Hz, 1H), 6.8N (d, J ¼ 12.6 Hz,
1H), 7.02 (dd, J ¼ 11.6, 14 Hz, 1H), 7.11 (d, J ¼ 8.8 Hz, 1H), 7.95 (d,
J ¼ 9.9 Hz, 1H), 8.33 (dd, J ¼ 2.5, 8.8 Hz, 1H), 8.7 (d, J ¼ 2.5 Hz, 1H)
ppm; anal. calcd. for C15H18N4O4; C, 56.60; H, 5.70; N, 17.60; found
C, 56.62; H, 5.71; N, 17.62. Exact mass: (Mþ): calcd. for 318.1328,
found 318.1333.
2,4-Dinitrophenyl pyridinium chloride (1a)
Pure pyridinium salt 1a as a cream solid (2. 3 g, 8.12 mmol, 82%).
M. p. ¼ 197–200 8C (lit. M. p. ¼ 196–200)[3–6]; anal. calcd. for
C11H8ClN3O4; C, 46.91; H, 2.86; Cl, 12.59; N, 14.92; found C, 46.90;
H, 2.85; Cl, 12.57; N, 14.93; 1H NMR (CDCl3, 500 MHz); IR (KBr):
3050, 1631, 1608.5, 1542, 1477.4, 1344, 1313, 1271, 781, 675,
1
520 cmꢀ1. H NMR (500 MHz, D2O) d; 8.2 (dd, J ¼ 1.1, 8.7 Hz, 1H),
8.3 (t, J ¼ 6.7 Hz, 2H), 8.87–8.91 (m, 2H), 9.1 (d, J ¼ 6.5 Hz, 2H), 9.32
(S, 1H) ppm; Exact mass: (Mþ) calcd. for C11H8ClN3O4, 282.0174,
found 282.0174.
Preparation of (6Z)-2,4-dinitro-N-((2E,4E)-5-(pyrrolidin-1-
yl)penta-2,4-dienylidene) benzenamine 2a (E)
To a 100 ml beaker was added 0.3 g (1 mmol) of the 2,4-
dinitrophenyl pyridinium chloride (1a) dissolved in 5 ml absolute
MeOH. The resulting mixture was cooled to ꢀ10 8C and allowed
to stir for 15 min. To this was added a solution of 0.07 g (1 mmol)
pyrrolidine in 2 ml absolute MeOH dropwise for 10 min. On
adding a first drop of pyrrolidine, the color of the solution
changed to dark red. The reaction mixture was cooled, filtered,
and recrystallized from MeOH and N-hexane several times.
Greenish metallic crystals of 2a (E) (0.24 g (0.75 mmol) 75% yield,
M. p. ¼ 158–162 8C) were collected. IR (KBr): 2923, 2856, 1614,
1512, 1490, 1460, 1334.6, 1311.5, 1217, 1184, 1118.6, 1076.21,
954.7, 906.5 cmꢀ1; 1H NMR (500 MHz, CDCl3): d; 2 (br, 4H), 3.4 (br,
4H), 5.3 (t, J ¼ 12.1 Hz, 1H), 6.13 (dd, J ¼ 9.9, 14 Hz, 1H), 6.99–7.05
(m, 2H), 7.12 (d, J ¼ 8.8 Hz, 1H), 7.96 (d, J ¼ 9.8 Hz, 1H), 8.33 (dd,
J ¼ 2.5, 8.8 Hz, 1H), 8.7 (d, J ¼ 2.5 Hz, 1H) ppm; anal. calcd. for
C15H16N4O4; C, 56.96; H, 5.10; N, 17.71; found C, 56.97; H, 5.12; N,
17.73. Exact mass: (Mþ) calcd. for 316.1172, found 316.1174,
316, 233, 181 (100), 135, 83.
Preparation of (6Z)-N-((2E,4E)-5-(diethylamino)-2-
phenylpenta-2,4-dienylidene)-2,4-dinitrobenzenamine 3b
To a 100 ml beaker was added 0.5 g (1.4 mmol) of the 2,4-
dinitrophenyl 3-phenylpyridinium chloride (1b) dissolved in 5 ml
absolute MeOH. The resulting mixture was cooled to ꢀ10 8C and
allowed to stir for 15 min. To this was added a solution of 0.1 g
(1.4 mmol) diethylamine in 3 ml absolute MeOH dropwise for
10 min. On adding a first drop of diethylamine, the color of the
solution changed to deep green. The reaction mixture was
cooled, filtered and recrystallized from CH2Cl2 and N-hexane
several times. Greenish metallic crystals of 3b (E) (0.37 g
(0.095 mmol) 68% yield, M. p. ¼ 146–150 8C) were collected. IR
(KBr): 2920, 2854.4, 1604, 1530, 1452, 1373, 1311, 1245, 1166,
1143.7, 1118.6, 1101, 1062.7, 860 cmꢀ1; 1H NMR (500 MHz, CDCl3):
d; 1.2 (br, 6H), 3.2 (br, 4H), 5.48 (t, J ¼ 12.3 Hz, 1H), 6.88 (d,
J ¼ 12.4 Hz, 1H), 7.04–7.08 (m, 2H), 7.43–7.51 (m, 5H), 7.99 (5, 1H),
8.31 (dd, J ¼ 2.2, 9 Hz, 1H), 8.75 (s, 1H) ppm; anal. calcd. for
C21H22N4O4: C, 63.95; H, 5.62; N, 14.20; found C, 63.94; H, 5.60; N,
14.19. Exact mass: (Mþ): calcd. for 394.1641, found 394.1644.
Preparation of (6E)-2,4-dinitro-N-((2E,4E)-2-phenyl-5-
(pyrrolidin-1-yl)penta-2,4-dienylidene) benzenamine 2b (E)
Preparation of (2E,4E)-5-(2,4-dinitrophenylamino)
penta-2,4-dienal 4
To a 100 ml beaker was added 0.5 g (1.4 mmol) of the 2,4-
dinitrophenyl 3-phenylpyridinium chloride (1b) dissolved in 5 ml
absolute MeOH. The resulting mixture was cooled to ꢀ10 8C and
allowed to stir for 15 min. To this was added a solution of 0.1 g
To a 50 ml round-bottom flask was added 0.5 g (1.8 mmol) of the
2,4-dinitrophenyl pyridinium chloride (1a) dissolved in 5 ml
J. Phys. Org. Chem. 2010, 23 266–270
Copyright ß 2009 John Wiley & Sons, Ltd.
www.interscience.wiley.com/journal/poc

N. O. MAHMOODI ET AL.
absolute MeOH. The resulting mixture allowed stirring for 15 min
at room temperature. To a 20 ml beaker was added 0.13 g
(1.8 mmol) pyrrolidine dissolved in 3 ml MeOH. To this solution
was added a solution of 0.1 g (1 mmol) sodium carbonate
dissolved in 5 ml water. The resulting solution was added
dropwise for 10 min to the solution of 50 ml flask. On adding a
first drop of pyrrolidine, the color of the solution changed to dark
red. The reaction mixture was cooled, filtered, and recrystallized
from acetone and water several times and finally washed with
cooled MeOH. Red metallic crystals of 4 (0.4 g (1.53 mmol) 85%
yield, M. p. ¼ 176–178 8C) were collected. IR (KBr): 3290.7, 3113.3,
[9] N. O. Mahmoodi, H. Kiyani, Bull. Korean S Chem. Soc. 2004, 25, 1417–
1420.
[10] M. R. Yazdanbakhsh, N. O. Mahmoodi, S. Dabiry, Mendeleev Commun.
2006, 3, 192–194.
[11] N. O. Mahmoodi, M. R. Yazdanbakhsh, H. Kiyani, B. Sharifzadeh, J.
Chin. Chem. Soc. 2007, 54, 635–641.
[12] H. Kiyani, N. O. Mahmoodi, K. Tabatabaeian, M. A. Zanjanchi, Mende-
leev Commun. 2009, 19, 203–205.
[13] H. Kiyani, N. O. Mahmoodi, K. Tabatabaeian, M. A. Zanjanchi, J. Phys.
Org. Chem. 2009, 22, 559–567.
[14] M. Arvand, M. Moghimi, A. Afshari, N. Mahmoodi, Anal. Chim. Acta
2006, 579, 102–108.
[15] M. A. Zanjanchi, M. Arvand, A. Islamnezhad, N. O. Mahmoodi, Talanta
2007, 74, 125–131.
[16] A. M. Lucchese, L. Marzorati, Quim. Nova 2000, 23, 641–652.
[17] L. Atmaca, A. Onen, Y. Yagci, Eur. Polym. J. 2001, 37, 677–682.
[18] J. Pernak, J. Kalewska, H. Ksycinska, J. Cybulski, Eur. J. Med. Chem.
2001, 36, 899–907.
3068, 1601, 1518, 1336.7, 1240.3, 1163, 1128.4, 989.5, 709.8 cmꢀ1
;
1H NMR (500 MHz, DMSO): d; 6.09 (dd, J ¼ 8.1, 15 Hz, 1H), 6.64 (t,
J ¼ 12 Hz, 1H), 7.43 (dd, J ¼ 11.5, 15 Hz, 1H), 7.78 (d, J ¼ 9.5 Hz, 1H),
7.98 (d, J ¼ 12.7 Hz, 1H), 8.43 (dd, J ¼ 2.7, 9.5 Hz, 1H), 8.83 (d,
J ¼ 2.7 Hz, 1H), 9.47 (d, J ¼ 8.1 Hz, 1H), 10.43 (br, 1H) ppm; 13C NMR
(125 MHz, DMSO): d; 114.3, 117.9, 123.8, 128.7, 130.7, 138.4, 139.3,
142.5, 153.4 ppm; anal. calcd. for C11H9N3O5; C, 50.20; H, 3.45; N,
15.96; found C, 50.21; H, 3.44; N, 15.94. Exact mass: (Mþ): calcd. for
263.2063, found 263.2065.
[19] M. Eda, M. J. Kurth, Tetrahedron Lett. 2001, 42, 2063–2068.
[20] R. Palin, J. K. Clark, P. Cowley, A. W. Muir, E. Pow, A. B. Prosser, R. Taylor,
M. Q. Zhang, Bioorg. Med. Chem. Lett. 2002, 12, 2569–2572.
[21] E. F. V. Scriven, Chem. Soc. Rev. 1983, 12, 129–133.
[22] J. Pernak, J. Rogoza, Arkivoc 2000, 1, 889–904.
[23] Y. S. Wong, C. Marazano, D. Gnecco, B. C. Das, Tetrahedron Lett. 1994,
35, 707–710.
[24] M. Mehmandoust, C. Marazano, B. C. Das, J. Chem. Soc. Chem.
Commun. 1989, 1185–1187.
´
[25] A. Diez, L. Vilaseca, I. Lopez, M. Rubiralta, C. Marazano, D. S. Grierson,
REFERENCES
H. P. Husson, Heterocycles 1991, 32, 2139–2149.
[26] D. L. Comins, P. Joseph, R. R. Boehring, J. Am. Chem. Soc. 1994, 116,
4719–4728.
[27] L. Robertson, R. C. Hartley, Tetrahedron 2009, 65, 5284–5292.
[28] E. N. Marvell, G. Caple, I. Shahidi, J. Am. Chem. Soc. 1970, 92, 5641–
5645.
[1] Y. Chen, M-Li. Pang, K.-G. Cheng, Y. Wang, J. Han, Z. J. He, J. B. Meng,
Tetrahedron 2007, 63, 4319–4327 (and references therein).
[2] H. Durr, H. Bouas-Laurent (Eds), Photochromism. Molecules and
Systems, Elsevier, Amsterdam, 2003.
[3] T. Zincke, Liebigs Ann. Chem. 1903, 330, 361–374.
[4] T. Zincke, Liebigs Ann. Chem. 1904, 333, 296–345.
[5] T. Zincke, W. Wurker, Liebigs Ann. Chem. 1905, 338, 107-L 141.
[6] W. Konig, J. Prakt. Chem. 1904, 69, 105–137.
[29] E. N. Marvell, I. Shahidi, J. Am. Chem. Soc. 1970, 92, 5646–5649.
[30] E. N. Marvell, G. Caple, I. Shahidi, Tetrahedron Lett. 1967, 8, 277–280.
[31] G. Haran, E. A. Morlino, J. Matthes, R. H. Callender, R. M. Hochstrasser,
J. Phys. Chem. A 1999, 103, 2202–2208.
[7] N. O. Mahmoodi, M. A. Zanjanchi, H. Kiyani, J. Chem. Res. 2004, 6, 438–
440.
[8] N. O. Mahmoodi, K. Tabatabaeian, M. Arvand, H. Kiyani, B. Sharifza-
deh, Russ. J. Org. Chem. in press.
[32] H. Kandori, H. Sasaabe, K. Nakanishi, T. Yoshizawa, T. Mizukami, Y.
Shichida, J. Am. Chem. Soc. 1996, 118, 1002–1006.
[33] C. Reichardt, Solvents and Solvent Effects in Organic Chemistry (3rd
edn), Wiley-VCH, Weinheim, 2002.
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