Synthesis of symmetrical cyanine dyes with two N-ammonioalkyl groups

Article abstract of DOI:10.1016/j.tet.2013.05.015

Synthesis of new symmetrical mono-, tri-, and pentamethine cyanine dyes with two N-ammonioalkyl substituents was developed. In the last step of the synthesis, conditions for the removal of the phthalimide protecting group in cyanine dyes using hydrazine m

Full text of DOI:10.1016/j.tet.2013.05.015

Tetrahedron 69 (2013) 5898e5907
Contents lists available at SciVerse ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Synthesis of symmetrical cyanine dyes with two N-ammonioalkyl
groups
,
a
a
a
Sergey P. Gromova , Marina V. Fomina , Alexander S. Nikiforov , Artem I. Vedernikov ,
*
Lyudmila G. Kuz’mina b, Judith A.K. Howard c
a Photochemistry Center, Russian Academy of Sciences, 7A-1 Novatorov str., Moscow 119421, Russian Federation
b N.S. Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, 31 Leninsky Prosp., Moscow 119991, Russian Federation
c Chemistry Department, University of Durham, South Road, Durham DH1 3LE, UK
a r t i c l e i n f o
a b s t r a c t
Article history:
Synthesis of new symmetrical mono-, tri-, and pentamethine cyanine dyes with two N-ammonioalkyl
substituents was developed. In the last step of the synthesis, conditions for the removal of the phtha-
limide protecting group in cyanine dyes using hydrazine monohydrate and an ethanol solution of MeNH2
were selected. The obtained dyes with ammonium groups capable of hydrogen bonding are promising as
components of light-sensitive supramolecular systems.
Received 29 December 2012
Received in revised form 23 April 2013
Accepted 9 May 2013
Available online 14 May 2013
Ó 2013 Elsevier Ltd. All rights reserved.
Keywords:
Cyanine dye
Synthesis
Ammonioalkyl groups
Phthalimide protecting group
Methylamine
1. Introduction
increase in the number of intermolecular hydrogen bonds formed.8
However, published examples of using a primary ammonium group
Cyanine dyes are well-known for their wide use in photographic
materials;1 however, the interest in this class of compounds per-
sists because they have found use as luminophores,2 luminescence
labels in biology and medicine,3 as parts of the recording medium
in optical discs,4 and components of supramolecular structures.5
The sensitivity of absorption and fluorescence of cyanine dyes to
the medium determines good prospects for their use as probes, not
only to study endogenous biomolecules but also to study the
structure, kinetics, and thermodynamics of the formation of ag-
gregates, supramolecular complexes and assemblies.5e,6
The hydrogen bond is a principal intermolecular interaction,
resulting in the formation of stable supramolecular systems.7 Using
hydrogen bonds, which are rather strong and definitely directed,
for supramolecular assembly, it is possible to design promising
supramolecular objects with a specified structure and diverse
properties. Published data describe supramolecular complexes and
assemblies that have been made by means of hydrogen bonds in-
volving amide, hydroxyl, carboxyl, amino, and other groups. The
strength of the obtained structures regularly increases following an
able to form three hydrogen bonds, which are often encountered in
natural systems, for self-assembly of supramolecular light-sensitive
systems are very few.
In this regard, of particular interest are cyanine dyes containing
ammonioalkyl substituents at the nitrogen atoms of the heterocy-
clic residues, which creates new opportunities for their self-
assembly to light-sensitive supramolecular systems based on hy-
drogen bonding.
2. Results and discussion
Methods for the preparation of cyanine dyes are now well de-
veloped, and are based on the condensation of quaternary salts of
heterocyclic bases containing an active methyl group in position 2 or
4 with C-electrophiles. The condensation is performed in the pres-
ence of bases.1b,c,9 Cyanine dyes containing terminal ammonium
groups in N-substituents cannot be prepared by direct condensation
of quaternary heterocyclic salts containing ammonioalkyl groups
due to side reactions. The use of a protecting group makes it possible
to avoid undesirable processes. In our investigations, phthalimide
protection, which is stable against the bases and electrophilic re-
agents used, proved to be most suitable.10
* Corresponding author. Tel.: þ7 495 935 0116; fax: þ7 495 936 1255; e-mail
address: spgromov@mail.ru (S.P. Gromov).
0040-4020/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.tet.2013.05.015

S.P. Gromov et al. / Tetrahedron 69 (2013) 5898e5907
5899
Some unsymmetrical mono-, meso-methyltri- and pentam-
R2
Me
R2
Me
ethine cyanine dyes containing phthalimide groups or amino group
hydrobromides as terminal groups on the N-substituents of het-
erocyclic residues have been reported.11 However, these dyes have
not been isolated in a pure state and their structures have not been
confirmed by physicochemical characteristics. In this connection,
the purpose of our study is the development of synthesis, isolation
methods, and characterization of symmetrical cyanine dyes with
ammonium groups on the N-substituents of the heterocyclic resi-
dues. The quaternary benzothiazolium, 3H-indolium, and 1H-
benzo[e]indolium salts needed for dye synthesis were obtained
based on known procedures by quaternization of heterocyclic
bases.12
Me
Me
R1
Me
Me
R1
iorii
+ R3Br
N+
-
N
ClO4
R3
6a-c
7a,b
3c,d
O
R3=
(CH ) N
n
2
O
6:R1,R2=H,n=3(a),R1,R2=H,n=4(b);
R1-R2=C4H4;n=3(c)
7:R1,R2=H(a),C4H4(b)
The initial 2-thiobenzothiazolium salts 1a,b were prepared by
fusing together benzothiazole-2-thiol 2 with 3-phthalimidopropyl
or 6-phthalimidohexyl tosylate (3a,b) (Scheme 1).
Scheme 3. Synthesis of 3H-indolium and 1H-benzo[e]indolium salts 6aec. Reagents
and conditions: (i) 1. MeCN, argon, reflux; 2. HClO4 (70%, aq), EtOH (6a: 51%; 6b: 85%
yield); (ii) 1. MeCN, argon, sealed tube, 110 ꢀC; 2. HClO4 (70%, aq), EtOH (6c: 40% yield).
S
S
N
i
SR
SH + ROTs
N+
R
1a,b
OTs-
S
+
S
iorii
1a,b + 4a,c
N
R
N
2
3a,b
X-
8a,b
R
O
(CH ) N
R=
n
2
O
O
(CH ) N
R=
n
2
1a, 3a:n=3
1b, 3b:n=6
O
8:n=3,X=Br(a);n=6,X=ClO4 (b)
Scheme 1. Synthesis of 2-thiobenzothiazolium salts 1a,b. Reagents and conditions: (i)
heating, 140 ꢀC (1a: 70%; 1b: 54% yield).
Scheme 4. Synthesis of monomethine cyanine dyes 8a,b. Reagents and conditions: (i)
Et3N, EtOH, reflux (8a: 60% yield); (ii) 1. Et3N, EtOH, reflux; 2. HClO4 (70%, aq), EtOH
(8b: 61% yield).
Quaternary salts 4aec were prepared by fusing together
phthalimidoalkyl derivatives 3bed with 2-methylbenzothiazole 5.
Perchlorate salts 4d,e were obtained by treating the corresponding
bromides with perchloric acid in methanol (Scheme 2).
R1 R2
R2 R1
Y
Y
+
iorii
S
N+
R
4a-c
S
N+
R
4d,e
4d, 6a,c
S
N
i
ii
N
N
Me
X-
Me
ClO4
Me + RX
R3
R3
-
-
ClO4
9a-c
(for4a,b)
5
3b-d
O
3b, 4c:X=OTs,n=6
3c, 4a:X=Br,n=3
3d, 4b:X=Br,n=4
4d:n=3
O
R3 =
(CH2)3N
(CH ) N
R=
n
2
O
O
9:Y=S,R1,R2 =H(a);
4e:n=4
Y = CMe2,R1,R2 =H(b);
Scheme 2. Synthesis of 2-methylbenzothiazolium salts 4aee. Reagents and condi-
tions: (i) heating, 140e150 ꢀC (4a: 92%; 4b: 80%; 4c: 67% yield); (ii) HClO4 (70%, aq),
MeOH (4d: 96%; 4e: 94% yield).
Y = CMe2,R1-R2 =C4H4 (c)
Scheme 5. Synthesis of trimethine cyanine dyes 9aec. Reagents and conditions: (i)
CH(OEt)3, Py, reflux (9a: 60%; 9b: 33% yield); (ii) CH(OEt)3, Et3N, Ac2O, reflux (9c: 63%
yield).
Salts 6aec were prepared by the reaction of heterocyclic bases
7a,b with phthalimidoalkyl derivatives 3c,d; the reaction was car-
ried out in acetonitrile under inert atmosphere (Scheme 3).
Benzothiazole monomethine dyes 8a,b containing phthalimi-
doalkyl substituents at the nitrogen atoms were synthesized using
a known procedure,13 by triethylamine-induced condensation of
heterocyclic salts 1a,b and 4a,c in ethanol (Scheme 4).
Trimethine dyes 9aec containing phthalimidoalkyl substituents
at nitrogen atoms were prepared using a described procedure14 by
the reaction of quaternary salts 4d, 6a,c with triethyl orthoformate
in pyridine or in acetic anhydride induced by triethylamine
(Scheme 5). The use of a fourfold excess of triethyl orthoformate
increased the yields of the target dyes.
Pentamethine dyes were prepared using 2-amino-1-
methylpyrimidinium perchlorate. For this purpose, 2-amino-1-
methylpyrimidinium iodide, prepared by a known procedure,15
was converted to perchlorate 10 by treatment with an excess of
HClO4 in methanol (Scheme 6).
N
+
N
+
i
N
NH2
I-
N
NH2
-
Me
Me
ClO4
10
Scheme 6. Synthesis of salt 10. Reagents and conditions: (i) HClO4 (70%, aq), MeOH
(10: 76% yield).

5900
S.P. Gromov et al. / Tetrahedron 69 (2013) 5898e5907
In the synthesis of pentamethine dyes, it is desirable to use 2-
amino-1-methylpyrimidinium salt as the perchlorate, because the
second heterocyclic salt is used as the perchlorate, and thus iodide
impurity in the target dye can be avoided. Furthermore, the con-
version of 2-amino-1-methylpyrimidinium iodide to the perchlo-
rate is an additional procedure for purifying this salt.
Pentamethine dyes 11aec were synthesized by condensation of
heterocyclic salts 4e, 6a,b with 2-amino-1-methylpyrimidinium
perchlorate 10 induced by triethylamine similarly to the method
reported previously.15 The reaction was carried out in pyridine in
the case of thiadicarbocyanine 11a or in acetic anhydride in the case
of indodicarbocyanines 11b,c (Scheme 7).
4e, 6a,b 10
+
(a)
i
Y
Y
+ClO4
N
R
N
R
-
11a-c
O
(CH ) N
R=
n
2
O
(b)
11:Y=S,n=4(a);Y=CMe2,n=3(b);
Y=CMe2,n=4(c)
Scheme 7. Synthesis of pentamethine cyanine dyes 11aec. Reagents and conditions:
(i) Et3N, Py or Ac2O, reflux (11a: 30%; 11b: 48%; 11c: 70% yield).
The dyes 8b and 9a,b were prepared as single crystals, which
were studied by X-ray diffraction. These structures are shown in
Fig. 1. The chromophore part of 8b is strictly planar, the dihedral
angle between the planes of the benzothiazole residues is only 3.8ꢀ.
In both trimethine dyes, the chromophore moieties are non-planar:
the dihedral angles between the planes of the heterocyclic residues
in molecules 9a and 9b are 27.0ꢀ and 11.7ꢀ, respectively. The bond
lengths in the polymethine chain of 9b are nearly equal [1.384(3)e
ꢀꢀ
1.393(3) A], indicating effective conjugation throughout the chro-
mophore. The lower accuracy of the experiments for dyes 8b and 9a
precludes drawing definite conclusions about the distribution of
the bond lengths in the polymethine bridges, although a tendency
for greater difference between them can be noted for 9a and 9b.
This may be a consequence of greater twisting of the chromophore
in 9a caused apparently by the specific features of packing of
this dye.
(c)
Fig. 1. The cations of dyes in structures of (a) 8b$1.75H2O, (b) 9a$0.6CH2Cl2$0.4CHCl3
and (c) 9b$2MeCN. Thermal anisotropic ellipsoids are drawn at the (a) 40% and (b, c)
50% probability level.
region in these stacks involves mainly the benzothiazolium resi-
dues. The distances between the planes of the adjacent molecules
of 9a is w3.4 A. In the crystal packing of dye 9b, the chromophores
In dyes 9a,b, the trimethine bridge exists in the transoid con-
ꢀ
figuration, the
a
-H atoms pointing in the same direction as the N-
substituents. Another common structural feature of all dyes is
orientation of both N-substituents in the same direction in the
chromophore plane. This geometry of the cyanine dyes in the
crystals is characteristic.16 It follows from NMR data that this ge-
ometry is retained in solution, as indicated by intense cross-peaks
of the neighbouring molecules are remote from one another, which
is probably attributable to the steric hindrance created by the CMe2
groups of the indoleninium residues.
Cyanine dyes 12aef with ammonioalkyl substituents at the
heterocyclic nitrogen atoms were prepared after removal of the
protecting groups from 8b, 9aec, and 11b,c. The most common
method for removing the phthalimide protecting group is hydra-
zinolysis, which proceeds rather readily.10a,17 While selecting con-
ditions for deprotection, we looked to the procedure reported
previously.18 The reaction was carried out with a tenfold excess of
hydrazine monohydrate in a boiling CH2Cl2eMeOH mixture; the
reaction time varied from 3 to 6 h. The reaction afforded dyes amino
derivatives. The subsequent treatment of these products with
a solution of HClO4 gave the desired dyes 12b,c,f in 17e45% yield.
However, this method is not free from drawbacks, namely, the
between the
a
-H and CH2Nþ protons in the NOESY spectra of
dyes 9a,b, whereas cross-peaks due to coupling of CH2Nþ with
meso-H are absent. Contrarily, in the case of monomethine dye 8b,
the expected NOESY cross-peak due to the CH2Nþ and meso-H in-
teraction was found.
In the crystal of 8b, the dye cations form rather isolated cen-
trosymmetric dimers with stacking interaction between the chro-
ꢀ
mophore units, which are arranged at distance of w3.5 A. The dye
cations in the crystal of 9a are packed into strongly skewed stacks
with a centrosymmetric arrangement; the stacking interaction

S.P. Gromov et al. / Tetrahedron 69 (2013) 5898e5907
5901
laborious procedure of dye separation from 1,4-phthalazinedione
4. Experimental section
4.1. General
formed in the reaction and the unreacted hydrazine mono-
hydrate. The purification procedure must be repeated many times,
and this decreases the yields of target dyes. The phthalimide group
can also be removed by treatment with other, milder nucleophilic
reagents such as aqueous methylamine.11a While selecting the
deprotection conditions, we found that on treatment of dyes 8b,
9b,c, and 11b,c with a 38% solution of MeNH2 in absolute ethanol,
the reaction occurs under milder conditions and remaining me-
thylamine is easily distilled off under reduced pressure. N,N0-
Dimethylphthalamide is removed from the reaction mixture by
extraction into ethyl acetate. This workup is fairly facile and effi-
cient. The subsequent treatment of dye amino derivatives with
a solution of HClO4 provides the desired dyes in high purity in good
yields (up to 51%) (Scheme 8, Table 1).
Melting points were determined with a MEL-Temp II apparatus
in a capillary and are uncorrected. 1D 1H and 13C NMR spectra were
recorded on a Bruker DRX-500 instrument (500.13 and 125.76 MHz,
respectively) as solutions in DMSO-d6 using the solvent as an in-
ternal reference (dH 2.50, dC 39.40, respectively); 2D homonuclear
1He1H COSY and NOESY spectra and heteronuclear 1He13C COSY
spectra (HSQC and HMBC) were used to assign the proton and
carbon signals. Absorption spectra were recorded on Shimadzu UV-
3101PC and Agilent Cary 4000 spectrophotometers in the range of
250e800 nm with an increment of 1 nm (Cdye¼1ꢁ10ꢂ5 M, 1-cm
quartz cell, room temperature). Emission spectra were recorded
on a Shimadzu RF-5301PC spectrofluorimeter in the range of
430e800 nm with an increment of 1 nm (Cdye¼1ꢁ10ꢂ5 M, 1-cm
quartz cell, room temperature). IR spectra in KBr pellets were
recorded on a Bruker IFS-113V spectrophotometer. High resolution
ESI mass spectra were measured on a MicrOTOF II instrument
(Bruker Daltonics) in the range of m/z¼50e3000 for positive ions
(MeOH solution inlet, nitrogen gas flow, 4500 V capillary voltage).
Elemental analyses were performed at the Microanalytical Labo-
ratory of A.N. Nesmeyanov Institute of Organoelement Compounds
(Moscow, Russian Federation). Tosylates 3a,b and 2-amino-1-
methylpyrimidin-1-ium iodide were prepared by known
procedures.11a,15,20
8b, 9a-c, 11b,c
iorii
R1 R2
R1
R2
N
Y
Y
( )
+
N
-
m
3ClO4
(CH )
(CH2)n
NH3+
n
2
NH3+
4.2. Synthesis of 2-thiobenzothiazolium salts 1a,b
12a-f
Scheme 8. Deprotection of the phthalimide group. Reagents and conditions: (i) 1. 38%
solution of MeNH2 in abs EtOH; 2. HClO4 (70%, aq), EtOH; (ii) 1. N2H4$H2O, CH2Cl2/
MeOH, reflux; 2. HClO4 (70%, aq), EtOH.
A mixture of 2-mercaptobenzothiazole 2 (167 mg, 1 mmol) and
compounds 3a,b (2 mmol) was heated at 140 ꢀC (oil bath) for 20 h.
After cooling to room temperature, the resulting mass was washed
with benzene and dried in vacuo. Yield 1a: 499 mg (70%). Yield 1b:
430 mg (54%). Compounds 1a,b were used without further
purification.
Table 1
Yields of dyes 12aef produced via Scheme 8
Dye
m
n
Y
R1, R2
Yield % (i)
44
Yield % (ii)
12a
12b
12c
12d
12e
12f
0
1
1
1
2
2
6
3
3
3
3
4
S
S
H, H
H, H
H, H
C4H4
H, H
H, H
0
17
45
4.2.1. 3-[3-(1,3-Dioxo-1,3-dihydro-2H-isoindol-2-yl)propyl]-2-{[3-
(1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)propyl]thio}-1,3-benzothia-
zol-3-ium 4-methylbenzenesulfonate (1a). Salt 1a was isolated as
a brownish oil. Found C, 57.38; H, 4.57; N, 4.37. C36H31N3O7S3$T-
sOH$H2O requires C, 57.13; H, 4.57; N, 4.65%. IR (KBr) 1711 (C]
CMe2
CMe2
CMe2
CMe2
40
25
42
51
37
þ
O) cmꢂ1; MS (ESI): found m/z 542.1190 (calcd for C29H24N3O4S2
542.1208); dH (DMSO-d6) 2.14e2.24 (4H, m, 2CH2), 2.28 (3H, s, Me),
3.65 (2H, br t, CH2S), 3.74e3.81 (4H, m, 2CH2N), 4.69e4.72 (2H, m,
CH2Nþ), 7.12 (2H, d, J 7.7 Hz, 3000-H, 5000-H), 7.50 (2H, d, J 7.7 Hz, 2000-H,
6000-H), 7.70e7.73 (1H, m, 6-H), 7.81e7.87 (9H, m, 5-H, 40-H, 50-H, 60-
H, 70-H, 400-H, 500-H, 600-H, 700-H), 8.29 (1H, d, J 8.6 Hz, 4-H), 8.37 (1H,
d, J 8.2 Hz, 7-H); dC (DMSO-d6) 20.70 (Me), 25.88 and 26.70 (2CH2),
33.67 and 34.81 (2CH2N), 35.98 (CH2S), 47.91 (CH2Nþ), 115.60 (4-C),
122.97 and 123.01 (2ꢁ50-C, 2ꢁ60-C), 124.12 (7-C), 125.43 (2000-C, 6000-
C), 128.08 (3000-C, 5000-C), 128.24 (6-C), 128.64 (7a-C), 129.27 (5-C),
131.59 and 131.68 (3a0-C, 7a0-C, 3a00-C, 7a00-C),134.32 and 134.36 (40-
C, 70-C, 400-C, 700-C), 137.84 (4000-C), 141.41 (3a-C), 145.21 (1000-C),
167.96 and 168.02 (10-C, 30-C, 100-C, 300-C), 179.30 (2-C).
The obtained cyanine dyes with terminal ammonium groups on
the N-substituents of heterocyclic residues can be employed as
components for the design of light-sensitive supramolecular sys-
tems. The presence of primary ammonium groups capable of
functioning as proton donors in hydrogen bonds creates the pos-
sibility for self-assembly of the dyes to supramolecular complexes
with crown or cavitand molecules having proton-acceptor groups,
for example, ether or carbonyl oxygens. We have shown that this
type of interaction gives rise to highly stable supramolecular
complexes in which unusual photochemical processes may take
place.19
3. Conclusions
4.2.2. 3-[6-(1,3-Dioxo-1,3-dihydro-2H-isoindol-2-yl)hexyl]-2-{[6-
(1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)hexyl]thio}-1,3-
benzothiazol-3-ium 4-methylbenzenesulfonate (1b). Salt 1b was
isolated as a brownish oil. Found C, 59.54; H, 5.33; N, 4.01.
C42H43N3O7S3$TsOH$H2O requires C, 59.55; H, 5.41; N, 4.25%. IR
(KBr) 1709 (C]O) cmꢂ1; MS (ESI): found m/z 626.2147 (calcd for
C35H36N3O4S2þ: 626.2147); dH (DMSO-d6) 1.29e1.64 (12H, m,
6CH2), 1.80e1.83 (2H, m, CH2), 1.88e1.91 (2H, m, CH2), 2.28 (3H, s,
Me), 3.53e3.58 (4H, m, 2CH2N), 3.59e3.62 (2H, m, CH2S), 4.58 (2H,
br t, CH2Nþ), 7.10 (2H, d, J 7.6 Hz, 3000-H, 5000-H), 7.48 (2H, d, J 7.6 Hz,
We have developed the synthesis of high-purity symmetrical
mono-, tri-, and pentamethine cyanine dyes with two ammo-
nioalkyl substituents on the heterocyclic nitrogen atoms in good
yields. Conditions for the removal of the phthalimide protection in
cyanine dyes of this type were selected. This approach to the syn-
thesis of symmetrical cyanine dyes with ammonioalkyl sub-
stituents may also open up a way to novel groups of dyes promising
as luminophores and luminescent labels in biology and medicine.

5902
S.P. Gromov et al. / Tetrahedron 69 (2013) 5898e5907
2000-H, 6000-H), 7.70e7.74 (1H, m, 6-H), 7.80e7.86 (9H, m, 5-H, 40-H,
50-H, 60-H, 70-H, 400-H, 500-H, 600-H, 700-H), 8.21 (1H, d, J 8.3 Hz, 4-H),
8.36 (1H, d, J 8.3 Hz, 7-H); dC (DMSO-d6) 20.63 (Me), 25.30, 25.43,
25.64, 26.56, 27.16, 27.34, 27.55 and 27.68 (8CH2), 35.88 (CH2S),
37.11 (2CH2N), 49.87 (CH2Nþ), 115.67 (4-C), 122.83 (2ꢁ500-C, 2ꢁ60-
C), 123.97 (7-C), 125.37 (2ꢁ200-C, 600-C), 127.91 (300-C, 500-C, 6-C),
128.58 (7a-C), 129.14 (5-C), 131.44 (3a0-C, 7a0-C, 3a00-C, 7a00-C),
134.25 (40-C, 70-C, 400-C, 700-C), 137.49 (4000-C), 141.44 (3a-C), 145.60
(1000-C), 167.81 and 167.83 (10-C, 30-C, 100-C, 300-C), 179.33 (2-C).
of the substance was attained. After cooling to 5 ꢀC, the precipitate
that formed was filtered off and washed with MeOH. Yield 4d:
420 mg (96%). Yield 4e: 423 mg (94%).
4.4.1. 3-[3-(1,3-Dioxo-1,3-dihydro-2H-isoindol-2-yl)propyl]-2-
methyl-1,3-benzothiazol-3-ium perchlorate (4d). Salt 4d was iso-
lated as white crystals. Found C, 52.29; H, 3.74; N, 6.32.
C19H17ClN2O6S requires C, 52.24; H, 3.92; N, 6.41%. Mp 248e249 ꢀC.
IR (KBr) 1719 (C]O) cmꢂ1
; dH (DMSO-d6) 2.23e2.29 (2H, m,
CH2CH2N), 3.20 (3H, s, Me), 3.85 (2H, t, J 6.8 Hz, CH2N), 4.80e4.83
(2H, m, CH2Nþ), 7.77e7.80 (1H, m, 6-H), 7.84e7.90 (5H, m, 5-H, 40-
H, 50-H, 60-H, 70-H), 8.37 (1H, d, J 8.5 Hz, 4-H), 8.41 (1H, d, J 8.2 Hz, 7-
H); dC (DMSO-d6) 16.69 (Me), 26.49 (CH2CH2N), 34.87 (CH2N), 47.17
(CH2Nþ), 116.67 (4-C), 122.90 (50-C, 60-C), 124.47 (7-C), 127.99 (6-C),
128.96 (7a-C), 129.24 (5-C), 131.70 (3a0-C, 7a0-C), 134.22 (40-C, 70-C),
140.62 (3a-C), 168.04 (10-C, 30-C), 177.51 (2-C).
4.3. Synthesis of 2-methylbenzothiazolium salts 4aec
A mixture of 2-methylbenzothiazole 5 (0.19 mL, 1.5 mmol) and
compounds 3bed (1.0 mmol) was heated at 140e150 ꢀC (oil bath) for
20 h. After cooling to room temperature, the resulting solid was
washed with hotbenzene, acetone, diethyl etheranddried in air. Yield
4a: 383 mg (92%). Yield 4b: 344 mg (80%). Yield 4c: 368 mg (67%).
4.4.2. 3-[4-(1,3-Dioxo-1,3-dihydro-2H-isoindol-2-yl)butyl]-2-
methyl-1,3-benzothiazol-3-ium perchlorate (4e). Salt 4e was isolated
as white crystals. Found C, 53.36; H, 4.26; N, 6.61. C20H19ClN2O6S
requires C, 53.28; H, 4.25; N, 6.21%. Mp 221e225 ꢀC. IR (KBr) 1714
4.3.1. 3-[3-(1,3-Dioxo-1,3-dihydro-2H-isoindol-2-yl)propyl]-2-
methyl-1,3-benzothiazol-3-ium bromide (4a). Salt 4a was isolated as
a white powder. Found C, 54.78; H, 4.07; N, 6.53. C19H17BrN2O2S
requires C, 54.68; H, 4.11; N, 6.71%. Mp 225 ꢀC (decomp.). IR (KBr)
(C]O) cmꢂ1
; dH (DMSO-d6) 1.78e1.83 (2H, m, CH2CH2N), 1.88e1.94
1705 (C]O) cmꢂ1
;
dH (DMSO-d6) 2.23e2.29 (2H, m, CH2CH2N), 3.20
(2H, m, CH2CH2Nþ), 3.21 (s, 3H, Me), 3.64 (2H, t, J 6.8 Hz, CH2N),
4.72e4.75 (2H, m, CH2Nþ), 7.79 (m, 1H, 6-H), 7.82e7.89 (5H, m, 5-H,
40-H, 50-H, 60-H, 70-H), 8.35 (1H, d, J 8.5 Hz, 4-H), 8.42 (1H, d, J 8.2 Hz,
7-H); dC (DMSO-d6) 16.72 (Me), 25.01 and 25.11 (CH2CH2), 36.80
(CH2N), 48.67 (CH2Nþ), 116.76 (4-C), 122.91 (50-C, 60-C), 124.47 (7-
C), 127.99 (6-C), 128.96 (7a-C), 129.24 (5-C), 131.52 (3a0-C, 7a0-C),
134.28 (40-C, 70-C), 140.71 (3a-C), 167.93 (10-C, 30-C), 177.26 (2-C).
(3H, s, Me), 3.85 (2H, br t, CH2N), 4.80e4.83 (2H, m, CH2Nþ),
7.77e7.80 (1H, m, 6-H), 7.84e7.90 (5H, m, 5-H, 40-H, 50-H, 60-H, 70-
H), 8.36 (1H, d, J 8.3 Hz, 4-H), 8.41 (1H, d, J 7.8 Hz, 7-H); dC (DMSO-
d6) 16.69 (Me), 26.49 (CH2CH2N), 34.87 (CH2N), 47.17 (CH2Nþ),
116.67 (4-C), 122.90 (50-C, 60-C), 124.47 (7-C), 127.99 (6-C), 128.96
(7a-C), 129.24 (5-C), 131.70 (3a0-C, 7a0-C), 134.22 (40-C, 70-C), 140.62
(3a-C), 168.04 (10-C, 30-C), 177.51 (2-C).
4.5. Synthesis of 3H-indolium and 1H-benzo[e]indolium salts
6aec
4.3.2. 3-[4-(1,3-Dioxo-1,3-dihydro-2H-isoindol-2-yl)butyl]-2-
methyl-1,3-benzothiazol-3-ium bromide (4b). Salt 4b was isolated as
a yellow powder. Found C, 55.75; H, 4.45; N, 6.46. C20H19BrN2O2S
requires C, 55.69; H, 4.44; N, 6.49%. Mp 257 ꢀC (decomp.). IR (KBr)
Method A. A mixture of 2,3,3-trimethyl-3H-indole 7a (240 mL,
1.5 mmol) and compounds 3c,d (1.0 mmol) in dry MeCN (3.5 mL)
was stirred under reflux for 20 h in argon flow. The solvent was
evaporated in vacuo and the residue was dissolved in acetone and
poured into diethyl ether (100 mL). The precipitate that formed was
filtered off and washed with acetone and diethyl ether and dried in
air to give the bromide salt as a crystalline powder. Perchloric acid
1716 (C]O) cmꢂ1
; dH (DMSO-d6) 1.77e1.83 (2H, m, CH2CH2N),
1.87e1.93 (2H, m, CH2CH2Nþ), 3.21 (3H, s, Me), 3.64 (2H, t, J 6.8 Hz,
CH2N), 4.72e4.75 (2H, m, CH2Nþ), 7.77e7.80 (1H, m, 6-H), 7.83e7.89
(5H, m, 5-H, 40-H, 50-H, 60-H, 70-H), 8.36 (1H, d, J 8.5 Hz, 4-H), 8.44 (1H,
d, J 8.0 Hz, 7-H); dC (DMSO-d6) 16.72 (Me), 25.01 and 25.11 (CH2CH2),
36.80 (CH2N), 48.67 (CH2Nþ), 116.76 (4-C), 122.91 (50-C, 60-C), 124.47
(7-C), 127.99 (6-C), 128.96 (7a-C), 129.24 (5-C), 131.52 (3a0-C, 7a0-C),
134.28 (40-C, 70-C), 140.71 (3a-C), 167.93 (10-C, 30-C), 177.26 (2-C).
(70% (aq), 130 mL, 1.5 mmol) was added to a solution of the bromide
salt in hot EtOH (5 mL). The reaction mixture was cooled to 5 ꢀC and
the precipitate that formed was filtered off and washed with EtOH.
Yield 6a: 228 mg (51%). Yield 6b: 391 mg (85%).
4.3.3. 3-[6-(1,3-Dioxo-1,3-dihydro-2H-isoindol-2-yl)hexyl]-2-
methyl-1,3-benzothiazol-3-ium 4-methylbenzenesulfonate (4c). Salt
4c was isolated as a white powder. Found C, 63.14; H, 5.44; N, 5.03.
C29H30N2O5S2 requires C, 63.25; H, 5.49; N, 5.09%. Mp 180 ꢀC
Method B. A mixture of 1,1,2-trimethyl-1H-benzo[e]indole 7b
(209 mg, 1 mmol) and compound 3c (268 mg, 1.0 mmol) in dry
MeCN (1 mL) was sealed in a glass tube under argon and heated at
110 ꢀC (oil bath) for 45 h. After tube opening, the solvent was
evaporated in vacuo, and the residue was dissolved in acetone and
poured into diethyl ether (150 mL). The precipitate that formed was
filtered off and the procedure was repeated. The precipitate was
(decomp.). IR (KBr) 1709 (C]O) cmꢂ1
; dH (DMSO-d6) 1.30e1.36,
1.43e1.49, 1.56e1.62 and 1.79e1.85 (8H, 4m, 4CH2), 2.26 (3H, s,
MeAr), 3.19 (3H, s, MeHet), 3.56 (2H, t, J 7.0 Hz, CH2N), 4.68 (2H, br t,
CH2Nþ), 7.08 (2H, d, J 7.6 Hz, 300-H, 500-H), 7.47 (2H, d, J 7.6 Hz, 200-H,
600-H), 7.77e7.80 (1H, m, 6-H), 7.82e7.88 (5H, m, 5-H, 40-H, 50-H, 60-
H, 70-H), 8.31 (1H, d, J 8.6 Hz, 4-H), 8.42 (1H, d, J 8.5 Hz, 7-H); dC
(DMSO-d6) 16.64 (MeHet), 20.65 (MeAr), 25.29, 25.74, 27.48 and
27.61 (4CH2), 37.16 (CH2N), 48.98 (CH2Nþ), 116.75 (4-C), 122.88 (50-
C, 60-C), 124.47 (7-C), 125.37 (200-C, 600-C), 127.91 (300-C, 500-C), 127.96
(6-C), 128.99 (7a-C), 129.24 (5-C), 131.45 (3a0-C, 7a0-C), 134.31 (40-C,
70-C), 137.43 (400-C), 140.71 (3a-C), 145.70 (100-C), 167.85 (10-C, 30-C),
176.98 (2-C).
dissolved in EtOH (7 mL) and HClO4 (70% (aq), 100 mL, 1.15 mmol)
was added to this solution. After cooling to 5 ꢀC, the precipitate that
formed was filtered off and washed with benzene and diethyl ether
and dried in air. Yield 6c: 198 mg (40%).
4.5.1. 1-[3-(1,3-Dioxo-1,3-dihydro-2H-isoindol-2-yl)propyl]-2,3,3-
trimethyl-3H-indolium perchlorate (6a). Salt 6a was isolated as
a yellow powder. Found C, 59.01; H, 5.14; N, 6.12. C22H23ClN2O6
requires C, 59.13; H, 5.19; N, 6.27%. Mp 190e193 ꢀC. IR (KBr) 1710
(C]O) cmꢂ1
; dH (DMSO-d6) 1.54 (6H, s, CMe2), 2.20e2.26 (2H, m,
4.4. Synthesis of perchlorates 4d,e
CH2), 2.83 (3H, s, Me), 3.81 (2H, t, J 6.7 Hz, CH2N), 4.55e4.58 (2H, m,
CH2Nþ), 7.59e7.64 (2H, m, Ar), 7.82e7.89 (5H, m, Ar, 40-H, 50-H, 60-
H, 70-H), 7.99e8.01 (1H, m, Ar); dC (DMSO-d6) 13.88 (Me), 21.89
(CMe2), 26.19 (CH2CH2N), 34.76 (CH2N), 45.58 (CH2Nþ), 54.12 (3-C),
115.29 (7-C), 122.91 (50-C, 60-C), 123.39 (4-C), 128.82 (5-C), 129.33
Perchloric acid (70% (aq), 0.30 mL) was added to a solution of
salt 4a,b (1 mmol) in MeOH (30 mL). The reaction mixture was
heated and water was added dropwise until complete dissolution

S.P. Gromov et al. / Tetrahedron 69 (2013) 5898e5907
5903
(6-C), 131.73 (3a0-C, 7a0-C), 134.25 (40-C, 70-C), 140.93 (3a-C), 141.74
(7a-C), 168.02 (10-C, 30-C), 197.08 (2-C).
perchlorate (8b). Dye 8b was isolated as yellow crystals. Found C,
59.96; H, 4.71; N, 6.25. C43H41ClN4O8S2$H2O requires C, 60.09; H,
5.04; N, 6.52%. Mp 145 ꢀC; UVevis (MeCN) lmax 426 nm (
66,500 L molꢂ1 cmꢂ1); fluorescence (MeCN) lex 416 nm, lfmax
3
4.5.2. 1-[4-(1,3-Dioxo-1,3-dihydro-2H-isoindol-2-yl)butyl]-2,3,3-
trimethyl-3H-indolium perchlorate (6b). Salt 6b was isolated as
white crystals. Found C, 59.78; H, 5.38; N, 6.01. C23H25ClN2O6 re-
quires C, 59.94; H, 5.47; N, 6.08%. Mp 240e243 ꢀC. IR (KBr) 1709
475 nm. IR (KBr) 1709 (C]O) cmꢂ1
; dH (DMSO-d6) 1.27e1.33,
1.44e1.49, 1.51e1.57 and 1.72e1.78 (16H, 4m, 8CH2), 3.49 (4H, t, J
7.0 Hz, 2CH2N), 4.62 (4H, br t, 2CH2Nþ), 6.64 (1H, s, meso-H),
7.47e7.50 (2H, m, 2ꢁ6-H), 7.65e7.68 (2H, m, 2ꢁ5-H), 7.73e7.77
(8H, m, 2ꢁ40-H, 2ꢁ50-H, 2ꢁ60-H, 2ꢁ70-H), 7.88 (2H, d, J 8.4 Hz, 2ꢁ4-
H), 8.19 (2H, d, J 7.9 Hz, 2ꢁ7-H); dC (DMSO-d6) 25.54, 26.01, 26.78
and 27.70 (8CH2), 37.12 (2CH2N), 46.05 (2CH2Nþ), 82.46 (meso-C),
113.74 (2ꢁ4-C), 122.79 (2ꢁ7-C, 2ꢁ50-C, 2ꢁ60-C), 123.45 (2ꢁ6-C),
124.85 (2ꢁ7a-C), 128.51 (2ꢁ5-C), 131.40 (2ꢁ3a0-C, 2ꢁ7a0-C), 134.21
(2ꢁ40-C, 2ꢁ70-C), 140.08 (2ꢁ3a-C), 161.49 (2ꢁ2-C), 167.75 (2ꢁ10-C,
2ꢁ30-C).
(C]O) cmꢂ1
; dH (DMSO-d6) 1.53 (6H, s, CMe2), 1.75e1.80 (2H, m,
CH2CH2N), 1.87e1.93 (2H, m, CH2CH2Nþ), 2.83 (3H, s, Me), 3.64 (2H,
t, J 6.6 Hz, CH2N), 4.47 (2H, br t, CH2Nþ), 7.60e7.61 (2H, m, Ar),
7.82e7.87 (5H, m, Ar, 40-H, 50-H, 60-H, 70-H), 7.97e7.99 (1H, m, Ar);
dC (DMSO-d6) 13.84 (Me), 21.91 (CMe2), 24.46 and 24.94 (CH2CH2),
36.77 (CH2N), 47.05 (CH2Nþ), 54.07 (3-C), 115.37 (7-C), 122.93 (50-C,
60-C), 123.38 (4-C), 128.82 (5-C), 129.30 (6-C), 131.52 (3a0-C, 7a0-C),
134.31 (40-C, 70-C), 140.92 (3a-C), 141.74 (7a-C), 167.95 (10-C, 30-C),
196.73 (2-C).
4.7. Synthesis of trimethine cyanine dyes 9aec
4.5.3. 3-[3-(1,3-Dioxo-1,3-dihydro-2H-isoindol-2-yl)propyl]-1,1,2-
trimethyl-1H-benzo[e]indolium perchlorate (6c). Salt 6c was isolated
as a white solid. Found C, 62.71; H, 5.25; N, 5.59. C26H25ClN2O6
requires C, 62.84; H, 5.07; N, 5.64%. Mp 231e232 ꢀC. IR (KBr) 1711
Method A. Ethyl orthoformate (250 mL, 1.5 mmol) was added to
a boiling mixture of salt 4d, 6a (1 mmol) and pyridine (10 mL) and
the reaction mixture was stirred under reflux for 2 h. Pyridine was
evaporated in vacuo, and the residue was washed with benzene
and diethyl ether and recrystallized from abs EtOH. Yield 9a:
234 mg (60%). Yield 9b: 132 mg (33%).
(C]O) cmꢂ1
; dH (DMSO-d6) 1.77 (6H, s, CMe2), 2.26e2.32 (2H, m,
CH2CH2N), 2.94 (3H, s, Me), 3.85 (2H, t, J 6.7 Hz, CH2N), 4.69 (2H, br
t, CH2Nþ), 7.71e7.74 (1H, m, 7-H), 7.77e7.80 (1H, m, 8-H), 7.83e7.89
(4H, m, 40-H, 50-H, 60-H, 70-H), 8.17 (1H, d, J 9.1 Hz, 4-H), 8.20 (1H, d, J
7.9 Hz, 6-H), 8.28 (1H, d, J 9.1 Hz, 5-H), 8.36 (1H, d, J 8.5 Hz, 9-H); dC
(DMSO-d6) 13.70 (Me), 21.49 (CMe2), 26.36 (CH2CH2N), 34.76
(CH2N), 45.80 (CH2Nþ), 55.45 (1-C), 113.09 (4-C), 122.90 (50-C, 60-C),
123.26 (9-C), 127.10 and 127.17 (8-C, 9a-C), 128.31 (7-C), 129.59 (6-
C), 130.58 (5-C), 131.70 (3a0-C, 7a0-C), 132.93 (5a-C), 134.22 (40-C, 70-
C), 136.83 (9b-C), 138.35 (3a-C), 168.00 (10-C, 30-C), 196.88 (2-C).
Method B. Triethylamine (160
mL, 1 mmol) and then ethyl
orthoformate (130 L, 0.8 mmol) were added dropwise to a hot
m
mixture of salt 6c (496 mg, 1 mmol) and acetic anhydride (20 mL),
and the reaction mixture was stirred under reflux for 3 h. The pink
reaction mixture was poured into cold water (600 mL) and the
crude dye was filtered off and washed with water and cold EtOH.
The dye was dissolved in hot EtOH and filtered, and the filtrate was
diluted with diethyl ether (600 mL) and cooled to ꢂ10 ꢀC. The
precipitate that formed was filtered off and washed with diethyl
ether. Yield 9c: 284 mg (63%).
4.6. Synthesis of monomethine cyanine dyes 8a,b
A mixture of salts 1a,b (1 mmol) and 4a,c (1 mmol) was dis-
solved in abs EtOH (20 mL) at heating, and then triethylamine
(310 mL, 2.20 mmol) was added to this solution. The reaction mix-
4.7.1. 3-[3-(1,3-Dioxo-1,3-dihydro-2H-isoindol-2-yl)propyl]-2-
{(1E,3Z)-3-[3-[3-(1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)propyl]-
1,3-benzothiazol-2(3H)-ylidene]prop-1-en-1-yl}-1,3-benzothiazol-3-
ium perchlorate (9a). Dye 9a was isolated as purple crystals. Found
C, 59.64; H, 4.16; N, 6.98. C39H31ClN4O8S2 requires C, 59.80; H, 3.99;
ture was stirred under reflux for 5 h and then cooled to ꢂ10 ꢀC. The
precipitate that formed was filtered off and washed with cold EtOH
and diethyl ether and dried in air. Yield 8a: 442 mg (60%). In the
case of 8b, the tosylate salt of the dye was dissolved in abs EtOH
N, 7.15%. Mp 263e264 ꢀC; UVevis (MeCN) lmax 559 nm (
128,300 L molꢂ1 cmꢂ1); fluorescence (MeCN) lex 549 nm, lfmax
3
(15 mL) at heating and then HClO4 (70% (aq), 80 mL, 0.9 mmol) was
added to the solution. After cooling to ꢂ10 ꢀC, the precipitate that
formed was filtered off and washed with cold abs EtOH and diethyl
ether and dried in air. Yield 8b: 513 mg (61%).
584 nm. IR (KBr) 1709 (C]O) cmꢂ1
; dH (DMSO-d6) 2.10e2.16 (4H,
m, 2CH2CH2N), 3.77 (4H, t, J 7.1 Hz, 2CH2N), 4.41e4.46 (4H, m,
2CH2Nþ), 4.62 (4H, br t, 2CH2Nþ),6.56 (2H, d, J 12.7 Hz, 2ꢁ
a-H),
7.37e7.40 (2H, m, 2ꢁ6-H), 7.52e7.55 (2H, m, 2ꢁ5-H), 7.70e7.85
(11H, m, meso-H, 2ꢁ4-H, 2ꢁ40-H, 2ꢁ50-H, 2ꢁ60-H, 2ꢁ70-H), 7.96
(2H, d, J 7.9 Hz, 2ꢁ7-H); dC (DMSO-d6) 26.05 (2CH2CH2N), 35.03
4.6.1. 3-[3-(1,3-Dioxo-1,3-dihydro-2H-isoindol-2-yl)propyl]-2-{(Z)-
[3-[3-(1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)propyl]-1,3-
benzothiazol-2(3H)-ylidene]methyl}-1,3-benzothiazol-3-ium bromide
(8a). Dye 8a was isolated as yellow crystals. Found C, 59.02; H,
4.05; N, 7.48. C37H29BrN4O4S2$H2O requires C, 58.81; H, 4.14; N,
(2CH2N), 44.07 (2CH2Nþ), 98.70 (2
a-C), 113.44 (2ꢁ4-C), 122.87
(2ꢁ50-C, 2ꢁ60-C), 124.87 (2ꢁ7-C), 125.16 (2ꢁ6-C), 126.50 (2ꢁ7a-C),
127.98 (2ꢁ5-C), 131.68 (2ꢁ3a0-C, 2ꢁ7a0-C), 134.20 (2ꢁ40-C, 2ꢁ70-C),
140.95 (2ꢁ3a-C), 146.56 (meso-C), 164.65 (2ꢁ2-C), 167.92 (2ꢁ10-C,
2ꢁ30-C).
7.41%. Mp 281 ꢀC; UVevis (MeCN) lmax 425 nm
82,500 L molꢂ1 cmꢂ1); fluorescence (MeCN) lex 415 nm, lfmax
475 nm. IR (KBr) 1706 (C]O) cmꢂ1
dH (DMSO-d6) 2.16e2.23 (4H,
(
3
;
m, 2CH2CH2N), 3.77 (4H, br t, 2CH2N), 4.80 (4H, br t, 2CH2Nþ), 6.79
(1H, s, meso-H), 7.49e7.52 (2H, m, 2ꢁ6-H), 7.64e7.73 (10H, m, 2ꢁ5-
H, 2ꢁ40-H, 2ꢁ50-H, 2ꢁ60-H, 2ꢁ70-H), 7.97 (2H, d, J 8.7 Hz, 2ꢁ4-H),
8.23 (2H, d, J 8.3 Hz, 2ꢁ7-H); dC (DMSO-d6) 25.42 (2CH2CH2N),
34.80 (2CH2N), 43.82 (2CH2Nþ), 82.66 (meso-C), 113.70 (2ꢁ4-C),
122.66 (2ꢁ7-C, 2ꢁ50-C, 2ꢁ60-C), 123.52 (2ꢁ6-C), 124.83 (2ꢁ7a-C),
128.57 (2ꢁ5-C), 131.48 (2ꢁ3a0-C, 2ꢁ7a0-C), 134.08 (2ꢁ40-C, 2ꢁ70-C),
139.98 (2ꢁ3a-C), 161.78 (2ꢁ2-C), 167.75 (2ꢁ10-C, 2ꢁ30-C).
4.7.2. 1-[3-(1,3-Dioxo-1,3-dihydro-2H-isoindol-2-yl)propyl]-2-
((1E,3E)-3-{1-[3-(1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)propyl]-
3,3-dimethyl-1,3-dihydro-2H-indol-2-ylidene}prop-1-en-1-yl)-3,3-
dimethyl-3H-indolium perchlorate (9b). Dye 9b was isolated as
purple crystals. Found C, 67.15; H, 5.45; N, 6.81. C45H43ClN4O8 re-
quires C, 67.28; H, 5.40; N, 6.98%. Mp 263e264 ꢀC; UVevis (MeCN)
lmax 548 nm (
3
130,300 L molꢂ1 cmꢂ1); fluorescence (MeCN) lex
dH (DMSO-d6) 1.72
538 nm, lfmax 572 nm. IR (KBr) 1714 (C]O) cmꢂ1
;
(12H, s, 2CMe2), 2.10e2.15 (4H, m, 2CH2CH2N), 3.72 (4H, t, J 7.1 Hz,
4.6.2. 3-[6-(1,3-Dioxo-1,3-dihydro-2H-isoindol-2-yl)hexyl]-2-{(Z)-
[3-[6-(1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)hexyl]-1,3-
benzothiazol-2(3H)-ylidene]methyl}-1,3-benzothiazol-3-ium
2CH2N), 4.25 (4H, br t, 2CH2Nþ), 6.49 (2H, d, J 13.5 Hz, 2ꢁ
a-H), 7.30
(2H, t, J 7.3 Hz, 2ꢁ5-H), 7.43 (2H, t, J 8.0 Hz, 2ꢁ6-H), 7.51 (2H, d, J
8.0 Hz, 2ꢁ7-H), 7.64 (2H, d, J 7.3 Hz, 2ꢁ4-H), 7.79e7.83 (8H, m,

5904
S.P. Gromov et al. / Tetrahedron 69 (2013) 5898e5907
2ꢁ40-H, 2ꢁ50-H, 2ꢁ60-H, 2ꢁ70-H), 8.37 (1H, t, J 13.5 Hz, meso-H); dC
(DMSO-d6) 25.92 (2CH2CH2N), 27.32 (2CMe2), 35.03 (2CH2N), 41.52
ium perchlorate (11a). Dye 11a was isolated as a blue solid. Found C,
61.79; H, 4.38; N, 6.59. C43H37ClN4O8S2 requires C, 61.68; H, 4.45; N,
(2CH2Nþ), 48.90 (2ꢁ3-C), 102.70 (2ꢁ
a
-C), 111.48 (2ꢁ7-C), 122.45
6.69%. Mp 220 ꢀC; UVevis (MeCN) lmax 655 nm
(
3
(2ꢁ4-C), 122.86 (2ꢁ50-C, 2ꢁ60-C), 125.24 (2ꢁ5-C), 128.56 (2ꢁ6-C),
131.63 (2ꢁ3a0-C, 2ꢁ7a0-C), 134.19 (2ꢁ40-C, 2ꢁ70-C), 140.49 (2ꢁ3a-
C), 141.69 (2ꢁ7a-C), 149.90 (meso-C), 167.85 (2ꢁ10-C, 2ꢁ30-C),
173.97 (2ꢁ2-C).
177,000 L molꢂ1 cmꢂ1); fluorescence (MeCN) lex 645 nm, lfmax
685 nm. IR (KBr) 1710 (C]O) cmꢂ1
dH (DMSO-d6) 1.73e1.78 (8H, m,
2CH2CH2), 3.63e3.65 (4H, m, 2CH2N), 4.33e4.35 (4H, m, 2CH2Nþ),
6.42 (1H, br t, meso-H), 6.50 (2H, d, J 13.1 Hz, 2ꢁ -H), 7.34e7.37 (2H,
;
a
m, 2ꢁ6-H), 7.49e7.52 (2H, m, 2ꢁ5-H), 7.63e7.72 (4H, m, 2ꢁ4-H,
4.7.3. 3-[3-(1,3-Dioxo-1,3-dihydro-2H-isoindol-2-yl)propyl]-2-((1E,
3E)-3-{3-[3-(1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)propyl]-1,1-
dimethyl-1,3-dihydro-2H-benzo[e]indol-2-ylidene}prop-1-en-1-yl)-
1,1-dimethyl-1H-benzo[e]indolium perchlorate (9c). Dye 9c was
isolated as dark purple crystals. Found C, 69.21; H, 5.25; N, 5.73.
C53H47ClN4O8$H2O requires C, 69.08; H, 5.36; N, 6.08%. Mp 230 ꢀC;
2ꢁ
b
-H), 7.81e7.86 (8H, m, 2ꢁ40-H, 2ꢁ50-H, 2ꢁ60-H, 2ꢁ70-H),
7.94e7.95 (2H, m, 2ꢁ7-H); dC (DMSO-d6) 22.56 and 24.95
(4CH2CH2), 36.88 (2CH2N), 45.48 (2CH2Nþ), 100.28 (2ꢁ
a-C), 113.23
(2ꢁ4-C), 122.86 (meso-C), 122.93 (2ꢁ7-C), 124.83 (2ꢁ50-C, 2ꢁ60-C),
125.15 (2ꢁ6-C), 127.85 (2ꢁ7a-C, 2ꢁ5-C), 131.45 (2ꢁ3a0-C, 2ꢁ7a0-C),
134.29 (2ꢁ40-C, 2ꢁ70-C), 141.19 (2ꢁ3a-C), 150.25 (2ꢁ
b-C), 163.42
UVevis (MeCN) lmax 588 nm (
3
96,900 L molꢂ1 cmꢂ1); fluorescence
dH
(2ꢁ2-C), 167.96 (2ꢁ10-C, 2ꢁ30-C).
(MeCN) lex 578 nm, lmf ax 612 nm. IR (KBr) 1710 (C]O) cmꢂ1
;
(DMSO-d6) 2.03 (12H, s, 2CMe2), 2.17e2.23 (4H, m, 2CH2CH2N), 3.76
4.9.2. 1-[3-(1,3-Dioxo-1,3-dihydro-2H-isoindol-2-yl)propyl]-2-
((1E,3E,5E)-5-{1-[3-(1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)propyl]-
3,3-dimethyl-1,3-dihydro-2H-indol-2-ylidene}penta-1,3-dien-1-yl)-
3,3-dimethyl-3H-indolium perchlorate (11b). Dye 11b was isolated as
a blue solid. Found C, 65.75; H, 5.32; N, 6.86. C47H45ClN4O8$1.5H2O
requires C, 65.92; H, 5.65; N, 6.54%. Mp 163e165 ꢀC; UVevis (MeCN)
(4H, br t, 2CH2N), 4.40 (4H, br t, 2CH2Nþ), 6.55 (2H, d, J 13.3 Hz,
2ꢁ -H), 7.53e7.56 (2H, m, 2ꢁ7-H), 7.68e7.71 (2H, m, 2ꢁ8-H),
a
7.77e7.84 (10H, m, 2ꢁ4-H, 2ꢁ40-H, 2ꢁ50-H, 2ꢁ60-H, 2ꢁ70-H), 8.07
(2H, d, J 8.3 Hz, 2ꢁ6-H), 8.10 (2H, d, J 8.7 Hz, 2ꢁ5-H), 8.30 (2H, d, J
8.3 Hz, 2ꢁ9-H), 8.59 (1H, t, J 13.3 Hz, meso-H); dC (DMSO-d6) 26.18
(2CH2CH2N), 26.99 (2CMe2), 35.05 (2CH2N), 41.71 (2CH2Nþ), 50.59
lmax 643 nm (
3
166,400 L molꢂ1 cmꢂ1); fluorescence (MeCN) lex
dH (DMSO-d6) 1.69
(2ꢁ1-C), 102.23 (2ꢁ
a
-C), 111.63 (2ꢁ4-C), 122.08 (2ꢁ9-C), 122.87
633 nm, lfmax 671 nm. IR (KBr) 1709 (C]O) cmꢂ1
;
(2ꢁ50-C, 2ꢁ60-C), 125.04 (2ꢁ7-C), 127.27 (2ꢁ9a-C), 127.85 (2ꢁ8-C),
129.86 (2ꢁ6-C), 130.42 (2ꢁ5-C), 131.44 (2ꢁ5a-C), 131.65 (2ꢁ3a0-C,
2ꢁ7a0-C), 133.03 (2ꢁ9b-C), 134.17 (2ꢁ40-C, 2ꢁ70-C), 139.39 (2ꢁ3a-
C), 148.46 (meso-C), 167.90 (2ꢁ10-C, 2ꢁ30-C), 175.22 (2-C).
(12H, s, 2CMe2), 2.03e2.09 (4H, m, 2CH2CH2N), 3.71 (4H, brt, 2CH2N),
4.22e4.25 (4H, m, 2CH2Nþ), 6.28 (2H, d, J 13.8 Hz, 2ꢁ
a-H), 6.38 (1H, t,
J 12.3 Hz, meso-H), 7.23e7.26 (2H, m, 2ꢁ5-H), 7.37e7.40 (2H, m, 2ꢁ7-
H), 7.44e7.46 (2H, m, 2ꢁ6-H), 7.62 (2H, d, J 7.3 Hz, 2ꢁ4-H), 7.82e7.86
(8H, m, 2ꢁ40-H, 2ꢁ50-H, 2ꢁ60-H, 2ꢁ70-H), 8.30e8.35 (2H, m, 2ꢁ
b-H);
4.8. Synthesis of 2-amino-1-methylpyrimidin-1-ium per-
chlorate (10)
dC (DMSO-d6) 25.95 (2CH2CH2N), 26.98 (2CMe2), 34.97 (2CH2N),
41.10 (2CH2Nþ), 48.87 (2ꢁ3-C), 103.17 (2ꢁ
-C), 110.97 (2ꢁ7-C),
a
122.37 (2ꢁ4-C), 122.91 (2ꢁ50-C, 2ꢁ60-C), 124.68 (meso-C), 125.44
(2ꢁ5-C), 128.33 (2ꢁ6-C), 131.66 (2ꢁ3a0-C, 2ꢁ7a0-C), 134.21 (2ꢁ40-C,
Perchloric acid (70%, aq) (0.1 mL, 1.1 mmol) was added to a so-
lution of 2-amino-1-methylpyrimidin-1-ium iodide (237 mg,
1 mmol) in MeOH (2 mL). The reaction mixturewas heated and, after
cooling to 5 ꢀC, the precipitate that formed was filtered off and
washed with MeOH to yield 10 (0.161 mg, 76%) as a white powder.
Found C, 28.48; H, 3.72; N, 19.88. C5H8ClN3O4 requires C, 28.65; H,
3.85; N, 20.05%. Mp 190e193 ꢀC (decomp.). IR (KBr) 3344, 3289
2ꢁ70-C), 140.96 (2ꢁ3a-C), 141.85 (2ꢁ7a-C), 154.16 (2ꢁ
b-C), 167.86
(2ꢁ10-C, 2ꢁ30-C), 172.70 (2ꢁ2-C).
4.9.3. 1-[4-(1,3-Dioxo-1,3-dihydro-2H-isoindol-2-yl)butyl]-2-
((1E,3E,5E)-5-{1-[4-(1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)butyl]-
3,3-dimethyl-1,3-dihydro-2H-indol-2-ylidene}penta-1,3-dien-1-yl)-
3,3-dimethyl-3H-indolium perchlorate (11c). Dye 11c was isolated as
a blue solid. Found C, 65.55; H, 5.65; N, 6.95. C49H49ClN4O8$2H2O
requires C, 65.87; H, 5.98; N, 6.27%. Mp 125e130 ꢀC; UVevis
(NH2) cmꢂ1
; dH (DMSO-d6) 3.71 (3H, s, Me), 7.06e7.09 (1H, m, 5-H),
8.53e8.54 (1H, m, 4-H), 8.82e8.83 (1H, m, 6-H), 9.30 (2H, br s, NH2).
4.9. Synthesis of pentamethine cyanine dyes 11aec
(MeCN) lmax 643 nm (
3
168,500 L molꢂ1 cmꢂ1); fluorescence
dH
(MeCN) lex 633 nm, lmf ax 671 nm. IR (KBr) 1709 (C]O) cmꢂ1
;
Method A. Triethylamine (139
m
L, 1 mmol) was added to a hot
(DMSO-d6) 1.66 (12H, s, 2CMe2), 1.71e1.76 (8H, m, 2CH2CH2),
mixture of salts 4e (451 mg, 1 mmol) and 10 (105 mg, 0.5 mmol) in
pyridine (20 mL) and the reaction mixture was stirred under reflux
for 4 h. Pyridine was evaporated in vacuo and the residue was
washed with EtOH and hot benzene and dissolved in acetone
(10 mL). The solution was filtered, the filtrate was concentrated in
vacuo toavolume of w2 mL. The precipitate that formed was filtered
off and washed with a mixture of EtOH (20 mL) and water (20 mL),
then with diethyl ether, and dried in air. Yield 11a: 126 mg (30%).
3.61e3.64 (4H, m, 2CH2N), 4.11e4.16 (4H, m, 2CH2Nþ), 6.28 (2H, d, J
13.1 Hz, 2ꢁ
a-H), 6.51 (1H, t, J 12.2 Hz, meso-H), 7.21e7.24 (2H, m,
2ꢁ5-H), 7.36e7.42 (4H, m, 2ꢁ6-H, 2ꢁ7-H), 7.60 (2H, m, 2ꢁ4-H),
7.79e7.85 (8H, m, 2ꢁ40-H, 2ꢁ50-H, 2ꢁ60-H, 2ꢁ70-H), 8.25 (2H, m,
2ꢁ
b-H); dC (DMSO-d6) 24.08 and 24.98 (2CH2CH2), 27.01 (2CMe2),
36.90 (2CH2N), 42.81 (2CH2Nþ), 48.76 (2ꢁ3-C), 103.12 (2ꢁ
a-C),
110.98 (2ꢁ7-C), 122.29 (2ꢁ4-C), 122.91 (2ꢁ50-C, 2ꢁ60-C), 124.57
(meso-C), 125.40 (2ꢁ5-C), 128.29 (2ꢁ6-C), 131.41 (2ꢁ3a0-C, 2ꢁ7a0-
C), 134.27 (2ꢁ40-C, 2ꢁ70-C), 140.95 (2ꢁ3a-C), 141.90 (2ꢁ7a-C),
Method B. Triethylamine (139 mL, 1 mmol) was added to a mix-
ture of salts 6a,b (1 mmol) and 10 (140 mg, 0.65 mmol) in acetic
anhydride (5 mL). The reaction mixture was stirred under reflux for
2 h and then poured into water (600 mL). The precipitate that
formed was filtered off and washed with water. The crude dye was
dissolved in acetone (w2 mL) and poured into diethyl ether
(300 mL). The precipitate that formed was filtered off, washed with
diethyl ether and dried in air. Yield 11b: 205 mg (48%). Yield 11c:
299 mg (70%).
153.99 (2ꢁ
b
-C), 167.93 (2ꢁ10-C, 2ꢁ30-C), 172.56 (2ꢁ2-C).
4.10. Deprotection of phthalimide group to yield dyes 12aef
Method A. A mixture of dye 8b, 9b,c, 11b,c (1 mmol) and a 38%
solution of MeNH2 in abs EtOH (80 mL) was stirred at room tem-
perature for 2 h and then kept overnight at 5 ꢀC. The solvent was
evaporated in vacuo, the residue was washed with hot EtOAc and
dissolved in EtOH and then HClO4 (70% (aq), 260 mL, 3 mmol) was
4.9.1. 3-[4-(1,3-Dioxo-1,3-dihydro-2H-isoindol-2-yl)butyl]-2-{(1E,3E,
5Z)-5-[3-[4-(1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)butyl]-1,3-
benzothiazol-2(3H)-ylidene]penta-1,3-dien-1-yl}-1,3-benzothiazol-3-
added to this solution. After cooling to ꢂ10 ꢀC, the crystalline
precipitate was filtered off, washed with EtOAc and diethyl ether
and dried in air. Yield 12a: 344 mg (44%). Yield 12c: 300 mg (40%).

S.P. Gromov et al. / Tetrahedron 69 (2013) 5898e5907
5905
Yield 12d: 201 mg (25%). Yield 12e: 323 mg (42%). Yield 12f:
407 mg (51%).
C37H45Cl3N4O12$H2O requires C, 51.55; H, 5.50; N, 6.50%. Mp
274e275 ꢀC; UVevis (MeCN) lmax 587 nm ( 90,100 L molꢂ1 cmꢂ1);
3
Method B. Hydrazine monohydrate (1.00 mL, 20 mmol) was added
to a stirred solution of dye 9a,b, 11c (1 mmol) in a mixture of CH2Cl2
(100 mL) and MeOH (40 mL). The reaction mixture was stirred under
reflux for 3e6 h and cooled to room temperature. The precipitate of
2,3-dihydrophthalazine-1,4-dione that formed was filtered off,
washed with hot benzene and EtOH. The filtrate was evaporated in
vacuo, the residue was dissolved in DMSO (10 mL) (in the case of 12b)
fluorescence (MeCN) lex 577 nm, lfmax 611 nm; dH (DMSO-d6) 2.07
(12H, s, 2CMe2), 2.12e2.18 (4H, m, 2CH2CH2NHþ3 ), 2.99e3.08 (4H,
m, 2CH2NHþ3 ), 4.36e4.38 (4H, m, 2CH2Nþ), 6.57 (2H, d, J 13.3 Hz,
2ꢁ -H), 7.56e7.59 (2H, m, 2ꢁ7-H), 7.71e7.74 (8H, m, 2ꢁ8-H,
a
2NHþ3 ), 7.83 (2H, d, J 9.0 Hz, 2ꢁ4-H), 8.11 (2H, d, J 8.0 Hz, 2ꢁ6-H),
8.16 (2H, d, J 9.0 Hz, 2ꢁ5-H), 8.31 (2H, d, J 8.0 Hz, 2ꢁ9-H), 8.66 (1H,
br t, meso-H); dC (DMSO-d6) 26.16 (2CH2CH2NHþ3 ), 26.89 (2CMe2),
or EtOH (10 mL) (in the case of 12c,f), and HClO4 (70% (aq), 260
mL,
36.28 (2CH2NHþ), 41.02 (2CH2Nþ), 50.42 (2ꢁ1-C), 101.61 (2ꢁ
a-C),
3 mmol) was added to this solution. The resulting mixture was di-
luted with water (200 mL) and the precipitate that formed was fil-
tered off and washed with water, a mixture of EtOH (20 mL) and
water (20 mL), then with diethyl ether, and dried in air. Yield 12b:
89 mg (17%). Yield 12c: 335 mg (45%). Yield 12f: 295 mg (37%).
111.11 (2ꢁ4-C), 3121.76 (2ꢁ9-C), 124.87 (2ꢁ7-C), 127.09 (2ꢁ9a-C),
127.62 (2ꢁ8-C), 129.58 (2ꢁ6-C), 130.14 (2ꢁ5-C), 131.34 (2ꢁ5a-C),
133.06 (2ꢁ9b-C), 138.94 (2ꢁ3a-C), 148.71 (meso-C), 175.50 (2ꢁ2-C).
4.10.5. 1-(3-Ammoniopropyl)-2-{(1E,3E,5E)-5-[1-(3-ammoniopropyl)-
3,3-dimethyl-1,3-dihydro-2H-indol-2-ylidene]penta-1,3-dien-1-yl}-
3,3-dimethyl-3H-indolium triperchlorate (12e). Dye 12e was isolated
as a blue solid. Found C, 47.07; H, 5.47; N, 7.38. C31H43Cl3N4O12$H2O
requires C, 47.25; H, 5.76; N, 7.11%. Mp 196e198 ꢀC; UVevis (MeCN)
4.10.1. 3-(6-Ammoniohexyl)-2-{(Z)-[3-(6-ammoniohexyl)-1,3-
benzothiazol-2(3H)-ylidene]methyl}-1,3-benzothiazol-3-ium triper-
chlorate (12a). Dye 12a was isolated as a yellow solid. Found C,
41.54; H, 5.09; N, 6.98. C27H39Cl3N4O12S2 requires C, 41.46; H, 5.03;
lmax 640 nm (
141,000 L molꢂ1 cmꢂ1); fluorescence (MeCN) lex
3
N, 7.16%. Mp 142e143 ꢀC; UVevis (MeCN) lmax 426 nm (
3
630 nm, lfmax 667 nm; dH (DMSO-d6) 1.70 (12H, s, 2CMe2), 1.95e2.01
lfmax
66,500 L molꢂ1 cmꢂ1); fluorescence (MeCN) lex 416 nm,
(4H, m, 2CH2CH2NHþ3 ), 2.88e2.96 (4H, m, 2CH2NHþ3 ), 4.19e4.22 (4H,
477 nm; dH (DMSO-d6) 1.32e1.38, 1.41e1.46, 1.47e1.52 and
1.57e1.81 (16H, 4m, 8CH2), 2.71e2.77 (4H, m, 2CH2NHþ3 ), 4.65 (4H,
br t, 2CH2Nþ), 6.68 (1H, s, meso-H), 7.51e7.54 (2H, m, 2ꢁ6-H), 7.57
(6H, br s, 2NHþ3 ), 7.69e7.72 (2H, m, 2ꢁ5-H), 7.91 (2H, d, J 8.5 Hz,
2ꢁ4-H), 8.25 (2H, d, J 7.9 Hz, 2ꢁ7-H); dC (DMSO-d6) 25.37, 25.43,
26.65 and 26.74 (8CH2), 38.64 (2CH2NHþ3 ), 45.97 (2CH2Nþ), 82.39
(meso-C), 113.73 (2ꢁ4-C), 123.53 (2ꢁ7-C), 124.81 (2ꢁ6-C), 124.97
(2ꢁ7a-C), 128.54 (2ꢁ5-C), 140.13 (2ꢁ3a-C), 161.63 (2ꢁ2-C).
m, 2CH2Nþ), 6.33 (2H, d, J 13.4 Hz, 2ꢁ
a-H), 6.54e6.56 (1H, m, meso-
H), 7.27e7.31 (2H, m, 2ꢁ5-H), 7.40e7.43 (4H, m, 2ꢁ6-H, 2ꢁ7-H),
7.59e7.72 (8H, m, 2NHþ3 , 2ꢁ4-H), 8.36e8.41 (2H, m, 2ꢁ
b-H); dC
(DMSO-d6) 25.09 (2CH2CH2NHþ3 ), 27.22 (2CMe2), 36.84 (2CH2NHþ),
42.86 (2CH2Nþ), 48.90 (2ꢁ3-C), 103.06 (2ꢁ
a
-C), 111.05 (2ꢁ7-3C),
122.67 (2ꢁ4-C), 124.70 (2ꢁ5-C), 125.40 (meso-C), 128.26 (2ꢁ6-C),
140.96 (2ꢁ3a-C), 141.83 (2ꢁ7a-C), 154.13 (2ꢁ -C), 172.77 (2ꢁ2-C).
b
4.10.6. 1-(4-Ammoniobutyl)-2-{(1E,3E,5E)-5-[1-(4-ammoniobutyl)-
3,3-dimethyl-1,3-dihydro-2H-indol-2-ylidene]penta-1,3-dien-1-yl}-
3,3-dimethyl-3H-indolium triperchlorate (12f). Dye 12f was isolated
as a blue solid. Found C, 48.61; H, 5.71; N, 7.08. C33H47Cl3N4O12$H2O
requires C, 48.57; H, 6.05; N, 6.87%. Mp >180 ꢀC; UVevis (MeCN)
4.10.2. 3-(3-Ammoniopropyl)-2-{(1E,3Z)-3-[3-(3-ammoniopropyl)-
1,3-benzothiazol-2(3H)-ylidene]prop-1-en-1-yl}-1,3-benzothiazol-3-
ium triperchlorate (12b). Dye 12b was isolated as violet crystals.
Found C, 35.25; H, 3.68; N, 6.67. C23H29Cl3N4O12S2$0.5H-
ClO4$0.5DMSO requires C, 35.44; H, 4.03; N, 6.89%. Mp 230e231 ꢀC;
lmax 641 nm (
123,800 L molꢂ1 cmꢂ1); fluorescence (MeCN) lex
3
UVevis (MeCN) lmax 558 nm (
3
78,000 L molꢂ1 cmꢂ1); fluorescence
631 nm, lfmax 668 nm; dH (DMSO-d6) 1.70 (12H, s, 2CMe2),1.58e1.64
(MeCN) lex 548 nm, lfmax 580 nm; dH (DMSO-d6) 2.01e2.08 (4H, m,
and 1.73e1.77 (8H, 2m, 2CH2CH2), 2.81e2.86 (4H, m, 2CH2NHþ3 ),
2CH2CH2NHþ3 ), 2.94e3.00 (4H, m, 2CH2NHþ), 4.39e4.44 (4H, m,
4.14e4.17 (4H, m, 2CH2Nþ), 6.30 (2H, d, J 14.0 Hz, 2ꢁ
a-H), 6.54 (1H,
2CH2Nþ), 6.57 (2H, br d, 2ꢁ
a
-H), 7.45e7.483(2H, m, 2ꢁ6-H), 7.62
t, J 12.2 Hz, meso-H), 7.25e7.28 (2H, m, 2ꢁ5-H), 7.41e7.44 (4H, m,
(2H, m, 2ꢁ5-H), 7.72 (6H, br s, 2NHþ2 ), 7.81e7.88 (3H, m, meso-H,
2ꢁ6-H, 2ꢁ7-H), 7.60 (6H, br s, 2NHþ3 ), 7.63e7.64 (2H, m, 2ꢁ4-H),
2ꢁ4-H), 8.03e8.04 (2H, m, 2ꢁ7-H); dC (DMSO-d6) 25.34
8.33e8.38 (2H, m, 2ꢁ
b-H); dC (DMSO-d6) 24.02 and 24.23
(2CH2CH2NHþ3 ), 36.22 (2CH2NHþ), 43.34 (2CH2Nþ), 98.50 (2ꢁ
a
-C),
(2CH2CH2), 27.05 (2CMe2), 38.51 (2CH2NHþ3 ), 42.73 (2CH2Nþ),
48.85 (2ꢁ3-C), 103.08 (2ꢁ -C), 111.07 (2ꢁ7-C), 122.39 (2ꢁ4-C),
124.71 (2ꢁ5-C), 125.39 (meso-C), 128.31 (2ꢁ6-C), 141.00 (2ꢁ3a-C),
141.89 (2ꢁ7a-C), 154.10 (2ꢁ -C), 172.79 (2ꢁ2-C).
113.33 (2ꢁ4-C), 123.11 (2ꢁ7-C),3125.01 (2ꢁ7a-C), 125.35 (2ꢁ6-C),
128.02 (2ꢁ5-C), 141.06 (2ꢁ3a-C), 146.76 (meso-C), 164.94 (2ꢁ2-C).
a
b
4.10.3. 1-(3-Ammoniopropyl)-2-{(1E,3E)-3-[1-(3-ammoniopropyl)-
3,3-dimethyl-1,3-dihydro-2H-indol-2-ylidene]prop-1-en-1-yl}-3,3-
dimethyl-3H-indolium triperchlorate (12c). Dye 12c was isolated as
violet crystals. Found C, 44.76; H, 5.79; N, 7.14. C29H41Cl3N4O12$2H2O
requires C, 44.65; H, 5.82; N, 7.18%. Mp 261e265 ꢀC; UVevis (MeCN)
4.11. X-ray diffraction study
The crystals of dyes 8b and 9a,b were grown using a slow
evaporation of a solution of dye in a CHCl3eCH2Cl2eMeCN mixture
at ambient temperature. The single crystals were coated with per-
lmax 546 nm (
106,800 L molꢂ1 cmꢂ1); fluorescence (MeCN) lex
3
536 nm, lfmax 569 nm; dH (DMSO-d6) 1.73 (12H, s, H, s, 2CMe2),
fluorinated oil and mounted on a Bruker SMART-CCD diffractometer
2.02e2.07 (4H, m, 2CH2CH2NHþ3 ), 2.94e2.97 (4H, m, 2CH2NHþ3 ),
(graphite monochromatized Mo K
a
radiation (
l
¼0.71073 A),
u scan
ꢀ
4.21 (4H, br t, 2CH2Nþ), 6.50 (2H, d, J 13.6 Hz, 2ꢁ
a
-H), 7.33e7.36 (2H,
mode) under a stream of cooled nitrogen (T¼120.0(2) K for 9a,b and
150(2) K for 8b). The sets of experimental reflections were measured
and the structures were solved by direct methods and refined by the
full matrix least-squares against F2 with anisotropic thermal pa-
rameters for all non-hydrogen atoms (except for the oxygen atoms
of the disordered perchlorate anions in 8b and 9b). The hydrogen
atoms were fixed at calculated positions of the carbon atoms and
then refined using a riding model. Four water solvate molecules
disordered near a symmetry center of the crystal were found in
structure 8b$1.75H2O; their occupancies are 0.75, 0.50, 0.25, and
0.25. The ISOR command was applied to make better the anisotropic
parameters of these oxygen atoms. The hydrogen atoms of the water
m, 2ꢁ5-H), 7.47e7.50 (2H, m, 2ꢁ6-H), 7.53 (2H, d, J 8.0 Hz, 2ꢁ7-H),
7.67e7.72 (8H, m, 2ꢁ4-H, 2NH3þ), 8.40 (1H, t, J 13.6 Hz, meso-H); dC
(DMSO-d6) 25.12 (2CH2CH2NHþ3 ), 27.32 (2CMe2), 36.38 (2CH2NHþ3 ),
41.96 (2CH2Nþ), 48.92 (2ꢁ3-C), 102.33 (2ꢁ
-C), 111.31 (2ꢁ7-C),
a
122.52 (2ꢁ4-C), 125.35 (2ꢁ5-C), 128.51 (2ꢁ6-C), 140.51 (2ꢁ3a-C),
141.62 (2ꢁ7a-C), 150.15 (meso-C), 174.23 (2ꢁ2-C).
4.10.4. 3-(3-Ammoniopropyl)-2-{(1E,3E)-3-[3-(3-ammoniopropyl)-
1,1-dimethyl-1,3-dihydro-2H-benzo[e]indol-2-ylidene]prop-1-en-1-
yl}-1,1-dimethyl-1H-benzo[e]indolium triperchlorate (12d). Dye 12d
was isolated as a violet solid. Found C, 51.66; H, 5.53; N, 6.24.

5906
S.P. Gromov et al. / Tetrahedron 69 (2013) 5898e5907
Table 2
Crystallographic data and structure refinement details for 8b$1.75H2O, 9a$0.6CH2Cl2$0.4CHCl3 and 9b$2MeCN
Parameter
8b$1.75H2O
43H44.5ClN4O9.75S2
872.90
Monoclinic
C2/c
9a$0.6CH2Cl2$0.4CHCl3
9b$2MeCN
Empirical formula
Formula weight
Crystal system
Space group
C
C40H32.6Cl3.4N4O8S2
881.95
Triclinic
P1
C49H49ClN6O8
885.39
Triclinic
P1
ꢀ
Unit cell: dimensions (A),
a¼20.486(3), b¼18.008(3),
a¼9.5883(11), b¼14.3371(17),
a¼11.7498(3), b¼14.0094(4),
c¼22.511(3)
c¼14.9796(18)
c¼14.6629(4)
Angle (ꢀ)
b¼96.954(2)
a
¼69.794(5),
¼89.958(5)
b
¼87.688(5),
a
¼107.330(1),
¼103.545(1)
b
¼96.328(1),
g
g
3
ꢀ
Volume (A )
8243(2)
8, 1.407
0.258
1930.7(4)
2, 1.517
0.434
2197.44(10)
2, 1.338
0.150
Z, Dcalcd [Mg/m3]
m
[mmꢂ1
]
F(000)
Crystal size (mm3)
Range (ꢀ)
3660
909
932
0.12ꢁ0.10ꢁ0.08
0.48ꢁ0.42ꢁ0.38
0.42ꢁ0.28ꢁ0.16
q
1.51e29.00
1.45e25.00
1.48e29.00
Index ranges
Reflections collected
Independent reflections
ꢂ27ꢃhꢃ27, ꢂ24ꢃkꢃ24, ꢂ30ꢃlꢃ30
43,139
ꢂ11ꢃhꢃ11, ꢂ14ꢃkꢃ17, ꢂ16ꢃlꢃ17
11,369
ꢂ15ꢃhꢃ16, ꢂ19ꢃkꢃ19, ꢂ19ꢃlꢃ19
23,403
10,909 [R(int)¼0.0883]
6595 [R(int)¼0.0535]
11,519 [R(int)¼0.0476]
Reflections with I>2
s
(I)
4922
5536
6796
Goodness-of-fit on F2
0.991
1.145
0.999
Final R indices [I>2
R indices (all data)
Largest diff. peak and hole (e A
s
(I)]
R1¼0.0828, wR2¼0.2133
R1¼0.1831, wR2¼0.2647
0.740 and ꢂ0.570
R1¼0.2362, wR2¼0.5266
R1¼0.2504, wR2¼0.5304
1.755 and ꢂ1.345
R1¼0.0680, wR2¼0.1872
R1¼0.1151, wR2¼0.2044
0.596 and ꢂ0.589
ꢀꢂ3
ꢂ
)
the Photographic Process, 4th ed.; Macmillan: New York, NY, 1977; pp 1e715; (e)
Mishra, A.; Behera, R. K.; Behera, P. K.; Mishra, B. K.; Behera, G. B. Chem. Rev.
2000, 100, 1973e2011.
2. (a) Era, M.; Adachi, C.; Tsutsui, T.; Saito, S. Chem. Phys. Lett. 1991, 178, 488e490;
(b) Ehret, A.; Stuhl, L.; Spitler, M. T. J. Phys. Chem. B 2001, 105, 9960e9965; (c)
Ooyama, Y.; Harima, Y. Eur. J. Org. Chem. 2009, 18, 2903e2934.
molecules were not located. The perchlorate anion in this structure
is strongly disordered over four positions (rotation about the center
of gravity of the anion) with a 0.40:0.30:0.20:0.10 occupancy ratio.
The SADI command was applied to constrain the geometry of this
anion. In the crystal of 9a, CH2Cl2 and CHCl3 solvate molecules were
found, which occupy the same position in the unit cell in a 0.60:0.40
ratio. The SADI and ISOR commands were applied in order to con-
strain the solvate molecules and anisotropic parameters of some
non-hydrogen atoms in structure 9a$0.6CH2Cl2$0.4CHCl3. Disor-
dered structure units have a rather large contribution to structure
factors of 8b and 9b. Since their positions were determined with
a low accuracy, this resulted in a rather low accuracy of these
structures as a whole. Nevertheless, the determination of the gen-
eral structure of the main molecules and relative positions of all
structure units in the crystal unit cells does not cast doubt. Two
MeCN solvate molecules were found in the crystal of 9b. The per-
chlorate anion in this structure is disordered over three positions
with a 0.60:0.30:0.10 occupancy ratio. The SADI command was ap-
plied to constrain the geometry of this anion. All the calculations
were performed using the SHELXTL-Plus software.21 The crystal
parameters and structure refinement details are given in Table 2.
Crystallographic data (excluding structure factors) for the structures
have been deposited with the Cambridge Crystallographic Data
Centre as supplementary publication nos. CCDC-933535
(8b$1.75H2O), CCDC-907649 (9a$0.6CH2Cl2$0.4CHCl3) and CCDC-
907650 (9b$2MeCN). Copies of the data can be obtained, free of
charge, on application to CCDC, 12 Union Road, Cambridge CB2 1EZ,
UK (fax: þ44 (0)1223 336033 or e-mail: deposit@ccdc.cam.ac.uk).
3. (a) Strekowski, L.; Lipowska, M.; Patonay, G. J. Org. Chem. 1992, 57, 4578e4580;
(b) Soper, S. A.; Mattingly, Q. L. J. Am. Chem. Soc. 1994, 116, 3744e3752; (c)
Armitage, B. A. In Topics in Current Chemistry; Waring, M. J., Chaires, J. B., Eds.;
Springer: Berlin, Heidelberg, Germany, 2005; Vol. 253, pp 55e76; (d) Armitage,
B. A.; Chen, Y.; Dobhal, M. P.; Henary, M.; James, N.; Je˛drzejewska, B.; Kabatc, J.;
Kim, J.; Mojzych, M.; Nakazumi, H.; Pa˛czkowski, J.; Pandey, R. K.; Patonay, G.;
Shirinian, V. Z.; Shimkin, A. A.; Traven, V. F.; Watson, A.; Yagi, S. In Topics in
Heterocyclic Chemistry; Strekowski, L., Ed.; Springer: Berlin, Heidelberg, Ger-
many, 2008; Vol. 14, pp 1e241; (e) Goncalves, M. S. T. Chem. Rev. 2009, 109,
190e212; (f) Tatikolov, A. S. J. Photochem. Photobiol., C 2012, 13, 55e90.
4. Fabian, J.; Nakazumi, H.; Matsuoka, M. Chem. Rev. 1992, 92, 1197e1226.
5. (a) Nau, W. M.; Mohanty, J. Int. J. Photoenergy 2005, 7, 133e141; (b) Koner, A. L.;
Nau, W. M. Supramol. Chem. 2007, 19, 55e66; (c) Gadde, S.; Batchelor, E. K.;
Kaifer, A. E. Chem.dEur. J. 2009, 15, 6025e6031; (d) Barros, T. C.; Toma, S. H.;
Toma, H. E.; Bastos, E. L.; Baptista, M. S. J. Phys. Org. Chem. 2010, 23, 893e903;
€
€
(e) Wurthner, F.; Kaiser, T. E.; Saha-Moller, Ch. R. Angew. Chem., Int. Ed. 2011, 50,
3376e3410.
6. (a) Kirstein, S.; Daehne, S. Int. J. Photoenergy 2006, 2006,1e21; (b) Slavnova, T. D.;
€
Gorner, H.; Chibisov, A. K. J. Phys. Chem. B 2007, 111, 10023e10031.
7. (a) Prins, L.; Reinhoudt, D.; Timmerman, P. Angew. Chem., Int. Ed. 2001, 40,
2382e2426; (b) Steiner, T. Angew. Chem., Int. Ed. 2002, 41, 48e76.
8. Schneider, H.-J. Angew. Chem., Int. Ed. 2009, 48, 3924e3977.
9. (a) Berlin, L.; Reister, O. In Methoden der Organischen Chemie; Miller, E. B., Ed.;
Georg Thieme: Stuttgart, Germany, 1972; Vol. 5/1d, pp 227e299; (b) Panigrahi,
M.; Dash, S.; Patel, S.; Mishra, B. K. Tetrahedron 2012, 68, 781e805.
10. (a) McOmie, J. F. W. Protective Groups in Organic Chemistry; Plenum: London,
ꢁ
UK, New York, NY, 1973; (b) Clave, G.; Bernardin, A.; Massonneau, M.; Renarda,
P. Y.; Romieu, A. Tetrahedron Lett. 2006, 47, 6229e6233.
11. (a) Zhou, Z.; Tang, Y.; Whitten, D. G.; Achyuthan, K. E. Appl. Mater. Interfaces
2009, 1, 162e170; (b) Steinger, R.; Reber, J. -F.; Ezekiel, A. D.; Ficken, G. E. Ger.
Patent 2611025, 1977; Chem. Abstr. 1977, 87, 125337t; (c) Shigefuji, O.
JP2004184282 (A), 2004; Chem. Abstr. 2004, 141, 67858.
12. (a) Reitser, O.; Wilmanns, G. U.S. Patent 2,238,231, 1941; Chem. Abstr. 1941, 35,
49678; (b) Narayanan, N.; Patonay, G. J. Org. Chem. 1995, 60, 2391e2395.
13. Dalwing, J.; Hagen, D.; Huang, T.; Thomas, J.; Yue, S. WO Patent 2005056689,
2005; Chem. Abstr. 2005, 143, 61414.
14. Nys, J. M.; Depoorter, H. Ger. Patent 1081311, 1962; Chem. Abstr. 1962, 57, 328g.
15. Fry, D. G.; Kendall, J. D.; Morgan, A. J. G.B. Patent 870633, 1961; Chem. Abstr.
1961, 55, 24336i.
16. (a) Stoeckli-Evans, H. Helv. Chim. Acta 1974, 57, 1e9; (b) Nakao, K.; Yakeno, K.;
Yoshioka, H.; Nakatsu, K. Acta Crystallogr., Sect. B 1979, 35, 415e419; (c) Allmann,
R.; Waskowska, A.; Olejnik, S. Cryst. Struct. Commun. 1982, 11, 1077e1082; (d)
Yagupolskii, L. M.; Kondratenko, N. V.; Chernega, O. I.; Chernega, A. N.; Buth, S. A.;
Yagupolskii, Yu. L. Dyes Pigments 2008, 79, 242e246; (e) Shibaeva, R. P.;
Atovmyan, L. O.; Ponomarev, V. I.; Filipenko, O. S.; Rozenberg, L. P. Kristallografiya
(Crystallogr. Rep.) 1974, 19, 95e102; (f) Grossel, M. C.; Evans, F. A.; Hriljac, J. A.;
Prout, K.; Weston, S. C. J. Chem. Soc., Chem. Commun. 1990, 1494e1495.
17. (a) Stegmann, H. B.; Deuschle, G.; Schuler, P. J. Chem. Soc., Perkin Trans. 2 1994,
547e555; (b) Yuan, D.-Q.; Yang, C.; Fukuda, T.; Fujita, K. Tetrahedron Lett. 2003,
Acknowledgements
Financial support from the Russian Foundation for Basic Re-
search, the Russian Academy of Sciences, the Royal Society of
Chemistry (L.G.K.), and the EPSRC for a Senior Research Fellowship
(J.A.K.H.) is gratefully acknowledged.
References and notes
1. (a) Brooker, L. G. S.; White, F. L.; Sprague, R. H.; Dent, S. G.; Van Zandt, G. Chem.
Rev. 1947, 41, 325e351; (b) Hamer, F. M. In The Chemistry of Heterocyclic Com-
pounds; Weissberger, A., Ed.; InterScience: New York, 1964; Vol. 18, pp 1e790;
(c) Ficken, G. E. In The Chemistry of Synthetic Dyes; Venkataraman, K., Ed.; Ac-
ademic: New York, NY, 1971; Vol. 4, pp 212e340; (d) James, T. H. The Theory of

S.P. Gromov et al. / Tetrahedron 69 (2013) 5898e5907
5907
44, 565e568; (c) Stoikov, I. I.; Yushkova, E. A.; Zharov, I.; Antipin, I. S.; Kono-
valov, A. I. Tetrahedron 2009, 65, 7109e7114; (d) Sueda, T.; Oshima, A.; Teno, N.
Org. Lett. 2011, 13, 3996e3999.
298, 251e261; (c) Gromov, S. P.; Vedernikov, A. I.; Ushakov, E. N.; Lobova, N. A.;
Botsmanova, A. A.;Kuz’mina, L.G.;Churakov, A. V.;Strelenko, Yu.A.;Alfimov, M.V.;
Howard, J. A. K.; Johnels, D.; Edlund, U. G. New J. Chem. 2005, 29, 881e894; (d)
Vedernikov, A. I.; Ushakov, E. N.; Efremova, A. A.; Kuz’mina, L. G.; Moiseeva, A. A.;
Lobova, N. A.; Churakov, A. V.; Strelenko, Yu. A.; Alfimov, M. V.; Howard, J. A. K.;
Gromov, S. P. J. Org. Chem. 2011, 76, 6768e6779.
ꢁ
18. Chipon, B.; Clave, G.; Bouteiller, C.; Massonneau, M.; Renard, P.-Y.; Romieu, A.
Tetrahedron Lett. 2006, 47, 8279e8284.
19. (a) Gromov, S. P.; Ushakov, E. N.; Vedernikov, A. I.; Lobova, N. A.; Alfimov, M. V.;
Strelenko, Yu. A.; Whitesell, J. K.; Fox, M. A. Org. Lett. 1999, 1, 1697e1699; (b)
Ushakov, E. N.; Nadtochenko, V. A.; Gromov, S. P.; Vedernikov, A. I.; Lobova, N. A.;
Alfimov, M. V.; Gostev, F. E.; Petrukhin, A. N.; Sarkisov, O. M. Chem. Phys. 2004,
20. Eriks, J. C.; van der Goot, H.; Stark, G. J.; Timmerman, H. J. Med. Chem. 1992, 35,
3239e3246.
21. SHELXTL-Plus, Version 5.10; Bruker AXS: Madison, WI, USA, 1997.