Synthesis of new rhodacyanines analogous to MKT-077 under microwave irradiation

Article abstract of DOI:10.1080/00397910701575400

We report here a synthesis of a new rhodacyanines 7X analogous to MKT-077 with quantitative yield using as starting material the thiazolinethione 1. Merocyanines 4 and their tosylates 5 have been prepared as intermediates for this class of compounds. The reactions leading to rhodacyanine 7X have been studied under microwave irradiation. Copyright Taylor & Francis Group, LLC.

Full text of DOI:10.1080/00397910701575400

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Synthesis of New Rhodacyanines Analogous to
MKT‐077 under Microwave Irradiation
Souad Kasmi‐Mir a , Ayada Djafri b , Jack Hamelin c , Ludovic Paquin c , Jean
Pierre Bazureau c & Mustapha Rahmouni d
a Laboratory Synthesis and Catalyses, LSCT , University of Ibn Khaldun ,
Tiaret, Algéria
b Ayada Djafri Organic Laboratory Synthesis Applied , University of Essénia ,
Oran, Algéria
c University of Rennes 1, Synthesis and Electrosynthesis Organic 3 , Rennes
Cedex, France
d Mustapha Rahmouni Laboratory Synthesis and Catalyses, LSCT, University
of Ibn Khaldun , Tiaret, Algéria
Published online: 19 Nov 2007.
To cite this article: Souad Kasmi‐Mir , Ayada Djafri , Jack Hamelin , Ludovic Paquin , Jean Pierre Bazureau
& Mustapha Rahmouni (2007) Synthesis of New Rhodacyanines Analogous to MKT‐077 under Microwave
Irradiation, Synthetic Communications: An International Journal for Rapid Communication of Synthetic
Organic Chemistry, 37:22, 4017-4034, DOI: 10.1080/00397910701575400
To link to this article: http://dx.doi.org/10.1080/00397910701575400
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Synthetic Communicationsw, 37: 4017–4034, 2007
Copyright # Taylor & Francis Group, LLC
ISSN 0039-7911 print/1532-2432 online
DOI: 10.1080/00397910701575400
Synthesis of New Rhodacyanines
Analogous to MKT-077 under
Microwave Irradiation
Souad Kasmi-Mir
Laboratory Synthesis and Catalyses, LSCT, University of Ibn Khaldun,
´
Tiaret, Algeria
Ayada Djafri
Ayada Djafri Organic Laboratory Synthesis Applied, University
´ ´
of Essenia, Oran, Algeria
Jack Hamelin, Ludovic Paquin, and Jean Pierre Bazureau
University of Rennes 1, Synthesis and Electrosynthesis Organic 3,
Rennes Cedex, France
Mustapha Rahmouni
Mustapha Rahmouni Laboratory Synthesis and Catalyses, LSCT,
´
University of Ibn Khaldun, Tiaret, Algeria
Abstract: We report here a synthesis of a new rhodacyanines 7X analogous to
MKT-077 with quantitative yield using as starting material the thiazolinethione 1.
Merocyanines 4 and their tosylates 5 have been prepared as intermediates for this
class of compounds. The reactions leading to rhodacyanine 7X have been studied
under microwave irradiation.
Keywords: condensation, microwave irradiation, rhodacyanine cation, thiazolinethione
Received in the U.K. October 3, 2006
Address correspondence to Souad Kasmi-Mir, Laboratory Synthesis and Catalyses,
´
LSCT, University of Ibn Khaldun, Tiaret, Algeria. E-mail: kasmi@mail.univ-tiaret.dz
or kasmimir@yahoo.fr
4017

4018
S. Kasmi-Mir et al.
INTRODUCTION
Rhodacyanines dyes and several analogous delocalized lipophilic cation
(DLCs) were synthesized and evaluated as novel antitumor agents, and the
rhodanine was an essential moiety for antitumor activity.[1,2] Recently,
the discovery of the MKT-077 rhodacyanines[3] opened new prospects in
the treatment of malaria.
Knowing this, we found it interesting in this work to synthesize rhodacya-
nines 7X (which are DLCs analogous to MKT-077) under microwave
irradiation. We studied a simple synthesis starting from thiazolinethione 1
because of their known activities,[4–6] according to Scheme 1.
The iodide 2 obtained by alkylation of the thiazolinethione 1[7] is
condensed with the rhodanine 3 in the presence of Et3N to give in situ the
stable merocyanine 4. This compound is then converted in the corresponding
Scheme 1. Reagents and reaction conditions: (i) MeI (2 eq), acetone, rt, 24 h; (ii) 3
(1 eq), Et3N (1.5 eq), acetone, rt, 24 h; MW: 508C, 5–10 min; (iii) MPTS (3 eq),
DMF, 110–1208C, 4 h; MW: MPTS (3 eq), 1208C, 20 min (IVi) 6X (1 eq), Et3N
(1.5 eq), MeCN, reflux, 4 h; MW: 6X (1 eq), Et3N (1.5 eq), 858C, 30 min.

New Rhodacyanines
4019
Table 1. Results of merocyanines 4(a–f)
Yields of Yields of Time (min) lmax
4 (%)a
Compounds
R1
R2
4 (%)b
MW
(nm)c
4a
4b
4c
4d
4e
4f
Me
Ph
Me
Me
Me
95
88
95
70
30
60
97
80
96
85
62
70
5
5
432
428
432
434
436
431
pC6H4Me
Me
Ph
10
10
5
pC6H4Me
pC6H4Me
pC6H4Me
pC6H4Me
5
aClassical heating (Ch), isolated yield.
bMicrowave irradiation (MW), isolated yield.
cUV-vis spectra were measured in CHCl3 solution.
tosylate 5, which is also stable, by reaction with an excess of methylparatolue-
nesulfonate (MPTS). The salt 5 finally reacts with the quaternary pyridinium
salt 6X, which acts as a nucleophile in the presence of Et3N according to the
method of Brooker[8] and gives the desired rhodacyanine 7X. The results are
summarized in Tables 1 to 3.
RESULTS AND DISCUSSION
Satisfactory yield are obtained in both cases (i.e., classical heating, with a
small amount of solvent or microwave irradiation at nearly the same tempera-
ture without solvent). In the latter case, the purity of the compounds is higher,
and obviously the reaction time is reduced.
The structural assignments of 4, 5, and 7X are established by 1H and 13C
NMR. They all exhibit a typical low-field signal for the H5 proton of the
thiazolic cycle around 6.30 to 6.75 ppm (4), 6.82–7.12 ppm (5), and
6.37–6.93 ppm (7X).
Table 2. Results of tosylates 5(a–f)
Yields of 5
(%)a
Yields of 5
(%)b
Compounds
R1
R2
5a
5b
5c
5d
5e
5f
Me
Ph
Me
Me
Me
72
82
63
92
75
66
65
78
72
85
68
73
pC6H4Me
Me
Ph
pC6H4Me
pC6H4Me
pC6H4Me
pC6H4Me
aClassical heating (Ch), isolated yield.
bMicrowave irradiation (MW), isolated yield.

4020
S. Kasmi-Mir et al.
Table 3. Results of the rhodacyanines 7(a–f) X
Yields of Yields of
7X (%)a
l
max
(nm)b
Compounds
R1
R2
X
7X (%)c
7aT
7aI
7bT
7bI
7cT
7cI
Me
Me
Ph
Me
Me
Me
Me
ptos
78
70
72
62
60
54
70
72
65
75
72
74
90
82
85
79
78
76
88
93
77
84
85
88
505
502
502
501.5
508
518
508
516
508
506
504
520
I
ptos
Ph
I
pC6H4Me Me
pC6H4Me Me
ptos
I
7dT
7dI
7eT
7eI
Me
Me
Ph
pC6H4Me ptos
pC6H4Me
pC6H4Me ptos
pC6H4Me
I
Ph
I
7fT
7fI
pC6H4Me pC6H4Me ptos
pC6H4Me pC6H4Me
I
aClassical heating (Ch), isolated yield.
bUV-vis spectra were measured in CHCl3 solution.
1
cYield estimated by H NMR for MW experiments.
The 13C NMR spectra show a signal around 164.93–166.30 ppm (4),
160.36–163.30 ppm (5), and 163.02–164.80 ppm (7X), typical of C4 of the
rhodanine cycle.
All the compounds 7X exhibit a singlet around 5.19–5.77 ppm for the
exocyclic double-bond proton, which shows that Brooker condensation is
stereospecific. In all cases, only the (2Z, 5E) stereoisomer is formed (54–78%),
in agreement with previous results related to MKT-077 synthesis.[1–3]
We observed a bathochromic effect for the merocyanine 4 and rhodacya-
nine 7X.
In conclusion, we showed that microwave irradiation without solvent was
suitable for this type of synthesis, leading to higher yield in quite short
reaction times (5 to 30 min) and is a more ecofriendly process.[9]
EXPERIMENTAL
General
Melting points were determined on a Kofler melting-point apparatus and are
uncorrected. IR spectra were taken with a Perkin-Elmer 1420 spectrometer.1H
NMR spectra were recorded on Bruker ARX 200 (200 MHz) and Bruker AC
300P (300 MHz) spectrometers, and 13C NMR spectra were measured on a
Bruker AC 300P (75 MHz) spectrometer. Chemical shifts are expressed in
parts per million downfield from tetramethylsilane as an internal standard.
The mass spectra (MS) were measured on a Variant MAT 311 at a ionizing

New Rhodacyanines
4021
potential of 70 eV in the Centre de Mesures Physiques de l’Ouest (CRMPO,
Rennes). The sources are electronic impact (EI) and electrospray (ESI).
Elemental analysis was performed at the Centre de Mesures Physiques de
l’ Ouest (CRMPO, Rennes). The UV-vis spectra were recorded on a UV-vis
Spectrometer Pye Unicam at Tiaret University. Reactions under microwave
irradiation were performed in a Prolabo Synthewave 402 (2.45-GHz)
microwave reactor with a single focused system. All solvents and reagents
were purchased from Acros Organics and Aldrich Chemic and used without
further purification unless otherwise stated.
Compound 1
The preparation of the compounds 1 was obtained according to the literature[7]
from disulfide carbon, amine in aqueous ammonia, and chloro acetone by
Hantzsch’s cyclization.
3,4-Dimethyl-1,3-thiazole-2(3H)-thione (1a). Beige crystals; yield ¼ 80%;
1
mp ¼ 1158C (lit. 119–1148C). H NMR (200 MHz, CDCl3) d: 6.30 (s, 1H);
3.68 (s, 3H); 2.31 (s, 3H). 13C NMR (50 MHz CDCl3) d: 187.8; 139.9;
105.9; 34.1; 15.7.
4-Methyl-3-phenyl-1,3-thiazole-2(3H)-thione (1b). White crystals; yield ¼
1
80%; mp ¼ 1508C; H NMR (200 MHz, CDCl3) d: 7.20–7.65 (m, 5Har);
3
6.39 (s, 1H); 1.99 (s, 3H); C NMR (50 MHz, CDCl3): d ¼ 190.2; 140.1;
137.8; 130.7; 128.1, 127. 5, 106.3; 16.1.
4-Methyl-3-(4-methylphenyl)-1,3-thiazole-2-(3H)-thione (1c). Beige crystals;
yield ¼ 95%; mp ¼ 1108C; 1H NMR (200 MHz, CDCl3) d: 7.30 (d, 2H); 7.12
(d, 2H) 6.34 (s, 1H); 2.42 (s, 3H); 1.95 (s, 3H); 13C NMR (50 MHz, CDCl3)
d: 190.1; 10.3; 139.7; 135.1; 130.6; 127.8; 127.7; 127.7; 106.2; 21.3; 16.1.
Compound 2
3,4-Dimethyl-2-(methylthio)-1,3-thiazol-3ium Iodide (2a). The alkylation
of 1a (4.35 g; 30 mmol) with iodomethane (8.52 g; 60 mmol) gave 2a
(6.45 g; 75%).
2a: pale yellow needles; mp ¼ 1628C; 1H NMR (200 MHz, CDCl3 þ TFA) d:
7.59 (s, 1H); 3.92 (s, 3H); 2.98 (s, 3H); 2.59 (s, 3H).
4-Methyl-3phenyl-2-(methylthio)-1,3-thiazol-3ium Iodide (2b). The alky-
lation of 1b (4.14 g; 20 mmol) with iodomethane (5.68 g; 40 mmol) gave
2b (5.16 g; 74%).

4022
S. Kasmi-Mir et al.
2b: pale pink needles; yield: 74%; mp ¼ 1938C; 1H NMR (200 MHz,
CDCl3 þ TFA) d: 7.47–7.79 (m, 5Har); 7.46 (s, 1H); 2.93 (s, 3H,); 2.30
(s, 3H).
´
4-Methyl-3-(4-methylphenyl)-2-(methylthio)-1,3-thiazol-ium (2c). The alky-
lation of 1c (4.40 g; 20 mmol) with iodomethane (5.68 g; 40 mmol) gave 2c
(5.87 g; 81%).
2c: bricked crystals; yield ¼ 81%; mp ¼ 1608C; 1H NMR (200 MHz,
CDCl3 þ TFA) d: 8.22 (s, 1H); 7.7 (m, 4H); 2.95 (s, 3H); 2.50 (s, 3H); 2.27
(s, 3H).
Compound 3
The preparation of the compounds 3 was obtained according to the litera-
ture[10a] from disulfide carbon, amine in aqueous ammonia, and chloroacetic
acid by Hantzsch’s cyclization.
3-Methyl-2-thioxo-1,3-thiazolidin-4-one (3a). Yellow crystals; yield ¼ 75%;
mp ¼ 718C (lit. 69–718C); 1H NMR (200 MHz, CDCl3) d: 4.10 (s, 2H); 3.40
(s, 3H); 13C NMR (CDCl3): d ¼ 201.1; 173.3; 35.6; 31.2.
´
3-(4-Methylphenyl)-2-thioxo-1,3-thiazolidin-4-one (3b). Yellow crystals;
1
yield ¼ 68%; mp ¼ 1528C; H NMR (200 MHz, CDCl3) d: 7.33 (d, 2H,
J ¼ 6.0 Hz); 7.07 (d, 2H, J ¼ 6.1 Hz); 4.17 (s, 2H); 2.40 (s, 3H); 13C NMR
(50 MHz, CDCl3) d: 201.3; 173.5; 140.0; 132.2; 130.2; 128.0; 125.5; 120.7;
36.3; 21.3.
General Process for Merocyanine 4
Classical Heating (Ch)
In a 250-ml round-bottomed flask, 10 mmol of salt 2, 10 mmol of rhodanine 3,
20 ml of acetone, and 2 ml of triethylamine are placed. After stirring at room
temperature during one night or at reflux during 1 h, a yellow-green solid is
formed. It is filtered off and washed several time with aceton.
Microwave Irradiation (MW)
In a cylindrical quartz reactor (F ¼ 1.5 cm), 1.39 mmol of the iodide 2,
rhodanine 3 (1.39 mmol), and 0.28 ml of triethylamine are placed.
Microwave irradiation under stirring is applied at 508C for 5 to 10 min (by
monitoring the temperature). After cooling to room temperature, the yellow
product is washed with acetone and then dried under vacuum.

New Rhodacyanines
4023
(5E)-3-Methyl-5-(3,4-dimethylthiazol-2(3H)-ylidene)-2-thioxothiazolidin-
4-one (4a). The condensation of 2a (2.87 g; 10 mmol) with 3a (1.47 g;
10 mmol) gave 4a (2.45 g; 95%) in classical heating, and the condensation of
2a (400 mg; 1.39 mmol) with 3a (204 mg; 1.39 mmol) gave 4a (358 mg;
97%) in MW.
1
4a: yellow-green powder; mp . 2608C. H NMR (300 MHz, CDCl3) d: 6.30
(s, 1H, H5); 3.78 (s, 3H, CH3Nthiazol); 3.55 (s, 3H; CH3rhod); 2.30 (s, 3H,
CH3-C4). 13C NMR (75 MHz, CDCl3) d: 189.3 (C55S); 164.9 (C55O); 157.3
(C2thiazol); 137.3 (C4thiazol); 109.8 (C5thiazol, d, J ¼ 186.1 Hz); 84.9
(C5rhod); 34.8 (q, J ¼ 140.0 Hz, CH3Nthiazol); 31.3 (q, J ¼ 142.1 Hz,
CH3rhod); 14.6 (qd, J ¼ 130.2 Hz, J ¼ 2.2 Hz, CH3C4). HRMS (EI) Mþfor
C9H10N2OS3 calcd.: 257.99553; found: 257.995.
(5E)-3-Methyl-5-(4-methyl-3-phenylthiazol-2(3H)-ylidene)-2-thioxothiazol-
idin-4-one (4b). The condensation of 2b (3.49 g; 10 mmol) with 3a (1.47 g;
10 mmol) gave 4b (2.82 g; 88%) in classical heating, and the condensation of
2b (485 mg; 1.39 mmol) with 3a (204 mg; 1.39 mmol) gave 4b (360 mg;
80%) in MW.
4b: yellow powder; yield ¼ mp . 2608C. 1H NMR (300 MHz, CDCl3 þ CF3-
COOH) d: 7.76–7.33 (m, 5Har); 6.75 (s, 1H, H5); 3.46 (s, 3H, CH3rod); 1.98
(s, 3H, CH3C4). 13C NMR (75 MHz, CDCl3 þ CF3COOH) d: 187.4 (C55S);
165.2 (C55O); 157.0 (C2thiazol); 138.8 (C4thiazol); 132.2; 130.8; 129.0;
116.6; 112.8 (Car); 109.0 (C5thiazol, dq, J ¼ 186.1 Hz, J ¼ 5.0 Hz); 85.0
(C5rhod); 31.5 (q, J ¼ 142.0 Hz, CH3 rhod); 14.3 (qd, J ¼ 130.5 Hz;
J ¼ 2.1 Hz; CH3-C4). HRMS (EI) Mþ. for C14H12N2OS3 calcd.:
320.01118; found: 320.0124.
(5E)-3-Methyl-5-(4-methyl-3-p-tolylthiazol-2(3H)-ylidene)-2-thioxothiazol-
idin-4-one (4c). The condensation of 2c (3.63 g; 10 mmol) with 3a (1.47 g;
10 mmol) gave 4c (3.18 g; 95%) in classical heating, and the condensation of
2c (504 mg; 1.39 mmol) with 3a (204 mg; 1.39 mmol) gave 4c (464 mg;
96%) in MW.
1
4c: brown yellow powder; mp .2608C. H NMR (300 MHz, CDCl3 þ CF3-
COOH) d: 7.43 (d, 2H, J ¼ 8.07 Hz); 7.18 (d, 2H, J ¼ 8.25 Hz); 6.58
(s, 1H, H5); 3.48 (s, 3H, CH3Nrhod); 2.30 (s, 3H, pCH3); 1.98 (s, 3H,
CH3C4). 13C NMR (75 MHz, CDCl3 þ CF3COOH) d: 186.2 (C55S); 166.3
(C55O); 157.2 (C2thiazol); 143.0 (C4thiazol); 131.8; 128.5; 120.3; 116.5;
106.0 (dq, J ¼ 188.0 Hz, J ¼ 5.1 Hz); 84.2 (C5rhod); 31.6 (q, J ¼ 142.6 Hz,
CH3rhod); 21.5 (qt, J ¼ 127.2 Hz, J ¼ 4.2 Hz, pCH3thiazol); 14.4 (qd,
J ¼ 130.6 Hz, J ¼ 2.1 Hz; CH3C4). HRMS (EI) Mþ for C15H14N2OS3
calcd.: 334. 02683; found: 334.0273.

4024
S. Kasmi-Mir et al.
(5E)-5-(3,4-Dimethylthiazol-2(3H)-ylidene)-2-thioxo-3-p-tolylthiazolidin-
4-one (4d). The condensation of 2a (2.87 g; 10 mmol) with 3b (2.23 g;
10 mmol) gave 4d (2.30 g; 70%) in classical heating, and the condensation
of 2a (400 mg; 1.39 mmol) with 3b (310 mg; 1.39 mmol) gave 4d (390 mg;
85%) in MW.
1
4d: powder; mp ¼ 2668C. H NMR (300 MHz, CDCl3 þ CF3COOH F) d:
7.38 (d, 2H, J ¼ 7.9 Hz); 7.21 (d, 2H, J ¼ 2.2 Hz); 6.7 (s, 1H, H5); 3.87
(s, 3H, CH3Nthiazol); 2.44 (s, 3H, pCH3); 2.34 (s, 3H, CH3C4). 13C NMR
(75 MHz, CDCl3 þ CF3COOH) d: 187.6 (C55S); 165.3 (C55O); 158.7
(C2thiazol); 140.1 (C4thiazol); 133.5; 130.6; 128.5 (Car); 106.7 (dq,
J ¼ 190.7 Hz, J ¼ 5.2 Hz, C5thiazol); 83.2 (C5rhod); 35.6 (q, J ¼ 141.0 Hz,
CH3-Nthiazol); 21.7 (qt, J ¼ 126.5 Hz, J ¼ 4.3 Hz, pCH3); 15.1 (qd,
J ¼ 130.2 Hz, J ¼ 2.3 Hz, CH3C4). HRMS (EI) Mþ. for C15H14N2OS3
calcd.: 334.02683; found: 334.0273.
(5E)-5-(4-Methyl-3-phenylthiazol-2(3H)-ylidene)-2-thioxo-3-p-tolylthiaz-
olidin-4-one (4e). The condensation of 2b (3.49 g; 10 mmol) with 3b (2.23 g;
10 mmol) gave 4e (1.18 g; 30%) in classical heating, and the condensation of 2b
(485 mg; 1.39 mmol) with 3b (310 mg; 1.39 mmol) gave 4e (340 mg; 62%) in
MW.
1
4e: green power; mp . 2608C. H NMR (300 MHz, CDCl3) d: 7.72–7.13
(m, 9Har); 6.36 (s, 1H, H5); 2.38 (s, 3H, pCH3); 1.98 (s, 3H, CH3C4).13C
NMR (75 MHz, CDCl3) d: 189.1 (C55S); 165.5 (C55O); 155.6 (C2 thiazol);
139.0 (C4thiazol); 137.5; 135.0; 133.4; 131.7; 130.5; 129.9; 129.2;
128.0 (Car); 104.2 (dq, J ¼ 191.0 Hz, J ¼ 5.2 Hz, C5thiazol); 84.6
(C5rhod); 21.3 (qt, J ¼ 126.1 Hz, J ¼ 4.3 Hz, pCH3); 14.4 (qd,
J ¼ 130.2 Hz, J ¼ 2.2 Hz, CH3C4). HRMS (EI) Mþ for C20H16N2OS3
calcd.: 396.0422248; found: 396.0412.
(5E)-5-(4-Methyl-3-p-tolylthiazol-2(3H)-ylidene)-2-thioxo-3-p-tolylthiazoli-
din-4-one (4f). The condensation of 2c (3.63 g; 10 mmol) with 3b (2.23 g;
10 mmol) gave 4f (2.46 g; 60%) in classical heating, and the condensation of
2c (504 mg; 1.39 mmol) with 3b (310 mg; 1.39 mmol) gave 4f (400 mg;
70%) in MW.
1
4f: yellow crystals; mp . 2608C. H NMR (300 MHz, CDCl3) d: 7.70–7.17
(m, 8Har); 6.40 (s, 1H, H5); 2.56 (s, 3H, pCH3thiazol); 2.20 (s, 3H,
p CH3rhod); 1.97 (s, 3H, CH3C4). 13C NMR (75 MHz, CDCl3) d: 189.6
(C55S); 165.9 (C55O); 156.3 (C2thiazol); 142.6 (C4thiazol); 139.4; 138.1;
133.9; 132.7; 131.5; 130.4; 129.3; 128.4 (Car); 104.5 (qd, J ¼ 191.0 Hz,
J ¼ 5.3 Hz, rhod); 84.9 (C5rhod); 22.0 (qt, J ¼ 127.3 Hz, J ¼ 4.2 Hz, CH3
thiazol); 21.7 (qt, J ¼ 126.7 Hz, J ¼ 4.5 Hz, pCH3rhod); 14.8 (qd,
J ¼ 130.3 Hz, J ¼ 2.1 Hz, CH3C4). HRMS (EI) Mþ for C21H18N2OS3
calcd.: 410.05813; found: 410.0598.

New Rhodacyanines
4025
General Procedure for Salts Tosylates 5
Classical Heating (Ch)
A mixture of 4 (5 mmol), 15 mmol of MPTS (methyl paratoluensulfonate),
and 5 ml of DMF is stirred at 110–1208C during 4 h. The reaction mixture
is cooled down to 408C, and 50 ml of acetone is added. After completion,
the mixture is cooled down to room temperature and then refrigerated for
one night. The resulting salt is filtered off and dried under vacuum.
Microwave Irradiation (MW)
In the previous quartz reactor, 3.1 mmol of merocyanine 4 and 9.3 mmol of
MPTS are added. After irradiation at 1208C during 20 min the tosylate 5 is
collected and washed with acetone.
(5E)-3-Methyl-5(3,4-dimethyl-1,3-thiazol-2-ylidene)-2-(methylthio)-4-oxo-1,
3-thiazolium p-toluenesulfonate (5a). The alkylation of 4a (1.29 g; 5 mmol)
with MPTS (2.79 g; 15 mmol) gave 5a (1.59 g; 72%) in classical heating, and
the alkylation of 4a (800 mg; 3.1 mmol) with MPTS (1.73 g; 9.3 mmol) gave
5a (894 mg; 65%) in MW.
1
5a: yellow-green powder; mp ¼ 2528C. H NMR (300 MHz, CDCl3 þ CF3
COOH) d: 7.90 (d, 2H, J ¼ 8.0 Hz); 7.18 (d, 2H, J ¼ 8.0 Hz); 7.02 (s, 1H,
H5); 4.12 (s, 3H, CH3Nthiazol); 3.73 (s, 3H, CH3Nþ); 2.99 (s, 3H, CH3-S);
2.50 (s, 3H, CH3tos); 2.11 (s, 3H, CH3C4). 13C NMR (75 MHz, CDCl3 þ CF3
COOH) d: 174.0 (C-S); 160.3 (C55O); 159.5 (C2thiazol); 142.6 (C4thiazol);
141.4; 130.3; 129.3; 126.2 (Car); 106.2 (qd, J ¼ 196.1 Hz, J ¼ 5.2 Hz, C5);
84.9 (C5rhod); 37.0 (q, J ¼ 144.1 Hz, CH3 Nthiazol); 33.8 (q, J ¼ 143.8 Hz,
CH3Nþ); 21.6 (qt, J ¼ 126.4 Hz, J ¼ 4.4 Hz, CH3tos); 16.2 (q, J ¼ 145.0 Hz,
CH3-S); 14.1 (qd, J ¼ 129.1 Hz, J ¼ 2.2 Hz, CH3C4). HRMS (ESI) Mþ for
C10H13N2OS3 calcd.: 273.01900; found: 273.0186. The ionization clusters
(2Cþ, Tos2)þ are found at m/z 717.
(5E)-3-Methyl-5(4-methyl-3-phenyl-1,3-thiazol-2-ylidene)-2-(methylthio)
-4-oxo-1,3-thiazolium p-toluenesulfonate (5b). The alkylation of 4b (1.60 g;
5 mmol) with MPTS, (2.79 g; 15 mmol) gave 5b (2.07 g; 82%) in classical
heating, and the alkylation of 4b (1.00 g; 3.1 mmol) with MPTS (1.73 g;
9.3 mmol) gave 5b (1.22 g; 78%) in MW.
1
5b: deep green crystals; mp ¼ 2058C. H NMR (300 MHz, CDCl3 þ CF3
COOH) d: 7.79–7.74 (m, 5Har); 7.72 (d, 2H, J ¼ 8.0 Hz); 7.69 (d, 2H,
J ¼ 8.0 Hz); 7.12 (s, 1H, H5); 3.50 (s, 3H, CH3Nþ); 2.6 (s, 3H, CH3-S);
2.29 (s, 3H, CH3tos); 2.08 (s, 3H, CH3C4). 13C NMR (75 MHz, CDCl3 þ CF3
COOH) d: 175.9 (C-S); 162.4 (C55O); 160.9 (C2thiazol); 143.2 (C4thiazol);

4026
S. Kasmi-Mir et al.
140.4; 139.2; 134.9; 132.9; 131.1; 128.8; 128.4; 126.1 (Car); 109.2 (dq,
J ¼ 196.0 Hz, J ¼ 5.1 Hz, C5); 84.6 (C5rhod); 32.6 (q, J ¼ 143.8 Hz,
CH3Nþ); 21.3 (qt, J ¼ 126.4 Hz, J ¼ 4.4 Hz, CH3tos); 15.9
(q, J ¼ 145.0 Hz, CH3-S); 14.2 (qd, J ¼ 130.1 Hz, J ¼ 2.1 Hz, CH3thiazol).
HRMS (ESI) Mþ for C15H15N2OS3 calcd.: 335.0365; found: 335.035. The
ionization cluster (2Cþ, Tos2)þ is found at m/z 841.
(5E)-3-Methyl-5[4-Methyl-3-(4-methylphenyl)-1,3-thiazol-2-ylidene]-2-(met-
hylthio)-4-oxo-1,3-thiazolium p-toluenesulfonate (5c). The alkylation of 4c
(1.67 g; 5 mmol) with MPTS, (2.79 g; 15 mmol) gave 5c (1.63 g; 63%) in
classical heating, and the alkylation of 4c (1.04 g; 3.1 mmol) with MPTS
(1.73 g; 9.3 mmol) gave 5c (1.16 g; 72%) in MW.
1
5c: deep green crystals; mp ¼ 1988C. H NMR (300 MHz, CDCl3) d: 7.76
(d, 2H, J ¼ 8.0 Hz); 7.57 (d, 2H, J ¼ 8.1 Hz); 7.32 (d, 2H, J ¼ 8.2 Hz);
7.11 (d, 2H, J ¼ 8.0 Hz); 7.05 (s, 1H, H5); 3.56 (s, 3H, CH3Nþ); 2.73
(s, 3H, CH3S); 2.48 (s, 3H, pCH3thiazol); 2.32 (s, 3H, CH3tos); 2.11 (s, 3H,
CH3C4 CH3tos). 13C NMR (75 MHz, CDCl3) d: 175.8 (C-S); 162.2
(C55O); 160.4 (C2thiazol); 143.8 (C4thiazol); 143.6; 141.6; 140.7; 138.8;
133.0; 131.5; 129.3; 129.0; 126.8 (Car); 109.3 (dq, J ¼ 191.3 Hz,
J ¼ 5.3 Hz, C5thiazol); 85.5(C5rhod); 32.5 (q, J ¼ 144.2 Hz, CH3Nþ); 21.5
(qt, J ¼ 127.6 Hz, J ¼ 4.2 Hz, pCH3thiazol); 21.2 (qt, J ¼ 126.4 Hz,
J ¼ 5.0 Hz, CH3tos); 15.9 (qt, J ¼ 126..4 Hz, J ¼ 4.5 Hz, pCH3tos); 14.4
(q, J ¼ 144.9 Hz, CH3-S); 14.2 (qd, J ¼ 131.1 Hz, J ¼ 2.1 Hz, CH3C4).
HRMS (ESI) Mþfor C16H17N2OS3 calcd.: 349.05030; found: 349.0509.
The ionization clusters (2Cþ, Tos2)þ are found at m/z 869.
(5E)-3-(4-Methylphenyl)-5-(3,4-dimethyl-1,3-thiazol-2-ylidene)-2-(methyl
thio)-4-oxo-1,3-thiazolium p-toluenesulfonate (5d). The alkylation of 4d
(1.67 g; 5 mmol) with MPTS (2.79 g; 15 mmol) gave 5d (2.39 g; 92%) in cl
assical heating, and the alkylation of 4d (1.05 g; 3.1 mmol) with MPTS
(1.73 g; 9.3 mmol) gave 5d (1.37 g; 85%) in MW.
5d: orange crystals; mp ¼ 2448C. 1H NMR (300 MHz, CDCl3) d: 7.75 (d, 2H,
J ¼ 8.0 Hz); 7.43 (d, 2H, J ¼ 8.0 Hz); 7.28 (d, 2H, J ¼ 8.1 Hz); 7.0 (d, 2H,
J ¼ 7.5 Hz); 6.82 (s, 1H, H5); 4.30 (s, 3H, CH3thiazol); 3.03 (s, 3H, CH3-S);
2.48 (s, 3H, pCH3tos); 2.44 (s, 3H, CH3rhod); 2.34 (s, 3H, CH3-C4). 13C NMR
(75 MHz, CDCl3) d: 175.7 (C-S); 163.3 (C55O); 161.5 (C2thiazol); 144.0
(C4thiazol); 142.3; 141.7; 140.5; 139.5; 132.9; 132.2; 131.3; 128.9; 126.3
(Car); 109.7 (dq, J ¼ 196.2 Hz, J ¼ 5.3 Hz, C5thiazol); 86.2 (C5rhod); 38.0
(q, J ¼ 144.1 Hz, CH3thiazol); 21.8 (qt, J ¼ 127.1 Hz, J ¼ 3.0 Hz,
pCH3rhod); 21.6 (qt, J ¼ 126.6 Hz, J ¼ 4.5 Hz, CH3tos); 16.8
(q, J ¼ 14.8 Hz, CH3S); 15.0 (qd, J ¼ 131.2 Hz, J ¼ 2.3 Hz, CH3C4). HRMS
(ESI) Mþ for C16H17N2OS3 calcd.: 349.05030; found: 349.0512. The ionization
clusters (2Cþ, Tos2)þ are found at m/z 869.

New Rhodacyanines
4027
(5E)-3(4-Methylphenyl)-5(4-methyl-3-phenyl-1,3-thiazol-2-ylidene)-2-(met
hylthio)-4-oxo-1,3-thiazolium p-toluenesulfonate (5e). The alkylation of 4e
(1.98 g; 5 mmol) with MPTS (2.79 g; 15 mmol) gave 5e (2.17 g; 75%) in
classical heating, and the alkylation of 4d (1.24 g; 3.1 mmol) with MPTS
(1.73 g; 9.3 mmol) gave 5e (1.22 g; 68%) in MW.
1
5e: green crystals; mp ¼ 2348C. H NMR (300 MHz, CDCl3) d: 7.80–7.06
(m, 13Har); 7.03 (s, 1H, H5); 2.52 (s, 3H, pCH3rhod); 2.41 (s, 3H, CH3-S);
2.28 (s, 3H, CH3tos); 2.06 (s, 3H, CH3thiazol). 13C NMR (75 MHz, CDCl3)
d: 177.3 (C-S); 162.6 (C55O); 161.0 (C2thiazol); 143.8 (C4thiazol); 141.7;
140.5; 138.8; 134.2; 132.9; 132.0; 130.7; 129.13; 128.6; 128.4; 127.2; 126.6
(Car); 109.3 (dq, J ¼ 196.5 Hz, J ¼ 5.4 Hz, C5thiazol); 86.0 (C5rhod); 21.4
(qt, J ¼ 127.2 Hz, J ¼ 3.0 Hz, pCH3rhod); 21.2 (qt, 126.8 Hz, J ¼ 4.5 Hz,
CH3tos); 15.8 (q, J ¼ 1.8 Hz, CH3-S); 14.2 (qd, J ¼ 131.1 Hz, J ¼ 2.3 Hz,
CH3C4). HRMS (ESI) Mþ for C21H19N2OS3 calcd.: 411.06595; found:
411.0656. The ionization cluster (2Cþ, Tos2)þ is not seen.
(5E)-3(4-Methylphenyl)-5-[4-methyl-3-(4-methylphenyl)-1,3-thiazol-2-ylid
ene]2(methylthio)-4-oxo-1,3-thiazolium p-toluenesulfonate (5f). The alky-
lation of 4f (2.06 g; 5 mmol) with MPTS (2.79 g; 15 mmol) gave 5f (1.98 g;
66%) in classical heating, and the alkylation of 4f (1.30 g; 3.1 mmol) with
MPTS (1.73 g; 9.3 mmol) gave 5f (1.35 g; 73%) in MW.
1
5f: deep green crystals; mp ¼ 2168C. H NMR (300 MHz, CDCl3) d: 7.75
(d, 2H, J ¼ 8.0 Hz); 7.59 (d, 2H, J ¼ 8.1 Hz); 7.35 (d, 2H, J ¼ 6.5 Hz); 7.31
(d, 2H, J ¼ 7.2 Hz); 7.25 (d, 2H, J ¼ 8.3 Hz); 7.09 (d, 2H, J ¼ 8.3 Hz); 7.03
(s, 1H, H5); 2.60 (s, 3H, CH3-S, pCH3rhod); 2.55 (s, 3H, pCH3thiazol); 2.43
(s, 3H, pCH3rhod); 2.29 (s, 3H, CH3tos); 2.08 (s, 3H, CH3C4). 13C NMR
(75 MHz, CDCl3) d: 177.5 (C-S); 162.6 (C55O); 160.1 (C2thiazol); 144.3
(C4thiazol); 141.7; 140.7; 138.5; 134.2; 132.1; 131.9; 130.9; 130.6; 129.1;
128.2; 126.6; 126.1 (Car); 109.1 (qd, J ¼ 196.1 Hz, J ¼ 5.2 Hz, C5thiazol);
86.0 (C2rhod); 21.5 (qt, J ¼ 127.1 Hz, J ¼ 4.2 Hz, pCH3thiazol); 21.4
(qt, J ¼ 127.2 Hz, J ¼ 4.3 Hz, pCH3rhod); 21.2 (qt, J ¼ 126.2 Hz,
J ¼ 4.0 Hz, pCH3tos); 15.9 (q, J ¼ 14.8 Hz, CH3-S); 14.2 (qd, J ¼ 131.0 Hz,
J ¼ 2.1 Hz, CH3C4). HRMS (ESI) Mþ for C22H21N2OS3 calcd.: 425.08160;
found: 425.0816. The ionization clusters (2Cþ, Tos2)þ is found at m/z 1021.
General Process for Pyridinium Salts 6X Preparations
A mixture of 50 mmol of 2-methylpyridine and 100 ml of iodomethane or
MPTS is stirred in acetonitrile (50 ml) for 24 h at room temperature. The
resulting salt is filtered off and washed with aceton.
1,2-Dimethylpyridinium iodide (6I). The alkylation of 2-methylpyridine
(4.65 g; 50 mmol) with iodomethane (14.2 g; 100 mmol) gave 6I (7.64 g; 65%).

4028
S. Kasmi-Mir et al.
1
6I: white crystals; mp ¼ 2448C; H NMR (200 MHz, D2O) d: 8.61 (d, 1H,
J ¼ 6.2 Hz); 8.28 (t, 1H, J ¼ 7.9 Hz); 7.83 (d, 1H, J ¼ 8.0 Hz); 7.74 (t, 1H,
J ¼ 7.0 Hz); 4.15 (s, 3H); 2.71 (s, 3H).
1,2-Dimethylpyridinium p-toluenesulfonate (6T). The alkylation of
2-methylpyridine (4.65 g; 50 mmol) with MPTS (18.62 g; 100 mmol) gave
6T (9.77 g; 70%).
1
6T: white crystals; mp ¼ 1738C. H NMR(200 MHz, D2O) d: 8.45 (d, 1H,
J ¼ 6.2 Hz); 8.16 (t, 1H, J ¼ 7.8 Hz); 7.67 (d, 1H, J ¼ 8,1 Hz); 7.58 (t, 1H,
J ¼ 6.7 Hz); 7.49 (d, 2H, J ¼ 8.2 Hz); 7.15 (d, 2H, J ¼ 8.3 Hz); 4.01
(s, 3H); 2.58 (s, 1H); 2.21 (s, 3H).
General Procedure for Rhodacyanines 7X
Classical Heating (Ch)
In a round-bottom flask, 25 ml of acetonitrile are introduced and then 5 mmol
of 5, 5 mmol of the 1,2-dimethyl pyridinium salt 6X, and 1 ml of Et3N are
added after reflux under stirring for 4 h or 24 h at room temperature. The
red reaction mixture is concentrated, and the residue is precipitated by a
minimum ethanol or EtOH/Et2O mixture.
Microwave Irradiation (MW)
In the quartz reactor, 0.53 mmol of tosylate 5 and 0.53 mmol of salt 6X are
placed in the presence of two drops of Et3N. After irradiation for 30 min at
1
858C, a deep red solid is obtained, which is analyzed by H NMR.
(2Z,5E)-1-Methyl-2-[f3-methyl-5-(3,4-dimethyl-1,3-thiazol-2-ylidene)-4-oxo
-1,3-thiazolidin-2-ylideneg] methyl] pyridinium p-toluenesulfonate (7aT).
The condensation of 5a (2.20 g; 5 mmol) with 6T (1.39 g; 5 mmol) gave 7aT
(1.96 g; 78%) in classical heating.
1
7aT: garnet red crystals; mp ¼ 2498C. H NMR (200 MHz, DMSO-d6) d:
8.55 (d, 1H, J ¼ 6.4 Hz); 8.18 (t, 1H, J ¼ 7.8 Hz); 7.86 (d, 1H, J ¼ 8.7 Hz);
7.50 (d, 2H, J ¼ 7.9 Hz); 7.25 (t, 1H, J ¼ 6.6 Hz); 7.15 (d, 2H, J ¼ 7.8 Hz);
6.78 (s, 1H, H5); 5.73 (s, 1H, CH55C2rhod); 4.06 (s, 3H, CH3Nþ); 3.85
(s, 3H, CH3N); 2.50 (s, 3H, CH3Nrhod); 2.30 (s, 3H, CH3tos); 2.26 (s, 3H,
CH3C4). 13C NMR (50 MHz, DMSO-d6) d: 163.0 (C55O); 158.1
(C2thiazol); 152.4 (C2rhod); 150.5; 146.0; 145.1; 142.3; 138.9; 137.9;
131.1; 128.4 (Car þ pyridine); 105.2 (C5thiazol); 83.1 (CH55C2); 77.8
(C5rhod); 45.1 (CH3Nþ); 35.5 (CH3Nthiazol); 30.6 (CH3Nrhod); 21.1

New Rhodacyanines
4029
(CH3tos); 14.2 (CH3C4). HRMS (ESI) Mþ for C16H18N3OS2 calcd.:
332.08913; found: 332.0896.
(2Z,5E)-1-Methyl-2-[f3-methyl-5-(3,4-dimethyl-1,3-thiazol-2-ylidene)-4-oxo
-1,3-thiazolidin-2-ylideneg]methyl]Pyridinium Iodide (7aI). The condensation
of 5a (2.20 g; 5 mmol) with 6I (1.17 g; 5 mmol) gave in classical heating 7aI
(1.60 g; 70%).
7aI: deep red powder; mp ¼ 2608C. 1H NMR (200 MHz, DMSO-d6) d: 8.55
(d, 1H, J ¼ 6.2 Hz); 8.20 (t, 1H, J ¼ 7.0 Hz); 7.89 (d, 1H, J ¼ 8. 3 Hz); 7.30
(t, 1H, J ¼ 7.1 Hz); 6.82 (s, 1H, H5); 5.77 (s, 1H, CH55C2rhod); 4.20 (s, 3H,
CH3Nþ); 3.99 (s, 3H, CH3Nthiazol); 3.70 (s, 3H, CH3Nrhod); 2.30 (s, 3H,
CH3C4). HRMS (ESI) Mþ for C16H18N3OS2 calcd.: 332.08913; found:
332.0896. The ionization cluster (2Cþ, I2)þ is not seen. Anal. calcd. for
C16H18N3OIS2: C, 41.83; H, 3.95; N, 9.15; S, 13.96. Found: C, 41.56; H,
3.92; N, 9.54; S, 14.63.
(2Z,5E)-1-Methyl-2-[f3-methyl-5-(4-methyl-3-phenyl-1,3-thiazol-2-ylidene)-
4-oxo-1,3-thiazolidine-2-ylidenegmethyl] pyridinium p-Toluenesulfonate
(7bT). The condensation of 5b (2.53 g; 5 mmol) with 6T (1.39 g; 5 mmol)
gave in classical heating 7bT (2.03 g; 72%).
1
7bT: red powder; mp . 2608C. H NMR (200 MHz, DMSO-d6) d: 8.53
(d, 1H, J ¼ 6.4 Hz); 8.06 (t, 1H, J ¼ 7.5 Hz); 7.82 (d, 1H, J ¼ 6.9 Hz);
7.77–7.65 (m, 5Har); 7.49 (d, 2H, J ¼ 7.5 Hz); 7.33 (d, 2H, J ¼ 7.8 Hz);
7.27 (t, 1H, J ¼ 6.6 Hz); 6.93 (s, 1H, H5); 5.63 (s, 1H, CH55C2rhod); 4.00
(s, 3H, CH3Nþ); 2.53 (s, 3H, CH3Nrhod); 2.31 (s, 3H, CH3tos); 1.96 (s, 3H,
CH3C4). 13C NMR (50 MHz, DMSO-d6) d: 163.6 (C55O); 158.5
(C2thiazol); 152.3 (C2rhod); 148.8; 147.8; 146.8; 143.6; 137.1; 133.6;
132.2; 129.5; 127.8; 127.3; 125.4; 119.8; 116.0; 112.8; 112.3 (Car þ
Cpyriddine); 105.5 (C5thiazol); 82.5 (CH55C2rhod); 77.1 (C5rhod); 46.5
(CH3Nþ); 33.6 (CH3Nrhod); 20.7 (CH3tos); 13.6 (CH3C4). HRMS (ESI)
Mþ for C21H20N3OS2 calcd.: 394.10478; found: 394.1043. The ionization
clusters (2Cþ, Tos2)þ are found at m/z 959.
(2Z,5E)-1-Methyl-2-[f3-methyl-5-(4-methyl-3-phenyl-1,3-thiazol-2-ylidene)
-4-oxo-1,3-thiazolidine-2-ylidenegmethyl] pyridinium Iodide (7bI). The con-
densation of 5b (2.53 g; 5 mmol) with 6I (1.17 g; 5 mmol) gave in classical
heating 7bI (1.61 g; 62%).
7bI: red crystals; mp . 2608C. 1H NMR (200 MHz, DMSO-d6) d: 8.58
(d, 1H, J ¼ 6.6 Hz); 8.08 (t, 1H, J ¼ 8.1 Hz); 7.79–7.69 (m, 5Har); 7.33
(t, 1H, J ¼ 6.1 Hz); 7.15 (d, 1H, J ¼ 7.2 Hz); 6.92 (s, 1H, H5); 5.28
(s, CH55C2rhod); 4.00 (s, 3H, CH3Nþ); 2.54 (s, 3H, CH3Nrhod); 1.96
(s, 3H, CH3C4). HRMS (ESI) Mþ for C21H20N3OS2 calcd.: 394.10478;

4030
S. Kasmi-Mir et al.
found: 394.1043. The ionization cluster (2Cþ, I2)þ for C42H40N6O2IS4 calcd.:
915.11404; found: 915.1185. Anal. calcd. for C21H20N3OIS2: C, 48.37; H,
3.87; N, 8.06; S, 12.30. Found: C, 47.75; H, 3.82; N, 8.25; S,13.45.
(2Z,5E)-1-Methyl-2[f3-methyl-5-[4-methyl-3-(4-methylphenyl)-1,3-thiazol-
2-ylidene]-4-oxo-1,3-thiazolidine-2-ylidenegmethyl] pyridinium p-Toluene-
sulfonate (7cT). The condensation of 5c (2.60 g; 5 mmol) with 6T (1.39 g;
5 mmol) gave in classical heating 7cT (1.80 g; 60%).
7cT: red powder; mp ¼ 2348C. 1H NMR (200 MHz, DMSO-d6) d: 8.51
(d, 1H, J ¼ 6.2 Hz); 8.01 (t, 1H, J ¼ 7.9 Hz); 7.60 (d, 1H, J ¼ 6.1 Hz); 7.52
(m, 4Har); 7.40 (d, 2H, J ¼ 8.0 Hz); 7.23 (t, 1H, J ¼ 6.6 Hz); 7.09 (d, 2H,
J ¼ 7.6 Hz); 6.88 (s, 1H, H5); 5.59 (s, 1H, CH55C2); 3.97 (s, 3H, CH3Nþ);
3.35 (s, 3H, pCH3rhod); 2.52 (s, 3H, pCH3); 2.26 (s, 3H, CH3tos); 1.93
(s, 3H, CH3C4). 13C NMR (50 MHz, DMSO-d6) d: 164.1 (C55O); 157.1
(C2thiazol); 153.7 (C2rhod); 151.5; 146.6; 145.9; 142.4; 138.2; 133.0;
131.2; 130.9; 128.7; 126.0; 122.0; 118.1 (Car þ Cpyridine); 104.1
(C5thiazol); 83.5 (CH55C2rhod); 78.7 (C5rhod); 45.1 (CH3Nþ); 29.7
(CH3Nrhod); 20.8 (pCH3); 20.7 (pCH3tos); 13.78 (CH3C4). HRM (ESI)
Mþ for C22H22N3OS2 calcd.: 408.12043; found: 408.1209. The ionization
cluster (2Cþ, Tos2)þ is not seen.
(2Z,5E)-1-Methyl-2[f3-methyl-5-[4-methyl-3-(4-methylphenyl)-1,3-thiazol-
2-ylidene]-4-oxo-1,3-thiazolidine-2-ylidenegmethyl]pyridinium iodide (7cI).
The condensation of 5c (2.60 g; 5 mmol) with 6I (1.17 g; 5 mmol) gave in
classical heating, 7cI (1.44 g; 54%).
7cI: garnet red crystals; mp . 2608C. 1H NMR (200 MHz, DMSO-d6) d: 8.53
(d, 1H, J ¼ 6.7 Hz); 8.04 (t, 1H, J ¼ 7.2 Hz); 7.51 (m, 4H, J ¼ 7.9 Hz); 7.27
(t, 1H, J ¼ 7.1 Hz); 7.15 (d, 1H, J ¼ 8.4 Hz); 6.92 (s, 1H, H5); 5.62 (s, 1H,
CH55C2); 4.02 (s, 3H, CH3Nþ); 3.36 (s, 3H, pCH3rhod); 2.52 (s, 3H,
pCH3); 1.96 (s, 3H, CH3C4). HRMS (ESI) Mþ for C22H22N3OS2 calcd.:
408.12043; found: 408.1209. The ionization cluster (2Cþ, I2)þ for
C44H44N6O2IS4 calcd.: 943.14534; found: 943.1478.
(2Z,5E)-1-Methyl-2-[f3-(4-methylphenyl)-5-(3,4-dimethyl-1,3-thiazol-2-ylid
ene)-4-oxo-1,3-thiazolidine-2-ylidenegmethyl] pyridinium p-toluenesulfo-
nate (7dT). The condensation of 5d (2.60 g; 5 mmol) with 6T (1.39 g; 5 mmol)
gave in classical heating 7dT (2.10 g; 70%).
1
7dT: brick red powder; mp ¼ 2588C. H NMR (200 MHz, CDCl3) d: 8.58
(d, 1H, J ¼ 6.3 Hz); 8.19 (t, 1H, J ¼ 7.9 Hz); 7.98 (d, 1H, J ¼ 8.6 Hz); 7.76
(t, 1H, J ¼ 7.9 Hz); 7.38 (d, 2H, J ¼ 8.0 Hz); 7.20 (d, 2H, J ¼ 8.1 Hz; 7.08
(d, 2H, J ¼ 7.8 Hz); 7.01 (d, 2H, 6.7 Hz); 6.39 (s, 1H, H5); 5.27 (s, 1H,
CH55C2rhod); 4.02 (s, 3H, CH3Nþ); 3.70 (s, 3H, CH3Nthizol); 3.02 (s, 3H,

New Rhodacyanines
4031
CH3Nrhod); 2.40 (s, 3H, CH3tos); 2.29 (s, 3H, CH3C4). 13C NMR (50 MHz,
CDCl3) d: 164.7 (C55O); 159.9 (C2thiazol); 155.5 (C2rhod); 151.6; 145.6;
143.4; 142.5; 141.1; 138.9; 138.6; 131.9; 131.1; 128.4; 127.9; 125.9; 123.7;
117.9 (Car þ Cpyridine); 106.2 (C5thiazol); 83.2 (CH55C2rhod); 78.2
(C2rhod); 44.8 (CH3Nþ); 36.3 (CH3Nthiazol); 21.4 (pCH3rhod); 21.3
(pCH3tos); 14.7 (CH3C4). HRMS (ESI) Mþ for C22H22N3OS2 calcd.:
408.12043; found: 408.119. The ionization clusters (2Cþ, Tos2)þ is found
to be m/z 987.
(2Z,5E)-1-Methyl-2-[f3-(4-methylphenyl)-5-(3,4-dimethyl-1,3-thiazol-2-ylid
ene)-4-oxo-1,3-thiazolidine-2-ylidenegmethyl]pyridinium iodide (7dI). The
condensation of 5d (2.60 g; 5 mmol) with 6I (1.17 g; 5 mmol) gave in classical
heating 7dI (1.90 g; 72%).
1
7dI: garnet red crystals; mp ¼ 1928C. H NMR (200 MHz, CDCl3) d: 8.57
(d, 1H, J ¼ 6.5 Hz); 8.13 (t, 1H, J ¼ 7.9 Hz); 7.92 (d, 1H, J ¼ 8.5 Hz); 7.76
(d, 1H, J ¼ 8.0 Hz); 7.38 (d, 2H, J ¼ 8.1 Hz); 7.19 (d, 2H, J ¼ 8.2 Hz);
7.02 (t, 1H, J ¼ 6.6 Hz); 6.37 (s, 1H, H5); 528 (s, 1H, CH55C2rhod); 3.97
(s, 3H, CH3Nþ); 3.70 (s, 3H, CH3Nthiazol); 2.45 (s, 3H, CH3rhod); 2.30
(s, 3H, CH3C4). 13C NMR (50 MHz, CDCl3) d: 163.7 (C55O); 159.0
(C2thiazol); 154.5 (C2rhod); 150.5; 144.0; 142.3; 140.3; 139.0; 132.5;
128.5; 127.9; 117.4 (Car þ Cpyridine); 105.4 (C5thiazol); 83.9
(CH55C2rhod); 79.0 (C5rhod); 44.7 (CH3Nþ); 35.8 (CH3Nrhod); 21.3
(pCH3rhod); 14.6 (CH3C4). HRMS (ESI) for C22H22N3OS2 calcd.:
408.12043; found: 408.119. The ionization cluster (2Cþ, I2)þ for
C44H44N6O2IS4 calcd.: 943.14534; found: 943.1446.
(2Z,5E)-1-Methyl-2-[f3-(4-methylphenyl)-5-(4-methyl-3-phenyl-1,3-thiazol-
2-ylidene)-4-oxo-1,3-thiazolidine-2-ylidenegmethyl]pyridinium p-toluene-
sulfonate (7eT). The condensation of 5e (3.00 g; 5 mmol) with 6T (1.39 g;
5 mmol) gave in classical heating 7eT (2.00 g; 65%).
1
7eT: brown crystals; mp ¼ 2588C. H NMR (200 MHz, DMSO-d6) d: 8.46
(d, 1H, J ¼ 6.1 Hz); 8.06 (t, 1H, J ¼ 7.8 Hz); 7.73 (m, 5H); 7.47 (d, 2H,
J ¼ 8.0 Hz); 7.41 (d, 2H, J ¼ 8.2 Hz); 7.37 (d, 1H, J ¼ 7.9 Hz); 7.25
(m, 4Har); 7.12 (t, 1H, J ¼ 8.2 Hz); 6.91 (s, 1H, H5); 5.14 (s, 1H,
CH55C2rhod); 3.59 (s, 3H, CH3Nþ); 2.40 (s, 3H, pCH3); 2.28 (s, 3H,
CH3tos); 1.95 (s, 3H, CH3C4).13C NMR (50 MHz, DMSO-d6) d: 163.3
(C55O); 156.0 (C2thiazol); 153.2 (C2rhod); 151.2; 146.6; 140.0; 138.3; 138.1;
135.6; 135.1; 133.2; 132.1; 131.3; 130.9; 128.9; 128.7; 126.2; 122.0; 113.5;
112.6 (Car þ Cpyridine); 104.8 (C5thiazol); 84.9 (CH55C2thiazol); 76.5
(C2rhod); 44.5 (CH3Nþ); 20.8 (pCH3tos); 20.7 (pCH3rhod); 13.8 (CH3C4).
HRMS (ESI) Mþ for C27H24N3OS2 calcd.: 470.13608; found: 470.1358. The
ionization cluster (2Cþ, Tos2)þ is not seen. Anal. calcd. for C34H31N3O4S3:
C, 63.63; H, 4.87; N, 6.55; S, 14.99. Found: C, 63.29; H, 4.86; N, 6.64; S, 15.07.

4032
S. Kasmi-Mir et al.
(2Z,5E)-1-Methyl-2-[f3-(4-methylphenyl)-5-(4-methyl-3-phenyl-1,3-thiazol -
2-ylidene)-4-oxo-1,3-thiazolidine-2-ylidenegmethyl]pyridinium iodide (7eI).
The condensation of 5e (3.00 g; 5 mmol) with 6I (1.17 g; 5 mmol) gave in
classical heating 7eI (2.25 g; 75%).
1
7eI: brick red crystals; mp . 2608C. H NMR (200 MHz, CDCl3) d: 8.88
(d, 1H, J ¼ 6.2 Hz); 7.90 (t, 1H, J ¼ 8.0 Hz); 7.77 (t, 1H, J ¼ 8.0 Hz);
7.74–7.68 (m, 5Har); 7.42 (d, 2H, J ¼ 8.0 Hz); 7.28 (d, 2H, J ¼ 7.6 Hz);
7.20 (d, 1H, J ¼ 8.6 Hz); 6.4 (s, 1H, H5); 5.16 (s, 1H, CH55C2rhod); 3.7
(s, 3H, CH3Nþ); 2.3 (s, 3H, pCH3); 2.29 (s, 3H, CH3C4). 13C NMR
(50 MHz, CDCl3) d: 164.3 (C55O); 156.8 (C2thiazol); 154.5 (C2rhod);
150.6; 146.2; 143.6; 141.2; 137.2; 132.1; 130.1; 129.9; 128.7; 127.7; 121.8;
118.3 (Car þ Cpyridine); 104.5 (C5thizol); 84.4 (CH55C2rhod); 78.2
(C5rhod); 44.8 (CH3Nþ); 21.3 (pCH3); 14.4 (CH3C4). HRMS (ESI) Mþ for
C27H24N3OS2 calcd.: 470.13608; found: 470.1358. The ionization cluster
(2Cþ, I2)þ for C54H48N6O2IS4 calcd.: 1067.17664; found: 1067.1763. Anal.
calcd. for C27H24N3OIS2: C, 54.27; H, 4.05; N, 7.03; S, 10.73. Found: C,
53.92; H, 4.10; N, 7.27; S, 10.70.
(2Z,5E)-1-Methyl-2-[f3-(4-methylphenyl)-5-(4-methyl-3-(4-methylphenyl)-
1,3-thiazol-2-ylidene)-4-oxo-1,3-thiazolidine-2-ylidenegmethyl] pyridinium
p-toluenesulfonate (7fT). The condensation of 5f (3.00 g; 5 mmol) with 6T
(1.39 g; 5 mmol) gave in classical heating 7fT (2.34 g; 72%).
1
7fT: garnet red crystals; mp ¼ 2558C. H NMR (200 MHz, CDCl3) d: 8.9
(d, 1H, J ¼ 6.2 Hz); 7.8 (d, 2H, J ¼ 8.0 Hz); 7.7 (t, 1H, J ¼ 8.2 Hz); 7.5
(d, 2H, J ¼ 8.2 Hz); 7.38 (d, 2H, J ¼ 8.5 Hz); 7.30 (d, 2H, J ¼ 8.0 Hz);
7.25 (d, 1H, J ¼ 6.3 Hz); 7.17 (d, 2H, J ¼ 8.1 Hz); 7.13 (t, 1H, J ¼ 7.1 Hz);
6.45 (s, 1H, H5); 5.23 (s, 1H, CH55C2rhod); 3.85 (s, 3H, CH3Nþ); 2.62
(s, 3H, pCH3rhod); 2.48 (s, 3H, pCH3thiazol); 2.35 (s, 3H, CH3tos); 2.17
(s, 3H, CH3C4). 13C NMR (50 MHz, CDCl3) d: 164.3 (C55O); 156.5
(C2thiazol); 154.5 (C2rhod); 150.7; 146.5; 143.6; 142.2; 140.7; 140.4;
139.0; 137.3; 132.4; 132.1; 131.1; 130.9; 129.9; 128.4; 127.7; 126.0; 121.7;
118.2 (Car þ Cpyridine); 104.3 (C5thiazol); 84.3 (CH55C2rhod); 79.8
(C2rhod); 44.9 (CH3Nþ); 30.9 (pCH3thiazo); 21.4 (pCH3rhod); 21.3
(CH3tos); 14.4 (CH3C4). HRMS (ESI) Mþ for C28H26N3OS2 calcd.:
484.15173; found: 484.1520. The ionization cluser (2Cþ, Tos2)þ is not seen.
(2Z,5E)-1-Methyl-2-[f3-(4-methylphenyl)-5-(4-methyl-3-(4-methylphenyl) -
1,3-thiazol-2-ylidene)-4-oxo-1,3-thiazolidine-2-ylidenegmethyl]pyridinium
iodide (7fI). The condensation of 5f (3.00 g; 5 mmol) with 6I (1.17 g; 5 mmol)
gave in classical heating 7fI (2.24 g; 74%).
1
7fI: red crystals; mp ¼ 2168C. H NMR (200 MHz, CDCl3) d: 9.04 (d, 1H,
J ¼ 6.0 Hz); 7.7 (t, 1H, J ¼ 8.2 Hz); 7.57 (d, 1H, J ¼ 7.8 Hz); 7.30

New Rhodacyanines
4033
(d, 4Har); 7.20 (t, 1H, J ¼ 8.2 Hz); 7.15 (d, 4Har); 6. 47 (1H, H5); 5.21 (s, 1H,
CH55C2rhod); 3.84 (s, 3H, CH3Nþ); 2.48 (s, 3H, pCH3thiazol); 2.35 (s, 3H,
pCH3rhod); 2.04 (s, 3H, CH3C4). 13C NMR (50 MHz, CDCl3) d: 163.5
(C55O); 159.9 (C2thiazol); 154.3 (C4thiazol); 150.9; 145.5; 142.3; 140.9;
138.5; 137.5; 131.1; 129.9; 122.0; 117.8 (Car þ Cpyridine); 104.5
(C5thiazol); 84.2 (CH ¼ C2rhod); 79.5 (C2rhod); 45.3 (CH3Nþ); 31.0 (pCH3-
thiazol); 21.5 (pCH3rhod); 14.4 (CH3C4). HRMS (ESI) Mþ for C28H26N3OS2
calcd.: 484.15173; found: 484.1520. The ionization cluster (2Cþ, I2)þ for
C56H52N6O2IS4 calcd.: 1095.2079; found: 1095.2061.
ACKNOWLEDGMENT
We are grateful to the Accord Programme de Cooperation Mixte Inter Univer-
sitaire Algero-Franc¸ais No. 3 MDU 574. We thank Pierre Guenot, CRMPO,
and his group for mass spectrometry and elementary analyses.
REFERENCES
1. Kawakami, M.; Koya, K.; Ukai, T.; Tatsu, N.; Kegawa, I.; Ogawa, K.;
Shishido, T.; Chen, L. B. J. Med. Chem. 1997, 40, 3151.
2. Kawakami, M.; Koya, K.; Ukai, T.; Tatsuta, N.; Ikegawa, A.; Ogawa, K.;
Shishido, T.; Chen, L. B. J. Med. Chem. 1998, 41, 130.
3. Takasu, K.; Inoue, H.; Kim, H. S.; Suzuki, M.; Shishido, T.; Wataya, Y.; Ihara, M.
J. Med. Chem. 2002, 45, 995–998.
4. (a) Burder, A.; Swhney, S. N. J. Med. 1968, 11, 270; (b) Dash, B. C.;
Mahapatra, G. N. J. Proc. Inst. Chemists India 1967, 34, 178; (c) Yoshiro, U. Ann.
Rep. Res. Lab. 1968, 27, 112; (d) Tripathy, H.; Das, M. K.; Sahu, B.; Dash, B. C.;
Mahapatra, G. N. J. Indian Chem. So. 1973, 417–419; (e) Srivastava, K. S. L.
Alleg. PrKt. Chem. 1968, 19, 398; (f) Singa, J. M.; Tripathy, B. N. J. Indian
Chem. Soc. 1970, 47, 23; (g) Buroi, N. P.; SaintRuf, G.; Perche, J. C.;
Bourgeade, J. C. Chim. Ther. 1968, 3, 110; (h) Garmaise, D. L.; Chambers, C. H.;
Mecreal, R. C. J. Med. Chem. 1968, 11, 1205.
5. (a) Foye, W. O.; Thomas, L. L.; David, A.; Williams, B. I. Principles of Medicinal
Chemistry, 4th edn.; Waverly: New Delhi, 1995; (b) Pawar, N. S.; Dalal, D. S;
Shimpi, S. R; Mahulikar, P. P.; European Journal of Pharmaceutical Sciences,
2004, 21, 115.
6. (a) Kadam, S. S.; Mahadik, K. R.; Bothhara, K. G. Principles of Medicinal
Chemistry; Vols. I and II, 1997; (b) Patil, S. G.; Patil, M. G.; Mendki, P. S;
Maheshwari, V. L; Khothari, R. M.; Pestology, 2000, 25, 37.
7. (a) Roussel, C.; Gallo, R.; Chanon, M.; Metzger, J. Bull. Soc. Chim. Fr. 1971,
1902; (b) Datta, K. C.; Roussel, C.; Metzger, J. Bull. Soc. Chim. Fr. 1974, 2135;
(c) Roussel, C.; Babadjamian, A.; Chanon, M.; Metzger, J. Bull. Soc. Chim. Fr.
1971, 87; (d) Roussel, C.; Adjimi, M.; Chemlal, A.; Djafri, A. J. Org. Chem.
1988, 56, 5076.

4034
S. Kasmi-Mir et al.
8. (a) Brooker, L. G. S.; Keyes, G. H.; Williams, W. W. J. Am. Chem. Soc. 1942, 6,
199; (b) Brooker, L. G. S.; Keyes, G. H. J. Am. Chem. Soc. 1937, 59, 74.
9. (a) Loupy, A.; Petit, A.; Texier-Boullet, F.; Jacqualt, M. D. Synthesis 1998, 1213;
(b) Kappe, C. O. Angew. Chem. Int. Ed. 2004, 43, 6250; (c) Bougrin, K.;
Loupy, A.; Soufiaoui, J. Photochem. Photobiol. C. Photochemistry Rer. 2005, 6,
¨
139; (d) Microwave-Assisted Organic Synthesis; Lidstrom, P. and
Thierney, J. P., Eds.; Blackwell: Oxford, 2005; (e) Loupy, A. Ed. Microwaves
in Organic Synthesis; Wiley-VCH: Weinheim, 2006.
10. (a) Singh, S. P.; Parmar, S. S.; Raman, K.; Stenherb, V. I. Chem. Phar. Bull. 1981,
81, 175; (b) Brown, F. C. Chem. Rev. 1961, 61, 463.