Synthesis of new hetarylazoindole dyes from some 2-aminothiazole derivatives

Article abstract of DOI:10.1134/S1070428008040209

A new series of heterocyclic disperse dyes were prepared by diazotization of some 2-aminothiazole derivatives and subsequent coupling with indole compounds. The dyes were characterized by UV-Vis, FT-IR, ¹H NMR, and mass spectra (LC-MS). Solvent effects on their visible absorption spectra were estimated. The color of the dyes is discussed with respect to the substituent therein. The effects of acids and bases on the visible absorption maxima of the dyes are also reported. Replacement of methyl group in the 4-position of the thiazole ring by phenyl group leads to red shift of the absorption maximum due to π-electron-donating properties of the phenyl group, while weak electron-withdrawing chlorine or bromine atom in the para-position of the phenyl group in the 2-amino-4-phenylthiazole fragment induce a small blue shift relative to 2-amino-4-phenylthiazole derivatives. Introduction of an electron-withdrawing 4-nitrophenylsulfonyl group into the thiazole ring produces bathochromic shift of the absorption maximum in all solvents.

Full text of DOI:10.1134/S1070428008040209

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2008, Vol. 44, No. 4, pp. 587–594. © Pleiades Publishing, Ltd., 2008.
Published in Russian in Zhurnal Organicheskoi Khimii, 2008, Vol. 44, No. 4, pp. 592–599.
Synthesis of New Hetarylazoindole Dyes from Some
2-Aminothiazole Derivatives*
A. Saylam, Z. Seferoglu, and N. Ertan
Gazi Üniversitesi, Fen-Edebiyat Fakültesi, Kimya Bölumü, 06500 Teknikokullar, Ankara, Turkiye
phone: +(90312)2323588; fax: +(90312)2323226; e-mail: znseferoglu@yahoo.com; znseferoglu@gazi.edu.tr
Received June 26, 2006
Abstract—A new series of heterocyclic disperse dyes were prepared by diazotization of some 2-aminothiazole
derivatives and subsequent coupling with indole compounds. The dyes were characterized by UV-Vis, FT-IR,
1H NMR, and mass spectra (LC–MS). Solvent effects on their visible absorption spectra were estimated. The
color of the dyes is discussed with respect to the substituent therein. The effects of acids and bases on the
visible absorption maxima of the dyes are also reported. Replacement of methyl group in the 4-position of the
thiazole ring by phenyl group leads to red shift of the absorption maximum due to π-electron-donating
properties of the phenyl group, while weak electron-withdrawing chlorine or bromine atom in the para-position
of the phenyl group in the 2-amino-4-phenylthiazole fragment induce a small blue shift relative to 2-amino-4-
phenylthiazole derivatives. Introduction of an electron-withdrawing 4-nitrophenylsulfonyl group into the
thiazole ring produces bathochromic shift of the absorption maximum in all solvents.
DOI: 10.1134/S1070428008040209
Disperse dyes are colorants that are poorly soluble
in water and are suitable for dyeing and printing
hydrophobic fibers and fabrics in the disperse colloidal
form [1]. Azo dyes constitute the largest group of
disperse dyes. The use of heterocyclic azo and diazo
components in the synthesis of disperse azo dyes is
well-established, and the resultant dyes exhibit good
tinctorial strength and brighter dyeing than those
derived from aniline-based components [2–4]. In the
recent years many research teams reported on the syn-
thesis of disperse azo dyes from heterocyclic amines
and various heterocyclic coupling components and
their applications for dyeing polyester fabrics [5, 6]. In
addition, Wang and co-worker [7] described the syn-
thesis of azo dyes from 2-amino-4-(p-substituted
phenyl)thiazole derivatives and various heterocyclic
coupling components and studied their spectroscopic
properties with respect to substituent and solvent po-
larity. On the other hand, the use of amino-substituted
thiazoles as very electronegative diazo component
produces a pronounced bathochromic shift as com-
pared to the corresponding benzoid compounds [8–12].
Moreover, some 2-aminothiazole derivatives have
been used as a π-bridged chromophore for the prepara-
Scheme 1.
R3
R3
N
N
R2
N
+
N2 HSO4
N
R1
N
R4
S
N
R4
S
R1
R2
I–XVIII
I, R1 = R4 = H, R2 = R3 = Me; II, R1 = R4 = H, R2 = Ph, R3 = Me; III, R1 = R3 = Me, R2 = Ph, R4 = H; IV, R1 = R4 = H, R2 = Me, R3 =
EtOCOCH2; V, R1 = R4 = H, R2 = Ph, R3 = EtOCOCH2; VI, R1 = Me, R2 = Ph, R3 = EtOCOCH2, R4 = H; VII, R1 = R4 = H, R2 = Me,
R3 = Ph; VIII, R1 = R4 = H, R2 = R3 = Ph; IX, R1 = Me, R2 = R3 = Ph, R4 = H; X, R1 = R4 = H, R2 = Me, R3 = 4-ClC6H4; XI, R1 =
R4 = H, R2 = Ph, R3 = 4-ClC6H4; XII, R1 = Me, R2 = Ph, R3 = 4-ClC6H4, R4 = H; XIII, R1 = R4 = H, R2 = Me, R3 = 4-BrC6H4;
XIV, R1 = R4 = H, R2 = Ph, R3 = 4-BrC6H4; XV, R1 = Me, R2 = Ph, R3 = 4-BrC6H4, R4 = H; XVI, R1 = R3 = H, R2 = Me, R4 =
4-O2NC6H4SO2; XVII, R1 = R3 = H, R2 = Me, R4 = 4-O2NC6H4SO2; XVIII, R1 = Me, R2 = Ph, R3 = H, R4 = 4-O2NC6H4SO2.
* The text was submitted by the authors in English.
587

SAYLAM et al.
588
Scheme 2.
Me
Me
Me
–H+
H+
N
N
N
N
N
N
N
N
N
N
N
N
S
H
S
S
··
H
Me
Me
Me
A
B
C
tion of polymers with nonlinear optical properties [13].
Some thiazole derivatives are important from the phar-
maceutical viewpoint. Heterocyclic systems containing
a 1,3-thiazole ring exhibit a wide spectrum of bio-
logical activity, including antiviral and antifungal.
1,3-Thiazole ring was identified as a base structural
unit of a number of biologically active natural products
[14–16] and pharmacologically active compounds
[17, 18]. Biological activity of thiazole derivatives
originates mainly from their structural, electronic, and
spectroscopic similarity to imidazole entities of
proteins [19–21].
The IR spectra of I, II, IV, V, VII, VIII, X, XI,
XIII, XIV, XVI, and XVII in KBr contained a broad
absorption band in the region 3442–3210 cm–1 due to
indole NH group. No such band was present in the IR
spectra of N-methyl-2-phenylindole derivatives III,
VI, IX, XII, XV, and XVIII. The spectra of all azo
dyes I–XVIII displayed absorption bands in the
regions 3082–3050 (C–Harom) and 2973–2870 cm–1
(C–Haliph). In the 1H NMR spectra of XVI and XVII in
DMSO-d6–CDCl3 we observed a signal at δ 12.54–
12.51 ppm from the NH proton. The other dyes (except
for those derived from 1-methyl-2-phenyl-1H-indole)
showed the NH signal at δ 13.10–11.50 ppm. These
results suggest that the azo tautomer of all dyes predo-
minates in DMSO and DMSO–chloroform mixture.
Many patents and papers described the synthesis
and some properties of carbocyclic azo indole com-
pounds [22–27], but only a few data are available on
hetarylazo indole derivatives from patent literature
[28–38]. We previously synthesized some hetarylazo
indole dyes and evaluated their spectroscopic prop-
erties [39]. We now report on the synthesis of six
series of 3-(1,3-thiazol-2-ylazo)indole derivatives I–
XVIII using 2-methyl-1H-indole, 2-phenyl-1H-indole,
and 1-methyl-2-phenyl-1H-indole as coupling compo-
nents. The visible absorption spectra of these com-
pounds in various solvents were discussed. In addition,
spectroscopic properties of the azo dyes were exam-
ined with respect to the effects of substituents present
in the thiazole and indole rings.
The UV-Vis absorption spectra of hetarylazo indole
dyes I–XVIII were measured in various solvents
(Table 1) in the λ range from 300 to 800 nm at a con-
centration of 10–6 to 10–8 M. Almost all compounds
displayed only one absorption band, indicating the
presence of a single tautomer (azo). As follows from
the data in Table 1, introduction of strongly electron-
withdrawing 4-nitrophenylsulfonyl group into the thia-
zole ring (compounds XVI and XVII) leads to dis-
placement of tautomeric equilibrium toward the hydra-
zone structure in DMSO and DMF. The same results
were obtained for dyes II, V, VIII, XI, and XIV in
DMSO and DMF. The absorption maximum of the
hydrazone tautomer is located at longer wavelengths.
These data are in good agreement with our previous
results according to which hetarylazopyrazolone and
hetarylazopyridone dyes in DMSO and DMF exist pre-
ferentially in the hydrazone form [11, 12].
Hetarylazo indole dyes I–XVIII were prepared by
diazo coupling of 2-methyl-, 2-phenyl-, and 1-methyl-
2-phenyl-1H-indoles with diazotized 4-methyl-1,3-thi-
azol-2-amine, ethyl 2-amino-1,3-thiazol-4-ylacetate,
4-phenyl-1,3-thiazol-2-amine, 4-(4-chlorophenyl)-1,3-
thiazol-2-amine, 4-(4-bromophenyl)-1,3-thiazol-2-
amine, and 5-(4-nitrophenylsulfonyl)-1,3-thiazol-2-
amine in nitrosyl sulfuric acid (Scheme 1). The struc-
ture of the resulting dyes was confirmed by the FT-IR,
1H NMR, and mass spectra. Dyes I, IV, VII, X,
XIII, and XVI prepared from 2-methyl-1H-indole and
compounds II, V, VIII, XI, XIV, and XVII obtained
from 2-phenyl-1H-indole may exist as two tautomers,
azo A and hydrazone B, as shown in Scheme 2. De-
protonation of both tautomers could lead to common
anion C.
The electronic absorption spectrum of dye XVI
(Fig. 1) shows one or two isosbestic points at λ 497,
499, and 505 nm. The absorption maximum of XVI in
acetic acid is located at the middle of these isosbestic
points. This means that azo–hydrazone equilibrium
exists in various solvents. On the other hand, tauto-
meric equilibria of dye XVI were observed in various
solvent mixtures, and regular relations with dielectric
constants of the solvents were revealed. Only the azo
tautomer was identified in 100% chloroform, while
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 44 No. 4 2008

SYNTHESIS OF NEW HETARYLAZOINDOLE DYES
Table 1. Solvent effect on the absorption maxima (λ, nm) of dyes I–XVIII
589
Compound no.
DMSO
DMF
Acetonitrile
Methanol
Acetic acid
Chloroform
I
469
515
461
484
512
461
497
524
482
486
513
473
480
521
474
531
550
502
469
513
456
485
512
455
496
522
478
487
507
469
491
519
469
523
551
500
417
469
450
439
467
451
467
499
472
451
469
464
452
484
464
478
503
492
442
466
454
442
466
453
461
484
473
452
477
467
452
476
406
480
504
474
476
476
469
448
469
461
460
485
476
453
477
469
454
475
467
494
521
491
419
464
450
418
453
454
458
480
473
447
473
467
448
469
466
479
504
481
II
III
IV
V
VI
VII
VIII
IX
X
XI
XII
XIII
XIV
XIV
XVI
XVII
XVIII
100% DMSO contained only the hydrazone tautomer.
The absorption maximum shifts to the red region upon
addition of a polar solvent (such as DMSO) to a solu-
tion of XVI in chloroform (Fig. 1). The dyes generally
displayed a single main absorption peak without
a shoulder in all solvents. The visible absorption spec-
tra of the dyes were found to exhibit a strong solvent
dependence; however, no regular variation with the
solvent polarity was observed, except for compound
VII. In going from DMSO (ε = 46.45) to less polar
DMF (ε = 36.71), acetonitrile (ε = 35.94), methanol
(ε = 32.66), acetic acid (ε = 6.17), and chloroform (ε =
4.81)), the absorption maximum shifts blue. Excep-
tions were dyes XIII (Δλmax = 32 nm for DMSO, 43 nm
for DMF, 6 nm for acetic acid, and 4 nm for methanol
relative to CHCl3), XVI (Δλmax = 52 nm for DMSO,
44 nm for DMF, 15 nm for acetic acid, and 1 nm for
methanol), and XI (Δλmax = 40 nm for DMSO, 34 nm
for DMF, 4 nm for acetonitrile, 4 nm for acetic acid,
and 4 nm for methanol) (Figs. 2, 3).
was compound IV. The Δλmax values for dye V relative
to II were 3 nm in DMSO, 7 nm in acetic acid, and
1 nm in chloroform. The presence of an electron-
donating phenyl group in the 4-position of the thiazole
ring gives rise to a bathochromic shift relative to
the corresponding 4-methylthiazole derivatives in all
solvents, except for dye VII in acetic acid: VII,
1.4
5
1.2
1
4
1.0
0.8
0.6
2
3
0.4
0.2
0.0
Substituent effect the on absorption maxima of het-
arylazo indole dyes was also examined. Introduction of
an electron-withdrawing CH2COOC2H5 group instead
of methyl into the 4-position of the thiazole ring
(compounds IV–VI) induced a slight hypsochromic
shift relative to dyes I–III in all solvents; an exception
300
400
500
600
700
λ, nm
Fig. 1. Electronic absorption spectra of 2-methyl-3-[5-(4-ni-
trophenylsulfonyl)-1,3-thiazol-2-yldiazenyl]-1H-indole
(XVI) in (1) DMSO, (2) DMSO–CHCl3 (80:20), (3) DMSO–
CHCl3 (50:50), (4) DMSO–CHCl3 (20:80), and (5) CHCl3.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 44 No. 4 2008

SAYLAM et al.
Δλmax(XV/IX) = 7 nm in chloroform). These results
590
1.4
6
3
are in agreement with the data reported for 4-substi-
tuted thiazolylazopyrazolone and thiazolylazopyridone
derivatives [7]. On the other hand, introduction of
an electron-withdrawing 4-nitrophenylsulfonyl group
into the 5-position of the thiazole ring resulted in
a bathochromic shift of the absorption maximum in
all solvents: Δλmax(XVI/I) = 62 nm in DMSO;
Δλmax(XVII/XI) = 34 nm in acetonitrile and 60 nm in
chloroform; Δλmax(XVIII/IX) = 22 nm in DMF. Anal-
ogous patterns were observed previously for substi-
tuted thiazolylazo dyes [4]. The presence of a phenyl
group in the 2-positon of the indole ring induces
a bathochromic shift relative to 2-methylindole deriva-
tives: Δλmax(II/I) = 46 nm in DMSO, 52 nm in acetoni-
trile, and 45 nm in chloroform; Δλmax(XI/X) = 20 nm
in DMF, 25 nm in methanol, 24 nm in acetic acid.
5
1.2
1.0
0.8
0.6
0.4
0.2
0.0
2
1
4
300
400
500
600 λ, nm
Fig. 2. Electronic absorption spectra of 2-methyl-3-[5-(4-ni-
trophenylsulfonyl)-1,3-thiazol-2-yldiazenyl]-1H-indole (XVI)
in (1) acetic acid, (2) acetonitrile, (3) dimethylformamide,
(4) dimethyl sulfoxide, (5) chloroform, and (6) methanol.
The effect of the acidity of the medium on the elec-
tronic absorption spectra of helarylazo indole dyes is
illustrated by the data in Table 2 and Fig. 4. Addition
of 0.1 M hydrochloric acid to solutions of compounds
I–XVIII (except for dye XVII) in methanol induces
a bathochromic shift of the absorption maximum rela-
tive to its position in pure methanol: III, Δλmax = 1 nm;
V, Δλmax = 55 nm; XIII, Δλmax = 49 nm). These data
indicate that dyes I–XVI and XVIII undergo protona-
tion. However, analogous effect (red shift) was ob-
served upon addition of 0.1 M KOH to solutions of
1.6
3
1.4
1
4
2
5
1.2
1.0
6
0.8
0.6
0.4
0.2
0.0
the dyes in methanol: V, Δλmax = 16 nm; XI, Δλmax
=
22 nm; XVI, Δλmax = 33 nm. Presumably, dyes I–
XVIII exist in the anionic form (Scheme 2) in 0.1 M
methanolic alkali. In contrast, addition of a small
amount of piperidine to solutions of the dyes in
DMSO, DMF, and CHCl3 did not produce any signif-
icant variation of the λmax values.
300
400
500
600 λ, nm
EXPERIMENTAL
Fig. 3. Electronic absorption spectra of 3-[4-(4-chloro-
phenyl)-1,3-thiazol-2-yldiazenyl]-2-phenyl-1H-indole (XI)
in (1) acetic acid, (2) acetonitrile, (3) dimethylformamide,
(4) dimethyl sulfoxide, (5) chloroform, and (6) methanol.
All initial compounds used in the synthesis of dyes
I–XVIII were purchased from Aldrich Chemical Com-
pany and were used without additional purification.
The solvent used were of spectroscopic grade. The IR
spectra were recorded in KBr on a Mattson 1000
Δλmax(VII/I) = 28 nm in DMSO; VIII, Δλmax(VIII/II) =
30 nm in acetonitrile; IX, Δλmax(IX/III) = 23 nm in
methanol). Weak electron-withdrawing chloro and
bromo substituents in the para position of the phenyl
group on the thiazole ring produced hypsochromic
shift in all solvents: Δλmax(X/VII) = 11 nm in DMSO;
Δλmax(XI/VIII) = 30 nm in acetonitrile; Δλmax(XII/IX) =
6 nm in chloroform; Δλmax(XIII/VII) = 17 nm in
DMSO; Δλmax(XIV/VIII) = 8 nm in methanol;
1
FT-IR spectrophotometer. The H NMR spectra were
obtained on a Bruker Spectrospin Avance DTX 400
Ultra-Shield instrument from solutions in DMSO-d6
and CDCl3 using tetramethylsilane as internal refer-
ence. The electronic absorption spectra were measured
on an Analytika Jena UV-200 spectrophotometer.
Analysis by liquid chromatography–mass spectrometry
(LC–MS) was performed on an Agilent 1100 MSD
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 44 No. 4 2008

SYNTHESIS OF NEW HETARYLAZOINDOLE DYES
591
1.8
1.6
1.4
1.2
2
1.2
6
1
1.0
3
5
4
0.8
1.0
0.8
0.6
0.4
0.2
0.0
0.6
0.4
0.2
0.0
300
400
500
600 λ, nm
300
400
500
600
λ, nm
Fig. 4. Electronic absorption spectra of 3-[4-(4-chlorophenyl)-1,3-thiazol-2-yldiazenyl]-2-phenyl-1H-indole (XI) in acidic and
basic solutions: (1) DMSO, (2) DMSO+piperidine, (3) acetic acid, (4) methanol, (5) methanol+0.1 M HCl, and (6) methanol+
0.1 M KOH.
instrument at the TUBITAK ATAL Laboratories
(Center of Science and Technology Research of
Turkey). All melting points were uncorrected.
(C–Haliph); 1548 (C=C). 1H NMR spectrum (DMSO-d6),
δ, ppm: 12.50 br.s (NH), 8.92 s (1H), 8.53 m (1H),
7.20–7.30 m (2H), 6.80 s (1H), 2.98 s (3H), 2.65 s
(3H). Mass spectrum, m/z (Irel, %): 257 (100) [M + 1]+,
158 (33.0), 130 (13.3).
General procedure for the synthesis of thiazolyl-
azo indole dyes I–XVIII. The corresponding substi-
tuted 2-amino-1,3-thiazole, 2 mmol, was dissolved in
6.0 ml of a hot 2:1 glacial acetic acid–propionic acid
mixture, and the solution was quickly cooled to –5°C
using an ice–salt bath. The solution was then added in
portions over a period of 30 min under stirring to
a cold solution of nitrosyl sulfuric acid (prepared from
0.15 g of sodium nitrite and 3 ml of concentrated
sulfuric acid at 70°C). The mixture was stirred for 2 h
at 0°C, excess nitrous acid was decomposed by adding
urea, and the resulting diazonium salt solution was
cooled in an ice–salt bath and added dropwise under
stirring to a solution of 2 mmol of the corresponding
substituted indole in 8 ml of a 3:1 acetic acid–propi-
onic acid mixture, preliminarily cooled in an ice–salt
bath. The mixture was stirred for 2 h at 0–5°C, main-
taining the pH value at 4 to 6 by simultaneous addition
of a saturated sodium carbonate solution. The mixture
was then stirred for 24 h at room temperature, and the
precipitate was filtered off, washed with cold water,
dried, and recrystallized from ethanol.
3-(4-Methyl-1,3-thiazol-2-yldiazenyl)-2-phenyl-
1H-indole (II) was synthesized from 4-methyl-1,3-
thiazol-2-amine and 2-phenyl-1H-indole. Yield 0.51 g
(80%), red–brown crystals, mp 158 °C. IR spectrum,
ν, cm–1: 3442 (NH); 3050 (C–Harom); 2960, 2877
(C–Haliph); 1490 (C=C). 1H NMR spectrum (DMSO-d6),
δ, ppm: 11.50 br.s (NH), 8.40 d (1H), 8.10 d (1H),
7.90 d (2H), 7.65–7.30 m (3H), 7.10 m (1H), 7.00 m
(1H), 6.90 s (1H), 2.50 s (3H). Mass spectrum, m/z
(Irel, %): 319 (100) [M + 1]+, 220 (91.4), 192 (47.8).
1-Methyl-3-(4-Methyl-1,3-thiazol-2-yldiazenyl)-
2-phenyl-1H-indole (III) was synthesized from
4-methyl-1,3-thiazol-2-amine and 1-methyl-2-phenyl-
1H-indole. Yield 0.56 g (85%), red crystals,
mp 116°C. IR spectrum, ν, cm–1: 3050 (C–Harom),
2947 (C–Haliph), 1471 (C=C). 1H NMR spectrum
(DMSO-d6), δ, ppm: 8.40 d (1H), 7.73 m (2H), 7.45–
7.61 m (4H), 7.20 m (1H), 7.10 m (1H), 6.60 s (1H),
3.88 s (3H), 2.40 s (3H). Mass spectrum, m/z (Irel, %):
333 (100) [M + 1]+, 234 (65.9), 206 (29.0).
2-Methyl-3-(4-methyl-1,3-thiazol-2-yldiazenyl)-
1H-indole (I) was synthesized from 4-methyl-1,3-
thiazol-2-amine and 2-methyl-1H-indole. Yield 0.45 g
(87%), brown crystals, mp 238°C. IR spectrum, ν,
cm–1: 3397 (NH); 3056 (C–Harom); 2960, 2870
Ethyl [2-(2-methyl-1H-indol-3-yldiazenyl)-1,3-
thiazol-4-yl]acetate (IV) was synthesized from ethyl
2-amino-1,3-thiazol-4-ylacetate and 2-methyl-1H-
indole. Yield 0.57 g (87%), orange crystals, mp 183°C.
IR spectrum, ν, cm–1: 3275 (NH), 3082 (C–Harom),
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 44 No. 4 2008

SAYLAM et al.
592
Table 2. Absorption maxima of dyes I–XVIII in acidic and basic solutions
λ
max, nm
Compound
no.
DMSO +
piperidine
DMF +
piperidine
MeOH + MeOH +
CHCl3 +
piperidine
DMSO
DMF
MeOH
CHCl3
KOH
HCl
I
469
515
461
484
512
461
497
524
482
486
513
473
480
521
474
531
550
502
469
516
461
490
515
460
499
524
482
495
520
473
498
521
473
532
550
504
469
513
456
485
512
455
496
522
478
487
507
469
491
519
469
523
551
500
483
514
456
487
513
455
497
523
477
492
520
469
493
519
469
531
551
502
442
466
454
442
466
453
461
484
473
452
477
467
452
476
466
480
504
474
451
485
453
453
482
453
484
510
473
468
499
467
467
498
467
513
533
475
496
522
512
493
521
510
479
495
492
498
511
509
501
520
499
489
505
500
419
464
450
418
453
454
458
480
473
447
473
467
448
469
466
479
504
481
422
461
448
423
462
448
460
482
473
452
474
466
453
473
466
490
516
484
II
III
IV
V
VI
VII
VIII
IX
X
XI
XII
XIII
XIV
XIV
XVI
XVII
XVIII
1
2979 (C–Haliph), 1708 (C=O), 1472 (C=C). H NMR
spectrum (DMSO-d6), δ, ppm: 12.50 br.s (NH), 8.20 d
(1H), 7.40 d (1H), 7.30 s (1H), 7.20–7.10 m (2H),
4.05 q (2H), 3.75 s (2H), 2.65 s (3H), 1.15 s (3H).
Mass spectrum, m/z (Irel, %): 329 (62.2) [M + 1]+, 172
(31.2), 158 (100).
(1H), 4.10 q (2H), 3.90 s (3H), 3.80 s (2H), 1.20 t
(3H). Mass spectrum, m/z (Irel, %): 405 (100) [M + 1]+,
234 (30.3), 206 (7.7).
2-Methyl-3-(4-phenyl-1,3-thiazol-2-yldiazenyl)-
1H-indole (VII) was synthesized from 4-phenyl-1,3-
thiazol-2-amine and 2-methyl-1H-indole. Yield 0.50 g
(79%), red crystals, mp 185°C. IR spectrum, ν, cm–1:
3275 (NH); 3056 (C–Harom); 2921, 2870 (C–Haliph);
Ethyl [2-(2-phenyl-1H-indol-3-yldiazenyl)-1,3-
thiazol-4-yl]acetate (V) was synthesized from ethyl
2-amino-1,3-thiazol-4-ylacetate and 2-phenyl-1H-in-
dole. Yield 0.68 g (87%), red crystals, mp 188°C. IR
spectrum, ν, cm–1: 3288 (NH); 3056 (C–Harom); 2979,
1
1464 (C=C). H NMR spectrum (DMSO-d6), δ, ppm:
12.80 br.s (NH), 8.25 m (1H), 8.00 m (2H), 7.55 m
(2H), 7.45 m (3H), 7.30 m (2H), 2.80 s (3H). Mass
spectrum, m/z (Irel, %): 319 (100) [M + 1]+, 158 (21.7),
130(6.0).
1
2870 (C–Haliph); 1715 (C=O); 1522 (C=C). H NMR
spectrum (DMSO-d6), δ, ppm: 12.80 br.s (NH), 8.30 d
(1H), 8.00 d (2H), 7.40–7.60 m (4H), 7.30 s (1H),
7.20 m (2H), 4.10 q (2H), 1.20 t (3H). Mass spectrum,
m/z (Irel, %): 391 (100) [M + 1]+, 220 (28.8), 192 (6.8).
2-Phenyl-3-(4-phenyl-1,3-thiazol-2-yldiazenyl)-
1H-indole (VIII) was synthesized from 4-phenyl-1,3-
thiazol-2-amine and 2-phenyl-1H-indole. Yield 0.62 g
(81%), claret red crystals, mp 127°C. IR spectrum, ν,
cm–1: 3416 (NH), 3063 (C–Harom), 1458 (C=C).
1H NMR spectrum (DMSO-d6), δ, ppm: 13.10 br.s
(NH), 8.40 d (1H), 8.12 d (1H), 7.98 d (1H), 7.50–
7.40 m (12H). Mass spectrum, m/z (Irel, %): 381 (100)
[M + 1]+, 220 (14.7), 192 (5.9).
Ethyl [2-(1-methyl-2-phenyl-1H-indol-3-yldi-
azenyl)-1,3-thiazol-4-yl]acetate (VI) was synthesized
from ethyl 2-amino-1,3-thiazol-4-ylacetate and 1-meth-
yl-2-phenyl-1H-indole. Yield 0.69 g (86%), red crys-
tals, mp 178°C. IR spectrum, ν, cm–1: 3063 (C–Harom);
2940, 2896 (C–Haliph); 1727 (C=O); 1529 (C=C).
1H NMR spectrum (DMSO-d6), δ, ppm: 8.40 d (1H),
7.75 d (3H), 7.63 d (3H), 7.40–7.50 m (2H), 7.30 s
1-Methyl-2-phenyl-3-(4-phenyl-1,3-thiazol-2-yl-
diazenyl)-1H-indole (IX) was synthesized from
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 44 No. 4 2008

SYNTHESIS OF NEW HETARYLAZOINDOLE DYES
593
4-phenyl-1,3-thiazol-2-amine and 1-methyl-2-phenyl-
1H-indole. Yield 0.67 g (85%), red crystals,
mp 230°C. IR spectrum, ν, cm–1: 3056 (C–Harom), 2935
(C–Haliph), 1471 (C=C). 1H NMR spectrum (DMSO-d6),
δ, ppm: 8.40 d (1H), 8.00 d (1H), 7.42–7.81 m (10H),
7.20 s (1H), 7.10 s (1H), 6.60 s (1H), 3.90 s (3H).
Mass spectrum, m/z (Irel, %): 395 (100) [M + 1]+, 234
(55.5), 220 (3.5), 206 (17.0).
4-(4-bromophenyl)-1,3-thiazol-2-amine and 2-phenyl-
1H-indole. Yield 0.77 g (84%), light claret red crystals,
mp 166°C. IR spectrum, ν, cm–1: 3210 (NH), 3050
(C–Harom), 1458 (C=C). 1H NMR spectrum (DMSO-d6),
δ, ppm: 8.50 d (1H), 8.20 d (1H), 8.10 s (1H), 8.00 d
(1H), 7.50–7.70 m (3H), 7.40 m (2H). Mass spectrum,
m/z (Irel, %): 459 (100) [M]+, 220 (37.4), 192 (16.0).
3-[4-(4-Bromophenyl)-1,3-thiazol-2-yldiazenyl]-
1-methyl-2-phenyl-1H-indole (XV) was synthesized
from 4-(4-bromophenyl)-1,3-thiazol-2-amine and
1-methyl-2-phenyl-1H-indole. Yield 0.79 g (83%),
light orange crystals, mp 240°C. IR spectrum, ν, cm–1:
3056 (C–Harom), 2935 (C–Haliph), 1471 (C=C). 1H NMR
spectrum (DMSO-d6), δ, ppm: 8.50 d (1H), 8.05 s
(1H), 8.00 d (2H), 7.80 d (2H), 7.60–7.70 m (5H),
7.50 m (2H), 3.90 s (3H). Mass spectrum, m/z (Irel, %):
475 (100) [M + 2]+, 473 (96.0). 234 (91.6), 206 (49.2),
158 (21.3).
3-[4-(4-Chlorophenyl)-1,3-thiazol-2-yldiazenyl]-
2-methyl-1H-indole (X) was synthesized from
4-(4-chlorophenyl)-1,3-thiazol-2-amine and 2-methyl-
1H-indole. Yield 0.56 g (79%), orange crystals,
mp 220°C. IR spectrum, ν, cm–1: 3281 (NH), 3070
1
(C–Harom), 2921 (C–Haliph), 1458 (C=C). H NMR
spectrum (DMSO-d6), δ, ppm: 8.30 m (1H), 8.05 d
(2H), 8.00 s (1H), 7.53 d (2H), 7.45 m (1H), 7.30 m
(2H), 2.75 s (3H). Mass spectrum, m/z (Irel, %): 353
(100) [M + 1]+, 196 (11.8), 158 (40.8).
3-[4-(4-Chlorophenyl)-1,3-thiazol-2-yldiazenyl]-
2-phenyl-1H-indole (XI) was synthesized from
4-(4-chlorophenyl)-1,3-thiazol-2-amine and 2-phenyl-
1H-indole. Yield 0.65 g (78%), claret red crystals,
mp 147°C. IR spectrum, ν, cm–1: 3218 (NH), 3070
(C–Harom), 1458 (C=C). 1H NMR spectrum (DMSO-d6),
δ, ppm: 8.45 d (1H), 8.15 d (1H), 8.10 m (2H), 7.50–
7.60 m (8H), 7.40 m (2H). Mass spectrum, m/z
(Irel, %): 415 (100) [M + 1]+, 220 (34.3), 192 (12.4).
2-Methyl-3-[5-(4-nitrophenylsulfonyl)-1,3-thia-
zol-2-yldiazenyl]-1H-indole (XVI) was synthesized
from 5-(4-nitrophenylsulfonyl)-1,3-thiazol-2-amine
and 2-methyl-1H-indole. Yield 0.70 g (82%), red
crystals, mp 236°C. IR spectrum, ν, cm–1: 3416 (NH);
3070 (C–Harom); 2973, 2870 (C–Haliph); 1535 (C=C);
1
1310, 1157 (SO2), 1093 (S=O). H NMR spectrum
(DMSO-d6–CDCl3), δ, ppm: 12.51 br.s (NH), 8.36 d
(2H), 8.28 m (1H), 8.23 s (1H), 8.17 d (2H), 7.31 m
(1H), 7.21 m (2H), 2.71 s (3H). Mass spectrum, m/z
(Irel, %): 428 (100) [M + 1]+, 306 (5.5), 220 (13.5), 192
(5.6), 158 (30.7).
3-[4-(4-Chlorophenyl)-1,3-thiazol-2-yldiazenyl]-
1-methyl-2-phenyl-1H-indole (XII) was synthesized
from 4-(4-chlorophenyl)-1,3-thiazol-2-amine and
1-methyl-2-phenyl-1H-indole. Yield 0.69 g (81%),
orange crystals, mp 200°C. IR spectrum, ν, cm–1: 3050
(C–Harom); 2940, 2877 (C–Haliph); 1471 (C=C). 1H NMR
spectrum (DMSO-d6), δ, ppm: 8.50 d (1H), 8.00–
8.10 m (3H), 7.80 d (3H), 7.65 d (3H), 7.40–7.60 m
(4H), 3.90 s (3H). Mass spectrum, m/z (Irel, %): 429
(100) [M + 1]+, 234 (68.7), 206 (43.3).
3-[5-(4-Nitrophenylsulfonyl)-1,3-thiazol-2-yldi-
azenyl]-2-phenyl-1H-indole (XVII) was synthesized
from 5-(4-nitrophenylsulfonyl)-1,3-thiazol-2-amine
and 2-phenyl-1H-indole. Yield 0.76 g (78%), red
crystals, mp 290°C. IR spectrum, ν, cm–1: 3326 (NH);
3070 (C–Harom); 1541 (C=C); 1329, 1143 (SO2); 1047
(S=O). 1H NMR spectrum (DMSO-d6–CDCl3), δ, ppm:
12.54 br.s (NH), 8.47 m (1H), 8.31 m (3H), 8.16 d
(2H), 8.01 m (2H), 7.52–7.42 m (4H), 7.28 m (2H).
Mass spectrum, m/z (Irel, %): 490 (100) [M + 1]+, 220
(19.2), 192 (6.8), 158 (2.8).
3-[4-(4-Bromophenyl)-1,3-thiazol-2-yldiazenyl]-
2-methyl-1H-indole (XIII) was synthesized from
4-(4-bromophenyl)-1,3-thiazol-2-amine and 2-methyl-
1H-indole. Yield 0.62 g (78%), orange crystals,
mp 254°C. IR spectrum, ν, cm–1: 3288 (NH); 3070
(C–Harom); 2935, 2870 (C–Haliph); 1458 (C=C). 1H NMR
spectrum (DMSO-d6), δ, ppm: 12.60 br.s (NH), 8.30 m
(1H), 8.10 s (1H), 8.00 d (2H), 7.60 d (2H), 7.40 m
(1H), 7.30 m (2H), 2.80 s (3H). Mass spectrum, m/z
(Irel, %): 397 (100) [M]+, 240 (6.7), 158 (45.1).
1-Methyl-3-[5-(4-nitrophenylsulfonyl)-1,3-thia-
zol-2-yldiazenyl]-2-phenyl-1H-indole (XVIII) was
synthesized from 5-(4-nitrophenylsulfonyl)-1,3-thia-
zol-2-amine and 1-methyl-2-phenyl-1H-indole. Yield
0.79 g (79%), orange crystals, mp 184°C. IR spectrum,
ν, cm–1: 3063 (C–Harom); 2940, 2870 (C–Haliph); 1535
(C=C); 1317, 1157 (SO2); 1092 (S=O). 1H NMR spec-
trum (DMSO-d6–CDCl3), δ, ppm: 8.58 m (1H), 8.29 d
3-[4-(4-Bromophenyl)-1,3-thiazol-2-yldiazenyl]-
2-phenyl-1H-indole (XIV) was synthesized from
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 44 No. 4 2008

SAYLAM et al.
594
18. Metzger, J.V., Comprehensive Heterocyclic Chemistry,
Katritzky, A.R. and Rees, C.W., Eds., Oxford:
Pergamon, 1984, vol. 6.
19. Kornis, G., Comprehensive Heterocyclic Chemistry,
Katritzky, A.R. and Rees, C.W., Eds., Oxford:
Pergamon, 1984, vol. 6, part 4B, p. 545.
(2H), 8.09 d (2H), 7.61–7.51 m (5H), 7.38–7,31 m
(2H), 3.79 s (3H). Mass spectrum, m/z (Irel, %): 504
(10.8) [M + 1]+, 234 (2.3), 208 (100), 193 (4.6).
The authors are grateful to the Research Foundation
of Gazi University for support of this study.
20. Comba, P., Coord. Chem. Rev., 1993, vol. 123, p. 1.
21. Brown, J.L. and Lee, K.J., Coord. Chem. Rev., 1993,
REFERENCES
vol. 128, p. 89.
1. Zollinger, H., Color Chemistry: Syntheses, Properties,
and Applications of Organic Dyes and Pigments, 2003,
Zürich: Helvetica Chimica Acta, 3rd ed.
22. Albar, H.A., Shawali, A.S., and Abdaliah, M.A., Can. J.
Chem., 1993, vol. 71, p. 2144.
23. Binks, J.H. and Ridd, J.H., J. Chem. Soc., 1957, p. 2398.
2. Hallas, G., J. Soc. Dyers Colour., 1979, vol. 95, p. 285.
24. Jackson, A.H., Prasitpan, N., Shannon, P.V.R., and Tin-
3. Hallas, G. and Choi, J.H., Dyes Pigm., 1999, vol. 42,
ker, A.C., J. Chem. Soc., Perkin Trans. 1, 1987, p. 2543.
no. 3, p. 249.
25. Jackson, A.H. and Lynch, P.P., J. Chem. Soc., Perkin
Trans. 2, 1987, no. 10, p. 1483.
26. Suvorov, N.N., Avramenko, V.G., Dmitrevskaya, L.I.,
Smushkevich, Y.I., and Lyto, O.V., Zh. Obshch. Khim.,
1978, vol. 48, no. 4, p. 936.
4. Dickey, J.B., Towne, E.B., Bloom, M.S., Moore, W.H.,
Hill, H.M., Heynemann, H., Hedberg, D.G.,
Sievers, D.C., and Otis, M.V., J. Org. Chem., 1959,
vol. 24, p. 187.
5. Hallas, G. and Choi, J.H., Dyes Pigm., 1999, vol. 40,
27. Kurilo, G.N., Rostova, N.I., and Grinev, A.N., Zh. Org.
Khim., 1978, vol. 14, no. 12, p. 2627.
p. 119.
6. Metwally, M.A., Abdel-Latif, E., Amer, F.A., and
Kaupp, G., Dyes Pigm., 2004, vol. 60, p. 249.
7. Yen, M.S. and Wang, I.J., Dyes Pigm., 2004,
28. Inoue, S., Honda, H., and Abe, K., JPN Patent Appl.
no. 52-008334, 1977.
29. Bermes, R. and Keilhauer, H., FRG Patent Appl.
no. 2825296, 1979.
vol. 63, p. 1.
8. Schwander, H.R., Dyes Pigm., 1982, vol. 3, p. 133.
30. Yamada, S. and Tsunemitsu, K., JPN Patent 47-045172,
1972.
9. Weaver, M.A. and Shuttleworth, L., Dyes Pigm., 1982,
vol. 3, p. 81.
31. Inoue, S., Honda, H., Magara, Y., and Abe, K., JPN
Patent Appl. nos. 50-013682, 1975; 57-002831, 1982.
10. Karcı, F. and Ertan, N., Dyes Pigm., 2005, vol. 64,
no. 3, p. 243.
32. Kawai, H., Tsunemitsu, K., and Fujii, Y., JPN Patent
Appl. nos. 50-019827, 1975; 58-028295, 1983.
11. Ertan, N. and Eyduran, F., Dyes Pigm., 1995, vol. 27,
p. 313.
33. Dorsch, H.L. and Raue, R., US Patent no. 4104268,
1978.
34. Dorsch, H.L. and Raue, R., CH Patentschrift
no. 508441, 1975.
12. Ertan, N., Dyes Pigm., 2000, vol. 44, p. 41.
13. Wang, X., Yang, K., Kumar, J., Tripathy, S.K., Chitti-
babu, K.G., Li, L., and Lindsay, G., Macromolecules,
1998, vol. 31, p. 4126.
35. Dorsch, H.L. and Raue, R., CH Patentschrift
no. 562853, 1975.
14. Zabriskie, T.M., Mayne, C.L., and Ireland, C.M., J. Am.
Chem. Soc., 1998, vol. 110, p. 7919.
36. Dorsch, H.L. and Raue, R., DT Patent no. 1405313,
15. Hara, M., Asaro, K., Kawamoto, I.. Takiguchi, I., Kat-
sumata, S., Takahashi, K., and Nakano, H., J. Antibiot.,
1998, vol. 42, p. 1768.
16. Crews, P., Kakou, Y., and Quinoa, E., J. Am. Chem.
Soc., 1988, vol. 110, p. 4365.
17. Metzger, J.V., Thiazole and Its Derivatives, New York:
Wiley, 1979 (Chemistry of Heterocyclic Compounds
Series, vol. 34).
1975.
37. Rhyner, P. and Illy, H., CH Patentschrift no. 341248,
1959.
38. Dorsch, H.L. and Raue, R., FRG Patent Appl.
no. 2228147, 1973.
39. Seferoglu, Z. and Ertan, N., Russ. J. Org. Chem., 2007,
vol. 43, p. 1035.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 44 No. 4 2008