A one-pot synthesis of functionalized 2,3-dihydrothiazoles from isothiocyanates, primary alkylamines, and phenacyl bromides

Article abstract of DOI:10.1080/10426507.2010.487055

A simple, one-pot synthesis of N-(4-aryl-3-alkylthiazol-2(3H)-ylidene) anilines and N-(4-aryl-3-alkylthiazol-2(3H)-ylidene)benzamides via the reaction of primary alkylamines, -bromoketones, and phenylisothiocyanate or benzoylisothiocyanate is described. C

Full text of DOI:10.1080/10426507.2010.487055

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Phosphorus, Sulfur, and Silicon and the
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A One-Pot Synthesis of Functionalized
2,3-Dihydrothiazoles from
Isothiocyanates, Primary Alkylamines,
and Phenacyl Bromides
Issa Yavari a , Maryam Ghazvini a , Ashraf S. Shahvelayati a
Mohammad M. Ghanbari a
&
a Chemistry Department, Science and Research Campus , Islamic
Azad University , Ponak, Tehran, Iran
Published online: 13 Jan 2011.
To cite this article: Issa Yavari , Maryam Ghazvini , Ashraf S. Shahvelayati & Mohammad M. Ghanbari
(2010) A One-Pot Synthesis of Functionalized 2,3-Dihydrothiazoles from Isothiocyanates, Primary
Alkylamines, and Phenacyl Bromides, Phosphorus, Sulfur, and Silicon and the Related Elements, 186:1,
134-139, DOI: 10.1080/10426507.2010.487055
To link to this article: http://dx.doi.org/10.1080/10426507.2010.487055
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Phosphorus, Sulfur, and Silicon, 186:134–139, 2011
Copyright ꢀC Taylor & Francis Group, LLC
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426507.2010.487055
A ONE-POT SYNTHESIS OF FUNCTIONALIZED
2,3-DIHYDROTHIAZOLES FROM ISOTHIOCYANATES,
PRIMARY ALKYLAMINES, AND PHENACYL BROMIDES
Issa Yavari, Maryam Ghazvini, Ashraf S. Shahvelayati,
and Mohammad M. Ghanbari
Chemistry Department, Science and Research Campus, Islamic Azad University,
Ponak, Tehran, Iran
GRAPHICAL ABSTRACT
R'
N
O
MeCN
R
N
S
Br
R-NH2
+
+
R'-N=C=S
Ar
r.t., 12 h
Ar
12 Examples;Yield: 55-90%
Abstract A simple, one-pot synthesis of N-(4-aryl-3-alkylthiazol-2(3H)-ylidene)anilines and
N-(4-aryl-3-alkylthiazol-2(3H)-ylidene)benzamides via the reaction of primary alkylamines,
α-bromoketones, and phenylisothiocyanate or benzoylisothiocyanate is described.
Keywords Benzoylisotiosyanate; α-bromoketones; 2,3-dihydrothiazole; S-nucleophile;
phenylisothiocyanate; primary alkylamine
INTRODUCTION
Thiazoles occupy a prominent position among heterocycles. In nature, the thiazolium
ring is the chemically active center in the coenzyme derived from vitamin B1 (thiamin).
A large number of thiazoles obtained from microbial and marine origins exhibit important
biological effects such as antitumor, antifungal, antibiotic, and antiviral activities.1 Synthetic
thiazoles have also been shown to exhibit a wide variety of biological activities,2 while others
have found application as liquid crystals3 and cosmetic sunscreens.4 The classical method
for the synthesis of thiazoles is the Hantzsch process, in which a α-haloketone is condensed
with a thioamide.5 This method gives excellent yields for simple thiazoles; however, for
some substituted examples, low yields have been reported.6,7
Received 12 January 2010; accepted 16 April 2010.
Address correspondence to Issa Yavari, Chemistry Department, Islamic Azad University, Science and
Research Branch, Ponak, PO Box 14515/775, Tehran 1477893855, Iran. E-mail: yavarisa@modares.ac.ir
134

FUNCTIONALIZED 2,3-DIHYDROTHIAZOLES
135
As part of our current studies on the development of new routes in thiazole synthe-
sis,8–11 we report an efficient procedure for direct synthesis of N-(4-aryl-3-alkylthiazol-
2(3H)-ylidene)anilines 4a–4h and N-(4-aryl-3-alkylthiazol-2(3H)-ylidene)benzamides
4i–4l from primary alkylamines 1, isothiocyanates 2, and α-bromoketones 3, at r.t.
(Scheme 1). This catalyst-free and one-pot synthetic method is facile; the work-up
procedure is easy and gives pure target compounds.
R'
N
O
MeCN
R
N
S
Br
R-NH2
R
+
+
R'-N=C=S
Ar
r.t., 12 h
Ar
Yiled (%)
3
4
Ar
1
2
Ar
R'
____R_'__
_____________
R
n-Bu
n-Bu
_________
a
b
a
b
4-MeO-C6H4
4-Br-C6H4
Ph
Bz
a
b
c
d
n-Bu
a
b
c
d
e
f
4-MeO-C6H4
4-Br-C6H4
82
90
75
88
85
84
80
82
65
68
66
55
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Bz
Bz
Bz
Bz
c-Hexyl
Bn
p-tolylCH2
p-tolylCH2
Bn
4-MeO-C6H4
4-Br-C6H4
p-tolylCH2
4-MeO-C6H4
4-Br-C6H4
Bn
g
h
i
c-Hexyl
c-Hexyl
n-Bu
4-MeO-C6H4
4-Br-C6H4
4-MeO-C6H4
4-Br-C6H4
j
n-Bu
k
l
Bn
4-MeO-C6H4
4-Br-C6H4
Bn
Scheme 1 Synthesis of compounds 4.
RESULTS AND DISCUSSION
The reaction of 1, 2, and 3 proceeds smoothly in MeCN at r.t. to produce N-
(4-aryl-3-alkylthiazol-2(3H)-ylidene)anilines (4a–4h) and N-(4-aryl-3-alkylthiazol-2(3H)-
ylidene)benzamides (4i–4l) in moderate to good yields (Scheme 1). The structures of com-
pounds 4a–4l were deduced from their IR, 1H NMR, and 13C NMR spectral data. The mass
spectra of these compounds displayed molecular ion peaks at appropriate m/z values. The
1H NMR spectrum of 4a in CDCl3 showed two singlets for the methoxy (δ = 3.88) and
methine (δ = 5.70) protons, together with characteristic signals for the n-butyl and aryl
protons. The 13C NMR spectrum of 4a showed 16 signals in agreement with the proposed
structure. The 1H and 13C NMR spectra of 4b–4l are similar to those for 4a except for the
alkyl and aryl substituents, which exhibit characteristic signals in the appropriate regions
of the NMR spectra.
Although the mechanistic details of the reaction are not known, a plausible rational-
ization can be advanced to explain the product formation (Scheme 2). Presumably, the initial
event is the formation of unsymmetrical thiourea 5 from the amine and heterocumulene
2. Thiourea 5 is alkylated by bromoketone 3 to furnish intermediate 6, which undergoes
cyclization to generate 7. Dehydration of intermediate 7 affords product 4.
In conclusion, we revealed a three-component synthesis of N-(4-aryl-3-alkylthiazol-
2(3H)-ylidene)anilines and N-(4-aryl-3-alkylthiazol-2(3H)-ylidene)benzamides from pri-
mary alkylamines, α-bromoketones, and isothiocyanate. The advantage of the present

136
I. YAVARI ET AL.
O
Br
S
Ar
3
R-NH2
+
R'-N=C=S
RHN
NHR'
_
HBr
1
2
5
R'
R'
R'
N
N
N
R
_
N
R
N
S
R
H2O
S
N
S
H
O
OH
Ar
Ar
Ar
6
7
4
Scheme 2 Proposed mechanism for the formation of compounds 4.
procedure is that the reaction is performed under neutral conditions by simple mixing of
the starting materials. This catalyst-free procedure provides an acceptable one-pot method
for the preparation of functionalized 2,3-dihydrothiazoles.
EXPERIMENTAL
Compounds 1, 2, and 3 were obtained from Merck and were used without further
purification; IR spectra: Shimadzu IR-460 spectrometer; 1H and 13C NMR spectra: Bruker
DRX-300 Avance instrument; in CDCl3 at 300 MHz and 75 MHz, respectively, δ in ppm J
in Hz; EI-MS (70 eV): Finningan-MAT-8430 mass spectrometer, in m/z. Elemental analyses
(C, H, and N) were performed with a Heraeus CHN-O-Rapid analyzer.
Typical Procedure for the Preparation of Compounds 4
To a stirred solution of alkylamine (1, 2 mmol) and isothiocyanate (2, 2 mmol) in
10 mL of MeCN, α-bromoketone (3, 2 mmol) was added at r.t. After completion of the
reaction (1–2 h), as indicated by TLC (AcOEt:hexane, 2:1), the solvent was removed under
reduced pressure, and the residue was purified by silica gel (SiO2; Merck 230–240 mesh)
column chromatography (CC) using a 5:1, hexane:AcOEt mixture as eluent to afford 4.
N-(3-Butyl-4-(4-methoxyphenyl)thiazol-2(3H)-ylidene)aniline (4a). Pale
yellow oil, yield: 0.55 g (82%). IR (KBr): 1619, 1569, 1480, 1178 cm−1 1H NMR (300
.
3
MHz, CDCl3): 0.81 (3 H, t, J 7.2, Me), 1.20–1.26 (2 H, m, CH2), 1.62–1.68 (2 H, m,
3
CH2), 3.78 (2 H, t, J 7.1, CH2), 3.88 (3 H, s, MeO), 5.70 (1 H, s, CH), 6.97 (2 H, d,
3J 8.1, C6H4), 7.35 (2 H, d, 3J 8.1, C6H4), 7.04–7.38 (5 H, m, Ph). 13C NMR (75 MHz,
CDCl3): 14.1 (Me), 20.1 (CH2), 30.5 (CH2), 45.5 (CH2), 55.7 (MeO), 98.1 (CH), 114.4 (2
CH), 122.0 (2 CH),129.8 (2 CH), 130.6 (2 CH), 123.3 (CH), 126.2 (C), 138.5 (C), 148.9
(C), 158.1 (C), 160.5 (C N). Anal. Calcd for C20H22N2OS (338.47): C, 70.97; H, 6.55;

FUNCTIONALIZED 2,3-DIHYDROTHIAZOLES
137
N, 8.28%. Found: C, 70.30; H, 6.71; N, 8.41%. EI-MS: m/z (%): 338 (M+, 100), 282 (13),
206 (39), 133 (55), 77 (14).
N-(4-(4-Bromophenyl)-3-butylthiazol-2(3H)-ylidene)aniline (4b). Color-
less powder; mp 239–242◦C; 0.69 g (90%). IR (KBr): 1613, 1563, 1479 cm−1. 1H NMR
(300 MHz, CDCl3): 0.75 (3 H, t, 3J 7.1, Me), 1.26–1.31 (2 H, m, CH2), 1.66–1.71 (2 H,
m, CH2), 4.63 (2 H, t, 3J 7.2, CH2), 6.69 (1 H, s, CH), 7.27 (2 H, d, 3J 8.0, C6H4), 7.66 (2
H, d, 3J 8.0, C6H4), 7.34–7.64 (5 H, m, Ph). 13C NMR (75 MHz, CDCl3): 13.9 (Me), 19.6
(CH2), 30.2 (CH2), 49.5 (CH2), 105.8 (CH), 124.7 (2 CH), 125.9 (C), 127.4 (C), 128.9
(CH), 130.5 (2 CH), 131.4 (2 CH), 133.0 (2 CH), 138.1 (C), 142.3 (C), 169.1 (C N).
Anal. Calcd for C19H19BrN2S (387.34): C, 58.92; H, 4.94; N, 7.23%. Found: C, 59.22;
H, 4.76; N, 7.39%. EI-MS: m/z (%): 388 (M+ + 2, 100), 386 (M+, 100), 332 (12.5), 330
(12.5), 256 (41), 254 (41), 133 (58), 77 (17).
N-(4-(4-Methoxyphenyl)-3-(4-methylbenzyl)thiazol-2(3H)-ylidene)aniline
1
(4c). Pale yellow oil; 0.58 g (75%). IR (KBr): 1634, 1576, 1471, 1119 cm−1. H NMR
(300 MHz, CDCl3): 2.23 (3 H, s, Me), 3.85 (3 H, s, MeO), 5.10 (2 H, s, CH2), 5.78 (1
3
3
H, s, CH), 6.89 (2 H, d, J 8.0, C6H4), 7.17 (2 H, d, 3J 8.0, C6H4), 6.98 (2 H, d, J 8.1,
C6H4), 7.04 (2 H, d, 3J 7.8, Ph), 7.05–7.16 (3 H, m, Ph), 7.35 (2 H, t, 3J 7.8, C6H4). 13
C
NMR (75 MHz, CDCl3): 21.5 (Me), 50.1 (CH2), 55.8 (MeO), 98.3 (CH), 114.6 (2 CH),
124.3 (2 CH), 127.6 (2 CH), 129.5 (2 CH), 129.6 (CH), 130.0 (2 CH), 131.0 (2 CH), 126.2
(C), 129.9 (C), 137.2 (C), 144.7 (C), 149.8 (C), 156.9 (C), 165.7 (C N). Anal. Calcd for
C24H22N2OS (386.51): C, 74.58; H, 5.74; N, 7.25%. Found: C, 74.72; H, 5.91; N, 7.40%.
EI-MS: m/z (%): 386 (M+, 15), 282 (18), 181 (81), 105 (100), 77 (22).
N-(4-(4-Bromophenyl)-3-(4-methylbenzyl)thiazol-2(3H)-ylidene)aniline
(4d). Colorless powder; mp 163–167◦C; 0.77 g (88%). IR (KBr): 1677, 1542, 1466 cm−1
.
1H NMR (300 MHz, CDCl3): 2.30 (3 H, s, Me), 6.04 (2 H, s, CH2), 6.63 (1 H, s, CH),
7.02 (2 H, d, 3J 8.0, C6H4), 7.09 (2 H, d, 3J 8.0, C6H4), 7.25 (2 H, d, 3J 7.9, C6H4), 7.64
(2 H, d, 3J 7.8, Ph), 7.36 (1 H, t, 3J 7.8, Ph), 7.43 (2 H, t, 3J 7.8, Ph), 7.57 (2 H, d, 3J 7.8,
C6H4). 13C NMR (75 MHz, CDCl3): 21.5 (Me), 52.9 (CH2), 105.0 (CH), 124.4 (2 CH),
127.5 (2 CH), 128.9 (CH), 130.1 (2 CH), 130.6 (2 CH), 131.3 (2 CH), 133.1 (2 CH), 125.9
(C), 130.3 (C), 138.9 (C), 136.2 (C), 138.2 (C), 143.3 (C), 170.0 (C N). Anal. Calcd for
C23H19BrN2S (435.38): C, 63.45; H, 4.40; N, 6.43%. Found: C, 63.12; H, 4.58; N, 6.59%.
EI-MS: m/z (%): 436 (M+ + 2, 13), 434 (M+, 12.5), 344 (11), 342 (11), 250 (14.4), 181
(73), 105 (100), 77 (19).
N-(3-Benzyl-4-(4-methoxyphenyl)thiazol-2(3H)-ylidene)aniline (4e). Pale
yellow powder; mp 110–119◦C; 0.63 g (85%). IR (KBr): 1603, 1573, 1499, 1172 cm−1
.
1H NMR (300 MHz, CDCl3): 3.84 (3 H, s, MeO), 5.14 (2 H, s, CH2), 6.04 (1 H, s, CH),
3
6.94 (2 H, d, J 8.0, C6H4), 7.28 (2 H, d, 3J 8.0, C6H4), 6.97–7.34 (10 H, m, 2 Ph). 13C
NMR (75 MHz, CDCl3): 49.0 (CH2), 55.7 (MeO), 96.0 (CH), 114.3 (2 CH), 122.0 (2 CH),
133.5 (CH), 124.1 (C), 127.5 (2 CH), 128.7 (2 CH), 129.1 (C), 129.8 (2 CH), 130.8 (2 CH),
137.8 (CH), 140.7 (C), 147.1 (C), 154.3 (C), 160.6 (C N). Anal. Calcd for C23H20N2OS
(372.48): C, 74.16; H, 5.41; N, 7.52%. Found: C, 74.83; H, 5.64; N, 7.76%. EI-MS: m/z
(%): 372 (M+, 33), 268 (35), 181 (76), 105 (100), 77 (22).
N-(3-Benzyl-4-(4-bromophenyl)thiazol-2(3H)-ylidene)aniline (4f). Cream
1
powder; mp 132–135◦C; 0.71 g (84%). IR (KBr): 1616, 1579, 1483 cm−1. H NMR
(300 MHz, CDCl3): 5.16 (2 H, s, CH2), 5.87 (1 H, s, CH), 7.09–7.28 (5 H, m, Ph), 7.36
3
(3 H, t, 3J 7.7, Ph), 7.49 (2 H, d, 3J 7.9, C6H4), 7.66 (2 H, d, J 7.7, Ph), 7.87 (2 H, d, 3J
7.9, C6H4). 13C NMR (75 MHz, CDCl3): 50.2 (CH2), 104.1 (C), 127.4 (CH), 128.9 (2
CH), 129.2 (CH), 129.9 (2 CH), 130.0 (C), 130.8 (2 CH), 130.9 (2 CH), 131.0 (CH), 132.2

138
I. YAVARI ET AL.
(2 CH), 132.3 (C), 132.6 (2 CH), 132.7 (C), 151.5 (C), 157.1 (C N). Anal. Calcd for
C22H17BrN2S (421.35): C, 62.71; H, 4.07; N, 6.65%. Found: C, 63.04; H, 4.21; N, 6.79%.
EI-MS: m/z (%): 422 (M+ + 2, 31), 420 (M+, 30.6), 330 (19), 328 (19), 237 (38), 181 (73),
105 (100), 77 (17).
N-(3-Cyclohexyl-4-(4-methoxyphenyl)thiazol-2(3H)-ylidene)aniline (4g).
1
Pale yellow oil; 0.58 g (80%). IR (KBr): 1644, 1528, 1465, 1180 cm−1. H NMR (300
MHz, CDCl3): 1.13–2.71 (10 H, m, 5 CH2), 3.80–3.82 (H, m, CH), 3.88 (3 H, s, MeO),
3
5.61 (1 H, s, CH), 6.97 (2 H, d, J 7.6, C6H4), 7.28 (2 H, d, 3J 7.6, C6H4), 7.06–7.38 (5
H, m, Ph). 13C NMR (75 MHz, CDCl3): 25.4 (CH2), 26.6 (2 CH2), 29.2 (2 CH2), 47.6
(CH), 55.7 (MeO), 98.3 (CH), 114.3 (2 CH), 122.0 (2 CH), 122.1 (C), 123.5 (C), 125.5
(CH), 129.9 (2 CH), 130.7 (2 CH), 130.8 (C), 141.4 (C), 160.4 (C N). Anal. Calcd for
C22H24N2OS (364.50): C, 72.49; H, 6.64; N, 7.69%. Found: C, 72.78; H, 6.71; N, 7.81%.
EI-MS: m/z (%): 364 (M+, 100), 282 (15), 206 (38), 159 (55), 77 (31).
N-(4-(4-Bromophenyl)-3-cyclohexylthiazol-2(3H)-ylidene)aniline (4h).
1
Pale yellow oil; 0.68 g (82%). IR (KBr): 1620, 1588, 1470 cm−1. H NMR (300 MHz,
CDCl3): 1.15–2.71 (10 H, m, 5 CH2), 3.78–3.80 (H, m, CH), 5.69 (H, s, CH), 7.07–7.48
(5 H, m, Ph), 7.27 (2 H, d, 3J 8.0, C6H4), 7.76 (2 H, d, 3J 8.0, C6H4). 13C NMR (75 MHz,
CDCl3): 25.7 (CH2), 26.8 (2 CH2), 30.7 (2 CH2), 46.0 (CH), 105.8 (CH), 129.7 (CH), 130.4
(2 CH), 130.8 (2 CH), 131.0 (C), 131.5 (C), 132.2 (2 CH), 132.6 (2 CH), 133.0 (C), 143
(C), 165.8 (C N). Anal. Calcd for C21H21BrN2S (413.37): C, 61.02; H, 5.12; N, 6.78%.
Found: C, 61.48; H, 5.30; N, 6.90%. EI-MS: m/z (%): 414 (M++2, 100), 412 (M+, 100),
332 (16.5), 330 (16), 256 (29), 254 (29.5), 159 (48), 77 (26).
N-(3-Butyl-4-(4-methoxyphenyl)thiazol-2(3H)-ylidene)benzamide (4i).
Cream powder; mp 118–121◦C; 0.47 g (65%). IR (KBr): 1591, 1473, 1311 cm−1. 1H NMR
3
(300 MHz, CDCl3): 0.86 (3 H, t, J 7.3, Me), 1.27–1.29 (2 H, m, CH2), 1.72–1.74 (2 H,
m, CH2), 4.24 (2 H, t, 3J 7.2, CH2), 3.90 (3 H, s, MeO), 6.50 (1 H, s, CH), 7.03 (2 H, d,
3J 7.8, C6H4), 7.33 (2 H, d, 3J 7.8 Hz, C6H4), 7.45–7.48 (3 H, m, Ph). 8.37 (2 H, d, 3J 8.0,
Ph). 13C NMR (75 MHz, CDCl3): 14.0 (Me), 20.2 (CH2), 30.9 (CH2), 47.4 (CH2), 55.8
(MeO), 107.3 (CH), 114.6 (2 CH), 123.4 (C), 128.4 (2 CH), 129.6 (2 CH), 131.2 (2 CH),
131.7 (CH), 137.5 (C), 139.5 (C), 147.0 (C), 160.9 (C N), 174.3 (C O). Anal. Calcd for
C21H22N2O2S (366.48): C, 68.82; H, 6.05; N, 7.64%. Found: C, 69.08; H, 6.21; N, 7.81%.
EI-MS: m/z (%): 366 (M+, 28), 310 (31), 105 (100), 77 (50).
N -(4-(4-Bromophenyl)-3-butylthiazol-2(3H )-ylidene)benzamide (4j).
Cream powder; mp 138–158◦C; 0.56 g (68%). IR (KBr): 1599, 1487, 1352 cm−1. 1H NMR
(300 MHz, CDCl3): 0.87 (3 H, t, 3J 7.3, Me), 1.27–1.29 (2 H, m, CH2), 1.71–1.73 (2 H,
m, CH2), 4.22 (2 H, 3J 7.2, CH2), 6.55 (1 H, s, CH), 7.29 (2 H, d, 3J 8.0, C6H4), 7.67 (2
H, d, 3J 8.0, C6H4), 7.44–7.52 (3 H, m, Ph), 8.35 (2 H, d, 3J 8.0, Ph). 13C NMR (75 MHz,
CDCl3): 14.0 (Me), 20.2 (CH2), 30.9 (CH2), 47.4 (CH2), 108.2 (CH), 124.5 (C), 128.4 (2
CH), 129.6 (2 CH), 130.2 (C), 131.4 (2 CH), 131.8 (CH), 132.5 (2 CH), 137.3 (C), 138.4
(C), 168.8 (C N), 174.5 (C O). Anal. Calcd for C20H19BrN2OS (415.35): C, 57.33; H,
4.61; N, 6.74%. Found: C, 58.11; H, 4.77; N, 6.92%. EI-MS: m/z (%): 416 (M++2, 29),
414 (M+, 29), 360 (33), 358 (32), 105 (100), 77 (48).
N-(3-Benzyl-4-(4-methoxyphenyl)thiazol-2(3H)-ylidene)benzamide (4k).
Colorless powder; mp 116–125◦C; 0.53 g (66%). IR (KBr): 1607, 1477, 1351, 1167 cm−1
.
1H NMR (300 MHz, CDCl3): 3.86 (3 H, s, MeO), 5.50 (2 H, s, CH2), 6.53 (1 H, s, CH),
6.90 (2 H, d, 3J 8.0, C6H4), 7.14 (2 H, d, 3J 8.0, C6H4), 7.04–7.28 (5 H, m, Ph), 7.42–7.48 (3
H, m, Ph), 8.30 (2 H, d, 3J 8.1, Ph). 13C NMR (75 MHz, CDCl3): 50.7 (CH2), 55.8 (MeO),
107.4 (CH), 114.4 (2 CH), 123.0 (C), 127.6 (2 CH), 128.0 (CH), 128.4 (2 CH), 128.9 (2

FUNCTIONALIZED 2,3-DIHYDROTHIAZOLES
139
CH), 129.7 (2 CH), 131.4 (2 CH), 131.8 (CH), 139.8 (C), 137.3 (C), 139.6 (C), 161.0 (C),
169.5 (C N), 174.6 (C O). Anal. Calcd for C24H20N2O2S (400.49): C, 71.98; H, 5.03;
N, 6.99%. Found: C, 72.12; H, 4.91; N, 7.21%. EI-MS: m/z (%): 400 (M+, 26), 309 (91),
105 (100), 77 (64).
N-(3-Benzyl-4-(4-bromophenyl)thiazol-2(3H)-ylidene)benzamide (4l).
Colorless powder; mp 140–148◦C; 0.49 g (55%). IR (KBr): 1558, 1480, 1351 cm−1
.
1H NMR (300 MHz, CDCl3): 5.50 (2 H, s, CH2), 6.58 (1 H, s, CH), 7.05 (2 H, d, 3J 7.8,
C6H4), 7.53 (2 H, d, 3J 7.8, C6H4), 7.04–7.27 (5 H, m, Ph), 7.42–7.49 (3 H, m, Ph), 8.31 (2
H, d, 3J 7.9, Ph). 13C NMR (75 MHz, CDCl3): 48.2 (CH2), 108.7 (CH), 123.9 (C), 127.5
(2 CH), 128.2 (CH), 128.4 (2 CH), 129.1 (2 CH), 129.7 (2 CH), 130.1 (C), 131.5 (2 CH),
131.9 (CH), 132.3 (2 CH), 136.8 (C), 142.2 (C), 152.3 (C), 170.0 (C N), 178.1 (C O).
Anal. Calcd for C23H17BrN2OS: (449.36): C, 61.48; H, 3.81; N, 6.23%. Found: C, 61.81;
H, 3.92; N, 6.38%. EI-MS: m/z (%): 450 (M++2, 23), 448 (M+, 23), 359 (91), 357 (91),
105 (100), 77 (58).
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