Microwave-assisted synthesis of N-(1H-imidazoline-2-YL)-1H-benzimidazol-2- amine and its N-functionalized derivatives

Article abstract of DOI:10.1080/00397911.2011.567883

(Chemical Equation Presented) N-(1H-Imidazoline-2-yl)-1H-benzimidazol-2- amine hydroiodide was synthesized with excellent yields, and it was converted to free base by using triethylamine under microwave irradiation (MWI) conditions. Its new Mannich, benzy

Full text of DOI:10.1080/00397911.2011.567883

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Microwave-Assisted Synthesis of N-(1H-
Imidazoline-2-yl)-1H-benzimidazol-2-
amine and Its N-Functionalized
Derivatives
Süleyman Servi a & Murat Genc b
a Department of Chemistry, Faculty of Science, University of Firat,
Elazig, Turkey
b Department of Chemistry, Faculty of Science and Art, University of
Adiyaman, Adiyaman, Turkey
Accepted author version posted online: 02 Nov 2011.Version of
record first published: 29 May 2012.
To cite this article: Süleyman Servi & Murat Genc (2012): Microwave-Assisted Synthesis of N-
(1H-Imidazoline-2-yl)-1H-benzimidazol-2-amine and Its N-Functionalized Derivatives, Synthetic
Communications: An International Journal for Rapid Communication of Synthetic Organic Chemistry,
42:19, 2797-2805
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Synthetic Communications1, 42: 2797–2805, 2012
Copyright # Taylor & Francis Group, LLC
ISSN: 0039-7911 print=1532-2432 online
DOI: 10.1080/00397911.2011.567883
MICROWAVE-ASSISTED SYNTHESIS OF N-(1H-
IMIDAZOLINE-2-YL)-1H-BENZIMIDAZOL-2-AMINE
AND ITS N-FUNCTIONALIZED DERIVATIVES
Su¨leyman Servi1 and Murat Genc2
1Department of Chemistry, Faculty of Science, University of Firat,
Elazig, Turkey
2Department of Chemistry, Faculty of Science and Art, University of
Adiyaman, Adiyaman, Turkey
GRAPHICAL ABSTRACT
Abstract N-(1H-Imidazoline-2-yl)-1H-benzimidazol-2-amine hydroiodide was synthesized
with excellent yields, and it was converted to free base by using triethylamine under micro-
wave irradiation (MWI) conditions. Its new Mannich, benzyl, and allyl derivatives were
synthesized.
Keywords 2-Aminobenzimidazole; guanidine; Mannich base; microwave irradiation
INTRODUCTION
The benzimidazole ring system is an important nucleus for drug discovery and
represents the core structure of a number of biologically significant molecules.[1–3]
2-Aminobenzimidazoles and 2-aminoimidazolines exhibit diverse pharmacological
features.[4–6] These compounds are compounds bearing guanidine functional groups.
This functional group is found in numerous biologically active natural products and
several drugs.[7,8] In addition to their biological roles, guanidine derivatives are widely
utilized in synthetic organic chemistry as strong bases. Because of their strongly basic
character, guanidines can be considered superbases, and chiral guanidines are of
potential use as asymmetric reagents.[9]
Received February 12, 2011.
Address correspondence to Suleyman Servi, Department of Chemistry, Faculty of Science, Firat
¨
University, Elazig 23119, Turkey. E-mail: sservi@firat.edu.tr
2797

2798
S. SERVI AND M. GENC
There are diverse synthetic routes to cyclic 2-aminobenzimidazoles; however, the
search for a high-yielding synthesis of these useful molecules is still ongoing.[10–12]
Direct synthetic approaches for the preparation of guanidine-derived products in
good yields under mild conditions are of great interest in medicinal chemistry. The
biological and pharmacological activities of imidazolines and the benzimidazoles
prompted the development of microwave-assisted synthetic strategies for preparation
of biheterocyclic dihydroimidazoles analogs.
We have previously reported the synthesis of some benzimidazole and imidazo-
line compounds.[13–16] This article reports the first microwave–assisted synthesis of N-
(1H-imidazoline-2-yl)-1H-benzimidazol-2-amine and its Mannich bases and benzyl
and allyl derivatives. These compounds have not been described in the literature until
now, except for compound 8.[17]
RESULTS AND DISCUSSION
Although 2-aminobenzimidazoles play an important role in biological and
pharmaceutical areas, efficient methods for the synthesis of these molecules are lim-
ited. The classical approaches to 2-aminobenzimidazoles employ o-phenylenedia-
mine as precursors. Existing methods for the solution-phase synthesis of
2-aminobenzimidazole derivatives typically involve cyclization of an o-phenylenedia-
mine using cyanogen bromide or its equivalent to provide the 2-aminobenzimidazole
ring system.[18] Other approaches include the aromatic nucleophilic substitution
(SNAr) reactions of 2-chlorobenzimidazoles, N-nucleophiles, and Pd-catalyzed coup-
ling of 2-halobenzimidazoles with amines.[19] These methods might suffer from the
limited availability of the starting materials, harsh conditions, poor yields, narrow
scope, and=or expensive catalysts. Therefore, more efficient and facile routes to these
useful molecules under mild conditions are needed.
The aim of this study is to synthesize N-(1H-imidazoline-2-yl)-1H-benzimida-
zol-2-amine using both microwave and conventional synthetic methods, using differ-
ent precursors than those previously reported.[13,14] In this work, the new derivatives
of this compound were synthesized. These compound contains both imidazoline and
benzimidazole rings. They are polyfunctional planar molecule with a delocalized p
electronic system. Compound 3 contains five nitrogen atoms, which may act as basic
centers, and it has five labile N–H bonds.[20]
2-Methylmercapto-4,5-dihydroimidazole hydroiodide (1) was used as the
starting reagent. Synthesis of N-(1H-imidazoline-2-yl)-1H-benzimidazol-2-amine
hydroiodide (2) was carried out from the reaction of 2-aminobenzimidazole with
compound 1. The reactions were tried using several solvents such as pyridine, meth-
anol, ethanol, and dimethylformamide (DMF) to synthesize compound 2. The reac-
tion was successfully carried out by refluxing with conventional heating in pyridine
for 12 h. The product was obtained as the hydroiodide salt of compound 3. The yield
of the reaction was 75% with this conventional method. Test reactions were carried
out to modify the conventional method for microwave-assisted reaction conditions.
These reactions were performed both atmosphere pressure (Figure 1) and 1 bar
pressure under microwave irradiation conditions in a sealed tube. The product
was isolated in good yields (90%) in both cases. Compound 2 was converted to

N-(1H-IMIDAZOLINE-2-YL)-1H-BENZIMIDAZOL-2-AMINE
2799
Figure 1. Profile of change in temperature under microwave irradiation by modulation of emitted power
for the reaction of 2-aminobenzimidazole with compound 1 (ramp time, 4 min; and hold time, 52 min;
power, 100 W). (Figure is provided in color online.)
the free base by refluxing with triethylamine for 10 min under microwave irradiation
conditions (Scheme 1).
In the light of the available literature and as a continuation of our previous stu-
dies on benzimidazole- and imidazoline-derived compounds, we aimed to synthesize
some new benzimidazole derivatives as potential biologic active compounds. Because
benzimidazole derivatives including piperidine and the piperazine core are widely
used in medicine and pharmacology, we aimed to design and synthesize some new
4-methylpiperidine and 2-methyl piperazine derivatives of compound 3.
Compound 3 has three appropriate NH functional groups on which to perform
nucleophilic substitution and aminomethylation (Mannich bases) reactions. These
reactions were carried out on NH functional groups with four different types of
reactivities in different reaction conditions. In spite of similar compounds have been
synthesized in the literature previously,[21,22] these derivatives were first synthesized
by treatment of compound 3 with 4-methylpiperidine, N-ethyl piperazine, or
2-methlypiperidine and formaldehyde. In Mannich reactions, different molar ratios
of formaldehyde and various saturated cyclic secondary amines were used to synthe-
size the compounds 4–6. In the case of excessive use of 4-methyl piperazine or 4-ethyl
piperazine, the compounds 4 or 5 were only isolated in these reactions. Synthesis of
Scheme 1. Synthetic pathway for the synthesis of compound 3.

2800
S. SERVI AND M. GENC
Scheme 2. Synthesis of Mannich bases, benzyl and allyl derivatives of 3.
compound 6 was performed with acid catalysis, and the product was isolated as the
HCl salt[23] The synthesis of this compound failed without acid catalysis. N-Benzyl
derivatives of 3 (compounds 7 and 8) have been synthesized by using 1,4-bis(bromo-
methyl)benzene and 1-chloro-2-(chloromethyl) benzene in dimethylsulfoxide
(DMSO) and basic medium. The structure of 8 was characterized by infrared (IR)
1
and H NMR spectroscopy and single-crystal x-ray diffraction.[17] The synthesis of
N-allyl derivative of 3 (compound 9) was carried out by the reaction of 3 with allyl
bromide. Compound 10 was obtained by reacting 3 with thiophene-2-carbonyl chlor-
ide in tetrahydrofuran (THF) and basic medium. (Scheme 2) IR and 1H NMR spectra
clearly indicated the formation of these products.
CONCLUSION
In summary, an efficient strategy for the synthesis of N-(1H-imidazoline-2-
yl)-1H-benzimidazol-2-amine was developed. The reaction time was reduced from
hours to minutes. The compound that might possess biological and pharmaceutical
activities was easily synthesized in good yields via a microwave-assisted method.
Mannich, benzyl, and allyl derivatives of this new guanidine compound were first
synthesized by aminomethylation and nucleophilic substitution reactions.
EXPERIMENTAL
All reagents were of commercial quality, and solvents were used without
further purification. IR spectra were determined on a Perkin-Elmer Spectrum One

N-(1H-IMIDAZOLINE-2-YL)-1H-BENZIMIDAZOL-2-AMINE
2801
Fourier transform–infrared (FT-IR) spectrometer. Thin-layer chromatography
(TLC) was carried out on aluminum sheets (105) precoated with silica gel 60 F254
(Merck). Column chromatography was carried out on silica gel 60 (40–63 mM).
Melting points (uncorrected) were determined with an Electrothermal IA 9100
apparatus. NMR spectra were recorded on Bruker 300-MHz and 400-MHz
spectrometers. Chemical shifts d are reported in parts per million (ppm) relative
to CHCl3 (1H NMR 7.27), CDCl3 (13C NMR 77.0), and dimethylsulfoxide (DMSO)
(1H NMR 2.51 and 3.36 for water present in DMSO), DMSO-d6(13C NMR 39.51),
and tetramethylsilane (TMS) as internal standard. The microwave-assisted reactions
were performed with a single-mode CEM Discover Labmate instrument (producing
continuous irradiation at 2450 MHz), which has an in situ magnetic stirrer,
irradiation monitored by PC computer, IR measurement, and continuous feedback
temperature control.
Compound 2
Conventional synthesis of compound 2. 2-Aminobenzimidazole
(22.5 mmol) and 2-methylmercapto-4,5-dihydroimidazole hydroiodide (22.5 mmol)
were dissolved in pyridine (30 mL), and the mixture was refluxed for 12 h. Caution:
The noxious gas CH3SH evolves during the synthesis, and it should be trapped with
a concentrated aqueous solution of NaOH and then destroyed with sodium hypo-
chlorite. After the reaction completed, pyridine was evaporated under vacuum.
The crude product was dissolved in ethanol (2 mL) and then diethyl ether (30 mL)
was added. The precipitate was filtered off and dried in vacuum. The products were
purified by crystallization from ethanol.
Microwave-irradiation synthesis of compound 2. 2-Aminobenzimidazole
(22.5 mmol) and 2-methylmercapto-4,5-dihydroimidazole hydroiodide (22.5 mmol)
was dissolved in pyridine (30 mL), and the mixture was irradiated in the microwave
oven at 100 W for 52 min at 125 ꢀC. The next process is as described in the conven-
tional synthesis method.
N-(1H-Imidazoline-2-yl)-1H-benzimidazol-2-amine hydroiodide (com-
pound 2). Yield 90%, white powder, mp 239–242 ꢀC (ethanol); IR (KBr) tmax
:
3465 (benzimidazole N-H stretching), 3383 (þ N-H stretching), 3176 (N-H
stretching), 2892 (aliphatic C-H stretching), 1634 (C¼Nþ stretching), 1591 (C¼C
stretching), 1535 (N-H bending). 1H NMR (DMSO-d6, 300 MHz) d: 3.65 (s, 4H, imi-
dazoline CH2), 7.19–7.37 (m, 4H, Ar-H), 8.38 (s, 2H, HI and endo NH), 12.43 (s, 2H,
benzimidazole NH and exo NH). 13C NMR (DMSO-d6, 75 MHz), d: 44.54, 111.83,
123.34, 130.72, 152.50, and 160.93, Anal. calcd. for C10H12N5I (329,14): C, 36.49;
H, 3.67; N, 21.28. Found: C, 36.56; H, 3.89; N, 21.85.
Compound 3
Synthesis of compound 3. A solution of 2 (22.5 mmol) in 100 mL (THF) and
9.3 mL triethylamine (67.6 mmol) was added. The mixture was refluxed for 10 min
under microwave irradiation conditions (ramp time, 2 min; hold time, 10 min; power,
100 W). The solution was then evaporated under vacuum, and the resulting oil was

2802
S. SERVI AND M. GENC
washed with water and dried. The crude product was purified by column chromato-
graphy on silica gel using 1:1 chloroform=methanol as eluent to give compound 3 in
60% yield.
N-(1H-Imidazoline-2-yl)-1H-benzimidazol-2-amine
(compound
3).
White powder, mp 249–252 ꢀC (ethanol); IR (KBr) tmax: 3398 (benzimidazole N-H
stretching), 3238 (N-H stretching), 3141 (imidazoline N-H stretching), 2856
(aliphatic C-H stretching), 1645 (C¼N stretching), 1615 (C¼C stretching), 1536
1
(N-H bending). H NMR (DMSO-d6, 300 MHz) d: 3.55 (s, 4H, imidazoline CH2),
6.86–7.16 (m, 4H, Ar-H), 7.83 (broad peak, 2H, imidazoline NH), 11.09 (s, 1H, ben-
zimidazole NH); it was made D2O exchange. 13C NMR (DMSO-d6, 75 MHz), d:
43.51, 113.48, 121.96, 139.51, 160.58, and 164.17. Anal. calcd. for C10H11N5
(201.23): C, 59.69; H, 5.51; N, 34.80, Found: C, 59.83; H, 5.75; N, 34.91.
N-(1H-Imidazoline-2-yl)-1H-benzimidazol-2-amine Derivatives:
(Compounds 4–10)
General procedure for synthesis of Mannich derivatives (compounds 4
and 5). A solution of compound 3 (0.995 mmol) in methanol (20 mL) was stirred at
room temperature for 2 h with aqueous formaldehyde (37%, 2.98 mmol) and
1.99 mmol secondary amine such as 2-methyl piperazine, 1-ethylpiperazine (d:
0.899 g cmꢁ3), and 4-methylpiperidine (d: 0.838 g cmꢁ3). The solvent was removed
on a rotary evaporator. The residue was mixed with methanol, and the precipitate
formed was filtered and then recrystallized from ethanol.
1-f(4-Methylpiperidin-1-yl)methylg-N-[1-(4-methylpiperidin-1-yl)methylg-
1H-imidazoline-2-yl]-1H-benzimidazol-2-amine (4). Yield 83%, yellow powder,
mp 162–164 ꢀC (ethanol); IR (KBr) tmax: 3224 (N-H stretching), 3047–3034 (C¼C-H
stretching), 2943–2784 (aliphatic C-H stretching), 1610 (C¼N stretching), 1597
(C¼C stretching), 1499 (N-H bending). 1H NMR (CHCl3-d, 300 MHz) d: 0.86
(d, 3H, J ¼ 4 Hz), 0.93 (d, 3H, J ¼ 4 Hz), 1.20 (m, 5H), 1.57 (m, 5H), 2.17–2.26
(m, 4H), 2.92 (d, 2H, J ¼ 12 Hz), 3.11(d, 2H, J ¼ 12 Hz), 3.61–3.69 (m, 4H), 4.17
(s, 2H), 4.96 (s, 2H), 7.04–7.42 (m, 4H, Ar-H), 8.98 (broad peak 1H), 13C NMR
(CHCl3-d, 75 MHz), d: 21.96, 30.04, 30.78, 31.41, 34.29, 46.8, 51.50, 51.70, 63.91,
67.31, 109.09, 115.93, 119.67, 120.60, 134.86, 141.71, 158.84, 160.58, Anal. calcd.
for C24H37N7 (423,60): C, 68.05; H, 8.80; N, 23.15. Found: C, 68.23; H, 8.93; N,
23.76.
1-f(4-Ethylpiperazin-1-yl)methylg-N-[1-f(4-ethylpiperazin-1-yl)methylg-
1H-imidazoline-2-yl]-1H-benzimidazol-2-amine (5). Yield 75%, oil; IR (KBr)
t
max: 3250 (N H stretching), 3051 (C¼C-H stretching), 2969–2850 (aliphatic C-H
stretching), 1618 (C¼C stretching), 1504 (N-H bending). 1H NMR (CHCl3-d,
300 MHz) d: 1.09–1.19 (m, 6H, CH3), 2.13–2.29 (m, 20 H piperazine CH2 and piper-
azin ring-N-CH2) 3.57–3.74 (m, 4H, imidazoline CH2), 4.18 (s, 2H imidazoline
ring-N-CH2-N) 4.91 (s, 2H benzimidazole ring -N-CH2-N) 6.98–7.44 (m, 4H,
Ar-H), 8.96 (broad peak 1H, NH), Anal. calcd. for C24H39N9 (453.63): C, 63.54;
H, 8.67; N, 27.79 Found: C, 63.60; H, 8.83; N, 27.96.

N-(1H-IMIDAZOLINE-2-YL)-1H-BENZIMIDAZOL-2-AMINE
2803
Synthesis of compound 6. A solution of 2-methylpiperidine (d: 0.844 g cmꢁ3
,
1.99mmol), aqueous formaldehyde, and concentrated hydrochloric acid (0.5 mL
HCl, 5 mL ethanol) in methanol (10 mL) was added to a solution of N-(1H-
Benzimidazole-2-yl)-N-(4,5-dihydro-1H-imidazol-2-yl) amine (0.995 mmol) in ethanol
(10 mL). The resulting solution was stirred at room temperature for 2 h. The solvent
was removed on a rotary evaporator. The residue was mixed with methanol, and the
precipitate formed was filtered and then recrystallized from ethanol.
N-(1H-imidazoline-2-yl)-1-f(2-methylpiperidin-1-yl)methylg-1H-benzimi-
dazol-2-amine hydrochloride (6). Yield 86%, white powder, mp 163–165 ꢀC (etha-
nol), IR (KBr) tmax: 3465 (þN-H stretching), 3241–3163 (N-H stretching), 3073
(C¼C-H stretching), 2948–2750 (aliphatic C-H stretching), 1634 (C¼Nþ stretching),
1597 (C¼C stretching), 1507 (N-H bending). 1H NMR (DMSO-d6, 300 MHz) d: 1.23
(d, 3H, CH3, J ¼ 6.6 Hz), 1.32–1.76 (m, 6H) 2.83–3.19 (m, 3H), 3.62–3.85 (m, 4H,
imidazoline CH2), 5.76 (s, 2H, N-CH2-N), 7.26–7.29 (m, 2H, Ar-H), 7.37–7.41(m,
2H, Ar-H), 8.62 (s, 1H, HCl), 8.71 (broad peak 1H, endocyclic NH), 9.11 (broad
peak 1H, exocyclic NH). Anal. calcd. for C17H25ClN6 (348,87): C, 58.53; H, 7.22;
N, 24.09, Found: C, 58.74; H, 7.44; N, 24.26.
Synthesis of compound 7. 1,4-Bis(bromomethyl) benzene (0.995 mmol) was
added dropwise to a mixture of N-(1H-benzimidazol-2-yl)-N-(4,5-dihydro-1H-
imidazol-2-yl) amine (0.2 g, 0.995 mmol) and finely powdered NaOH (0.004 g,
0.1 mmol) in DMSO (5 mL). The resulting solution was stirred at 35–40 ꢀC for 2 h.
Then water was added to the reaction mixture, and the solid that precipitated was
collected and crystallized from ethanol.
1-f4-(Bromomethyl)benzylg-N-(1H-imidazoline-2-yl)-1H-benzimidazol-
2-amine (7). Yield 78%, white powder, mp 175–177 ꢀC (ethanol); IR (KBr) tmax
:
3292–3275 (N-H stretching), 3051–3025 (C¼C-H stretching), 2922–2875 (aliphatic
C-H stretching), 1617 (C¼C stretching), 1501 (N-H bending). 1H NMR (DMSO-d6,
300 MHz) d: 3.52 (s, 4H, imidazoline CH2), 4.48 (m, 2H, CH2Br), 5.34 (m, 2H),
6.78–7.36 (m, 8H, Ar-H), 7.96 (s 1H, endocyclic NH), 8.74 (s 1H, exocyclic NH).
Anal. calcd. for C18H18BrN5 (384.27): C, 56.26; H, 4.72; N, 18.22. Found: C,
56.49; H, 4.63; N, 18.37.
Syntheses of compounds 8 and 9. 2-Chloro benzyl chloride (or allyl
bromide) (1.9 mmol) was added dropwise to a mixture of N-(1H-benzimidazol-2-
yl)-N-(4,5-dihydro-1H-imidazol-2-yl) amine (0.2 g, 0.995 mmol) and finely powdered
NaOH (0.158 g, 3.96 mmol) in DMSO (5 mL). The resulting solution was stirred at
35–40 ꢀC for 1 h. Then water was added to the reaction mixture, and the solid that pre-
cipitated was collected and recrystallized from ethanol.
1-(2-Chlorobenzyl)-N-(1-(2-chlorobenzyl)-1H-imidazoline-2-yl)-1H-benzi-
midazol-2-amine (8). Yield 90%, yellow powder, mp: 159–161 ꢀC (ethanol); IR
(KBr) tmax: 3224 (N-H stretching), 3060–3024 (C¼C-H stretching), 2935–2862 (ali-
phatic C-H stretching), 1608 (C¼N stretching), 1591 (C¼C stretching), 1499 (N-H
1
bending). H NMR (DMSO-d6, 400 MHz) d: 3.52 (m, 2H, imidazoline CH2), 3.73
(m, 2H, imidazoline CH2), 4.70 (s, 2H imidazoline ring-N-CH2-N), 5.50 (s, 2H ben-
zimidazole ring -N-CH2-N), 6.82–7.53 (m, 12H, Ar-H), 8.93 (broad peak 1H, NH).

2804
S. SERVI AND M. GENC
Anal. calcd. for C24H21Cl2N5 (450.36): C, 64.01; H, 4.70; N, 15.55, Found: C, 64.31;
H, 4.54; N, 15.78.
1-Allyl-N-(1-allyl-1H-imidazoline-2-yl)-1H-benzimidazol-2-amine (9). Yield
76%, yellow powder, mp: 60–62 ꢀC (CHCl3), IR (KBr) tmax: 3243 (N-H stretching),
3076–3041 (C¼C-H stretching), 2917–2881 (aliphatic C-H stretching), 1619 (C¼N
stretching), 1601 (C¼C stretching), 1498 (N-H bending). 1H NMR (CHCl3-d,
300 MHz) d: 3.45 (t, 2H, imidazoline CH2, J ¼ 8.4 Hz), 3.65 (t, 2H, imidazoline
CH2, J ¼ 7.2 Hz), 4.072 (d, 2H imidazoline ring-N-CH2, J ¼ 5.7 Hz), 4.81 (d, 2H ben-
zimidazole ring -N-CH2, J ¼ 6.0 Hz), 5.19 (m, 4H, allyl C¼CH2), 5.93 (m, 2H, allyl
C¼CH), 7.03–7.55 (m, 4H, Ar-H), 8.88 (broad peak 1H, NH); it was confirmed by
D2O exchange. Anal. calcd. for C16H19N5 (281.36): C, 68.30; H, 6.81; N, 24.89.
Found: C, 68.95; H, 7.13; N, 24.96.
Synthesis of Compound 10. N-(1H-Benzimidazol-2-yl)-N-(4,5-dihydro-1H-
imidazol-2-yl) amine (0.2 g, 0.995 mmol) was dissolved in 30 mL THF, and 0.28 mL
triethylamine (1.99 mmol) was added. The reaction mixture was stirred on an ice
bath for 0.5 h. thiophene-2-carbonyl chloride (1.99 mmol) was added dropwise over
a period of 10 min to the mixture, and the mixture was refluxed for 2 h. The solution
was then evaporated under vacuum to half its volume and poured into ice water,
resulting in a precipitate. The residue was filtered off and recrystallized from ethanol.
Thiophen-2-yl-[2-f1-(thiophene-2-carbonyl)-1H-benzimidazol-2-ylaminog-
1H-imidazoline-1-yl] methanone (10). Yield 73%, white powder, mp: 211–213 ꢀC
(ethanol); IR (KBr) tmax: 3193 (N-H stretching), 3025 (C¼C-H stretching),
2978–2857 (aliphatic C-H stretching), 1666 (C¼O stretching broader band), 1619
1
(C¼N stretching), 1595 (C¼C stretching), 1520 (N-H bending). H NMR (CHCl3-
d, 300 MHz) d: 3.85 (t, 2H, imidazoline CH2, J ¼ 7.2 Hz), 4.20 (t, 2H, imidazoline
CH2, J ¼ 7.5 Hz), 7.08–7.11 (m, 2H), 7.13–7.17 (m, 2H, Ar-H), 7.44–7.46 (m, 3H,
Ar-H), 7.62 (d, 2H, J ¼ 4.8 Hz, Ar-H), 7.93 (d, 2H, J ¼ 3.3 Hz, Ar-H). Anal. calcd.
for C20H15N5O2S2 (421.50): C, 56.99; H, 3.59; N, 16.62; S, 15.21. Found: C,
57.12; H, 3.72; N, 16.29; S, 15.65.
ACKNOWLEDGMENT
We are indebted to the Scientific and Technological Research Council of
Turkey (TUBITAK, Project Number 105T419).
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