Phenyliodine diacetate-mediated intramolecular C(sp2)-H amidation for 1,2-disubstituted benzimidazole synthesis under metal-free conditions

Article abstract of DOI:10.1002/adsc.201401110

A transition metal-free, hypervalent iodine(III) reagent [phenyliodine diacetate (PIDA)]-mediated C(sp²)-H amidation in trifluoroethanol (TFE) has been developed. The intramolecular coupling methodology presented here provides a direct access t

Full text of DOI:10.1002/adsc.201401110

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DOI: 10.1002/adsc.201401110
2
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Phenyliodine Diacetate-Mediated Intramolecular C(sp ) H
Amidation for 1,2-Disubstituted Benzimidazole Synthesis under
Metal-Free Conditions
Saikat Maitia and Prasenjit Mala,*
a
School of Chemical Sciences, National Institute of Science Education and Research (NISER) Bhubaneswar, Institute of
Physics Campus, PO Sainik School, Bhubaneswar, Odisha 751 005, India
Fax : (+91)-674-230-4036; phone: (+91)-674-230-4036; e-mail: pmal@niser.ac.in
Received: November 27, 2014; Revised: March 7, 2015; Published online: && &&, 0000
Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/adsc.201401110.
Abstract: A transition metal-free, hypervalent io- were performed in the open air and at ambient tem-
ACHTUNGTRENNUNGdine(III) reagent [phenyliodine diacetate (PIDA)]- perature, and were found to be eco-friendly and
2
À
mediated C(sp ) H amidation in trifluoroethanol atom-economical.
(TFE) has been developed. The intramolecular cou-
À
pling methodology presented here provides a direct Keywords: benzimidazole synthesis; C H amidation;
access to 1,2-disubstituted multifunctional benzimi- hypervalent iodine; metal-free synthesis; phenylio-
dazoles in good to excellent yields. The reactions dine diacetate (PIDA)
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Introduction
In Figure 1, examples of C(sp ) H amidation reac-
tions are shown. Zeng and co-workers developed the
Benzimidazole derivatives are prevalent in various Pd-catalyzed amidation of imines for substituted ben-
natural products and pharmaceuticals.[1] These bioac- zimidazoles[20] (Figure 1b). Driver and co-workers re-
tive molecules are known to have anti-infective.[2] ported an iron(II) bromide-catalyzed olefinic C H
À
anti-hepatitis B,[3] anti-depressant,[4] anti-HIV,[5] anti- functionalization of aryl azide to synthesize benzimi-
inflammatory,[6] anticancer,[7] and antitumour[8] activi- dazoles[21] (Figure 1c). Punniyamurthy and co-workers
ties, among others. The benzimidazole unit-containing demonstrated the use of the phenyl iodide–MCPBA
drug esomeprazole (Nexium) was one of the best-sell- (m-chloroperbenzoic acid) reagent for the synthesis of
ing drugs in 2009.[9] Therefore, the development of benzimidazoles[22] (Figure 1d).
metal-free, catalytic and chemoselective methodolo-
gies for benzimidazole synthesis is in great demand.
Common methods for benzimidazole synthesis in- Results and Discussion
volve the condensation of 1,2-phenylenediamine and
carbonyl compounds, followed by oxidation.[10] Select- Herein, we report
a
metal-free intramolecular
2
À
ed examples of recently used methodologies for ben- C(sp ) H amidation for the synthesis of 1,2-disubsti-
zimidazole synthesis are Cu(I)-catalyzed sequential tuted benzimidazoles.[9,23] Under our optimized condi-
three-component cascade reaction,[11] hydrogen bond- tions, phenyliodine diacetate (PIDA) or PhI(OAc)2
driven electrophilic activation,[12] heterogeneous palla- (reagent)[24] in TFE (2,2,2-trifluoroethanol, solvent,
dium-catalyzed hydrogen-transfer with primary Figure 1a) was used for the transformation. The reac-
amines,[13] Cu(II)-catalyzed N-arylation of amidines,[14] tions were complete within a few minutes (ca. 3–
Au-catalyzed reactions,[15] photocatalysis-mediated re- 30 min) at ambient temperature (278C) under aerobic
actions,[16] and Brønsted acid-catalyzed[17] reactions. conditions. This methodology is an example of
[19a,25]
À
À
These methodologies have disadvantages due to their a metal-free C N bond construction
via C H ac-
hazardous reaction conditions, use of expensive re- tivation using hypervalent iodine(III) reagents.[26]
agents and poor atom economy. In addition, hyperva-
The reaction conditions were optimized based on
the screening of various oxidants, the results of which
has are shown in Table 1. The compound (E)-N-{2-[(2-
bromobenzylidene)amino]phenyl}-4-methylbenzene-
[18]
À
lent iodine(III)-mediated C N bond formation
through intramolecular C(sp ) H amination
become popular recently.
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Table 1. Optimization of the reaction conditions.
Entry Oxidant
Solvent
Time [h] Yield [%]
1
2
3
4
5
6
7
8
PIDA
PIDA
HFIP
AcOH
6 h
6 h
8 h
8 h
64
70
44
53
31
0
PhI–MCPBA HFIP
PhI–MCPBA TFE
PhI–MCPBA solvent-free[a] 6 h
MCPBA
Oxone[b]
Oxone
PIDA
PIDA
PIDA
PIFA
PIDA
PIDA
PIDA
DCM
CH3CN
H2O
CH3CN
EtOEt
MeOH
TFE
12 h
12 h
12 h
12 h
12 h
12 h
15 min
12 h
12 h
0
0
9
11
18
60
50
0
10
11
12
13
14
15
16
17
18
DMF
DMSO
DCM
TFE
CH3CN–H2O 12 h
TFE 12 h
0
30 min
5 min
91
>98
0
PIDA
PhI–Oxone
PhI–H2O2
0
2
À
Figure 1. Examples of C(sp ) H amidation for benzimida-
zole synthesis. The newly formed bond is shown as a thick
line: a) our approach; b) Zengꢁs report on Pd-catalyzed ami-
[a]
Reactions were performed under solvent-free ball milling
conditions.
Oxone is 2KHSO5·KHSO4·K2SO4.
[b]
dation;[20] c) Iron(II) bromide-catalyzed olefinic C H func-
À
tionalization of aryl azide by Driver;[21] d) Punniyamurthyꢁs
approach using PhI–MCPBA.[22]
result. As anticipated, TFE, which is polar and non-
nucleophilic in nature, appears to be the most suitable
sulfonamide (1a) was used as a model substrate, solvent for the reaction.[28]
which was prepared following a previous literature
Using similar conditions as for the 1a to 2a transfor-
report.[20] The most appropriate conditions were iden- mation (Table 1), 1,2-disubstituted benzimidazole de-
tified when the reaction was performed for 1a (0.2M rivatives were obtained in very good to excellent
in TFE) using PIDA (1.1 equivalent) in TFE. The yields (Figure 2). A few examples of substitutions at
product 2-(2-bromophenyl)-1-tosyl-1H-benzo[d]imida- the 2-position of benzimidazole are tolyl (2b), 4-fluo-
zole (2a) was isolated in quantitative (>98%) yield rophenyl (2e), 3,5-dicyanomesityl (2g), anisyl (2h),
within 5 min at room temperature (Table 1, entry 16). perfluorophenyl (2m), anthryl (2m), pyridyl (2p), pyr-
PIDA is also recognized as a superior oxidant to the enyl (2r), 3-quinolinyl (2s) and 5-nitrofurfuryl (2t).
following oxidants: PhI (phenyliodide)–MCPBA (m-
The proposed methodology for the synthesis of
chloroperbenzoic acid) (entries 3-5), oxone benzimidazole derivatives with various aromatic sys-
(2KHSO5·KHSO4·K2SO4) (entries 7 and 8), PIFA tems was found to be efficient and convenient. The
[phenyliodine bis(trifluoroacetate)] (entry 12), PhI– scope of substrates for this methodology was further
oxone (entry 17), PhI–hydrogen peroxide (entry 18), explored, and the results are presented in Figure 3. In
etc. Subsequently, TFE was found to be a more ap- all the cases, the reactions were completed within
propriate solvent than HFIP (hexafluoroisopropyl al- 30 min. The benzimidazole derivatives with aliphatic
cohol) (entry 1), TFA (trifluoroacetic acid) (entry 2), substitutions at the 2-position were obtained in mod-
acetonitrile (entry 9), ethyl acetate (entry 10), metha- erate yields (Figure 3a). The results for the synthesis
nol (entry 11) and DCM (dichloromethane) of core-substituted benzimidazoles are shown in Fig-
(entry 15). However, no product was obtained with ure 3b. Good yields were obtained for carboxylic acid
solvents such as DMF (dimethylformamide) (2bb), naphthalene (2bc) and ortho-xylyl (2be) deriva-
(entry 13) and DMSO (dimethyl sulfoxide) (entry 14). tives. Conversely, nitro (2ba) and dichloro (2bf) deriv-
The reaction was performed under solvent-free ball atives gave very poor yields (Figure 3b). Likewise,
milling conditions[27] which did not render a favourable substitution at the 1-position or N(sp3) of benzimida-
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Phenyliodine Diacetate-Mediated Intramolecular C(sp ) H Amidation
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Figure 3. The substrate scope for our C(sp ) H amidation
methodology for benzimidazoles: a) 2-substituted benzimi-
dazoles with aliphatic substitutions; b) core-modified benz-
AHCTUNGTREGUNiNN midazoles; c) 1-substituted benzimidazoles.
X-ray crystal structure investigations were carried
out for the synthesized compounds. Good-quality
crystals were obtained after slow evaporation of the
solvent from an ethyl acetate solution. The structures
of compounds 2a and 2aa are shown in Figure 4.
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2
In Scheme 1, a plausible mechanism for the C(sp )
À
Figure 2. Results of the C(sp ) H amidation using PIDA in
H amidation reaction is described. Two possible path-
ways (path A or path B) were initially rationalized. In
path A, the N(sp3) of the amide unit was expected to
coordinate with the iodide atom of PIDA. This causes
TFE. Examples of 2-substituted benzimidazoles are present-
ed.
zole was also performed (Figure 3c). Products from loss of one molecule of acetic acid and intermediate 3
benzenesulfonyl- (2ca and 2cb) and benzoyl-substitut- was generated.[24f] However, in path B, we assumed
ed benzimidazole derivatives (2cc) were successfully that the nitrenium intermediate 4 was formed via co-
isolated with good yields.
ordination of the imine N(sp2) and iodonium cation
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Table 2. Standardization of the metal-free conditions.
Entry PIDA
Reference Pd[c] [ppm]
1
2
3
4
5
6
A (Sigma–Aldrich; 98%)[a]
–
1.2
A and then recrystallization
PhI–K2S2O8–AcOH
PhI–MCPBA–AcOH
PhI–NaBO3–AcOH
A+500 ppm Pd[b]
–
<0.1
0.13
<0.1
0
[31]
[32]
[33]
Figure 4. a) X-ray structures of a) 2a and b) 2aa.
~500
[a]
[b]
[c]
PIDA was used as received from commercial source.
Pd(OAc)2 was added externally before the reaction.
No Pd impurity was found from the solvent (TFE).
were observed for benzimidazoles with electron-with-
drawing (2ba nitro and 2bf chloro) substituents at the
4-position with respect to N(sp2). This is possibly due
to the formation of intermediate 3 via path A.
Furthermore, we demonstrated that the presence of
Pd was not necessary for the transformation. Induc-
tively coupled plasma optical emission spectrometry
(ICP-OES) analysis was performed for both TFE (sol-
vent) and PIDA (reagent). The yield and reaction
time were standardized for the conversion of 1o to 2o
(Table 2). No Pd impurity was detected in either the
TFE or PIDA synthesized by following the PhI–
NaBO3–AcOH[33] method. However, some of the
PIDA samples had trace amounts (ca. 0.1–1.2 ppm) of
a Pd impurity (Table 2). Interestingly, the efficiency
of the reaction was unaffected by using PIDA with no
Pd (entry 5), by trace impurities (entries 1–4) and in
the presence of 500 ppm of externally added Pd
(entry 6).
2
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Scheme 1. Plausible mechanism for the C(sp ) H amidation
reaction.
Conclusions
(from PIDA). Subsequently, 5 was generated from
either 3 or 4. Finally, the acetate anion could abstract In summary, we have developed a mild and efficient
one proton from 5 to yield 2. method for the synthesis of substituted benzimida-
A comparison was performed between path A and zoles. This methodology was found to be compatible
path B[29] to understand the mechanism of the reac- with a wide range of functional groups and requires
tion. In path B for the transformation of 4 to 5, the easily accessible starting materials. The coupling reac-
expected reaction was as follows: three-membered tion is a representative demonstration of metal-free
2
À
ring opening after nucleophilic attack by amide N- C(sp ) H amidation. Additionally, performing the re-
atom, followed by reductive elimination of iodoben- actions in the open atmosphere and at room tempera-
zene. Moreover, during nucleophilic addition, attack- ture over smaller reaction times using metal-free con-
ing through the amide O-center would be another ditions may be considered as an example of eco-
possibility.[30] However, because benzimidazole deriva- friendly methodology. This methodology could also
tives are the only products formed, the possibility of be useful in constructing a library of benzimidazoles
path B could be ruled out. Relatively poor yields under metal-free conditions, which would be desirable
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Phenyliodine Diacetate-Mediated Intramolecular C(sp ) H Amidation
mp 154–1568C (no literature report on melting points); IR
for medicinal/pharmaceutical chemistry and drug dis-
covery efforts.
˜
(KBr): n=2923, 2363, 1647, 1447, 1381, 1307, 1283, 1251,
1189, 1177, 1126, 1087, 1047 cmÀ1 1H NMR (400 MHz,
;
CDCl3): d=8.16 (d, J=8 Hz, 1H), 7.79 (d, J=8 Hz, 1H),
7.66 (d, J=8 Hz, 1H), 7.54 (d, J=8 Hz, 2H), 7.49–7.39 (m,
5H), 7.20 (d, J=8 Hz, 2H), 2.37 (s, 3H); 13C NMR
(100 MHz, CDCl3): d=150.7, 146.1, 142.2, 135.1, 132.8,
132.6, 132.5, 132.1, 131.7, 130.0, 127.6, 126.5, 125.8, 125.1,
124.8, 120.9, 114.3, 21.8; HR-MS (ESI-TOF); m/z=
427.0129, calculated for C20H15SN2O2Br (M+H+): 427.0110.
2-(ortho-Tolyl)-1-tosyl-1H-benzo[d]imidazole (2b): Yield:
77%; Rf =0.5 (hexane:ethyl acetate 4:1); white solid; mp
Experimental Section
General Methods
Column chromatographic purifications of the compounds
were performed using silica gel (mesh 100–200) and hexane-
ethyl acetate mixtures as eluent, unless otherwise specified.
NMR spectra were recorded on a 400 MHz instrument at
258C. The chemical shift values are reported in parts per
million (ppm) with respect to residual chloroform (7.26 ppm
for 1H and 77.16 for 13C). High-resolution mass spectra
(HR-MS) were recorded on an ESI-TOF (time of flight)
mass spectrometer. Infrared spectral data are reported in
wave number (cmÀ1). Melting points of the compounds were
determined using a digital melting point apparatus and are
uncorrected. X-Ray diffraction data for single crystals of 2a
˜
132–1348C; IR (KBr): n=3063, 2361, 1594, 1539, 1448,
1380, 1300, 1252, 1230, 1177, 1123, 1072 cmÀ1 1H NMR
;
(400 MHz, CDCl3): d=8.27 (d, J=8 Hz, 1H), 7.80 (d, J=
8 Hz, 1H), 7.52–7.43 (m, 5H), 7.31–7.28 (m, 2H), 7.23–7.18
(m, 3H), 2.41 (s, 3H), 2.09 (s, 3H); 13C NMR (100 MHz,
CDCl3): d=152.5, 145.9, 142.4, 139.1, 135.4, 133.3, 130.8,
130.4, 130.0, 129.9, 129.8, 127.4, 125.5, 125.0, 124.9, 120.5,
114.5, 21.8, 20.0; HR:MS (ESI-TOF): m/z=363.1175, calcu-
lated for C21H18N2O2S (M+H+): 363.1162.
and 2aa were collected using
a CCD diffractometer
equipped with an APEX II detector with graphite-mono-
chromatized Mo-Ka (l=0.71073 ꢂ) radiation at 300 K. The
structures were solved by direct method using SHELLX-97.
CCDC 1032667 (2a) and CCDC 1032666 (2aa) contain the
supplementary crystallographic data for this paper.
These data can be obtained free of charge from
The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif. FT-IR spectra were re-
corded after making thin layer of the compounds on the sur-
face of NaCl crystal using dichloromethane. Inductively cou-
pled plasma optical emission spectrometry (ICP-OES) anal-
yses were performed on a Perkin–Elmer Optima 2100 DV
instrument.
2-(4-Isopropylphenyl)-1-tosyl-1H-benzo[d]imidazole (2c):
Yield: 87%; Rf =0.5 (hexane:ethyl acetate 4:1); white solid;
mp 135–1378C; IR (KBr): n˜ =2961, 2361, 1596, 1495, 1449,
1381, 1304, 1272, 1254, 1189, 1177, 1121, 1076, 1011 cmÀ1
;
1H NMR (400 MHz, CDCl3): d=8.19 (d, J=8 Hz, 1H), 7.71
(d, J=8 Hz, 1H), 7.54 (d, J=12 Hz, 2H), 7.42–7.28 (m,
6H), 7.07 (d, J=8 Hz, 2H), 3.01 (sept, J=8 Hz, 1H), 2.32
(s, 3H), 1.32 (d, J=8 Hz, 6H); 13C NMR (100 MHz, CDCl3):
d=154.5, 151.7, 145.6, 142.8, 135.1, 134.0, 131.0, 129.7, 127.9,
127.1, 125.9, 125.4, 125.3, 120.4, 115.3, 34.2, 24.0, 21.7; HR-
MS (ESI-TOF): m/z=391.1486, calculated for C23H22N2O2S
(M+H+): 391.1475.
2-(3-Bromo-4-methoxyphenyl)-1-tosyl-1H-benzo[d]imida-
zole (2d): Yield: 97%; Rf =0.4 (hexane:ethyl acetate 4:1);
˜
white solid; mp 146–1488C; IR (KBr): n=2938, 2361, 1609,
General Procedure for Preparation of N-Substituted
Benzimidazoles
1597, 1485, 1450, 1380, 1293, 1269, 1189, 1177, 1121, 1083,
1053, 1015 cmÀ1 1H NMR (400 MHz, CDCl3): d=8.19 (d,
;
J=8 Hz, 1H), 7.71 (d, J=7.3 Hz, 1H), 7.68–7.63 (m, 2H),
7.46–7.36 (m, 2H), 7.33 (d, J=8 Hz, 2H), 7.13 (d, J=8 Hz,
2H), 7.00 (d, J=8 Hz, 1H), 4.00 (s, 3H), 2.34 (s, 3H);
13C NMR (100 MHz, CDCl3): d=157.7, 152.6, 146.0, 142.6,
135.3, 135.0, 134.0, 131.9, 129.9, 127.0, 125.6, 125.5, 123.5,
120.4, 115.3, 110.9, 110.8, 56.5, 21.7; HR-MS (ESI-TOF):
m/z=457.0199, calculated for C21H17BrN2O3S (M+H+):
457.0216.
To the solution of imine 1 (0.5 mmol, 1.0 equiv.) in TFE
(0.5 mL) was added PIDA (0.55 mmol, 1.1 equiv.) under the
open atmosphere. The reaction mixture was stirred at room
temperature (278C). The progress of the reaction was moni-
tored by TLC using ethyl acetate and hexane as eluent.
After complete consumption of the reactant the resulting so-
lution was evaporated to dryness. The resulting residue was
purified on silica gel column chromatography using n-
hexane and ethyl acetate as eluent.
2-(4-Fluorophenyl)-1-tosyl-1H-benzo[d]imidazole
(2e):
Yield: 94%; Rf =0.5 (hexane:ethyl acetate 4:1); white solid;
˜
mp 118–1208C; IR (KBr): n=2923, 2364, 1596, 1494, 1450,
Procedure for Preparation of 2-(2-Bromophenyl)-1-
1305, 1272, 1229, 1190, 1177, 1159, 1122, 1074, 1012 cmÀ1
;
tosyl-1H-benzo[d]imidazole (2a)[34]
1H NMR (400 MHz, CDCl3): d=8.20 (d, J=8 Hz, 1H), 7.72
(d, J=8 Hz, 1H), 7.62 (dd, J1 =8 Hz, J2 =4 Hz, 2H), 7.46–
7.38 (m, 2H), 732 (d, J=12 Hz, 2H), 7.18–7.10 (m, 4H),
2.33 (s, 3H); 13C NMR (100 MHz, CDCl3): d=164.3 (d,
1JC,F =249.9 Hz), 153.2, 146.0, 142.7, 135.0, 134.0, 132.7 (d,
3JC,F =8.7 Hz), 129.9, 127.0, 126.2 (d, 4JC,F =3.4 Hz), 125.7,
125.5, 120.5, 115.3, 115.1 (d, 2JC,F =21.8 Hz), 21.7; HR-MS
(ESI-TOF): m/z=367.0904, calculated for C20H15N2O2SF
(M+H+): 367.0911.
To a stirred solution of (E)-N-{2-[(2-bromobenzylidene)ami-
no]phenyl}-4-methylbenzenesulfonamide
1a
(0.5 mmol,
1.0 equiv) in TFE (0.5 mL) was added PIDA (0.55 mmol,
1.1 equiv.) at room temperature. The progress of the reac-
tion was monitored by TLC using ethyl acetate and hexane
as eluent. After complete consumption of the reactant the
resulting solution was evaporated to dryness. The resulting
residue was purified on silica gel column chromatography
using n-hexane and ethyl acetate as eluent to isolate 2-(2-
bromophenyl)-1-tosyl-1H-benzo[d]imidazole (2a); yield:
quantitative. Rf =0.5 (hexane:ethyl acetate 4:1); white solid;
3-Bromo-2,4,6-trimethyl-5-(1-tosyl-1H-benzo[d]imidazol-
2-yl)benzonitrile (2f): Yield: 86%; Rf =0.5 (hexane:ethyl
acetate 4:1); white solid; mp 195–1978C; IR (KBr): n=
˜
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1
2923, 2361, 2219, 1592, 1447, 1385, 1265, 1250, 1177, 1147,
1159, 1092, 1079 cmÀ1; H NMR (400 MHz, CDCl3): d=8.17
(d, J=8 Hz, 1H), 7.77 (d, J=4 Hz, 1H), 7.52 (d, J=8 Hz,
2H), 7.42–7.38 (m, 2H), 7.18 (d, J=8 Hz, 2H), 6.40 (s, 1H),
6.27 (s, 1H), 3.87 (s, 3H), 3.44 (s, 3H), 2.37 (s, 3H), 1.92 (s,
3H); 13C NMR (100 MHz, CDCl3): d=162.2, 159.9, 149.7,
145.4, 142.6, 141.7, 135.7, 133.4, 129.6, 127.6, 125.0, 124.4,
120.5, 114.1, 112.0, 106.1, 95.5, 55.4, 55.2, 21.7, 20.2; HR-MS
(ESI-TOF): m/z=423.1367, calculated for C23H22N2O4S
(M+H+): 423.1373.
1
1089, 1048, 1000 cmÀ1; H NMR (400 MHz, CDCl3): d=8.30
(d, J=8 Hz, 1H), 7.82 (d, J=8 Hz, 1H), 7.55 (t, J=7.4 Hz,
1H), 7.51–7.46 (m, 3H), 7.29 (d, J=4 Hz, 2H), 2.81 (s, 3H),
2.46 (s, 3H), 1.92 (s, 3H), 1.91 (s, 3H); 13C NMR (100 MHz,
CDCl3): d=148.9, 146.8, 144.6, 143.9, 142.0, 134.9, 132.9,
130.2, 130.1, 127.6, 126.1, 125.9, 125.2, 120.9, 116.7, 114.2,
112.9, 23.6, 23.1, 21.9, 19.4; HR-MS (ESI-TOF): m/z=
494.0531, calculated for C24H20N3O2SBr (M+H+): 494.0532.
2,4,6-Trimethyl-5-(1-tosyl-1H-benzo[d]imidazol-2-yl)iso-
phthalonitrile (2g): Yield: 89%; Rf =0.5 (hexane:ethyl ace-
4-(1-Tosyl-1H-benzo[d]imidazol-2-yl)benzonitrile
Yield: 92%; Rf =0.4 (hexane:ethyl acetate 4:1); white solid;
(2l):
˜
˜
tate 4:1); white solid; mp 214–2168C; IR (KBr): n=2923,
mp 146–1488C; IR (KBr): n=2918, 2356, 2229, 1596, 1492,
2360, 2224, 1447, 1384, 1316, 1253, 1173, 1121, 1089, 1050,
1448, 1382, 1306, 1274, 1253, 1190, 1176, 1122, 1080,
1
814, 749 cmÀ1; H NMR (400 MHz, CDCl3): d=8.26 (d, J=
1012 cmÀ1 1H NMR (400 MHz, CDCl3): d=8.19 (d, J=
;
8 Hz, 1H), 7.80 (d, J=8 Hz, 1H), 7.55 (t, J=7.5 Hz, 1H),
7.50–7.45 (m, 3H), 7.27 (d, J=8 Hz, 1H), 2.87 (s, 3H), 2.44
(s, 3H), 2.03 (s, 6H); 13C NMR (100 MHz, CDCl3): d=
147.8, 147.8, 147.3, 147.2, 142.1, 134.8, 132.9, 130.7, 130.3,
127.4, 126.4, 125.4, 121.0, 115.4, 114.2, 113.5, 21.9, 20.6, 20.1;
HR-MS (ESI-TOF): m/z=441.1423, calculated for
C25H20N4O2S (M+H+): 441.1380.
8 Hz, 1H), 7.77–7.73 (m, 5H), 7.50–7.40 (m, 2H), 7.34 (d,
J=8 Hz, 2H), 7.13 (d, J=8 Hz, 2H), 2.34 (s, 3H); 13C NMR
(100 MHz, CDCl3): d=152.0, 146.3, 142.7, 134.8, 134.6,
133.9, 131.6, 131.5, 130.0, 126.9, 126.3, 125.8, 120.8, 118.3,
115.2, 114.3, 21.7; HR-MS (ESI-TOF): m/z=374.0964, calcu-
lated for C21H15N3O2S (M+H+): 374.0958.
2-(Perfluorophenyl)-1-tosyl-1H-benzo[d]imidazole (2m):
Yield: 91%; Rf =0.6 (hexane:ethyl acetate 4:1); white solid;
2-(4-Methoxyphenyl)-1-tosyl-1H-benzo[d]imidazole (2h):
Yield: 92%; Rf =0.5 (hexane:ethyl acetate 4:1); white solid;
˜
mp 103–1058C; IR (KBr): n=2924, 2360, 1594, 1505, 1449,
mp 113–1168C; IR (KBr): n=2942, 2555, 2226, 1579, 1543,
1386, 1337, 1242, 1190, 1177, 1123, 1088, 1043, 993 cmÀ1
;
˜
1495, 1450, 1380, 1336, 1304, 1273, 1227, 1152, 1075,
1H NMR (400 MHz, CDCl3): d=8.06 (d, J=8 Hz, 1H), 7.81
(d, J=8 Hz, 1H), 7.62 (d, J=8 Hz, 2H), 7.52–7.42 (m, 2H),
7.27 (d, J=8 Hz, 2H), 2.39 (s, 3H); 13C NMR (100 MHz,
CDCl3): d=147.0 (m), 146.8, 144.4 (m), 142.7, 141.9 (m),
138.6 (m), 136.4 (m), 134.5, 132.9, 130.3, 127.1, 126.7, 125.5,
121.3, 114.1, 106.9 (m), 21.7; HR-MS (ESI-TOF): m/z=
439.0537, calculated for C20H11N2O2SF5 (M+H+): 439.0534.
1029 cmÀ1 1H NMR (400 MHz, CDCl3): d=8.19 (d, J=
;
8 Hz, 1H), 7.69 (d, J=8 Hz, 1H), 7.59 (d, J=8 Hz, 2H),
7.43–7.34 (m, 2H), 7.30 (d, J=8 Hz, 2H), 7.07 (d, J=8 Hz,
2H), 6.98 (d, J=8 Hz, 2H), 3.89 (s, 3H), 2.29 (s, 3H);
13C NMR (100 MHz, CDCl3): d=161.5, 154.4, 145.6, 142.8,
135.0, 134.0, 132.6, 129.7, 127.0, 125.3, 125.2, 122.2, 120.2,
115.4, 113.2, 55.4, 21.6; HR-MS (ESI-TOF): m/z=379.1132,
calculated for C21H18N2O3S (M+H+): 379.1111.
2-(3-Chlorophenyl)-1-tosyl-1H-benzo[d]imidazole
(2n):
Yield: 91%; Rf =0.7 (hexane:ethyl acetate 4:1); white solid;
˜
2-Mesityl-1-tosyl-1H-benzo[d]imidazole (2i): Yield: 86%;
Rf =0.6 (hexane:ethyl acetate 4:1); white solid; mp 145–
mp 100–1018C; IR (KBr): n=2922, 2360, 1594, 1537, 1449,
1382, 1307, 1272, 1252, 1189, 1177, 1123, 1085, 1032,
˜
1478C; IR (KBr): n=2918, 2361, 1594, 1541, 1449, 1383,
1009 cmÀ1 1H NMR (400 MHz, CDCl3): d=8.20 (d, J=
;
1252, 1228, 1190, 1178, 1121, 1091, 1066, 1013 cmÀ1
;
8 Hz, 1H), 7.73 (d, J=8 Hz, 1H), 7.56–7.49 (m, 3H), 7.47–
7.38 (m, 3H), 7.36 (d, J=8 Hz, 2H), 7.13 (d, J=8 Hz, 2H),
2.33 (s, 3H); 13C NMR (100 MHz, CDCl3): d=152.3, 146.1,
142.5, 134.9, 133.9, 133.7, 131.8, 130.6, 129.9, 129.2, 129.0,
127.0, 125.8, 125.4, 120.6, 115.1, 21.7; HR-MS (ESI-TOF):
m/z=383.0640, calculated for C20H15ClN2O2S (M+H+):
383.0616.
2-(Anthracen-9-yl)-1-tosyl-1H-benzo[d]imidazole
Yield: 90%; Rf =0.45 (hexane:ethyl acetate 4:1); yellow
solid; mp 195–1978C; IR (KBr): n=2918, 2356, 1595, 1535,
1H NMR (400 MHz, CDCl3): d=8.27 (d, J=8 Hz, 1H), 7.77
(d, J=8 Hz, 1H), 7.48–7.41 (m, 4H), 7.18 (d, J=8 Hz, 2H),
6.88 (s, 2H), 2.39 (s, 3H), 2.37 (s, 3H) 1.76 (s, 6H);
13C NMR (100 MHz, CDCl3): d=151.9, 146.0, 142.3, 139.9,
138.8, 135.3, 133.2, 129.8, 127.9, 127.8, 126.9, 125.2, 124.6,
120.5, 114.2, 21.8, 21.5, 20.0; HR-MS (ESI-TOF): m/z=
391.1484, calculated for C23H22N2O2S (M+H+): 391.1475.
2-(2-Bromo-5-fluorophenyl)-1-tosyl-1H-benzo[d]imida-
zole (2j): Yield: 96%; Rf =0.5 (hexane:ethyl acetate 4:1);
(2o):
˜
˜
white solid; mp 94–968C; IR (KBr): n=3063, 2361, 1596,
1448, 1379, 1346, 1254, 1233, 1175, 1146, 1088, 1044,
1578, 1542, 1463, 1448, 1384, 1308, 1288, 1245, 1188, 1175,
1014 cmÀ1 1H NMR (400 MHz, CDCl3): d=8.64 (s, 1H),
;
1127, 1088, 1045, 1022 cmÀ1
;
1H NMR (400 MHz, CDCl3):
8.37 (d, J=8 Hz, 1H), 8.05 (d, J=12 Hz, 2H), 7.92 (d, J=
8 Hz, 1H), 7.60–7.50 (m, 2H), 7.45–7.41 (m, 2H), 7.24–7.18
(m, 4H), 6.98 (d, J=8 Hz, 2H), 6.77 (d, J=8 Hz, 2H), 2.23
(s, 3H); 13C NMR (100 MHz, CDCl3): d=150.3, 145.6, 142.5,
134.4, 133.6, 131.9, 130.8, 130.3, 130.0, 129.4, 128.5, 127.4,
127.1, 126.6, 125.7, 125.7, 125.3, 125.1, 125.0, 123.6, 120.8,
114.4, 21.6; HR-MS (ESI-TOF): m/z=449.1309, calculated
for C28H20N2O2S (M+H+): 449.1318.
d=8.18 (d, J=8 Hz, 1H), 7.82 (d, J=8 Hz, 1H), 7.66–7.60
(m, 3H), 7.52–7.43 (m, 2H), 7.24–7.20 (m, 2H), 7.19–7.12
(m, 2H), 2.39 (s, 3H); 13C NMR (100 MHz, CDCl3): d=
1
160.9 (d, JC,F =247.1 Hz), 149.4, 146.4, 142.1, 135.0, 134.0 (d,
3JC,F =8 Hz), 133.7 (d, 3JC,F =8.4 Hz), 132.7, 130.1, 127.4,
2
4
126.0, 125.2, 120.9, 119.7 (d, JC,F =24 Hz), 119.3 (d, JC,F
=
3.6 Hz), 119.0 (d, 2JC,F =22 Hz), 114.2, 21.7; HR-MS (ESI-
TOF): m/z=445.0021, calculated for C20H14N2O2SBrF (M+
H+): 445.0016.
2-(Pyridin-2-yl)-1-tosyl-1H-benzo[d]imidazole (2p): Yield:
69%; Rf =0.4 (hexane:ethyl acetate 7:3); white solid; mp
˜
2-(2,4-Dimethoxy-6-methylphenyl)-1-tosyl-1H-benzo[d]-
imidazole (2k): Yield: 77%; Rf =0.4 (hexane:ethyl acetate
129–1318C; IR (KBr): n=3050, 2360, 1592, 14448, 1434,
1
1375, 1316, 1254, 1189, 1177, 1128, 1087, 790 cmÀ1; H NMR
˜
7:3); white solid; mp 178–1808C; IR (KBr): n=2964, 2363,
(400 MHz, CDCl3): d=8.68 (d, J=4 Hz, 1H), 8.09–8.01 (m,
1611, 1450, 1379, 1337, 1298, 1253, 1230, 1202, 1189, 1176,
3H), 7.86–7.78 (m, 3H), 7.46–7.40 (m, 3H), 7.39–7.28 (m,
6
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ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Adv. Synth. Catal. 0000, 000, 0 – 0
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FULL PAPERS
Phenyliodine Diacetate-Mediated Intramolecular C(sp ) H Amidation
2H), 2.38 (s, 3H); 13C NMR (100 MHz, CDCl3): d=151.7,
149.7, 148.5, 145.6, 142.3, 136.4, 135.8, 133.6, 129.7, 127.9,
125.8, 125.5, 125.0, 124.7, 120.9, 114.4, 21.7; HR-MS (ESI-
TOF): m/z=350.0971, calculated for C19H15N3O2S (M+H+):
350.0958.
7.66 (m, 1H), 7.35–7.31 (m, 2H), 7.27 (d, J=8 Hz, 2H),
3.52–3.45 (m, 1H), 2.38 (s, 3H), 1.94–1.84 (m, 4H), 1.75–
1.61 (m, 3H), 1.44–1.34 (m, 3H); 13C NMR (100 MHz,
CDCl3): d=159.8, 145.9, 136.0, 133.0, 130.3, 126.7, 124.8,
124.7, 119.9, 114.1, 38.2, 32.7, 26.4, 25.9, 21.8, 0.1; HR-MS
(ESI-TOF): m/z=355.1484, calculated for C20H22N2O2S
(M+H+): 355.1475.
2-(Naphthalen-1-yl)-1-tosyl-1H-benzo[d]imidazole (2q):
Yield: 84%; Rf =0.5 (hexane:ethyl acetate 4:1); white solid;
1-Tosyl-1H-benzo[d]imidazole (2ab):[35] Yield: 44%; Rf =
0.6 (hexane:ethyl acetate 4:1); white solid; mp 84–868C (lit.
˜
mp 116–1188C; IR (KBr) n=3050, 2356, 1595, 1537, 1448,
1379, 1301, 1278, 1254, 1230, 1188, 1175, 1133, 1088, 1042,
1014 cmÀ1 1H NMR (400 MHz, CDCl3): d=8.30 (d, J=
;
˜
85–868C); IR (KBr): n=2920, 2359, 1603, 1381, 1254, 1160,
1088 cmÀ1 1H NMR (400 MHz, CDCl3): d=8.43 (s, 1H),
;
8 Hz, 1H), 8.03 (d, J=8 Hz, 1H), 7.87 (d, J=8 Hz, 1H),
7.83 (d, J=8 Hz, 1H), 7.61–7.57 (m, 2H), 7.51–7.44 (m,
3H), 7.28–7.23 (m, 2H), 7.19 (d, J=8 Hz, 2H), 6.88 (d, J=
8 Hz, 2H), 2.22 (s, 3H); 13C NMR (100 MHz, CDCl3): d=
151.5, 145.7, 142.4, 134.9, 133.6, 133.1, 132.5, 130.9, 130.1,
129.5, 128.2, 127.3, 126.8, 126.0, 125.6, 125.3, 125.1, 124.4,
120.6, 114.7, 21.6; HR-MS (ESI-TOF): m/z=399.1199, cal-
culated for C24H18N2O2S (M+H+): 399.1162.
7.89–7.85 (m, 3H), 7.77 (d, J=4 Hz, 1H), 7.42–7.38 (m,
2H), 7.36–7.30 (m, 2H), 2.38 (s, 3H); 13C NMR (100 MHz,
CDCl3): d=146.3, 144.1, 141.3, 134.7, 130.9, 130.4, 127.4,
125.7, 124.9, 121.2, 112.6, 21.8; HR-MS (ESI-TOF): m/z=
273.0692, calculated for C14H12N2O2S (M+H+): 273.0692.
2-(2-Phenylpropyl)-1-tosyl-1H-benzo[d]imidazole (2ac):
Yield: 57%; Rf =0.5 (hexane:ethyl acetate 4:1); colourless
2-(Pyren-1-yl)-1-tosyl-1H-benzo[d]imidazole (2r): Yield:
76%; Rf =0.45 (hexane:ethyl acetate 4:1); white solid; mp
˜
oil; IR (KBr): n=2963, 2925, 2356, 1597, 1545, 1451, 1376,
1253, 1228, 1168, 1149, 1120, 1089, 1043, 1015 cmÀ1
;
˜
1H NMR (400 MHz, CDCl3): d=8.05–8.03 (m, 1H), 7.73–
7.70 (m, 3H), 7.37–7.30 (m, 6H), 7.25–7.21 (m, 3H), 3.74–
3.65 (m, 1H), 3.55–3.50 (m 1H), 3.44–3.38 (m, 1H), 2.35 (s,
3H), 1.36 (d, J=8 Hz, 3H).; 13C NMR (100 MHz, CDCl3):
d=153.8, 146.3, 145.8, 142.1, 135.5, 133.1, 130.2, 128.6,
127.0,126.7, 126.4, 124.8, 124.7, 119.9, 113.8, 38.5, 38.3, 21.6,
21.1; HR-MS (ESI-TOF): m/z=391.1477, calculated for
C23H22N2O2S (M+H+): 391.1475.
190–1928C; IR (KBr): n=2918, 2360, 1596, 1544, 1448,
1
1379, 1253, 1188, 1175, 1080, 1047, 1009, 848 cmÀ1; H NMR
(400 MHz, CDCl3): d=8.35 (d, J=8 Hz, 1H), 8.27 (d, J=
8 Hz, 2H), 8.20–8.13 (m, 4H), 8.05 (t, J=8 Hz, 1H), 7.89 (d,
J=8 Hz, 1H), 7.84 (d, J=12 Hz, 1H), 7.57–7.50 (m, 3H),
7.09 (d, J=12 Hz, 2H), 6.67 (d, J=8 Hz, 2H), 1.99 (s, 3H);
13C NMR (100 MHz, CDCl3): d=152.0, 145.7, 142.6, 134.8,
133.8, 132.8, 131.2, 131.0, 130.7, 129.4, 129.3, 129.0, 128.4,
127.4, 127.2, 126.4, 126.0, 125.8, 125.7, 125.2, 124.4, 124.3,
124.3, 124.1, 123.6, 120.7, 114.9, 21.3; HR-MS (ESI-TOF):
m/z=473.1335, calculated for C30H20N2O2S (M+H+):
473.1318.
2-Methyl-1-tosyl-1H-benzo[d]imidazole (2ad):[22] Yield:
55%; Rf =0.4 (hexane:ethyl acetate 4:1); white solid; mp
˜
112–1138C (lit.: 1178C); IR (KBr): n=3104, 2920, 2351,
1597, 1546, 1452, 1443, 1425, 1372, 1295, 1274, 1247, 1173,
2-Chloro-6-methoxy-3-(1-tosyl-1H-benzo[d]imidazol-2-yl)-
quinolone (2s): Yield: 93%; Rf =0.4 (hexane:ethyl acetate
1
1188, 1173, 1123, 1089, 1053, 1000 cmÀ1; H NMR (400 MHz,
CDCl3): d=8.02 (d, J=8 Hz, 1H), 7.81 (d, J=12 Hz, 2H),
7.63 (d, J=8 Hz, 1H), 7.37–7.28 (m, 4H), 2.81 (s, 3H), 2.39
(s, 3H); 13C NMR (100 MHz, CDCl3): d=151.5, 146.1, 141.9,
135.5, 133.2, 130.4, 126.9, 124.9, 124.7, 119.7, 113.5, 21.7,
17.0; HR-MS (ESI-TOF): m/z=287.0873, calculated for
C15H14N2O2S (M+H+): 287.0849.
˜
7:3); white solid; mp 171–1738C; IR (KBr): n=2927, 2352,
1615, 1495, 1450, 1380, 1359, 1305, 1254, 1228, 1189, 1176,
1142, 1113, 1088, 1052, 1027 cmÀ1
;
1H NMR (400 MHz,
CDCl3): d=8.19–8.17 (m, 2H), 8.02 (d, J=8 Hz, 1H), 7.83
(d, J=8 Hz, 1H), 7.52–7.43 (m, 5H), 7.19 (d, J=8 Hz, 2H),
7.13 (d, J=4 Hz, 1H), 3.97 (s, 3H), 2.37 (s, 3H); 13C NMR
(100 MHz, CDCl3): d=158.8, 148.2, 146.7, 146.4, 144.2,
142.3, 140.5, 134.9, 133.0, 130.1, 127.4, 127.2, 126.9, 126.2,
125.3, 124.8, 124.3, 121.0, 114.3, 105.6, 55.9, 21.8; HR-MS
(ESI-TOF): m/z=464.0887, calculated for C24H18ClN3O3S
(M+H+): 464.0830.
2-(4-Ethylphenyl)-6-nitro-1-tosyl-1H-benzo[d]imidazole
(2ba): Yield: 33%; Rf =0.6 (hexane:ethyl acetate 4:1); white
˜
solid; mp 139–1418C; IR (KBr): n=2931, 2360, 2090, 1647,
1541, 1522, 1340, 1272, 1178, 1126, 1080, 1010, 834, 668 cmÀ1
;
1H NMR (400 MHz, CDCl3): d=9.12 (s, 1H), 8.31 (d, J=
12 Hz, 1H), 7.79 (d, J=8 Hz, 1H), 7.54 (d, J=8 Hz, 2H),
7.31–7.26 (m, 4H), 7.12 (d, J=8 Hz, 2H), 2.81–2.77 (m,
2H), 2.34 (s, 3H), 1.33 (t, J=6.4 Hz, 3H); 13C NMR
(100 MHz, CDCl3): d=158.9, 148.2, 146.9, 146.6, 145.3,
134.4, 133.6, 131.0, 130.1, 127.5, 127.4, 126.4, 121.0, 120.5,
112.0, 29.0, 21.8, 15.5; HR-MS (ESI-TOF): m/z=422.1162,
calculated for C22H19N3O4S (M+H+): 422.1169.
2-(5-Nitrofuran-2-yl)-1-tosyl-1H-benzo[d]imidazole (2t):
Yield: 93%; Rf =0.5 (hexane:ethyl acetate 4:1); yellow
˜
solid; mp 149–1518C; IR (KBr): n=2914, 2334, 1592, 1541,
1518, 1471, 1382, 1352, 1304, 1277, 1191, 1177, 1130, 1087,
1017 cmÀ1 1H NMR (400 MHz, CDCl3): d=8.16 (d, J=
;
8 Hz, 1H), 8.06 (d, J=8 Hz, 2H), 7.81 (d, J=8 Hz, 1H),
7.54 (d, J=8 Hz, 1H), 7.51–7.46 (m, 2H), 7.44–7.37 (m,
2H), 7.31 (d, J=4 Hz, 1H), 2.42 (s, 3H); 13C NMR
(100 MHz, CDCl3): d=152.7, 146.8, 145.3, 142.1, 140.4,
134.6, 133.5, 130.4, 127.8, 127.1, 125.7, 121.4, 117.1, 114.4,
112.5, 21.8; HR-MS (ESI-TOF): m/z=384.0647, calculated
for C18H13N3O5S (M+H+): 384.0649.
2-(2-Nitrophenyl)-1-tosyl-1H-benzo[d]imidazole-6-carbox-
ylic acid (2bb): Yield: 77%; Rf =0.4 (hexane:ethyl acetate
˜
1:1); white solid; mp 158–1608C; IR (KBr): n=2923, 2364,
1697, 1532, 1384, 1347, 1271, 1176, 1134, 1088 cmÀ1
;
1H NMR (400 MHz, CDCl3): d=8.89 (s, 1H), 8.36 (d, J=
8 Hz, 1H), 8.20 (d, J=8 Hz, 1H), 7.84–7.79 (m, 3H), 7.54
(d, J=12 Hz, 3H), 7.24 (d, J=12 Hz, 2H), 2.39 (s, 3H);
13C NMR (100 MHz, CDCl3): d=170.8, 151.9, 148.3, 146.8,
146.2, 134.5, 133.2, 133.0, 132.7, 131.9, 130.3, 127.6, 127.1,
126.5, 125.9, 124.9, 120.7, 116.6, 21.8; HR-MS (ESI-TOF):
2-Cyclohexyl-1-tosyl-1H-benzo[d]imidazole (2aa): Yield:
73%; Rf =0.5 (hexane:ethyl acetate 4:1); white solid; mp
˜
107–1098C; IR (KBr): n=2927, 2360, 1640, 1539, 1452,
1
1373, 1168, 1121, 1089, 1049, 1004 cmÀ1; H NMR (400 MHz,
CDCl3): d=8.05–8.03 (m, 1H), 7.75 (d, J=8 Hz, 2H), 7.68–
Adv. Synth. Catal. 0000, 000, 0 – 0
ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
asc.wiley-vch.de
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FULL PAPERS
Saikat Maiti and Prasenjit Mal
m/z=438.0759, calculated for C21H15N3O6S (M+H+):
438.0754.
2-(2-Nitrophenyl)-1-tosyl-1H-naphtho[2,3-d]imidazole
(2bc): Yield: 73%; Rf =0.4 (hexane:ethyl acetate 7:3);
134.5, 134.4, 133.4, 130.0, 129.3, 127.6, 126.9, 125.8, 125.6,
120.4, 115.4; HR-MS (ESI-TOF): m/z=341.0419, calculated
for C17H12N2O2S2 (M+H+): 341.0413.
2-(3,4-Dimethoxyphenyl)-1-(phenylsulfonyl)-1H-benzo-
[d]imidazole (2cb): Yield: 87%; Rf =0.4 (hexane:ethyl ace-
˜
yellow solid; mp 89–918C; IR (KBr): n=2923, 2360, 1699,
˜
tate 7:3); white solid; mp 129–1318C; IR (KBr): n=2997,
1592, 1531, 1379, 1348, 1300, 1254, 1175, 1121, 1088, 1066,
1004 cmÀ1 1H NMR (400 MHz, CDCl3): d=8.55 (s, 1H),
;
2835, 2360, 1601, 1585, 1504, 1447, 1379, 1335, 1305, 1271,
1250, 1224, 1187, 1174, 1141, 1121, 1082, 1024 cmÀ1
;
8.35 (d, J=9.2 Hz, 1H), 8.23 (s, 1H), 8.07 (d, J=7.8 Hz,
1H), 8.01 (d, J=8.3 Hz, 1H), 7.83–7.76 (m, 2H), 7.58–7.49
(m, 5H), 7.17 (d, J=8.2 Hz, 2H), 2.34 (s, 3H); 13C NMR
(100 MHz, CDCl3): d=152.0, 148.5, 146.3, 141.8, 134.9,
133.1, 133.0, 132.4, 131.9, 131.7, 131.5, 130.1, 128.5, 128.4,
127.2, 126.3, 125.9, 125.4, 124.8, 118.3, 111.2, 21.8; HR-MS
(ESI-TOF): m/z=444.1005, calulated for C24H17N3O4S1
(M+H+): 444.1013.
1H NMR (400 MHz, CDCl3): d=8.22 (d, J=8 Hz, 1H),
7.72–7.70 (m, 1H), 7.50–7.42 (m, 1H), 7.41–7.39 (m, 4H),
7.32–7.28 (m, 2H), 7.24–7.22 (m, 1H), 7.10 (s, 1H), 6.94 (d,
J=8 Hz, 1H), 3.98 (s, 3H), 3.88 (s, 3H); 13C NMR
(100 MHz, CDCl3): d=154.2, 151.1, 148.1, 142.6, 138.0,
134.4, 134.2, 129.1, 127.0, 125.5, 125.5, 124.5, 122.0, 120.3,
115.4, 113.9, 110.2, 56.1; HR-MS (ESI-TOF): m/z=395.1067,
calculated for C21H18N2O4S (M+H+): 395.1060.
5,6-Dibromo-2-(2-fluorophenyl)-1-tosyl-1H-benzo[d]imi-
dazole (2bd): Yield: 55%; Rf =0.5 (hexane:ethyl acetate
(2-(Benzo[d][1,3]dioxol-5-yl)-1H-benzo[d]imidazol-1-yl)-
(phenyl)methanone (2cc): Yield: 64%; Rf =0.45 (hexa-
ne:ethyl acetate 4:1); white solid; mp 158–1608C; IR (KBr):
˜
4:1); white solid; mp 108–1108C; IR (KBr): n=2918, 2360,
1625, 1595, 1478, 1447, 1427, 1382, 1304, 1259, 1232, 1190,
1178, 1114, 1085, 1031, 1018 cmÀ1
;
1H NMR (400 MHz,
˜
n=2896, 2363, 1699, 1499, 1474, 1450, 1362, 1307, 1237,
1178, 1107, 1038, 932 cmÀ1; H NMR (400 MHz, CDCl3): d=
1
CDCl3): d=8.46 (s, 1H), 8.02 (s, 1H), 7.61–7.55 (m, 1H),
7.43–7.39 (m, 3H), 7.30–7.27 (m, 1H), 7.22–7.16 (m, 3H),
2.38 (s, 3H); 13C NMR (100 MHz, CDCl3): d=161.0 (d,
7.87 (d, J=8 Hz, 1H), 7.72–7.70 (m, 2H), 7.57 (t, J=8 Hz,
1H), 7.41 (s, 1H), 7.39–7.38 (m, 3H), 7.31–7.29 (m, 1H),
7.13–7.09 (m, 2H), 6.71 (d, J=8 Hz, 1H), 5.95 (s, 2H);
13C NMR (100 MHz, CDCl3): d=169.1, 153.5, 149.4, 147.9,
142.0, 134.7, 134.4, 133.0, 130.7, 129.0, 124.8, 124.8, 124.4,
123.6, 119.9, 113.0, 109.4, 108.5, 101.7; HR-MS (ESI-TOF):
m/z=343.1096, calculated for C21H14N2O3 (M+H+):
343.1077.
1JC.F =251 Hz), 149.6, 146.6, 142.8, 134.5, 133.3, 133.2 (d,
4
3JC.F =8.1 Hz), 132.2, 130.2, 127.3, 125.1, 123.8 (d, JC.F
=
2
3.7 Hz), 121.6, 121.0, 119.1, 118.1 (d, JC.F =14.7 Hz), 115.8
(d, 2JC.F =20.8 Hz), 21.8; HR-MS (ESI-TOF): m/z=
522.9091, calculated for C20H13N2O2SBr2F (M+H+):
522.9121.
2-(2-Bromo-5-fluorophenyl)-5,6-dimethyl-1-tosyl-1H-ben-
zo[d]imidazole (2be): Yield: 71%; Rf =0.5 (hexane:ethyl
˜
acetate 4:1); white solid; mp 121–1238C; IR (KBr): n=
2921, 2356, 1596, 1545, 1460, 1380, 1302, 1256, 1188, 1174,
Acknowledgements
1117, 1088, 1040, 1021 cmÀ1 1H NMR (400 MHz, CDCl3):
;
d=7.92 (s, 1H), 7.62–7.58 (m, 1H), 7.56 (s, 1H), 7.54 (d, J=
4 Hz, 2H), 7.22 (d, J=8 Hz, 2H), 7.15–7.06 (m, 2H), 2.46 (s,
3H), 2.38 (s, 6H); 13C NMR (101 MHz, CDCl3): d=160.9
We are thankful to DST, New Delhi, India (Grant nos. INT/
FINLAND/P-06 and SR/S1/IC-59/2010) for financial support
and Dr Sanjib Das (CSIR-IMMT Bhubaneswar) for ICP-
OES analysis. SM is thankful to CSIR (India) for a fellow-
ship.
1
(d, JC,F =247.1 Hz), 148.6, 146.1, 140.6, 135.5, 135.2, 134.4,
3
3
133.9 (d, JC,F =8.2 Hz), 133.8 (d, JC,F =8.7 Hz), 131.2, 130.0,
2
4
127.4, 120.9, 119.8 (d, JC,F =24 Hz), 119.4 (d, JC,F =3.5 Hz),
118.9 (d, 2JC,F =22.1 Hz), 114.3, 21.8, 20.9, 20.2; HR-MS
(ESI-TOF): m/z=473.0329, calculated for C22H18N2O2SBrF
(M+H+): 473.0329.
References
2-(4-Bromophenyl)-5,6-dichloro-1-tosyl-1H-benzo[d]imi-
dazole (2bf): Yield: 56%; Rf =0.7 (hexane:ethyl acetate
[1] a) D. A. Horton, G. T. Bourne, M. L. Smythe, Chem.
Rev. 2003, 103, 893–930; b) J. Valdez, R. Cedillo, A.
Hernꢃndez-Campos, L. Yꢄpez, F. Hernꢃndez-Luis, G.
Navarrete-Vꢃzquez, A. Tapia, R. Cortꢄs, M. Hernꢃn-
dez, R. Castillo, Bioorg. Med. Chem. Lett. 2002, 12,
2221–2224.
˜
4:1); white solid; mp 206–2088C; IR (KBr): n=2971, 2352,
1592, 1432, 1378, 1284, 1234, 1188, 1166, 1083, 1009, 864,
1
756 cmÀ1; H NMR (400 MHz, CDCl3): d=8.33 (s, 1H), 7.79
(s, 1H), 7.62 (d, J=8 Hz, 2H), 7.46 (d, J=8 Hz, 2H), 7.29
(d, J=8 Hz, 2H), 7.15 (d, J=8 Hz, 2H), 2.36 (s, 3H);
13C NMR (100 MHz, CDCl3): d=154.8, 146.6, 141.9, 134.4,
133.1, 132.5, 131.2, 130.1, 130.0, 129.9, 128.2, 127.1, 126.0,
121.6, 116.8, 21.8; HR-MS (ESI-TOF): m/z=494.9301, cal-
culated for C20H13N2O2SBrCl2 (M+H+): 494.9331.
˘
[2] ꢅ. ꢅ. Gꢆven, T. Erdogan, H. Gçker, S. Yıldız, Bioorg.
Med. Chem. Lett. 2007, 17, 2233–2236.
[3] Y.-F. Li, G.-F. Wang, P.-L. He, W.-G. Huang, F.-H. Zhu,
H.-Y. Gao, W. Tang, Y. Luo, C.-L. Feng, L.-P. Shi, Y.-D.
Ren, W. Lu, J.-P. Zuo, J. Med. Chem. 2006, 49, 4790–
4794.
[4] T. de La Fuente, M. Martꢇn-Fontecha, J. Sallander, B.
Benhamffl, M. Campillo, R. O. A. Medina, L. P. Pellissi-
er, S. Claeysen, A. Dumuis, L. Pardo, Ma. L. López-
Rodrꢇguez, J. Med. Chem. 2010, 53, 1357–1369.
[5] M. L. Barreca, A. Rao, L. D. Luca, N. Iraci, A.-M.
Monforte, G. Maga, E. D. Clercq, C. Pannecouque, J.
1-(Phenylsulfonyl)-2-(thiophen-2-yl)-1H-benzo[d]imida-
zole (2ca): Yield: 83%; Rf =0.45 (hexane:ethyl acetate 4:1);
˜
white solid; mp 96–998C; IR (KBr): n=3073, 2364, 1558,
1474, 1448, 1419, 1383, 1337, 1297, 1273, 1233, 1215, 1120,
1
1088, 1061, 1041 cmÀ1; H NMR (400 MHz, CDCl3): d=8.23
(d, J=8 Hz, 1H), 7.81 (d, J=4 Hz, 1H), 7.72 (d, J=8 Hz,
1H), 7.55–7.38 (m, 6H), 7.33–7.27 (m, 2H), 7.21–7.18 (m,
1H); 13C NMR (100 MHz, CDCl3): d=147.8, 142.6, 137.8,
8
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ÝÝ
These are not the final page numbers!

2
À
FULL PAPERS
Phenyliodine Diacetate-Mediated Intramolecular C(sp ) H Amidation
Balzarini, A. Chimirri, Bioorg. Med. Chem. Lett. 2007,
17, 1956–1960.
[6] S. M. Sondhi, S. Rajvanshi, M. Johar, N. Bharti, A.
Azam, A. K. Singh, Eur. J. Med. Chem. 2002, 37, 835–
843.
Y. Du, K. Zhao, Org. Biomol. Chem. 2012, 10, 3606–
3609; c) H. J. Kim, J. Kim, S. H. Cho, S. Chang, J. Am.
Chem. Soc. 2011, 133, 16382–16385; d) R. Samanta,
J. O. Bauer, C. Strohmann, A. P. Antonchick, Org. Lett.
2012, 14, 5518–5521.
[7] Y. Tong, J. J. Bouska, P. A. Ellis, E. F. Johnson, J. Lever-
son, X. Liu, P. A. Marcotte, A. M. Olson, D. J. Oster-
ling, M. Przytulinska, L. E. Rodriguez, Y. Shi, N. Soni,
J. Stavropoulos, S. Thomas, C. K. Donawho, D. J. Frost,
Y. Luo, V. L. Giranda, T. D. Penning, J. Med. Chem.
2009, 52, 6803–6813.
[20] S. Fu, H. Jiang, Y. Deng, W. Zeng, Adv. Synth. Catal.
2011, 353, 2795–2804.
[21] M. Shen, T. G. Driver, Org. Lett. 2008, 10, 3367–3370.
[22] S. K. Alla, R. K. Kumar, P. Sadhu, T. Punniyamurthy,
Org. Lett. 2013, 15, 1334–1337.
[23] D. N. Kommi, D. Kumar, R. Bansal, R. Chebolu, A. K.
Chakraborti, Green Chem. 2012, 14, 3329–3335.
[24] a) D. N. Rao, S. Rasheed, R. A. Vishwakarma, P. Das,
RSC Adv. 2014, 4, 25600–25604; b) G.-Q. Liu, Y.-M. Li,
J. Org. Chem. 2014, 79, 10094–10109; c) G. Jacquemot,
S. Canesi, J. Org. Chem. 2012, 77, 7588–7594; d) S.
Manna, K. Matcha, A. P. Antonchick, Angew. Chem.
2014, 126, 8302–8395; Angew. Chem. Int. Ed. 2014, 53,
8163–8166; e) K. Morimoto, K. Sakamoto, Y. Ohnishi,
T. Miyamoto, M. Ito, T. Dohi, Y. Kita, Chem. Eur. J.
2013, 19, 8726–8731; f) S. Okumura, Y. Takeda, K.
Kiyokawa, S. Minakata, Chem. Commun. 2013, 49,
9266–9268.
[25] a) F. Collet, C. Lescot, P. Dauban, Chem. Soc. Rev.
2011, 40, 1926–1936; b) F. Collet, R. H. Dodd, P.
Dauban, Chem. Commun. 2009, 5061–5074.
[26] a) V. V. Zhdankin, P. J. Stang, Chem. Rev. 2002, 102,
2523–2584; b) V. V. Zhdankin, P. J. Stang, Chem. Rev.
2008, 108, 5299–5358; c) T. Wirth, Angew. Chem. 2005,
117, 3722–3731; Angew. Chem. Int. Ed. 2005, 44, 3656–
3665; d) T. Dohi, Y. Kita, Chem. Commun. 2009, 2073–
2085; e) C.-L. Sun, Z.-J. Shi, Chem. Rev. 2014, 114,
9219–9280; f) M. Brown, U. Farid, T. Wirth, Synlett
2013, 24, 424–431; g) R. Samanta, K. Matcha, A. P. An-
tonchick, Eur. J. Org. Chem. 2013, 2013, 5769–5804.
[27] T. K. Achar, S. Maiti, P. Mal, RSC Adv. 2014, 4, 12834–
12839.
[8] W. A. Denny, G. W. Rewcastle, B. C. Baguley, J. Med.
Chem. 1990, 33, 814–819.
[9] L. C. R. Carvalho, E. Fernandes, M. M. B. Marques,
Chem. Eur. J. 2011, 17, 12544–12555.
[10] a) T. Hille, T. Irrgang, R. Kempe, Chem. Eur. J. 2014,
20, 5569–5572; b) Y. Kim, M. R. Kumar, N. Park, Y.
Heo, S. Lee, J. Org. Chem. 2011, 76, 9577–9583; c) N. T.
Jui, S. L. Buchwald, Angew. Chem. 2013, 125, 11838–
11841; Angew. Chem. Int. Ed. 2013, 52, 11624–11627;
d) J.-P. Lin, F.-H. Zhang, Y.-Q. Long, Org. Lett. 2014,
16, 2822–2825; e) C. Sambiagio, S. P. Marsden, A. J.
Blacker, P. C. McGowan, Chem. Soc. Rev. 2014, 43,
3525–3550; f) T. R. M. Rauws, B. U. W. Maes, Chem.
Soc. Rev. 2012, 41, 2463–2497; g) G. Naresh, R. Kant, T.
Narender, J. Org. Chem. 2014, 79, 3821–3829; h) R.
Sunke, P. V. Babu, S. Yellanki, R. Medishetti, P. Kulkar-
ni, M. Pal, Org. Biomol. Chem. 2014, 12, 6800–6805;
i) R. K. Kumar, T. Punniyamurthy, RSC Adv. 2012, 2,
4616–4619.
[11] a) H. Jin, X. Xu, J. Gao, J. Zhong, Y. Wang, Adv.
Synth. Catal. 2010, 352, 347–350; b) T. Ramana, T. Pun-
niyamurthy, Chem. Eur. J. 2012, 18, 13279–13283.
[12] R. Chebolu, D. N. Kommi, D. Kumar, N. Bollineni,
A. K. Chakraborti, J. Org. Chem. 2012, 77, 10158–
10167.
[13] M. Pizzetti, E. De Luca, E. Petricci, A. Porcheddu, M.
Taddei, Adv. Synth. Catal. 2012, 354, 2453–2464.
[14] H. Li, D. Mꢆller, L. Guꢄnꢄe, A. Alexakis, Org. Lett.
2012, 14, 5880–5883.
[28] I. Tellitu, S. Serna, M. T. Herrero, I. Moreno, E. Domꢇ-
nguez, R. SanMartin, J. Org. Chem. 2007, 72, 1526–
1529.
[15] L. Hao, Y. Zhao, B. Yu, H. Zhang, H. Xu, Z. Liu,
Green Chem. 2014, 16, 3039–3044.
[16] S. Samanta, S. Das, P. Biswas, J. Org. Chem. 2013, 78,
11184–11193.
[17] M. S. Mayo, X. Yu, X. Zhou, X. Feng, Y. Yamamoto,
M. Bao, Org. Lett. 2014, 16, 764–767.
[29] H. M. Lovick, F. E. Michael, J. Am. Chem. Soc. 2010,
132, 1249–1251.
[30] I. Tellitu, A. Urrejola, S. Serna, I. Moreno, M. T. Her-
rero, E. Domꢇnguez, R. SanMartin, A. Correa, Eur. J.
Org. Chem. 2007, 2007, 437–444.
[18] a) J.-H. Chu, W.-T. Hsu, Y.-H. Wu, M.-F. Chiang, N.-H.
Hsu, H.-P. Huang, M.-J. Wu, J. Org. Chem. 2014, 79,
11395–11408; b) K. B. Hong, J. N. Johnston, Org. Lett.
2014, 16, 3804–3807; c) S. Suzuki, T. Kamo, K. Fukushi,
T. Hiramatsu, E. Tokunaga, T. Dohi, Y. Kita, N. Shiba-
ta, Chem. Sci. 2014, 5, 2754–2760; d) L. Fra, A. Millꢃn,
J. A. Souto, K. MuÇiz, Angew. Chem. 2014, 126, 7477–
7481; Angew. Chem. Int. Ed. 2014, 53, 7349–7353; e) G.
Qian, B. Liu, Q. Tan, S. Zhang, B. Xu, Eur. J. Org.
Chem. 2014, 4837–4843.
[31] T. Kitamura, M. D. Hossain, Synthesis 2005, 2005,
1932–1934.
[32] H. Togo, M. Iinuma, K. Moriyama, Synlett 2012, 23,
2663–2666.
[33] A. McKillop, D. Kemp, Tetrahedron 1989, 45, 3299–
3306.
[34] K. R. Reddy, G. G. Krishna, Tetrahedron Lett. 2005, 46,
661–663.
[35] Z. Peng, J. W. Wong, E. C. Hansen, A. L. A. Puchlo-
pek-Dermenci, H. J. Clarke, Org. Lett. 2014, 16, 860–
863.
[19] a) M.-L. Louillat, F. W. Patureau, Chem. Soc. Rev.
2014, 43, 901–910; b) X. Ban, Y. Pan, Y. Lin, S. Wang,
Adv. Synth. Catal. 0000, 000, 0 – 0
ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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FULL PAPERS
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À
10 Phenyliodine Diacetate-Mediated Intramolecular C(sp ) H
Amidation for 1,2-Disubstituted Benzimidazole Synthesis
under Metal-Free Conditions
Adv. Synth. Catal. 2015, 357, 1 – 10
Saikat Maiti, Prasenjit Mal*
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