Pd-catalysed ortho-C-H acylation/cross coupling of 2-arylbenzo[d]thiazoles with aldehydes using tert-butyl hydroperoxide as oxidant

Article abstract of DOI:10.3184/174751913X13639769724276

An efficient palladium-catalysed protocol for direct C-H bond acylation by cross coupling of 2-arylbenzo[d]thiazoles and aldehydes using tert-butyl hydroperoxide as the oxidant is reported. The process provides a useful method for the synthesis of aromatic ketones directly from aldehydes. In addition, the reaction can tolerate various functional groups in good yield with high regioselectivity.

Full text of DOI:10.3184/174751913X13639769724276

JOURNAL OF CHEMICAL RESEARCH 2013
RESEARCH PAPER 263
MAY, 263–267
Pd-catalysed ortho-C-H acylation/cross coupling of
2-arylbenzo[d]thiazoles with aldehydes using tert-butyl
hydroperoxide as oxidant
Jian Wang, Ziyi Nie, Yan Li, Shuang Tan, Jiantao Jiang, Pusheng Jiang and Qiuping Ding*
Key Laboratory of Functional Small Organic Molecules, Ministry of Education and College of Chemistry & Chemical Engineering, Jiangxi
Normal University, Nanchang, Jiangxi 330022, P. R. China
An efficient palladium-catalysed protocol for direct C–H bond acylation by cross coupling of 2-arylbenzo[d]thiazoles
and aldehydes using tert-butyl hydroperoxide as the oxidant is reported. The process provides a useful method for
the synthesis of aromatic ketones directly from aldehydes. In addition, the reaction can tolerate various functional
groups in good yield with high regioselectivity.
Keywords: 2-arylbenzo[d]thiazole, C–H activation, acylation, cross-coupling
Diaryl and aryl alkyl ketones are important building blocks in
the synthesis of natural products, pharmaceutical, functional
materials and agrochemicals.1–5 Friedel–Crafts acylation reac-
tions are usually their classical method of synthesis.6–8 The
narrow scope of substrate, poor functional group compatibil-
ity, the requirement of a stoichiometric amount of Lewis acid
and the untunable regioselectivity limit their applications.
Thus it is highly desirable to develop efficient methods for
access to elaborated ketones.
in other solvents. Subsequently, various Pd(II) salts or Pd(0)
complexes were tested for this direct acylation in the presence
of TBHP in AcOH. Poor yields were observed when other
Pd(II) salts (such as PdCl2, Pd(PPh3)2Cl2, Pd(CH3CN)2Cl2,
Pd(PhCN)2Cl2) were used as catalysts; only Pd(dba)2 (62%)
exhibited significant activity (Table 1, entries 11–15). The
desired product was obtained in 23% yield when oxygen was
used as the sole oxidant (Table 1, entry 16). However, the use
of other oxidants, such as oxone, benzoquinone (BQ) and
K2S2O8, were relatively ineffective for the direct acylation
reaction (Table 1, entries 17–19). Further optimisation
demonstrated that the yields could be reduced when the amount
of 2a was cut down (Table 1, entries 20 and 21). However,
when the amount of TBHP was reduced to 2.0 equiv, the
coupling yield (74%) could be further improved (Table 1,
entry 22).
Recently, much progress has been made in transition-
metal-catalysed direct conversion of aromatic C–H bonds into
carbon–carbon and carbon–heteroatom bonds.9–15 The transi-
tion-metal-catalysed ortho C–H acylation of arenes with
aldehydes represents another direct and promising approach to
the access to ketones.16–25 For example, in 2009, Cheng and
co-workers16 pioneered the development of Pd-catalysed direct
ortho-C–H acylation of 2-arylpyridines with aldehydes to give
aromatic ketones using air as the terminal oxidant. In 2010, Li
and co-workers17 reported the same acylation reaction using
tert-butyl hydroperoxide (TBHP) as the oxidant. In 2010, Yu
and co-workers18 developed the direct C–H bond acylation by
cross coupling aromatic oximes and aldehydes in the presence
of TBHP. In 2010, the groups of Yu,19 Wang,20 and Kwong21
also developed the Pd-catalysed direct ortho-C–H bond activa-
tion of anilides by oxidative cross-coupling with aldehydes
using TBHP as oxidant. During the course of our investigation,
Wu and co-workers developed an efficient Pd-catalysed protocol
for benzoxazole-directed ortho-acylation with aldehydes using
TBHP as oxidant and PPh3 as ligand in chlorobenzene.22 In
addition,therearealsosomereportsusingtoluenederivatives26,27
as useful carbonyl sources in the presence of a transition-metal
catalyst and oxidant. Inspired by the recent studies of direct
ortho-C–H bond activation of arenes and our interests in C–H
functionalisation of 2-arylbenzothiazoles,28,29 we have explored
the possibility of ortho-acylation of 2-aryl-benzo[d]thiazoles
with aldehydes through direct C–H bond activation. We have
achieved this transformation.We now describe the Pd-catalysed
ortho-acylation of 2-aryl-benzo[d]thiazoles with aldehydes
using TBHP as oxidant under ligand-free conditions.
Under the optimised reaction conditions [Pd(OAc)2 (5 mol%),
ratio of 1/2 = 1/3, TBHP (2.0 equiv.), 120 °C], the reactivity of
different 2-arylbenzo[d]thiazoles was investigated (Table 2).
Table 1 Optimisation of the reaction conditionsa
Entry
[Pd]
Oxidant
Solvent
Yield/%b
1
2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
PdCl2
Pd(PPh)3Cl2
Pd(CH3CN)2Cl2
Pd(PhCN)2Cl2
Pd(dba)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
TBHP
TBHP
TBHP
TBHP
TBHP
TBHP
TBHP
TBHP
TBHP
TBHP
TBHP
TBHP
TBHP
TBHP
TBHP
O2
Toluene
Xylene
Dioxane
DMAc
AcOH
DMF
65
46
Trace
Trace
70
3
4
5
6
Trace
67
7
PhCl
8
HCOOH
Ac2O
TfOH
16
9
30
10
11
12
13
14
15
16
17
18
19
20c
21d
22e
–
AcOH
AcOH
AcOH
AcOH
AcOH
AcOH
AcOH
AcOH
AcOH
AcOH
AcOH
AcOH
16
16
10
Based on previous work, we began by examining the reaction
of2-(o-tolyl)benzo[d]thiazole(1a,0.2mmol)andbenzaldehyde
(2a, 0.6 mmol) using TBHP (0.6 mmol) as oxidant, in the
presence of Pd(OAc)2 (5 mmol%) in toluene (2 mL) at 120 °C
for 2 h. The expected acylated product was obtained in 65%
yield. We also tested other solvents, such as xylene, dioxane,
AcOH, DMF, and PhCl (Table 1, entries 2–10). The results
revealed that AcOH (70% yield) and PhCl (67% yield) were
the suitable solvents, and only inferior results were observed
18
62
23
Oxone
BQ
K2S2O8
TBHP
TBHP
TBHP
–
Trace
–
60
55
74
aConditions: 1a (0.2 mmol), 2a (0.6 mmol), [Pd] catalyst (5 mol
%), oxidant (3.0 equiv.), 120 °C, 2 h. b Isolated yield. c 2.5 equiv.
of 2a were used. d 2.0 equiv. of 2a were used. e 2.0 equiv. of
TBHP were used.
* Correspondent. E-mail: dingqiuping@jxnu.edu.cn

264 JOURNAL OF CHEMICAL RESEARCH 2013
The coupling of 2-arylbenzo[d]thiazoles 1b–i with electron-
withdrawing groups (Cl, F) at the ortho-position of the 2-
phenyl ring smoothly underwent the acylation reaction to
afford the corresponding products 3b–i in good yields. For
example, the reaction of 2-(2-chlorophenyl)benzo[d]thiazole
1b under the standard conditions gave 3b in 87% yield. A
relatively lower yield was obtained when 2-(2-fluorophenyl)
benzo[d]thiazole 1f was used, and the desired product 3f was
achieved in 67% yield. However, a moderate electron-donating
group (CH3) at the ortho-position of 2-arylbenzo[d]thiazoles
gave a lower yield of oxidative cross-coupling product 3j.
6-Chloro-2-(o-tolyl)benzo[d]thiazole 1l and 6-fluoro-2-(o-
tolyl)benzo[d]thiazole 1m (with electron-withdrawing group
ClandF,respectively,onthephenylringofthebenzo[d]thiazole)
were found to be good substrates for this transformation,
affording the corresponding products 3l and 3m in good yields.
Then, the regioselective ortho acylation of meta-substituted
2-arylbenzo[d]thiazoles was also investigated. The acylation
reaction of 2-arylbenzo[d]thiazoles 1n–q occurred exclusively
at the less sterically hindered position, and gave moderate to
good yields with high regioselectivity.
To examine the substrate scope and limitations, a broad
range of aldehydes was screened in coupling with 6-chloro-2-
(2-chlorophenyl)benzo[d]thiazole 1d under optimal reaction
conditions (Table 3). In general, electron-donating (Me, OMe)
and -withdrawing (F, Cl, Br and CN) groups are tolerated. In
contrast, electron-rich aldehydes were less reactive under the
standard reaction conditions. The reaction yield decreased
dramatically when the aliphatic aldehyde butyraldehyde 2h
was used as the substrate, and only a 19% yield of product 3y
was achieved.
2-arylbenzo[d]thiazole with aldehyde through direct C−H
bond activation is suggested in Scheme 1. First, Pd-catalysed
sp2 C−H bond activation of 2-arylbenzo[d]thiazole occurs to
form a five-membered palladacycle intermediate A. Second,
the palladacycle A reacted with the acyl radical which was
produced from aldehyde in the presence of TBHP to form
either a reactive PdIII or PdIV intermediate B. Finally, interme-
diate B underwent reductive elimination to form the coupling
product 3 and regenerate PdII for the next catalytic cycle.
In summary, an efficient approach for the direct acylation of
the aromatic sp2 C–H bond has been developed. The process
provided a very useful method for the synthesis of aromatic
ketones directly from aldehydes. In addition, the reaction can
tolerate various functional groups in good yields with high
regioselectivity.
Experimental
C–H bond activation/acylation of 2-arylbenzothiazoles 1 with
aldehydes 2; general procedure
In a 20-mL reaction tube, a mixture of 2-arylbenzothiazole 1
(0.3 mmol, 1.0 equiv.), aldehyde 2 (0.9 mmol, 3.0 equiv.), TBHP
(2.0 equiv, 65% aqueous) and Pd(OAc)2 (3.5 mg, 5 mol %) in AcOH
(2.0 mL) was stirred at 120 °C for 2 h. After completion of the
reaction, as indicated by TLC, the mixture was cooled to room tem-
perature, the resulting mixture was extracted with ethyl acetate (3 ×
20 mL). The organic layer was evaporated under vacuum, and then the
residue was purified by flash column chromatography on silica gel to
provide the corresponding pure coupling product 3.
(2-(Benzo[d]thiazol-2-yl)-3-methylphenyl)(phenyl)methanone
(3a): Yellow solid;74% yield, m.p. 135–136 °C; 1H NMR (400 MHz,
CDCl3) δ 2.43 (s, 3H), 7.27 (t, J = 7.6 Hz, 2H), 7.33 (d, J = 8.0 Hz,
1H), 7.37–7.42 (m, 3H), 7.46–7.48 (m, 2H), 7.69 (d, J = 7.6 Hz, 2H),
7.78 (d, J = 7.6 Hz, 1H), 7.93 (d, J = 8.0 Hz, 1H); 13C NMR (100 MHz,
CDCl3) δ 20.5, 121.3, 123.4, 125.2, 126.0, 126.6, 128.0, 129.3, 129.9,
Based on the previous reports, the proposed reaction
pathway of the palladium-catalysed ortho-acylation of
Table 2 Reaction of benzaldehyde with 2-arylbenzo[d]thiazolea
a Reaction conditions: 1 (0.3 mmol), 2a (0.9 mmol), Pd(OAc)2 (5 mol%), TBHP (2 equiv.), 120 °C, 2 h in air. b Isolated yields based on 1.

JOURNAL OF CHEMICAL RESEARCH 2013 265
Table 3 Scope of aldehydesa
a Reaction conditions: 1d (0.3 mmol), 2 (0.9 mmol), Pd(OAc)2 (5 mol%), TBHP (2 equiv.), 120 °C, 2 h in air. b Isolated yields based on
1d.
J = 8.4 Hz, 1H); 13C NMR (100 MHz, CDCl3) δ 21.6, 120.9, 123.0,
127.4, 127.7, 128.1, 129.4, 130.5, 131.8, 131.9, 132.8, 134.1, 135.8,
136.5, 137.0, 142.9, 150.4, 160.9, 195.8; IR (KBr) ν/cm−1: 2922, 1670,
1276, 707; HRMS (ESI): m/z [M + H]+ calcd for C21H15ClNOS:
364.0563, found: 363.0568.
(3-Chloro-2-(6-chlorobenzo[d]thiazol-2-yl)phenyl)(phenyl)methan-
one (3d): Yellow solid; 87% yield; m.p. 147–148 °C; 1H NMR
(400 MHz, CDCl3) δ 7.26 (t, J = 7.6 Hz, 2H), 7.34 (d, J = 8.8 Hz, 1H),
7.38 (t, J = 7.6 Hz, 1H), 7.49 (d, J = 7.6 Hz, 1H), 7.54 (t, J = 7.6 Hz,
1H), 7.64 (d, J = 7.6 Hz, 2H), 7.69 (d, J = 7.6 Hz, 1H), 7.76 (t, J =
4.0 Hz, 2H); 13C NMR (100 MHz, CDCl3) δ 120.9, 124.3, 127.0,
127.6, 128.2, 129.4, 130.9, 131.3, 131.6, 132.1, 133.0, 134.1, 136.9,
137.5, 142.9, 150.7, 162.7, 195.6; IR (KBr) ν/cm−1: 1672, 1303, 826;
HRMS (ESI): m/z [M + H]+ calcd for C20H12Cl2NOS: 384.0017, found:
384.0021.
(3-Chloro-2-(6-fluorobenzo[d]thiazol-2-yl)phenyl)(phenyl)methan-
one (3e): Yellow solid; 79% yield; m.p. 152–153 °C; 1H NMR
(400 MHz, CDCl3) δ 7.13 (t, J = 8.8 Hz, 1H), 7.26 (t, J = 7.6 Hz, 2H),
7.38 (t, J = 7.2 Hz, 1H), 7.46–7.51 (m, 2H), 7.54 (d, J = 8.0 Hz, 1H),
7.64 (d, J = 7.6 Hz, 2H), 7.69 (d, J = 7.6 Hz, 1H), 7.81 (dd, J = 4.8,
8.8 Hz, 1H); 13C NMR (100 MHz, CDCl3) δ 107.4 (d, 2JC-F = 27.0 Hz),
114.9 (d, JC-F = 25.0 Hz), 124.6 (d, JC-F = 10.0 Hz), 127.6, 128.2,
129.4, 130.8, 131.4, 132.0, 132.9, 134.1, 136.9, 137.3 (d, 3JC-F = 11.0
Hz), 142.9, 148.8, 160.6 (d, 1JC-F = 245.0 Hz), 195.7; IR (KBr) ν/cm−1:
1667, 1321, 750; HRMS (ESI): m/z [M + H]+ calcd for C20H12ClFNOS:
368.0312, found: 368.0310.
2
3
Scheme 1 Proposed mechanism for the Pd-catalysed
ortho-acylation reaction.
132.5, 132.7, 132.8, 136.2, 137.4, 138.2, 140.7, 152.9, 165.2, 197.3;
IR (KBr) ν/cm−1: 2923, 1735, 1458, 1087, 775; HRMS (ESI): m/z
[M + H]+ calcd for C21H16NOS: 330.0953; found: 330.0950.
(2-(Benzo[d]thiazol-2-yl)-3-fluorophenyl)(phenyl)methanone (3f):
Yellow solid; 67% yield; m.p. 108–109 °C; 1H NMR (400 MHz,
CDCl3) δ 7.25–7.40 (m, 8H), 7.53–7.59 (m, 1H), 7.73 (d, J = 8.4 Hz,
2H), 7.87 (dd, J = 4.0, 8.4 Hz, 1H); 13C NMR (100 MHz, CDCl3)
δ 117.6 (d, 2JC-F = 23.0 Hz), 120.4 (d, 3JC-F = 13.0 Hz), 121.3, 123.4,
(2-(Benzo[d]thiazol-2-yl)-3-chlorophenyl)(phenyl)methanone(3b):
Yellow solid; 87% yield; m.p. 178–179 °C; 1H NMR (400 MHz,
CDCl3) δ 7.26 (t, J = 7.6 Hz, 2H), 7.31–7.41 (m, 3H), 7.49–7.56 (m,
2H), 7.65 (d, J = 7.6 Hz, 2H), 7.69 (d, J = 7.6 Hz, 1H), 7.80 (d, J =
7.6 Hz, 1H), 7.88 (d, J = 8.0 Hz, 1H); 13C NMR (100 MHz, CDCl3)
δ 121.3, 123.6, 125.6, 126.1, 127.5, 128.1, 129.4, 130.6, 131.8, 132.0,
132.9, 134.2, 136.3, 137.0, 142.9, 152.2, 162.1, 195.8; IR (KBr)
ν/cm−1: 1669, 1317, 758; HRMS (ESI): m/z [M + H]+ calcd for
C20H13ClNOS: 350.0406, found: 350.0400.
(3-Chloro-2-(6-methylbenzo[d]thiazol-2-yl)phenyl)(phenyl)methan-
one (3c): Yellow solid; 81% yield; m.p. 134–135 °C; 1H NMR
(400 MHz, CDCl3) δ 2.43 (s, 3H), 7.19 (d, J = 8.4 Hz, 1H), 7.25 (t,
J = 7.2 Hz, 2H), 7.36 (t, J = 7.2 Hz, 1H), 7.47–7.52 (m, 2H), 7.57
(s, 1H), 7.64 (d, J = 7.6 Hz, 2H), 7.68 (d, J = 7.6 Hz, 1H), 7.74 (d,
3
124.7, 125.5, 126.1, 128.2, 129.0, 131.7 (d, JC-F = 9.0 Hz), 132.6,
135.8, 137.6, 142.4, 152.0, 158.3, 160.1 (d, 1JC-F = 252.0 Hz), 196.0;
IR (KBr) ν/cm−1: 1668, 1299, 1273, 757; HRMS (ESI): m/z [M + H]+
calcd for C20H13FNOS: 334.0702, found: 334.0700.
(3-Fluoro-2-(6-methylbenzo[d]thiazol-2-yl)phenyl)(phenyl)methan-
one (3g): Yellow solid; 72% yield; m.p. 131–132 °C; 1H NMR
(400 MHz, CDCl3) δ 2.41 (s, 3H), 7.15 (d, J = 8.4 Hz, 1H), 7.26 (t,
J = 7.6 Hz, 2H), 7.34 (d, J = 6.8 Hz, 2H), 7.37 (t, J = 9.2 Hz, 1H),
7.55 (t, J = 7.6 Hz, 1H), 7.57 (s, 1H), 7.63 (d, J = 8.0 Hz, 1H), 7.71 (d,
J = 7.6 Hz, 2H); 13C NMR (100 MHz, CDCl3) δ 21.6, 117.6 (d, 2JC-F
=
22.0 Hz), 120.5 (d, 2JC-F = 14.0 Hz), 120.9, 122.9, 124.7, 127.8, 128.2,

266 JOURNAL OF CHEMICAL RESEARCH 2013
3
2
3
128.9, 131.5 (d, JC-F = 9.0 Hz), 132.6, 135.8, 136.0, 137.6, 142.3,
(d, JC-F = 24.0 Hz), 124.3 (d, JC-F = 10.0 Hz), 128.2, 129.2, 129.3,
150.2, 157.1, 160.0 (d, JC-F = 253.0 Hz), 196.1; IR (KBr) ν/cm−1:
1
3
130.2, 131.0, 132.0, 132.6, 136.3 (d, JC-F = 12.0 Hz), 136.9, 137.9,
2923, 1671, 1299, 745; HRMS (ESI): m/z [M + H]+ calcd for
C21H15FNOS: 348.0858, found: 348.0859.
1
140.7, 150.1, 160.5 (d, JC-F = 244.0 Hz), 165.4, 197.6; IR (KBr)
ν/cm−1: 2926, 1663, 1280, 929, 733; HRMS (ESI): m/z [M + H]+ calcd
for C21H15FNOS: 348.0858, found: 348.0861.
(2-(6-Chlorobenzo[d]thiazol-2-yl)-3-fluorophenyl)(phenyl)methan-
one (3h): Yellow solid; 68% yield; m.p. 170–171 °C; 1H NMR
(400 MHz, CDCl3) δ 7.27–7.42 (m, 6H), 7.57–7.62 (m, 1H), 7.65 (d,
J = 8.8 Hz, 1H), 7.71 (d, J = 7.6 Hz, 2H), 7.78 (s, 1H); 13C NMR
(2-(Benzo[d]thiazol-2-yl)-4-chlorophenyl)(phenyl)methanone(3p):
White solid (72% yield; m.p. 134–135 °C; 1H NMR (400 MHz,
CDCl3) δ 7.25–7.34 (m, 3H), 7.35–7.41 (m, 2H), 7.48 (d, J = 8.4 Hz,
1H), 7.57 (d, J = 8.0 Hz, 1H), 7.74 (d, J = 7.6 Hz, 2H), 7.79 (t, J =
6.8 Hz, 2H), 7.93 (s, 1H); 13C NMR (100 MHz, CDCl3) δ 121.5, 123.6,
125.7, 126.4, 128.3, 129.2, 129.5, 130.2, 130.3, 132.9, 133.9, 135.4,
136.2, 137.5, 138.0, 153.3, 163.7, 196.5; IR (KBr) ν/cm−1: 2960, 1665,
1277, 778; HRMS (ESI): m/z [M + H]+ calcd for C20H13ClNOS:
350.0406, found: 350.0411.
(4-Chloro-2-(6-methylbenzo[d]thiazol-2-yl)phenyl)(phenyl)methan-
one (3q): Yellow solid; 67% yield; m.p. 87–88 °C 1H NMR
(400 MHz, CDCl3) δ 2.41 (s, 3H), 7.17 (d, J = 8.4 Hz, 1H), 7.28 (t,
J = 7.2 Hz, 2H), 7.38 (t, J = 7.2 Hz, 1H), 7.47 (d, J = 8.0 Hz, 1H),
7.55 (d, J = 7.6 Hz, 1H), 7.56 (s, 1H), 7.66 (d, J = 8.4 Hz, 1H), 7.73
(d, J = 7.6 Hz, 2H), 7.90 (s, 1H); 13C NMR (100 MHz, CDCl3) δ 21.6,
121.2, 123.1, 128.0, 128.3, 129.2, 129.3, 130.1, 130.3, 132.9, 134.0,
135.6, 136.0, 136.2, 137.5, 137.9, 151.5, 162.5, 196.6; IR (KBr)
ν/cm−1: 2961, 1666, 1273, 738; HRMS (ESI): m/z [M + H]+ calcd for
C21H15ClNOS: 364.0563, found: 364.0559.
(2-(Benzo[d]thiazol-2-yl)-4-methylphenyl)(phenyl)methanone(3r):
Yellow solid; 76% yield; m.p. 109–110 °C; 1H NMR (400 MHz,
CDCl3) δ 7.29 (t, J = 7.6 Hz, 3H), 7.34–7.38 (m, 2H), 7.54 (d, J =
6.8 Hz, 1H), 7.60–7.64 (m, 2H), 7.77 (t, J = 7.6 Hz, 4H), 7.93 (d, J =
7.2 Hz, 1H); 13C NMR (100 MHz, CDCl3) δ 121.4, 123.4, 125.3,
126.2, 128.2, 128.9, 129.3, 129.6, 130.2, 130.3, 132.1, 132.7, 135.3,
137.8, 139.7, 153.5, 165.3, 197.7; IR (KBr) ν/cm−1: 2924, 1666, 1256,
799; HRMS (ESI): m/z [M + H]+ calcd for C20H14NOS: 316.0796,
found: 316.0791.
(3-Chloro-2-(6-chlorobenzo[d]thiazol-2-yl)phenyl)(p-tolyl)-
methanone (3s): Yellow solid; 60% yield; m.p. 115–116 °C; 1H NMR
(400 MHz, CDCl3) δ 2.31 (s, 3H), 7.10 (d, J = 8.0 Hz, 2H), 7.35 (d,
J = 8.8 Hz, 1H), 7.46 (d, J = 7.2 Hz, 1H), 7.52 (d, J = 8.0 Hz, 1H), 7.57
(d, J = 8.0 Hz, 2H), 7.68 (d, J = 8.0 Hz, 1H), 7.77 (s, 1H), 7.79 (d,
J = 6.8 Hz, 1H); 13C NMR (100 MHz, CDCl3) δ 21.7, 120.9, 124.4,
126.9, 127.4, 129.0 129.8, 130.7, 131.3, 131.5, 131.8, 134.2, 134.3,
137.5, 143.1, 144.1, 150.8, 162.8, 195.2; IR (KBr) ν/cm−1: 2922, 1664,
1276, 752; HRMS (ESI): m/z [M + H]+ calcd for C21H14Cl2NOS:
398.0173, found: 398.0168.
(3-Chloro-2-(6-chlorobenzo[d]thiazol-2-yl)phenyl)(4-methoxy-
phenyl)methanone (3t): Yellow oil; 55% yield;; 1H NMR (400 MHz,
CDCl3) δ 3.79 (s, 3H), 6.79 (d, J = 8.8 Hz, 2H), 7.35 (d, J = 8.4Hz,
1H), 7.44 (d, J = 7.2 Hz, 1H), 7.52 (t, J = 8.0 Hz, 1H), 7.67 (d, J =
8.0 Hz, 3H), 7.79 (s, 1H), 7.80 (d, J = 8.0 Hz, 1H); 13C NMR
(100 MHz, CDCl3) δ 55.5, 113.6, 120.9, 124.3, 126.9, 127.1, 129.7,
130.7, 131.1, 131.5, 131.6, 132.1, 134.3, 137.5, 143.1, 150.9, 162.9,
163.6, 194.1; IR (KBr) ν/cm−1: 2938, 1659, 1256, 765; HRMS (ESI):
m/z [M + H]+ calcd for C21H14Cl2NO2S: 414.0122, found: 414.0116.
(3-Chloro-2-(6-chlorobenzo[d]thiazol-2-yl)phenyl)(4-fluoro-
phenyl)methanone (3u): White solid; 83% yield; m.p. 116–117 °C;
1H NMR (400 MHz, CDCl3) δ 6.95 (t, J = 8.4 Hz, 2H), 7.36 (d,
J = 8.8 Hz, 1H), 7.47 (d, J = 7.6 Hz, 1H), 7.55 (t, J = 7.6 Hz, 1H),
7.65–7.71 (m, 3H), 7.76 (t, J = 8.8 Hz, 1H), 7.79 (s, 1H); 13C NMR
(100 MHz, CDCl3) δ 115.5 (d, 2JC-F = 22.0 Hz), 120.9, 124.2, 127.2 (d,
2JC-F = 24.0 Hz), 130.9, 131.1, 131.7, 131.9 (d, 3JC-F = 10.0 Hz), 132.1,
133.4, 134.1, 137.4, 142.6, 150.6, 162.5, 165.5 (d, 1JC-F = 254.0 Hz),
194.1; IR (KBr) ν/cm−1: 3064, 1670, 1597, 756; HRMS (ESI): m/z
[M + H]+ calcd for C20H11Cl2FNO2S: 401.9922, found: 401.9916.
(3-Chloro-2-(6-chlorobenzo[d]thiazol-2-yl)phenyl)(4-chloro-
phenyl)methanone (3v): Yellow solid; 72% yield; m.p. 136–137 °C
1H NMR (400 MHz, CDCl3) δ 7.25 (d, J = 8.4 Hz, 2H), 7.36 (d,
J = 8.4 Hz, 1H), 7.46 (d, J = 7.6 Hz, 1H), 7.55 (t, J = 8.0 Hz, 1H), 7.59
(d, J = 8.4 Hz, 2H), 7.70 (d, J = 8.0 Hz, 1H), 7.76 (d, J = 8.8 Hz, 1H),
7.80 (s, 1H); 13C NMR (100 MHz, CDCl3) δ 121.0, 124.2, 127.1,
127.4, 128.6, 130.7, 130.9, 131.2, 131.8, 132.2, 134.1, 135.3, 137.4,
139.4, 142.5, 150.6, 162.4, 194.4; IR (KBr) ν/cm−1: 3086, 1667, 1275,
809; HRMS (ESI): m/z [M + H]+ calcd for C20H11Cl3NO2S: 417.9627,
found: 417.9618.
2
2
(100 MHz, CDCl3) δ 117.7 (d, JC-F = 22.0 Hz), 120.0 (d, JC-F
=
13.0 Hz), 120.8, 124.1, 124.8, 127.0, 128.3, 128.9, 131.5, 132.0 (d,
3JC-F = 9.0 Hz), 132.7, 136.9 (d, JC-F = 6.0 Hz), 137.5, 142.3, 150.5,
3
158.8, 160.1 (d, 1JC-F = 253.0 Hz), 195.8; IR (KBr) ν/cm−1: 2956, 1671,
1309, 722; HRMS (ESI): m/z [M + H]+ calcd for C20H12ClFNOS:
368.0312, found: 368.0315.
(3-Fluoro-2-(6-fluorobenzo[d]thiazol-2-yl)phenyl)(phenyl)methan-
one (3i): Colourless solid; 74% yield; m.p. 124–125 °C; H NMR
(400 MHz, CDCl3) δ 7.08 (t, J = 8.8 Hz, 1H), 7.28 (t, J = 7.6 Hz, 2H),
1
7.34–7.41 (m, 3H), 7.47 (d, J = 8.0 Hz, 1H), 7.56–7.61 (m, 1H),
7.67–7.73 (m, 3H); 13C NMR (100 MHz, CDCl3) δ 107.3 (d, JC-F
=
2
27.0 Hz), 114.9 (d, 2JC-F = 25.0 Hz), 117.6 (d, 2JC-F = 22.0 Hz), 120.1
3
3
(d, JC-F = 13.0 Hz), 124.4 (d, JC-F = 9.0 Hz), 124.8, 128.3, 128.9,
131.8 (d, JC-F = 9.0 Hz), 132.7, 136.9, 137.5, 142.3, 148.6, 158.1,
160.0 (d, JC-F = 252.0 Hz), 160.6 (d, JC-F = 245.0 Hz), 195.9; IR
(KBr) ν/cm−1: 2919, 1665, 1279, 7788; HRMS (ESI): m/z [M + H]+
calcd for C20H12F2NOS: 352.0608, found: 352.0612.
(3-Methyl-2-(6-methylbenzo[d]thiazol-2-yl)phenyl)(phenyl)methan-
one (3j): Brown solid; 30% yield; m.p. 70–71 °C; 1H NMR
(400 MHz, CDCl3) δ 2.43 (s, 3H), 2.45 (s, 3H), 7.22 (d, J = 8.4 Hz,
1H), 7.28 (t, J = 7.6 Hz, 2H), 7.38–7.44 (m, 2H), 7.46–7.49 (m, 2H),
7.57 (s, 1H), 7.69 (d, J = 7.2 Hz, 2H), 7.80 (d, J = 8.0 Hz, 1H); 13C
NMR (100 MHz, CDCl3) δ 20.5, 21.5, 121.0, 122.8, 126.5, 127.6,
128.0, 129.2, 129.9, 132.6, 132.7, 132.8, 135.3, 136.4, 137.4, 138.2,
140.7, 151.1, 164.0, 197.4; IR (KBr) ν/cm−1: 2919, 1668, 1275, 774;
HRMS (ESI): m/z [M + H]+ calcd for C22H18NOS: 344.1109, found:
344.1111.
3
1
1
(2-(6-Chlorobenzo[d]thiazol-2-yl)-3-methylphenyl)(phenyl)methan-
one (3k): White solid (67% yield; m.p. 122–123 °C; 1H NMR
(400 MHz, CDCl3) δ 2.43 (s, 3H), 7.30 (t, J = 7.6 Hz, 2H), 7.37 (d,
J = 8.8 Hz,1H), 7.39–7.44 (m, 2H), 7.49 (d, J = 3.6 Hz, 2H), 7.69 (d,
J = 7.6 Hz, 2H), 7.76 (s, 1H), 7.83 (d, J = 8.8 Hz, 1H); 13C NMR (100
MHz, CDCl3) δ 20.5, 120.9, 124.1, 126.8, 126.9, 128.1, 129.5, 129.9,
131.2, 132.1, 132.8, 132.9, 137.3, 137.4, 138.2, 140.6, 151.4, 165.8,
197.2; IR (KBr) ν/cm−1: 2920, 1668, 1279, 719; HRMS (ESI): m/z
[M + H]+ calcd for C21H15ClNOS: 364.0563, found: 364.0568.
(2-(6-Fluorobenzo[d]thiazol-2-yl)-3-methylphenyl)(phenyl)methan-
one (3l): Yellow solid; 65% yield; m.p. 132–133 °C; 1H NMR
(400 MHz, CDCl3) δ 2.43 (s, 3H), 7.14 (t, J = 7.6 Hz, 1H), 7.29 (t,
J = 7.6 Hz, 2H), 7.38–7.48 (m, 5H), 6.68 (d, J = 7.6 Hz, 2H), 7.85 (dd,
J = 4.8, 8.4 Hz,1H); 13C NMR (100 MHz, CDCl3) δ 20.5, 107.5 (d,
2JC-F = 26.0 Hz), 114.7 (d, 2JC-F = 25.0 Hz), 124.3 (d, 3JC-F = 10.0 Hz),
126.7, 128.1, 129.4, 129.9, 132.2, 132.8, 132.9, 137.2 (d, JC-F
3
=
1
11.0 Hz), 137.4, 138.2, 140.6, 149.5, 160.4 (d, JC-F = 245.0 Hz),
165.0, 197.2; IR (KBr) ν/cm−1: 2962, 1668, 1282, 849; HRMS (ESI):
m/z [M + H]+ calcd for C21H15FNOS: 348.0858, found: 348.0862.
(2-(Benzo[d]thiazol-2-yl)-4-methylphenyl)(phenyl)methanone
(3m): White solid; 76% yield; m.p. 129–130 °C; 1H NMR (400 MHz,
CDCl3) δ 2.52 (s, 3H), 7.25–7.30 (m, 3H), 7.32–7.39 (m, 2H), 7.41
(s, 7.41), 7.45 (d, J = 7.6 Hz, 1H), 7.73–7.81 (m, 5H); 13C NMR
(100 MHz, CDCl3) δ 21.4, 121.4, 123.4, 125.2, 126.1, 128.2, 129.1,
129.3, 130.3, 131.0, 132.3, 132.6, 135.4, 137.0, 138.0, 140.6, 153.5,
165.6, 197.7; IR (KBr) ν/cm−1: 3022, 1663, 1281, 732; HRMS (ESI):
m/z [M + H]+ calcd for C21H16NOS: 330.0953, found: 330.0949.
(2-(6-Chlorobenzo[d]thiazol-2-yl)-4-methylphenyl)(phenyl)methan-
one (3n): Yellow solid; 63%), m.p. 125–126 °C; 1H NMR (400 MHz,
CDCl3) δ 2.52 (s, 3H), 7.25–7.32 (m, 3H), 7.35–7.46 (m, 3H), 7.68 (d,
J = 8.4 Hz, 1H), 7.69 (s, 1H), 7.71–7.76 (m, 3H); 13C NMR (100 MHz,
CDCl3) δ 21.4, 121.0, 124.1, 127.0, 128.2, 129.2, 130.2, 131.1, 131.2
131.9, 132.7, 136.5, 137.0, 137.9, 140.8, 152.0, 166.1, 197.5; IR
(KBr) ν/cm−1: 1683, 1292, 814; HRMS (ESI): m/z [M + H]+ calcd for
C21H15ClNOS: 364.0563, found: 364.0567.
(2-(6-Fluorobenzo[d]thiazol-2-yl)-4-methylphenyl)(phenyl)methan-
one (3o): Yellow solid; 62% yield; m.p. 138–139 °C; 1H NMR
(400 MHz, CDCl3) δ 2.51 (s, 3H), 7.08 (t, J = 8.8 Hz, 1H), 7.28 (t,
J = 7.6 Hz, 2H), 7.35–7.46 (m, 4H), 7.68 (s, 1H), 7.70–7.75 (m, 3H);
13C NMR (100 MHz, CDCl3) δ 21.4, 107.6 (d, 2JC-F = 27.0 Hz), 114.8
(4-Bromophenyl)(3-chloro-2-(6-chlorobenzo[d]thiazol-2-yl)-
phenyl)methanone (3w): Yellow solid; 65% yield; m.p. 133–134 °C;

JOURNAL OF CHEMICAL RESEARCH 2013 267
1H NMR (400 MHz, CDCl3) δ 7.36 (dd, J = 2.0, 8.8 Hz, 1H), 7.42 (d,
J = 8.4 Hz, 2H), 7.46 (dd, J = 1.2, 7.6 Hz, 1H), 7.52 (d, J = 8.8Hz, 2H),
7.55 (t, J = 8.0 Hz, 1H), 7.70 (dd, J = 1.2, 8.0 Hz, 1H), 7.76 (d, J =
8.4 Hz, 1H),7.80 (d, J = 1.6 Hz,1H); 13C NMR (100 MHz, CDCl3)
δ 121.0, 124.3, 127.1, 127.4, 128.2, 130.8, 130.9, 131.2, 131.6, 131.8,
132.3, 134.1, 135.7, 137.4, 142.4, 150.5, 162.4, 194.6; IR (KBr)
ν/cm−1: 3084, 1671, 781; HRMS (ESI): m/z [M + H]+ calcd for
C20H11BrCl2NOS: 461.9122, found: 461.9118.
4-(3-Chloro-2-(6-chlorobenzo[d]thiazol-2-yl)benzoyl)benzonitrile
(3x): Yellow solid; 62% yield; m.p. 142–143 °C; 1H NMR (400 MHz,
CDCl3) δ 7.37 (d, J = 8.8 Hz, 1H), 7.48–7.55 (m, 3H), 7.59 (t, J =
8.0 Hz, 1H), 7.65–7.79 (m, 4H); 13C NMR (100 MHz, CDCl3) δ 115.7,
117.8, 121.0, 124.0, 127.3, 127.7, 128.8, 129.1, 130.9, 131.2, 132.0,
132.8, 133.9, 137.3, 140.4, 141.9, 150.1, 162.0, 167.8, 194.1; IR
(KBr) ν/cm−1: 3084, 1671, 781; HRMS (ESI): m/z [M + H]+ calcd for
C21H11Cl2N2OS: 408.9969, found: 408.9976.
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1
(3y): Brown oil (19% yield;; H NMR (400 MHz, CDCl3) δ 0.82 (t,
J = 7.6 Hz, 3H), 1.56–1.61 (m, 2H), 2.60 (t, J = 7.2 Hz, 2H), 7.48 (dd,
J = 2.0, 8.4 Hz, 1H), 7.53 (d, J = 7.6 Hz, 1H), 7.57 (d, J = 7.6 Hz, 1H),
7.64 (d, J = 8.0 Hz, 1H), 7.93 (d, J = 2.0 Hz, 1H), 7.98 (d, J = 8.8 Hz,
1H); 13C NMR (100 MHz, CDCl3) δ 13.7, 17.6, 43.9, 121.2, 124.4,
126.3, 127.2, 130.6, 131.1, 131.7, 132.3, 134.8, 137.7, 143.5, 151.1,
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Financial Supported from National Natural Science Founda-
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(GJJ12169), and Open Project Program of Key Laboratory of
Functional Small Organic Molecule, Ministry of Education,
Jiangxi Normal University (No. KLFS-KF-201217) is grate-
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Received 28 January 2013; accepted 15 February 2013
Paper 1301759 doi: 10.3184/174751913X13639769724276
Published online: 15 May 2013

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