Synthesis and insecticidal activity of novel benzothiazole derivatives containing the coumarin moiety

Article abstract of DOI:10.24820/ark.5550190.p010.664

A series of novel benzothiazole derivatives containing a coumarin moiety was designed and synthesized. Their structures were characterized in detail via ¹H NMR, ¹³C NMR, HRMS spectra and single-crystal X-ray diffraction analysis. The bioassay results indicated that some compounds showed encouraging insecticidal activity against Plutella xylostella and Aphis fabae at 400 mg/L. The preliminary structure-activity relationships were also discussed.

Full text of DOI:10.24820/ark.5550190.p010.664

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Synthesis and insecticidal activity of novel benzothiazole derivatives containing
the coumarin moiety
Wei-Jie Si,a,b,c Min Chen,a,b Xue-Lun Wang,a,b Meng-Qi Wang,a,b Jian Jiao,a,b
Xin-Can Fu,a,b and Chun-Long Yang*a,b,c
a Department of Chemistry, College of Sciences, Nanjing Agricultural University, Nanjing 210 095, China
b Jiangsu Key Laboratory of Pesticide Science, Nanjing Agricultural University, Nanjing 210 095, China
c Key Laboratory of Monitoring and Management of Crop Diseases and Insect Pests, Ministry of Agriculture,
Nanjing Agricultural University, Nanjing 210 095, China
Email: ycl@njau.edu.cn
Received 06-19-2018
Accepted 08-06-2018
Published on line 09-06-2018
Abstract
A series of novel benzothiazole derivatives containing a coumarin moiety was designed and synthesized. Their
structures were characterized in detail via 1H NMR, 13C NMR, HRMS spectra and single-crystal X-ray diffraction
analysis. The bioassay results indicated that some compounds showed encouraging insecticidal activity against
Plutella xylostella and Aphis fabae at 400 mg/L. The preliminary structure-activity relationships were also
discussed.
Keywords: Synthesis, benzothiazole, coumarin, insecticidal activity, structure-activity relationship
DOI: https://doi.org/10.24820/ark.5550190.p010.664
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Introduction
The growth, transportation and storage of crops are endangered by various agricultural diseases, insects,
grasses, and rats. These agricultural harmful organisms have seriously affected the growth of crops, the
appearance, yield and quality of agricultural products. Because agricultural pests are characterized by many
types, large quantities, and serious damage, it is an important task in agricultural production to control
agricultural pests and reduce their damage.1 Pesticides have played an important role in the prevention and
control of agricultural pests. However, drug resistances, environmental hazards and other problems have
become increasingly prominent with the use of insecticides,2,3 which objectively require the discovery of new
insecticide candidates.
Benzothiazole derivatives exhibit a wide variety of biological activities such as anticancer,4 analgesic,5 anti-
inflammatory,6 anti-tubercular,7 antimicrobial,8 and insecticidal activity.9 The compounds A and B (Figure 1)
containing benzothiazole moiety possessed insecticidal activity against Prodenia litura and Plutella xylostella,
respectively.10,11 The compound C containing phenyl benzothiazole moiety showed acaricidal activity.12
Coumarins are frequently used to develop novel lead compounds for agrochemical and pharmaceutical
because of their wide spectrum of bioactivities.13 Coumarin derivatives have often acted as anticancer
prodrugs,14 or as antimalarial,15 anti-inflammatory,16 antioxidant and antimicrobial agents.17 In particular,
compounds D and E, which both contain coumarin skeleton in their structures have been reported to show
insecticidal activity.18,19 However, almost no coumarin insecticides have actually been used to control
agricultural insects. So the design and synthesis of the compounds containing the coumarin moiety is very
meaningful for the development of novel insecticides with unique molecular skeleton.
In view of the above reports, two pharmacophores benzothiazole and coumarin were connected by an
alkylene linker in the same molecule to design and synthesize a series of benzothiazole derivatives containing
the coumarin group according to the "active substructure combination principle" (Figure 1). Subsequently, the
insecticidal activity against Plutella xylostella and Aphis fabae (broad bean aphid) were evaluated. The
preliminary structure-activity relationships between the title compounds and insecticidal activity were also
analyzed.
Figure 1. Design of target compounds.
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Results and Discussion
Chemistry. Schemes 1 and 2 describe the synthesis and structures of the intermediates and title compounds in
the present study. Firstly, resorcinol 1 was reacted with 2-hydroxysuccinic acid and ethyl acetoacetate
respectively to generate the corresponding coumarin intermediates 7-hydroxy-2H-chromen-2-one 2a and 7-
hydroxy-4-methyl-2H-chromen-2-one 2b. 2-Aminothiophenol was reacted respectively with 4-
hydroxybenzaldehyde, vanillin and 3-hydroxybenzaldehyde in the presence of sodium metabisulfite to obtain
the benzothiazole intermediates 4a–4c. Then the compounds 4 were treated respectively with
dibromoalkanes (Br(CH2)nBr, n=2–6) in the presence of K2CO3 to provide the brominated intermediates 5a–5o.
Finally, the compounds 5 were reacted with compounds 2a and 2b respectively to get the target products 6a–
6z and 6aa–6dd with yields ranging from 44.6% to 78.3%.
HO CHCOOH
CH COOH
2
OH
o
H SO (excess), 100
2
4
HO
O
O
2a
O
O
OH
1
O
o
H SO (cat.), 1,4-dioxane, 60
2
4
HO
O
O
2b
Scheme 1. Synthesis of intermediate compounds 2a and 2b.
Scheme 2. Synthesis route of title compounds 6a–6z and 6aa–6dd.
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1
The H NMR, 13C NMR, and HRMS spectra data of the title compounds were fully in accordance with their
1
assigned structures. The structures of some key intermediates were also confirmed by H NMR spectra. The
yields, melting points and spectra data of the title compounds and intermediates are listed in the Experimental
Section. This is the first report of all of the title compounds.
Crystal structure of compound 6v. The structure of compound 6v was further studied using the single crystal
X-ray analysis. The corresponding crystal structure and crystal packing diagrams are shown by Figure 2. and
Figure 3, respectively. As shown in Figure 2, the sulfur and nitrogen atoms of the benzothiazole ring appeared
in a disordered state. Thus two corresponding intramolecular hydrogen bonds C9–H9···S1' and C13–H13···S1
were formed. As shown in Figure 3, three intermolecular hydrogen bonds C5–H5···S1, C12–H12···O1 and C23–
H23···O4 were found. In addition, there were two offset face-to-face π···π stacking interactions between
benzothiazole and chromene rings of two adjacent molecules. The intermolecular hydrogen bonds connected
the molecules in the planes which were nearly perpendicular to the vector b. The π···π interactions made the
molecules packed through the direction of vector b. These two actions made the molecules formed a 3-D
supramolecular network structure. The crystal data for 6v: triclinic, a = 6.5984(9) Å, b = 7.2742(12) Å, c =
22.5363(19) Å, α = 90.238(10) °, β = 91.143(9) °, γ = 115.337(15) °, V = 977.4(3) Å3, Z = 2, space group P-1 (no.2),
μ = 0.201 mm-1, Dcalc = 1.460 g/cm3, 7766 reflections measured (5.4≤2θ≤52.8), 4000 unique (Rint = 0.048) were
used in all calculations. The final R1 was 0.0806 (I > 2σ(I)) and wR(F2) was 0.2119 (all data). The crystallographic
data have been deposited with the Cambridge Crystallographic Data Centre. The deposition number was
CCDC1838383.
Yellow dashed lines show intramolecular hydrogen bonds.
Figure 2. Crystal structure diagram of compound 6v.
Yellow dashed lines show intermolecular hydrogen bonds. Red dashed lines show π···π interactions.
Figure 3. Crystal packing diagram of compound 6v.
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Insecticidal activity. The results in Table 1 indicated that the title compounds showed moderate to significant
insecticidal activity at 400 μg/mL. Ten of the compounds showed high activity with the mortalities of more
than 50% against P. xylostella. Among them, the compounds 6d, 6k, 6w and 6z possessed the mortalities of
over 85%, especially the compounds 6d and 6w, which reached 100% and 93.10% mortalities, respectively.
Meanwhile, twenty-three of the compounds showed high activity against the aphids, their mortalities were
higher than 50%. While the compounds 6e, 6l, 6s, 6t and 6u presented noticeable activity with the mortalities
of 90% above. Compared with the activity against P. xylostella, the title compounds showed higher insecticidal
activity against A. fabae. Among them, the compounds 6u–6z and 6aa–6dd gave good activity against the
aphids with the mortalities ranging from 56.67 to 96.51%. That is to say, the alkylene linked at 3-position of
benzothiazol-2-phenyl was beneficial to the bioactivity against the aphids. In addition, the compounds 6c, 6h,
6m, 6r, 6w and 6bb all exhibited evident activity against the aphids with the mortalities ranging from 60.00 to
88.41%. These six compounds contain a same alkylene linker with four carbon atoms (n=4).
Table 1. Insecticidal activity in vivo of title compounds at 400 μg/mL
Mortality (%)
P. x.a
Mortality (%)
P. x.
Compd.
Compd.
A. f.b
A. f.
6a
6b
6c
6d
6e
6f
6g
6h
6i
6j
6k
6l
6m
6n
6o
6p
32.26±3.23
40.63±1.56
43.75±4.69
100
30.00±2.50
80.57±3.43
71.88±3.13
54.84±1.08
92.13±2.25
24.49±4.08
22.58±2.15
60.00±1.54
60.98±4.88
26.09±4.35
24.74±3.09
94.34±4.72
87.72±5.26
27.94±2.94
53.62±4.35
74.58±3.39
6q
6r
6s
6t
6u
6v
6w
6x
6y
6z
6aa
6bb
6cc
6dd
Ch.c
Im.d
13.33±1.67
48.28±3.45
84.38±3.13
6.90±1.72
13.33±1.67
43.33±5.00
93.10±3.45
31.03±1.72
26.67±3.33
86.21±6.90
63.33±6.67
12.50±3.13
64.52±4.84
38.71±6.45
100
16.22±2.70
85.51±4.35
96.47±3.53
96.51±3.49
96.51±2.33
71.72±3.03
76.47±3.92
56.67±4.44
84.15±2.44
58.54±3.66
89.87±5.06
88.41±4.35
68.42±3.51
86.76±4.41
100
59.38±3.13
50.00±5.00
15.63±1.56
48.48±4.55
19.35±1.61
73.33±3.33
86.67±1.67
35.48±4.84
13.33±3.33
26.67±3.33
3.33±1.67
10.00±1.67
100
100
a P.x., Plutella xylostella; b A.f., Aphis fabae; c Ch., chlorantraniliprole; d Im., imidacloprid.
Conclusions
In summary, a series of novel benzothiazole derivatives containing a coumarin group were designed, prepared
and evaluated for their insecticidal activities against Plutella xylostella and Aphis fabae in vivo. The structures
of title compounds were well supported by spectroscopic data and single-crystal X-ray diffraction analysis. The
compounds 6d and 6w showed outstanding activity against P. xylostella. And the compounds 6e, 6l, 6s, 6t and
6u possessed good activity against A. fabae. The structure-activity relationship analysis demonstrated that the
alkylene was linked at 3-position of benzothiazol-2-phenyl was beneficial to improve the bioactivity of title
compounds against the aphids. Meanwhile, the compounds containing a alkylene linker with four carbon
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atoms would show better insecticidal activity. The results provided a practical guidance for further
modification and optimization of the structures of title compounds.
Experimental Section
General. The melting points of the products were determined on a WRS-1B digital melting-point apparatus.
NMR spectra were performed in DMSO-d6 or CDCl3 on a Bruker Avance III 400 NMR spectrometer at room
temperature with TMS as an internal standard. Thin-layer chromatography (TLC) was performed on silica gel
GF254. High resolution mass spectrometry was recorded on an Agilent Technologies 6540 UHD Accurate-Mass
Q-TOF LC/MS. All reagents were analytical reagent grade pure and used directly without further purification.
Synthesis of coumarin intermediates 2. 7-Hydroxy coumarin 2a was synthesized according to the reported
literature.20 Resorcinol (11.0 g, 0.1 mol) and 2-hydroxysuccinic acid (20.1 g, 0.15 mol) were added to a stirred
solution of concentrated sulfuric acid (200 mL) in a reaction flask equipped with a thermometer and addition
o
funnel. The reaction mixture was maintained at 100 C for 2.5 h and poured into crushed ice under vigorous
stirring. The off-white precipitate was filtered and purified by recrystallization from ethanol to give the
product 2a. Another coumarin intermediate 7-hydroxy-4-methyl-2H-chromen-2-one 2b was prepared under
relatively mild conditions by condensing resorcinol with ethyl acetoacetate in the presence of a catalytic
amount of concentrated sulfuric acid in 1,4-dioxane at 60 oC for 4 h. (see Supplementary file.)
Synthesis of benzothiazole intermediates 4. Sodium metabisulfite (0.49 g, 2.5 mmol) was added to a DMF
solution of 2-aminothiophenol (2.50 g, 20 mmol) and 4-hydroxybenzaldehyde (2.46 g, 20.2 mmol ). The
reaction mixture was stirred and heated to reflux for 2–2.5 h. The progress of reaction was monitored
periodically by TLC for completion. Then the mixture was poured into crushed ice, the formed precipitate was
separated by filtration and washing to obtain 4-(benzothiazol-2-yl)phenol 4a. Other benzothiazole
intermediates 4-(benzothiazol-2-yl)-2-methoxyphenol 4b and 3-(benzothiazol-2-yl)phenol 4c were prepared
using a similar synthetic method.21 (see Supplementary file.)
Synthesis of bromoalkyl intermediates 5. 1,2-Dibromoethane (4.5 g, 24 mmol) was added to a solution of 4a
(1.36 g, 6 mmol) and K2CO3 (2.48 g, 18 mmmol) in acetone (50 mL). The mixture was stirred at reflux for 4–6 h.
The reaction solution was then filtered and concentrated under reduced pressure. The obtained viscous liquid
was purified by column chromatography to give a yellow solid 2-[4-(2-bromoethoxy)phenyl]benzothiazole 5a.
The above synthetic method was also used to prepare other bromoalkyl intermediates 5b–5o. (see
Supplementary file.)
Synthesis of title compounds 6. The mixture of 5a (0.54 g, 1.6 mmol), 2a (0.26 g, 1.6 mmol) and anhydrous
K2CO3 (0.41g, 3 mmol) in DMF (25 mL) was heated at 60–70 oC for 6 h. The reaction solution was then poured
into crushed ice. The precipitate was filtered and purified by column chromatography with the mixed solution
of ethyl acetate and petroleum ether (v/v 1: 2) to yield the title compound 6a. The preparation method of
target compounds 6b–6dd was similar to that of 6a.
7-{2-[4-(Benzothiazol-2-yl)phenoxy]ethoxy}-2H-chromen-2-one (6a). White powder; yield 60.3%; mp 217–
o
1
218 C; H NMR (400 MHz, DMSO-d6) δ: 8.11 (t, J 8.1 Hz, 1H, Benzothiazole-4-H), 8.09–7.95 (m, 4H,
Benzothiazole-7-H, Benzothiazol-2-phenyl-2,6-2H, Coumarin-4-H), 7.66 (d, J 8.6 Hz, 1H,Coumarin-5-H), 7.53 (t,
J 7.5 Hz, 1H, Benzothiazole-5-H), 7.44 (t, J 7.4 Hz, 1H, Benzothiazole-6-H), 7.19 (d, J 8.6 Hz, 2H, Benzothiazol-2-
phenyl-3,5-2H), 7.10 (s, 1H, Coumarin-8-H), 7.03 (d, J 8.5 Hz, 1H, Coumarin-6-H), 6.32 (d, J 9.5 Hz, 1H,
Coumarin-3-H), 4.49 (s, 4H,2 x CH2); 13C NMR (101 MHz, CDCl3) δ: 167.6, 161.7, 161.0, 160.7, 155.8, 154.1,
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143.3, 134.8, 129.1, 128.8, 127.0, 126.2, 124.9, 122.8, 121.5, 116.9, 115.0, 113.4, 113.0, 112.9, 101.6, 66.9,
66.3; HRMS (ESI) m/z for C24H18NO4S [M+H]+ calcd. 416.0957, found. 416.0948.
7-{3-[4-(Benzothiazol-2-yl)phenoxy]propoxy}-2H-chromen-2-one (6b). White powder; yield 64.5%; mp 175–
o
1
176 C; H NMR (400 MHz, DMSO-d6) δ: 8.12 (d, J 7.9 Hz, 1H, Benzothiazole-4-H), 8.07–7.96 (m, 4H,
Benzothiazole-7-H, Benzothiazol-2-phenyl-2,6-2H, Coumarin-4-H), 7.64 (d, J 8.6 Hz, 1H, Coumarin-5-H), 7.53 (t,
J 7.2 Hz, 1H, Benzothiazole-5-H), 7.43 (t, J 7.6 Hz, 1H, Benzothiazole-6-H), 7.16 (d, J 8.8 Hz, 2H, Benzothiazol-2-
phenyl-3,5-2H), 7.05 (d, J 2.2 Hz, 1H, Coumarin-8-H), 7.00 (dd, J 8.6, 2.3 Hz, 1H, Coumarin-6-H), 6.30 (d, J 9.5
Hz, 1H, Coumarin-3-H), 4.27 (dd, J 14.1, 6.3 Hz, 4H, 2 x CH2), 2.29–2.20 (m, 2H, CH2); 13C NMR (101 MHz, CDCl3)
δ: 167.7, 162.0, 161.1, 161.0, 155.8, 154.2, 143.3, 134.8, 129.1, 128.8, 126.6, 126.2, 124.8, 122.8, 121.5, 114.8,
113.1, 112.8, 112.6, 101.5, 64.9, 64.3, 28.9; HRMS (ESI) m/z for C25H20NO4S [M+H]+ calcd. 430.1113, found.
430.1104.
7-{4-[4-(Benzothiazol-2-yl)phenoxy]butoxy}-2H-chromen-2-one (6c).White powder; yield 60.5%; mp 158–160
1
oC; H NMR (400 MHz, DMSO-d6) δ: 8.11 (d, J 7.9 Hz, 1H, Benzothiazole-4-H), 8.02 (dd, J 14.2, 9.0 Hz, 4H,
Benzothiazole-7-H, Benzothiazol-2-phenyl-2,6-2H, Coumarin-4-H), 7.63 (d, J 8.6 Hz, 1H, Coumarin-5-H), 7.53 (t,
J 7.4 Hz, 1H, Benzothiazole-5-H), 7.43 (t, J 7.5 Hz, 1H, Benzothiazole-6-H), 7.13 (d, J 8.8 Hz, 2H, Benzothiazol-2-
phenyl-3,5-2H), 7.02 (d, J 2.0 Hz, 1H, Coumarin-8-H), 6.97 (dd, J 8.6, 2.3 Hz, 1H, Coumarin-6-H), 6.29 (d, J 9.5
Hz, 1H, Coumarin-3-H), 4.17 (d, J 4.8 Hz, 4H, 2 x CH2), 1.93 (s, 4H, 2 x CH2); 13C NMR (101 MHz, CDCl3) δ: 167.8,
162.2, 161.2, 155.9, 154.2, 143.4, 134.8, 129.1, 128.7, 126.4, 126.2, 124.8, 122.8, 121.5, 114.8, 113.0, 112.9,
112.5, 101.3, 68.1, 67.5, 25.8, 25.8; HRMS (ESI) m/z for C26H22NO4S [M+H]+ calcd. 444.1270, found. 444.1260.
7-{5-[4-(Benzothiazol-2-yl)phenoxy]pentyloxy}-2H-chromen-2-one (6d). Grey powder; yield 68.4%; mp 149–
o
151 C; 1H NMR (400 MHz, DMSO-d6) δ: 8.11 (t, J 6.5 Hz, 1H, Benzothiazole-4-H), 8.06–7.96 (m, 4H,
Benzothiazole-7-H, Benzothiazol-2-phenyl-2,6-2H, Coumarin-4-H), 7.62 (d, J 8.6 Hz, 1H, Coumarin-5-H), 7.52
(dd, J 11.2, 4.1 Hz, 1H, Benzothiazole-5-H), 7.43 (t, J 7.1 Hz, 1H, Benzothiazole-6-H), 7.12 (d, J 8.8 Hz, 2H,
Benzothiazol-2-phenyl-3,5-2H), 7.00 (d, J 2.2 Hz, 1H, Coumarin-8-H), 6.96 (dd, J 8.6, 2.3 Hz, 1H, Coumarin-6-H),
6.28 (d, J 9.5 Hz, 1H, Coumarin-3-H), 4.11 (dd, J 10.4, 6.2 Hz, 4H, 2 x CH2), 1.83 (dt, J 13.4, 6.5 Hz, 4H, 2 x CH2),
1.60 (dt, J 14.8, 7.4 Hz, 2H, CH2); 13C NMR (101 MHz, CDCl3) δ: 167.8, 162.2, 161.3, 161.2, 155.8, 154.2, 143.4,
134.8, 129.0, 128.7, 126.2, 126.2, 124.8, 122.7, 121.5, 114.8, 112.8, 112.4, 101.3, 68.3, 67.8, 28.8, 28.7, 22.6;
HRMS (ESI) m/z for C27H24NO4S [M+H]+ calcd. 458.1426, found. 458.1420.
7-{6-[4-(Benzothiazol-2-yl)phenoxy]hexyloxy}-2H-chromen-2-one (6e). Grey powder; yield 57.8%; mp 143–
o
1
144 C; H NMR (400 MHz, DMSO-d6) δ: 8.11 (d, J 7.9 Hz, 1H, Benzothiazole-4-H), 8.06–7.94 (m, 4H,
Benzothiazole-7-H, Benzothiazol-2-phenyl-2,6-2H, Coumarin-4-H), 7.62 (d, J 8.6 Hz, 1H, Coumarin-5-H), 7.52 (t,
J 7.6 Hz, 1H, Benzothiazole-5-H), 7.43 (t, J 7.5 Hz, 1H, Benzothiazole-6-H), 7.11 (d, J 8.7 Hz, 2H, Benzothiazol-2-
phenyl-3,5-2H), 6.98 (s, 1H, Coumarin-8-H), 6.97 – 6.92 (m, 1H, Coumarin-6-H), 6.28 (d, J 9.5 Hz, 1H, Coumarin-
3-H), 4.08 (d, J 3.7 Hz, 4H, 2 x CH2), 1.78 (s, 4H, 2 x CH2), 1.50 (s, 4H, 2 x CH2); 13C NMR (101 MHz, CDCl3) δ:
167.9, 162.3, 161.4, 161.2, 155.9, 154.2, 143.4, 134.8, 129.1, 128.7, 126.2, 126.2, 124.7, 122.7, 121.5, 114.8,
112.9 (d, J = 1.9 Hz), 112.4, 101.3, 68.4, 67.9, 29.0, 28.9, 25.8, 25.7; HRMS (ESI) m/z for C28H26NO4S [M+H]+
calcd. 472.1583, found. 472.1576.
7-{2-[4-(Benzothiazol-2-yl)phenoxy]ethoxy}-4-methyl-2H-chromen-2-one (6f). White powder; yield 62.3%;
mp 227–228 oC; 1H NMR (400 MHz, DMSO-d6) δ: 8.13 (d, J 7.8 Hz, 1H, Benzothiazole-4-H), 8.04 (dd, J 15.4, 8.3
Hz, 3H, Benzothiazole-7-H, Benzothiazol-2-phenyl-2,6-2H), 7.72 (d, J 8.7 Hz, 1H, Coumarin-5-H), 7.53 (t, J 7.5 Hz,
1H, Benzothiazole-5-H), 7.44 (t, J 7.5 Hz, 1H, Benzothiazole-6-H), 7.21 (t, J 7.2 Hz, 2H, Benzothiazol-2-phenyl-
3,5-2H), 7.10 (d, J 2.2 Hz, 1H, Coumarin-8-H), 7.05 (d, J 8.7 Hz, 1H, Coumarin-6-H), 6.24 (s, 1H, Coumarin-3-H),
4.49 (s, 4H, 2 x CH2), 2.42 (s, 3H,CH3); 13C NMR (101 MHz, CDCl3) δ: 167.6, 161.5, 161.2, 160.7, 155.1, 154.1,
152.4, 134.8, 129.2, 127.0, 126.2, 125.6, 124.9, 122.8, 121.5, 116.9, 115.0, 114.0, 112.7, 112.2, 101.6, 66.9,
66.4, 18.6; HRMS (ESI) m/z for C25H20NO4S [M+H]+ calcd. 430.1113, found. 430.1105.
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7-{3-[4-(Benzothiazol-2-yl)phenoxy]propoxy}-4-methyl-2H-chromen-2-one (6g). White powder; yield 66.8%;
mp 129–132 oC; 1H NMR (400 MHz, DMSO-d6) δ: 8.11 (d, J 7.8 Hz, 1H, Benzothiazole-4-H), 8.02 (t, J 8.4 Hz, 3H,
Benzothiazole-7-H, Benzothiazol-2-phenyl-2,6-2H), 7.68 (d, J 8.7 Hz, 1H, Coumarin-5-H), 7.52 (t, J 7.2 Hz, 1H,
Benzothiazole-5-H), 7.43 (t, J 7.3 Hz, 1H, Benzothiazole-6-H), 7.15 (d, J 8.8 Hz, 2H, Benzothiazol-2-phenyl-3,5-
2H), 7.05–6.95 (m, 2H, Coumarin-6,8-2H), 6.21 (s, 1H, Coumarin-3-H), 4.27 (dd, J 13.3, 6.4 Hz, 4H, 2 x CH2),
2.39 (s, 3H,CH3), 2.29–2.17 (m, 2H,CH2); 13C NMR (101 MHz, CDCl3) δ: 167.7, 161.8, 161.2, 161.1, 155.2, 154.1,
152.5, 134.8, 129.1, 126.5, 126.2, 125.5, 124.8, 122.8, 121.5, 114.8, 113.6, 112.4, 111.9, 101.5, 64.8, 64.3, 28.9,
18.6; HRMS (ESI) m/z for C26H22NO4S [M+H]+ calcd. 444.1270, found. 444.1260.
7-{4-[4-(Benzothiazol-2-yl)phenoxy]butoxy}-4-methyl-2H-chromen-2-one (6h). White powder; yield 67.5%;
o
mp 175–178 C;1H NMR (400 MHz, DMSO-d6) δ: 8.12 (d, J 7.9 Hz, 1H, Benzothiazole-4-H), 8.02 (t, J 7.9 Hz, 3H,
Benzothiazole-7-H, Benzothiazol-2-phenyl-2,6-2H), 7.68 (d, J 8.7 Hz, 1H, Coumarin-5-H), 7.52 (dd, J 11.2, 4.1 Hz,
1H, Benzothiazole-5-H), 7.43 (t, J 7.6 Hz, 1H, Benzothiazole-6-H), 7.13 (d, J 8.8 Hz, 2H, Benzothiazol-2-phenyl-
3,5-2H), 7.04–6.93 (m, 2H, Coumarin-6,8-2H), 6.21 (d, J 0.9 Hz, 1H, Coumarin-3-H), 4.16 (t, J 11.0 Hz, 4H, 2 x
CH2), 2.40 (s, 3H, CH3), 1.93 (s, 4H, 2 x CH2); 13C NMR (101 MHz, CDCl3) δ: 167.8, 161.9, 161.3, 161.2 , 155.2,
154.2, 152.6, 134.8, 129.1, 126.4, 126.2, 125.5, 124.8, 122.8, 121.5, 114.8, 113.5, 112.5, 111.8, 101.3, 68.0,
67.6, 25.8, 25.8, 18.6; HRMS (ESI) m/z for C27H24NO4S [M+H]+ calcd. 458.1426, found. 458.1419.
7-{5-[4-(Benzothiazol-2-yl)phenoxy]pentyloxy}-4-methyl-2H-chromen-2-one (6i). Grey powder; yield 54.5%;
o
1
mp 132–134 C; H NMR (400 MHz, DMSO-d6) δ: 8.11 (d, J 7.8 Hz, 1H, Benzothiazole-4-H), 8.02 (dd, J 7.8, 4.3
Hz, 3H, Benzothiazole-7-H, Benzothiazol-2-phenyl-2,6-2H), 7.67 (d, J 8.7 Hz, 1H, Coumarin-5-H), 7.52 (t, J 7.4 Hz,
1H, Benzothiazole-5-H), 7.43 (t, J 7.4 Hz, 1H, Benzothiazole-6-H), 7.12 (d, J 8.7 Hz, 2H, Benzothiazol-2-phenyl-
3,5-2H), 7.02–6.92 (m, 2H, Coumarin-6,8-2H), 6.20 (s, 1H, Coumarin-3-H), 4.19–4.03 (m, 4H, 2 x CH2), 2.39 (s,
3H,CH3), 1.92–1.76 (m, 4H, 2 x CH2), 1.68–1.54 (m, 2H, CH2); 13C NMR (101 MHz, CDCl3) δ: 167.8, 162.0, 161.3,
161.3, 155.2, 154.1, 152.6, 134.8, 129.0, 126.2, 126.2, 125.5, 124.8, 122.7, 121.5, 114.8, 113.4, 112.5, 111.7,
101.3, 68.2, 67.8, 28.8, 28.7, 22.6, 18.6; HRMS (ESI) m/z for C28H26NO4S [M+H]+ calcd. 472.1583, found.
472.1576.
7-{6-[4-(Benzothiazol-2-yl)phenoxy]hexyloxy}-4-methyl-2H-chromen-2-one (6j). Yellow-brown powder; yield
o
1
50.2%; mp 156–158 C; H NMR (400 MHz, DMSO-d6) δ: 8.11 (d, J 7.6 Hz, 1H, Benzothiazole-4-H), 7.99 (d, J
21.0 Hz, 3H, Benzothiazole-7-H, Benzothiazol-2-phenyl-2,6-2H), 7.67 (d, J 8.3 Hz, 1H, Coumarin-5-H), 7.52 (d, J
7.5 Hz, 1H, Benzothiazole-5-H), 7.44 (d, J 7.4 Hz, 1H, Benzothiazole-6-H), 7.11 (d, J 8.0 Hz, 2H, Benzothiazol-2-
phenyl-3,5-2H), 6.96 (d, J 11.0 Hz, 2H, Coumarin-6,8-2H), 6.20 (s, 1H, Coumarin-3-H), 4.09 (s, 4H, 2 x CH2), 2.39
(s, 3H,CH3), 1.72 (s, 4H, 2 x CH2), 1.47 (s, 4H, 2 x CH2); 13C NMR (101 MHz, CDCl3) δ: 167.8, 162.1, 161.4, 161.3,
155.2, 154.2, 152.6, 134.8, 129.0, 126.2 , 126.2, 125.5, 124.7, 122.7, 121.5, 114.8, 113.4, 112.6, 111.7, 101.3,
68.3, 67.9, 29.0, 28.9, 25.7, 25.7, 18.6; HRMS (ESI) m/z for C29H28NO4S [M+H]+ calcd. 486.1739, found.
486.1735.
7-{2-[4-(Benzothiazol-2-yl)-2-methoxyphenoxy]ethoxy}-2H-chromen-2-one (6k). White powder; yield 63.7%;
mp 207–208 oC; 1H NMR (400 MHz, DMSO-d6) δ: 8.12 (d, J 8.1 Hz, 1H, Benzothiazole-4-H), 8.03 (t, J 8.1 Hz, 2H,
Benzothiazole-7-H, Coumarin-4-H), 7.71–7.60 (m, 3H, Coumarin-5-H, Benzothiazole-5,6-2H), 7.54 (t, J 7.1 Hz,
1H, Benzothiazol-2-phenyl-6-H), 7.44 (t, J 7.6 Hz, 1H, Benzothiazol-2-phenyl-2-H), 7.22 (d, J 8.4 Hz, 1H,
Coumarin-8-H), 7.13 (d, J 2.3 Hz, 1H, Coumarin-6-H), 7.03 (dd, J 8.6, 2.4 Hz, 1H, Benzothiazol-2-phenyl-5-H),
6.32 (d, J 9.5 Hz, 1H, Coumarin-3-H), 4.50 (d, J 5.1 Hz, 2H,CH2), 4.45 (d, J 4.9 Hz, 2H,CH2), 3.90 (s, 3H,OCH3); 13C
NMR (101 MHz, CDCl3) δ: 167.7, 161.8, 161.1, 155.8, 154.1, 150.4, 149.9, 143.3, 134.9, 128.8, 127.6, 126.3,
125.0, 122.9, 121.5, 120.98, 113.5, 113.4, 113.1, 112.9, 110.4, 101.8, 67.5, 67.0, 56.1; HRMS (ESI) m/z for
C25H20NO5S [M+H]+ calcd. 446.1062, found. 446.1054.
7-{3-[4-(Benzothiazol-2-yl)-2-methoxyphenoxy]propoxy}-2H-chromen-2-one (6l). White powder; yield 61.9%;
mp 161–163 oC; 1H NMR (400 MHz, DMSO-d6) δ: 8.11 (d, J 7.8 Hz, 1H, Benzothiazole-4-H), 8.01 (dd, J 14.6, 8.8
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Hz, 2H, Benzothiazole-7-H, Coumarin-4-H), 7.62 (dd, J 14.3, 11.0 Hz, 3H, Coumarin-5-H, Benzothiazole-5,6-2H),
7.53 (t, J 7.5 Hz, 1H, Benzothiazol-2-phenyl-6-H), 7.43 (t, J 7.4 Hz, 1H, Benzothiazol-2-phenyl-2-H), 7.16 (d, J 8.4
Hz, 1H, Coumarin-8-H), 7.05 (s, 1H, Coumarin-6-H), 6.99 (d, J 8.6 Hz, 1H, Benzothiazol-2-phenyl-5-H), 6.29 (d, J
9.5 Hz, 1H, Coumarin-3-H), 4.32–4.18 (m, 4H, 2 x CH2), 3.91 (s, 3H,OCH3), 2.30–2.18 (m, 2H,CH2); 13C NMR (101
MHz, CDCl3) δ: 167.8, 162.0, 161.2, 155.8, 154.1, 150.7, 149.7, 143.3, 134.9, 128.7, 127.0, 126.2, 124.9, 122.8,
121.5, 121.0, 113.1, 112.8, 112.7, 112.6, 110.2, 101.5, 65.3, 64.9, 56.1, 28.9. HRMS (ESI) m/z for C26H22NO5S
[M+H]+ calcd. 460.1219, found, 460.1209.
7-{4-[4-(Benzothiazol-2-yl)-2-methoxyphenoxy]butoxy}-2H-chromen-2-one (6m). White powder; yield 58.1%;
mp 142–143 oC; 1H NMR (400 MHz, DMSO-d6) δ: 8.11 (d, J 7.9 Hz, 1H, Benzothiazole-4-H), 8.01 (dd, J 14.9, 8.8
Hz, 2H, Benzothiazole-7-H, Coumarin-4-H), 7.68–7.57 (m, 3H, Coumarin-5-H, Benzothiazole-5,6-2H), 7.53 (t, J
7.7 Hz, 1H, Benzothiazol-2-phenyl-6-H), 7.43 (t, J 7.6 Hz, 1H, Benzothiazol-2-phenyl-2-H), 7.15 (d, J 8.4 Hz, 1H,
Coumarin-8-H), 7.01(s, 1H, Coumarin-6-H), 6.97 (d, J 8.6 Hz, 1H, Benzothiazol-2-phenyl-5-H), 6.29 (d, J 9.5 Hz,
1H, Coumarin-3-H), 4.17 (d, J 15.5 Hz, 4H, 2 x CH2), 3.90 (s, 3H, OCH3), 1.94 (s, 4H, 2 x CH2); 13C NMR (101 MHz,
CDCl3) δ: 167.8, 162.2, 161.2, 155.8, 154.1, 150.9, 149.6, 143.4, 134.9, 128.7, 126.7, 126.2, 124.8, 122.8, 121.5,
121.0, 112.9, 112.9, 112.4, 112.3, 110.1, 101.3, 68.5, 68.1, 56.1, 25.9, 25.7; HRMS (ESI) m/z for C27H24NO5S
[M+H]+ calcd. 474.1375, found, 474.1370.
7-{5-[4-(Benzothiazol-2-yl)-2-methoxyphenoxy]pentyloxy}-2H-chromen-2-one (6n). White powder; yield
66.3%; mp 116–118 oC; 1H NMR (400 MHz, DMSO-d6) δ: 8.10 (t, J 6.5 Hz, 1H, Benzothiazole-4-H), 8.06–7.98 (m,
1H, Benzothiazole-7-H), 7.97 (d, J 6.5 Hz, 1H, Coumarin-4-H), 7.61 (ddd, J 10.3, 7.4, 2.0 Hz, 3H, Coumarin-5-H,
Benzothiazole-5,6-2H), 7.53 (t, J 7.7 Hz, 1H, Benzothiazol-2-phenyl-6-H), 7.43 (t, J 7.6 Hz, 1H, Benzothiazol-2-
phenyl-2-H), 7.14 (d, J 8.4 Hz, 1H, Coumarin-8-H), 6.99 (dd, J 8.7, 3.6 Hz, 1H, Coumarin-6-H), 6.96 (dd, J 8.6, 2.4
Hz, 1H, Benzothiazol-2-phenyl-5-H), 6.28 (d, J 9.5 Hz, 1H, Coumarin-3-H), 4.18–3.99 (m, 4H, 2 x CH2), 3.90 (s,
3H, OCH3), 1.92–1.74 (m, 4H, 2 x CH2), 1.60 (dt, J 15.1, 7.7 Hz, 2H, CH2); 13C NMR (101 MHz, CDCl3) δ: 167.9,
162.3, 161.2, 155.9, 154.1, 151.1, 149.6, 143.4, 134.9, 128.7, 126.5, 126.2, 124.8, 122.8, 121.5, 121.1, 112.9,
112.4, 112.3, 110.1, 101.3, 68.8, 68.4, 56.2, 29.0, 28.9, 25.7; HRMS (ESI) m/z for C28H26NO5S [M+H]+ calcd.
488.1532, found, 488.1523.
7-{6-[4-(Benzothiazol-2-yl)-2-methoxyphenoxy]hexyloxy}-2H-chromen-2-one (6o). Yellow-white powder;
yield 46.5%; mp 125–126 oC; 1H NMR (400 MHz, DMSO-d6) δ: 8.11 (d, J 7.9 Hz, 1H, Benzothiazole-4-H), 8.01 (dd,
J 16.6, 8.8 Hz, 2H, Benzothiazole-7-H, Coumarin-4-H), 7.70–7.56 (m, 3H, Coumarin-5-H, Benzothiazole-5,6-2H),
7.53 (t, J 7.3 Hz, 1H, Benzothiazol-2-phenyl-6-H), 7.43 (t, J 7.5 Hz, 1H, Benzothiazol-2-phenyl-2-H), 7.13 (d, J 8.4
Hz, 1H, Coumarin-8-H), 6.99 (d, J 2.1 Hz, 1H, Coumarin-6-H), 6.95 (dd, J 8.6, 2.3 Hz, 1H, Benzothiazol-2-phenyl-
5-H), 6.28 (d, J 9.5 Hz, 1H, Coumarin-3-H), 4.07 (dq, J 12.2, 6.8 Hz, 4H, 2 x CH2), 3.89 (s, 3H, OCH3), 1.79 (d, J 5.2
Hz, 4H, 2 x CH2), 1.51 (s, 4H, 2 x CH2); 13C NMR (101 MHz, CDCl3) δ: 167.9, 162.5, 162.2, 161.2, 155.8, 154.1,
151.0, 149.6, 143.4, 134.8, 128.7, 126.5, 126.2, 124.8, 122.7, 121.5, 121.1, 112.8, 112.4, 110.1, 101.3, 68.7,
68.3, 56.1, 36.4, 31.4, 28.7, 22.6; HRMS (ESI) m/z for C29H28NO5S [M+H]+ calcd. 502.1688, found, 502.1680.
7-{2-[4-(Benzothiazol-2-yl)-2-methoxyphenoxy]ethoxy}-4-methyl-2H-chromen-2-one (6p). White powder;
yield 68.4%; mp 218–219 oC; 1H NMR (400 MHz, DMSO-d6) δ: 8.12 (d, J 7.9 Hz, 1H, Benzothiazole-4-H), 8.04 (d,
J 8.1 Hz, 1H, Benzothiazole-7-H), 7.74–7.60 (m, 3H, Coumarin-5-H, Benzothiazole-5,6-2H), 7.54 (t, J 7.6 Hz, 1H,
Benzothiazol-2-phenyl-6-H), 7.44 (t, J 7.6 Hz, 1H, Benzothiazol-2-phenyl-2-H), 7.23 (t, J 7.8 Hz, 1H, Coumarin-8-
H), 7.12 (d, J 2.4 Hz, 1H, Coumarin-6-H), 7.05 (dd, J 8.8, 2.4 Hz, 1H, Benzothiazol-2-phenyl-5-H), 6.24 (s, 1H,
Coumarin-3-H), 4.53–4.42 (m, 4H, 2 x CH2), 3.90 (s, 3H, OCH3), 2.42 (s, 3H, CH3); 13C NMR (101 MHz, CDCl3) δ:
167.7, 161.6, 161.2, 155.2, 154.1, 152.5, 150.4, 149.9, 134.9, 127.6, 126.3, 125.5, 125.0, 122.9, 121.5, 120.9,
113.9, 113.5, 112.7, 112.2, 110.4, 101.8, 67.5, 67.0, 56.1, 18.6; HRMS (ESI) m/z for C26H22NO5S [M+H]+ calcd.
460.1219, found, 460.1208.
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7-{3-[4-(Benzothiazol-2-yl)-2-methoxyphenoxy]propoxy}-4-methyl-2H-chromen-2-one (6q). White powder;
yield 60.2%; mp 156–158 oC; 1H NMR (400 MHz, DMSO-d6) δ: 8.11 (d, J 7.9 Hz, 1H, Benzothiazole-4-H), 8.03 (d,
J 8.1 Hz, 1H, Benzothiazole-7-H), 7.71–7.63 (m, 2H, Coumarin-5-H, Benzothiazole-6-H), 7.60 (d, J 7.9 Hz, 1H,
Benzothiazole-5-H), 7.53 (t, J 7.5 Hz, 1H, Benzothiazol-2-phenyl-6-H), 7.43 (t, J 7.5 Hz, 1H, Benzothiazol-2-
phenyl-2-H), 7.18 (d, J 8.4 Hz, 1H, Coumarin-8-H), 7.04–6.97 (m, 2H, Coumarin-6-H, Benzothiazol-2-phenyl-5-H),
6.21 (s, 1H, Coumarin-3-H), 4.32–4.20 (m, 4H, 2 x CH2), 3.91 (s, 3H, OCH3), 2.39 (s, 3H, CH3), 2.30–2.18 (m, 2H,
CH2); 13C NMR (101 MHz, CDCl3) δ: 167.8, 161.8, 161.2, 155.2, 154.1, 152.5, 150.8, 149.7, 134.8, 126.9, 126.2,
125.5, 124.9, 122.8, 121.5, 121.0, 113.6, 112.7, 112.5, 111.9, 110.2, 101.5, 65.3, 64.9, 56.1, 28.9, 18.6; HRMS
(ESI) m/z for C27H24NO5S [M+H]+ calcd. 474.1375, found, 474.1374.
7-{4-[4-(Benzothiazol-2-yl)-2-methoxyphenoxy]butoxy}-4-methyl-2H-chromen-2-one (6r). Off-white powder;
yield 48.7%; mp 123–124 oC; 1H NMR (400 MHz, DMSO-d6) δ: 8.11 (d, J 7.9 Hz, 1H, Benzothiazole-4-H), 8.03 (d,
J 8.2 Hz, 1H, Benzothiazole-7-H), 7.71–7.63 (m, 2H, Coumarin-5-H, Benzothiazole-6-H), 7.61 (d, J 8.2 Hz, 1H,
Benzothiazole-5-H), 7.53 (t, J 7.6 Hz, 1H, Benzothiazol-2-phenyl-6-H), 7.44 (t, J 7.5 Hz, 1H, Benzothiazol-2-
phenyl-2-H), 7.15 (d, J 8.4 Hz, 1H, Coumarin-8-H), 7.05–6.93 (m, 2H, Coumarin-6-H, Benzothiazol-2-phenyl-5-H),
6.21 (s, 1H, Coumarin-3-H), 4.15 (t, J 16.7 Hz, 4H, 2 x CH2), 3.90 (s, 3H, OCH3), 2.40 (s, 3H, CH3), 1.94 (s, 4H, 2 x
CH2); 13C NMR (101 MHz, CDCl3) δ: 167.9, 162.0, 161.3, 155.2, 154.1, 152.6, 150.9, 149.6, 134.9, 126.7, 126.2,
125.5, 124.9, 122.8, 121.5, 121.0, 113.5, 112.6, 112.4, 111.8, 110.1, 101.3, 68.5, 68.1, 56.1, 25.9, 25.7, 18.6;
HRMS (ESI) m/z for C28H26NO5S [M+H]+ calcd. 488.1532, found, 488.1523.
7-{5-[4-(Benzothiazol-2-yl)-2-methoxyphenoxy]pentyloxy}-4-methyl-2H-chromen-2-one (6s). White powder;
yield 56.5%; mp 126–128 oC; 1H NMR (400 MHz, DMSO-d6) δ: 8.11 (d, J 7.9 Hz, 1H, Benzothiazole-4-H), 8.03 (d,
J 8.1 Hz, 1H, Benzothiazole-7-H), 7.73–7.62 (m, 2H, Coumarin-5-H, Benzothiazole-6-H), 7.58 (t, J 10.1 Hz, 1H,
Benzothiazole-5-H), 7.53 (t, J 7.6 Hz, 1H, Benzothiazol-2-phenyl-6-H), 7.43 (t, J 7.6 Hz, 1H, Benzothiazol-2-
phenyl-2-H), 7.13 (d, J 8.3 Hz, 1H, Coumarin-8-H), 6.97 (d, J 13.6 Hz, 2H, Coumarin-6-H, Benzothiazol-2-phenyl-
5-H), 6.20 (s, 1H, Coumarin-3-H), 4.15–4.06 (m, 4H, 2 x CH2), 3.90 (s, 3H, OCH3), 2.38 (s, 3H, CH3), 1.89–1.76 (m,
4H, 2 x CH2), 1.61 (dd, J 14.5, 7.7 Hz, 2H, CH2); 13C NMR (101 MHz, CDCl3) δ: 167.9, 162.0, 161.3, 155.2, 154.1,
152.5, 151.0, 149.6, 134.8, 126.5, 126.2, 125.4, 124.8, 122.8, 121.5, 121.1, 113.4, 112.5, 112.4, 111.8, 110.1,
101.3, 68.7, 68.2, 56.2, 28.7, 28.7, 22.6, 18.6; HRMS (ESI) m/z for C29H28NO5S [M+H]+ calcd. 502.1688, found,
502.1681.
7-{6-[4-(Benzothiazol-2-yl)-2-methoxyphenoxy]hexyloxy}-4-methyl-2H-chromen-2-one (6t). White powder;
yield 54.2%; mp 118–119 oC; 1H NMR (400 MHz, DMSO-d6) δ: 8.11 (d, J 7.9 Hz, 1H, Benzothiazole-4-H), 8.03 (d,
J 8.1 Hz, 1H, Benzothiazole-7-H), 7.70–7.62 (m, 2H, Coumarin-5-H, Benzothiazole-6-H), 7.58 (t, J 9.9 Hz, 1H,
Benzothiazole-5-H), 7.53 (t, J 7.6 Hz, 1H, Benzothiazol-2-phenyl-6-H), 7.43 (t, J 7.6 Hz, 1H, Benzothiazol-2-
phenyl-2-H), 7.12 (d, J 8.4 Hz, 1H, Coumarin-8-H), 6.96 (d, J 9.8 Hz, 2H, Coumarin-6-H, Benzothiazol-2-phenyl-
5-H), 6.20 (s, 1H, Coumarin-3-H), 4.07 (dt, J 18.5, 9.2 Hz, 4H, 2 x CH2), 3.89 (s, 3H, OCH3), 2.38 (s, 3H, CH3), 1.79
(d, J 5.0 Hz, 4H, 2 x CH2), 1.51 (s, 4H, 2 x CH2); 13C NMR (101 MHz, CDCl3) δ: 167.9, 162.1, 161.3, 155.2, 154.1,
152.5, 151.1, 149.6, 134.8, 126.5, 126.2 , 125.4, 124.8, 122.8, 121.5, 121.1, 113.4, 112.6, 112.3, 111.8, 110.1,
101.3, 68.8, 68.3, 56.2, 28.9, 28.9, 25.7, 25.7, 18.6; HRMS (ESI) m/z for C30H30NO5S [M+H]+ calcd. 516.1845,
found, 516.1842.
7-{2-[3-(Benzothiazol-2-yl)phenoxy]ethoxy}-2H-chromen-2-one (6u). White powder; yield 71.2%; mp 183–
o
1
185 C; H NMR (400 MHz, DMSO-d6) δ: 8.17 (d, J 7.8 Hz, 1H, Benzothiazole-4-H), 8.08 (d, J 7.8 Hz, 1H,
Benzothiazole-7-H), 8.00 (t, J 14.0 Hz, 1H, Coumarin-4-H), 7.73–7.63 (m, 3H, Benzothiazol-2-phenyl-6-H,
Coumarin-5-H, Benzothiazole-5-H), 7.61–7.41 (m, 3H, Benzothiazole-6-H, Benzothiazol-2-phenyl-2,5-2H), 7.27–
7.19 (m, 1H, Benzothiazol-2-phenyl-4-H), 7.11 (d, J 2.3 Hz, 1H, Coumarin-8-H), 7.03 (dt, J 12.7, 4.7 Hz, 1H,
Coumarin-6-H), 6.31 (d, J 9.5 Hz, 1H, Coumarin-3-H), 4.50 (s, 4H, 2 x CH2); 13C NMR (101 MHz, CDCl3) δ: 167.6,
161.7, 161.1, 158.9, 155.8, 154.0, 143.3, 135.0, 135.0, 130.2, 128.8, 126.4, 125.3, 123.2, 121.6, 120.8, 118.0,
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113.4, 113.0, 112.9, 112.8, 101.6, 67.0, 66.4; HRMS (ESI) m/z for C24H18NO4S [M+H]+ calcd. 416.0957, found,
416.0949.
7-{3-[3-(Benzothiazol-2-yl)phenoxy]propoxy}-2H-chromen-2-one (6v). White powder; yield 56.2%; mp 176–
o
1
178 C; H NMR (400 MHz, DMSO-d6) δ: 8.15 (d, J 7.9 Hz, 1H, Benzothiazole-4-H), 8.08 (d, J 8.0 Hz, 1H,
Benzothiazole-7-H), 7.99 (d, J 9.5 Hz, 1H, Coumarin-4-H), 7.64 (t, J 7.8 Hz, 3H, Benzothiazol-2-phenyl-6-H,
Coumarin-5-H, Benzothiazole-5-H), 7.56 (t, J 7.5 Hz, 1H, Benzothiazole-6-H), 7.53–7.43 (m, 2H, Benzothiazol-2-
phenyl-2,5-2H), 7.24-7.14 (m, 1H, Benzothiazol-2-phenyl-4-H), 7.09–6.93 (m, 2H, Coumarin-6,8-2H), 6.29 (d, J
9.5 Hz, 1H, Coumarin-3-H), 4.29 (dd, J 14.3, 6.3 Hz, 4H, 2 x CH2), 2.26 (dd, J 12.1, 6.0 Hz, 2H, CH2); 13C NMR (101
MHz, CDCl3) δ: 167.8, 162.0, 161.2, 159.2, 155.8, 154.0, 143.4, 135.0, 134.9, 130.1, 128.7, 126.3, 125.2, 123.2,
121.6, 120.4, 117.7, 113.1, 112.8, 112.6, 101.5, 64.9, 64.3, 29.0; HRMS (ESI) m/z for C25H20NO4S [M+H]+ calcd.
430.1113, found, 430.1112.
7-{4-[3-(Benzothiazol-2-yl)phenoxy]butoxy}-2H-chromen-2-one (6w). White powder; yield 68.7%; mp 123–
o
1
125 C; H NMR (400 MHz, DMSO-d6) δ: 8.15 (t, J 7.0 Hz, 1H, Benzothiazole-4-H), 8.07 (d, J 8.1 Hz, 1H,
Benzothiazole-7-H), 7.99 (d, J 9.5 Hz, 1H, Coumarin-4-H), 7.68–7.59 (m, 3H, Benzothiazol-2-phenyl-6-H,
Coumarin-5-H, Benzothiazole-5-H), 7.56 (t, J 7.6 Hz, 1H, Benzothiazole-6-H), 7.49 (td, J 7.6, 3.9 Hz, 2H,
Benzothiazol-2-phenyl-2,5-2H), 7.17 (d, J 6.0 Hz, 1H, Benzothiazol-2-phenyl-4-H), 7.02 (s, 1H, Coumarin-8-H),
6.97 (d, J 8.6 Hz, 1H, Coumarin-6-H), 6.28 (d, J 9.5 Hz, 1H, Coumarin-3-H), 4.19 (s, 4H, 2 x CH2), 1.97 (d, J 17.6
Hz, 4H, 2 x CH2); 13C NMR (101 MHz, CDCl3) δ: 167.9, 162.2, 161.2, 159.3, 155.9, 154.0, 143.4, 135.0, 134.9,
130.0, 128.7, 126.3, 125.2, 123.2, 121.6, 120.2, 117.6, 113.0, 112.9, 112.7, 112.5, 101.4, 68.1, 67.6, 25.9, 25.8;
HRMS (ESI) m/z for C26H22NO4S [M+H]+ calcd. 444.1270, found, 444.1259.
7-{5-[3-(Benzothiazol-2-yl)phenoxy]butoxy}-2H-chromen-2-one (6x). White powder; yield 47.5%; mp 143–
o
1
145 C; H NMR (400 MHz, DMSO-d6) δ: 8.16 (d, J 7.9 Hz, 1H, Benzothiazole-4-H), 8.08 (d, J 8.1 Hz, 1H,
Benzothiazole-7-H), 7.99 (d, J 9.5 Hz, 1H, Coumarin-4-H), 7.69–7.59 (m, 3H, Benzothiazol-2-phenyl-6-H,
Coumarin-5-H, Benzothiazole-5-H), 7.56 (t, J 7.6 Hz, 1H, Benzothiazole-6-H), 7.49 (dd, J 10.9, 5.0 Hz, 2H,
Benzothiazol-2-phenyl-2,5-2H), 7.16 (d, J 8.2 Hz, 1H, Benzothiazol-2-phenyl-4-H), 7.00 (s, 1H, Coumarin-8-H),
6.96 (d, J 8.6 Hz, 1H, Coumarin-6-H), 6.28 (d, J 9.5 Hz, 1H, Coumarin-3-H), 4.13 (t, J 6.3 Hz, 4H, 2 x CH2), 1.89–
1.78 (m, 4H, 2 x CH2), 1.67–1.57 (m, 2H, CH2); 13C NMR (101 MHz, CDCl3) δ: 168.0, 162.3, 161.2, 159.5, 155.9,
153.9, 143.4, 135.0, 134.8, 130.0, 128.7, 126.3, 125.2, 123.2, 121.6, 120.2, 117.7, 112.9, 112.7, 112.4, 101.3,
68.4, 67.9, 28.9, 28.7, 22.7; HRMS (ESI) m/z for C27H24NO4S [M+H]+ calcd. 458.1426, found, 458.1419.
7-{6-[3-(Benzothiazol-2-yl)phenoxy]hexyloxy}-2H-chromen-2-one (6y). White powder; yield 47.8%; mp 134–
o
1
136 C; H NMR (400 MHz, DMSO-d6) δ: 8.14 (d, J 7.9 Hz, 1H, Benzothiazole-4-H), 8.07 (d, J 8.0 Hz, 1H,
Benzothiazole-7-H), 7.97 (d, J 9.5 Hz, 1H, Coumarin-4-H), 7.59 (ddd, J 21.6, 14.1, 7.7 Hz, 4H, Benzothiazol-2-
phenyl-6-H, Coumarin-5-H, Benzothiazole-5,6-2H), 7.47 (t, J 7.7 Hz, 2H, Benzothiazol-2-phenyl-2,5-2H), 7.15 (d,
J 8.1 Hz, 1H, Benzothiazol-2-phenyl-4-H), 6.98 (s, 1H, Coumarin-8-H), 6.94 (d, J 8.6 Hz, 1H, Coumarin-6-H), 6.27
(d, J 9.5 Hz, 1H, Coumarin-3-H), 4.09 (d, J 5.9 Hz, 4H, 2 x CH2), 1.78 (d, J 5.3 Hz, 4H, 2 x CH2), 1.51 (s, 4H, 2 x
CH2); 13C NMR (101 MHz, CDCl3) δ: 167.9, 162.3, 161.2, 159.5, 155.9, 154.0, 143.4, 135.0, 134.8, 130.0, 128.7,
126.3, 125.2, 123.2, 121.6, 120.1, 117.6, 112.9, 112.7, 112.4, 101.3, 68.4, 67.9, 29.1, 28.9, 25.8, 25.7; HRMS
(ESI) m/z for C28H26NO4S [M+H]+ calcd. 472.1583, found, 472.1574.
7-{2-[3-(Benzothiazol-2-yl)phenoxy]ethoxy}-4-methyl-2H-chromen-2-one (6z). White powder; yield 65.7%;
mp 189–190 oC; 1H NMR (400 MHz, DMSO-d6) δ: 8.17 (dd, J 7.5, 4.5 Hz, 1H, Benzothiazole-4-H), 8.09 (t, J 7.2 Hz,
1H, Benzothiazole-7-H), 7.85–7.61 (m, 3H, Coumarin-5-H, Benzothiazol-2-phenyl-6-H, Benzothiazole-5-H),
7.62–7.43 (m, 3H, Benzothiazole-6-H, Benzothiazol-2-phenyl-2,5-2H), 7.33–7.15 (m, 1H, Benzothiazol-2-
phenyl-4-H), 7.10 (d, J 2.4 Hz, 1H, Coumarin-8-H), 7.07–7.02 (m, 1H, Coumarin-6-H), 6.23 (s, 1H, Coumarin-3-H),
4.59–4.41 (m, 4H, 2 x CH2), 2.41 (s, 3H,CH3); 13C NMR (101 MHz, CDCl3) δ: 167.6, 161.5, 161.2, 158.9, 155.2,
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154.0, 152.5, 135.0, 135.0, 130.2, 126.4, 125.6, 125.3, 123.2, 121.6, 120.8, 118.0, 112.8, 112.7, 112.2, 101.6,
67.0, 66.5, 18.6; HRMS (ESI) m/z for C25H20NO4S [M+H]+ calcd. 430.1113, found, 430.1107.
7-{3-[3-(Benzothiazol-2-yl)phenoxy]propoxy}-4-methyl-2H-chromen-2-one (6aa).White powder; yield 53.5%;
mp 117–119 oC; 1H NMR (400 MHz, DMSO-d6) δ: 8.15 (d, J 8.0 Hz, 1H, Benzothiazole-4-H), 8.08 (d, J 8.1 Hz, 1H,
Benzothiazole-7-H), 7.72–7.60 (m, 3H, Coumarin-5-H, Benzothiazol-2-phenyl-6-H, Benzothiazole-5-H), 7.56 (t, J
7.7 Hz, 1H, Benzothiazole-6-H), 7.52–7.43 (m, 2H, Benzothiazol-2-phenyl-2,5-2H), 7.20 (d, J 9.0 Hz, 1H,
Benzothiazol-2-phenyl-4-H), 7.03 (dd, J 9.9, 5.2 Hz, 2H, Coumarin-6,8-2H), 6.21 (s, 1H, Coumarin-3-H), 4.29 (dd,
J 13.6, 6.5 Hz, 4H, 2 x CH2), 2.39 (s, 3H, CH3), 2.31–2.21 (m, 2H, CH2); 13C NMR (101 MHz, CDCl3) δ: 167.8, 161.8,
161.2, 159.2, 155.2, 153.9, 152.5, 135.0, 134.9, 130.1, 126.3, 125.5, 125.3, 123.2, 121.6, 120.4, 117.8, 113.6,
112.6, 112.5, 112.0, 101.5, 64.9, 64.3, 29.1, 18.6; HRMS (ESI) m/z for C26H22NO4S [M+H]+ calcd. 444.1270,
found, 444.1263.
7-{4-[3-(Benzothiazol-2-yl)phenoxy]butoxy}-4-methyl-2H-chromen-2-one (6bb).White powder; yield 78.3%;
mp 142–144 oC; 1H NMR (400 MHz, DMSO-d6) δ: 8.14 (t, J 6.4 Hz, 1H, Benzothiazole-4-H), 8.07 (d, J 8.0 Hz, 1H,
Benzothiazole-7-H), 7.71–7.61 (m, 2H, Coumarin-5-H, Benzothiazol-2-phenyl-6-H), 7.57 (dd, J 15.3, 7.2 Hz, 2H,
Benzothiazole-5,6-2H), 7.48 (td, J 7.5, 3.8 Hz, 2H, Benzothiazol-2-phenyl-2,5-2H), 7.17 (dd, J 8.2, 1.6 Hz, 1H,
Benzothiazol-2-phenyl-4-H), 6.98 (dd, J 12.8, 4.1 Hz, 2H, Coumarin-6,8-2H), 6.19 (s, 1H, Coumarin-3-H), 4.19 (s,
4H, 2 x CH2), 2.38 (s, 3H,CH3), 1.95 (s, 4H, 2 x CH2); 13C NMR (101 MHz, CDCl3) δ: 167.86, 162.0, 161.3, 159.3,
155.2, 154.0, 152.5, 135.0, 134.8, 130.0, 126.3, 125.5, 125.2, 123.2, 121.6, 120.2, 117.6, 113.5, 112.7, 112.5,
111.8, 101.3, 68.0, 67.6, 25.8, 18.6; HRMS (ESI) m/z for C27H24NO4S [M+H]+ calcd. 458.1426, found, 458.1417.
7-{5-[3-(Benzothiazol-2-yl)phenoxy]pentyloxy}-4-methyl-2H-chromen-2-one (6cc). Yellow powder; yield
44.6%; mp 114–116 oC; 1H NMR (400 MHz, DMSO-d6) δ: 8.14 (d, J 7.8 Hz, 1H, Benzothiazole-4-H), 8.06 (d, J 8.0
Hz, 1H, Benzothiazole-7-H), 7.66–7.52 (m, 4H, Coumarin-5-H, Benzothiazol-2-phenyl-6-H, Benzothiazole-5,6-
2H), 7.47 (t, J 7.8 Hz, 2H, Benzothiazol-2-phenyl-2,5-2H), 7.15 (dd, J 8.2, 2.1 Hz, 1H, Benzothiazol-2-phenyl-4-H),
6.98–6.91 (m, 2H, Coumarin-6,8-2H), 6.19 (t, J 2.9 Hz, 1H, Coumarin-3-H), 4.11 (t, J 5.8 Hz,4H, 2 x CH2), 2.37 (s,
3H,CH3), 1.89–1.78 (m, 4H, 2 x CH2), 1.66–1.50 (m, 2H, CH2); 13C NMR (101 MHz, CDCl3) δ: 167.9, 162.1, 161.3,
159.5, 155.2, 153.9, 152.5, 135.0, 134.8, 130.0, 126.3, 125.5, 125.2, 123.2, 121.6, 120.1, 117.7, 113.4, 112.7,
112.6, 111.8, 101.3, 68.3, 67.9, 28.9, 28.7, 22.7, 18.6; HRMS (ESI) m/z for C28H26NO4S [M+H]+ calcd. 472.1583,
found, 472.1573.
7-{6-[3-(Benzothiazol-2-yl)phenoxy]hexyloxy}-4-methyl-2H-chromen-2-one (6dd). White powder; yield 56.6%;
mp 128–130 oC; 1H NMR (400 MHz, DMSO-d6) δ: 8.15 (d, J 7.8 Hz, 1H, Benzothiazole-4-H), 8.07 (d, J 8.1 Hz, 1H,
Benzothiazole-7-H), 7.70–7.59 (m, 3H, 4H, Coumarin-5-H, Benzothiazol-2-phenyl-6-H, Benzothiazole-5-H), 7.56
(t, J 7.6 Hz, 1H, Benzothiazole-6-H), 7.48 (t, J 7.6 Hz, 2H, Benzothiazol-2-phenyl-2,5-2H), 7.16 (d, J 8.1 Hz, 1H,
Benzothiazol-2-phenyl-4-H), 6.96 (d, J 10.3 Hz, 2H, Coumarin-6,8-2H), 6.20 (s, 1H, Coumarin-3-H), 4.10 (t, J 5.8
Hz, 4H, 2 x CH2), 2.38 (s, 3H,CH3), 1.79 (d, J 4.9 Hz, 4H, 2 x CH2), 1.52 (s, 4H, 2 x CH2); 13C NMR (101 MHz, CDCl3)
δ: 167.9, 162.1, 161.3, 159.5, 155.2, 154.0, 152.6, 135.0, 134.8, 130.0, 126.3, 125.4, 125.2, 123.2, 121.6, 120.0,
117.6, 113.4, 112.7, 112.6, 111.7, 101.3, 68.4, 67.9, 29.1, 28.9, 25.8, 25.7, 18.6; HRMS (ESI) m/z for C29H28NO4S
[M+H]+ calcd. 486.1739, found, 486.1735.
Crystallographic study. The single crystal of 6v was obtained from the mixed liquor of chloroform and
methanol (v/v=1: 1). The X-ray single crystal diffraction data were collected on an Agilent SuperNova (Dual, Cu
at zero, AtlasS2) diffractometer at 100.00(10) K using Mo Kα radiation (λ = 0.71073 Å) by the ω scan mode.
The program CrysAlisPro was used for integration of the diffraction profiles.22 The structure was solved by
direct methods using the SHELXS program of the SHELXTL package and refined by full-matrix least-squares
methods with SHELXL.23 All non-hydrogen atoms of the compound 6v were refined with anisotropic thermal
parameters. All hydrogen atoms were observed and placed at their calculated positions with a fixed value of
their isotropic displacement parameters.
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In vivo insecticidal activity assay. The test insects Plutella xylostella and Aphis fabae were reared at 25 (±1) oC
and 60 (±5)% relative humidity in a greenhouse. The bioactivity of title compounds against P. xylostella and
aphid (A. fabae) were tested according to the modified leaf-dip method using the reported procedure.24,25 The
compounds were dissolved in DMF and then diluted with water (containing 0.1% Triton X-100). The disks of
Chinese cabbage leaves were prepared and dipped in a test solution for 10 s. After drying, the leaves were
placed in a plastic dish with ten third instar larvae (P. xylostella). The mortality was determined after 120 h by
the dead insect number in the treated dishes relative to that in the untreated controls. At the same time,
Horsebean seedlings with apterous adult A. fabae were prepared and dipped in a test solution for 10 s. After
drying, the seedlings were placed in a glass bottle. The mortality was determined after 72 h. All the treatments
and controls were carried out in three replicates.
Acknowledgements
This work was supported by the Fundamental Research Funds for the Central Universities of China (No.
KYTZ201604 and KJSY201607).
Supplementary Material
1
Data of the key intermediates, copies of H and 13C NMR spectra of the new compounds, and crystallographic
data of compound 6v.
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