Efficient synthesis and antiproliferative activity of novel thioether-substituted flavonoids

Article abstract of DOI:10.1016/j.ejmech.2013.05.037

As widely occurring natural products, flavonoids are an important source for drug discovery, due to their structural diversity and broad-spectrum biological activity. In this work, a library of novel, thioethersubstituted flavonoids with diverse heterocyclic groups was synthesized via a microwave-assisted procedure with the advantages of good yields, short times, mild conditions and ready isolation of the products. Their antiproliferative activities were evaluated against six cancer cell lines, HCCLM-7, Hela, MDA-MB-435S, SW-480, Hep-2, and MCF-7 by the MTT-based assay. Compared with the positive control 5-fluorouracil, three compounds, 6a, 6b and 6j were successfully identified as the most promising candidates, due to their higher potency and broad-spectrum bioactivity with IC₅₀ values in the range of 0.43 μM-6.7 μM.

Full text of DOI:10.1016/j.ejmech.2013.05.037

Accepted Manuscript
Efficient Synthesis and Antiproliferative Activity of Novel Thioether-Substituted
Flavonoids
Wei Huang, Qiong Chen, Wen-Chao Yang, Guang-Fu Yang, Ph.D
PII:
S0223-5234(13)00355-3
10.1016/j.ejmech.2013.05.037
EJMECH 6215
DOI:
Reference:
To appear in: European Journal of Medicinal Chemistry
Received Date: 21 February 2013
Revised Date: 24 May 2013
Accepted Date: 25 May 2013
Please cite this article as: W. Huang, Q. Chen, W.-C. Yang, G.-F. Yang, Efficient Synthesis and
Antiproliferative Activity of Novel Thioether-Substituted Flavonoids, European Journal of Medicinal
Chemistry (2013), doi: 10.1016/j.ejmech.2013.05.037.
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to
our customers we are providing this early version of the manuscript. The manuscript will undergo
copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please
note that during the production process errors may be discovered which could affect the content, and all
legal disclaimers that apply to the journal pertain.

ACCEPTED MANUSCRIPT
Efficient Synthesis and Antiproliferative Activity of Novel Thioether-Substituted
Flavonoids
Wei Huang, Qiong Chen, Wen-Chao Yang and Guang-Fu Yang*
A library of 57 novel flavonoids bearing diverse heterocyclic groups were efficiently synthesized via
microwave-assisted procedure. Three candidates with promising potent and broad- spectrum antitumor
activity were successfully identified.

ACCEPTED MANUSCRIPT
Efficient Synthesis and Antiproliferative Activity of Novel
Thioether-Substituted Flavonoids
Wei Huang,1,2 Qiong Chen,1 Wen-Chao Yang1 and Guang-Fu Yang1,*
1Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of
Chemistry, Central China Normal University, Wuhan 430079, P.R. China
2Jiangsu Key Laboratory of Molecular Targeted Antitumor Drug Research, Jiangsu Simcere
Pharmaceutical Co. Ltd, Nanjing 210042, P. R. China
Corresponding author:
Guang-Fu Yang, Ph.D & Professor
Dean of College of Chemistry, Central China Normal University
Director of Key Laboratory of Pesticide & Chemical Biology, Ministry of Education
Wuhan 430079, P. R. China
Tel: +86-27-67867800
Fax: +86-27-67867141
E-mail: gfyang@mail.ccnu.edu.cn

ACCEPTED MANUSCRIPT
Abstract As widely occurring natural products, flavonoids are an important source for drug
discovery, due to their structural diversity and broad-spectrum biological activity. In this work,
a library of novel, thioether-substituted flavonoids with diverse heterocyclic groups were
synthesized via a microwave-assisted procedure with the advantages of good yields, short times,
mild conditions and ready isolation of the products. Their antiproliferative activities were
evaluated against six cancer cell lines, HCCLM-7, Hela, MDA-MB-435S, SW-480, Hep-2, and
MCF-7 by the MTT-based assay. Compared with the positive control 5-fluorouracil, three
compounds, 6a, 6b and 6j were successfully identified as the most promising candidates, due to
their higher potency and broad-spectrum bioactivity with IC50 values in the range of 0.43 ꢀM –
6.7 ꢀM.
Keywords: Flavonoids; Chromone; Thioether; Antiproliferative activity; Microwave-assisted
Synthesis.

ACCEPTED MANUSCRIPT
1. Introduction
Flavonoids occur throughout the plant kingdom; they are one of the most representative
families of plant secondary metabolites. Flavonoids display a remarkable spectrum of biological
activities, and they are used as privileged structures in drug discovery. Most interestingly,
compelling data have indicated that flavonoids have important chemopreventive and
chemotherapeutic effects on cancer. Attention has been focused on their potential anticancer
effect for decades [1-4]. For example, flavopiridol (1), shown in Figure 1, was identified as the
first cyclin-dependent kinase inhibitor, and it is currently being tested in Phase II clinical trials
[5]. On the other hand, many studies have indicated that functional thioether groups can
enhance the antitumor activity of candidate compounds. Noteworthily, the structural
modification of flavonoids, with the introduction of sulfur atoms, has attracted considerable
attention [6-7]. For example, the thio-flavopiridol analogues 2 are more potent and selective
than flavopiridol alone. We also reported previously that thioether-substituted chromones 3 had
weak anti-proliferative activity [8]. More interestingly, the insertion of a CH2 bridge between
the dithiocarboxylate (DTC) moiety and the chromone ring of compound 4 significantly
improved its antiproliferative activity; this indicated that the flexibility of the DTC group might
be a vital factor for the activity of compound 4 [9].
Insert Figure 1 here
Based on the above considerations, we proposed that introducing diverse heterocyclic
groups into the flavonoid scaffold with a flexible, thio-methyl linkage might be an effective
strategy for discovering novel flavonoids with potential bioactivity. Therefore, we synthesized
compounds 5, 6, 7, and 8 (Figure 2) with the aim of discovering a new lead structure with

ACCEPTED MANUSCRIPT
antiproliferative activity. Herein, we described the detailed synthetic routes, screening results,
and structure-activity relationships of these compounds. With this approach, we successfully
identified some 3-substituted chromones with promising, broad-spectrum antiproliferative
activity.
Insert Figure 2 here
2. Results and Discussion
2.1 Chemistry
Insert Scheme 1 here
The synthetic routes for compounds 5-8 are outlined in Scheme 1. To construct a library of
thio-flavones with broad structural diversity, we first synthesized diversified halogenated
intermediates M1-4, according to reported procedures [8-14]. To complete the synthetic
sequence, the remaining step involved the condensation of halogenated flavonoids and
appropriate heterocylic thiols to form the desired compounds. Our recent success in application
of microwave irradiation [8, 15-17] prompted us to synthesize the title compounds under
microwave irradiation. As a model reaction, we chose the reaction between 2-
chloromethylchromone-4-one (M1a) and 5,7-dimethyl[1,2,4]Triazo-
[1,5-a]-pyrimidine-2-thiol (M5a) to optimize the reaction conditions (Scheme 2). By optimizing
the temperature, reaction time, and base, we obtained optimized conditions. M5a reacted with
sodium hydroxide (1.1 equiv) and M1a (1.0 equiv) at 90 °C to afford a good yield of the desired
title compound, 5f. Compared to conventional heating, the microwave-assisted synthetic
method provided many advantages, including higher yields (91% vs. 79%), shorter reaction
times (8 min vs. 120 min), mild conditions, and ready isolation of the products.

ACCEPTED MANUSCRIPT
Insert Scheme 2 here
The structures of all synthesized compounds were characterized by elemental analyses, 1H
NMR, and EI-MS techniques. Six representative compounds were further characterized by 13C
NMR spectrum. In addition, the crystal structure of 5h was determined by X-ray diffraction
analysis [18]. As shown in Figure 3, the crystal structure showed that 5h had a C-shape. The
planes of the benzopyrone and triazopyrimidine were nearly parallel, with a dihedral angle of
8.92°.
Insert Figure 3 here
2.2 Pharmacology
The in vitro anti-proliferative activities of the synthesized compounds 5, 6, 7, and 8 were
tested in six cancer cell lines, including HCCLM-7 (hepatoma carcinoma cells), Hela (cervical
carcinoma cells), MDA-MB-435S (mammary adenocarcinoma cells), SW-480 (colon
carcinoma cells), Hep-2 (laryngocarcinoma cells), and MCF-7 (mammary adenocarcinoma
cells). Cell proliferative activities were assayed with the MTT method [19]. The results,
expressed as IC50, are summarized in Table 1.
Insert Table 1 here
Unfortunately, most of the 2-substituted thio-chromone derivatives of compound 5 were
ineffective (IC50 >25 µM, data not shown). Remarkably, 3-substituted thio-chromone
derivatives of compound 6 displayed substantial antiproliferative activities. As shown in Table
1 and Figure 4, compounds with H1, H2, and H14 side-chains displayed the most promising
antiproliferative activity against a broad spectrum of tumor cell types. For example, the IC50
values of compound 6a and 6j ranged from 0.79 µM to 5.4 µM against all of the tested cell lines.

ACCEPTED MANUSCRIPT
The IC50 values of compound 6b were 0.43 µM, 0.63 µM, and 1.0 µM against HCC-LM7,
MDA-MB-435s, and SW-480 cells, respectively. Furthermore, the side-chains of H3, H6, H11,
and H12 also showed considerable activity. For example, the IC50 values of compounds 6e, 6g,
and 6h ranged from 1.1 µM to 7.1 µM against HCC-LM7, MDA-MB-435s, SW-480, and Hep-
2 cells. The IC50 values of compound 6c were 0.73 µM, 0.95 µM, and 1.5 µM against HCC-
LM7, MDA-MB-435s, and Hep-2 cells, respectively. However, the introduction of a Cl atom
onto the 6-position did not improve the activity (e.g., 6a vs. 6k & 6b vs. 6l). Most interestingly,
three potent compounds 6a, 6b & 6j displayed significantly higher activity than 5-fluorouracil
(5-FU) against HCCLM-7 (6.6-43.3 fold), MDA-MB-435S (8.3-23.3 fold), SW-480 (2.3-10.3
fold) and Hep-2 (33.9-91.9 fold), while they showed comparabler activity than 5-FU against
Hela (0.7-1.3 fold) and MCF-7 (0.5-0.8 fold).
Insert Figure 4 here
In addition, after removing the CH2 bridge between the thioether moiety and the chromone
ring of compound 6, the antiproliferative activities of compounds 6m-n were significantly
reduced. This indicated that the flexibility of the thioether group might be a vital factor for
maintaining the activity. Similarly, when the thioether moiety was moved onto position-4 of
coumarine ring, the antiproliferative activities of the resulting derivatives of compound 7 were
also significantly reduced. Because thio-quinazoline is an isoster of chromone, we speculated
that it should show potent activity. Unexpectedly, only 8f with the thio-chromone moiety
displayed considerable activity, with IC50 values of 4.1-17.0 µM; this was comparable to its
corresponding chromone derivative, 6j.
Insert Figure 5 here

ACCEPTED MANUSCRIPT
To study the effects of the synthesized compounds on cell cycle progression, we
performed flow cytometry analysis [20]. The most promising compound, 6b, was tested against
SW-480 cell lines at three different concentrations, with the MTT assay. Figure 5 and Table 2
show the results after cells were treated with 6b for 48 h. Compound 6b arrested the SW-480
cell cycle in G2/M phase with a concentration-dependent effect. The G2/M peak increased from
13.99% to 22.03% (0.8 µM 6b), 26.74% (1.0 µM 6b), and 38.03% (1.2 µM 6b) after 48 h of
treatment.
Insert Table 2 here
3. Conclusion
In conclusion, the present work described the efficient microwave-assisted synthesis of a
library of novel, thioether-substituted flavonoids, with diverse heterocyclic groups. Based on
the result of the MTT assay, we found that the most promising candidates were three 3-
substituted thio-chromone derivatives, 3-((5-methyl-1,3,4-oxadiazol-2-ylthio)methyl)-4H-
chromen-4-one (6a), 3-((5-methyl-1,3,4-thiadiazol-2-ylthio)methyl)-4H-chromen-4-one (6b),
and 3-((4-oxo-4H-thiochromen-2-ylthio)-methyl)-4H-chromen-4-one (6j). Furthermore, flow
cytometry analysis revealed that compound 6b arrested the cell cycle of SW-480 cells in the
G2/M phase with a concentration-dependent effect. On the basis of our results, we concluded
that the introduction of heterocyclic groups into the chromone scaffold with a flexible
thiomethyl linkage was an effective strategy for the future development of flavonoids as novel
anticancer drugs.
4. Experimental protocol
4.1. Chemistry

ACCEPTED MANUSCRIPT
4.1.1. General methods. 1H NMR spectra were recorded at 400 MHz, in CDCl3 or
DMSO-d6 solution on a Mercury-Plus400 spectrometer. 13C NMR spectra were recorded at 100
MHz, in CDCl3 or DMSO-d6 solution on a Mercury-Plus400 spectrometer. Chemical shifts
were recorded in parts per million (ppm), with TMS as the internal reference. MS spectra were
determined with a Tracems2000 organic mass spectrometer, and signals were given in m/z.
Melting points were measured on a Buchi B-545 melting point apparatus. Element analyses
(EA) were measured on a Vario ELIII CHNSO elemental analyzer. All commercially available
solvents and reagents were used as supplied by Acros Organics, unless otherwise stated. The
silica gel (200-300 mesh) for flash column chromatography was purchased from Qingdao
Marine Chemical Factory in China.
4.1.2. General procedure for synthesis of compounds 5-8. The intermediates M1-4 were
synthesized according to previously reported methods [8-9]. A solution of thiol (1 mmol) was
prepared in 1% aqueous NaOH (5 mL). Then, we added, dropwise, 1 mL of halonated-methyl
flavonoids, M1-4 (1 mmol), in DMF. The mixture was heated to 90 °C in an oil bath;
alternatively it was sealed, and then irradiated in a Smith Creator® microwave at 50 100 W to
90 °C. After completion of the reaction, the mixture was diluted with water (40 mL) and the
precipitate was filtered. Finally, the precipitate was recrystallized from an appropriate solvent to
give the title compounds, 5-8.
4.1.3. 2-((5-methyl-1,3,4-oxadiazol-2-ylthio)methyl)-4H-chromen-4-one (5a). Yield:
1
78%; Mp 104- 106 °C; H NMR (400 MHz, CDCl3) δ 2.53 (s, 3 H, CH3), 4.37 (s, 2 H, CH2),
6.50 (s, 1 H, 3-CH), 7.37-7.43 (m, 2 H, ArH), 7.67 (t, J = 8.0 Hz, 2 H, ArH), 8.14 (d, J = 8.0

ACCEPTED MANUSCRIPT
Hz,1 H, ArH); Ms (m/z) 275 (M++1); Anal. calcd for C13H10N2O3S: C, 56.92; H, 3.67; N,
10.21. Found: C, 57.22; H, 3.61; N, 9.99.
4.1.4. 2-((5-methyl-1,3,4-thiadiazol-2-ylthio)methyl)-4H-chromen-4-one (5b). Yield:
1
87%; Mp 180 -181 °C; H NMR (400 MHz, CDCl3) δ 2.74 (s, 3 H, CH3), 4.47 (s, 2 H, CH2),
6.47 (s, 1 H, 3-CH), 7.38-7.44 (m, 2 H, ArH), 7.67 (t, J = 8.0 Hz, 2 H, ArH), 8.17 (d, J = 8.0
Hz,1 H, ArH); Ms (m/z) 290 (M+); Anal. calcd for C13H10N2O2S2: C, 53.77; H, 3.47; N, 9.65.
Found: C, 53.97; H, 3.41; N, 9.42.
4.1.5. 2-((5-amino-1,3,4-thiadiazol-2-ylthio)methyl)-4H-chromen-4-one (5c). Yield:
91%; Mp 230- 231 °C; 1H NMR (400 MHz, DMSO-d6) δ 4.32 (s, 2 H, CH2), 6.14 (s, 1 H, NH2),
6.31 (s, 1 H, 3-CH), 7.45 (t, J = 8.0 Hz,1 H, ArH), 7.58 (d, J = 8.0 Hz, 1 H, ArH), 7.77 (t, J =
8.0 Hz,1 H, ArH), 7.99(d, J = 8.0 Hz, 1 H, ArH); Ms (m/z) 292 (M+); Anal. calcd for
C12H9N3O2S2: C, 49.47; H, 3.11; N, 14.42. Found: C, 49.67; H, 2.99; N, 14.56.
4.1.6. 2-((benzo[d]thiazol-2-ylthio)methyl)-4H-chromen-4-one (5d). Yield: 94%; Mp
116-118; 1H NMR (400 MHz, CDCl3) δ 4.55 (s, 2 H, CH2), 6.55 (s, 1 H, 3-CH), 7.31-7.46 (m, 3
H, ArH), 7.66 (t, J = 8.0 Hz,1 H, ArH), 7.76 (d, J = 8.0 Hz, 1 H, ArH), 7.90 (d, J = 8.0 Hz, 1 H,
ArH), 8.15 (d, J = 8.0 Hz, 1 H, ArH); Ms (m/z) 325(M+); Anal. calcd for C17H11NO2S2: C,
62.75; H, 3.41; N, 4.30. Found: C, 62.89; H, 3.25; N, 4.04.
4.1.7. 2-((4,6-dimethylpyrimidin-2-ylthio)methyl)-4H-chromen-4-one (5e). Yield: 94%;
Mp 182-184 °C; 1H NMR (400 MHz, CDCl3) δ 2.42 (s, 6 H, CH3), 4.34 (s, 2 H, CH2), 6.53 (s, 1
H, 3-CH), 6.74 (s, 1 H, Het-ArH), 7.28 (t, J = 8.0 Hz,1 H, ArH), 7.45(d, J = 8.0 Hz, 1 H, ArH),
7.65 (t, J = 8.0 Hz,1 H, ArH), 8.16(d, J = 8.0 Hz, 1 H, ArH); Ms (m/z) 298 (M+); Anal. calcd for
C16H14N2O2S: C, 64.41; H, 4.73; N, 9.39. Found: C, 64.42; H, 4.61; N, 9.24.

ACCEPTED MANUSCRIPT
4.1.8. 2-((5,7-dimethyl-[1,2,4]triazolo[1,5-a]pyrimidin-2-ylthio)methyl)-4H-chromen-
4-one (5f). Yield: 91%; Mp 200-201 °C; 1H NMR (400 MHz, CDCl3) δ 2.65 (s, 3 H, CH3), 2.74
(s, 3 H, CH3), 4.47 (s, 2 H, CH2), 6.45 (s, 1 H, 3-CH), 6.79 (s, 1 H, Het-ArH), 7.28 (t, J = 8.0
Hz,1 H, ArH), 7.38(d, J = 8.0 Hz, 1 H, ArH), 7.65 (t, J = 8.0 Hz,1 H, ArH), 8.14(d, J = 8.0 Hz,
1 H, ArH); Ms (m/z) 338(M+); Anal. calcd for C17H14N4O2S: C, 60.34; H, 4.17; N, 16.56.
Found: C, 60.05; H, 4.15; N, 16.41.
4.1.9.
2-((5-((5,7-dimethyl-[1,2,4]triazolo[1,5-a]pyrimidin-2-ylthio)methyl)-1,3,4-
1
oxadiazol-2-ylthio)methyl)-4H-chromen-4-one (5g). Yield: 89%; Mp 158-160 °C; H NMR
(400 MHz, CDCl3) δ 2.62 (s, 3 H, CH3), 2.71 (s, 3 H, CH3), 4.35 (s, 2 H, CH2), 4.72 (s, 2 H,
CH2),6.44 (s, 1 H, 3-CH), 6.75 (s, 1 H, Het-ArH), 7.38-7.40 (m, 2 H, ArH), 7.65 (t, J = 7.2 Hz,1
H, ArH), 8.13 (d, J = 8.4 Hz, 1 H, ArH); 13C-NMR (100 MHz, CDCl3) δ 16.9, 24.8, 24.9, 34.2,
110.3, 111.5, 117.9, 123.7, 125.3, 125.7, 133.9, 146.0, 155.7, 156.3, 162.0, 163.1, 164.6, 164.8,
165.4, 177.7; Ms (m/z) 452 (M+); Anal. calcd for C20H16N6O3S2: C, 53.08; H, 3.56; N, 18.57.
Found: C, 53.24; H, 3.55; N, 18.78.
4.1.10.
2-((5-((5,7-dimethyl-[1,2,4]triazolo[1,5-a]pyrimidin-2-ylthio)methyl)-1,3,4-
1
thiadiazol-2-ylthio)methyl)-4H-chromen-4-one (5h). Yield: 90%; Mp 159-160 °C; H NMR
(400 MHz, DMSO-d6) δ 2.64 (s, 3 H, CH3), 2.71 (s, 3 H, CH3), 4.35 (s, 2 H, CH2), 4.72 (s, 2 H,
CH2), 6.45 (s, 1 H, 3-CH), 6.75 (s, 1 H, Het-ArH), 7.36-7.41 (m, 2 H, ArH), 7.65 (t, J = 8.0
Hz,1 H, ArH), 8.13 (d, J = 8.0 Hz, 1 H, ArH); Ms (m/z) 468 (M+); Anal. calcd for
C20H16N6O2S3: C, 51.26; H, 3.44; N, 17.94. Found: C, 51.14; H, 3.38; N, 17.61.
4.1.11. 2-((4-amino-5-((5,7-dimethyl-[1,2,4]triazolo[1,5-a]pyrimidin-2-ylthio)methyl)-
1
4H-1,2,4-triazol-3-ylthio)-methyl)-4H-chromen-4-one (5i). Yield: 91%; Mp 197-198 °C; H

ACCEPTED MANUSCRIPT
NMR (400 MHz, DMSO-d6) δ 2.53 (s, 3 H, CH3), 2.64 (s, 3 H, CH3), 4.43 (s, 2 H, CH2), 4.62
(s, 2 H, CH2),6.23 (s, 1 H, 3-CH), 6.35 (s, 1 H, Het-ArH), 7.10 (s, 1 H, Het-ArH), 7.43-7.49 (m,
2 H, ArH), 7.75 (t, J = 8.0 Hz,1 H, ArH), 7.95 (d, J = 8.40 Hz, 1 H, ArH), 8.32 (s, 2 H, NH2);
13C-NMR (100 MHz, DMSO-d6) δ 16.3, 23.2, 24.3, 32.8, 110.2, 110.5, 118.0, 122.9, 124.7,
125.4, 134.2, 146.2, 149.9, 153.5, 154.9, 155.7, 164.4, 164.5, 164.6, 176.6; Ms (m/z) 466 (M+);
Anal. calcd for C20H18N8O2S2: C, 51.49; H, 3.89; N, 24.02. Found: C, 51.34; H, 3.62; N, 24.03.
4.1.12. 2-((5-((5,7-dimethyl-[1,2,4]triazolo[1,5-a]pyrimidin-2-ylthio)methyl)-4-phenyl-
1
4H-1,2,4-triazol-3-ylthio)methyl)-4H-chromen-4-one (5j). Yield: 87%; Mp 159-160 °C; H
NMR (400 MHz, CDCl3) δ 2.59 (s, 3 H, CH3), 2.66 (s, 3 H, CH3), 4.37 (s, 2 H, CH2), 4.61 (s, 2
H, CH2), 6.42 (s, 1 H, 3-CH), 6.72 (s, 1 H, Het-ArH), 7.28-7.40 (m, 7 H, ArH), 7.64 (t, J = 8.0
Hz,1 H, ArH), 8.14 (d, J = 8.0 Hz, 1 H, ArH); Ms (m/z) 527 (M+); Anal. calcd for
C26H21N7O2S2: C, 59.19; H, 4.01; N, 18.58. Found: C, 58.99; H, 4.02; N, 18.28.
4.1.13.
6-methyl-2-((5-methyl-1,3,4-oxadiazol-2-ylthio)methyl)-4H-chromen-4-one
(5k). Yield: 82%; Mp 131-132 °C; 1H NMR (400 MHz, CDCl3) δ 2.44 (s, 3 H, CH3), 2.53 (s, 3
H, CH3), 4.35 (s, 2 H, CH2), 6.47 (s, 1 H, 3-CH), 7.33 (d, J = 8.0 Hz, 1 H, ArH), 7.48 (d, J = 8.0
Hz, 1 H, ArH), 7.95 (s, 1 H, ArH); Ms (m/z) 289 (M++1); Anal. calcd for C14H12N2O3S: C,
58.32; H, 4.20; N, 9.72. Found: C, 58.58; H, 4.18; N, 9.41.
4.1.14.
6-methyl-2-((5-methyl-1,3,4-thiadiazol-2-ylthio)methyl)-4H-chromen-4-one
1
(5l). Yield: 86%; Mp 195-197 °C; H NMR (400 MHz, CDCl3) δ 2.44 (s, 3 H, CH3), 2.74 (s, 3
H, CH3), 4.46 (s, 2 H, CH2), 6.44 (s, 1 H, 3-CH), 7.33 (d, J = 8.0 Hz, 1 H, ArH), 7.47 (d, J = 8.0
Hz, 1 H, ArH), 7.95 (s, 1 H, ArH); Ms (m/z) 304 (M+); Anal. calcd for C14H12N2O2S2: C, 55.24;
H, 3.97; N, 9.20. Found: C, 55.15 H, 3.95; N, 8.83.

ACCEPTED MANUSCRIPT
4.1.15.
2-((5-amino-1,3,4-thiadiazol-2-ylthio)methyl)-6-methyl-4H-chromen-4-one
(5m). Yield: 92%; Mp 245-247 °C; 1H NMR (400 MHz, DMSO-d6) δ 2.42 (s, 3 H, CH3), 4.30
(s, 2 H, CH2), 6.28 (s, 1 H, 3-CH), 7.49 (d, J = 8.0 Hz, 1 H, ArH), 7.62 (d, J = 8.0 Hz, 1 H,
ArH), 7.80 (s, 1 H, ArH); Ms (m/z) 305 (M+); Anal. calcd for C13H11N3O2S2: C, 51.13; H, 3.63;
N, 13.76. Found: C, 51.39; H, 3.60; N, 13.61.
4.1.16. 2-((benzo[d]thiazol-2-ylthio)methyl)-6-methyl-4H-chromen-4-one (5n). Yield:
1
88%; Mp 133-135 °C; H NMR (400 MHz, CDCl3) δ 2.44 (s, 3 H, CH3), 4.55 (s, 2 H, CH2),
6.54 (s, 1 H, 3-CH), 7.27-7.35 (m, 2 H, ArH), 7.44-7.47 (m, 2 H, ArH), 7.77 (d, J = 8.0 Hz, 1
H, ArH), 7.91 (d, J = 8.0 Hz, 1 H, ArH), 7.95 (s, 1 H, ArH); Ms (m/z) 340 (M+); Anal. calcd for
C18H13NO2S2: C, 63.69; H, 3.86; N, 4.13. Found: C, 63.62; H, 3.806; N, 4.12.
4.1.17. 2-((4,6-dimethylpyrimidin-2-ylthio)methyl)-6-methyl-4H-chromen-4-one (5o).
1
Yield: 91%; Mp 195-196 °C; H NMR (400 MHz, CDCl3) δ 2.42 (s, 6 H, CH3), 2.44 (s, 3 H,
CH3), 4.34 (s, 2 H, CH2), 6.50 (s, 1 H, 3-CH), 6.74 (s, 1 H, Het-ArH), 7.35(d, J = 8.0 Hz, 1 H,
ArH), 7.46 (d, J = 8.0 Hz,1 H, ArH), 7.94 (s, 1 H, ArH); Ms (m/z) 312 (M+); Anal. calcd for
C17H16N2O2S: C, 65.36; H, 5.16; N, 8.97. Found: C, 65.08; H, 5.00; N, 8.80.
4.1.18. 2-((5,7-dimethyl-[1,2,4]triazolo[1,5-a]pyrimidin-2-ylthio)methyl)-6-methyl -
1
4H-chromen-4-one (5p). Yield: 90%; Mp 180-182 °C; H NMR (400 MHz, CDCl3) δ 2.46 (s,
3 H, CH3), 2.64 (s, 3 H, CH3), 2.73 (s, 3 H, CH3), 4.45 (s, 2 H, CH2), 4.86 (s, 2 H, CH2), 6.53 (s,
1 H, 3-CH), 6.76 (s, 1 H, Het-ArH), 7.35 (d, J = 8.0 Hz,1 H, ArH), 7.46 (d, J = 8.0 Hz, 1 H,
ArH), 7.92 (s, 1 H, ArH); Ms (m/z) 352(M+); Anal. calcd for C18H16N4O2S: C, 61.35; H, 4.58;
N, 15.90. Found: C, 60.07; H, 4.46; N, 15.72.

ACCEPTED MANUSCRIPT
4.1.19. 6-chloro-2-((5-methyl-1,3,4-oxadiazol-2-ylthio)methyl)-4H-chromen-4-one (5q).
1
Yield: 84%; Mp 134-135 °C; H NMR (400 MHz, CDCl3) δ 2.52 (s, 3 H, CH3), 4.36 (s, 2 H,
CH2), 6.51 (s, 1 H, 3-CH), 7.39 (d, J = 8.0 Hz, 1 H, ArH), 7.61 (d, J = 8.0 Hz, 1 H, ArH), 8.13
(s, 1 H, ArH); Ms (m/z) 308 (M+); A Anal. calcd for C13H9ClN2O3S: C, 50.57; H, 2.94; N, 9.07.
Found: C, 50.77; H, 2.69; N, 8.86.
4.1.20.
6-chloro-2-((5-methyl-1,3,4-thiadiazol-2-ylthio)methyl)-4H-chromen-4-one
(5r). Yield: 90%; Mp 190 -191 °C; 1H NMR (400 MHz, CDCl3) δ 2.74 (s, 3 H, CH3), 4.47 (s, 2
H, CH2), 6.49 (s, 1 H, 3-CH), 7.38 (d, J = 8.0 Hz, 1 H, ArH), 7.60 (d, J = 8.0 Hz, 1 H, ArH),
8.13 (s, 1 H, ArH); Ms (m/z) 324 (M+); Anal. calcd for C13H9ClN2O2S2: C, 48.07; H, 2.79; N,
8.62. Found: C, 48.27; H, 2.96; N, 8.39.
4.1.21. 2-((5-amino-1,3,4-thiadiazol-2-ylthio)methyl)-6-chloro-4H-chromen-4-one (5s).
1
Yield: 88%; Mp 241-243 °C; H NMR (400 MHz, DMSO-d6) δ 4.32 (s, 2 H, CH2), 6.37 (s, 1
H, 3-CH), 7.66 (d, J = 8.0 Hz, 1 H, ArH), 7.86 (d, J = 8.0 Hz, 1 H, ArH), 7.95 (s, 1 H, ArH);
Ms (m/z) 325 (M+); Anal. calcd for C12H8ClN3O2S2: C, 44.24; H, 2.48; N, 12.90. Found: C,
44.01; H, 2.25; N, 12.72.
4.1.22. 2-((benzo[d]thiazol-2-ylthio)methyl)-6-chloro-4H-chromen-4-one (5t). Yield:
1
83%; Mp 125-127 °C; H NMR (400 MHz, CDCl3) δ 4.55 (s, 2 H, CH2), 6.56 (s, 1 H, 3-CH),
7.32 (t, J = 8.0 Hz, 1 H, ArH), 7.39 (d, J = 8.0 Hz, 1 H, ArH), 7.45 (t, J = 8.0 Hz, 1 H, ArH),
7.59 (d, J = 8.0 Hz, 1 H, ArH), 7.77 (d, J = 8.0 Hz, 1 H, ArH), 7.89 (d, J = 8.0 Hz, 1 H, ArH),
8.12 (s, 1 H, ArH); Ms (m/z) 360 (M+); Anal. calcd for C17H10ClNO2S2: C, 56.74; H, 2.80; N,
3.89. Found: C, 56.63; H, 2.59; N, 3.80.

ACCEPTED MANUSCRIPT
4.1.23. 6-chloro-2-((4,6-dimethylpyrimidin-2-ylthio)methyl)-4H-chromen-4-one (5u).
1
Yield: 91%; Mp 180-182 °C; H NMR (400 MHz, CDCl3) δ 2.42 (s, 6 H, CH3), 4.43 (s, 2 H,
CH2), 6.53 (s, 1 H, 3-CH), 6.75 (s, 1 H, Het-ArH), 7.41 (d, J = 8.0 Hz, 1 H, ArH), 7.59 (d, J =
8.0 Hz,1 H, ArH), 8.12 (s, 1 H, ArH); Ms (m/z) 332 (M+); Anal. calcd for C16H13ClN2O2S: C,
57.74; H, 3.94; N, 8.42. Found: C, 57.45; H, 3.72; N, 8.14.
4.1.24. 6-chloro-2-((5,7-dimethyl-[1,2,4]triazolo[1,5-a]pyrimidin-2-ylthio)methyl)-4H-
chromen-4-one (5v). Yield: 90%; Mp 205-206 °C; 1H NMR (400 MHz, CDCl3) δ 2.64 (s, 6 H,
CH3), 2.73 (s, 3 H, CH3), 4.45 (s, 2 H, CH2), 6.57 (s, 1 H, 3-CH), 6.77 (s, 1 H, Het-ArH), 7.41
(d, J = 8.0 Hz, 1 H, ArH), 7.61 (d, J = 8.0 Hz,1 H, ArH), 8.10 (s, 1 H, ArH); Ms (m/z) 372(M+);
Anal. calcd for C17H13ClN4O2S: C, 54.77; H, 3.51; N, 15.03. Found: C, 54.71; H, 3.25; N, 15.13.
4.1.25. 3-((5-methyl-1,3,4-oxadiazol-2-ylthio)methyl)-4H-chromen-4-one (6a). Yield:
1
83%; Mp 112-114 °C; H NMR (400 MHz, CDCl3) δ 2.49 (s, 3 H, CH3), 4.27 (s, 2 H, CH2),
7.41-7.52 (m, 2 H, ArH), 7.67 (t, J = 8.0 Hz, 1 H, ArH), 8.24 (d, J = 8.0 Hz, 1 H, ArH), 8.40 (s,
1 H, 3-CH); 13C-NMR (100 MHz, CDCl3) δ 11.0, 27.2, 118.3, 120.0, 123.9, 125.3, 125.9, 133.8,
154.9, 156,7, 164.7, 164.9, 176.6; Ms (m/z) 274 (M+); Anal. calcd for C13H10N2O3S: C, 56.92;
H, 3.67; N, 10.21. Found: C, 57.10; H, 3.58; N, 10.04.
4.1.26. 3-((5-methyl-1,3,4-thiadiazol-2-ylthio)methyl)-4H-chromen-4-one (6b). Yield:
1
85%; Mp 168 -170 °C; H NMR (400 MHz, CDCl3) δ 2.71 (s, 3 H, CH3), 4.39 (s, 2 H, CH2),
7.38-7.47 (m, 2 H, ArH), 7.65 (t, J = 7.2 Hz, 1 H, ArH), 8.243 (d, J = 7.2 Hz, 1 H, ArH), 8.38 (s,
1 H, 2-CH); Ms (m/z) 290 (M+); Anal. calcd for C13H10N2O2S2: C, 53.77; H, 3.47; N, 9.65.
Found: C, 53.86; H, 3.30; N, 9.51.
4.1.27. 3-((5-amino-1,3,4-thiadiazol-2-ylthio)methyl)-4H-chromen-4-one (6c). Yield:

ACCEPTED MANUSCRIPT
89%; Mp 201-203 °C; 1H NMR (400 MHz, DMSO-d6) δ 4.31 (s, 2 H, CH2), 7.35-7.42 (m, 2 H,
ArH), 7.63 (t, J = 8.0 Hz, 1 H, ArH), 8.20 (d, J = 8.0 Hz,1 H, ArH), 8.31 (s, 1 H, 2-CH); Ms
(m/z) 291 (M+); Anal. calcd for C12H9N3O2S2: C, 49.47; H, 3.11; N, 14.42. Found: C, 49.60; H,
2.98; N, 14.56.
4.1.28. 3-((5-amino-1H-1,2,4-triazol-3-ylthio)methyl)-4H-chromen-4-one (6d). Yield:
1
82%; Mp 186-188 °C; H NMR (400 MHz, CDCl3) δ 4.86 (s, 2 H, CH2)䟍6.45 (s, 1 H, NH),
7.35-7.42 (m, 2 H, ArH), 7.66 (t, J = 8.0 Hz, 1 H, ArH), 8.01 (d, J = 8.0 Hz, 1 H, ArH), 8.30 (s,
1 H, 2-CH); Ms (m/z) 274(M+); Anal. calcd for C12H10N4O2S: C, 52.54; H, 3.67; N, 20.43.
Found: 52.43; H, 3.89; N, 20.40.
4.1.29. 3-((benzo[d]oxazol-2-ylthio)methyl)-4H-chromen-4-one (6e). Yield: 86%; Mp
1
146-148 °C; H NMR (400 MHz, CDCl3) δ 4.36 (s, 2 H, CH2), 7.23-7.29 (m, 2 H, ArH), 7.38-
7.43 (m, 3 H, ArH), 7.62-7.66 (m, 2 H, ArH), 8.25 (d, J = 8.0 Hz, 1 H, ArH), 8.47 (s, 1 H, 2-
CH); 13C-NMR (100 MHz, CDCl3) δ 27.2, 110.0, 118.2, 118.4, 120.5, 123.9, 124.3, 125.3,
125.9, 133.8, 141.8, 151.7, 154.6, 156,6, 165.3, 176.5; Ms (m/z) 309 (M+); Anal. calcd for
C17H11NO3S: C, 66.01; H, 3.58; N, 4.53. Found: C, 65.89; H, 3.75; N, 4.64.
4.1.30. 3-((4,6-dimethylpyrimidin-2-ylthio)methyl)-4H-chromen-4-one (6f). Yield: 90%;
Mp 176-178 °C; 1H NMR (400 MHz, CDCl3) δ 2.42 (s, 6 H, CH3), 4.25 (s, 2 H, CH2), 6.71 (s, 1
H, 3-CH), 7.37-7.42 (m, 2 H, ArH), 7.64 (t, J = 8.0 Hz, 1 H, ArH), 8.24 (d, J = 8.0 Hz,1 H,
ArH), 8.29 (s, 1 H, 2-CH); Ms (m/z) 298 (M+); Anal. calcd for C16H14N2O2S: C, 64.41; H, 4.73;
N, 9.39. Found: C, 64.33; H, 4.60; N, 9.31.
4.1.31. 3-((5-((5,7-dimethyl-[1,2,4]triazolo[1,5-a]pyrimidin-2-ylthio)methyl)-1,3, 4-
1
thiadiazol-2-ylthio)methyl)-4H-chromen-4-one (6g). Yield: 89%; Mp 171-173 °C; H NMR

ACCEPTED MANUSCRIPT
(400 MHz, DMSO-d6) δ 2.64 (s, 3 H, CH3), 2.72 (s, 3 H, CH3), 4.37 (s, 2 H, CH2), 4.84 (s, 2 H,
CH2), 6.77 (s, 1 H, Het-ArH), 7.36-7.44 (m, 2 H, ArH), 7.64 (t, J = 8.0 Hz, 1 H, ArH), 8.21 (d, J
= 8.0 Hz, 1 H, ArH) , 8.37 (s, 1 H, 2-CH); Ms (m/z) 468 (M+); Anal. calcd for C20H16N6O2S3: C,
51.26; H, 3.44; N, 17.94. Found: C, 51.10; H, 3.41; N, 17.82.
4.1.32. 3-((4-amino-5-((5,7-dimethyl-[1,2,4]triazolo[1,5-a]pyrimidin-2-ylthio) methyl)-
1
4H-1,2,4-triazol-3-ylthio)-methyl)-4H-chromen-4-one (6h). Yield: 81%; Mp 202-204 °C; H
NMR (400 MHz, CDCl3) δ 2.61 (s, 3 H, CH3), 2.70 (s, 3 H, CH3), 4.26 (s, 2 H, CH2), 4.63 (s, 2
H, CH2), 6.73 (s, 1 H, Het-ArH), 7.36-7.42 (m, 2 H, ArH), 7.62 (t, J = 8.0 Hz, 1 H, ArH), 8.18
(d, J = 8.0 Hz, 1 H, ArH) , 8.40 (s, 1 H, 2-CH); Ms (m/z) 466 (M+); Anal. calcd for
C20H18N8O2S2: C, 51.49; H, 3.89; N, 24.02. Found: C, 51.40; H, 3.69; N, 24.11.
4.1.33. 3-((5-((5,7-dimethyl-[1,2,4]triazolo[1,5-a]pyrimidin-2-ylthio)methyl)-4-phenyl-
1
4H-1,2,4-triazol-3-ylthio)methyl)-4H-chromen-4-one (6i). Yield: 79%; Mp 171-173 °C; H
NMR (400 MHz, CDCl3) δ 2.61 (s, 3 H, CH3), 2.66 (s, 3 H, CH3), 4.28 (s, 2 H, CH2), 4.57 (s, 2
H, CH2), 6.71 (s, 1 H, Het-ArH), 7.24 (t, J = 8.0 Hz, 2 H, ArH), 7.32-7.38 (m, 4 H, ArH), 7.43
(d, J = 8.0 Hz,1 H, ArH), 7.66 (t, J = 8.0 Hz, 1 H, ArH), 8.18 (d, J = 8.0 Hz, 1 H, ArH) , 8.50 (s,
1 H, 2-CH);; Ms (m/z) 527 (M+); Anal. calcd for C26H21N7O2S2: C, 59.19; H, 4.01; N, 18.58.
Found: C, 59.02; H, 4.13; N, 18.42.
4.1.34. 3-((4-oxo-4H-thiochromen-2-ylthio)methyl)-4H-chromen-4-one (6j). Yield:
1
86%; Mp 151-153 °C; H NMR (400 MHz, CDCl3) δ 4.22 (s, 2 H, CH2), 7.45 (d, J = 8.0 Hz,1
H, ArH), 7.51-7.62 (m, 4 H, ArH), 7.96 (t, J = 8.0 Hz,1 H, ArH), 8.14 (s,1 H, ArH), 8.29 (d, J =
8.0 Hz,1 H, ArH), 8.46-8.51 (m, 2 H, ArH),; Ms (m/z) 352 (M+); Anal. calcd for C19H12O3S2: C,
64.75; H, 3.43;. Found: C, 64.67; H, 3.56.

ACCEPTED MANUSCRIPT
4.1.35. 6-chloro-3-((5-methyl-1,3,4-oxadiazol-2-ylthio)methyl)-4H-chromen-4-one (6k).
1
Yield: 79%; Mp 1232-125 °C; H NMR (400 MHz, CDCl3) δ 2.49 (s, 3 H, CH3), 4.25 (s, 2 H,
CH2), 7.44 (d, J = 8.0 Hz, 1 H, ArH), 7.63 (d, J = 8.0 Hz, 1 H, ArH), 8.20 (s, 1 H, ArH), 8.41 (s,
1 H, 2-CH); Ms (m/z) 308 (M+); Anal. calcd for C13H9ClN2O3S: C, 50.57; H, 2.94; N, 9.07.
Found: C, 50.41; H, 3.18; N, 9.12.
4.1.36. 6-chloro-3-((5-methyl-1,3,4-thiadiazol-2-ylthio)methyl)-4H-chromen-4-one (6l).
1
Yield: 81%; Mp 157 -159 °C; H NMR (400 MHz, CDCl3) δ 2.49 (s, 3 H, CH3), 4.25 (s, 2 H,
CH2), 7.46 (d, J = 8.0 Hz, 1 H, ArH), 7.64 (d, J = 8.0 Hz, 1 H, ArH), 8.10 (s, 1 H, ArH), 8.40 (s,
1 H, 2-CH); Ms (m/z) 324 (M+); Anal. calcd for C13H9ClN2O2S2: C, 48.07; H, 2.79; N, 8.62.
Found: C, 48.22; H, 2.93; N, 8.56.
4.1.37. 3-(5-methyl-1,3,4-thiadiazol-2-ylthio)-4H-chromen-4-one (6m). Yield: 80%; Mp
75 -76 °C; 1H NMR (400 MHz, CDCl3) δ 2.71 (s, 3 H, CH3), 7.46-7.52 (m, 2 H, ArH), 7.73 (t, J
= 8.0 Hz, 1 H, ArH), 8.25 (d, J = 8.0 Hz,1 H, ArH), 8.51 (s, 1 H, 2-CH); Ms (m/z) 276 (M+);
Anal. Calcd. for C12H8N2O2S2: C, 52.16; H, 2.92; N, 10.14.. Found: C, 51.95; H, 3.19; N, 10.01.
4.1.38. 2-methyl-3-(5-methyl-1,3,4-oxadiazol-2-ylthio)-4H-chromen-4-one (6n). Yield:
1
80%; Mp 178 -180 °C; H NMR (400 MHz, CDCl3) δ 2.51 (s, 3 H, CH3), 2.61 (s, 3 H, CH3),
7.30 (d, J = 8.0 Hz, 1 H, ArH), 7.59 (t, J = 8.0 Hz, 1 H, ArH), 7.69 (t, J = 8.0 Hz, 1 H, ArH),
8.21 (d, J = 8.0 Hz,1 H, ArH), 8.51 (s, 1 H, 2-CH); Ms (m/z) 276 (M+); Anal. Calcd. for
C13H10N2O3S: C, 56.92; H, 3.67; N, 10.21. Found: C, C, 56.81; H, 3.90; N, 10.12.
4.1.39. 4-((5-amino-1,3,4-thiadiazol-2-ylthio)methyl)-2H-benzo[h]chromen-2-one (7a).
Yield: 79%; Mp 212-214 °C; 1H NMR (400 MHz, DMSO-d6) δ 4.60 (s, 2 H, CH2), 6.43 (s, 1 H,
3-CH), 7.44 (s, 1 H, 3-CH), 7.70-7.75 (m, 2 H, ArH), 7.91 (d, J = 8.8 Hz,1 H, ArH), 7.97 (d, J =

ACCEPTED MANUSCRIPT
8.8 Hz, 1 H, ArH), 8.07 (t, J = 8.4 Hz,1 H, ArH), 8.38(d, J = 7.2 Hz, 1 H, ArH); Ms (m/z) 341
(M+); Anal. calcd for C16H11N3O2S2: C, 56.29; H, 3.25; N, 12.31. Found: C, 56.06; H, 3.49; N,
12.56.
4.1.40.
4-((5-((5,7-dimethyl-[1,2,4]triazolo[1,5-a]pyrimidin-2-ylthio)methyl)-1,3,4-
thiadiazol-2-ylthio)methyl)-2H-benzo[h]chromen-2-one (7b). Yield: 87%; Mp 161-163 °C;
1H NMR (400 MHz, CDCl3) δ 2.54 (s, 3 H, CH3), 2.64 (s, 3 H, CH3), 4.35 (s, 2 H, CH2), 4.89 (s,
2 H, CH2), 6.59 (s, 1 H, 3-CH), 7.12 (s, 1 H, Het-ArH), 7.71-7.76 (m, 2 H, ArH), 7.89 (t, J = 8.8
Hz, 1 H, ArH), 7.96 (d, J = 8.4 Hz, 1 H, ArH), 8.05 (d, J = 6.8 Hz, 1 H, ArH), 8.32 (d, J = 7.2
Hz, 1 H, ArH); Ms (m/z) 518 (M+); Anal. calcd for C24H18N6O2S3: C, 55.58; H, 3.50; N, 16.20.
Found: C, 55.35; H, 3.71; N, 16.31.
4.1.41. 4-((benzo[d]oxazol-2-ylthio)methyl)-6-hydroxy-5-methyl-2H-chromen-2-one
(7c). Yield: 78%; Mp 145-147 °C; 1H NMR (400 MHz, DMSO-d6) δ 2.54 (s, 3 H, CH3), 2.64
(s, 3 H, CH3), 4.35 (s, 2 H, CH2), 4.89 (s, 2 H, CH2), 6.59 (s, 1 H, 3-CH), 7.12 (s, 1 H, Het-
ArH), 7.71-7.76 (m, 2 H, ArH), 7.89 (t, J = 8.8 Hz, 1 H, ArH), 7.96 (d, J = 8.4 Hz, 1 H, ArH),
8.05 (d, J = 6.8 Hz, 1 H, ArH), 8.32 (d, J = 7.2 Hz, 1 H, ArH); Ms (m/z) 339 (M+); Anal. calcd
for C18H13NO4S: C, 63.71; H, 3.86; N, 4.13. Found: C, 63.56; H, 3.98; N, 4.10.
4.1.42. 4-((benzo[d]thiazol-2-ylthio)methyl)-6-hydroxy-5-methyl-2H-chromen-2-one
(7d). Yield: 75%; Mp 136-137 °C; 1H NMR (400 MHz, DMSO-d6) δ 2.54 (s, 3 H, CH3), 2.64
(s, 3 H, CH3), 4.35 (s, 2 H, CH2), 4.89 (s, 2 H, CH2), 6.59 (s, 1 H, 3-CH), 7.12 (s, 1 H, Het-
ArH), 7.71-7.76 (m, 2 H, ArH), 7.89 (t, J = 8.8 Hz, 1 H, ArH), 7.96 (d, J = 8.4 Hz, 1 H, ArH),
8.05 (d, J = 6.8 Hz, 1 H, ArH), 8.32 (d, J = 7.2 Hz, 1 H, ArH); Ms (m/z) 355 (M+); Anal. calcd
for C18H13NO3S2: C, 60.83; H, 3.69; N, 3.94. Found: C, 60.76; H, 3.87; N, 3.89.

ACCEPTED MANUSCRIPT
4.1.43. 4-((5-((5,7-dimethyl-[1,2,4]triazolo[1,5-a]pyrimidin-2-ylthio)methyl)-1,3, 4-
thiadiazol-2-ylthio)methyl)-6-hydroxy-5-methyl-2H-chromen-2-one (7e). Yield: 82%; Mp
150-152 °C; 1H NMR (400 MHz, DMSO-d6) δ 2.40 (s, 3 H, CH3), 2.56 (s, 3 H, CH3), 2.70 (s, 3
H, CH3), 4.72 (s, 2 H, CH2), 4.90 (s, 2 H, CH2), 5.65 (s, 1 H, 3-CH), 6.16 (s, 1 H, Het-ArH),
6.68 (s, 1 H, ArH), 7.15 (s, 1 H, ArH); Ms (m/z) 498 (M+); Anal. calcd for C21H18ClN6O3S3: C,
50.59; H, 3.64; N, 16.86. Found: C, 50.35; H, 3.89; N, 16.82.
4.1.44. 4-((1H-benzo[d]imidazol-2-ylthio)methyl)- 7-hydroxy-5-methyl-2H-chromen-
2-one (7f). Yield: 76%; Mp 165-167 °C; 1H NMR (400 MHz, DMSO-d6) δ 2.16 (s, 3 H, CH3),
4.73 (s, 2 H, CH2), 6.32 (s, 1 H, 3-CH), 6.89 (d, J = 8.8 Hz, 1 H, ArH), 7.16 (bs, 2 H, ArH),
7.41 (b, 1 H, ArH), 7.55 (b, 1 H, ArH), 7.66 (d, J = 8.8 Hz, 1 H, ArH), 10.54 (s, 1 H, NH),
12.70 (s, 1 H, OH); 13C-NMR (100 MHz, DMSO-d6) δ 8.8, 30.7, 110.2, 110.6, 111.1, 111.8,
117.6, 121.4, 121.9, 123.1, 135.5, 143.5, 148.4, 152.1, 153.2, 159.1, 160.2, 162.2; Ms (m/z) 338
(M+); Anal. calcd for C18H14N2O3S: C, 63.89; H, 4.17; N, 8.28. Found: C, 63.66; H, 4.01; N,
8.03.
4.1.45. 4-((benzo[d]oxazol-2-ylthio)methyl)-7,8-dihydroxy-2H-chromen-2-one (7g).
Yield: 79%; Mp 142-145 °C; 1H NMR (400 MHz, DMSO-d6) δ 4.79 (s, 2 H, CH2), 6.43 (s, 1 H,
3-CH), 6.91 (d, J = 8.8 Hz, 1 H, ArH), 7.31-7.36 (m, 2 H, ArH), 7.63-7.70 (m, 3 H, ArH), 10.57
(s, 1 H, OH); Ms (m/z) 341 (M+); Anal. calcd for C17H11NO5S: C, 59.82; H, 3.25; N, 4.10.
Found: C, 59.67; H, 3.42; N, 4.01.
4.1.46.
N-(4-((4,6-dimethylpyrimidin-2-ylthio)methyl)-2-oxo-2H-chromen-7-yl)-
acetamide (7h). Yield: 89%; Mp 178-179;1H NMR (400 MHz, CDCl3) δ 2.42 (s, 6 H, CH3),
2.44 (s, 3 H, CH3), 4.34 (s, 2 H, CH2), 6.50 (s, 1 H, 3-CH), 6.74 (s, 1 H, Het-ArH), 7.35(d, J =

ACCEPTED MANUSCRIPT
8.0 Hz, 1 H, ArH), 7.46 (d, J = 8.0 Hz,1 H, ArH), 7.94 (s, 1 H, ArH); Ms (m/z) 355 (M+); Anal.
calcd for C18H17N3O3S: C, 60.83; H, 4.82; N, 11.82. Found: C, 60.67; H, 4.99; N, 11.67.
4.1.47. N-(4-((5-((5,7-dimethyl-[1,2,4]triazolo[1,5-a]pyrimidin-2-ylthio)methyl)- 1,3,4-
thiadiazol-2-yl-thio)methyl)-2-oxo-2H-chromen-7-yl)acetamide (7i). Yield: 80%; Mp 167-
169 °C;1H NMR (400 MHz, DMSO-d6) δ 2.56 (s, 3 H, CH3), 2.66 (s, 3 H, CH3), 3.71 (s, 3 H,
CH3), 4.72 (s, 2 H, CH2), 4.89 (s, 2 H, CH2), 5.84 (s, 1 H, 3-CH), 6.32 (s, 1 H, Het-ArH), 6.98
(d, J = 8.4 Hz, 1 H ArH), 7.17 (d, J = 8.4 Hz, 1 H ArH), 9.71 (s, 1 H, NH); Ms (m/z) 525 (M+);
Anal. calcd for C22H19N7O3S3: C, 50.27; H, 3.64; N, 18.65. Found: C, 50.10; H, 3.72; N, 18.57.
4.1.48. 3-((5-amino-1,3,4-thiadiazol-2-ylthio)methyl)quinazolin-4(3H)-one (8a). Yield:
1
85%; Mp 176-178 °C; H NMR (400 MHz, DMSO-d6) δ 5.51 (s, 2 H, CH2), 7.51 (s, 2 H, NH2),
7.59 (d, J = 8.4 Hz, 1 H ArH), 7.70 (d, J = 8.4 Hz, 1 H ArH), 7.87 (t, J = 7.6 Hz, 1 H ArH), 8.18
13
(d, J = 8.4 Hz, 1 H ArH), 8.32 (s, 1 H, 2-CH); C-NMR (100 MHz, DMSO-d6) δ 49.6, 121.1,
126.1, 127.3, 134.7, 146.3, 146.8, 147.5, 159.5, 171.3; Ms (m/z) 291 (M+); Anal. calcd for
C11H9N5OS2: C, 45.35; H, 3.11; N, 24.04. Found: C, 45.20; H, 3.33; N, 24.10.
4.1.49. 3-((benzo[d]oxazol-2-ylthio)methyl)quinazolin-4(3H)-one (8b). Yield: 89%; Mp
142 -144 °C; 1H NMR (400 MHz, CDCl3) δ 5.79 (s, 2 H, CH2), 7.30-7.37 (m, 2 H, ArH), 7.44
(d, J = 7.6 Hz, 1 H, ArH), 7.52 (t, J = 7.6 Hz, 1 H, ArH), 7.65 (d, J = 8.0 Hz, 1 H, ArH), 7.70 (d,
J = 8.4 Hz, 1 H, ArH), 7.76 (t, J = 8.0 Hz, 1 H, ArH), 8.34 (d, J = 8.0 Hz, 1 H, ArH), 8.84 (s, 1
H, 2-CH); Ms (m/z) 309 (M+); Anal. calcd for C16H11N3O2S: C, 62.12; H, 3.58; N, 13.58. Found:
C, 62.00; H, 3.71; N, 13.61.
4.1.50. 3-((benzo[d]thiazol-2-ylthio)methyl)quinazolin-4(3H)-one (8c). Yield: 94%; Mp
140-142 °C; 1H NMR (400 MHz, CDCl3) δ 5.87 (s, 2 H, CH2), 7.31-7.35 (m, 2 H, ArH), 7.47 (t,

ACCEPTED MANUSCRIPT
J = 8.0 Hz, 1 H, ArH), 7.52 (t, J = 7.6 Hz, 1 H, ArH), 7.69 (d, J = 8.0 Hz, 1 H, ArH), 7.76 (d, J
= 8.0 Hz, 1 H, ArH), 7.95 (t, J = 8.0 Hz, 1 H, ArH), 8.33 (d, J = 8.0 Hz, 1 H, ArH), 8.82 (s, 1 H,
2-CH); Ms (m/z) 325 (M+); Anal. calcd for C16H16N3OS2: C, 59.06; H, 3.41; N, 12.91. Found: C,
58.90; H, 3.65; N, 12.88.
4.1.51. 3-((4,6-dimethylpyrimidin-2-ylthio)methyl)quinazolin-4(3H)-one (8d). Yield:
90%; Mp 151-153 °C; 1H NMR (400 MHz, DMSO-d6) δ 2.46 (s, 6 H, CH3), 5.70 (s, 2 H, CH2),
6.78 (s, 1 H, Het-CH), 7.50 (t, J = 8.0 Hz, 1 H, ArH), 7.67 (d, J = 8.0 Hz, 1 H, ArH), 7.75 (t, J =
7.6 Hz, 1 H, ArH), 8.32 (d, J = 8.0 Hz,1 H, ArH), 8.71 (s, 1 H, 2-CH); Ms (m/z) 298 (M+); Anal.
calcd for C15H14N4OS: C, 60.38; H, 4.73; N, 18.78. Found: C, 60.10; H, 4.87; N, 18.67.
4.1.52. 3-((5,7-dimethyl-[1,2,4]triazolo[1,5-a]pyrimidin-2-ylthio) methyl) quinazolin-
4(3H)-one (8e). Yield: 90%; Mp 176-178 °C; 1H NMR (400 MHz, CDCl3) δ 2.66 (s, 3 H, CH3),
2.73 (s, 3 H, CH3), 5.83 (s, 2 H, CH2), 6.79 (s, 1 H, Het-CH), 7.50 (t, J = 8.0 Hz, 1 H, ArH),
7.66 (d, J = 8.0 Hz, 1 H, ArH), 7.75 (t, J = 8.0 Hz, 1 H, ArH), 8.32 (d, J = 8.0 Hz,1 H, ArH),
8.77 (s, 1 H, 2-CH); Ms (m/z) 338 (M+); Anal. calcd for C16H14lN6OS: C, 56.79; H, 4.17; N,
24.84. Found: C, 56.67; H, 4.00; N, 24.71.
4.1.53. 3-((4-oxo-4H-thiochromen-2-ylthio)methyl)quinazolin-4(3H)-one (8f). Yield:
1
92%; Mp 156-158 °C; H NMR (400 MHz, CDCl3) δ 5.50 (s, 2 H, CH2), 7.21-7.31 (m, 2 H,
ArH), 7.54-7.62 (m, 2 H, ArH), 7.72 (d, J = 8.0 Hz, 1 H, ArH), 7.81 (t, J = 7.8 Hz, 1 H, ArH),
8.11 (s, 1 H, Het-CH), 8.46 (d, J = 8.0 Hz, 1 H, ArH), 8.49 (d, J = 8.0 Hz, 1 H, ArH), 8.82 (s, 1
H, 2-CH); Ms (m/z) 352 (M+); Anal. calcd for C18H12N2O2S2: C, 61.34; H, 3.43; N, 7.95. Found:
C, 61.22; H, 3.61; N, 7.86.
4.1.54. 3-((benzo[d]oxazol-2-ylthio)methyl)-8-chloroquinazolin-4(3H)-one (8g). Yield:

ACCEPTED MANUSCRIPT
1
86%; Mp 156 -158 °C; H NMR (400 MHz, CDCl3) δ 5.79 (s, 2 H, CH2), 7.30-7.37 (m, 2 H,
ArH), 7.44 (d, J = 7.6 Hz, 1 H, ArH), 7.52 (t, J = 7.6 Hz, 1 H, ArH), 7.65 (d, J = 8.0 Hz, 1 H,
ArH), 7.70 (d, J = 8.4 Hz, 1 H, ArH), 7.76 (t, J = 8.0 Hz, 1 H, ArH), 8.34 (d, J = 8.0 Hz, 1 H,
ArH), 8.84 (s, 1 H, 2-CH); Ms (m/z) 343 (M+); Anal. calcd for C16H10ClN3O2S: C, 55.90; H,
2.93; N, 12.22. Found: C, 55.76; H, 3.12; N, 12.14.
4.1.55. 3-((benzo[d]thiazol-2-ylthio)methyl)-8-chloroquinazolin-4(3H)-one (8h). Yield:
1
89%; Mp 161-163 °C; H NMR (400 MHz, CDCl3) δ 5.87 (s, 2 H, CH2), 7.31-7.35 (m, 2 H,
ArH), 7.47 (t, J = 8.0 Hz, 1 H, ArH), 7.52 (t, J = 7.6 Hz, 1 H, ArH), 7.69 (d, J = 8.0 Hz, 1 H,
ArH), 7.76 (d, J = 8.0 Hz, 1 H, ArH), 7.95 (t, J = 8.0 Hz, 1 H, ArH), 8.33 (d, J = 8.0 Hz, 1 H,
ArH), 8.82 (s, 1 H, 2-CH); Ms (m/z) 359 (M+); Anal. calcd for C16H10ClN3OS2: C, 53.40; H,
2.80; N, 11.68. Found: C, 53.31; H, 2.67; N, 11.47.
4.1.56. 8-chloro-3-((4,6-dimethylpyrimidin-2-ylthio)methyl)quinazolin-4(3H)-one (8i).
Yield: 92%; Mp 171-173 °C; 1H NMR (400 MHz, DMSO-d6) δ 2.46 (s, 6 H, CH3), 5.70 (s, 2 H,
CH2), 6.78 (s, 1 H, Het-CH), 7.50 (t, J = 8.0 Hz, 1 H, ArH), 7.67 (d, J = 8.0 Hz, 1 H, ArH), 7.75
(t, J = 7.6 Hz, 1 H, ArH), 8.32 (d, J = 8.0 Hz,1 H, ArH), 8.71 (s, 1 H, 2-CH); Ms (m/z) 332 (M+);
Anal. calcd for C15H13ClN4OS: C, 54.13; H, 3.94; N, 16.83. Found: C, 54.02; H, 3.87; N, 16.71.
4.1.57.
8-chloro-3-((5,7-dimethyl-[1,2,4]triazolo[1,5-a]pyrimidin-2-ylthio)methyl)-
quinazolin-4(3H)-one (8j). Yield:90%; Mp 181-183 °C; 1H NMR (400 MHz, CDCl3) δ 2.66 (s,
3 H, CH3), 2.73 (s, 3 H, CH3), 5.83 (s, 2 H, CH2), 6.79 (s, 1 H, Het-CH), 7.50 (t, J = 8.0 Hz, 1 H,
ArH), 7.66 (d, J = 8.0 Hz, 1 H, ArH), 7.75 (t, J = 8.0 Hz, 1 H, ArH), 8.32 (d, J = 8.0 Hz,1 H,
ArH), 8.77 (s, 1 H, 2-CH); Ms (m/z) 372 (M+); Anal. calcd for C16H13CllN6OS: C, 51.54; H,
3.51; N, 22.54. Found: C, 51.45; H, 3.21; N, 22.61.

ACCEPTED MANUSCRIPT
4.1.58. 8-chloro-3-((5-((5,7-dimethyl-[1,2,4]triazolo[1,5-a]pyrimidin-2-ylthio) methyl)-
1,3,4-thiadiazol-2-ylthio)-methyl)quinazolin-4(3H)-one (8k). Yield: 94%; Mp 189-192
°C;1H NMR (400 MHz, CDCl3) δ 5.87 (s, 2 H, CH2), 7.31-7.35 (m, 2 H, ArH), 7.47 (t, J = 8.0
Hz, 1 H, ArH), 7.52 (t, J = 7.6 Hz, 1 H, ArH), 7.69 (d, J = 8.0 Hz, 1 H, ArH), 7.76 (d, J = 8.0
Hz, 1 H, ArH), 7.95 (t, J = 8.0 Hz, 1 H, ArH), 8.33 (d, J = 8.0 Hz, 1 H, ArH), 8.82 (s, 1 H, 2-
CH); Ms (m/z) 502 (M+); Anal. calcd for C16H16N3OS2: C, 45.37; H, 3.01; N, 22.28. Found: C,
45.30; H, 2.96; N, 22.17.
4.1.59. 8-chloro-3-((4-oxo-4H-thiochromen-2-ylthio)methyl)quinazolin-4(3H)-one (8l).
Yield: 86%; Mp 171-173 °C;1H NMR (400 MHz, CDCl3) δ 5.50 (s, 2 H, CH2), 7.21-7.31 (m, 2
H, ArH), 7.54-7.62 (m, 2 H, ArH), 7.72 (d, J = 8.0 Hz, 1 H, ArH), 7.81 (t, J = 7.8 Hz, 1 H, ArH),
8.11 (s, 1 H, Het-CH), 8.46 (d, J = 8.0 Hz, 1 H, ArH), 8.49 (d, J = 8.0 Hz, 1 H, ArH), 8.82 (s, 1
H, 2-CH); Ms (m/z) 386 (M+); Anal. calcd for C18H11ClN2O2S2: C, 55.88; H, 2.87; N, 7.24.
Found: C, 55.77; H, 2.70; N, 7.17.
4.2. Pharmacology
4.2.1. Cell proliferation measured with the MTT assay [19]. Cells were seeded in 96-
well microplates at 8000 cells/well. The test compounds were added, and cells were incubated
for 72 h. Then, 20 µL (0.5 mg/mL, final concentration) of MTT (Sigma, USA) was added to
each well, and cells were incubated for 4 h. MTT was converted to a blue formazan product by
mitochondrial succinate dehydrogenase. This product was eluted from cells by addition of 150
mL DMSO. Absorbance at 570 nm was determined by a NJ-2300 microplate
spectrophotometer. For each assay, three different experiments were performed in triplicate.
The results were statistically evaluated with the Student’s t-test and presented as means ± SEM.

ACCEPTED MANUSCRIPT
4.2.2. Flow cytometry Analysis [20]. The effect of compound 6b on cancer cells was
assessed by examining cell cycle phase distribution with flow cytometry. Cells were grown to
about 70% confluence in 6-well microplates, and then treated with different concentrations of
IIa2. After 48 h, cells were harvested by trypsinization, washed in PBS, and fixed in 70% ice
cold (4 °C) ethanol overnight. Then, cells were washed with PBS, incubated with RNase (100
µg/mL final concentration) at 37 °C for 30 min, stained with propidium iodide (50 µg/mL final
concentration), and analyzed by flow cytometry (Beckman Coulter). The results were
statistically evaluated with the Student’s t-test and presented as means ± SEM.
Acknowledgments
This work was supported in part by the National Natural Science Foundation of China (No.
20925206), the National Key Technologies R&D Program (2011BAE06B05), and Natural
Science Foundation of Jiangsu Province of China (No. BK2011086).
References and Notes
[1] O. N. Voskresensky, A. P. Levitsky, Flavonoids as anticancer agents: structure-activity relationship
study, Curr. Med. Chem. 2 (2002) 691-714.
[2] Y. Li, H. Fang, W. Xu, Recent advance in the research of flavonoids as anticancer agents, Mini. Rev.
Med. Chem. 7 ( 2007) 663-678.
[3] H.K.Wang, The therapeutic potential of flavonoids, Expert Opin. Investig. Drugs. 9 (2000) 2103-2109.
[4] W. Ren, Z. Qiao, H. Wang, L. Zhang, Flavonoids: promising anticancer agents, Med. Res. Rev. 23
(2003) 519-534.
[5] (a) L. R .Kelland, Flavopiridol, the first cyclin-dependent kinase inhibitor to enter the clinic: current
status, Expert Opin. Invest. Drugs. 9 (2000) 2903-2911;
(b) A. M. Senderowicz, E. A. Sausville, Preclinical and clinical development of cyclin-dependent kinase
modulators, J. Natl. Cancer Inst. 92 (2000) 376-387.
[6] H.K.Wang, K. F. B astow, L. K. Cosentino, K. H. Lee, Antitumor agents. 166. synthesis and biological
evaluation of 5,6,7,8-substituted-2-phenylthiochromen-4-ones, J. Med. Chem. 39 (1996) 1975-1980.
[7] T. Kataoka,; S. Watanab, E. Mori, R. Kanomoto, S. Tanimura, M. S. Kohno, Synthesis and structure–

ACCEPTED MANUSCRIPT
activity relationships of thioflavone derivatives as specific inhibitors of the ERK-MAP kinase signaling
pathway, Bioorg. Med. Chem. 12 (2004) 2397-2407.
[8] W. Huang, M. Z. Liu, Y. Li, Y. Tan, G. F. Yang, Design, syntheis and antitumor activity of novel
chromone and aurone derivatives. Bioorg. Med. Chem. 15 (2007) 5191-5197.
[9] W. Huang, Y. Ding, Y. Miao, G. F. Yang, Synthesis and antitumor activity of novel dithiocarbamate
substituted chromones, Eur. J. Med. Chem. 44 (2009) 3687-3696.
[10] J. Bols, L. Anglada, S. Gubert, J. M. Planas, J. Agut, M. Prncep, D. Fuente, A. Sacristn, J. A. Ortiz, 7-
[3-(1-Piperidinyl)propoxy]chromenones as Potential atypical antipsychotics. 2. pharmacological profile
of 7-[3-[4-(6-fluoro-1,2-benzisoxazol-3-yl)-piperidin-1-yl]propoxy]-3-(hydroxymethyl)
chromen-4-one (Abaperidone, FI-8602), J. Med. Chem. 41 (1998) 5402-5409.
[11] J. Bolos, T. Loscertales, J. Nieto, A. Sacristan, J. A. Ortiz, A new efficient synthesis of 3-
(hydroxymethyl)-4H-chromen-4-ones , J. Heterocycl. Chem. 37 (2000) 1203-1208.
[12] R. B. Gammill, S. A. Nash, S. A. Mizsak, The addition of amines to 3-bromochromone and 6-bromo-
furochromone. an unexpected ring contraction of the pyrone ring ,Tetrahedron. Lett. 24 (1983) 3435-
3438.
[13] L. L. Woods, J. Sapp, A new one-step synthesis of substituted coumarins, J. Org. Chem. 27 (1962)
3703-3705.
[14] S. D. Cho, J. Hwang, H. K. K im, H. S. Yim, J. J. Kim, S. G. Lee, Y. J. Yoon, Synthesis and
photophysical properties of N-styrylazinones, J. Heterocyclic Chem. 44 (2007) 951- 960.
[15] Z. Z. Zhou, P. L. Zhao, W. Huang, G. F. Yang, A selective transformation of flavanones to 3-
bromoflavones and flavones under microwave irradiation, Adv. Synth. Catal. 348 (2006) 63-67.
[16] Z. Z. Zhou, G. F. Yang, Insecticidal lead identification by screening benzopyrano[4,3-c] pyrazol-3(2H)-
ones library constructed from multiple-parallel synthesis under microwave irradiation, Bioorg. Med.
Chem. 14 (2006) 8666-8674.
[17] W. Huang, P. L. Zhao, C. L. Liu, Q. Chen, Z. M. Liu, G. F. Yang, Design, synthesis, and fungicidal
activities of new strobilurin derivatives, J. Agric. Food Chem. 55 (2007) 3004-3010.
[18] (a) Full crystallographic details has been deposited at the Cambridge Crystallographic Data Center and
allocated the deposition number CCDC 715189 (Ih);
(b) G. M. Sheldrick, (2001). SHELXTL (Version 5.0). University of Gőttingen: Germany, 2001;
(c) Bruker SMART V5.628, SAINT V6.45. & SADABS Bruker AXS Inc., Madison, Wisconsin, USA,
2001.
[19] T. J. Mosmann, Rapid colorimetric assay for cellular growth and survival: application to proliferation
and cytotoxicity assays, Immunol. Methods. 65 (1983) 55-63.
[20] Z. Darzynkiewicz, E. Bednery, Analysis of apoptotic cells by flow and laser scanning cytometry,
Methods Enzymol. 322 (2000) 18-39.

ACCEPTED MANUSCRIPT
Captions:
Figure 1. Reported thio-flavonoids with antitumor activity
Figure 2. Design of the title compounds
Figure 3. X-ray crysrtal structures of 5h
Figure 4. SAR of 3-thio-chromones 6
Figure 5. Cell cycle arrest of SW-480 cell line by compound 6b at different concentrations after
48h treatment
Scheme 1. Synthesis of diversified thio-flavonoids 5, 6, 7 and 8
Scheme 2. Microwave-assisted synthesis of representative compound 5f
Table 1. Antiproliferative activity of the synthesized derivatives
Table 2. Effects of 6b on cell cycle progression

ACCEPTED MANUSCRIPT
N
N
OH
O
OH
H
H
HO
HO
O
S
R
Cl
OH
O
1
OH
O
2
Flavopiridol
O
S
O
O
R3
R1
n
S
N
R2
R
S
O
3
4
Figure 1 Reported thio-flavonoids with antitumor activity
Figure 2 Design of the title compounds
Figure 3 X-ray crysrtal structures of 5h

ACCEPTED MANUSCRIPT
O
N
N
N
N
N
N
S
N
H2N
S
H1
H8
H8
O
O
S
S
S
N
H2N
N
N
H
H5
HN
H4
N
S
N
H3
N
S
n
6'-H > 6'-Cl
2'-H > 2'-Me
>
>
H11
H7
H8
R
N
H2
N
H2N
H2N
N
O
N
N
H8
S
O
N
H8
S
N
N
N
6
S
N
N
N
N
N
N
H6
H12
H10
H8
H13
O
n = 1 >> 0
H14
Figure 4 SAR of 3-thio-chromones 6
Figure 5 Cell cycle arrest of SW-480 cell line by compound 6b at different concentrations after
48h treatment.