The synthesis, characterization, and electrochemical investigation of novel thio- and alkoxy-substituted benzoquinone derivatives

Article abstract of DOI:10.1080/10426507.2013.829833

Novel thio- and alkoxy-substituted benzoquinone derivatives were synthesized from the reactions of p-chloranil (1) and related nucleophiles in a sodium carbonate (Na₂C_O) solution of acetonitrile or in chloroform with Et₃N. The structures of novel compounds were characterized by using microanalysis, FTIR, ¹H NMR, ¹³C NMR, MS, CV, and fluorescence spectroscopy. [Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental files: Additional text and figures.]

Full text of DOI:10.1080/10426507.2013.829833

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The Synthesis, Characterization,
and Electrochemical Investigation of
Novel Thio- and Alkoxy-Substituted
Benzoquinone Derivatives
Cemil Ibis a , Sibel Sahınler Ayla a & Senol Yavuz a
a Department of Chemistry, Faculty of Engineering , Istanbul
University , 34320 , Avcilar , Istanbul , Turkey
Accepted author version posted online: 20 Aug 2013.Published
online: 12 Mar 2014.
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To cite this article: Cemil Ibis , Sibel Sahınler Ayla & Senol Yavuz (2014) The Synthesis,
Characterization, and Electrochemical Investigation of Novel Thio- and Alkoxy-Substituted
Benzoquinone Derivatives, Phosphorus, Sulfur, and Silicon and the Related Elements, 189:4, 492-502,
DOI: 10.1080/10426507.2013.829833
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Phosphorus, Sulfur, and Silicon, 189:492–502, 2014
Copyright ꢀC Taylor & Francis Group, LLC
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426507.2013.829833
THE SYNTHESIS, CHARACTERIZATION,
AND ELECTROCHEMICAL INVESTIGATION
OF NOVEL THIO- AND ALKOXY-SUBSTITUTED
BENZOQUINONE DERIVATIVES
Cemil Ibis, Sibel Sahınler Ayla, and Senol Yavuz
Department of Chemistry, Faculty of Engineering, Istanbul University, 34320
Avcilar, Istanbul, Turkey
GRAPHICAL ABSTRACT
Abstract Novel thio- and alkoxy-substituted benzoquinone derivatives were synthesized from
the reactions of p-chloranil (1) and related nucleophiles in a sodium carbonate (Na2CO3)
solution of acetonitrile or in chloroform with Et3N. The structures of novel compounds were
characterized by using microanalysis, FTIR, 1H NMR, 13C NMR, MS, CV, and fluorescence
spectroscopy.
[Supplementary materials are available for this article. Go to the publisher’s online edition of
Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental
files: Additional text and figures.]
Keywords p-Chloranil; thioalcohols; mercaptans; coumarine
Received 23 April 2013; accepted 25 July 2013.
We thank the Research Fund of Istanbul University for financial support to this work.
Address correspondence to Cemil Ibis, Department of Chemistry, Faculty of Engineering, Istanbul Univer-
sity, 34320 Avcilar, Istanbul, Turkey. E-mail: ibiscml@istanbul.edu.tr
492

THIO/ALKOXY-SUBSTITUTED BENZOQUINONE DERIVATIVES
493
INTRODUCTION
Nucleophilic additions to quinone structures have been widely studied in synthetic
chemistry.1–6 Heterocyclic ring quinone systems are found in biologically and pharma-
cologically active compounds.7 It is also known from the literature that substitution of
quinonoid structure with N-, S-, and O-nucleophiles leads to an observable increase in
biological activity.8 Many natural products from marine or plant sources involve quinonoid
structures with important biological activity properties.9–11
Quinones also have been used in dye chemistry.12 Quinone dyes have strong in-
tramolecular charge-transfer chromophoric system. The compounds containing quinone
structure have ability to undergo redox cycling to generate the reactive oxygen species
(ROS) destroying the tumor cells.13
The aim of this study is to synthesize the novel benzoquinone compounds and char-
acterize them with spectral methods.
RESULTS AND DISCUSSION
The novel benzoquinone derivatives 4 and 5 were obtained by the reaction of p-
chloranil 1 and different molar equivalent of pentafluorothiophenol 2 in ethanol with sodium
carbonate (Na2CO3) at room temperature (Scheme 1). The molecular ion peak of compound
Scheme 1 Synthetic pathway of novel compounds.

494
C. IBIS ET AL.
4 was identified at m/z 900 in the negative ion mode for ESI technique. The OCH2 protons
of compound 5 appeared at downfield region of 1H NMR spectrum and showed triplets at
4.3 ppm.
The novel benzoquinone derivatives 7a, 7b, 8, and 9 were obtained by the reaction
of p-chloranil 1 and different molar equivalent of 3-mercapto-1-hexanol 6 in ethanol with
sodium carbonate (Na2CO3) at room temperature. It is possible to say compounds 7a and
7b were obtained as an isomeric mixture and gave four carbon signals for C O groups in
benzoquinone unit resonating at 174.5, 175.1, 178.4, and 179.8 ppm. The 13C NMR spectra
of cyclic compound 8 gave only two carbonyl signals at 177.4 and 174.6 ppm as expected.
The IR spectra of tetrakis-substituted compound 9 showed characteristic hydroxyl band
( OH) at 3334 cm−1 and gave one carbonyl signal at 173.1 ppm in 13C NMR because of
the symmetric structure of this compound.
The tetrakis-substituted compound 10 and tris-substituted compound 11 were
obtained by the reaction of p-chloranil 1 and different molar equivalent of 2-(2-
mercaptoethyl)pirazine 3 in chloroform with Et3N. The 13C NMR spectra of compounds 10
gave only one carbonyl signal at 172.6 ppm as a result of the symmetric unit. Furthermore,
the tris-substituted compound 11 gave two carbonyl signals at 173.6 and 169.6 ppm. The
mass spectra of compound 11 in the negative ion mode of ESI technique confirmed the
Scheme 2 Synthesis of novel O-, S-, and S,S-substituted chloranil compounds.

THIO/ALKOXY-SUBSTITUTED BENZOQUINONE DERIVATIVES
495
Figure 1 Excitation (367.07 nm) and emission (468.93 nm) spectra for compound 22 (10−4 M) in chloroform at
room temperature. (Color figure available online).
proposed structure; the deprotonated molecular ion peak was identified at m/z (%) 556
(100).
The novel benzoquinone derivatives 12a, 12b, 13, and 14 were obtained by the
reaction of p-chloranil 1 and 2-(2-mercaptoethyl)pirazine 3 in sodium carbonate (Na2CO3)
solution of ethanol at room temperature. It is possible to say compounds 12a and 12b
were obtained as an isomeric mixture and gave four carbon signals for C O groups in
benzoquinone unit resonating at 178.0, 176.7, 174.5, and 173.9 ppm. The 13C NMR spectra
of compounds 13 gave only one carbonyl signal at 177.4, as a result of symmetric structure
of compound 13. The OCH2 protons of compound 14 appeared at downfield region of
1H NMR spectrum and showed triplets at 4.2 ppm.
The novel alkoxy-substituted benzoquinone derivatives 16 and 18 were synthesized
from the reactions of p-chloranil 1 and related alcohols in potassium carbonate (K2CO3)
solution of acetonitrile (Scheme 2).
The mass spectra of compounds 16 and 18 in the negative ion mode of ESI technique
confirmed the proposed structure; the molecular and deprotonated molecular ion peaks
were identified at m/z (%) 338 (100) and 303 (100), respectively. The monothiosubstituted
compound 20 was obtained from the reaction of p-chloranil 1 and 3-mercapto-1,2,3-triazole
Table 1 Half-wave potentials (for the 1st wave) and electrochemical data for some of the novel benzoquinone
derivatives (10−3 M) in DMF/TBAP 0.1 M, υ = 100 mV s−1
Compound
Ep (Ic) (V)
Ep (IIc) (V)
ꢀEp1a (mV)
E1, 1/2b (V)
p-Chloranil 1
4
8
9
10
14
16
18
20
0.200
−0.152
−0.462
−0.162
−0.276
−0.317
0.083
−0.681
−0.916
−1.048
−0.585
−0.968
—
−0.798
−1.116
−0.356
185
—
74
92
—
—
102
66
0.293
−0.076
−0.425
−0.116
−0.138
−0.158
−0.134
0.331
0.349
0.2186
94
0.265
aꢀEp1 = Epa1 – Epc1.
bE1,1/2 = (Epa1+ Epc1)/2.

496
C. IBIS ET AL.
Figure 2 Cyclic voltammagram of some of the novel benzoquinone derivatives in DMF + 0.1 M TBAP on
Glassy Carbon Electrode (φ3mm) at 0.1 Vs−1. (Color figure available online).
19 in potassium carbonate (K2CO3) solution of acetonitrile. The –NH proton of compound
14 showed doublets at 8.3 ppm. The 2,5-thiosubstituted compound 22 was obtained from
the reaction of p-chloranil 1 and 7-mercapto-4-methyl-coumarine 17 in chloroform with
triethylamine. The 13C NMR spectra of compounds 22 gave only one carbonyl signal at
171.7 as a result of symmetric structure of compound 22.
Quinones show shifts in UV-Vis and fluorescence spectra with a change of redox
state.14 Coumarin group also have fluorescence properties.15,16 The fluorescence properties
of compound 22 was investigated in chloroform solution at room temperature with a 5 nm
slit width for fluorescence spectrometer. The excitation and emission bands were observed
at 367.07 nm and 468.93 nm, respectively (Figure 1).
Quinone-hydroquinone systems are typical examples of organic redox reactions.17,18
The electrochemical behaviors of compounds 1(p-chloranil), 8, 16, 18, and 20 have been
studied in DMF using TBAP 0.10 M as supporting electrolyte at 100 mVs−1. The p-chloranil
(1) is reduced in two steps producing anion radical (semiquinone, Q−) and the dianion
(Q2−). This behavior is typical for the reduction of quinones in aprotic conditions.19,20 In
Table 1, p-chloranil 1 was even reduced at positive potential in the first reduction step
Ep(Ic) = 0.200 V. These can be related to the electron-attracting substituent (Cl atoms)
attached to the ring causing the reduction potential at higher value. Two reversible pairs of
peaks are also detected in compound 16’s voltammogram. (Figure 2).
CONCLUSION
Novel substituted benzoquinone compounds were synthesized from the reactions of
p-chloranil (1) and related nucleophiles in different reaction media. The structures of novel

THIO/ALKOXY-SUBSTITUTED BENZOQUINONE DERIVATIVES
497
1
compounds were characterized by using microanalysis, FTIR, H NMR, 13C NMR, MS,
and CV.
EXPERIMENTAL
Material and Methods
Melting points were determined on a Buchi B-540 melting point apparatus and un-
corrected. Microanalyses were performed on a Thermo Finnigan Flash EA 1112 Series
elemental analyzer. Infrared (IR) spectra were recorded in KBr pellets in Nujol mulls on a
Perkin Elmer Precisely Spectrum One FTIR spectrometer. Fluorescence Spectra were run on
a VARIAN Cary Eclipse Fluorescence Spectrophotometer. 1H NMR and 13C NMR spectra
were recorded in CDCl3 on a Varian UNITY INOVA spectrometer operating at 500 MHz.
Mass spectra were obtained on a Thermo Finnigan LCQ Advantage MAX LC/MS/MS
spectrometer using ion-trap mass analyzer for ESI source. Cyclic voltammetry measure-
ments were performed in a conventional three-electrode cell using a computer-controlled
system of a Gamry Reference 600 Model potentiostat/galvanostat. A glassy carbon disc
was used as a working electrode. The surface of the working electrode was polished before
each run. A platinum wire served as the counter electrode. The reference electrode was
an Ag/AgCl electrode. Electrochemical grade tetrabutylammonium perchlorate (TBAP) in
extra pure DMF was employed as the supporting electrolyte at a concentration of 0.10 M.
Prior to each run, solutions were purged with nitrogen. Measurements were made over a
potential range between 0 and −2 V with a step rate of 0.1 Vs−1
.
Products were isolated by column chromatography on Silica gel (Fluka silica gel 60,
particle size 63–200 μm). TLC plates silica 60F254 (Merck, Darmstadt) and detection was
carried out with ultraviolet light (254 nm). All reagents and solvents were of reagent-grade,
obtained from commercial suppliers, and used without further purification. Selected mass
spectra, 1H and 13C NMR spectra, and cyclic voltammagrams are presented in the online
Supplemental Materials (Figures S1–S11).
General Procedure 1
Sodium carbonate (1.52 g) was dissolved in ethanol (30 mL) and into the resulting
solution, firstly p-chloranil and then thiol were added slowly in small portions. Without
heating, the mixture was stirred for 8 h. The color of the solution quickly changed, and
the extent of the reaction was monitored by TLC. Chloroform (30 mL) was added to the
reaction mixture. The organic layer was separated, washed with water (4 × 30 mL), and
dried with Na2SO4. After the solvent was evaporated, the residue was purified by column
chromatography on silica gel.
General Procedure 2
Potassium carbonate (1.52 g) was dissolved in acetonitrile (30 mL) and into the
resulting solution, firstly p-chloranil and then alcohol were added slowly in small portions.
Without heating, the mixture was stirred for 12 h. The color of the solution quickly changed,
and the extent of the reaction was monitored by TLC. Chloroform (30 mL) was added to
the reaction mixture. The organic layer was separated, washed with water (4 × 30 mL), and

498
C. IBIS ET AL.
dried with Na2SO4. After the solvent was evaporated, the residue was purified by column
chromatography on silica gel.
General Procedure 3
p-Chloranil and thiol were stirred in chloroform as a solvent (40mL). Triethylamine
(1 mL) was added to reaction mixture slowly without heating, and the mixture was stirred
for 12 h. The color of the solution quickly changed, and the extent of the reaction was
monitored by TLC. Chloroform (30 mL) was added to the reaction mixture. The or-
ganic layer was separated, washed with water (4 × 30 mL), and dried with Na2SO4.
After the solvent was evaporated, the residue was purified by column chromatography on
silica gel.
2,3,5,6-Tetrakis(pentafluorophenylthio)-cyclohexa-2,5-diene-1,4-dione (4): Co-
mpound 4 was synthesized from the reaction of 1 (0.5g, 2.033 mmol) with 2 (1.04 mL,
8.1 mmol) according to the general procedure 1.
Orange solid; Yield: 0.26 g (14%); M.p.: 162–163◦C; Rf = 0.52 (petroleum
ether/CHCl3 3:1); Anal. Calcd for C30F20O2S4: C, 40.01; S, 14.24; Found: C, 39.75; S,
12.71. IR (KBr, cm−1): ν = 3010 (Ar H), 2922, 2846 (C H), 1665, 1638 (C O), 1509,
1489 (C C); 13C NMR (125.66 MHz, CDCl3): δ = 108.3 (S CF), 146.4 (CO C S),
135.5, 137.5, 140.4, 141.4, 142.0, 144.0 (Carom), 167.7 ppm (C O); MS (m/z, (relative
abundance,%)): 900 (M−, 100)
6-Ethoxy-2,3,5-tris(pentafluorophenylthio)cyclohexa-2,5-diene-1,4-dione (5):
Compound 5 was synthesized from the reaction of 1 (0.5 g, 2.033 mmol) with 2 (0.77 mL,
6.1 mmol) according to the general procedure 1.
Brown solid; Yield: 0.28 g (18%); M.p.: 102–103◦C; Rf = 0.8 (petroleum ether/CHCl3
4:1); Anal. Calcd. for C26H5F15O3S3: C, 41.83; H, 0.68; S, 12.89; Found: C, 41.83; H, 0.48;
S, 12.20. IR (KBr, cm−1): ν = 2990, 2928 (C H), 1674, 1651 (C O), 1512, 1490 (C C).
1H NMR (499.74 MHz, CDCl3): δ = 4.3 (m, 2H, O CH2), 1.2 ppm (t, 3H, CH3-).13C
NMR (125.66 MHz, CDCl3): δ = 15.3 ( CH3), 70.5 (O CH2), 106.4 (FCarom–S), 125.2
(CO C S), 136.7, 138.7, 140.5, 142.2, 145.7, 147.5 (Carom–F), 155.1 (CO C O), 174.9,
178.8 (C O) ppm.
A mixture of isomer compounds [7-Chloro-8-ethoxy-3,4-dihydro-4-propyl-2H-
benzo[b][1,4]oxathiepine-6,9-dione (7a) and 8-Chloro-7-ethoxy-3,4-dihydro-4-propyl-
2H-benzo[b][1,4]oxathiepine-6,9-dione(7b)]: A mixture of isomer compounds 7a and 7b
was synthesized from the reaction of 1 (1 g, 4.066 mmol) with 6 (0.55 mL, 4.02 mmol)
according to the general procedure 1.
Red oil; Yield: 0.35 g (27%); Rf = 0.67 (CHCl3); Anal. Calcd. for C14H17ClO2S: C,
53.08; H, 5.41; S, 10.12; Found: C, 53.60; H, 6.02; S, 9.39. IR (KBr, cm−1): ν = 2961,
1
2928, 2872 (C H), 1672, 1657 (C O), 1561 (C C). H NMR (499.74 MHz, CDCl3):
δ = 4.8 (m, 2H, C O CH2), 4.4 (m, 2H, O CH2), 3.6 (m, 2H, OCH2 CH2 CH), 2.4
(m, 1H, CH2 CH S), 1.6 (m, 2H, SC CH2), 1.5 (m, 2H, C CH2 CH3), 1.3 (m, 2H,
O CH2 CH3), 0.8 (t, 2H, CH3-) ppm.13C NMR (125.66 MHz, CDCl3): δ = 13.9 ( CH3),
16.1 (O CH2 CH3), 20.2 ( CH2 CH2 CH3), 34.6 (SCH CH2), 37.4 (S CH CH2),
45.6 (O CH2 CH2 CH), 70.8 (O CH2 CH3), 71.6 (O CH2 CH2), 123.9 (C S),
126.4 (C Cl), 152.7, 154.5 ( C O), 174.5, 175.1, 178.4, 179.8 (C O). MS (m/z, (relative
abundance,%)): 317 (M+H+, 42).

THIO/ALKOXY-SUBSTITUTED BENZOQUINONE DERIVATIVES
499
4,8-Dipropyl-3,4,9,10-tetrahydrobenzo[1,2-b:5,4-bꢁ]bis([1,4]oxathiepine)-6,12
(2H,8H)-dione (8): Compound 8 was synthesized from the reaction of 1 (0.5 g,
2.033 mmol) with 6 (0.84 mL, 6.01 mmol) according to the general procedure 1.
Black oil; Yield: 0.08 g (9%); Rf = 0.67 (ethyl acetate/petroleum ether 1:3); Anal.
Calcd. for C18H24O4S2: C, 58.67; H, 6.56; S, 17.40; Found: C, 59.01; H, 7.47; S,
17.24; IR (KBr, cm−1): ν = 2958, 2926, 2869 (C H), 1666, 1637 (C O), 1596, 1555
1
(C C). H NMR (499.74 MHz, CDCl3): δ = 4.4–4.8 (m, 4H, C O CH2), 3.5 (m, 4H,
OCH2 CH2 CH), 2.4 (m, 2H, CH2 CH S), 1.2, 1.4, 1.3, 1.7 (m, 8H, CH2), 0.8 ppm
(m, 6H, CH3-). 13C NMR (125.66 MHz, CDCl3): δ = 12.7 ( CH3), 19.1 ( CH2), 33.3
(SCH CH2), 36.1 (S CH), 44.2 (O CH2 CH2 CH), 70.4 (O CH2), 124.8 (C S),
151.8 ( C O), 172.9, 181.4 (C O) ppm. MS (m/z, (relative abundance,%)): 369 (M+H+,
100).
2,3,5,6-Tetrakis(1-hydroxyhexane-3-ylthio)cyclohexa-2,5-diene-1,4-dione (9):
Compound 9 was synthesized from the reaction of 1 (1 g, 4.066 mmol) with 6 (2.24 mL,
16.2 mmol) according to the general procedure 1.
Brown oil; Yield: 0.17 g (6%); Rf = 0.47 (ethylacetate); Anal. Calcd. for C30H52O6S4
:C, 56.57; H, 8.23; S, 20.14; Found: C, 57.07; H, 8.04; S, 18.02; IR (KBr, cm−1): ν = 3334
( OH), 2957, 2931, 2872 (C H), 1658 (C O), 1486, 1465 (C C). 1H NMR (499.74 MHz,
CDCl3): δ = 3.9, 3.8, 3.7, 3.6 (m, 8H, HO CH2), 1.9, 1.8 (m, 4H, S CH), 1.7, 1.6, 1.5,
1.3, 1.2 (m, 24H, CH2), 0.8 ppm (m, 12H, CH3-). 13C NMR (125.66 MHz, CDCl3):
δ = 12.9 ( CH3), 18.9 ( CH2 CH3), 38.4, 36.4 (SCH CH2), 45.8 (O CH2 CH2),
58.6 (O CH2), 145.8, 148.5, 149.7 (C S), 173.1 (C O) ppm. MS (m/z, (relative abun-
dance,%)): 636 (M−, 100).
2,3,5,6-Tetrakis(2-(pyrazin-2-yl)ethylthio)cyclohexa-2,5-diene-1,4-dione (10):
Compound 10 was synthesized from the reaction of 1 (0.5 g, 2.033 mmol) with 3 (1 mL g,
8.1 mmol) according to the general procedure 3.
Brown oil; Yield: 0.5 g (37%); Rf = 0.21 (EtOH); Anal. Calcd. for C30H28N8O2S4:
C, 54.52; H, 4.27; N, 16.96; S, 19.41; Found: C, 54.53; H, 4.15; N, 16.35; S, 20.15; IR (KBr,
cm−1): ν = 3069, 3050, 3005 (Ar H), 2926, 2837 (C H), 1653 (C O), 1634 (C C).
1H NMR (499.74 MHz, CDCl3): δ = 8.4 (m, 12H, CHarom), 3.4 (m, 8H, CH2-), 3.1 (m,
8H, S CH2) ppm. 13C NMR (125.66 MHz, CDCl3): δ = 33.4, 33.8, 35.1 (CH2), 124.7
( C S), 141.8, 142.7, 143.9, 144.4, 153.7 (N CHarom), 172.6 ppm (C O). MS (m/z,
(relative abundance,%)): 661 (M+H+, 100).
2,3,5-Tris(2-(pyrazin-2-yl)ethylthio)-6-cyclohexa-2,5-diene-1,4-dione (11): Com-
pound 11 was synthesized from the reaction of 1 (1 g, 4.066 mmol) with 3 (1.5 mL,
12.2 mmol) according to the general procedure 3.
Brown oil; Yield: 1.36 g (60%); Rf = 0.6 (ethylacetate); Anal. Calcd. for
C24H21ClN6O2S3: C, 51.74; H, 3.80; N, 15.09; S, 17.27; Found: C, 51.75; H, 3.35; N,
14.55; S, 16.26; IR (KBr, cm−1): ν = 3072, 3037 (Ar H), 2958, 2923, 2853 (C H), 1653
1
(C O), 1577, 1527 (C C). H NMR (499.74 MHz, CDCl3): δ = 8.4 (m, 9H, CHarom),
3.6, 3.5 (m, 6H, CH2-), 3.3, 3.2, 3.1, 3.0 ppm (m, 6H, S CH2). 13C NMR (125.66 MHz,
CDCl3): δ = 32.1, 33.5, 33.9, 34.9, 35.1 (CH2), 120.9 (C Cl), 122.3, 124.4, 126.4
( C S), 141.7, 143.1, 143.8, 153.8 (N CHarom), 173.6, 169.6 (C O) ppm. MS (m/z,
(relative abundance,%)): 556 (M−, 100).
A mixture of isomer compounds [2-(2-(pyrazin-2-yl)ethylthio)-3-Chloro-
5,6-diethoxycyclohexa-2,5-diene-1,4-dione (12a) and 2-(2-(pyrazin-2-yl)ethylthio)-
6-chloro-3,5-diethoxycyclohexa-2,5-diene-1,4-dione (12b)]: A mixture of isomer

500
C. IBIS ET AL.
compounds 12a and 12b was synthesized from the reaction of 1 (1 g, 4.066 mmol) with 3
(1 mL, 8.1 mmol) according to the general procedure 1.
Red oil; Yield: 0.24 g (16%); Rf = 0.3 (CHCl3); Anal. Calcd. for C16H17ClN2O4S:
C, 52.13; H, 4.65; N, 7.60; S, 8.69; Found: C, 52.13; H, 5.32; N, 7.95; S, 8.87; IR (KBr,
cm−1): ν = 3010 (Ar H), 2987, 2977, 2939 (C H), 1682, 1656 (C O), 1625, 1576
1
(C C). H NMR (499.74 MHz, CDCl3): δ = 8.4, 8.3 (d, 3H, CHarom), 4.4, 4.3 (m, 4H,
O CH2-), 3.4 (m, 2H, CH2-), 3.0 (m, 2H, S CH2-), 1.3, 1.2 ppm (m, 6H, CH3-).
13C NMR (125.66 MHz, CDCl3): δ = 14.8 (CH3), 30.4 (S CH2), 34.6 (SCH2 CH2),
69.0 (O CH2), 122.5, 125.0 (C Cl), 125.7, 128.9 (CO C S), 141.7, 143.1, 143.8, 153.8
(N CHarom, Carom), 155.3 (CO C O), 173.9, 174.5, 176.7, 178.0 (C O) ppm. MS (m/z,
(relative abundance,%)): 369 (M+H+, 100).
2,5-Bis(2-(pyrazin-2-yl)ethylthio)-3,6-diethoxycyclohexa-2,5-diene-1,4-dione
(13): Compound 13 was synthesized from the reaction of 1 (1 g, 4.066 mmol) with 3
(1 mL, 8.1 mmol) according to the general procedure 1.
Brown oil; Yield: 0.07 g (3%); Rf = 0.7 (ethylacetate); Anal. Calcd. for
C22H24N4O4S2: C, 55.91; H, 5.12; N, 11.86; S, 13.57; Found: C, 55.90; H, 5.32; N,
11.68; S, 13.42; IR (KBr, cm−1): ν = 3053, 3034 (Ar H), 2980, 2932, 2901 (C H),
1650 (C O), 1558 (C C). 1H NMR (499.74 MHz, CDCl3): δ = 8.4, 8.3 (d, 6H, CHarom),
4.3, 4.2 (m, 4H, O CH2-), 3.3, 3.1 (m, 8H, S CH2-), 1.3, 1.2 ppm (m, 6H-CH3-).
13C NMR (125.66 MHz, CDCl3): δ = 14.5 ( CH3), 30.4 (S CH2), 34.9 (SCH2 CH2),
69.3 (O CH2), 125.2 (C S), 141.0, 142.6, 144.0, 153.7 (N CHarom, Carom), 156.0
(CO C O), 177.4 (C O) ppm. MS (m/z, (relative abundance,%)): 473 (M+H+, 100).
2,3,5-Tris(2-(pyrazin-2-yl)ethylthio)-6-ethoxycyclohexa-2,5-diene-1,4-dione
(14): Compound 14 was synthesized from the reaction of 1 (1 g, 4.066 mmol) with 3
(1 mL, 8.1 mmol) according to the general procedure 1.
Brown oil; Yield: 0.2 g (8%); Rf = 0.33 (Ethylacetate); Anal. Calcd. for
C26H26N6O3S3: C, 55.10; H, 4.62; N, 14.83; S, 16.97; Found: C, 54.84; H, 5.24; N,
14.47; S, 16.10; IR (KBr, cm−1): ν = 3053 (Ar H), 2977, 2923 (C H), 1647 (C O),
1
1577 (C C). H NMR (499.74 MHz, CDCl3): δ = 8.4, 8.3 (d, 9H, CHarom), 4.2 (m,
2H, O CH2-), 3.4, 3.4, 3.3, 3.0 (m, 12H, CH2-), 1.3 ppm (m, 3H, CH3 ). 13C
NMR (125.66 MHz, CDCl3): δ = 14.5 ( CH3), 32.0, (S CH2), 34.6 (SCH2 CH2), 68.4
(O CH2), 129.1 (C S), 141.4, 142.7, 143.7, 145.3, 153.8 (N CHarom, Carom), 155.7
(CO C O), 173.2, 177.7 (C O) ppm. MS (m/z, (relative abundance,%)): 567 (M+H+,
100).
2-(2-ethylhexyloxy)-3,5,6-Trichlorocyclohexa-2,5-diene-1,4-dione (16): Com-
pound 16 was synthesized from the reaction of 1 (1 g, 4.066 mmol) with 15 (1.27 mL,
8.1 mmol) according to the general procedure 2.
Orange solid; Yield: 0.88 g (63%); M.p.: 82–83◦C; Rf = 0.5 (CHCl3/petroleum ether
1:2); Anal. Calcd. for C14H17Cl3O5 :C, 49.51; H, 5.05; Found: C, 50.06; H, 6.02; IR (KBr,
1
cm−1): ν = 2955, 2929, 2872 (C H), 1685, 1660 (C O), 1615, 1577 (C C). H NMR
(499.74 MHz, CDCl3): δ = 4.2 (s, 2H, O CH2), 1.6, 1.4, 1.3, 1.2 (m, 9H, CH2), 0.8 (m,
6H, CH3) ppm; 13C NMR (125.66 MHz, CDCl3): δ = 10.0, 13.0 ( CH3), 21.9, 22.4,
27.9, 28.9 ( CH2-), 39.5 (O CH2), 124.4, 137.6, 139.4 (C Cl), 153.8 ( C O), 170.8,
171.8 (C O) ppm; MS (m/z, (relative abundance,%)): 338 (M−, 100).
2,3,5-Trichloro-6-(pyridine-3-yloxy)cyclohexa-2,5-diene-1,4-dione (18): Com-
pound 18 was synthesized from the reaction of 1 (1 g, 4.066 mmol) with 17 (0.77 g,
4.066 mmol) according to the general procedure 2.

THIO/ALKOXY-SUBSTITUTED BENZOQUINONE DERIVATIVES
501
Brown solid; Yield: 0.08 g (6%); M.p.: 310–311◦C; Rf = 0.6 (ethylacetate/petroleum
ether 1:1); Anal. Calcd. for C11H4Cl3NO3: C, 43.39; H, 1.32; N, 4.60; Found: C, 43.70; H,
2.02; N, 3.87; IR (KBr, cm−1): ν = 3059 (Ar H) 2923, 2851 (C H), 1689 (C O), 1569
(C C). 1H NMR (499.74 MHz, CDCl3): δ = 7.3 (m, 2H, CH), 8.38 (dd, J = 4.8 Hz, J =
3.4 Hz, 1H, CH N), 8.32 (d, J = 2.9 Hz, 1H, OC CH); 13C NMR (125.66 MHz, CDCl3):
123.6, 123.8, 130.2 (C Cl), 137.6, 138.5, 139.9, 144.4, 149.8 (Carom), 151.6 (OC O),
169.9, 170.27 (C O) ppm. MS (m/z, (relative abundance,%)): 303 (M−, 100).
2-(1H-1,2,4-triazol-3-ylthio)-3,5,6-Trichlorocyclohexa-2,5-diene-1,4-dione (20):
Compound 20 was synthesized from the reaction of 1 (1 g, 4.066 mmol) with 19 (0.82 g,
4.066 mmol) according to the general procedure 2.
Brown solid; Yield: 0.06 g (4%); M.p.: 208–209◦C; Rf = 0.72 (ethylacetate/petroleum
ether 1:1); Anal. Calcd. for C8H2Cl3N3O2S: C, 30.94; H, 0.65; N, 13.53; S, 10.33; Found:
C, 31.02; H, 0.46; N, 13.79; S, 10.37; IR (KBr, cm−1): ν = 3043 (Ar H) 2920, 2847
1
(C H), 1688 (C O), 1568 (C C). H NMR (499.74 MHz, CDCl3): 8.32 (dd, J =
4.9 Hz, J = 4.4 Hz, 1H, NH), 7.3 (m, 1H, CH) ppm.13C NMR (125.66 MHz, CDCl3):
125.1, 139.0(C Cl), 145.8 (N C N), 151.2 (SC N), 152.9 (CO CS), 170.9, 171.9 ppm
(C O); MS (m/z, (relative abundance,%)): 308 (M+, 100).
2,5-bis(4-methyl-oxo-2H-chromen-7-ylthio)-3,6-Dichlorocyclohexa-2,5-diene-
1,4-dione (22): Compound 22 was synthesized from the reaction of 1 (1 g, 4.066 mmol)
with 21 (0.78 g, 4.06 mmol) according to the general procedure 3.
Red solid; Yield: 0.11 g (10%); Rf = 0.35 with CHCl3 as an eluent; Anal. Calcd. for
C26H14Cl2O6S2: C, 56.02; H, 2.52; S, 11.50; Found C, 56.25; H, 2.22; S; IR (KBr, cm−1):
2960, 2923, 2853 (C H), 1719 (ester C O), 1673 (quinone C O), 1529 (C C); 1H NMR
(499.74 MHz, CDCl3): δ 1.1 (s, 6H, CH3), 6.1 (s, 1H, CHvin), 7.2–7.6 (m, 6H, Harom);
13C NMR (125.66 MHz, CDCl3): δ = 29.9 ( CH3), 125.4, 126.0, 141.0, 142.0, 151.5,
152.0, 153.8, 154.2, 160.0, 160.3 (CHarom, Carom, lactone C O); 171.70 (quinone C O);
MS (m/z, (relative abundance,%)): 556 (M−, 100).
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