A simple and versatile protocol for the preparation of functionalized heterocycles utilizing 4-benzoyl-5-phenylamino-2,3-dihydrothiophene-2,3-dione

Article abstract of DOI:10.1080/17415993.2015.1074687

The reaction of ethyl benzoylpyruvate with phenyl isothiocyanate in alkaline medium yields 4-benzoyl-5-phenylamino-2,3-dihydrothiophene-2,3-dione (1). Reaction of the intermediate 1 with primary aromatic amines such as aniline derivatives, benzidine and s

Full text of DOI:10.1080/17415993.2015.1074687

Journal of Sulfur Chemistry
ISSN: 1741-5993 (Print) 1741-6000 (Online) Journal homepage: http://www.tandfonline.com/loi/gsrp20
A simple and versatile protocol for the preparation
of functionalized heterocycles utilizing 4-
benzoyl-5-phenylamino-2,3-dihydrothiophene-2,3-
dione
Hassan Kabirifard, Samira Ghahremani & Anita Afsharpoor
To cite this article: Hassan Kabirifard, Samira Ghahremani & Anita Afsharpoor (2015): A
simple and versatile protocol for the preparation of functionalized heterocycles utilizing 4-
benzoyl-5-phenylamino-2,3-dihydrothiophene-2,3-dione, Journal of Sulfur Chemistry, DOI:
10.1080/17415993.2015.1074687
To link to this article: http://dx.doi.org/10.1080/17415993.2015.1074687
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Date: 10 September 2015, At: 12:07

Journal of Sulfur Chemistry, 2015
http://dx.doi.org/10.1080/17415993.2015.1074687
A simple and versatile protocol for the preparation of
functionalized heterocycles utilizing
4-benzoyl-5-phenylamino-2,3-dihydrothiophene-2,3-dione
Hassan Kabirifard∗ , Samira Ghahremani and Anita Afsharpoor
Department of Chemistry, Islamic Azad University, North Tehran Branch, Tehran, Iran
(Received 25 February 2015; accepted 15 July 2015)
The reaction of ethyl benzoylpyruvate with phenyl isothiocyanate in alkaline medium yields
4-benzoyl-5-phenylamino-2,3-dihydrothiophene-2,3-dione (1). Reaction of the intermediate 1 with
primary aromatic amines such as aniline derivatives, benzidine and secondary aliphatic amines,
namely diethylamine, piperidine, morpholine and piperazine afforded the corresponding thiophene
2a–2g and amide 3a–3d derivatives. Compound 1 reacts with N,Nꢀ- and N,O-dinucleophiles such
as 1,2-diaminoalkanes, 2-aminoethanol, 1-aminoguanidine, guanidine, urea, 1,2-phenylenediamine and
2-amino-4-methylphenol to form the heterocylic compounds 4–10.
Ph
Ph
N
S
N
S
H
O
O
Ph
Ph
NR1R2
N
O
O
O
Ar
H
H
ArNH2
HNR1R2
Ph
N
S
H
O
Ph
NH2
NH2
R1
R2
NH2
XH
H
Ph
N
Ph
N
N
S
H
O
S
O
H
O
N
O
H
O
XH
Ph
N
Ph
O
NH
NH
R2
R1
H2N
H2NHN
NH2
NH2
Ph
N
S
H
Ph
N
O
Ph
S
H
H
N
O
N
H
O
N
Ph
N
H
NH
O
N
NH2
H
Keywords: 4-Benzoyl-5-phenylamino-2; 3-dihydrothiophene-2; 3-dione; 2-Butenamide; 1; 2; 4-Triazin-
5-one; Imidazolidine-4-one; Quinoxalin-2-one
*Corresponding author. Email: h_kabirifard@iau-tnb.ac.ir
© 2015 Taylor & Francis

2
H. Kabirifard et al.
Ph
N
O
1
5
S
H
O
Ph
KOH, DMF
r. t., 24 h
2
Ph
N
C
S
+
OEt
O
4
O
3
O
H
Ph
O
1
Scheme 1. Preparation of 4-benzoyl-5-phenylamino-2,3-dihydrothiophene-2,3-dione (1).
1. Introduction
4-Acylated-5-substituted furan-2,3-dione,[1] 1H-pyrrole-2,3-dione [2–5] and thiophene-2,3-
dione [6–8] are versatile and convenient intermediates for the synthesis of a wide variety of
substituted heterocyclic compounds. This versatility is a result of the qualitative differences
between the α,β-unsaturated double bond and the three-carbonyl functionalities that allow
regioselective functionalization and provide a rich cornucopia of products. Herein, we wish to
report the synthesis of 4-benzoyl-5-phenylamino-2,3-dihydrothiophene-2,3-dione (1) as a new
electrophilic 2,3-dione, derived from the addition of ethyl benzoylpyruvate to phenyl isoth-
iocyanate and KOH in DMF with stirring at room temperature (Scheme 1). We then report
the interaction of the compound 1 with aromatic and aliphatic amines that lead to thiophene,
amide, 1,2,4-triazine, imidazole and quinoxaline that are potential skeletons of important hetero-
cylic and heteroacyclic compounds (Scheme 3,5). We find that the reactions of intermediate
(1) toward a range of nitrogen nucleophiles present an interesting dichotomy between reac-
tions that form sulfur heterocycles and those that form thioamides after ring opening of a cyclic
thioester.
2. Results and discussion
2.1. Synthesis of 4-benzoyl-5-phenylamino-2,3-dihydrothiophene-2,3-dione (1)
The acylation of 3-oxo-N-phenyl-3-alkyl/aryl-propanethioamides by oxalyl chloride at the S
atom and the active methylene group, in aprotic solvents in the temperature range from
−40° to +20°, results in the formation of 4-benzoyl-5-phenylamino-2,3-dihydrothiophene-2,3-
diones.[9] The reaction of benzoylpyruvate and phenyl isothiocyanate in the presence of KOH in
DMF at room temperature produced 4-benzoyl-5-phenylamino-2,3-dihydrothiophene-2,3-dione
(1) in good yield after purification (Scheme 1).
1
The structure of 1 was confirmed by IR, H NMR and 13C NMR spectral data, based on
the structural analogy of similar compounds.[9] The IR spectrum showed absorption bands at
3062, 1760, 1716, 1628, 1583 and 1542 cm−1 attributable to the aromatic CH, thioesteric C O,
=
3
=
=
=
C
=
O, ketonic C O, C C and NH functions, respectively. The low frequency of the ketone
=
C O stretching absorption is probably the result of the conjugation of the C C bond and partic-
ipation of the C O group in an intramolecular hydrogen bond with the amino group of enamine
fragment. The C NMR spectrum of 1 revealed four signals at δ 107.32 ( C–COPh), 159.24
( C–NHPh), 174.83 (C O, thioester) and 182.97 (C O) ppm due to the carbons of the thio-
phene, besides eight signals at δ 127.93–134.29 ppm attributable to the aromatic carbons and a
signal at δ 200.07 ppm for the ketonic carbonyl carbon were identified.
=
13
=
3
=
=
=
Mechanistically, the reaction starts with the formation of an intermediate from reaction
of benzoylpyruvate and phenyl isothiocyanate. Since S-acylation is thermodynamically less

Journal of Sulfur Chemistry
3
O
S
S
N
O
N
O
Ph
Ph
Ph
Ph
O
O
Ph
S
+
Ph
N C
OEt
OEt
OEt
O
O
H
O
O
OH
Ph
N
Ph
N
Ph
N
Ph
S
N
O
OEt
S
S
S
-EtO
H
O
O
O
O
O
O
Ph
Ph
O
O
O
O
Ph
Ph
O
H
1
Scheme 2. Proposed mechanism for the formation of compound 1.
favorable than N-acylation,[9] S atom oxalylation requires aprotic solvent (DMF), strong base
(KOH) and ambient temperature under kinetically controlled conditions to yield product 1
(Scheme 2).
2.2. Reactions of the compound 1 with N-nucleophiles
4-Benzoyl-5-phenylamino-2,3-dihydrothiophene-2,3-dione (1) has been found to be an
especially important starting material or intermediate for the synthesis of various sulfur,
nitrogen-containing heterocyclic and heteroacyclic compounds. Treatment of 1 with primary
aromatic amines in boiling absolute ethanol yields the corresponding 3-arylamino-4-benzoyl-
5-phenylimino-2,5-dihydrothiophene-2-ones (2a–2e) and 1,4-bis(4-benzoyl-5-phenylimino-2-
oxo-2,5-dihydrothiophene-3-ylamino)benzene (2f), while with benzidine in a 1:0.5 ratio
it afforded 4,4ꢀ-bis(4-benzoyl-5-phenylimino-2-oxo-2,5-dihydrothiophene-3-ylamino)biphenyl
(2g) (Scheme 3). Interaction of 1 with secondary aliphatic amines in boiling absolute ethanol
afforded the corresponding N,N-dialkyl 2-hydroxy-4-oxo-4-phenyl-3-N-phenylthiocarbamoyl-
2-butenamides (3a–3c), while with piperazine in a 1:0.5 ratio it afforded 1,4-bis(2-hydroxy-4-
oxo-4-phenyl-3-N-phenylthiocarbamoyl-2-butenoyl)piperazine (3d) (Scheme 3). In the reaction
of intermediate 1 and 1,4-phenylenediamine with 1:1 or 1:0.5 ratio, both 2e and 2f are produced.
However, in the reactions of 1 with each of benzidine and piperazine, whether the ratio is 1:1 or
1:0.5, only 2g and 3d are afforded.
1
The structures of 2a–2g and 3a–3d were confirmed by IR, H NMR and 13C NMR spec-
troscopic data. In the IR and 13C NMR spectra of products 2a–2g the absorptions of carbonyl
13
=
group (C–3) were absent. IR and C NMR absorptions of the C N group in 2a–2g are found
at 1620–1606 cm−1 and δ 164.48–165.26 ppm, respectively. The structural analogy of 3a–3d
can easily be seen from their IR and 13C NMR spectra. Absorption bands of enol OH, amide
=
=
C O and thioamide C–N, NH, C S, groups at 3078–3030, 1747–1729, 1567–1561, 1404–1375
and 1136–1129 cm−1, respectively, are structural characteristics. Their 13C NMR spectra also
revealed signals at δ 163.75–166.07, 173.50–174.46 and 189.73–192.91 ppm due to the carbons
=
=
=
of the C–OH, amide C O and thioamide C S.
These results show that nucleophilic attack of primary aromatic amines occur at car-
bonyl group (C–3) and secondary aliphatic amines at the thioesteric carboxyl group (C–2)
of the thiophenedione ring (1), due to the extremely high reactivity of the carbonyl group
(C–3) and the inductive effect of the alkyl groups (see Scheme 4). The weak reactiv-
ity of the ketone that is not part of the ring is probably the result of the fact that it

4
H. Kabirifard et al.
Ph
N
S
a; Ar=C6H5
ArNH2
b; Ar=4-C6H4CH3
c; Ar=4-C6H4NO2
d; Ar=4-C6H4OH
O
Ph
N
O
Ar
H
2a-d
Ph
Ph
N
S
N
S
NH2
H2N
O
O
+
Ph
Ph
N
O
N
O
H
H
H
NH2
O
N
S
Ph
O
Ph
N
N
S
Ph
NH2
0.5 H2N
O
Ph
N
O
H
EtOH
1
H
O
N
S
Ph
O
N
Ph
Ph
N
S
HNR1R2
H
O
a; R1=R2=CH2CH3
b; R1+R2=(CH2)5
c; R1+R2=(CH2)2O(CH2)2
Ph
NR1R2
O
O
H
3a-c
Ph
N
0.5
NH
HN
S
H
O
H
Ph
O
O
N
N
O
O
Ph
H
H
O
N
S
3d
Ph
Scheme 3. Reactions 1 with N-nucleophiles.
=
is an aromatic ketone and that the C O group participates in an intramolecular hydro-
gen bond with the amino group. The reaction pathways and regioselectivity depend on the
N-nucleophile.

Journal of Sulfur Chemistry
5
Ph
N
Ph
N
Ph
S
N
S
H
O
S
H
O
-H2O
O
NH2Ar
+
O
O
Ph
Ph
O
N
O
N
Ph
Ar
Ar
H
1
2
Ph
N
Ph
Ph
N
S
S
N
SH
O
H
H
O
H
H
O
O
O
O
+
HNR1R2
O
NR1R2
NR1R2
Ph
O
O
Ph
Ph
1
Ph
N
Ph
S
N
S
H
H
O
O
O
Ph
NR1R2
NR1R2
O
Ph
O
O
H
3
Scheme 4. Formation of 3-arylamino-2,5-dihydrothiophene-2-ones (2) and N,N-dialkyl 2-butenamide (3).
2.3. Reactions of the compound 1 with N,Nꢀ- and N,O-dinucleophiles
Reaction of 1 with 1,2-diaminoalkanes, 2-aminoethanol and 1-aminoguanidine in boiling abso-
lute ethanol gave the corresponding 3-(2ꢀ-amino(or hydroxy)alkylimino)-2,3-dihydrothiophene-
2-ones (4a–4c) and 3-amino-1,4,5,6-tetrahydro-1,2,4-triazin-5-one (5) derivatives, respectively
(Scheme 5). Also, 1 was reacted with guanidine, urea, 1,2-phenylenediamine and 2-amino-
4-methylphenol in boiling glacial acetic acid to give the substituted 2-iminoimidazolidine-
4-one (6), 3-amino-2,5-dihydrothiophene-2-one (7), imidazolidine-2,4-dione (8), 1,2,3,4-
tetrahydroquinoxalin-2-one (9) and 3-arylamino-2,5-dihydrothiophene-2-one (10) derivatives,
respectively (Scheme 5). While compound 1 reacts with 1-aminoguanidine, guanidine, urea and
1,2-phenylenediamine, to give functionalized 1,2,4-triazin-5-one (5), imidazolidine-4-one (6),
imidazolidine-2,4-dione (8) and quinoxalin-2-one (9) derivatives, the reaction between 1 and
1,2-diaminoalkanes, 2-aminoethanol and 2-aminophenol did not lead to the formation of the
corresponding pyridazine, 1,4-oxazine and 1,4-benzoxazine derivatives.
Structures 4–10 were assigned on the basis of IR, 1H NMR and 13C NMR spectral data. In the
IR and 13C NMR spectra of 4a–4c, 7 and 10, the absorptions due to carbonyl group (C–3) were
absent. IR and 13C NMR absorptions of the C N group in 4a–4c, 7 and 10 are found at 1620–
=
1590 cm−1 and δ 163.42–168.56 ppm, respectively. The IR spectra of 5, 6, 8 and 9 revealed the
=
=
characteristic absorption bands of amide C O and thioamide C–N, NH, C S, groups at 1748–
1716, 1539–1510, 1396–1374 and 1136–1133 cm−1, respectively. Their 13C NMR spectra also
showed signals at δ 167.41–173.45 and 188.25–189.66 ppm due to the carbons of the amide
=
=
C O and thioamide C S.
Carbon atoms C–2, C–3 and C–5 in compound 1 are electrophilic sites that can
exhibit different reactivities depending on the structures of the nucleophiles and reaction
conditions.[10] Indeed, while the N,Nꢀ-dinucleophiles such as 1-aminoguanidine, guanidine, urea

6
H. Kabirifard et al.
Ph
N
R1
R2
NH2
XH
S
H
O
O
a; X=NH, R1=R2=H
b; X=NH, R1+R2=(CH2)4
c; X=O, R1=R2=H
XH
Ph
N
R2
R1
EtOH
4a-c
Ph
N
NH
S
H
H2NHN
NH2
O
N
H
Ph
N
O
N
NH2
H
5
NH
Ph
N
S
H2N
NH2
H
1
O
Ph
H
N
O
N
H
NH
6
Ph
Ph
O
N
N
S
S
H2N
NH2
H
O
+
O
O
Ph
H
N
O
NH2
Ph
O
N
H
AcOH
8
NH2
NH2
Ph
N
S
H
O
H
Ph
N
O
N
H
9
NH2
Ph
H3C
N
S
OH
O
Ph
CH3
N
O
H
HO
Scheme 5. Reactions 1 with N,Nꢀ- and N,O-dinucleophiles.

Journal of Sulfur Chemistry
7
Ph
N
Ph
N
Ph
N
S
O
S
S
H
O
-H2O
H
O
H
path a
+
+
H2O
a
O
O
O
H2N
NH2
O
b
H
O
NH2
Ph
N
Ph
O
Ph
-NH3
N
H
path b
1
O
NH2
O
Ph
N
Ph
N
Ph
SH
N
S
H
O
N
O
H
O
S
O
H
O
H
H
O
N
NH
O
Ph
O
Ph
N
Ph
O
N
O
H
-CO2
Ph
O
Ph
N
Ph
N
Ph
S
S
H
O
H
N
O
N
O
S
S
H
Ph
H
H
O
N
O
N
Ph
O
O
N
Ph
O
N
H
NH
Ph
NH
O
H
7
8
Ph
Ph
Ph
N
N
H2N
S
N
S
S
-H2O
H
H
O
H
O
+
O
O
O
H
O
H2N
NH2
NH
Ph
Ph
N
Ph
O
N
1
Ph
Ph
N
Ph
N
SH
N
N
S
S
H
O
H
H
O
O
O
H
H
H
Ph
O
N
N
N
O
Ph
N
N
Ph
H
9
Scheme 6. Formation of 3-amino-2,5-dihydrothiophene-2-one (7), imidazolidine-2,4-dione (8) and 1,2,3,4-tetrahydro-
quinoxalin-2-one (9).
and 1,2-phenylenediamine [6,7] cyclize by nucleophilic attack at the α-ketothioesteric fragment
(C–2 and C–3) of 1 (see Scheme 6), 1,2-diaminoalkanes, 2-aminoethanol and 2-aminophenol
react via a nucleophilic attack of the NH2 group at the carbonyl group (C–3) of the thiophene-
dione 1.
3. Conclusion
In conclusion, we have described a convenient route for the synthesis of functional-
ized 3-arylamino(or 3-alkylimino)thiophene-2-ones, N,N-dialkyl 2-butenamides, 3-amino-1,
4,5,6-tetrahydro-1,2,4-triazin-5-one, 2-iminoimidazolidine-4-one, imidazolidine-2,4-dione and

8
H. Kabirifard et al.
1,2,3,4-tetrahydroquinoxalin-2-one
from
4-benzoyl-5-phenylamino-2,3-dihydrothiop
hene-2,3-dione with N-nucleophiles, N,Nꢀ- and N,O-dinucleophiles. The advantage of the present
procedure is that the reaction is performed under neutral conditions by simple mixing of the
starting materials.
4. Experimental
4.1. General
The chemicals were purchased from Merck and used without further purification. Melting points
were measured with an Electrothermal 9100 apparatus and are uncorrected. Elemental analyses
were performed using a Heraeus CHN-O-Rapid analyzer. These results agree favorably with the
calculated values. Infrared (IR) spectra were measured from KBr disk using a Thermo Nicolet
8700 FT–IR spectrometer and frequencies were reported in cm−1. 1H NMR and 13C NMR spectra
were recorded on a Bruker DRX-300 AVANCE at 300 and 75 MHz instrument using TMS as
internal standard and DMSO-d6 or CDCl3 as solvent. Chemical shifts and coupling constants
were reported in ppm and Hz, respectively. Thin-layer chromatography (TLC) was performed
on ‘Silufol-UV 254’ plates. Mass spectra were obtained by using an Agilent HP 5973 mass
spectrometer operating at an ionization potential of 70 eV.
4.2. Material
Ethyl 2,4-dioxo-4-phenylbutanoate was prepared from 10 mmol of diethyl oxalate and 10 mmol
of acetophenone in the presence of 10 mmol of sodium ethoxide using 30 mL of ethanol as the
solvent.[1]
4.3. Synthesis of 4-benzoyl-5-phenylamino-2,3-dihydrothiophene-2,3-dione (1)
To a cold suspension of KOH (0.56 g, 10 mmol), in DMF (20 mL) was added the benzoylpyru-
vate (2.20 g, 10 mmol), followed by phenyl isothiocyanate (1.35 g, 10 mmol). The mixture was
stirred 24 h at room temperature and then poured onto ice-cold water. Acidification using 1 M
HCl (25 mL) until the medium became acidic gave solid product 1. The resulting precipitate was
filtered off, washed well with water, dried and crystallized from 2-propanol to give compound
1.[11]
Yellow crystal; yield: 2.41 g (78%); m.p.: 200–202°C (Lit [9]: 191–193°C). IR (KBr):
3
=
=
=
v¯ = 3062 (CH, aromatic), 1760 (C O, thioester), 1716 (C O), 1602 (C O, ketone), 1583
−1
3
=
(C C) cm
.
1H NMR (CDCl3): δ = 7.35 (2H, d, JHH = 7.2 Hz, 2CHortho of Ph-NH),
7.54–7.62 (5H, m, 2Ph), 7.71 (1H, t, 3JHH = 7.4 Hz, CHpara of Ph-CO), 7.91 (2H, d, 3JHH = 7.4
13
=
Hz, 2CHortho of Ph-CO), 15.28 (1H, br.s, NH). C NMR (CDCl3): δ = 107.32 ( C–COPh),
127.93, 128.25, 129.59, 129.93, 129.97, 131.15, 131.79 (11C, 2Ph), 134.29 (Cipso of Ph-NH),
3
=
=
=
=
159.24 ( C–NHPh), 174.83 (C O, thioester), 182.97 (C O), 200.07 (C O, ketone) ppm.
Anal. Calcd for C17H11NO3S (309.34): C, 66.01%; H, 3.58%; N, 4.53%; found: C, 65.80%; H,
3.59%; N, 4.63%.
4.4. Reactions of the compound 1 with N-nucleophiles: general procedure
A mixture of 1 (0.309 g, 1.0 mmol) and either aniline derivatives (1.0 mmol), benzidine (0.092
g, 0.5 mmol), dialkyl amines (1.0 mmol) or piperazine (0.043 g, 0.5 mmol), in absolute ethanol
(20 mL) was refluxed for 1–3 h. The progress of the reaction was monitored by TLC (eluent

Journal of Sulfur Chemistry
9
AcOEt/hexane 2:1). The solid that was separated in each case was filtered off and was crystal-
lized from a suitable solvent (ethanol or 2-propanol) to give 2a–2d, 2g and 3a–3d, respectively.
The residue obtained from the reaction 1 and 1,4-phenylenediamine was separated by silica gel
column chromatography (Merck 230–400 mesh) using AcOEt/hexane (1:4) as eluent to give 2e
and 2f. The purification was done by recrystallization of 2-propanol.
4.4.1. 4-Benzoyl-3-phenylamino-5-phenylimino-2,5-dihydrothiophene-2-one (2a)
Orange powder; yield: 0.27 g (71%); m.p.: 248–250°C. IR (KBr): v¯ = 3440, 3281 (NH), 1740
(C O, thioester), 1665 (C O, ketone), 1610 (C N), 1566 (C C), 1511 (NH) cm−1. 1H NMR
=
=
=
=
3
(DMSO-d6): δ = 6.99 (2H, d, JHH = 7.6 Hz, 2CHortho of Ph-NH), 7.16–7.52 (11H, m, 3Ph),
3
7.55 (2H, d, JHH = 6.7 Hz, 2CHortho of Ph-CO), 13.46 (1H, br.s, NH). 13C NMR (DMSO-
=
d6): δ = 104.50 ( C–COPh), 125.15, 125.20, 127.26, 128.25, 128.86, 129.00, 129.03, 129.12,
=
=
130.21, 130.52 (16C, 3Ph), 133.54 (Cipso of Ph-NH), 135.97 (Cipso of Ph-N C), 159.93 ( C–
=
=
=
NH), 164.88 (C N), 175.50 (C O, thioester), 197.54 (C O, ketone) ppm. EI–MS: m/z (%) =
386 (M·+ 2, 3), 384 (M·+, 29), 295 (94), 236 (20), 220 (19), 204 (14), 193 (33), 180 (26), 91
+
(9), 77 (100), 65 (12), 51 (35). Anal. Calcd for C23H16N2O2S (384.45): C, 71.85%; H, 4.19%;
N, 7.29%; found: C, 71.53%; H, 4.05%; N, 7.13%.
4.4.2. 4-Benzoyl-3-(4-methylphenylamino)-5-phenylimino-2,5-dihydrothiophene-2-one (2b)
Orange powder; yield: 0.27 g (68%); m.p.: 178–180°C. IR (KBr): v¯ = 3443, 3264 (NH), 2919
=
=
=
=
(CH, aliphatic), 1739 (C O, thioester), 1653 (C O, ketone), 1620 (C N), 1575 (C C), 1520
(NH) cm−1. 1H NMR (CDCl3): δ = 2.30 (3H, s, CH3), 6.77 (2H, d, 3JHH = 8.0 Hz, 2CHortho of
Ph-NH), 7.03 (2H, d, 3JHH = 8.0 Hz, 2CHortho of Ph-CH3), 7.31–7.55 (8H, m, 2Ph), 7.58 (2H, d,
3JHH = 6.8 Hz, 2CHortho of Ph-CO), 13.95 (1H, br.s, NH). 13C NMR (CDCl3): δ = 21.00 (CH3),
=
104.43 ( C–COPh), 124.51, 124.60, 128.53, 128.60, 128.64, 129.25, 129.83, 129.95, 130.84,
132.85 (16C, 3Ph), 133.36 (Cipso of Ph-NH), 137.49 (Cipso of Ph-N C), 159.62 ( C–NH),
=
=
=
=
=
165.26 (C N), 175.52 (C O, thioester), 198.26 (C O, ketone) ppm. EI–MS: m/z (%) = 400
(M·+ 2, 7), 398 (M·+, 65), 369 (9), 309 (100), 280 (6), 250 (12), 220 (16), 207 (33), 105 (51),
+
91 (41), 77 (70), 65 (31), 51 (30). Anal. Calcd for C24H18N2O2S (398.48): C, 72.34%; H, 4.55%;
N, 7.03%; found: C, 72.65%; H, 4.36%; N, 7.21%.
4.4.3. 4-Benzoyl-3-(4-nitrophenylamino)-5-phenylimino-2,5-dihydrothiophene-2-one (2c)
=
Orange powder; yield: 0.31 g (72%); m.p.: 161–163°C. IR (KBr): v¯ = 3450 (NH), 1746 (C O,
1
thioester), 1666 (C O, ketone), 1620 (C N), 1554, 1335 (NO2), 1514 (NH) cm−1. H NMR
=
=
3
(CDCl3): δ = 6.97 (2H, d, JHH = 9.0 Hz, 2CHortho of Ph-NH), 7.34–7.59 (8H, m, 2Ph), 7.62
(2H, d, 3JHH = 7.6 Hz, 2CHortho of Ph-CO), 8.10 (2H, d, 3JHH = 9.0 Hz, 2CHortho of Ph-NO2),
13
=
14.15 (1H, br.s, NH). C NMR (CDCl3): δ = 105.10 ( C–COPh), 124.52, 124.83, 128.28,
128.52, 128.76, 129.26, 129.44, 129.58, 131.77 (15C, 3Ph), 132.52 (Cipso of Ph-NH), 142.03
=
=
=
=
(Cipso of Ph-N C), 145.61 (Cipso of Ph-NO2), 159.42 ( C–NH), 164.48 (C N), 175.83 (C O,
·+
·+
=
thioester), 198.16 (C O, ketone) ppm. EI–MS: m/z (%) = 429 (M , 6), 414 (M , 25), 384
(43), 295 (100), 236 (23), 220 (17), 193 (29), 180 (21), 91 (17), 77 (64), 65 (24), 51 (31). Anal.
Calcd for C23H15N3O4S (429.45): C, 64.33%; H, 3.52%; N, 9.78%; found: C, 64.08%; H, 3.68%;
N, 9.69%.
4.4.4. 4-Benzoyl-3-(4-hydroxyphenylamino)-5-phenylimino-2,5-dihydrothiophene-2-one (2d)
Orange powder; yield: 0.26 g (65%); m.p.: 312–314°C. IR (KBr): v¯ = 3431 (NH), 3344 (OH),
=
=
=
=
3045 (CH, aromatic), 1733 (C O, thioester), 1693 (C O, ketone), 1620 (C N), 1576 (C C),

10 H. Kabirifard et al.
1
3
1515 (NH) cm−1. H NMR (DMSO-d6): δ = 6.61 (2H, d, JHH = 7.2 Hz, 2CHortho of Ph-
3
OH), 6.83 (2H, d, JHH = 7.2 Hz, 2CHortho of Ph-NH), 7.36–7.51 (8H, m, 2Ph), 7.55 (2H,
d, JHH = 6.8 Hz, 2CHortho of Ph-CO), 9.74, 13.39 (2H, 2br.s, OH, NH). 13C NMR (DMSO-
3
=
d6): δ = 105.07 ( C–COPh), 123.41, 125.23, 125.84, 127.32, 128.22, 128.51, 128.84, 130.56,
=
130.81, (15C, 3Ph), 133.52 (Cipso of Ph-NH), 135.63 (Cipso of Ph-N C), 149.78 (Cipso of Ph-
=
=
=
=
OH), 159.84 ( C–NH), 165.12 (C N), 175.44 (C O, thioester), 198.25 (C O, ketone) ppm.
EI–MS: m/z (%) = 400 (M·+, 5), 384 (M·+, 42), 295 (100), 236 (26), 220 (28), 193 (33), 180
(23), 91 (9), 77 (81), 65 (11), 51 (30). Anal. Calcd for C23H16N2O3S (400.45): C, 68.98%; H,
4.03%; N, 7.00%; found: C, 69.27%; H, 4.16%; N, 7.24%.
4.4.5. 3-(4-Aminophenylamino)-4-benzoyl-5-phenylimino-2,5-dihydrothiophene-2-one (2e)
Orange powder; yield: 0.18 g (45%); m.p.: 357–359°C. IR (KBr): v¯ = 3438, 3387, 3250 (NH,
−1
=
=
=
=
NH2), 1738 (C O, thioester), 1660 (C O, ketone), 1619 (C N), 1583 (C C), 1520 (NH) cm
.
1H NMR (DMSO-d6): δ = 5.32 (2H, br.s, NH2), 6.35 (2H, d, JHH = 8.8 Hz, 2CHortho of Ph-
3
3
NH2), 6.62 (2H, d, JHH = 8.8 Hz, 2CHortho of Ph-NH), 7.21–7.53 (8H, m, 2Ph), 7.62 (2H, d,
3JHH = 7.6 Hz, 2CHortho of Ph-CO), 13.38 (1H, br.s, NH). 13C NMR (DMSO-d6): δ = 104.85
=
( C–COPh), 123.91, 125.56, 128.61, 128.71, 128.75, 129.22, 129.76, 129.84, 130.69 (15C,
=
3Ph), 133.69 (Cipso of Ph-NH), 136.59 (Cipso of Ph-N C), 139.25 (Cipso of Ph-NH2), 159.75
=
=
=
=
( C–NH), 165.56 (C N), 175.81 (C O, thioester), 198.33 (C O, ketone) ppm. EI–MS: m/z
(%) = 401 (M·+ 2, 5), 399 (M·+, 53), 384 (32), 295 (100), 236 (24), 220 (17), 193 (35), 180
+
(22), 91 (16), 77 (62), 65 (15), 51 (31). Anal. Calcd for C23H17N3O2S (399.46): C, 69.15%; H,
4.29%; N, 10.52%; found: C, 68.79%; H, 4.17%; N, 10.61%.
4.4.6. 1,4-Bis(4-benzoyl-2-oxo-5-phenylimino-2,5-dihydrothiophene-3-ylamino)benzene (2f)
=
Red powder; yield: 0.23 g (33%); m.p.: 256–258°C. IR (KBr): v¯ = 3431 (NH), 1736 (C O,
−1
1H NMR
=
=
=
thioester), 1662 (C O, ketone), 1620 (C N), 1586 (C C), 1518 (NH) cm
.
(DMSO-d6): δ = 6.84 (2(2H), s, 4CHortho of Ph-NH), 7.24–7.46 (2(8H), m, 4Ph), 7.51 (2(2H),
d, JHH = 7.2 Hz, 4CHortho of Ph-CO), 13.26 (2(1H), br.s, 2NH). 13C NMR (DMSO-d6):
3
=
δ = 105.24 (2 C–COPh), 119.56, 124.35, 127.53, 128.64, 128.71, 129.68, 129.93, 132.69
=
=
(26C, 5Ph), 133.45 (2Cipso of Ph-NH), 135.74 (2Cipso of Ph-N C), 159.43 (2 C–NH), 165.·7+8
=
=
=
(2C N), 176.11 (2C O, thioester), 197.86 (2C O, ketone) ppm. EI–MS: m/z (%) = 690 (M ,
3), 295 (57), 236 (18), 220 (23), 204 (18), 193 (36), 180 (23), 91 (12), 77 (100), 65 (19), 51 (29).
Anal. Calcd for C40H26N4O4S2 (690.79): C, 69.55%; H, 3.79%; N, 8.11%; found: C, 69.75%; H,
3.68%; N, 8.26%.
4.4.7. 4,4ꢀ-Bis(4-benzoyl-2-oxo-5-phenylimino-2,5-dihydrothiophene-3-ylamino)biphenyl (2g)
Orange-yellow powder; yield: 0.30 g (78%); m.p.: 328–330°C. IR (KBr): v¯ = 3448 (NH), 3032
=
=
=
=
(CH, aromatic), 1750 (C O, thioester), 1698 (C O, ketone), 1606 (C N), 1588 (C C), 1548
1
3
(NH) cm−1. H NMR (DMSO-d6): δ = 7.01 (2(2H), d, JHH = 8.5 Hz, 4CHortho of Ph-NH),
7.36 (2(2H), d, 3JHH = 8.5 Hz, 4CHmeta of Ph-NH), 7.40–7.58 (2(10H), m, 4Ph), 13.46 (2(1H),
br.s, 2NH). 13C NMR (DMSO-d6): δ = 105.32 (2 C–COPh), 125.31, 127.01, 128.40, 128.83,
=
128.89, 128.99, 129.04, 130.19, 130.71, 133.52 (32C, 6Ph), 135.71 (2Cipso of Ph-NH), 136.84
=
=
=
=
(2Cipso of Ph-N C), 159.90 (2 C–NH), 164.28 (2C N), 175.82 (2C O, thioester), 197.47
·+
=
(2C O, ketone) ppm. EI–MS: m/z (%) = 766 (M , 3), 309 (37), 280 (10), 252 (17), 221 (7),
105 (92), 77 (100), 43 (61). Anal. Calcd for C46H30N4O4S2 (766.88): C, 72.04%; H, 3.94%; N,
7.31%; found: C, 72.28%; H, 4.13%; N, 7.18%.

Journal of Sulfur Chemistry 11
4.4.8. N,N-Diethyl 2-hydroxy-4-oxo-4-phenyl-3-(N-phenylthiocarbamoyl)-2-butenamide (3a)
Red crystal; yield: 0.24 g (63%); m.p.: 186–188°C. IR (KBr): v¯ = 3430 (NH), 3078 (OH, enol),
=
=
=
2853 (CH, aliphatic), 1733 (C O, amide), 1640 (C O, ketone), 1600 (C C), 1566, 1375, 1129
(C–N, NH, C S, thioamide) cm−1. 1H NMR (CDCl3): δ = 1.28 (6H, t, 3JHH = 7.2 Hz, 2CH3),
=
3.29 (4H, q, 3JHH = 7.2 Hz, 2CH2–N), 7.34 (2H, d, 3JHH = 8.0 Hz, 2CHortho of Ph-NH), 7.40–
3
7.53 (6H, m, 2Ph), 7.78 (2H, d, JHH = 7.6 Hz, 2CHortho of Ph-CO), 9.17 (2H, br.s, NH, OH).
13
=
C NMR (CDCl3): δ = 12.11 (2CH3), 43.71 (2CH2), 114.49 ( C–COPh), 127.02, 127.59,
128.51, 128.78, 129.15, 131.28 (1°C, 2Ph), 133.77 (Cipso of Ph-CO), 140.62 (Cipso of Ph-NH),
=
=
=
=
166.07 ( C–OH), 174.46 (C O, amide), 192.91 (C S), 199.22 (C O, ketone) ppm. EI–MS:
m/z (%) = 382 (M·+, 6) 309 (55), 280 (12), 252 (16), 222 (11), 105 (100), 77 (65), 74 (98),
58 (54). Anal. Calcd for C21H22N2O3S (382.48): C, 65.95%; H, 5.80%; N, 7.32%; found: C,
65.73%; H, 5.96%; N, 7.51%.
4.4.9. Piperidino 2-hydroxy-4-oxo-4-phenyl-3-(N-phenylthiocarbamoyl)-2-butenamide (3b)
Red crystal, yield: 0.19 g (49%); m.p. 160–162°C. IR (KBr): v¯ = 3429 (NH), 3030 (OH, enol),
=
=
=
2947 (CH, aliphatic), 1747 (C O, amide), 1638 (C O, ketone), 1595 (C C), 1567, 1375, 1130
(C–N, NH, C S, thioamide) cm−1. 1H NMR (CDCl3): δ = 1.62 (2H, br.s, CH2), 1.78 (4H, br.s,
=
3
2CH2), 3.19 (4H, br.s, 2CH2–N), 7.15 (2H, d, JHH = 7.9 Hz, 2CHortho of Ph-NH), 7.35–7.53
(6H, m, 2Ph), 7.75 (2H, d, JHH = 7.4 Hz, 2CHortho of Ph-CO), 8.75 (2H, br.s, NH, OH). 13C
3
=
NMR (CDCl3): δ = 21.97 (CH2), 22.67 (2CH2), 44.23 (2CH2–N), 113.43 ( C–COPh), 127.07,
127.63, 128.62, 128.75, 129.21, 131.30 (1°C, 2Ph), 133.85 (Cipso of Ph-CO), 141.03 (Cipso of
=
=
=
=
Ph-NH), 165.84 ( C–OH), 175.13 (C O, amide), 189.83 (C S), 198.15 (C O, ketone) ppm.
EI–MS: m/z (%) = 394 (M·+, 17) 309 (48), 280 (23), 252 (12), 221 (10), 105 (100), 86 (81), 77
(67), 70 (61). Anal. Calcd for C22H22N2O3S (394.49): C, 66.98%; H, 5.62%; N, 7.10%; found:
C, 67.22%; H, 5.53%; N, 7.28%.
4.4.10. Morpholino 2-hydroxy-4-oxo-4-phenyl-3-(N-phenylthiocarbamoyl)-2-butenamide (3c)
Orange crystal; yield: 0.21 g (53%); m.p.: 124–126°C. IR (KBr): v¯ = 3430 (NH), 3032 (OH,
=
=
=
enol), 2946 (CH, aliphatic), 1746 (C O, amide), 1640 (C O, ketone), 1593 (C C), 1567,
1
1375, 1136 (C–N, NH, C S, thioamide) cm−1. H NMR (DMSO-d6): δ = 3.09 (4H, br.s,
=
3
2CH2–N), 3.74 (4H, br.s, 2CH2–O), 7.21 (2H, d, JHH = 7.0 Hz, 2CHortho of Ph-NH), 7.36–
3
7.44 (6H, m, 2Ph), 7.62 (2H, d, JHH = 6.9 Hz, 2CHortho of Ph-CO), 8.87 (2H, br.s, NH, OH).
13
=
C NMR (DMSO-d6): δ = 43.27 (2CH2–N), 63.71 (2CH2–O), 113.54 ( C–COPh), 127.34,
127.59, 128.62, 129.45, 129.92, 131.18 (1°C, 2Ph), 135.35 (Cipso of Ph-CO), 141.09 (Cipso of
=
=
=
=
Ph-NH), 163.75 ( C–OH), 173.50 (C O, amide), 189.73 (C S), 197.73 (C O, ketone) ppm.
EI–MS: m/z (%) = 396 (M·+, 13) 309 (59), 281 (18), 252 (24), 221 (14), 105 (100), 88 (91), 77
(68), 72 (52). Anal. Calcd for C21H20N2O4S (396.46): C, 63.62%; H, 5.08%; N, 7.07%; found:
C, 63.28%; H, 5.17%; N, 7.21%.
4.4.11. 1,4-Bis(2-hydroxy-4-oxo-4-phenyl-3-N-phenylthiocarbamoyl-2-butenoyl)piperazine
(3d)
Orange crystal; yield: 0.26 g (74%); m.p.: 235–237°C. IR (KBr): v¯ = 3487 (NH), 2959 (CH,
=
=
=
aliphatic), 1729 (C O, amide), 1627 (C O, ketone), 1589 (C C), 1561, 1404, 1134 (C–N, NH,
=
1
C S, thioamide) cm−1. H NMR (DMSO-d6): δ = 3.31 (8H, br.s, 4CH2–N), 7.24 (2(2H), d,
3JHH = 8.0 Hz, 4CHortho of Ph-NH), 7.37–7.43 (2(6H), m, 4Ph), 7.65 (2(2H), d, 3JHH = 7.5 Hz,

12 H. Kabirifard et al.
4CHortho of Ph-CO), 8.84 (2(2H), br.s, 2NH, 2OH). 13C NMR (DMSO-d6): δ = 40.43 (4CH2–
=
N), 113.13 (2 C–COPh), 127.35, 127.47, 128.20, 129.02, 129.44, 130.80 (2°C, 4Ph), 134.79
=
=
(2Cipso of Ph-CO), 140.58 (2Cipso of Ph-NH), 163.44 (2 C–OH), 173.24 (2C O, amide), 189.51
·+
=
=
(2C S), 197.50 (2C O, ketone) ppm. EI–MS: m/z (%) = 704 (M , 2) 309 (91), 280 (17), 252
(27), 221 (11), 105 (100), 77 (85), 51 (24). Anal. Calcd for C38H32N4O6S2 (704.81): C, 64.76%;
H, 4.58%; N, 7.95%; found: C, 64.51%; H, 4.51%; N, 7.84%.
4.5. Reactions of the compound 1 with N,Nꢀ- and N,O-dinucleophiles
4.5.1. General procedure for the synthesis of compounds (4a–4c and 5)
To a solution of compound 1 (0.309 g, 1.0 mmol) in absolute ethanol (20 mL), 1,2-
diaminoalkanes, 2-aminoethanol (1.0 mmol) and 1-aminoguanidinium hydrogen carbonate
(0.136 g, 1.0 mmol together 0.082 g, 1.0 mmol of AcONa) were added. The reaction mixture was
refluxed for 2–3 h. The progress of the reaction was monitored by TLC (eluent AcOEt/hexane
2:1). The solid that was separated in each case was filtered off and was crystallized from a
suitable solvent (ethanol, 2-propanol) to give 4a–4c and 5, respectively.
4.5.1.1. 3-(2ꢀ-Aminoethylimino)-4-benzoyl-5-phenylamino-2,3-dihydrothiophene-2-one (4a).
Yellow powder; yield: 0.26 g (75%); m.p.: 267–269°C. IR (KBr): v¯ = 3443, 3210 (NH), 2926
−1
=
=
=
(CH, aliphatic), 1733 (C O, thioester), 1627 (C O, ketone), 1610 (C N), 1507 (NH) cm
.
1H NMR (DMSO-d6): δ = 3.75, 4.02 (4H, 2br.s, CH2NH2, CH2N), 7.20 (2H, d, 3JHH = 6.7 Hz,
2CHortho of Ph-NH), 7.38–7.44 (6H, m, 2Ph), 7.47 (2H, d, 3JHH = 7.0 Hz, 2CHortho of Ph-CO),
7.61, 9.84 (3H, 2br.s, NH2, NH). 13C NMR (DMSO-d6): δ = 47.68, 53.76 (CH2NH2, CH2N),
=
103.31 ( C–COPh), 127.88, 128.14, 128.50, 129.14, 129.32, 129.45, 130.31 (11C, 2Ph), 134.89
=
=
=
=
(Cipso of Ph-NH), 164.19 ( C–NH), 166.62 (C N), 174.21 (C O, thioester), 195.47 (C O,
ketone) ppm. EI–MS: m/z (%) = 351 (M·+, 3), 333 (100), 304 (34), 104 (22), 91 (21), 77 (95),
65 (12), 51 (39). Anal. Calcd for C19H17N3O2S (351.42): C, 64.94%; H, 4.88%; N, 11.96%;
found: C, 64.67%; H, 4.73%; N, 11.79%.
4.5.1.2. 3-(2ꢀ-Aminocyclohexylimino)-4-benzoyl-5-phenylamino-2,3-dihydrothiophene-2-one
(4b). Yellow powder; yield: 0.28 g (70%); m.p.: 273–275°C. IR (KBr): v¯ = 3470, 3203 (NH),
=
=
3051 (CH, aromatic), 2937 (CH, aliphatic), 1734 (C O, thioester), 1621 (C O, ketone), 1610
(C N), 1577 (C C), 1516 (NH) cm−1. 1H NMR (CDCl3): δ = 1.45–2.52 (8H, m, 4CH2), 3.42,
3.64 (2H, 2br.m, CHNH2, CHN), 5.39 (2H, br.s, NH2), 7.28 (2H, d, 3JHH = 6.5 Hz, 2CHortho of
Ph-NH), 7.35–7.48 (6H, m, 2Ph), 7.52 (2H, d, 3JHH = 6.8 Hz, 2CHortho of Ph-CO), 10.48 (1H,
br.s, NH). 13C NMR (CDCl3): δ = 23.56, 23.84, 35.19, 37.26 (4CH2), 49.58, 54.16 (CH2NH2,
=
=
=
CH2N), 103.82 ( C–COPh), 127.68, 128.77, 128.89, 129.25, 129.57, 129.92, 130.45 (11C, 2Ph),
134.26 (Cipso of Ph-NH), 163.42 ( C–NH), 167.23 (C N), 175.46 (C O, thioester), 196.75
=
=
=
·+
=
(C O, ketone) ppm. EI–MS: m/z (%) = 405 (M , 3), 387 (100), 346 (27), 331 (19), 104 (25),
91 (7), 77 (50), 51 (16). Anal. Calcd for C23H23N3O2S (405.51): C, 68.12%; H, 5.72%; N,
10.36%; found: C, 67.87%; H, 5.59%; N, 10.57%.
4.5.1.3. 4-Benzoyl-3-(2ꢀ-hydroxyethylimino)-5-phenylamino-2,3-dihydrothiophene-2-one (4c).
Yellow powder; yield: 0.26 g (73%); m.p.: 265–267°C. IR (KBr): v¯ = 3407 (NH, OH), 2945
=
=
=
=
(CH, aliphatic), 1747 (C O, thioester), 1685 (C O, ketone), 1590 (C N), 1575 (C C), 1511
(NH) cm−1. 1H NMR (DMSO-d6): δ = 3.26, 3.50 (4H, 2br.t, 3JHH = 5.0 Hz, CH2N, CH2OH),
5.13 (1H, br.s, OH), 7.29 (2H, d, 3JHH = 7.8 Hz, 2CHortho of Ph-NH), 7.38–7.50 (6H, m, 2Ph),
7.53 (2H, d, JHH = 7.2 Hz, 2CHortho of Ph-CO), 12.15 (1H, br.s, NH). 13C NMR (DMSO-
3
=
d6): δ = 47.23, 59.05 (CH2N, CH2OH), 104.41 ( C–COPh), 127.33, 128.58, 128.67, 128.85,

Journal of Sulfur Chemistry 13
=
=
128.98, 130.07, 130.81 (11C, 2Ph), 133.55 (Cipso of Ph-NH), 160.22 ( C–NH), 167.75 (C N),
·+
=
=
175.38 (C O, thioester), 197.14 (C O, ketone) ppm. EI–MS: m/z (%) = 354 (M 2, 7), 352
+
(M·+, 92), 321 (8), 309 (15), 280 (5), 252 (6), 220 (19), 104 (83), 91 (16), 77 (100), 51 (46).
Anal. Calcd for C19H16N2O3S (352.41): C, 64.76%; H, 4.58%; N, 7.95%; found: C, 65.11%; H,
4.75%; N, 8.16%.
4.5.1.4. 3-Amino-6-(benzoyl-N-phenylthiocarbamoylmethylene)-1,4,5,6-tetrahydro-1,2,4-tria-
zin-5-one (5). Orange powder; yield: 0.28 g (78%); m.p.: 240–242°C. IR (KBr): v¯ = 3410,
=
=
=
3226, 3165 (NH, NH2), 1726 (C O, amide), 1653 (C O, ketone), 1590 (C C), 1540 (NH),
1
1510, 1375, 1136 (C–N, NH, C S, thioamide) cm−1. H NMR (DMSO-d6): δ = 4.63, 6.75
=
3
(3H, 2br.s, NH2, NH), 7.18 (2H, d, JHH = 7.6 Hz, 2CHortho of Ph-NH), 7.29–7.42 (6H, m,
2Ph), 7.59 (2H, d, 3JHH = 6.9 Hz, 2CHortho of Ph-CO), 8.57, 12.15 (2H, 2br.s, 2NH). 13C NMR
=
(DMSO-d6): δ = 113.53 ( C–COPh), 127.86, 127.91, 128.61, 129.44, 129.92, 131.15 (1°C,
=
=
2Ph), 135.38 (Cipso of Ph-CO), 141.11 (Cipso of Ph-NH), 159.01 ( C–NH), 163.72 (N C–NH·2+),
=
=
=
173.45 (C O, amide), 189.66 (C S), 197.66 (C O, ketone) ppm. EI–MS: m/z (%) = 365 (M ,
5), 332 (22), 309 (10), 285 (11), 252 (6), 220 (5), 129 (16), 118 (98), 105 (99), 77 (100), 65 (38),
51 (65). Anal. Calcd for C18H15N5O2S (365.41): C, 59.16%; H, 4.14%; N, 19.17%; found: C,
59.39%; H, 4.06%; N, 19.33%.
4.5.2. General procedure for the synthesis of compounds (6–10)
To a solution of compound 1 (0.309 g, 1.0 mmol) in glacial acetic acid (20 mL), guanidinium car-
bonate (0.180 g, 1.0 mmol together 0.082 g, 1.0 mmol of AcONa), urea, 1,2-phenylenediamine
and 2-amino-4-methylphenol (1.0 mmol) was added. The reaction mixture was refluxed for 2–4
h. The progress of the reaction was monitored by TLC (eluent AcOEt/hexane 2:1). The sol-
vent was removed under reduced pressure, and the resulting residue was crystallized from a
suitable solvent (ethanol, 2-propanol) to give 6, 9 and 10, respectively. The residue obtained
from the reaction 1 and urea was separated by silica gel column chromatography (Merck 230–
400 mesh) using AcOEt/hexane (1:4) as eluent to give 7 and 8. The purification was done by
recrystallization of ethanol.
4.5.2.1. 5-(Benzoyl-N-phenylthiocarbamoylmethylene)-2-iminoimidazolidine-4-one (6).
Orange powder; yield: 0.24 g (68%); m.p.: 214–216°C. IR (KBr): v¯ = 3454, 3400, 3116 (NH),
=
=
=
1716 (C O, amide), 1645 (C O, ketone), 1595 (C C), 1575 (NH), 1532, 1396, 1136 (C–
1
N, NH, C S, thioamide) cm−1. H NMR (DMSO-d6): δ = 6.92 (4H, br.s, 4NH), 7.21 (2H,
=
3
3
d, JHH = 7.2 Hz, 2CHortho of Ph-NH), 7.33–7.45 (6H, m, 2Ph), 7.62 (2H, d, JHH = 7.6 Hz,
13
=
2CHortho of Ph-CO). C NMR (DMSO-d6): δ = 113.04 ( C–COPh), 127.35, 127.41, 128.10,
128.96, 129.45, 130.63 (1°C, 2Ph), 134.91 (Cipso of Ph-CO), 140.65 (Cipso of Ph-NH), 158.90
=
=
=
=
=
( C–NH), 163.21 (N C–NH), 173.00 (C O, amide), 189.14 (C S), 197.16 (C O, ketone)
ppm. EI–MS: m/z (%) = 350 (M·+, 2), 317 (4), 309 (65), 281 (13), 252 (6), 220 (28), 105 (24),
77 (22), 57 (100). Anal. Calcd for C18H14N4O2S (350.39): C, 61.70%; H, 4.03%; N, 15.99%;
found: C, 62.03%; H, 4.21%; N, 16.18%.
4.5.2.2. 3-Amino-4-benzoyl-5-phenylimino-2,5-dihydrothiophene-2-one (7) Yellow crystal;
yield: 0.19 g (53%); m.p.: 278–280°C. IR (KBr): v¯ = 3281, 3235 (NH2), 3055 (CH, aromatic),
1748 (C O, thioester), 1675 (C O, ketone), 1618 (C N), 1586 (C C), 1506 (NH) cm−1. 1H
=
=
=
=
3
NMR (DMSO-d6): δ = 6.62 (2H, br.s, NH2), 7.31 (2H, d, JHH = 8.7 Hz, 2CHortho of Ph–
3
N C), 7.37–7.47 (6H, m, 2Ph), 7.52 (2H, d, JHH = 7.2 Hz, 2CHortho of Ph-CO). 13C NMR
=
=
(DMSO-d6): δ = 103.68 ( C–COPh), 127.83, 128.59, 128.66, 129.00, 129.32, 131.26 (1°C,

14 H. Kabirifard et al.
=
=
=
2Ph), 133.72 (Cipso of Ph-CO), 134.33 (Cipso of Ph-N C), 160.41 ( C–NH), 168.56 (C N),
·+
=
=
175.65 (C O, thioester), 197.98 (C O, ketone) ppm. EI–MS: m/z (%) = 310 (M 2, 6), 308
+
(M·+, 58), 281 (8), 253 (18), 221 (24), 208 (36), 105 (100), 91 (52), 77 (73), 65 (28), 51 (34).
Anal. Calcd for C17H12N2O2S (308.35): C, 66.22%; H, 3.92%; N, 9.08%; found: C, 66.48%; H,
3.75%; N, 9.31%.
4.5.2.3. 5-(Benzoyl-N-phenylthiocarbamoylmethylene)imidazolidine-2,4-dione (8). Pale yel-
low powder; yield: 0.08 g (23%); m.p.: 248–250°C. IR (KBr): v¯ = 3435, 3239 (NH), 3061
=
=
=
(CH, aromatic), 1751, 1704 (2C O, amide), 1625 (C O, ketone), 1592 (C C), 1577 (NH),
1
1539, 1374, 1133 (C–N, NH, C S, thioamide) cm−1. H NMR (DMSO-d6): δ = 7.28 (2H,
=
3
3
d, JHH = 8.0 Hz, 2CHortho of Ph-NH), 7.38–7.50 (6H, m, 2Ph), 7.74 (2H, d, JHH = 7.5 Hz,
2CHortho of Ph-CO), 8.69, 10.13, 11.04 (3H, 3br.s, 3NH). 13C NMR (DMSO-d6): δ = 113.57
=
( C–COPh), 128.03, 128.38, 128.83, 129.18, 129.72, 131.70 (1°C, 2Ph), 133.16 (Cipso of Ph-
=
=
=
CO), 139.86 (Cipso of Ph-NH), 158.86 ( C–NH), 163.76, 167.41 (2C O, amide), 188.67 (C S),
·+
=
197.67 (C O, ketone) ppm. EI–MS: m/z (%) = 351 (M , 4), 318 (11), 309 (57), 280 (19), 252
(7), 221 (27), 105 (100), 77 (64), 58 (84). Anal. Calcd for C18H13N3O3S (351.38): C, 61.53%;
H, 3.73%; N, 11.96%; found: C, 61.74%; H, 3.49%; N, 11.81%.
4.5.2.4. 3-(Benzoyl-N-phenylthiocarbamoylmethylene)-1,2,3,4-tetrahydroquinoxalin-2-one (9).
Orange powder; yield: 0.31 g (79%); m.p.: 320–322°C. IR (KBr): v¯ = 3450, 3152 (NH), 3049
=
=
=
(CH, aromatic), 1748 (C O, amide), 1636 (C O, ketone), 1586 (C C), 1573 (NH), 1536, 1393,
1133 (C–N, NH, C S, thioamide) cm−1. 1H NMR (DMSO-d6): δ = 7.09–8.17 (14H, m, 3Ph),
=
13
=
8.54, 11.90, 13.88 (3H, 3br.s, 3NH). C NMR (DMSO-d6): δ = 111.83 ( C–COPh), 114.91,
115.56, 123.45, 127.78, 128.14, 128.54, 129.22, 129.64, 130.20, 133.47, (14C, 3Ph), 136.53
(Cipso of Ph-CO), 139.26 (Cipso of Ph-NH), 149.38 (C8a), 155.71 (C4a), 163.37 (C3), 170.19
·+
=
=
=
(C O, amide), 188.25 (C S), 195.67 (C O, ketone) ppm. EI–MS: m/z (%) = 399 (M , 3),
380 (40), 369 (26), 323 (10), 308 (31), 278 (19), 251 (6), 220 (5), 134 (33), 105 (30), 77 (100),
67 (46), 57 (92). Anal. Calcd for C23H17N3O2S (399.46): C, 69.15%; H, 4.29%; N, 10.52%;
found: C, 69.46%; H, 4.08%; N, 10.75%.
4.5.2.5. 4-Benzoyl-3-(2-hydroxy-5-methylphenylamino)-5-phenylimino-2,5-dihydrothiophene-
2-one (10). Orange crystal; yield: 0.33 g (79%); m.p.: 248–250°C. IR (KBr): v¯ = 3655 (OH,
=
Free) 3442 (NH), 3255 (OH), 3062 (CH, aromatic), 2917 (CH, aliphatic), 1756 (C O, thioester),
1
1680 (C O, ketone), 1620 (C N), 1583 (C C), 1510 (NH) cm−1. H NMR (DMSO-d6):
=
=
=
δ = 6.27 (1H, s, CHortho of Ph-NH), 6.73 (1H, d, 3JHH = 8.4 Hz, CHpara of Ph-NH), 6.80 (1H, d,
3JHH = 8.4 Hz, CHmeta of Ph-NH), 7.34–7.55 (10H, m, 2Ph), 10.17, 13.29 (2H, 2br.s, OH, NH).
13
=
C NMR (DMSO-d6): δ = 19.94 (CH3), 105.15 ( C–COPh), 115.75, 123.27, 125.19, 126.03,
127.51, 128.14, 128.43, 128.83, 128.94, 130.34, 130.72, 133.60, 136.27, 148.79 (18C, 3Ph),
=
=
=
=
160.05 ( C–NHAr), 164.81 (C N), 175.78 (C O, thioester), 197.56 (C O, ketone) ppm. EI–
MS: m/z (%) = 416 (M·+ 2, 4), 414 (M·+, 40), 385 (6), 325 (24), 309 (7), 210 (85), 104 (26), 91
+
(17), 77 (100), 65 (17), 51 (38). Anal. Calcd for C24H18N2O3S (414.48): C, 69.55%; H, 4.38%;
N, 6.76%; found: C, 69.89%; H, 4.49%; N, 6.54%.
Disclosure statement
No potential conflict of interest was reported by the authors.
Supplemental data
Supplemental data for this article can be accessed at http://dx.doi.org/10.1080/17415993.2015.1074687.

Journal of Sulfur Chemistry 15
ORCID
Hassan Kabirifard
http://orcid.org/0000-0003-2680-8051
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