Synthesis and dynamic NMR studies of novel hydantoin and thiohydantoin derivatives. Crystal structure of diethyl 2-(4,4-diaryl-2,5-dioxoimidazolidin-1-yl) fumarate and diethyl 2-(4,4-diaryl-2-mercapto-5-oxo-4,5-dihydro-1H-imidazol-1-yl)fumarate

Article abstract of DOI:10.3184/174751917X14932244903881

The reaction of stoichiometric amounts of dialkyl acetylenedicarboxylates with triphenylphosphine in the presence of hydantoins or thiohydantoins afforded stable crystalline phosphorus ylides. These compounds undergo smooth elimination of PPh3 to produce

Full text of DOI:10.3184/174751917X14932244903881

JOURNAL OF CHEMICAL RESEARCH 2017
VOL. 41 MAY, 309–313
RESEARCH PAPER 309
Synthesis and dynamic NMR studies of novel hydantoin and thiohydantoin
derivatives. Crystal structure of diethyl 2-(4,4-diaryl-2,5-dioxoimidazolidin-1-yl)
fumarate and diethyl 2-(4,4-diaryl-2-mercapto-5-oxo-4,5-dihydro-1H-imidazol-
1-yl)fumarate
Mohammad M. Ghanbaria*, Marzieh Jamalia, Gyula Battab and Attila C. Bényeic
aYoung Researchers and Elite Club, Marvdasht Branch, Islamic Azad University, Marvdasht, Iran
bDepartment of Organic Chemistry, University of Debrecen, Hungary
cDepartment of Physical Chemistry, University of Debrecen, Hungary
The reaction of stoichiometric amounts of dialkyl acetylenedicarboxylates with triphenylphosphine in the presence of hydantoins or
thiohydantoins afforded stable crystalline phosphorus ylides. These compounds undergo smooth elimination of PPh3 to produce dialkyl
2-(4,4-diaryl-2,5-dioxoimidazolidin-1-yl)fumarate, 4 or dialkyl 2-(4,4-diaryl-2-mercapto-5-oxo-4,5-dihydro-1H-imidazol-1-yl)fumarate, 7.
Single crystal X-ray diffraction study on 4b and 7b proved the structures unambiguously with C=O and SH functionality at the 2-position of
the imidazole ring, respectively. Dynamic effects were observed in the NMR spectra of these compounds and were attributed to restricted
rotation around the carbon-nitrogen single bonds. Rotational energy barrier (ΔG#) for their interconversion process of rotational isomers
equals to (53.6 and 17.2) 2 kcal mol–1.
Keywords: dynamic 1H NMR, hydantoin, thiohydantoin, phosphorus ylides, X-ray diffraction
The imidazole nucleus is found in a wide variety of natural
products and also in pharmacologically active compounds
such as antibiotics, antiarthritics, antihypercholesteremics,
sodium channel modulators, glucagon receptors and as
cholesterol acyltransferase and blood platelet aggregation
inhibitors.1–4 Different substituted imidazoles show various
biological activities such as antimicrobial, anti-inflammatory,
antibacterial, anti-allergic activity, inhibitors of p38 MAP
kinase, fungicides, herbicides, plant growth regulators.5–7 More
recently, interest in imidazoles has augmented due to their role
as green solvents by means of ionic liquids and in organometallic
chemistry as N-heterocyclic carbenes. As part of our study on
the heterocyclic and carbocyclic systems,8–10 we report the
synthesis, X-ray structural characterisation, and conformational
behavior of functionalised hydantoins and thiohydantoins in the
present paper. Thus, the reaction of hydantoins and activated
acetylenes in the presence of triphenylphosphine (Ph3P) leads to
phosphoranes 3 and 6,10,11 which undergo elimination reactions
in boiling toluene to produce 4 and 7, respectively, in good
yields. Syntheses of 3 and 6 have been reported previously.
Some of these compounds exhibited dynamic H NMR effect
that affords good information regarding the interchangeable
process of rotational isomers that provide important kinetic
data (Scheme 1).
1
Results and discussion
Synthesis of 3-hyantoin and 3-thiohydantoin fumarates
The reaction of hydantoin 1 or thiohydantoin 5 with diethyl
acetylenedicarboxylate in the presence of triphenylphosphine
proceeded at room temperature in CH2Cl2, and was complete
1
within a few hours. H and 13C NMR spectra of the crude
products clearly indicated the formation of stable phosphorus
ylides 3 and 6.10,11 No other products than 3 or 6 were detected.
These compounds, when under reflux conditions, produce
dialkyl
2-(4,4-diaryl-2,5-dioxoimidazolidin-1-yl)fumarate
4 and dialkyl 2-(2-mercapto-4,4-diaryl-5-oxo-4,5-dihydro-
1H-imidazol-1-yl)fumarate 7 (Table 1). The structures of
H
O
O
N
O
Ar
Ar
H
CO2R
PPh3
N
Ar
Ar
HN
CO2R
N
Ar
NH
N
+
PPh
3
+
CO2R
H
O
Ar
RO2C
O
O
RO2C
CO2R
1
2
3
4
H
S
S
N
SH
Ar
Ar
CO2R
PPh3
N
Ar
Ar
HN
CO2R
N
Ar
NH
N
+
PPh
3
+
CO2R
H
O
Ar
RO2C
O
O
RO2C
CO2R
5
2
6
7
Scheme 1
* Correspondent. E-mail: mail: dzb04982@wit.edu.cn

310 JOURNAL OF CHEMICAL RESEARCH 2017
Table 1 The 3-hyantoin and 3-thiohydantoin fumarates
N–H hydrogen of compound 2, at the vinylphosphonium cation
9 to form the phosphoranes 6. Ylides 6 with a proton shift
and then tautomerisation produce the intermediates 11, which
apparently undergo an elimination reaction to produce the final
products 7 (Scheme 2).
Entry
Ar
R
Products
1
2
3
4
5
6
7
8
9
10
C6H5
C6H5
Me
Et
Me
Et
Me
Et
Me
Et
4a
4b
4c
4d
4e
4f
7a
7b
7c
7d
4-MeC6H4
4-MeC6H4
4-MeOC6H4
4-ClC6H4
C6H5
C6H5
4-MeC6H4
4-MeC6H4
X-ray crystallographic study of 4b
Weakly diffracting single crystals of 4b were grown by
evaporative crystallisation from a mixture of diethyl ether and
acetone solution, however, suitable crystals were not obtained
for 4a, 4c and 4d. The light atom structure and the applied
Mo radiation resulted in low ratio of measured reflections with
high intensities. However, the structure is in agreement with the
expected structure. An ORTEP plot of the crystal structure of
4b is shown in Fig. 1.
Me
Et
compounds 4 and 7 were deduced from their elemental analyses
1
1
1
and H, 13C, H–1H COSY, H–13C HSQC and HMBC spectra.
The structures of compounds 4b and 7b were further verified
by single crystal X-ray diffraction measurement.
The mass spectra of the compounds isolated from the 4b and
7b were determined using electrospray ionisation (ESI) mass
spectrometry. The compound derived from 4b showed molecular
ions at 445.1 ([M + Na]+, 100). Similarly the compound derived
from 7b showed molecular ions at 461.1 ([M + Na]+, 100). The
1H NMR spectrum of 4b displayed two triplets at δ 1.22 and
1.34 corresponding to the two methyls, two quartets at δ 4.20
and 4.38 correspond to the two methylene groups, a singlet peak
at δ 7.17 is assigned to the CH and a singlet at δ 8.16 corresponds
to the NH. In the 1H NMR spectrum of 7b, the two triplets are
at δ 0.99 and 1.19 for the two methyl groups and the methylene
groups are displayed as a multiplet at δ 3.88–4.02 and a quartet
at δ 4.21, a singlet at δ 7.11 corresponds to the CH and a singlet
at δ 10.92 corresponding to the SH. Further evidence of the
structure was obtained from the 13C NMR spectra.
Although we have not yet established experimental proof
for the mechanism of the formation of compounds 6 and 7, a
plausible mechanism was proposed as shown in Scheme 2. It is
reasonable to assume that phosphorus ylide 6 results from the
initial addition of Ph3P to the acetylenic ester and subsequent
protonation of the 1:1 adduct 8, followed by attack of the
anionic nitrogen of 10, formed by deprotonation of the acidic
Fig. 1 ORTEP view of 4b at 50% probability level with partial numbering.
Selected bond lengths (Å) and angles (o): C(5)–O(5) 1.200(5), C(2)–O(2)
1.203(5), N(3)–C(4) 1.447(5), N(1)–C(11) 1.411(5), C(11)–C(12) 1.301(6),
C(12)–C(13) 1.482(7), C(11)–C(21) 1.487(6) ; C(11)–C(12)–C(13) 124.2(3),
C(5)–N(1)–C(11) 122.8(4), N(3)–C(2)–N(1) 105.9(3).
Ar
H
N
S
R
S
CO2
R
CO2
Ar
HN
5
Ar
PPh3
N
PPh3
2
R
CO2
+
N
Ph3P
R
CHCO2
O
Ph3P
Ar
O
RO
2C
R
CO2
8
9
10
6
Ar
O
N
H
S
H
N
S
S
N
Ar
Ar
Ar
Ar
Ar
PPh3
O
PPh3
N
PPh3
H+
N
O
-
PPh3
1.
2.
shift
tautomerisation
N
O
O
7
OR
O
R
CO2
RO
2C
O
OR
OR
OR
6-
(Z)
6-
(E)
11
Scheme 2 Proposed mechanism to produce 7.

JOURNAL OF CHEMICAL RESEARCH 2017 311
X-ray crystallographic study of 7b
Dynamic NMR spectroscopic study
Weakly diffracting single crystals of 7b as DMSO solvate
were grown by evaporative crystallisation from a mixture of
chloroform and dimethylsulfoxide, however, suitable crystals
were not obtained for 7a, 7c and 7d. An ORTEP plot of the
crystal structure of 7b is shown in Fig. 2. The S–H group can
rotate around the C–S bond but as the distance of the sulfur
atom from the nearest oxygen atom is 3.69 Å presence of
intramolecular S–H…O bond can be excluded. (Table 2).
The analysis in relation to the dynamic NMR effect observed
for 4b and 7b in the present work, the variable temperature
spectra are sufficient to calculate the free energy barrier as well
as enthalpy and entropy of activation for the restricted C–N
bond rotation. From the coalescence of the methine protons and
using the expression k = πΔν/1.42, the first-order rate constants
(k) were calculated. Application of the absolute rate theory with
a transmission coefficient of 4b gives a free energy of activation
(ΔG≠) of 53.6 2 kcal mol–1 (Fig. 3). For 7b gives a free energy
of activation (ΔG≠) of 17.2 2 kcal mol–1, where all known
sources of errors are estimated and included (Fig. 4).12
Table 2 The crystallography data for 4b and 7b
Compound
4b
7b
Formula
Formula weight
Crystal system
Space group
a (Å)
b (Å)
c (Å)
C23H22N2O6
422.43
Monoclinic
P21/n
9.37(2)
14.36(4)
15.70(4)
90.00
90.47(9)
90.00
2112(9)
4
C23H22N2O5S·C2 H6OS
516.61
Triclinic
P-1
8.343(1)
10.820(1)
16.090(1)
80.00(1)
75.32(1)
89.58(1)
1382.7(2)
2
Conclusions
In summary, dialkyl 2-(4,4-diaryl-2,5-dioxoimidazolidin-1-
yl)fumarate and dialkyl 2-(4,4-diaryl-2-mercapto-5-oxo-4,5-
dihydro-1H-imidazol-1-yl)fumarate were synthesised via stable
α (˚)
β (˚)
γ (˚)
V (Å3)
Z
Dc (g cm–3)
1.329
888
0.10
1.241
544
0.23
F(000)
ϻ (mm–1)
Reflections collected
Unique reflections with I > 2σ(I)
Parameters refined
GOF on F2
4189
1907
285
1.03
5837
1840
321
0.89
R[F2 > 2σ(F2)]
Rint
0.075
0.047
0.226
0.22, –0.28
0.097
0.070
0.225
0.59, –0.35
wR(F2)
Δρmax, Δρmin (e Å–3)
Fig. 2 ORTEP view of 7b at 40% probability level with partial numbering.
Selected bond lengths (Å) and angles (o): C(4)–O(4) 1.196(6), C(2)–S(1)
1.663(6), N(3)–C(4) 1.397(7), N(3)–C(12) 1.439(7), C(12)–C(13) 1.266(8),
C(12)–C(11) 1.529(5), C(13)–C(14) 1.514(9), C(11)–C(12)–C(13) 119.7(7),
C(5)–N(1)–C(2) 110.9(5), N(1)–C(2)–S(1) 126.3(5).
Fig. 3 The variable temperature 1H NMR spectra of 4b in acetone-d6. (a)
260 K; (b) 265 K; (c) 270 K; (d) 275 K; (e) 280 K; (f) 258 K and (g) 290 K.

312 JOURNAL OF CHEMICAL RESEARCH 2017
using graphite-monochromated Mo–Kα radiation (λ = 0.71073 Å). The
structures were solved by SIR-92 program and refined by full-matrix
least-squares method on F2, with all non-hydrogen atoms refined with
anisotropic thermalparameters using the SHELXL-97 package,14,15
publication material was prepared with the WINGX- suite.16 Hydrogen
atoms were located geometrically and refined in the rigid mode
except N–H or S–H hydrogens which could be found at the difference
electron density map. However in the final stage of refinement these
hydrogen atoms were placed into geometric position, too. The solid
state structure is stabilised by N–H…O hydrogen bond in case of 4b
and also by weak C–H…O hydrogen bonds. Other crystallographic and
experimental details are summarised in Table 2.
Synthesis of phosphorus ylides 3 and 6; general procedure
To a magnetically stirred solution of 0.504 g 1 (2 mmol) and 0.284 g
dimethyl acetylene dicarboxylate (2 mmol) in 5 mL CH2Cl2 was added
dropwise a solution of 0.524 g triphenylphosphine (2 mmol) in 2 mL
CH2Cl2 at 5 °C over 10 min. After 6 h stirring at room temperature, the
product was filtered and washed with cold CH2Cl2.
Synthesis of 4 and 7; general procedure
A mixture of 0.788 g 3a (1.2 mmol) in toluene (30 mL) was refluxed for
48 h. The solvent was removed and the product residue was separated
by silica column chromatography (Merck 230–400 mesh) using
hexane–ethyl acetate as eluent.
Dimethyl 2-(2,5-dioxo-4,4-diphenyl imidazolidin-1-yl)fumarate
(4a): White powder; yield 0.421 g, 89%; m.p. 147–148 °C; IR (νmax
,
cm–1): 3383 (NH), 1724 and 1631 (C=O); 1H NMR (360 MHz, CDCl3)
δ 3.66 (3H, s, MeO), 3.95 (3H, s, MeO), 7.20 (1H, s, CH), 7.32–7.80
(10H, m, CH); 13C NMR (90 MHz, CDCl3) δ 52.9 (MeO), 54.1 (MeO),
71.7 (C), 127.9 (2 × CH), 129.3 (CH), 129.4 (2 × CH), 129.5 (2 × CH),
129.6 (CH), 130.1 (CH), 131.2 (C), 131.5 (CH), 133.0 (CH), 139.3
(2 × C), 154.1 (C=O), 162.6 (OC=O), 163.4 (OC=O), 171.7 (C=O);
Anal. calcd for C21H18N2O6: C, 63.96; H, 4.60; N, 7.10; found: C, 63.90;
H, 4.65; N, 7.14%.
Diethyl 2-(2,5-dioxo-4,4-diphenylimidazolidin-1-yl)fumarate (4b):
Colourless crystals; yield 0.441 g, 87%; m.p. 156–158 °C; IR (νmax, cm–1):
3390 (NH), 1725 and 1630 (C=O); 1H NMR (500 MHz, Acetone-d6) δ 1.21
(3H, t, J = 7.1 Hz, Me), 1.34 (3H, t, J = 7.1 Hz, Me), 4.20 (2H, q, J = 7.1 Hz,
CH2O), 4.38 (2H, q, J = 7.1 Hz, CH2O), 7.17 (1H, s, CH), 7.41–7.57 (10H,
m, CH), 8.16 (1H, s, NH); 13C NMR (125 MHz, Acetone-d6) δ 13.9 (Me),
14.0 (Me), 61.5 (CH2O), 62.8 (CH2O), 70.4 (C), 127.3 (2 × CH), 128.0
(2 × CH), 128.7 (2 × CH), 128.8 (2 × CH), 129.1 (CH), 129.2 (2 × CH),
130.5 (C), 139.5 (2 × C), 152.6 (C=O), 161.8 (OC=O), 162.7 (OC=O),
171.5 (C=O); MS (EI) m/z (%): 422.16 [M]+ (100); Anal. calcd for
C23H22N2O6: C, 65.39; H, 5.25; N, 6.63; found: C, 65.25; H, 5.20; N, 6.62%.
Fig. 4 The variable temperature 1H NMR spectra of 7b in DMSO-d6: (a)
298 K; (b) 300 K; (c) 305 K; (d) 310 K;(e) 315 K; (f) 320 K; (g) 325 K; (h)
330 K; (i) 335 K; (j) 340 K; (k) 345 K and (l) 350 K.
1
phosphorus ylides with good yields and characterised by H,
13C, IR spectroscopy and elemental analysis. Based on acquired
1
dynamic H NMR spectra and X-ray crystallography, we were
able to identify 4b and 7b structures unambiguously. The lack of
H–bonding of SH group in the crystal structure - in contrast to
the solution NMR structure, corroborated with extremely high
12.01 ppm shift - can be explained by the difference between
the crystal and solution structure caused by solvation effects.
Dimethyl
2-(2,5-dioxo-4,4-di-p-tolylimidazolidin-1-yl)fumarate
(4c): White powder; yield 0.400 g, 79%; m.p. 148–149 °C; IR (νmax
,
cm–1): 3406 (NH), 1709 and 1680 (C=O); 1H NMR (360 MHz,
CDCl3:DMSO-d6, 3:1) δ 2.32 (3 H, s, Me), 2.36 (3 H, s, Me), 3.42 (3
H, s, MeO), 3.88 (3 H, s, MeO), 7.16 (1 H, s, CH), 7.24–7.74 (8 H, m,
CH), 9.34 (1 H, s, NH) ppm; 13C NMR (90 MHz, CDCl3) δ 24.0 (Me),
25.3 (Me), 53.5 (MeO), 53.9 (MeO), 72.9 (C), 127.2 (CH), 127.4 (CH),
127.6 (2 × CH), 128.0 (2 × CH), 128.7 (2 × CH), 130.3 (CH), 135.8 (C),
137.1 (C), 137.8 (C), 138.2 (2 × C), 157.4 (C=O), 166.0 (OC=O), 168.5
(OC=O), 177.0 (C=O); Anal. calcd for C23H22N2O6: C, 65.39; H, 5.25;
N, 6.63; found: C, 65.33; H, 5.21; N, 6.65%.
Experimental
Acetylenic esters and triphenylphosphine were obtained from Fluka
and were used without further purification. 5,5-diarylhydantoin and
5,5-diarylthiohydantoin were prepared by known methods.13 Melting
points (uncorrected) were measured on an Electrothermal 9100
apparatus. Elemental analyses for C, H, N and S were performed using
a Heraeus CHN–O-Rapid analyser. The experimental data were in
Diethyl 2-(2,5-dioxo-4,4-di-p-tolylimidazolidin-1-yl)fumarate (4d):
White powder; yield 0.373 g, 69%; m.p. 153–155 °C; IR (νmax, cm–1):
3428 (NH), 1733 and 1653 (C=O); 1H NMR (360 MHz, CDCl3) δ 1.08
(3H , t, J = 6.8 Hz, Me), 1.19 (3H , t, J = 6.84 Hz, Me), 2.33 (3 H, s,
Me), 2.52 (3 H, s, Me), 4.03 (2H, q, J = 6.84 Hz, CH2O), 4.23 (2H, q,
J = 6.8 Hz, CH2O), 7.01 (1H, s, CH), 7.19–7.62 (8H, m, CH), 9.96 (1H,
s, NH); 13C NMR (90 MHz, CDCl3) δ 14.0 (Me), 14.1 (Me), 24.3 (Me),
24.6 (Me), 62.3 (CH2O), 62.5 (CH2O), 70.4 (C), 127.1 (2 × CH), 127.9
(2 × CH), 128.5 (2 × CH), 129.9 (2 × CH), 130.0 (CH), 130.5 (C), 132.0
(2 × C), 134.5 (2 × C), 156.2 (C=O), 161.5 (OC=O), 166.7 (OC=O),
169.5 (C=O); Anal. calcd for C25H26N2O6: C, 66.65; H, 5.82; N, 6.22;
found: C, 66.71; H, 5.89; N, 6.18%.
1
good agreement with the calculated values. H and 13C NMR spectra
(CDCl3) were measured with a Bruker DRX-360 Avance and Avance
II-500 spectrometer. IR spectra were recorded on a Shimadzu IR-460
spectrometer. Mass spectra were determined on a VG Micromass 7035
mass spectrometer at 70 eV with electron impact or on a Finnegan
TSQ mass spectrometer with electrospraying ionisation. Relative
intensities are given in parenthesis. Chromatography columns were
prepared from Aldrich silica gel 70–230 mesh. X-ray quality crystal
of 4b or 7b was mounted on top of a glass capillary using epoxy glue.
Diffraction intensity data collection was carried out at 293(2) K on a
Bruker-Nonius MACH3 diffractometer equipped with a point detector

JOURNAL OF CHEMICAL RESEARCH 2017 313
Dimethyl 2-[4,4-bis(4-methoxyphenyl)-2,5-dioxoimidazolidin-1-yl]
fumarate (4e): White powder; yield 0.480 g, 88%; m.p. 146–147 °C;
IR (νmax, cm–1): 3416 (NH), 1720 and 1672 (C=O); 1H NMR (360 MHz,
CDCl3) δ 3.92 (3H, s, MeO), 4.23 (3H, s, MeO), 4.26 (3H, s, MeO),
4.29 (3H, s, MeO), 6.99 (1H, s, CH), 7.58–7.78 (8H, m, CH), 8.08 (1H,
s, NH); 13C NMR (90 MHz, CDCl3) δ 51.8 (MeO), 52.5 (MeO), 53.8
(MeO), 55.3 (MeO), 74.5 (C), 118.3 (2 × CH), 127.0 (2 × CH), 127.9
(2 × CH), 128.5 (2 × CH), 129.9 (CH), 130.5 (C), 132.0 (2 × C), 150.9
(2 × C), 156.2 (C=O), 161.5 (OC=O), 166.7 (OC=O), 169.5 (C=O);
Anal. calcd for C23H22N2O8: C, 60.79; H, 4.88; N, 6.16; found: C, 60.83;
H, 4.86; N, 6.14%.
9.95 (1H, s, SH); 13C NMR (90 MHz, CDCl3) δ 22.7 (Me), 23.0 (Me),
55.4 (MeO), 55.5 (MeO), 68.2 (C), 128.8 (2 × CH), 129.2 (2 × CH),
130.0 (2 × CH), 130.8 (2 × CH), 131.5 (CH), 132.5 (C), 134.5 (C), 135.2
(C), 135.8 (C), 139.9 (C), 162.3 (OC=O), 162.9 (OC=O), 167.8 (C=O),
171.8 (C=N); Anal. calcd for C23H22N2O5S: C, 63.00; H, 5.06; N, 6.39;
S, 7.31; found: C, 63.06; H, 5.08; N, 6.35; S, 7.28%.
Diethyl 2-(2-mercapto-5-oxo-4,4-di-p-tolyl-4,5-dihydroimidazol-1-
yl)fumarate (7d): White powder; yield 0.397 g, 71%; m.p. 163–165 °C;
IR (νmax, cm–1): 2530 (SH), 1735 (C=O); 1H NMR (500 MHz,
DMSO-d6:CDCl3, 3:1) δ 0.95 (3H, t, J = 7.1 Hz, Me), 1.18 (3H, t,
J = 7.1 Hz, Me), 2.41 (3H, s, Me), 2.50 (3H, s, Me), 3.31–4.02 (2H,
m, ABX3 system, JAX = 7.2, JBX = 7.1, JAB = 10.8 Hz, CH2O), 4.21 (2H,
q, J = 7.0 Hz, CH2O), 7.17 (1H, s, CH), 7.29–7.35 (8H, m, CH), 12.17
(1H, s, SH); 13C NMR (90 MHz, DMSO-d6) δ 14.0 (Me), 14.1 (Me),
29.1 (Me), 29.5 (Me), 61.7 (CH2O), 63.0 (CH2O), 73.4 (C), 127.0 (CH),
127.3 (CH), 127.4 (CH), 127.5 (CH), 128.9 (CH), 129.0 (CH), 129.3
(CH), 130.8 (CH), 131.9 (C), 137.5 (2 × C), 138.8 (C), 138.9 (C), 161.7
(OC=O), 162.6 (OC=O), 172.0 (C=O), 179.3 (C=N). Anal. calcd for
C25H26N2O5S: C, 64.36; H, 5.62; N, 6.00; S, 6.87; found: C, 64.43; H,
5.60; N, 6.01; S, 6.84%.
Diethyl
2-[4,4-bis(4-chlorophenyl)-2,5-dioxoimidazolidin-1-yl]
fumarate (4f): White powder; yield 0.501 g, 85%; m.p. 121–123 °C;
IR (νmax, cm–1): 3384 (NH), 1725 and 1669 (C=O) cm−1; 1H NMR (360
MHz, CDCl3) δ 1.23 (3H, t, J = 7.2 Hz, Me), 1.30 (3H, t, J = 7.2 Hz,
Me), 4.17 (2H, q, J = 7.2 Hz, CH2O), 4.49 (2H, q, J = 7.2 Hz, CH2O),
7.18 (1H, s, CH), 7.32–7.66 (8H, m, CH), 8.69 (1 H, s, NH) ppm;
13C NMR (90 MHz, CDCl3) δ 13.9 (Me), 14.1 (Me), 62.5 (CH2O),
62.7 (CH2O), 70.4 (C), 123.7 (2 × CH), 125.6 (2 × CH), 127.1 (CH),
127.9 (CH), 128.5 (2 × CH), 129.9 (CH), 130.5 (C), 132.0 (C), 134.7
(C), 140.5 (2 × C), 157.8 (C=O), 165.4 (OC=O), 165.8 (OC=O), 171.2
(C=O); Anal. calcd for C23H20Cl2N2O6: C, 56.23; H, 4.10; N, 5.70;
found: C, 56.28; H, 4.06; N, 5.71%.
Received 24 February 2017; accepted 8 April 2017
Paper 1704620
https://doi.org/10.3184/174751917X14932244903881
Published online: 28 April 2017
Dimethyl 2-(2-mercapto-5-oxo-4,4-diphenyl-4,5-dihydroimidazol-
1-yl)fumarate (7a): White powder; yield 0.394 g, 80%; m.p.
1
165–167 °C; IR (νmax, cm–1): 2524 (SH), 1736 (C=O); H NMR (360
MHz, CDCl3) δ 3.77 (3H, s, MeO), 4.07 (3H, s, MeO), 7.40 (1H, s,
CH), 7.59–7.85 (10H, m, CH), 11.80 (1H, s, NH); 13C NMR (90 MHz,
DMSO-d6) δ 53.4 (MeO), 55.0 (MeO), 72.3 (C), 126.0 (2 × CH), 127.1
(2 × CH), 128.5 (2 × CH), 129.5 (2 × CH), 129.9 (2 × CH), 131.5 (CH),
132.0 (C), 136.0 (C), 137.4 (C), 167.0 (OC=O), 168.5 (OC=O), 171.2
(C=O), 185.6 (C=N); Anal. calcd for C21H18N2O5S: C, 61.45; H, 4.42;
N, 6.83; S, 7.81; found: C, 61.50; H, 4.36; N, 6.80; S, 7.85%.
Diethyl 2-(2-mercapto-5-oxo-4,4-diphenyl-4,5-dihydroimidazol-
1-yl)fumarate (7b): Colourless crystals; yield 0.426 g, 81%; m.p.
169–170 °C; IR (νmax, cm–1): 2528 (SH), 1745 (C=O); 1H NMR
(500 MHz, CDCl3) δ 0.99 (3H, t, J = 7.5 Hz, Me), 1.19 (3H, t, J = 7.5
Hz, Me), 3.88–4.02 (2H, m, ABX3 system, JAX = 7.1, JBX = 7.0, JAB
= 10.8 Hz, CH2O), 4.21 (2H, q, J = 7.0 Hz, CH2O), 7.11 (1H, s, CH),
7.29–7.51 (10H, m, CH), 10.92 (1H, s, SH); 13C NMR (125 MHz,
DMSO-d6/CDCl3) δ 13.7 (Me), 13.8 (Me), 61.5 (CH2O), 62.6 (CH2O),
73.7 (C), 126.7 (CH), 126.9 (CH), 127.0 (CH), 127.2 (CH), 127.4 (CH),
127.6 (CH), 128.2 (CH), 128.4 (CH), 128.5 (CH), 128.6 (CH), 130.3
(CH), 132.3 (C), 137.4 (C), 138.7 (C), 139.6 (C), 161.6 (OC=O), 162.3
(OC=O), 172.0 (C=O), 179.7 (C=N); MS (EI) m/z (%): 438.13 [M]+
(100); Anal. calcd for C23H22N2O5S: C, 63.00; H, 5.06; N, 6.39; S, 7.31;
found: C, 63.04; H, 5.09; N, 6.36; S, 7.35%.
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Dimethyl 2-(2-mercapto-5-oxo-4,4-di-p-tolyl-4,5-dihydroimidazol-
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1
160–162 °C; IR (νmax, cm–1): 2532 (SH), 1730, 1694 (C=O); H NMR
(360 MHz, CDCl3) δ 2.31 (3H, s, Me), 2.44 (3H, s, Me), 3.59 (3H, s,
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