Organocatalyzed and mechanochemical solvent-free synthesis of novel and functionalized bis-biphenyl substituted thiazolidinones as potent tyrosinase inhibitors: SAR and molecular modeling studies

Article abstract of DOI:10.1016/j.ejmech.2017.04.021

Eluding the involvement of solvents in organic synthesis and introducing environment friendly procedures can control environmental problems. A facile and an efficient solvent free mechanochemical method (grinding) is achieved to synthesize novel bis-biphe

Full text of DOI:10.1016/j.ejmech.2017.04.021

Accepted Manuscript
Organocatalyzed and mechanochemical solvent-free synthesis of novel and
functionalized bis-biphenyl substituted thiazolidinones as potent tyrosinase inhibitors:
SAR and molecular modeling studies
Sadaf Mutahir, Muhammad Asim Khan, Islam Ullah Khan, Muhammad Yar,
Muhammad Ashraf, Sidra Tariq, Ren-long Ye, Bao-jing Zhou
PII:
S0223-5234(17)30275-1
10.1016/j.ejmech.2017.04.021
EJMECH 9368
DOI:
Reference:
To appear in: European Journal of Medicinal Chemistry
Received Date: 29 January 2017
Revised Date: 18 March 2017
Accepted Date: 11 April 2017
Please cite this article as: S. Mutahir, M.A. Khan, I.U. Khan, M. Yar, M. Ashraf, S. Tariq, R.-l. Ye, B.-
j. Zhou, Organocatalyzed and mechanochemical solvent-free synthesis of novel and functionalized
bis-biphenyl substituted thiazolidinones as potent tyrosinase inhibitors: SAR and molecular modeling
studies, European Journal of Medicinal Chemistry (2017), doi: 10.1016/j.ejmech.2017.04.021.
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

ACCEPTED MANUSCRIPT
1
2
3
Organocatalyzed and Mechanochemical Solvent-free Synthesis of Novel and
Functionalized bis-Biphenyl Substituted Thiazolidinones as Potent Tyrosinase
Inhibitors: SAR and Molecular Modeling Studies
a*
4
5
Sadaf Mutahir,a Muhammad Asim Khan,b Islam Ullah Khan, Muhammad Yar,c Muhammad
Ashraf,d Sidra Tariq,a Ren-long Ye b and Bao-jing Zhou b*
6
7
aDepartment of Chemistry, Government College University, Lahore, 54000, Pakistan. E-Mail:
iuklodhi@yahoo.com (I. U. Khan)
8
bSchool of Chemical Engineering, Nanjing University of Science and Technology, Xiaolingwei
200, Nanjing 210094, China. E-Mail: bzhou@mail.njust.edu.cn (B. Zhou)
cInterdisciplinary Research Center in Biomedical Materials, COMSATS Institute of Information
Technology, Lahore, 54000, Pakistan.
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
dDepartment of Chemistry, The Islamia University of Bahawalpur, Bahawalpur-63100, Pakistan.
Abstract
Eluding the involvement of solvents in organic synthesis and introducing environment friendly
procedures can control environmental problems. A facile and an efficient solvent free
mechanochemical method (grinding) is achieved to synthesize novel bis-biphenyl substituted
thiazolidinones using non-toxic and cheap N-acetyl glycine (NAG). Organocatalytic
condensation of a series of Schiff’s bases bearing different substituents with thioglycolic acid
produces a variety of thiazolidinones derivatives in good to excellent yield. In vitro inhibition
studies against mushroom tyrosinase of these thiazolidinone analogues revealed that many of
them possessed good to excellent tyrosinase inhibition at low micro-molar concentrations. In
particular, six compounds exhibited potent inhibitory potential with IC50 values ranging from
0.61±0.31 to 21.61±0.11 µM as compared with that of standard kojic acid (IC50 6.04±0.11 µM).
Further molecular docking studies revealed that the thiazolidinones moiety plays a key role in the
inhibition mechanism by well fitting into the enzyme bounding pocket
Keywords: N-acetyl glycine, Thiazolidinones, Tyrosinase Inhibition
28
1

ACCEPTED MANUSCRIPT
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Introduction
Environmentally benign synthesis of chemicals and pharmaceutical agents remain a challenge
from the very beginning. It has received great attention of scientists and technologists because of
global ecosystem [1-3]. To solve this issue safe solvents, especially water and supercritical CO2
or solvents with minimum vapour pressure (ionic liquids) are usually recommended. It has also
been a good saying that “the best solvent is no solvent” [3]. The harmful effects of chemicals on
the environment can be addressed by omitting solvents from synthetic cycle. Organic synthesis
can be carried out in solvent free conditions [4] for example Mannich reactions [5], Mukaiyama-
Aldol condensation [6], Prins cyclization [7], Suzuki-Miyara coupling reaction [8] and Passerini
reaction [9]. One of the most important approaches for solvent free synthesis is known as
mechanochemistry and its significance has been recognized for long time [10, 11].
Mechanochemical methods have gained interest [12-16] and provide a way to perform reactions
in a neat environment. It follows the twelve rules of green chemistry [17], reduces the E factor
and increases the sustainability of the chemistry [18, 19].
Many reactions have been performed very efficiently and conveniently even with solid reactants
in eco-friendly conditions, which also reduce the cost of solvent. In the present work we
explored the solvent free synthesis of thiazolidinones, an essential pharmacophore by the
constitution. We employed the mechanochemical method by simply using mortar and pestle.
Tyrosinase (EC 1.14.18.1) is a multifunctional, glycosylated, copper-containing enzyme, and it is
found exclusively in melanocytes. Tyrosinase is synthesized by melanosomal ribosomes found
on the rough endoplasmic reticulum and catalyzes two distinct reactions both of which are
essential for biosynthesis of melanin. This process proceeds via conversion of tyrosine to 3,4-
dihydroxy phenylalanine (DOPA), a process termed tyrosinase monophenolase activity. The next
step is the oxidation of DOPA into DOPA quinone, a process called diphenolase activity. The
reactive ortho quinone, DOPA quinone, spontaneously polymerizes to high molecular weight
melanin nonenzymatically [20, 21]. This process is a determinant of mammalian skin color and
is closely related to local hyperpigmentations such as melasma, ephelide and lentigo. Recently, it
has also been suggested that tyrosinase contributes to the neurodegeneration associated with
Parkinson’s disease [22]. Indeed, the unregulated action of tyrosinase can be a factor in a number
of human disease etiologies. Thus, tyrosinase inhibition has been ardently explored as an avenue
for therapies to these diseases. Over the last few decades, a large number of naturally occurring
and synthetic compounds that can act as tyrosinase inhibitors have been reported, but only a few
2

ACCEPTED MANUSCRIPT
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
of them are put into a practical use due to their weak activity or safety concerns. Tyrosinase
inhibitors typically either render the copper within the active site inactive by chelation, obviating
the substrate– enzyme interaction, or they inhibit oxidation via an electrochemical process [23].
We sought to evaluate thiazolidinone skeleton for their tyrosinase inhibition properties and to
elucidate their inhibition mechanisms by molecular docking studies.
Thiazolidinones have been under great intention due to their privileged status in pharmaceutical
sciences. The wonder nucleus gives out different derivatives with all different types of biological
activities [24]. They exhibit a range of pharmacological activities including anti-hyperglycemic
[25], anti-cancer [26], antiarthritic [27, 28], anti-inflammatory [29], anti-microbial [30], anti-
convulsant [31], antidiarrheal [32], antihistaminic [33], anti-diabetic [34], cyclooxygenase
(COX) inhibitory [35], antagonist [36], cardioprotective [37], necrosis factor-α antagonist [38],
antitubercular [39] and as anti-HIV agents [40].
The first ever pharmacological evaluation of thiazolidinone as anti-tuberculosis (TB) agent was
reported by Italian scientist, Vistentini’ in 1954 [41] and then Marshall and Vallance reported the
anti-convulsing activity in the same year [42]. In 1982, Sohda and co-workers evaluated
thiazolidinones in hyperglycemia. Later in 1997, FDA (Food and Drug Administration) approved
“troglitazone” (TZD) in hyperglycemic conditions [43, 44]. Thereafter, in 1999, two more TZD
derivatives, ‘rosiglitazone’ and ‘pioglitazone’ gained FDA (Food and Drug Administration)
approval [45]. Moreover, a vast of studies have been done on the role of thiazolidinones and the
risk of incident congestive heart failure among patients with type-2 diabetes mellitus [46-48]. In
2011, Wei and Wan studied the role of thiazolidinones in bone remodeling [49, 50].
In the recent decades, the synthesis of substituted thiazolidinones and related compounds has
attracted considerable attention because these compounds constitute the structural frameworks of
several naturally occurring alkaloids that show a wide range of pharmaceutical and industrial
importance [51]. Subsequently, there have been uninterrupted curiosities in the improvement of
new synthetic protocols for the construction of the 4-thiazolidinone scaffold [52-62].
Moisture and oxygen free, inexpensive and non-toxic organocatalysts are very effective for
chemical conversions [4]. They are usually preferred over transition metal catalysts in
pharmaceutical synthesis. Our group planned to seek potent and environment friendly
organocatalyst for the synthesis of novel biologically potent pharmacophores [63-66] with better
yield and easy purification workup [67]. Here, we propose a novel synthetic protocol for the
synthesis of new benzidine based thiazolidinone analogues using NAG as an organocatalyst.
3

ACCEPTED MANUSCRIPT
93
94
95
96
97
98
Keeping in view the synthetic chemistry of thiazolidinones in literature, it was thought that a
catalyst is required, which can facilitate the removal of water during the cyclocondensation step
of the synthesis as it seems the most critical step in obtaining the higher yields of 4-
thiazolidinones and it can be enhanced by the use of appropriate catalyst. Therefore, we decided
to explore the catalytic potential of NAG as it activates the removal of water by protonation of in
situ moieties (scheme 2).
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
Results and Discussion
Chemistry
In general, our protocol comprises of synthesis of bis-biphenyl thiazolidinones in two steps.
Firstly the selected diamines, benzidine (1) and o-toluidine (2) were refluxed with different
aromatic aldehydes for 4-5 hrs by using ethyl alcohol as a solvent and glacial acetic (few drops)
acid as a catalyst. Solid which appeared after cooling was filtered, washed with n-hexane and
dried. In the second step the intermediates (1a-1f & 2a-2f) formed in the first step condensed
with thioglycolic acid in different conditions and got 5- membered bis-biphenyl substituted
thiazolidinones (3a-3f & 4a-4f) (scheme 1). We selected the reaction of Schiff base (1e) with
thioglycolic acid to optimize the reaction conditions. We performed the reaction under different
catalysts, solvents, and also optimized the temperature and finally summarized the result (table
1). We started the optimization process in the absence of catalyst and using toluene as solvent
where the product was obtained 52 % after 12 hr of reflux (table 1 entry 1). We further tested
reaction under different conditions (table 1, entry 2-6). The changes in the conditions led to
different yields of the product (3e) ranging from 25 - 94 %. The minimum yield of the product
was observed in the reaction having Et3N as catalyst (table 1, entry 3). The poor performance is
presumably due to Et3N not promoting a clean cyclisation process in the conversion of Schiff
base to thiazolidinone (3e). The yield of the product was improved by performing the reaction in
the presence of NAG as catalyst and toluene as solvent resulting in the production of 88 % of 3e
(table 1, entry 5). The catalytic action of NAG was also observed in the absence of solvent only
providing mechanochemical conditions. After screening all the conditions, it was found that this
mechanical energy has promotion effects on the reaction and this was emerged as the best choice
among all provided conditions which yield the maximum % age (94 %) of the product (table 1,
entry 6).
4

ACCEPTED MANUSCRIPT
123
124
125
126
127
Scheme 1: Synthesis of Schiff bases from 1 & 2 (1a-1f) and (2a-2f). Synthesis of bis-biphenyl
substituted thiazolidinones (3a-3f & 4a-4f) from 1a-1f and 2a-2f.
128
129
130
131
132
133
134
135
136
137
Subsequently, the amount of NAG required for this reaction in solvent-free and
mechanochemical environment was also investigated (table 1, entry 1-4). The maximum amount
of the product was calculated by using 2.0 equivalents of NAG as catalyst (table 1, entry 4) and it
was observed that the amount of NAG is reciprocal to the product yield up to the maximum
concentration of 2 equivalents. Decreasing amount of NAG decreased the amount of product
(table 1, entry1-3) and vice versa. Thus, 2 equivalent of NAG as catalyst in solvent-free
environment is the optimized condition for this reaction (graph 1). With the optimized conditions
in hands, a series of Schiff bases were applied to establish the scope and generality of this
protocol affording the respective thiazolidinone in good to excellent (79-92 %) yields in 5-8 hrs
5

ACCEPTED MANUSCRIPT
1
13
138
139
140
of reflux (figure 1). The final products were identified by FTIR, HNMR, CNMR and CHNS
analysis (see SI).
Table 1: Optimization of conditions for the synthesis of 3e
Temp Time
Entry Catalyst
Solvent
Yield (%)
(0C)
reflux
r.t
(hr)
12
24
11
10
7
1
2
3
4
5
6
7
None
Et3N
Pyridine
toluene
Et3N
toluene
52
25
46
85
88
94
89
reflux
reflux
reflux
80 0C
100 0C
Hunig Base toluene
NAG
NAG
NAG
toluene
None
None
5
7
141
142
143
Scheme 2: Synthetic protocol for model substrate (3e) under different conditions described in table 1.
144
145
Graph 1: Optimization of concentration of NAG in solvent-free environment.
146
6

ACCEPTED MANUSCRIPT
147
148
Scheme 3: Proposed mechanism of thiazolidinone synthesis via NAG.
149
150
151
Figure 1: Structures of bis-biphenyl thiazolidinones (3a-3f & 4a-4f) synthesized via the solvent free
protocol using NAG as the catalyst.
152
153
The plausible catalytic mechanism of our reaction is illustrated in scheme 3. The first step of the
mechanism involves in the protonation of thioglycolic acid from NAG followed by the
154
155
156
157
158
159
nucleophilic attack of lone pairs of –N of Schiff base at the nucleophilic carbon center producing
an intermediate having germinal diol. Geminal diol is an unstable moiety which is readily
converted to ketonic group by removing the water molecule. In the next step, deprotonation of
this intermediate is facilitated by the attack of
followed by the cyclization of the intermediate.
N-acetyl ethanoate on the –H of the thio group
160
Inhibition against tyrosinase
161
162
163
164
165
The six compounds of this novel series of thiazolidinones showed potent inhibitory potentials
against mushroom tyrosinase which is a key enzyme for melanin biosynthesis (both in plants and
animals) [68]. The inhibitory potential depends upon the size, shape and the interactive forces
between the inhibitor and the enzyme. In order to explore the structure activity relationship, the
two parent molecules, benzidine (1) and 3,3’-dimethylbihenyl-4,4’-diamine (2) and twelve
7

ACCEPTED MANUSCRIPT
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
thiazolidinones derivatives (3a-3f & 4a-4f) were subjected to in vitro tyrosinase inhibition assay
using kojic acid (IC50 6.04±0.11 µM) as the standard. Kojic acid is the famous whitening agent
and widely used in cosmetics, but due to its cytotoxicity level, there is a need to search for better
tyrosinase inhibitors with no or less toxic. The parent molecules have shown negligible activity
(only 20-23 % inhibition for both for both 1 and 2). But the bis-biphenyl substituted
thiazolidinones showed significant potential than the parent molecules and even some of them
show inhibition efficiency better than the standard and their lowest IC50 values reaches
0.61±0.31µM. The bis-biphenyl substituted thiazolidinones contain the electron donating groups
such as hydroxyl, methoxy, dimethyl amino and electron withdrawing groups such as phenyl
ring. The inhibition potential against tyrosinase by six best thiazolidinones derivatives
synthesized decreased as: 3c > 3d > 4d > 3e > 4a > 3a. Among them, 3c was the most potent
with an IC50 value of 0.61±0.31µM. The compound 3c possessed the hydroxyl group along with
thiazolidinone group which might be responsible for its inhibitory potential.
Both compounds 3d (IC50 = 2.41±0.32) and 4d (IC50 = 2.81±0.06) also exhibited potent
inhibition than the standard. Methyl substitutions on the biphenyl ring of 4d seem to have a trifle
effect on its inhibition ability towards the tyrosinase. The analogue 3e (IC50 = 4.41±0.10) also
showed the potent inhibition having methoxy group along with thiazolidinone ring. The
compound 4a having IC50 = 7.71±0.21 also showed good inhibition against the enzyme wherein
thiazolidinone ring is effectively taking part in the inhibition of tyrosinase, though hydroxyl and
methoxy groups enhanced their inhibitory potential. 3a also showed inhibitory potential (IC50 =
21.61±0.11) but three-fold less than 4a having the same skeleton instead of methyl groups at
biphenyl ring.
On the other hand, analogues 3b and 4b did not show any remarkable inhibition against
tyrosinase, which might be due to bulky substituents of these analogues. Compounds 3f, 4c and
4f also did not show any notable inhibition either, suggesting that the positions of substituents
are very crucial. Thus, para- hydoxyl substituted analogues were inactive while ortho substituted
showed inhibition potential. However, in the case of 4c, which is a combination of 3c and 4a,
methyl groups at biphenyl ring render it inactive. These comparisons suggest that thiazolidinone
moiety is necessary but not sufficient to achieve higher inhibition potency.
Table 2: In vitro tyrosinase inhibitory activity of compounds (1 & 2) and (3a-3f & 4a-4f)
(inhibition percentage and IC50 values are means given with SEM).
8

ACCEPTED MANUSCRIPT
198
199
Inhibition (%) at 0.5 mM
23.35±0.17
20.25±0.15
94.85±0.18
20.96±0.19
99.08±0.16
96.32±0.48
98.91±0.19
78.03±0.21
99.63±0.16
51.63±0.14
22.79±0.15
98.43±0.12
49.36±0.47
39.41±0.61
93.51±0.91
IC50 µM
Sample Codes
-
1
2
3a
3b
3c
3d
3e
3f
4a
4b
4c
4d
4e
4f
-
21.61±0.11
-
0.61±0.05
2.41±0.32
4.41±0.11
342.52±0.17
7.71±0.12
<500
-
2.81±0.06
-
-
6.04±0.11
Kojic Acid
200
201
202
203
Order of inhibition of Tyrosinase
3c > 3d > 4d > 3e > 4a > 3a > 3f
204
Molecular Docking Studies
205
206
207
208
209
210
211
212
213
214
215
216
217
218
Molecular dockings were carried out for the inhibitors 3a, 3c, 4a and 4d in order to further
investigate the binding mechanism. Apparently, their large sizes prevent them from entering the
narrow binuclear copper-binding site, however, they are well accommodated and bound at the
surface of the enzyme binding pocket. Thus, the binuclear copper-binding site at the bottom of
the enzyme binding pocket is efficiently blocked so that small ligand such as tropolone is
competitively excluded (see Sec. 3 of the Supporting Information). In general, the two central
benzene rings of the inhibitors are in parallel with the enzyme surface, while one of the two end
benzene substituted TZD moieties fits into the residue pocket formed by Asn81, Cys83, His85,
Glu322, and Thr324. As shown in Fig. 2 (a), both hydroxyl groups at the ortho-position of 3c
form H bonds with the oxygen atoms of two residues, i.e., Gly281 and Glu322, with bond
lengths of 1.77 Å and 2.05 Å respectively. However, no H bond is observed between 4d, whose
hydroxyl groups are at the para- positions, and enzyme. Thus, the interaction between the
inhibitor 3c and enzyme is enhanced by the H bonding interactions, which can lead to high
binding affinity. The similar binding poses of 3c and 4d are compared in fig. 2 (e). For 3a and
9

ACCEPTED MANUSCRIPT
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
4a, their end benzene rings contain no substitutions. We expect their binding by the enzyme less
strong, but more flexible. The methyl groups in the biphenyl ring alter the orientation of the end
benzene groups, which leads to more favorable interactions between the inhibitor and the
enzyme. As compared in fig. 2 (f), the end moieties of 4a orient toward the enzyme binding
pockets better than that of 3a despite the high resemblance of their binding poses. This results in
better shape fitness of the former with the host and thus its higher activity toward the tyrosinase.
The structure of agaricus bisporus mushroom tyrosinase was obtained from the protein data
bank (PDB code: 2Y9X) [69]. The structures of inhibitors were optimized at B3LYP/6-31G (d)
level using Gaussian03 [70]. Docking studies were performed for four inhibitors using Autodock
package [71]. Residues within 5 Å of the inhibitors were identified using VMD program [72].
The distance cut off and angle threshold were set to 3 Å and 150 Å, respectively, in order to
identify the H bonds between the inhibitor and the enzyme.
245
246
247
248
249
250
Figure 2: Illustrations of close contacts between the residues and inhibitors: (a) 3c, (b) 4d, (c) 4a, (d) 3a.
Cu2+ ions are displayed in green spheres. Two H bonds are represented with black dash lines in (a).
Binding modes of 3c (red sticks)and 4d (blue sticks) are compared in (e) and those of 4a (grey stick) and
3a (pink stick) are compared in (f). Surface representations are employed for the enzyme.
10

ACCEPTED MANUSCRIPT
251
252
Conclusions
253
254
255
256
257
258
259
260
261
In summary, we have developed an efficient process for the synthesis of thiazolidinones, in
which the use of NAG as a catalyst along with mechanical energy leads to better yields than
other solvents and catalysts. A mechanistic insight reveals that the catalytic protonation and
subsequent removal of water molecule during the cyclo-condensation of thiazolidinone is the key
step of the reaction. This new catalytic method provides distinct advantages, including: (i) mild
conditions, (ii) high yields, (iii) free of organic solvents with economic and environmental-
friendly perspective (iv), easy to prepare the catalyst and (v) simple work-up procedures, making
it more environmentally friendly and suitable for large scale operations. The new bioactive
compounds were also shown good to excellent inhibition against tyrosinase.
262
263
Experimental Section
264
265
266
267
268
269
General Method
Reagents were purchased from common commercial suppliers and were used without further
purification. Solvents were purified and dried by standard procedures, when necessary. TLC was
1
13
performed on silica coated aluminum plates (6F254, 0.2 mm). H and CNMR were recorded at
400 and 175 MHz, respectively, and DMSO was used as internal standard. IR spectra were
recorded on a Jasco A-302 IR spectrophotometer.
270
271
272
273
274
275
276
277
General procedure for the synthesis of Schiff bases (Intermediate)
Schiff bases of selected diamines were synthesized by reported method with slight modification
[73].To a solution of benzidine (1) or 3, 3’-dimethylbiphenyl-4,4’-diamine (2) (0.01 mol or 1 eq)
in absolute ethanol (8-10 ml) added few drops of acetic acid . Then respective aldehyde (0.022
0
mol or 2 eq) was added into the solution and mixture was refluxed at 80 C for 5-8 hrs. The
reaction was monitored by TLC. After the completion of reaction, kept the reaction mixture in
refrigerator for overnight. The solid was obtained, filtered and washed with water followed by
hexane and recrystallized with suitable solvent.
n-
11

ACCEPTED MANUSCRIPT
278
279
280
281
282
283
284
285
General procedure for the synthesis of thiazolidinones derivatives (3a-3f & 4a-4f) without
any catalyst or reagent
In the reaction flask (50ml) added Schiff base (1 mmol) and marcaptoacetic acid (2.05 mmol) in
0
the presence of toluene (10 ml) and refluxed for 8-12 hours at 80 C. After completion of the
reaction, as confirmed by TLC the reaction mixture was cooled to RT. The solvent was
evaporated under reduced pressure and solid product was washed with aqueous NaHCO3
solution to remove excess of marcaptoacetic acid. The solid product was then dried and
percentage yield was calculated.
286
287
288
289
290
291
292
293
General procedure for the synthesis of thiazolidinones in different solvents by using
catalyst
Schiff base 3e (1 mmol) and thioglycolic acid (2.05 mmol) were refluxed together in a round
bottom flask (50ml) in the presence of 10 ml of selected solvents and appropriate catalyst and
refluxed for 8-12 hours at 80 0C. At the end of the reaction, after confirmation through TLC, the
solvent was evaporated and solid product was washed with aq. NaHCO3 solution to remove
excess of thioglycolic acid. The solid product was then dried and percentage yield was
calculated.
294
295
296
297
298
299
300
301
General procedure for the synthesis of thiazolidinones in the absence of solvent by using
NAG as catalyst
A mixture of Schiff base (1 mmol), thioglycolic acid (2.05 mmol) and NAG (2.0 mmol) were
finely ground in a mortar and pestle. Then finely grounded mixture was transferred to the Pyrex
0
glass round bottom flask which was stirred for 3-5 hours at 100 C. After the completion of
reaction (TLC analysis), the solid was washed with 5 % solution of NaHCO3 to remove excess of
thioglycolic acid. Product was isolated with solvent extraction in ethyl acetate, crystallized, dried
and % age yield was also calculated.
302
303
304
Spectral Data
3,3'-(biphenyl-4,4'-diyl)bis(2-phenylthiazolidin-4-one) (3a)
305
Brown solid; mp = 235-237 °C; IR (KBr)
ν
: 1340 (C-N), 1712 (C=O), 3014 (Ar-C); 1H-NMR:
max
306
307
308
(500 MHz, DMSO): 7.63-7.58 (4H, m, ArH), 7.42 (4H, d, J = 7.05 Hz, ArH), 7.36-7.29 (10H, m,
ArH), 5.37 (2H, s, CH), 3.52 (2H, d, CH2), 3.43 (2H, d, CH2); 13C-NMR: (175 MHz, DMSO);
170.8 (C=O, 2C), 139.7 (2C), 139.1 (2C), 128.7 (2C), 128.2 (2C), 127.5 (2C), 127.5 (2C). 126.9
12

ACCEPTED MANUSCRIPT
309
310
311
312
313
(2C), 126.6 (2C), 125.7 (4C), 119.9 (2C), 119.5 (2C), 52.9, 52.7, 34.2, 34.3; CHNS; Calculated:
C, 70.84; H, 4.76; N, 5.51; O, 6.29; S, 12.61. Found: C, 70.75; H, 4.66; N, 5.56; S, 12.62.
3,3'-(biphenyl-4,4'-diyl)bis(2-(4-(dimethylamino)phenyl)thiazolidin-4-one) (3b)
°
Light Brown solid; mp = 238-240 C; IR (KBr)
ν
: 1348(C-N). 1693 (C=O), 3310 (Ar-C); 1H-
max
314
315
316
317
318
319
320
321
322
323
NMR: (500 MHz, DMSO): 7.64-7.59 (4H, m, ArH), 7.19 (4H, d,
J = 8.8 Hz, ArH), 7.11 (4H, d,
J
= 8.4 Hz, ArH), 6.68-6.61 (4H, m, ArH), 5.16 (2H, s, CH), 3.92 (2H, d, CH2), 3.75 (2H, d,
CH2), 3.06 (12H, s, N-CH3); 13C-NMR: (150 MHz, DMSO): 170.3 (C=O, 2C), 150.0 (2C), 137.9
(2C), 134.7 (2C), 129.6 (2C), 128.3 (2C), 126.5 (2C), 122.6 (4C), 119.6 (4C), 112.7 (2C), 111.9
(2C), 52.5 (2C), 42.9 (4C, CH3), 33.9 (2C); CHNS: Calculated: C, 68.66; H, 5.76; N, 9.42; O,
5.38; S, 10.78. Found: C, 68.61; H, 5.75; N, 9.47; S, 68.60.
3,3'-(biphenyl-4,4'-diyl)bis(2-(2-hydroxyphenyl)thiazolidin-4-one): (3c)
°
1
Yellow solid; m.p.: 232-234 C; IR (KBr)
ν
: 1330(C-N), 1713 (C=O), 3340 (Ar-OH); H-
max
324
325
326
327
328
329
330
331
332
333
NMR: (500 MHz, DMSO): 7.58 (4H, d, = 9.5 Hz, ArH), 7.35 (4H, d, J = 7.06 Hz, ArH), 7.09-
J
7.06 (4H, m, ArH), 6.81-6.72 (4H, m, ArH), 5.56 (2H, s, CH,), 5.02 (2H, s, OH), 3.61 (2H, d,
13
CH2), 3.55 (2H, d, CH2); C-NMR: (175 MHz, DMSO): 167.0 (C=O, 2C), 154.6 (2C), 139.1
(2C), 138.5 (2C), 128.2 (2C), 127.5 (2C), 127.1 (4C), 126.5 (2C), 119.7 (2C), 119.4 (2C), 118.9
(2C), 114.4 (2C), 52.9 (2C), 35.6 (2C); CHNS: Calculated C, 66.65; H, 4.47; N, 5.18; O, 11.84;
S, 11.86. Found: C, 66.60; H, 4.45; N, 5.20; S, 11.85.
3,3'-(biphenyl-4,4'-diyl)bis(2-(4-hydroxy-3-methoxyphenyl)thiazolidin-4-one): (3d)
Yellowish-Brown solid; m.p.: 237-239 °C; IR (KBr)
ν
: 1712 (C=O), 1546 (C=C), 1340 (C-N);
max
334
335
336
337
338
339
340
341
342
343
344
1H-NMR: (500 MHz, DMSO): 7.63 (4H, d,
m, ArH), 6.77 (2H, d, = 9.75 Hz, ArH), 5.57 (2H, s, CH), 5.17 (2H, s, OH-ArH), 3.85 (2H, d,
J = 8.25 Hz, ArH), 7.42 (2H, s, ArH), 7.09-6.91 (6H,
J
CH2), 3.73 (2H, d, CH2), 3.65 (6H, s, OCH3); 13C-NMR: (175 MHz, DMSO): 170.6 (C=O, 2C),
147.5 (2C), 146.5 (2C), 132.8, 132.8, 139.1 (2C), 134.6 (2C), 126.8 (2C), 126.6 (2C), 120.3
(2C), 120.0 (2C), 119.7, 119.5, 115.5, 115.3, 111.5 (2C), 55.7 (2C), 55.6 (2C), 34.2, 34.9;
CHNS: Calculated C, 63.98; H, 4.70; N, 4.66; O, 15.98; S, 10.68. Found: 63.94; H, 4.70; N,
4.68; S, 10.66.
3,3'-(biphenyl-4,4'-diyl)bis(2-(4-methoxyphenyl)thiazolidin-4-one) (3e)
°
1
Dark Brown solid; m.p.: 246-248 C; IR (KBr)
ν
: 1715 (C=O), 1546 (C=C), 1340 (C-N); H-
max
345
346
347
348
NMR: (500 MHz, DMSO): 7.66-7.58 (8H, m, ArH), 7.34 (4H, d, J = 8.5 Hz, ArH), 6.76-6.74
(4H, d,
J = 9.5 Hz, ArH), 5.56 (2H, s, CH), 3.73 (2H, d, CH2), 3.66 (2H, d, CH2), 3.33 (6H, s,
OCH3); 13C-NMR: (175 MHz, DMSO): 170.8 (C=O, 2C), 159.2 (2C), 139.3 (2C), 137.9 (2C),
134.8 (2C), 130.6 (4C), 128.7 (4C), 126.4 (4C), 114.0 (2C), 55.1 (2C), 52.2 (2C), 36.5 (2C);
13

ACCEPTED MANUSCRIPT
349
350
351
352
353
354
CHNS: Calculated C, 67.58; H, 4.96; N, 4.93; O, 11.25; S, 11.28. Found: C, 67.66; H, 4.97; N,
4.89; S, 11.29.
3,3'-(biphenyl-4,4'-diyl)bis(2-(4-hydroxyphenyl)thiazolidin-4-one) (3f)
Yellow Solid; M.P.: 239-241 0C; IR (KBr)
ν
: 1712 (C=O), 1546 (C=C), 3340 (OH); 1H-NMR:
max
355
356
357
358
359
360
361
362
363
364
(500 MHz, DMSO): 7.63-7.59 (8H, m, ArH), 7.42 (2H, d, J =7.6 Hz, ArH), 7.33 (4H, d, J = 9.5
13
Hz, ArH), 5.62 (2H, s, CH), 5.57 (2H, s, OH-ArH), 3.52 (2H, d, CH2), 3.39(2H, d, CH2); C-
NMR: (175 MHz, DMSO): 170.8 (2C), 156.9 (2C), 139.1 (2C), 138.5 (2C), 133.5 (2C), 131.5
(2C), 128.5 (2C), 127.1 (2C), 126.5 (2C), 119.7 (2C), 119.4 (2C), 115.1 (2C), 111.4 (2C), 55.1
(2C), 36.5, 34.0 CHNS: Calculated: C, 66.65; H, 4.47; N, 5.18; O, 11.84; S, 11.86.
Found: C, 66.59; H, 4.57; N, 5.20; S, 11.79.
3,3'-(3,3'-dimethylbiphenyl-4,4'-diyl)bis(2-phenylthiazolidin-4-one) (4a)
0
Coffee-Brown solid; M.P.: 245-247 C; IR (KBr)
ν
: 1735 (C=O), 1546 (C=C), 2340 (C-C);
max
365
366
367
368
369
370
371
372
373
374
375
1H-NMR: (500 MHz, DMSO): 7.52 (2H, s, ArH), 7.46 (2H, d,
J = 8.5 Hz, ArH), 6.88-6.84 (2H,
m, ArH), 6.76-6.74 (2H, m, ArH), 5.62 (2H, s, CH), 3.35 (2H, d, CH2), 3.27 (2H, d, CH2), 2.48
13
(6H, s, CH3); C-NMR: (175 MHz, DMSO): 170.8(2C), 139.3 (2C), 137.9 (2C), 136.4 (2C),
135.6, 135.7, 135.1, 133.6, 131.7, 129.1, 128.6, 128.6, 128.2, 128.1, 127.6, 127.5, 125.0, 124.2,
124.0 (2C), 52.9 (2C), 34.2, 34.0, 18.2, 17.9. CHNS: Calculated: C, 71.61; H, 5.26; N, 5.22; O,
5.96; S, 11.95. Found: C, 71.64; H, 5.36; N, 5.28; S, 11.97.
3,3'-(3,3'-dimethylbiphenyl-4,4'-diyl)bis (2-(4-(dimethylamino) phenyl) thiazolidin-4-one)
(4b)
Dark Brown Solid; M.P.: 250-252 0C; IR (KBr)
ν
: 1732 (C=O), 1546 (C=C), 1340 (C-N); 1H-
max
376
377
378
379
380
381
382
383
384
385
386
NMR (500 MHz, DMSO): 7.50-7.44 (4H, m, ArH), 7.32 (2H, d,
J = 8.05 Hz, ArH), 7.21 (4H, d,
J
= 8.55 Hz, ArH), 6.67-6.63 (4H, m, ArH), 5.50 (2H, s, CH), 3.81 (2H, d, CH2), 3.69 (2H, d,
CH2), 3.06 (12H, s, N-CH3), 2.48 (6H, s, CH3); 13C-NMR (175 MHz, DMSO): 167.0 (2C), 149.5
(2C), 135.27 (2C), 131.64 (2C), 129.86 (2C), 129.66 (2C), 128.89 (2C), 128.29 (2C), 124.79
(2C), 124.0 (4C), 112.7 (2C), 112.3 (2C), 52.7 (2C), 40.1 (2C), 40.0 (2C), 38.9 (2C), 17.9 (2C);
CHNS: Calculated C, 69.42; H, 6.15; N, 9.00; O, 5.14; S, 10.30. Found: C, 69.48; H, 6.17 N,
9.09; S, 10.31.
3,3'-(3,3'-dimethylbiphenyl-4,4'-diyl)bis(2-(2-hydroxyphenyl)thiazolidin-4-one) (4c)
0
Light Brown Solid; M.P.: 247-249 C; IR (KBr)
ν
: 17132 (C=O), 1546 (C=C), 1340 (C-N);
max
387
388
1H-NMR: (500 MHz, DMSO): 7.53 (2H, m, ArH), 7.44 (2H, d,
J = 9.5 Hz, ArH), 7.32 (2H, d, J
= 7.5 Hz, ArH), 6.73 (4H, m, ArH), 6.67-6.61 (4H, m, ArH), 5.56 (2H, s, CH), 5.20 (2H, s, OH-
14

ACCEPTED MANUSCRIPT
13
389
390
391
392
393
394
395
396
397
398
ArH), 4.15 (2H, d ,CH2), 4.00 (2H, d ,CH2), 2.28 (6H, s, CH3); C-NMR: (175 MHz, DMSO):
167.4 (2C), 159.1 (2C), 137.9 (2C), 134.8 (2C), 129.5 (2C), 128.0 (2C), 126.5 (2C), 125.1 (2C),
122.1 (2C), 125.1 (2C), 119.7 (2C), 118.9 (2C), 113.6 (2C), 52.9 (2C), 36.6 (2C), 17.8 (2C);
CHNS: Calculated C, 67.58; H, 4.96; N, 4.93; O, 11.25; S, 11.28. Found: C, 67.58; H, 4.97; N,
4.95; S, 11.31.
3,3'-(3,3'-dimethylbiphenyl-4,4'-diyl)bis(2-(4-hydroxy-3-methoxyphenyl)thiazolidin-4-one)
(4d)
Light Brown Solid; M.P.: 257-259 0C; IR (KBr)
ν
: 1735 (C=O), 1526 (C=C), 3340 (OH); 1H-
max
399
400
401
402
403
404
405
406
407
408
409
NMR: (500 MHz, DMSO); 7.63 (2H, s, ArH), 7.60 (2H, d,
J
= 8.25, ArH), 7.42 (2H, s, ArH),
7.32 (2H, d, = 7.5, ArH), 7.09 (2H, m, ArH), 6.77 (2H, d,
J
J = 9.5, ArH), 5.57 (2H, s, CH), 5.05
(2H, s, OH, ArH), 3.85 (2H, d, CH2), 3.75 (2H, d, CH2), 3.36 (6H, s, OCH3), 2.48 (6H, s, CH3);
13C-NMR: (175 MHz, DMSO); 170.9, 170.6, 147.5 (2C), 146.5 (2C), 137.5 (2C), 137.2 (2C),
134.6 (2C), 130.0 (2C), 126.8 (2C), 126.6 (2C), 120.3 (2C), 119.7 (2C), 119.5 (2C), 115.5,
115.3, 55.7, 55.6, 40.7, 40.1, 34.2, 34.1, 17.9 (2C); CHNS: Calculated C, 64.95; H, 5.13; N,
4.46; O, 15.27; S, 10.20. Found: C, 64.94; 5.12; N, 4.41; S, 10.22.
3,3'-(3,3'-dimethylbiphenyl-4,4'-diyl)bis(2-(4-methoxyphenyl)thiazolidin-4-one) (4e)
Dark Brown Solid; M.P.: 256-258 0C; IR (KBr)
ν
: 1732 (C=O), 1549 (C=C), 1333(C-N); H-
1
max
410
411
412
413
414
415
416
417
418
419
NMR (500 MHz, DMSO): 7.66-7.58 (8H, m, ArH), 6.91 (4H, d, J = 7.0 Hz, ArH), 6.76-6.74
(2H, m, ArH), 5.23 (2H, s, CH), 3.84 (2H, d, CH2), 3.74 (2H, d, CH2), 3.49 (6H,s,OCH3), 3.19
13
(6H, s, CH3); C-NMR (175 MHz, DMSO): 170.8 (2C), 159.1 (2C), 139.3 (2C), 137.9 (2C),
136.4 (2C), 135.6, 135.3, 135.0, 133.6, 131.7, 129.1, 128.7, 128.6, 128.3, 128.1, 127.6, 127.5,
125.0, 124.2, 124.0 (2C), 52.9, 52.7, 34.2, 34.0, 18.2, 17.9; CHNS: Calculated: C, 71.61; H,
5.26; N, 5.22; O, 5.96; S, 11.95. Found: C, 71.64; H, 5.26; N, 5.21; S, 11.91.
3,3'-(3,3'-dimethylbiphenyl-4,4'-diyl)bis(2-(4-hydroxyphenyl)thiazolidin-4-one): (4f)
Yellow Solid; M.P.: 240-242 0C; IR (KBr)
ν
: 1730 (C=O), 1596 (C=C) ,1342 (C-N); 1H-NMR
max
420
421
422
423
424
425
426
427
(500 MHz, DMSO): 7.82 (4H, d,
J
= 9.5 Hz, ArH), 7.78 (4H, d,
J
= 7.6 Hz, ArH), 7.47 (4H, d,
J
=
= 8.2 Hz, ArH), 7.39 (2H, d, = 9.5 Hz, ArH), 7.35 (2H, d,
J
J
= 7.6 Hz, ArH), 7.12 (4H, d,
J
7.9 Hz, ArH), 5.56 (2H, s, CH), 5.20 (2H, s, OH-ArH), 3.89 (2H, d, CH2), 3.83 (2H, d, CH2),
2.49 (6H, s, CH3); 13C-NMR (175MHz, DMSO): 170.8 (2C), 159.1 (2C), 139.1 (2C), 138.5 (4C),
131.8 (2C), 132.0 (2C), 130.2 (2C), 125.5 (2C), 119.7 (2C), 119.42 (2C), 118.9 (2C), 114.4 (2C),
55.12 (2C), 34.00 (2C);17.91 (2C) CHNS: Calculated: C, 67.58; H, 4.96; N, 4.93; O, 11.25; S,
11.2. Found: C, 67.62; H, 5.06; N, 5.03; S, 11.1.
428
Tyrosinase Inhibition Assay
15

ACCEPTED MANUSCRIPT
429
430
431
432
433
434
435
436
The method of Kim et al was employed for enzyme assay [74]. Total volume of 100
µ
L reaction
L mushroom
L 0.5 mM test
compound mixed in 96-well plate. Pre-incubation of contents was carried out for 5 minute at 37
oC. 20
L of 10 mM L-dopamine was added as a substrate after incubation. Contents were mixed
mixture consisted of 60
µL 100 mM phosphate buffer having pH 6.8, 10 µ
tyrosinase enzyme (5 units, Cat. No. T3824-50KU, Sigma Inc. USA) and 10
µ
µ
well and again incubated for about 30 min. At 490 nm absorbance was taken. All reactions were
carried out thrice to attain accuracy. The positive and negative controls were included in the
assay. The enzyme inhibition (%) was calculated by the formula.
437
438
439
440
Inhibition (%) =
Control – Test × 100
Control
IC50 values (concentration at which there is 50% inhibition in enzyme activity) of active
441
442
compounds were calculated using EZ-Fit Enzyme Kinetics Software (Perrella Scientific Inc.
Amherst, USA) after suitable dilutions of the test compounds.
443
444
Molecular Docking
445
446
447
448
449
450
451
452
453
454
455
Docking studies are performed for the four inhibitors using Autodock package [71]. The
structure of agaricus bisporus mushroom tyrosinase was obtained from the protein data bank
(PDB code: 2Y9X) [69]. Before docking, the structures of the inhibitors were optimized at
B3LYP/6-31G(d) level using Gaussian 09 [75]. The Gasteiger charges were adopted as the
partial charge model. The number of grid points in three dimentions was set to 50 * 50 * 50 so
that the grid box fully covered the potential binding zone of the binuclear copper site. The
Lamarckian Genetic Algorithm was employed in conformation search. After docking
calculations, cluster analysis was perfomed to identify the most stable docking conformation.
The analysis of close contacts and hydrogen bonding between the enzyme and inhibitors was
conducted with UCSF Chimera program [76], which was also employed to render Fig. 2 and Fig.
S1.
456
457
458
459
460
Acknowledgements
We acknowledge Higher Education Commission and Ministry of Science and Technology
Pakistan for financial support and National Natural Science Foundation of China (No: 51242001,
51572127 and 5122351). BZ gratefully acknowledges the financial support from “The
Fundamental Research Funds for the Central Universities”, No. 30915011314.
16

ACCEPTED MANUSCRIPT
461
462
463
464
Supplementary Data
Supplementary data (1HNMR and 13CNMR spectra of all Compounds, comparison of the binding
modes of tropolone and a representative graph of the effect of incubation time on the tyrosinase
enzyme activity) related to this article can be found in supporting file.
465
References:
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
[1] J.O. Metzger, Solvent
37 (1998) 2975-2978.
[2] A.L. Garay, A. Pichon, S.L. James, Solvent-free synthesis of metal complexes, Chemical
Society Reviews, 36 (2007) 846-855.
[3] R.A. Sheldon, Green solvents for sustainable organic synthesis: state of the art, Green
Chemistry, 7 (2005) 267-278.
[4] X. Zhang, Z. Wang, K. Xu, Y. Feng, W. Zhao, X. Xu, Y. Yan, W. Yi, HOTf-catalyzed
sustainable one-pot synthesis of benzene and pyridine derivatives under solvent-free
conditions, Green Chemistry, 18 (2016) 2313-2316.
[5] L. El Kaïm, L. Gautier, L. Grimaud, L. Harwood, V. Michaut, The Mannich reaction of
hydrazones: improved reactivity under solvent-free conditions, Green Chemistry, 5 (2003)
477-479.
[6] T.-P. Loh, J.-M. Huang, S.-H. Goh, J.J. Vittal, Aldol reaction under solvent-free conditions:
highly stereoselective synthesis of 1, 3-amino alcohols, Organic letters, 2 (2000) 1291-1294.
[7] D. Clarisse, B. Pelotier, O. Piva, F. Fache, Green chemistry: solvent-and metal-free Prins
cyclization. Application to sequential reactions, Chemical Communications, 48 (2012) 157-
159.
[8] K. Mandai, T. Korenaga, T. Ema, T. Sakai, M. Furutani, H. Hashimoto, J. Takada, Biogenous
iron oxide-immobilized palladium catalyst for the solvent-free Suzuki–Miyaura coupling
reaction, Tetrahedron Letters, 53 (2012) 329-332.
[9] T. Bousquet, M. Jida, M. Soueidan, R. Deprez-Poulain, F. Agbossou-Niedercorn, L. Pelinski,
Fast and efficient solvent-free Passerini reaction, Tetrahedron Letters, 53 (2012) 306-308.
[10] J.F. Fernández-Bertran, Mechanochemistry: an overview, Pure and applied chemistry, 71
(1999) 581-586.
‐free organic syntheses, Angewandte Chemie International Edition,
[11] A. Khan, J. Hashim, N. Arshad, I. Khan, N. Siddiqui, A. Wadood, M. Ali, F. Arshad, K.M.
Khan, M.I. Choudhary, Dihydropyrimidine based hydrazine dihydrochloride derivatives as
potent urease inhibitors, Bioorganic chemistry, 64 (2016) 85-96.
[12] G. Kaupp, Solid-state molecular syntheses: complete reactions without auxiliaries based on
the new solid-state mechanism, CrystEngComm, 5 (2003) 117-133.
[13] G. Cave, C. Raston, 340 9 Microwaves in Cycloadditions JL Scott, Chem. Commun, (2001)
2159-2169.
[14] Y. Usui, K. Sato, M. Tanaka, Catalytic Dihydroxylation of Olefins with Hydrogen Peroxide:
An Organic‐Solvent‐and Metal‐Free System, Angewandte Chemie International Edition,
42 (2003) 5623-5625.
[15] S. Santra, D. Kopchuk, I. Kovalev, G. Zyryanov, A. Majee, V. Charushin, O. Chupakhin,
Solvent-free synthesis of pillar [6] arenes, Green Chemistry, 18 (2016) 423-426.
17

ACCEPTED MANUSCRIPT
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
[16] Z. Li, Z. Jiang, W. Su, Fast, solvent-free, highly enantioselective three-component coupling
of aldehydes, alkynes, and amines catalysed by the copper (II) pybox complex under high-
vibration ball-milling, Green Chemistry, 17 (2015) 2330-2334.
[17] P.T. Anastas, J.C. Warner, Green chemistry: theory and practice, Oxford university press,
2000.
[18] R.A. Sheldon, Organic synthesis-past, present and future, Chemistry and Industry, (1992)
903-906.
[19] R.A. Sheldon, The E factor: fifteen years on, Green Chemistry, 9 (2007) 1273-1283.
[20] S. Halaouli, M. Asther, J.C. Sigoillot, M. Hamdi, A. Lomascolo, Fungal tyrosinases: new
prospects in molecular characteristics, bioengineering and biotechnological applications,
Journal of applied microbiology, 100 (2006) 219-232.
[21] L. Fenoll, M. Penalver, J. Rodrıguez-López, R. Varón, F. Garcıa-Cánovas, J. Tudela,
Tyrosinase kinetics: discrimination between two models to explain the oxidation mechanism
of monophenol and diphenol substrates, The international journal of biochemistry & cell
biology, 36 (2004) 235-246.
[22] J. Segura‐Aguilar, I. Paris, P. Muñoz, E. Ferrari, L. Zecca, F.A. Zucca, Protective and
toxic roles of dopamine in Parkinson's disease, Journal of neurochemistry, 129 (2014) 898-
915.
[23] T.-S. Chang, An updated review of tyrosinase inhibitors, International journal of molecular
sciences, 10 (2009) 2440-2475.
[24] M. Abhinit, M. Ghodke, N.A. Pratima, Exploring potential of 4-thiazolidinone: a brief
review, Int J Pharm Pharm Sci, 1 (2009) 47-64.
[25] T. Fujita, Y. Sugiyama, S. Taketomi, T. Sohda, Y. Kawamatsu, H. Iwatsuka, Z. Suzuoki,
Reduction of insulin resistance in obese and/or diabetic animals by 5-[4-(1-
methylcyclohexylmethoxy) benzyl]-thiazolidine-2, 4-dione (ADD-3878, U-63,287,
ciglitazone), a new antidiabetic agent, Diabetes, 32 (1983) 804-810.
[26] M.M. Ip, P.W. Sylvester, L. Schenkel, Antitumor efficacy in rats of CGP 19984, a
thiazolidinedione derivative that inhibits luteinizing hormone secretion, Cancer research, 46
(1986) 1735-1740.
[27] L.F. da Rocha Junior, M.J.B. de Melo Rêgo, M.B. Cavalcanti, M.C. Pereira, M.G.d.R. Pitta,
P.S.S. de Oliveira, S.M.C. Gonçalves, A.L.B.P. Duarte, M.d.C.A. de Lima, I.d.R. Pitta,
Synthesis of a novel thiazolidinedione and evaluation of its modulatory effect on IFN-γ, IL-6,
IL-17A, and IL-22 production in PBMCs from rheumatoid arthritis patients, BioMed
research international, 2013 (2013).
[28] D. Kaminskyy, D. Khyluk, O. Vasylenko, L. Zaprutko, R. Lesyk, A facile synthesis and
anticancer activity evaluation of spiro [thiazolidinone-isatin] conjugates, Scientia
pharmaceutica, 79 (2011) 763.
[29] A.M. Youssef, M.S. White, E.B. Villanueva, I.M. El-Ashmawy, A. Klegeris, Synthesis and
biological evaluation of novel pyrazolyl-2, 4-thiazolidinediones as anti-inflammatory and
neuroprotective agents, Bioorganic & medicinal chemistry, 18 (2010) 2019-2028.
[30] U. Albrecht, D. Gördes, E. Schmidt, K. Thurow, M. Lalk, P. Langer, Synthesis and
structure–activity relationships of 2-alkylidenethiazolidine-4, 5-diones as antibiotic agents,
Bioorganic & medicinal chemistry, 13 (2005) 4402-4407.
[31] F. Ragab, N.M. Eid, H. El-Tawab, Synthesis and anticonvulsant activity of new
thiazolidinone and thioxoimidazolidinone derivatives derived from furochromones, Die
Pharmazie, 52 (1997) 926-929.
18

ACCEPTED MANUSCRIPT
548
549
[32] O. Mazzoni, D. Bosco, A. Mazzella, P. Grieco, E. Novellino, A. Bertamino, F. Borrelli, R.
Capasso, M.V. Diurno, Synthesis and Pharmacological Activity of 2
{2 [(4 phenyl cyano) piperidino] ethyl} 1, 3 thiazolidin
biology & drug design, 67 (2006) 432-436.
[33] T. Previtera, M. Basile, M.G. Vigorita, G. Fenech, F. Occhiuto, C. Circosta, R.C. de
Pasquale, 3, 3 -Di [1, 3-thiazolidine-4-one] system. II. Anti-inflammatory and anti-
‐
(substituted)‐3‐
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
‐
‐
‐
4
‐
‐
‐
‐4‐ones, Chemical
′
histaminic properties in new substituted derivatives, European journal of medicinal
chemistry, 22 (1987) 67-74.
[34] V. Prabhakar, K. Vipan, Synthesis and antidiabetic activity of N’-[3-(alkyl/aryl substituted)-
4-oxo-1, 3 thiazolidin-2-yeidene]-2-(pyrazin-2-yloxy) acetohydrazide, Acta Pharmaceutica
Sciencia, 52 (2010) 411-415.
[35] A. Taranalli, A. Bhat, S. Srinivas, E. Saravanan, Antiinflammatory, analgesic and
antipyretic activity of certain thiazolidinones, Indian journal of pharmaceutical sciences, 70
(2008) 159.
[36] S. Rollas, S.G. Küçükgüzel, Biological activities of hydrazone derivatives, Molecules, 12
(2007) 1910-1939.
[37] T. Kato, T. Ozaki, K. Tamura, Y. Suzuki, M. Akima, N. Ohi, Novel calcium antagonists
with both calcium overload inhibition and antioxidant activity. 2. Structure-activity
relationships of thiazolidinone derivatives, Journal of medicinal chemistry, 42 (1999) 3134-
3146.
[38] L. Mosula, B. Zimenkovsky, D. Havrylyuk, A.-V. Missir, I.C. Chirita, R. Lesyk, Synthesis
and antitumor activity of novel 2-thioxo-4-thiazolidinones with benzothiazole moieties,
Farmacia, 57 (2009) 321-330.
[39] K. Babaoglu, M.A. Page, V.C. Jones, M.R. McNeil, C. Dong, J.H. Naismith, R.E. Lee,
Novel inhibitors of an emerging target in Mycobacterium tuberculosis; substituted
thiazolidinones as inhibitors of dTDP-rhamnose synthesis, Bioorganic & medicinal chemistry
letters, 13 (2003) 3227-3230.
[40] J. Balzarini, B. Orzeszko, J.K. Maurin, A. Orzeszko, Synthesis and anti-HIV studies of 2-
adamantyl-substituted thiazolidin-4-ones, European journal of medicinal chemistry, 42
(2007) 993-1003.
[41] P. Visentini, Antituberculosis chemotherapeutic action of derivatives of 2-4-
thiazolidinedione. I. Action in vitro of the 2-phenylhydrazone of 2, 4-thiazolidinedione, Il
Farmaco; edizione scientifica, 9 (1954) 274.
[42] P. Marshall, D. Vallance, Derivatives of Succinimide, Glutarimide, Thiazolidinedione and
Methanol, and some Miscellaneous Compounds, Journal of Pharmacy and Pharmacology, 6
(1954) 740-746.
[43] T. Sohda, K. Mizuno, Y. Momose, H. Ikeda, T. Fujita, K. Meguro, Studies on antidiabetic
agents. 11. Novel thiazolidinedione derivatives as potent hypoglycemic and hypolipidemic
agents, Journal of medicinal chemistry, 35 (1992) 2617-2626.
[44] R. Henry, Effects of troglitazone on insulin sensitivity, Diabetic medicine: a journal of the
British Diabetic Association, 13 (1996) S148-150.
[45] R.M. Hindley, Novel compounds, in, Google Patents, 1991.
[46] K.B. Filion, L. Joseph, J.F. Boivin, S. Suissa, J.M. Brophy, Thiazolidinediones and the risk
of incident congestive heart failure among patients with type 2 diabetes mellitus,
pharmacoepidemiology and drug safety, 20 (2011) 785-796.
19

ACCEPTED MANUSCRIPT
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
[47] K.B. Filion, L. Joseph, J.-F. Boivin, S. Suissa, J.M. Brophy, Thiazolidinediones and the
Risk of Incident Congestive Heart Failure Among Patients With Type 2 Diabetes Mellitus: A
Population-Based Nested Case-Control Study, Circulation, 120 (2009) S504.
[48] S. Pastromas, S. Koulouris, Thiazolidinediones: antidiabetic drugs with cardiovascular
effects, Hellenic J Cardiol, 47 (2006) 352-360.
[49] W. Wei, Y. Wan, Thiazolidinediones on PPAR
research, 2011 (2011).
γ: the roles in bone remodeling, PPAR
[50] K.R. Kim, H.J. Kim, S.K. Lee, G.T. Ma, K.K. Park, W.Y. Chung, 15-deoxy-
∆
12, 14-
prostaglandin J 2 inhibits osteolytic breast cancer bone metastasis and estrogen deficiency-
induced bone loss, PloS one, 10 (2015) e0122764.
[51] M. Yusuf, P. Jain, Synthesis and biological significances of 1, 3, 4-thiadiazolines and
related heterocyclic compounds, Arabian Journal of Chemistry, 7 (2014) 525-552.
[52] J. Meshram, P. Ali, V. Tiwari, Zeolite as an efficient and recyclable activation surface for
the synthesis of bis-thiazolidinones: theoretical screening owing to experimental biology,
Green Chemistry Letters and Reviews, 3 (2010) 195-200.
[53] D. Lingampalle, D. Jawale, R. Waghmare, R. Mane, Ionic liquid–mediated, one-pot
synthesis for 4-thiazolidinones, Synthetic Communications®, 40 (2010) 2397-2401.
[54] X. Zhang, X. Li, D. Li, G. Qu, J. Wang, P.M. Loiseau, X. Fan, Ionic liquid mediated and
promoted eco-friendly preparation of thiazolidinone and pyrimidine nucleoside–
thiazolidinone hybrids and their antiparasitic activities, Bioorganic & medicinal chemistry
letters, 19 (2009) 6280-6283.
[55] V. Kanagarajana, J. Thanusua, M. Gopalakrishnana, Green Chem Lett Rev 2009, 2, 161–
167, CrossRef, CAS, Web of Science® Times Cited, 4.
[56] C. Sadashiva, J.N.S. Chandra, C. Kavitha, A. Thimmegowda, M. Subhash, K.S. Rangappa,
Synthesis and pharmacological evaluation of novel N-alkyl/aryl substituted thiazolidinone
arecoline analogues as muscarinic receptor 1 agonist in Alzheimer's dementia models,
European journal of medicinal chemistry, 44 (2009) 4848-4854.
[57] K.G. Desai, K.R. Desai, A facile microwave enhanced synthesis of sulfur-containing 5-
membered heterocycles derived from 2-mercaptobenzothiazole over ZnCl 2/DMF and
antimicrobial activity evaluation, Journal of Sulfur Chemistry, 27 (2006) 315-328.
[58] V. Gududuru, V. Nguyen, J.T. Dalton, D.D. Miller, Efficient microwave enhanced synthesis
of 4-thiazolidinones, Synlett, (2004) 2357-2358.
[59] J. Fraga-Dubreuil, J.P. Bazureau, Efficient combination of task-specific ionic liquid and
microwave dielectric heating applied to one-pot three component synthesis of a small library
of 4-thiazolidinones, Tetrahedron, 59 (2003) 6121-6130.
[60] C.P. Holmes, J.P. Chinn, G.C. Look, E.M. Gordon, M.A. Gallop, Strategies for
combinatorial organic synthesis: Solution and polymer-supported synthesis of 4-
thiazolidinones and 4-metathiazanones derived from amino acids, The Journal of Organic
Chemistry, 60 (1995) 7328-7333.
[61] J. Tierney, The formation of 2, 3‐disubstituted thiazolidin‐4‐ones from s‐α'‐
aminomercaptoacetic acid derivatives, Journal of heterocyclic chemistry, 26 (1989) 997-
1001.
[62] A.R. Surrey, The preparation of 4-thiazolidones by the reaction of thioglycolic acid with
Schiff bases, Journal of the American Chemical Society, 69 (1947) 2911-2912.
[63] S. Mutahir, M. Yar, M.A. Khan, N. Ullah, S.A. Shahzad, I.U. Khan, R.A. Mehmood, M.
Ashraf, R. Nasar, E. Pontiki, Synthesis, characterization, lipoxygenase inhibitory activity and
20

ACCEPTED MANUSCRIPT
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
in silico molecular docking of biaryl bis (benzenesulfonamide) and indol-3-yl-hydrazide
derivatives, Journal of the Iranian Chemical Society, 12 (2015) 1123-1130.
[64] S.A. Shahzad, M. Yar, M. Bajda, L. Shahzadi, Z.A. Khan, S.A.R. Naqvi, S. Mutahir, N.
Mahmood, K.M. Khan, Synthesis, thymidine phosphorylase inhibition and molecular
modeling studies of 1, 3, 4-oxadiazole-2-thione derivatives, Bioorganic chemistry, 60 (2015)
37-41.
[65] S. Riaz, I.U. Khan, M. Bajda, M. Ashraf, A. Shaukat, T.U. Rehman, S. Mutahir, S. Hussain,
G. Mustafa, M. Yar, Pyridine sulfonamide as a small key organic molecule for the potential
treatment of type-II diabetes mellitus and Alzheimer’s disease: In vitro studies against yeast
α
-glucosidase, acetylcholinesterase and butyrylcholinesterase, Bioorganic chemistry, 63
(2015) 64-71.
[66] S. Mutahir, J. Jończyk, M. Bajda, I.U. Khan, M.A. Khan, N. Ullah, M. Ashraf, S. Riaz, S.
Hussain, M. Yar, Novel biphenyl bis-sulfonamides as acetyl and butyrylcholinesterase
inhibitors: Synthesis, biological evaluation and molecular modeling studies, Bioorganic
chemistry, 64 (2016) 13-20.
[67] M. Yar, M. Bajda, S. Shahzad, N. Ullah, M.A. Gilani, M. Ashraf, A. Rauf, A. Shaukat,
Organocatalyzed solvent free an efficient novel synthesis of 2, 4, 5-trisubstituted imidazoles
for α-glucosidase inhibition to treat diabetes, Bioorganic chemistry, 58 (2015) 65-71.
[68] K.-K. Song, H. Huang, P. Han, C.-L. Zhang, Y. Shi, Q.-X. Chen, Inhibitory effects of cis-
and trans-isomers of 3, 5-dihydroxystilbene on the activity of mushroom tyrosinase,
Biochemical and biophysical research communications, 342 (2006) 1147-1151.
[69] W.T. Ismaya, H.J. Rozeboom, A. Weijn, J.J. Mes, F. Fusetti, H.J. Wichers, B.W. Dijkstra,
Crystal structure of Agaricus bisporus mushroom tyrosinase: Identity of the tetramer subunits
and interaction with tropolone, Biochemistry, 50 (2011) 5477-5486.
[70] M. Frisch, G. Trucks, H. Schlegel, G. Scuseria, M. Robb, J. Cheeseman, J. Montgomery Jr,
T. Vreven, K. Kudin, J. Burant, Gaussian 03, revision B. 05; Gaussian, Inc., Pittsburgh, PA,
(2003) 12478.
[71] G.M. Morris, R. Huey, W. Lindstrom, M.F. Sanner, R.K. Belew, D.S. Goodsell, A.J. Olson,
AutoDock4 and AutoDockTools4: Automated docking with selective receptor flexibility,
Journal of computational chemistry, 30 (2009) 2785-2791.
[72] W. Humphrey, A. Dalke, K. Schulten, VMD: visual molecular dynamics, Journal of
molecular graphics, 14 (1996) 33-38.
[73] S. Radi, S. Tighadouini, O. Feron, O. Riant, Y. N Mabkhot, Synthesis and Evaluation of
Certain Symmetrical Schiff Bases as Inhibitors of MDA-MB-241 Human Breast Cancer Cell
Proliferation, Letters in Drug Design & Discovery, 13 (2016) 205-209.
[74] H. Kim, J. Choi, J.K. Cho, S.Y. Kim, Y.-S. Lee, Solid-phase synthesis of kojic acid-
tripeptides and their tyrosinase inhibitory activity, storage stability, and toxicity, Bioorganic
& medicinal chemistry letters, 14 (2004) 2843-2846.
[75] M. Frisch, G. Trucks, H. Schlegel, G. Scuseria, M. Robb, J. Cheeseman, J. Montgomery Jr,
T. Vreven, K. Kudin, J. Burant, Gaussian 03, revision C. 02; Gaussian, Inc.: Wallingford,
CT, 2004, There is no corresponding record for this reference, (2013).
[76] E.F. Pettersen, T.D. Goddard, C.C. Huang, G.S. Couch, D.M. Greenblatt, E.C. Meng, T.E.
Ferrin, UCSF Chimera—a visualization system for exploratory research and analysis, Journal
of computational chemistry, 25 (2004) 1605-1612.
21

ACCEPTED MANUSCRIPT
Highlights:
•
Using bis-biphenyl as a starting compound, a library of, new 4-thiazolidinone
derivatives were designed and synthesized
•
New green method has been reported for their synthesis by using NAG as
organocatalyst
•
•
All compounds were evaluated for their in vitro tyrosinase inhibitory activity.
Six compounds potently inhibit tyrosinase; IC50 values ranging from 0.61±0.31 to
21.61±0.11 µM
•
•
The most potent compound, 3c, inhibited tyrosinase activity with an IC50 value of
0.61±0.31 µM
SAR is established by molecular modeling studies