Syntheses of new 3-thiazolyl coumarin derivatives, in?vitro α-glucosidase inhibitory activity, and molecular modeling studies

Article abstract of DOI:10.1016/j.ejmech.2016.06.037

3-Thiazolylcoumarin derivatives 1–14 were synthesized via one-pot two step reactions, and screened for in?vitro α-glucosidase inhibitory activity. All compounds showed inhibitory activity in the range of IC₅₀?=?0.12?±?0.01–16.20?±?0.23?μM as co

Full text of DOI:10.1016/j.ejmech.2016.06.037

Accepted Manuscript
Syntheses of new 3-thiazolyl coumarin derivatives, in vitro α-glucosidase inhibitory
activity, and molecular modeling studies
Uzma Salar, Muhammad Taha, Khalid Mohammed Khan, Nor Hadiani Ismail, Syahrul
Imran, Shahnaz Perveen, Sahib Gul, Abdul Wadood
PII:
S0223-5234(16)30527-X
10.1016/j.ejmech.2016.06.037
EJMECH 8698
DOI:
Reference:
To appear in: European Journal of Medicinal Chemistry
Received Date: 25 November 2015
Revised Date: 2 June 2016
Accepted Date: 20 June 2016
Please cite this article as: U. Salar, M. Taha, K.M. Khan, N.H. Ismail, S. Imran, S. Perveen, S. Gul, A.
Wadood, Syntheses of new 3-thiazolyl coumarin derivatives, in vitro α-glucosidase inhibitory activity,
and molecular modeling studies, European Journal of Medicinal Chemistry (2016), doi: 10.1016/
j.ejmech.2016.06.037.
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ACCEPTED MANUSCRIPT
Graphical Abstract
Syntheses of New 3-Thiazolyl Coumarin Derivatives, In Vitro α-Glucosidase Inhibitory
Activity, and Molecular Modeling Studies
Uzma Salar,a Muhammad Taha,*b,c Khalid Mohammed Khan,a Nor Hadiani Ismail,b,c Syahrul Imran,b,c Shahnaz
Perveen,d Muhammad Riaz,e Abdul Wadoode
aH. E. J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi-75270,
Pakistan
bAtta-ur-Rahman Institute for Natural Product Discovery, Universiti Teknologi MARA (UiTM), Puncak Alam Campus, 42300 Bandar Puncak
Alam, Selangor D. E., Malaysia
cFaculty of Applied Science Universiti Teknologi MARA, Shah Alam 40450, Selangor D. E., Malaysia
dPCSIR Laboratories Complex, Karachi, Shahrah-e-Dr. Salimuzzaman Siddiqui, Karachi-75280, Pakistan
eDepartment of Biochemistry, Computational Medicinal Chemistry Laboratory, UCSS, Abdul Wali Khan University, Mardan, Pakistan
O
O
N
O
NH2
O
O
O
O
R1
N
H
H
EtOH, Et3N
EtOH, Et3N
Br
Refux, 3 h
H
N
N
S
+
R1
N
R2
+
Refux, 30 min
H
HN
S
S
N
R2
C
O
N
R1
1-14
R2
Scheme 1: Syntheses of 3-Thiazolylcoumarin Derivatives
O
O
O
O
O
N
S
HN N
Cl
Cl
Cl
OH
Cl
OH
IC50 = 5.31 ± 0.03 µM
Cl
IC50 = 16.54 ± 0.36 µM
O
O
N
S
HN
N
R2
O
R1
Synthetic Derivatives 1-14 (IC50 = 0.12 ± 0.01-16.20 ± 0.23 µM)
Standard Acarbose (IC50 = 38.25 ± 0.12 µM)

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Syntheses of New 3-Thiazolyl Coumarin Derivatives, In Vitro α-Glucosidase
Inhibitory Activity, and Molecular Modeling Studies
a
Uzma Salar,a Muhammad Taha,*b,c Khalid Mohammed Khan, Nor Hadiani Ismail,b,c Syahrul
Imran,b,c Shahnaz Perveen,d Sahib Gul,e Abdul Wadoode
aH. E. J. Research Institute of Chemistry, International Center for Chemical and Biological
Sciences, University of Karachi, Karachi-75270, Pakistan
bAtta-ur-Rahman Institute for Natural Product Discovery, Universiti Teknologi MARA (UiTM),
Puncak Alam Campus, 42300 Bandar Puncak Alam, Selangor D. E., Malaysia
cFaculty of Applied Science Universiti Teknologi MARA, Shah Alam 40450, Selangor D. E.,
Malaysia
dPCSIR Laboratories Complex, Karachi, Shahrah-e-Dr. Salimuzzaman Siddiqui, Karachi-75280,
Pakistan
eDepartment of Biochemistry, Computational Medicinal Chemistry Laboratory, UCSS, Abdul
Wali Khan University, Mardan, Pakistan
Abstract: 3-Thiazolylcoumarin derivatives 1-14 were synthesized via one-pot two step
reactions, and screened for in vitro α-glucosidase inhibitory activity. All compounds showed
inhibitory activity in the range of IC50 = 0.12 ± 0.01-16.20 ± 0.23 ꢀM as compared to standard
acarbose (IC50 = 38.25 ± 0.12 ꢀM), and also found to be nontoxic. Molecular docking study was
carried out in order to establish the structure-activity relationship (SAR) which demonstrated that
electron rich centers at one and electron withdrawing centers at the other end of the molecules
showed strong inhibitory activity. All the synthesized compounds were characterized by
spectroscopic techniques such as EI-MS, HREI-MS, 1H-NMR and 13C-NMR. CHN analysis was
also performed.
Keywords: Synthesis; 3-Thiazolylcoumarin; α-Glucosidase; Structure-activity relationship;
Docking studies, Diabetic complications; Acarbose.
*Corresponding Author: Khalid Mohammed Khan hassaan2@super.net.pk; khalid.khan@iccs.edu; Tel.
00922134824910; Fax. 00922134819018 (KMK); Muhammad taha E-mail: taha_hej@yahoo.com and
muhamm9000@puncakalam.uitm.edu.my, Tel: 0060182901765 (MT)
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Introduction
Being important class of heterocyclic compounds, coumarins have been reported to exhibit wide
spectrum of biological activities, and continuously upraised significant attention of researchers
due to valuable consequences on human health as well as lesser toxicity [1,2]. A wide spectrum
of pharmacological activities was associated with coumarins such as antioxidant [3,4],
antiinflammatory [5], anticoagulant [6], antibacterial [7], cytotoxic effects [8,9], anticancer [10],
antiHIV [11,12] and dyslipidemic activities [13]. Coumarin derivatives also reported as
vasorelaxant [14], free radical scavengers [15], triplet sensitizers [16] and lipid-lowering agents
[17].
Heterocyclic ring thiazole has the privilege to be the core part of medicinally important
compounds [18], due to its noteworthy pharmacological activities including anti-inflammatory
[19], anticonvulsant [20], analgesic [21], pesticidal [22], antiviral [23], antituberculosis [24],
antimicrobial agents, anticancer [25], antitumor [26] and enzyme inhibition activities [27].
Thiazole scaffold has also reported to possess medicinal applications in hypertension [28],
schizophrenia [29], and in the cure of allergies [30].
α-Glucosidase enzyme catalyzes the breakdown of polysaccharides into monosaccharides which
are able to absorb in small intestine and leads to diabetes mellitus. Type ΙΙ diabetes is the most
common type and responsible for nearby 5% death globally [31]. α-Glucosidase enzyme
catalyzes the reaction by hydrolyzing the α-glucosidal bond of isomaltose oligosaccharides
(linear and branched) and releases free α-D-glucose which is mainly responsible to cause
hyperglycemia [32]. Inhibition of enzyme activity is one of the simplest way to treat type ΙΙ
diabetes mellitus by slowing the absorption process of glucose in intestine [33]. Amongst the α-
glucosidase inhibitors, acarbose, miglitol, and voglibose are being clinically used for the cure of
type ΙΙ diabetes mellitus [34-36] and also used as antidiabetic, anticancer and antiHIV agents
[37-39]. Unfortunately, these are 50% less effective than other antidiabetic agents such as
sulfonylurea and metformin. These medications are also associated with some side effects which
include diarrhea, flatulence and abdominal discomfort [40]. So, it is limiting factor to use the
drug alone and often use in combination with other antidiabetic drugs to improve the efficacy.
Our research group has identified a number of heterocyclic compounds for their effectiveness in
medicinal chemistry [41-47] and has already published coumarin and thiazole as potential classes
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of α-glucosidase inhibitors, separately, (Figure-1) [48,49] which prompted us to broaden the
spectrum of our research for further evaluation of these heterocycles in search of potent α-
glucosidase inhibitor. Therefore, we designed a hybrid scaffold by incorporating all
pharmacophores (coumarin, thiazole, hydrazide) in a single molecule to check the α-glucosidase
inhibition. New skeleton of 3-thiazolylcoumarin derivatives 1-14 were synthesized via “one pot”
two step reaction. The reaction is well suited as high atom economic in industrial process due to
bringing out three pharmaceutically active pharmacophores within a single scaffold with lack of
hazardous wastes. To the best of our knowledge, the synthesized compounds are never reported
before chemically and medicinally. Superior activities of compounds 1-14 against α-glucosidase
enzyme in comparison of standard acarbose proved our hypothesis. All compounds found to be
non-cytotoxic.
Figure-1: Rationale of the Current Study
Results and Discussion
Chemistry
3-Thiazolylcoumarin derivatives were synthesized by “one pot” two step reaction. In first step,
different benzohydrazide derivatives were treated with commercially available benzene
isothiocyanates in ethanol (Scheme-1), to afford thiosemicarbazide intermediates within 30
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minutes. In second step, resulted intermediate undergo cyclization reaction when treated with 3-
(bromoacetyl) coumarin in presence of catalytic amount of trimethylamine, to afford 3-
thiazolylcoumarin derivatives. Reaction mixture was refluxed for 3 h to afford the products in
the form of precipitates which were collected via filtration and crystallized from ethyl acetate to
get the pure products in high yields. Synthesized derivatives 1-14 were characterized by different
1
spectroscopic techniques EI-MS, HREI-MS, H-NMR and 13C-NMR. CHN analysis was also
performed.
Scheme 1: Syntheses of 3-Thiazolylcoumarin Derivatives
Stereochemical Assignment of Iminic Double Bond by NOESY
Figure-2: Isomers of Products
Purity of 1H-NMR spectra of all compounds showed the formation of single isomer, either (Z) or
(E) (Figure-2). However, in order to confirm the stereochemistry of iminic double bond, nuclear
overhauser enhance spectroscopy (NOESY) was performed on one of the synthesized
compounds. Spectrum showed many NOESY interactions, some of them confirmed the (Z)
stereochemistry of the compounds. Amidic NH and H-5ʹ of thiazole moiety showed strong
NOESY interaction with H-4 of coumarin ring, as these parts of the molecule are close in space.
The distinctive weak NOESY interaction of H-2ʹʹ, 6ʹʹ and H-3ʹʹ, 5ʹʹ with the H-4 of coumarin as
well as the absence of NOESY interaction with the 2-hydroxy benzamide ring confirmed that the
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ring is close in space with coumarin ring as well as far apart from the benzamide ring. These
observations confirmed the Z stereochemistry of the iminic double bond (Figure-3a).
6
5
7
8
10
H
4
9
H
Weak NOESY Interaction
H
3
5'
1O
2
1'
4'
3'
S
H
O
N
2'
2''
3''
HN
1''
N
4''
OMe
6'''
O
1'''
2'''
6''
5''
5'''
4'''
H
H
OH
3'''
Compound 9
Bold double headed arrow = Strong NOESY interaction
Dashed double headed arrow = Weak NOESY interaction
Figure-3a: NOESY Interactions between Protons of Compound 9
Figure-3b clearly displayed that the formation of Z-isomer is more favorable as compare to E-
isomer. As in case of Z-isomer, rings R1 and R2 are far apart from each other and free from steric
any hindrance, however, R1 and R2 are much closed in E-isomer to create steric hindrance, and
brings out the instability in the molecule.
Figure-3b: Comparison of Stability of E- and Z-Isomer
Table-1: In vitro α-glucosidase inhibitory activity and docking scores of 3-thiazolylcoumarin
derivatives 1-14
Comp. No.
R1
R2
(IC50 ± SEM)a Docking (S) Score
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3.60 ± 0.04
-14.1421
-12.2064
-14.5631
1
2
6.50 ± 0.06
7.40 ± 0.07
3
4
2.90 ± 0.03
8.10 ± 0.07
-14.4937
-12.8795
5
6
16.20 ± 0.23
1.40 ± 0.02
-13.9285
-15.6593
7
8
9.45 ± 0.12
1.10 ± 0.01
-13.7128
-15.8567
9
9.19 ± 0.14
4.06 ± 0.05
2.50 ± 0.03
0.78 ± 0.01
0.12 ± 0.01
-13.9671
-13.3335
-14.5165
-16-1050
-16.5279
10
11
12
13
14
bStandard = Acarbose
38.25 ± 0.12
aIC50 values are expressed as mean ± standard error of mean; bStandard inhibitor for α-glucosidase.
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α-Glucosidase Inhibitory Activities
All the synthetic compounds were screened to check their in vitro α-glucosidase inhibitory
activity. Results showed that all compounds found to have excellent inhibitory activity in the
range of IC50 = 0.12 ± 0.01-16.20 ± 0.23 ꢀM, when compared to the standard acarbose (IC50 =
38.25 ± 0.12 ꢀM) (Table-1). 2H-Chromen-2-one moiety, thiazole as well as arene rings were
collectively played vital role in exhibiting the activity. However, it was observed that compounds
having both electron donating and withdrawing groups displayed strong potential. To verify
these observations molecular docking study was performed. Cytotoxic studies demonstrated that
these compounds are also non-cytotoxic.
Molecular Docking
There was two aims of docking studies: specific structural modeling and accurate prediction of
activity [50]. Molecular docking protocol applied to find out the interactions between inhibitors
and active site of the target protein. To study the interactions of molecular recognition, MOE-
Dock method was utilized [51] which allows the ligands to be flexible during docking so that the
ligands can adjust their different conformations in the binding pocket of the receptor. 3D
structures of the 3-thiazolylcoumarin derivatives were built in builder tool of MOE and 3D
protonation. Energy minimization was carried out for each compound and saved in mdb file for
further assessment in molecular docking. 3D Modeled structure of the α-glucosidase was 3D
protonated and then energy minimization was carried out and allowed the protein to dock to the
fourteen synthetic compounds with most of the default parameters of the MOE. However, for the
best results, we also applied refinement “forcefield” and rescoring function “London dG”
implemented in MOE docking protocol. The binding mode of the ligands in the pocket of the
protein was predicted by using the Pymol software.
Interactions Detail
All the synthetic compounds showed significant in-silico inhibitory activities. The compounds
ranging from 1-9 have same R2 substituent i.e., methoxy benzene but different R1 groups (Table-
1). Among these compounds, the better interaction modes were observed for compounds 4 and 7.
Compound 7 showed the docking score of -15.6593 and its docking analysis revealed that this
compound formed three interactions with the residues Phe157, Tyr313 and Arg312 of the target
7

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protein. Phe300 involved in arene-cation interaction with the benzene ring of the 2H-chromen-2-
one moiety and Arg312 formed another arene-cation interaction with tert-butyl benzene group of
the compound. However, Tyr313 interact with the lone pair of oxygen of methoxy benzene as
given in the Figure-4b. Compound 4 showed the docking score -14.4937 and the 3D interaction
binding mode of the compound was observed having three interactions with the residues His279,
Arg312 and Asn347. Arene-cation interaction was observed between His279 and π electrons of
the dimethyl benzene moiety of the compound. Arg312 displayed arene-cation interaction with
the 2H-chromen-2-one moiety of the same ligand. Asn347 formed polar interaction with the
oxygen of 2H-chromen-2-one group of the inhibitor as shown in the Figure-4a. The increased
activities and good predicted interactions of these compounds might be due to the presence of the
species having electron donating inductive effect (R1) i.e. tert-butyl (compound 7) and dimethyl
(compound 4) as compare to compounds 2, 3, 4, 5, 6 and 8 (Table-1). Comparatively, more
active compound 9 (from 1-9) displayed three polar interactions with the residues Asn241 and
Arg312 with the docking score -15.8567. Asn241 interacted with the lone pair of the keto-
oxygen of 2H-chromen-2-one moiety, whereas Arg312 established two interaction with oxygen
atom of methoxy benzene group of the ligand (Figure-5b). The phenolic group at R1 position is
not directly involved in bonding with the receptors atoms, however, it increased the overall
polarizability of the compound. The good biological activity observed for compound 9 as
compare with compound 4 and 7 might be due to the establishment of three polar interactions
with the active site residues, whereas only single polar contact was observed in case of
compounds 4 and 7 (Figure-4a and 4b). Compound 1 having methoxy group at para position
(R1) showed two interactions with the residues Tyr313 and Phe300 of the receptor protein
(Figure-5a), while compound 6 with methoxy group at ortho position (R1) displayed only one
arene-cation interaction with the residue His279. Similarly, compound 3, having two methoxy
groups (R1) at ortho and para positions, and compound 5, with two methoxy groups at two meta
positions, both displayed two interactions with Phe300, Asn347 and Tyr313, Asn347,
respectively. The positions of the methoxy groups in these two compounds showed negligible
effect in the in-silico study. The docking scores for all compounds are given in Table-1.
Compound 8 with bromo benzene substituent at R1 also showed two interactions. Arg312 formed
arene-cation contact with bromo benzene moiety and His279 established the same contact with
the 2H-chromen-2-one moiety of the compound.
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Figure-4: Docked conformer of the compounds 4 (a), 7 (b) and their interactions with the
residues of the α-glucosidase protein.
Figure-5: Docked conformer of the compound 1(a), 9 (b) and their interactions with the residues
of the α-glucosidase protein.
Among the compounds (10-14), compounds 12, 13 and 14 having similar group (dichloro
benzene) at R2 but different groups at R1 position (Table-1) showed three interactions with the
active site residues. Compound 12 with two methoxy groups at ortho and para positions (R1)
interacted with the residues Phe300, Tyr313 and Asn241. Phe300 formed arene-arene contacts
with the 2H-chromen-2-one moiety and Tyr313 interacted with the oxygen of methoxy group of
the compound. Asn241 bonded to the N atom of amidic moiety as presented in Figure-6a. Due to
the presence of the electron donating groups (OMe) on one side and electron withdrawing groups
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(Cl) on the other side of the compound might be the reason of its polarizability and hence good
activity.
Compound 13 with tert-butyl benzene at R1 also formed three interactions with the active
residues of the target protein as shown in the Figure-6b. Phe157 and Arg439 formed arene-arene
contact with the π electrons of tert-butyl benzene moiety and a polar bond with the oxygen atom
of the 2H-chromen-2-one group of the compound. Tyr313 bonded to the N atom of amidic
moiety. The activity of compound 13 might be driven by the polarizability as in case of
compound 12, due to the presence of electron donating group (tert-butyl) at one end and electron
withdrawing groups (Cl) at another end. Comparing the structures of compounds 13 and 7 which
have about similar structures, the only difference is at R2 position (Table-1). As a result of
structural similarity, both compounds showed interaction with almost similar active site residues
i.e. Phe157 and Tyr313 (Figure-4b and 6b). The minor difference in observed interactions for
compounds 7 and 13 might be due to the difference in geometries of these molecules attributed
by structural difference at R2 position.
Figure-6: Docked conformer of the compound 12 (a), 13 (b) and their interactions with the
residues of the α-glucosidase protein.
The 3D binding mode of compound 14, the most active compound in the series, showed three
interactions with the residues Phe300, Arg312 and Asn241. Arene-arene interaction was
observed between Phe300 and π electrons of the dichloro benzene group of the compound.
Arg312 displayed arene-cation interaction with the phenolic part of the ligand. Asn241 formed
10

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polar interaction with the oxygen of 2H-chromen-2-one group of the inhibitor as shown in the
Figure-7. Unfortunately, we are unable to explain the good activity of compound 14 as compare
to compounds 12 and 13. This might be due to the minor difference in nature of substituents
present at R1 position in these compounds as these groups have about similar electron donating
effect.
In case of compounds 9, 10, 11 and 14, all these compounds have similar R1 group but different
R2 groups (Table-1). On the basis of IC50 value, compound 14 was more active as compare to 9,
10 and 11. The docking results showed that compound 14 interacted with three active site
residues (Asn241, Arg312 and Phe300) as compare to compound 9 which interacted with only
two active site residues (Asn241 and Arg312) (Figure-7 and 5b). The increase biological activity
of compound 14 might be due to the interaction with more active site residues as compare to
compound 9. The difference in the activities and binding modes of these compounds might be
attributed by the different R2 groups present in these compounds.
Figure-7: Docked conformer of the compound 14 and its interactions with the residues of the α-
glucosidase protein.
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From the biological activity and molecular docking studies of these compounds, we have
experienced that compounds having electron rich centers at one end and electron withdrawing or
electronegative centers at the other end were responsible for adequate α-glucosidase inhibitory
activity.
Conclusion
3-Thiazolylcoumarin derivatives 1-14 were found to have superior in vitro α-glucosidase
inhibitory activity in the range of IC50 = 0.12 ± 0.01-16.20 ± 0.23 ꢀM as compared to standard
acarbose (IC50 = 38.25 ± 0.12 ꢀM). Molecular docking study was carried out in order to get
insights about the molecular interaction of compounds with the active site of enzyme. Superior
activity of compounds suggest that these may serve as lead molecules for further research for
getting powerful α-glucosidase inhibitors.
Experimental
Materials and Methods
Analytical grade reagents and solvents were purchased from Sigma-Aldrich and used as
received. Thin layer chromatography was performed on pre-coated silica gel, GF-254. Spots
were visualized under ultraviolet light at 254 and 366 nm. Mass spectra were recorded under
1
electron impact (EI) on MAT 312 and MAT 113D mass spectrometer. The H- and 13C-NMR
were recorded on Bruker AM spectrometer, operating at 300, 400 and 500 MHz instruments. The
chemical shift values are presented in ppm (δ), relative to tetramethylsilane (TMS) as an internal
standard and the coupling constant (J) are in Hz.
In Vitro α-Glucosidase Inhibition Assay
α-Glucosidase inhibitory potential of all synthetic 3-thiazolylcoumarin derivatives were checked
by reported method [52]. Typically, α-glucosidase activity was performed in phosphate buffer 50
mM of pH 6.8 which contains 5% v/v dimethyl sulfoxide. PNP glycoside was used as a
°
substrate. The inhibitors were pre-incubated with enzyme for half an hour at 37 C. Then
substrate was added and the enzymatic reaction was performed for 60 min at 37 °C. Absorbances
were measured by spectrophotometer at 400 nm. The assay was carried in triplicate with five
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different concentrations around the IC50 values that were calculated in the first turn of the
experiments, and the mean values were adopted.
Protein Model Preparation
The sequence of the target protein (α-glucosidase) was retrieved from the uniprot in FASTA
format and protein-blast [53] was carried to get its template in protein databank [54]. The 3D
crystal structures of the template Pdb Id: 3A47 A was retrieved from the protein databank.
Homology Modeling
First the sequence in FASTA format was copied and pasted in the sequence editor of the MOE
(Molecular Operating Environment) software and in MOE window the 3D structure of the
template protein was opened. Chain1 and chain2 showed the target and template protein
sequences, respectively. RMSD value of target-template sequences was calculated prior to
homology modeling. In model refining tool Intermediate was set to Medium, Final model to
Medium, using scoring function Generalized Born/Volume Integral (GB/VI). The Force field
was set to Amber99 with Salvation RField. Total of 30 models were generated, and the final
refine model was loaded to MOE window.
General Experimental Procedure for the Syntheses of 3-Thiazolylcoumarin Derivatives 1-
14
Substituted benzohydrazide derivative (1 mmol), substituted benzene isothiocyanate (1 mmol)
were taken in ethanol (10 mL) into a 100 mL round-bottomed flask were refluxed for half an
hour. Intermediate formation was carefully monitored by thin layer chromatography (TLC).
After the consumption of both starting materials 3-(bromoacetyl) coumarin (1 mmol) and
trimethylamine (1 mmol) were added into above mixture and further refluxed for 3 h. TLC was
taken in order to check the reaction progress. After completion of reaction, reaction mixture was
poured onto about 100 g crushed ice. Precipitates were formed which were filtered to get crude
products which were crystallized from ethyl acetate to afford pure products in high yields.
(Z
)-4-Methoxy-
N-(2-((4-methoxyphenyl)imino)-4-(2-oxo-2H-chromen-3-yl)thiazol-3(2H)-
yl)benzamide (1)
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Dark green solid; Yield: 72%; 1H-NMR (400 MHz, DMSO-d6):
δ
10.33 (s, 1H, NH), 8.76 (s, 1H,
H-4), 7.81 (d, J2
= 8.8 Hz, 2H, H-2ꞌꞌꞌ, 6ꞌꞌꞌ), 7.51 (d, J2
= 8.8 Hz, 3H, H-5, 2ꞌꞌ, 6ꞌꞌ),
ꞌꞌꞌ,3ꞌꞌꞌ/6ꞌꞌꞌ,5ꞌꞌꞌ
ꞌꞌ,3ꞌꞌ/6ꞌꞌ,5ꞌꞌ
7.30 (t, J7,6 = J7,8 = 6.8 Hz, 1H, H-7), 7.12 (d, J3
= 8.8 Hz, 2H, H-3ꞌꞌꞌ, 5ꞌꞌꞌ), 7.03 (d, J8,7 =
ꞌꞌꞌ,2ꞌꞌꞌ/5ꞌꞌꞌ,6ꞌꞌꞌ
9.2 Hz, 1H, H-8), 6.94 (d, J3
ꞌꞌ = 9.2 Hz, 2H, H-3ꞌꞌ, 5ꞌꞌ), 6.90 (t, J6,7 = J6,7 = 8.8 Hz, 1H, H-8),
ꞌꞌ,2ꞌꞌ/5ꞌꞌ,6
4.76 (s, 1H, 5ꞌ δ
), 3.82 (s, 3H, OCH3), 3.72 (s, 3H, OCH3); 13C NMR (75 MHz, DMSO-d6):
164.6, 159.1, 159.0, 158.2, 155.8, 154.1, 153.2, 141.1, 130.4, 128.4, 128.4, 128.1, 127.8, 125.6,
125.2, 124.1, 122.0, 122.0, 118.2, 116.0, 115.2, 115.2, 114.3, 114.3, 100.2, 55.7, 55.5; Anal.
Calcd for C27H21N3O5S, C = 64.92, H = 4.24, N = 8.41; Found C = 64.90, H = 4.26, N = 8.44; EI
MS m/z (% rel. abund.): 499 (M+ , 2), 457 (30), 429 (5), 326 (21), 313 (100), 297 (72); HRMS
(EI) calcd for C27H21N3O5S: m/z = 499.1202, found 499.1182.
(Z
)-N
-(2-((4-Methoxyphenyl)imino)-4-(2-oxo-2
H-chromen-3-yl)thiazol-3(2
H
)-yl)benzamide
(2)
Dark green solid; Yield: 80%; 1H-NMR (400 MHz, DMSO-d6):
δ 10.41 (s, 1H, NH), 8.80 (s, 1H,
H-4), 7.88 (m, 1H, H-5), 7.56 (m, 4H, H-2ꞌꞌꞌ, 3ꞌꞌꞌ, 5ꞌꞌꞌ, 6ꞌꞌꞌ), 7.36 (m, 4H, H-8, 3ꞌꞌ, 5ꞌꞌ), 6.95 (d,
13
J2
= 9.2 Hz, 2H, H-2ꞌꞌ, 6ꞌꞌ), 6.87 (m, 3H, H-6, 7, 4ꞌꞌꞌ), 3.70 (s, 3H, OCH3); C NMR (75
ꞌꞌ,3ꞌꞌ/6ꞌꞌ,5ꞌꞌ
MHz, DMSO-d6):
δ 164.6, 159.3, 159.0, 158.2, 155.7, 153.1, 141.2, 132.0, 132.0, 130.4, 128.7,
128.7, 128.2, 127.8, 127.3, 127.3, 125.6, 125.2, 122.1, 122.1, 118.0, 116.2, 115.1, 115.1, 100.2,
55.7; Anal. Calcd for C26H19N3O4S, C = 66.51, H = 4.08, N = 8.95; Found C = 66.53, H = 4.06,
N = 8.97; EI MS m/z (% rel. abund.): 470 (M+ , 2), 456 (100), 441 (66), 427 (9), 410 (3), 386 (3),
364 (18), 336 (6); HRMS (EI) calcd for C26H19N3O4S: m/z = 469.9096, found 469.9092.
(Z
)-2,4-Dimethoxy-N-(2-((4-methoxyphenyl)imino)-4-(2-oxo-2H-chromen-3-yl)thiazol-
3(2 )-yl)benzamide (3)
H
Dark green solid; Yield: 76%; 1H-NMR (400 MHz, DMSO-d6):
H-4), 7.80 (t, J7,6 = J7,8 = 8.0 Hz, 1H, H-7), 7.65 (d, J5,6 = 8.4 Hz, 1H, H-5), 7.51 (d, J2
δ 10.25 (s, 1H, NH), 8.83 (s, 1H,
=
ꞌꞌ,3ꞌꞌ/6ꞌꞌ,5ꞌꞌ
9.2 Hz, 2H, H-2ꞌꞌ, 6ꞌꞌ), 6.94 (d, J3
= 8.8 Hz, 2H, H-3ꞌꞌ, 5ꞌꞌ), 6.89 (m, 2H, H-6, 8), 6.79 (d,
ꞌꞌ,2ꞌꞌ/5ꞌꞌ,6ꞌꞌ
J6 ꞌꞌꞌ = 8.8 Hz, 1H, H-6ꞌꞌꞌ), 6.73 (bd.s, 1H, H-3ꞌꞌꞌ), 6.69 (d, J5 ꞌꞌꞌ = 8.4 Hz, 1H, H-5ꞌꞌꞌ), 4.89 (s, 1H,
ꞌꞌꞌ,5
ꞌꞌꞌ,6
H-5
ꞌ
), 3.86 (s, 3H, OCH3), 3.83 (s, 3H, OCH3), 3.71 (s, 3H, OCH3); 13C NMR (75 MHz, DMSO-
d6):
δ 164.7, 163.1, 159.3, 159.2, 158.2, 155.7, 153.1, 141.2, 136.3, 130.4, 129.3, 128.4, 127.7,
125.8, 125.3, 122.0, 122.0, 118.2, 116.3, 115.2, 115.2, 110.4, 110.2, 100.0, 98.2, 55.8, 55.8,
14

ACCEPTED MANUSCRIPT
55.6; Anal. Calcd for C28H23N3O6S, C = 63.51, H = 4.38, N = 7.93; Found C = 63.53, H = 4.36,
N = 7.91; EI MS m/z (% rel. abund.): 529 (M+ , 4), 496 (18), 467 (3), 401 (5), 356 (4), 343 (16);
HRMS (EI) calcd for C28H23N3O6S: m/z = 529.1308, found 529.1280.
(
Z N-(2-((4-Methoxyphenyl)imino)-4-(2-oxo-2H-chromen-3-yl)thiazol-3(2H)-yl)-2,4-
)-
dimethylbenzamide (4)
Dark green solid; Yield: 78%; 1H-NMR (400 MHz, DMSO-d6):
H-4), 8.00 (d, J6 ꞌꞌꞌ = 6.0 Hz, 1H, H-6ꞌꞌꞌ), 7.78 (t, J6,5 = J6,7 = 6.0 Hz, 1H, H-6), 7.66 (d, J5,6 = 6.4
δ 10.37 (s, 1H, NH), 8.83 (s, 1H,
ꞌꞌꞌ,5
Hz, 1H, H-5), 7.52 (d, J2
ꞌꞌꞌ = 6.8 Hz, 3H, H-2ꞌꞌ, 6ꞌꞌ, 5ꞌꞌꞌ), 7.49 (s, 1H, H-4), 7.45 (t, J7,6/7,8
ꞌꞌ,3ꞌꞌ/6ꞌꞌ,5ꞌꞌ/5ꞌꞌꞌ,6
= 6.0 Hz, 1H, H-7), 7.22 (s, 1H, 3ꞌꞌꞌ), 7.19 (d, J8,7 = 6.4 Hz, 1H, H-8), 6.94 (d, J3
ꞌꞌ = 6.8 Hz,
ꞌꞌ,2ꞌꞌ/5ꞌꞌ,6
13
2H, H-3ꞌꞌ, 5ꞌꞌ), 4.89 (s, 1H, H-5
ꞌ
), 3.72 (s, 3H, OCH3), 2.56 (s, 3H, CH3), 2.33 (s, 3H, CH3); C
164.7, 159.3, 159.0, 158.4, 155.7, 153.1, 141.2, 138.1, 137.0,
NMR (75 MHz, DMSO-d6):
δ
132.2, 131.2, 130.3, 128.4, 127.8, 127.4, 126.0, 125.6, 125.2, 122.0, 122.0, 118.2, 116.0, 115.1,
115.1, 100.2, 55.6, 21.7, 19.4; Anal. Calcd for C28H23N3O4S, C = 67.59, H = 4.66, N = 8.45;
Found C = 67.57, H = 4.63, N = 8.47; EI MS m/z (% rel. abund.): 497 (M+ , 9), 470 (10), 372
(24), 358 (20), 350 (44); HRMS (EI) calcd for C28H23N3O4S: m/z = 497.1409, found 497.1403.
(Z
)-3,5-Dimethoxy-N-(2-((4-methoxyphenyl)imino)-4-(2-oxo-2H-chromen-3-yl)thiazol-
3(2 )-yl)benzamide (5)
H
Dark green solid; Yield: 74%; 1H-NMR (400 MHz, DMSO-d6):
= 7.6 Hz, 1H, H-5), 7.80 (t, J7,6 = J7,8 = 7.2 Hz, 1H, H-7), 7.51 (d, J8,7 = 8.4 Hz, 1H, H-8), 7.46 (t,
J6,5 = J6,7 = 7.2 Hz, 1H, H-6), 7.34 (d, J2 ꞌꞌ = 8.8 Hz, 1H, H-2ꞌꞌ,6ꞌꞌ), 7.06 (d, J3 ꞌꞌ = 8.8 Hz,
δ 8.76 (s, 1H, H-4), 8.00 (d, J5,6
ꞌꞌ,3ꞌꞌ/6ꞌꞌ,5
ꞌꞌ,2ꞌꞌ/5ꞌꞌ,6
1H, H-3ꞌꞌ,5ꞌꞌ), 6.50 (s, 1H, H-2ꞌꞌꞌ, 4ꞌꞌꞌ, 6ꞌꞌꞌ), 4.79 (s, 1H, H-5
ꞌ), 3.77 (s, 3H, OCH3),3.61 (s, 6H,
2OCH3); 13C NMR (75 MHz, DMSO-d6):
δ
164.8, 161.5, 161.5, 159.3, 159.0, 158.2, 155.8,
153.1, 141.2, 136.1, 130.6, 128.4, 127.8, 125.6, 125.2, 122.2, 122.2, 118.3, 116.0, 115.2, 115.2,
105.3, 105.3, 103.9, 100.0, 55.9, 55.7, 55.7; Anal. Calcd for C28H23N3O6S, C = 63.51, H = 4.38,
N = 7.93; Found C = 63.53, H = 4.40, N = 7.90; EI MS m/z (% rel. abund.): 529 (M+ , 2), 487
(40), 459 (5), 372 (14), 356 (19), 342 (100); HRMS (EI) calcd for C28H23N3O6S: m/z = 529.1308,
found 529.1305.
15

ACCEPTED MANUSCRIPT
(Z
)-2-Methoxy-
N-(2-((4-methoxyphenyl)imino)-4-(2-oxo-2H-chromen-3-yl)thiazol-3(2H)-
yl)benzamide (6)
Dark green solid; Yield: 81%; 1H-NMR (400 MHz, DMSO-d6):
H-4), 7.73 (d, J5,6 = 7.6 Hz, 1H, H-5), 7.53 (m, 4H, H-7, 2ꞌꞌ, 6ꞌꞌ, 4ꞌꞌꞌ), 7.23 (d, J8,7 = J6 ꞌꞌꞌ = 8.0 Hz,
δ 10.33 (s, 1H, NH), 8.75 (s, 1H,
ꞌꞌꞌ,5
2H, H-8, 6ꞌꞌꞌ), 7.11 (t, J7,6 = J7,8 = 7.2 Hz, 1H, H-7), 6.94 (d, J3
= 8.8 Hz, 2H, H-3ꞌꞌ, 5ꞌꞌ),
ꞌꞌ,4ꞌꞌ/5ꞌꞌ,6ꞌꞌ
6.89 (bd.m, 2H, H-3ꞌꞌꞌ, 5ꞌꞌꞌ), 3.87 (s, 3H, OCH3), 3.72 (s, 3H, OCH3); 13C NMR (75 MHz, DMSO-
d6): 164.7, 159.3, 159.0, 158.2, 157.4, 155.7, 153.1, 141.2, 133.2, 131.8, 130.3, 128.2, 127.7,
δ
125.6, 125.2, 122.2, 122.0, 121.0, 118.3, 118.1, 116.2, 115.1, 115.1, 111.3, 100.2, 55.8, 55.6;
Anal. Calcd for C27H21N3O5S, C = 64.92, H = 4.24, N = 8.41; Found C = 64.90, H = 4.26, N =
8.39; EI MS m/z (% rel. abund.): 499 (M+ , 2), 475 (2), 456 (6), 441 (4), 371 (27), 364 (17), 297
(100); HRMS (EI) calcd for C27H21N3O5S: m/z = 499.1202, found 499.1185.
(Z
)-4-(tert-Butyl)-N-(2-((4-methoxyphenyl)imino)-4-(2-oxo-2H-chromen-3-yl)thiazol-3(2H)-
yl)benzamide (7)
Dark green solid; Yield: 72%; 1H-NMR (400 MHz, DMSO-d6):
= 7.2 Hz, 1H, H-5), 7.80 (t, J7,6 = J7,8 = 7.2 Hz, 1H, H-7), 7.51 (d, J8,7 = 8.4 Hz, 1H, H-8), 7.46 (t,
J6,5 = J6,7 = 7.2 Hz, 1H, H-6), 7.37 (m, 6H, H-2ꞌꞌ, 3ꞌꞌ, 5ꞌꞌ, 6ꞌꞌ, 2ꞌꞌꞌ, 6ꞌꞌꞌ), 7.05 (d, J3 ꞌꞌꞌ = 8.8 Hz,
δ 8.77 (s, 1H, H-4), 8.00 (d, J5,6
ꞌꞌꞌ,2ꞌꞌꞌ/5ꞌꞌꞌ,6
2H, H-3ꞌꞌꞌ,5ꞌꞌꞌ), 4.78 (s, 1H, H-5
DMSO-d6): 164.7, 159.3, 159.0, 158.2, 155.7, 154.6, 153.1, 141.2, 130.4, 128.8, 128.2, 127.7,
ꞌ
), 3.77 (s, 3H, OCH3), 1.22 (s, 9H, 3OCH3); 13C NMR (75 MHz,
δ
127.0, 127.0, 125.6, 125.3, 125.1, 125.1, 122.2, 122.2, 118.3, 116.0, 115.2, 115.2, 100.3, 55.7,
34.0, 31.2, 31.2, 31.2; Anal. Calcd for C30H27N3O4S, C = 68.55, H = 5.18, N = 7.99; Found C =
68.52, H = 5.15, N = 7.97; EI MS m/z (% rel. abund.): 523 (M+ , 6), 483 (62), 468 (9), 455 (11),
352 (34), 339 (75), 324 (100); HRMS (EI) calcd for C30H27N3O4S: m/z = 525.1722, found
525.1692.
(Z
)-4-Bromo-N-(2-((4-methoxyphenyl)imino)-4-(2-oxo-2H-chromen-3-yl)thiazol-3(2H)-
yl)benzamide (8)
Dark green solid; Yield: 77%; 1H-NMR (400 MHz, DMSO-d6):
H-4), 7.79 (m, 2H, H-3ꞌꞌ, 5ꞌꞌ), 7.58 (d, J5,6 = 8.4 Hz, 1H, H-5), 7.52 (m, 2H, H-2ꞌꞌꞌ, 6ꞌꞌꞌ), 7.33 (m,
δ 10.44 (s, 1H, NH), 8.76 (s, 1H,
3H, H-6, 7, 8), 7.05 (d, J2
ꞌꞌ = 8.8 Hz, 2H, H-2ꞌꞌ, 6ꞌꞌ), 6.95 (d, J3
ꞌꞌ = 8.8 Hz, 2H, H-3ꞌꞌ,5ꞌꞌ),
ꞌꞌ,2ꞌꞌ/5ꞌꞌ,6
ꞌꞌ,3ꞌꞌ/6ꞌꞌ,5
16

ACCEPTED MANUSCRIPT
13
4.80 (s, 1H, H-5
ꞌ
), 3.72 (s, 3H, OCH3); C NMR (75 MHz, DMSO-d6):
δ
164.7, 159.3, 159.0,
158.1, 155.7, 153.2, 141.1, 131.5, 131.5, 131.1, 130.4, 129.8, 129.8, 128.2, 127.7, 125.4, 126.3,
125.1, 122.3, 122.3, 118.2, 116.0, 115.1, 115.1, 100.2, 55.6; Anal. Calcd for C26H18BrN3O4S, C
= 56.94, H = 3.31, N = 7.66; Found C = 56.92, H = 3.34, N = 7.64; EI MS m/z (% rel. abund.):
547 (M+, 2), 549 (M+2, 2), 505 (23), 479 (5), 376 (19), 363 (50), 347 (22), 329 (37); HRMS (EI)
calcd for C26H18BrN3O4S: m/z = 547.0201, found 547.0192.
(Z
)-2-Hydroxy-
N-(2-((4-methoxyphenyl)imino)-4-(2-oxo-2H-chromen-3-yl)thiazol-3(2H)-
yl)benzamide (9)
Dark green solid; Yield: 80%; 1H-NMR (400 MHz, DMSO-d6):
H-4), 8.01 (d, J5,6 = 8.0 Hz, 1H, H-5), 7.80 (t, J7,6 = J7,8 = 7.6 Hz, 1H, H-7), 7.51 (d, J8,7 = 8.4 Hz,
1H, H-8), 7.46 (t, J6,5 = J6,7 = 7.6 Hz, 1H, H-6), 7.25 (m, 3H, H-2ꞌꞌ, 6ꞌꞌ, 4ꞌꞌꞌ), 7.11 (d, J6 = 7.6
δ 10.24 (s, 1H, NH), 8.77 (s, 1H,
ꞌꞌꞌ,5ꞌꞌꞌ
Hz, 1H, H-6ꞌꞌꞌ), 6.98 (d, J3
ꞌꞌ = 8.8 Hz, 2H, H-3ꞌꞌ, 5ꞌꞌ), 6.81 (d, J3 ꞌꞌꞌ = 8.0 Hz, 1H, H-3ꞌꞌꞌ), 6.77
ꞌꞌꞌ,4
ꞌꞌ,2ꞌꞌ/5ꞌꞌ,6
(d, J5
= J5
= 7.2 Hz, 1H, H-5ꞌꞌꞌ), 4.81 (s, 1H, H-5
ꞌꞌꞌ,6ꞌꞌꞌ
ꞌ
), 3.73 (s, 3H, OCH3); 13C NMR (75
ꞌꞌꞌ,4ꞌꞌꞌ
MHz, DMSO-d6):
δ 164.6, 159.3, 159.2, 159.0, 158.1, 155.7, 153.1, 141.4, 133.4, 130.3, 128.7,
128.5, 127.7, 125.8, 125.5, 122.0, 122.0, 121.2, 119.7, 118.3, 117.7, 116.2, 115.1, 115.1, 100.2,
55.9; Anal. Calcd for C26H19N3O5S, C = 64.32, H = 3.94, N = 8.65; Found C = 64.30, H = 3.91,
N = 8.63; EI MS m/z (% rel. abund.): 458 (M+ , 52), 443 (38), 415 (5), 312 (100), 299 (35), 266
(58); HRMS (EI) calcd for C26H19N3O5S: m/z = 485.1045, found 485.1036.
(
Z N-(2-((3-Bromophenyl)imino)-4-(2-oxo-2H-chromen-3-yl)thiazol-3(2H)-yl)-3,5-
)-
dimethoxybenzamide (10)
Dark green solid; Yield: 69%; 1H-NMR (500 MHz, DMSO-d6):
H-4), 8.03 (d, J5,6 = 8.0 Hz, 1H, H-5), 7.82 (t, J7,6 = J7,8 = 8.5 Hz, 1H, H-7), 7.53 (d, J8,7 = 8.5 Hz,
1H, H-8), 7.48 (t, J6,5 = J6,7 = 7.5 Hz, 1H, H-6), 7.25 (m, 3H, H-2ꞌꞌ, 6ꞌꞌ, 4ꞌꞌꞌ), 7.19 (d, J3 ꞌꞌ = 8.8
δ 10.20 (s, 1H, NH), 8.79 (s, 1H,
ꞌꞌ,2ꞌꞌ/5ꞌꞌ,6
Hz, 2H, H-3ꞌꞌ, 5ꞌꞌ), 7.16 (d, J6 ꞌꞌꞌ = 7.5 Hz, 1H, H-6ꞌꞌꞌ), 6.80 (m, 2H, H-3ꞌꞌꞌ, 5ꞌꞌꞌ), 4.85 (s, 1H, H-5ꞌ),
ꞌꞌꞌ,5
13
2.28 (s, 3H, CH3); C NMR (75 MHz, DMSO-d6):
δ 164.7, 159.3, 159.1, 158.5, 155.8, 153.1,
146.2, 136.7, 133.3, 130.6, 130.4, 130.4, 128.7, 128.1, 127.8, 125.9, 125.3, 121.2, 119.7, 119.7,
119.7, 118.2, 117.6, 116.2, 100.3, 21.5; Anal. Calcd for C27H20BrN3O5S, C = 56.06, H = 3.49, N
= 7.26; Found C = 56.04, H = 3.47, N = 7.29; EI MS m/z (% rel. abund.): 577 (M+ , 2), 579 (M+2
17

ACCEPTED MANUSCRIPT
, 1.8),451 (12), 436 (8), 360 (12); HRMS (EI) calcd for C27H20BrN3O5S: m/z = 577.0307, found
577.0301.
(
Z N-(2-((3-Bromophenyl)imino)-4-(2-oxo-2H-chromen-3-yl)thiazol-3(2H)-yl)-2-
)-
hydroxybenzamide (11)
Dark green solid; Yield: 75%; 1H-NMR (400 MHz, DMSO-d6):
H-4), 8.01 (d, J5,6 = 8.0 Hz, 1H, H-5), 7.80 (t, J7,6 = J7,8 = 7.6 Hz, 1H, H-7), 7.63 (m, 2H, H-2ꞌꞌ
ꞌꞌ), 7.51 (d, J8,7 = 8.4 Hz, 1H, H-8), 7.46 (t, J6,5 = J6,7 = 7.6 Hz, 1H, H-6), 7.41 (t, J4 ꞌꞌꞌ = 8.0 Hz,
δ 10.04 (s, 1H, NH), 8.76 (s, 1H,
,
4
ꞌꞌꞌ,3
1H, H-4ꞌꞌꞌ), 7.31 (d, J6 ꞌꞌꞌ = 8.4 Hz, 1H, H-6ꞌꞌꞌ), 7.26 (m, 2H, H-5ꞌꞌ, 6ꞌꞌ), 6.83 (d, J5 ꞌꞌꞌ = J5 ꞌꞌꞌ =7.6
ꞌꞌꞌ,5
ꞌꞌꞌ,4
ꞌꞌꞌ,6
Hz, 1H, H-5ꞌꞌꞌ), 6.79 (d, J3
= 8.4 Hz, 1H, H-3ꞌꞌꞌ), 4.83 (s, 1H, H-5ꞌ
); 13C NMR (75 MHz,
ꞌꞌꞌ,4ꞌꞌꞌ
DMSO-d6):
δ 164.6, 159.3, 159.0, 158.4, 155.7, 153.2, 151.1, 133.7, 130.4, 130.1, 128.8, 128.4,
127.8, 125.6, 125.2, 125.0, 123.7, 123.2, 121.5, 121.3, 119.7, 118.2, 117.9, 116.3, 100.2; Anal.
Calcd for C25H16BrN3O4S, C = 56.19, H = 3.02, N = 7.86; Found C = 56.17, H = 3.04, N = 7.89;
EI MS m/z (% rel. abund.): 533 (M+ , 25), 535 (M+2, 27), 493 (7), 386 (6), 362 (19), 347 (100),
317 (5); HRMS (EI) calcd for C25H16BrN3O4S: m/z = 533.0045, found 533.0027.
(
Z N-(2-((3,4-Dichlorophenyl)imino)-4-(2-oxo-2H-chromen-3-yl)thiazol-3(2H)-yl)-2,4-
)-
dimethoxybenzamide (12)
Dark green solid; Yield: 68%; 1H-NMR (400 MHz, DMSO-d6):
H-4), 7.93 (d, J2 = 2.4 Hz, 1H, H-2ꞌꞌ), 7.68 (d, J6
δ
10.92 (s, 1H, NH), 8.82 (s, 1H,
= 8.4 Hz, 2H, H-6ꞌꞌ, 6ꞌꞌꞌ), 7.61 (d,
ꞌꞌ,5ꞌꞌ/6ꞌꞌꞌ,5ꞌꞌꞌ
ꞌꞌ,6ꞌꞌ
J5
= 8.8 Hz, 2H, H-5ꞌꞌ, 5ꞌꞌꞌ), 7.51 (m, 3H, H-5, 7, 8), 6.74 (bd.s, 1H, H-3ꞌꞌꞌ), 6.70 (d, J6,5 =
ꞌꞌ,6ꞌꞌ/5ꞌꞌꞌ,6ꞌꞌꞌ
8.0 Hz, 1H, H-6), 4.88 (s, 1H, H-5
MHz, DMSO-d6): 164.6, 163.1, 159.5, 158.2, 155.8, 153.2, 148.4, 136.6, 131.7, 131.6, 131.0,
ꞌ
), 3.88 (s, 3H, OCH3), 3.84 (s, 3H, OCH3); 13C NMR (75
δ
130.6, 129.6, 128.4, 127.8, 125.6, 125.5, 120.7, 120.6, 118.3, 116.2, 110.4, 110.2, 100.2, 98.4,
55.8, 55.6; Anal. Calcd for C27H19Cl2N3O5S, C = 57.05, H = 3.37, N = 7.39; Found C = 57.07, H
= 3.34, N = 7.41; EI MS m/z (% rel. abund.): 538 (M+-OMe, 2), 388 (12), 365 (43), 313 (35);
HRMS (EI) calcd for C27H19Cl2N3O5S: m/z = 567.0422, found 567.0418.
18

ACCEPTED MANUSCRIPT
(Z
)-4-(tert-Butyl)-N-(2-((3,4-dichlorophenyl)imino)-4-(2-oxo-2
H
-chromen-3-yl)thiazol-
3(2 )-yl)benzamide (13)
H
Dark green solid; Yield: 65%; 1H-NMR (400 MHz, DMSO-d6):
1H, H-2ꞌꞌ), 7.84 (d, J2
δ
11.10 (s, 1H, NH), 7.95 (bd.s,
= 8.0 Hz, 2H, H-2ꞌꞌꞌ, 6ꞌꞌꞌ), 7.68 (m, 9H, H-4, 5, 6, 7, 8, 5ꞌꞌ, 6ꞌꞌ, 3ꞌꞌꞌ
,
ꞌꞌꞌ,3ꞌꞌꞌ/6ꞌꞌꞌ,5ꞌꞌꞌ
5
ꞌꞌꞌ), 4.81 (s, 1H, H-5
ꞌ
), 1.31 (s, 9H, 3CH3); 13C NMR (75 MHz, DMSO-d6):
δ
164.7, 159.5,
158.4, 155.7, 154.8, 153.2, 148.6, 131.7, 131.6, 131.2, 130.6, 128.7, 128.2, 127.8, 127.2, 127.2,
125.7, 125.5, 125.2, 125.2, 120.5, 120.3, 118.3, 116.0, 100.2, 34.1, 31.4, 31.4, 31.4; Anal. Calcd
for C29H23Cl2N3O3S, C = 61.71, H = 4.11, N = 7.44; Found C = 61.74, H = 4.13, N = 7.42; EI
MS m/z (% rel. abund.): 563 (M+ , 2), 565 (M+2, 2), 405 (9), 390 (19), 362 (35), 346 (17), 330
(26), 218 (35); HRMS (EI) calcd for C29H23Cl2N3O3S: m/z = 563.0837, found 563.0834.
(
Z N-(2-((3,4-Dichlorophenyl)imino)-4-(2-oxo-2H-chromen-3-yl)thiazol-3(2H)-yl)-2-
)-
hydroxybenzamide (14)
Dark green solid; Yield: 70%; 1H-NMR (400 MHz, DMSO-d6):
H-4), 8.00 (d, J5,6 = 7.2 Hz, 1H, H-7), 7.80 (t, J7,6 = J7,8 = 7.2 Hz, 1H, H-7), 7.71 (m, 2H, H-2ꞌꞌ
δ 9.98 (s, 1H, NH), 8.76 (s, 1H,
,
6
ꞌꞌ), 7.51 (d, J8,7 = 8.4 Hz, 1H, H-8), 7.46 (t, J5,6 = 7.6 Hz, 1H, H-5), 7.30 (m, 3H, H-5ꞌꞌ, 4ꞌꞌꞌ, 6ꞌꞌꞌ),
6.86 (t, J5 ꞌꞌꞌ = J5 ꞌꞌꞌ =7.2 Hz, 1H, H-5ꞌꞌꞌ), 6.77 (d, J3 ꞌꞌꞌ = 8.4 Hz, 1H, H-3ꞌꞌꞌ), 4.81 (s, 1H, H-5ꞌ);
ꞌꞌꞌ,4
ꞌꞌꞌ,6
ꞌꞌꞌ,4
13C NMR (75 MHz, DMSO-d6):
δ 164.8, 159.5, 159.3, 158.2, 155.7, 153.1, 148.4, 133.6, 131.8,
131.4, 131.0, 130.6, 128.8, 128.4, 127.9, 125.6, 125.3, 121.5, 120.7, 120.4, 119.7, 118.0, 117.8,
116.2, 100.2; Anal. Calcd for C25H15Cl2N3O4S, C = 57.26, H = 2.88, N = 8.01; Found C = 57.23,
H = 2.86, N = 8.03; EI MS m/z (% rel. abund.): 523 (M+ , 37), 495 (7), 481 (25), 453 (6), 350
(90), 337 (53), 304 (58), 288 (12); HRMS (EI) calcd for C25H15Cl2N3O4S: m/z = 523.0160, found
523.0152.
Acknowledgements: The authors are thankful to Higher Education Commission (HEC)
Pakistan, for funding to Project No. 20-1910 under the National Research Program for
Universities.
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Research Highlights
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
Synthesis of new 3-thiazolylcoumarin
Hybrid of thiazole and coumarin
α-Glucosidase inhibitory properties
Molecular docking studies were carried out
Useful in diabetic complications