Pyrazolobenzothiazine-based carbothioamides as new structural leads for the inhibition of monoamine oxidases: design, synthesis, in vitro bioevaluation and molecular docking studies

Article abstract of DOI:10.1039/c6md00570e

Two new series of pyrazolobenzothiazine-based carbothioamides (3a-o and 4a-o) were synthesized using saccharin as the starting material. The synthesized derivatives were investigated for their ability to inhibit monoamine oxidases (MAO). Compound 3b was found to be a very potent MAO-A inhibitor with an IC₅₀ value of 0.003 ± 0.0007 μM, while compound 4d was the most effective inhibitor of MAO-B having an IC₅₀ value of 0.02 ± 0.001 μM. Molecular docking studies were performed to identify the probable binding modes in the active site of the monoamine oxidase enzymes. The synthetic and computational investigations in the current work suggested that these newly identified inhibitors may serve as a powerful starting point for the exploration and optimization of potential therapeutic agents targeting Parkinson's disease.

Full text of DOI:10.1039/c6md00570e

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Pyrazolobenzothiazine-based carbothioamides as new structural leads for the inhibition
of monoamine oxidases: design, synthesis, in-vitro bioevaluation and molecular docking
studies‡
Syed Mobasher Ali Abid†a, Sana Aslam†b,c, Sumera Zaiba, Syeda Mahwish Bakhta, Matloob
Ahmadd, Muhammad Makshoof Atharc, John M Gardinere,*, Jamshed Iqbala,*
aCentre for Advanced Drug Research, COMSATS Institute of Information Technology,
Abbottabadꢀ22060, Pakistan.
bDepartment of Chemistry, Government College Women University, Faisalabadꢀ38000,
Pakistan.
cInstitute of Chemistry, University of the Punjab, Lahore, Pakistan.
dDepartment of Chemistry, Government College University, Faisalabadꢀ38000, Pakistan.
eSchool of Chemistry and Manchester Institute of Biotechnology, University of Manchester,
Manchester M1 7DN, UK.
†These authors contributed equally to this work.
‡The authors declare no competing interests.
*Correspondence address:
Tel.: +44 161 306 4530 (J.M. Gardiner); Tel: +92 992 383591 96; Fax: +92 992 383441 (J.
Iqbal)
Eꢀmail address: gardiner@manchester.ac.uk (J.M. Gardiner); drjamshed@ciit.net.pk;
jamshediqb@googlemail.com (J. Iqbal)
Abstract
Two new series of pyrazolobenzothiazineꢀbased carbothioamides (3a-o) and (4a-o) were
synthesized using saccharine as starting material. Synthesized derivatives were investigated
for their ability to inhibit monoamine oxidases (MAO). Compound 3b was found to be a very
potent MAOꢀA inhibitor with an IC50 value of 0.003 ± 0.0007 µM, while, compound 4d was
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the most effective inhibitor of MAOꢀB having an IC50 value of 0.02 ± 0.001 µM. Molecular
docking studies were performed to identify the probable binding modes in the active site of
the monoamine oxidase enzymes. The synthetic and computational investigations in the
current work suggested that these newly identified inhibitors may serve as a powerful starting
point for the exploration and optimization of potential therapeutic agents targeting
Parkinson’s disease.
Keywords:
Carbothioamides,
Monoamine
oxidases,
Molecular
docking,
Pyrazolobenzothiazine.
Introduction
Parkinson’s disease (PD), a progressive neurodegenerative disorder, is considered as the
second most prevelant disease after Alzheimer’s disease affecting up to 10 million people
throughout the world.1 These neurodegenerative disorders are mainly characterized by motor
and nonꢀmotor symptoms such as depression and anxiety etc.2 Although a significant volume
of research has generated numerous chemical entities for the treatment of motor related
symptoms of PD, decline in dopamine level in neuronal synapses still subsists. Therefore,
dopaminergic agonists are thought to play a crucial role in the therapy of PD.1,2
Monoamine oxidase (MAO; EC 1.4.3.4) is a flavoenzyme responsible for the metabolism and
regulation of neurotransmitters such as 5ꢀhydroxytryptamine, norepinephrine and dopamine
in the central nervous system.3 MAO is located in the outer mitochondrial membranes of
neuronal, glial cells4 particularly abundant in the liver and brain.5 The two main
classifications (MAOꢀA and MAOꢀB) of these isozymes having differentiated substrate
specificity, different amino acid sequences and differing sensitivity to inhibitors have been
recognized. MAOꢀA preferentially oxidizes biogenic amines such as norepinephrine and
serotonine, whereas MAOꢀB plays its critical role in the deamination of βꢀphenylethylamine.
2

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A range of structurally diverse heterocyclic compounds including pyrrolylꢀoxazolidinones,
triazolothiadiazoles, triazolothiadiazines, thiazolylhydrazones, piperidylꢀthienyl chalcones
and their 2ꢀpyrazoline derivatives have been reported to inhibit monoamine oxidases.2,6ꢀ9 The
adverse side effects posed by these MAOꢀinhibitors in clinics means there is an urgent need
to develop potent bioactive inhibitors having fewer side effects and better activity.
Thiosemicarbazones of αꢀ(N)ꢀheterocyclic aldehydes or ketones have been demonstrated as
potent biologicallyꢀactive compounds. In the past few years, various derivatives of this family
have been reported to possess antibacterial,10 antiviral,11 antimalarial12,13 and anticancer14
activities. The structureꢀactivity relationship (SAR) data revealed that the substitution at Nꢀ
(4) of the thiosemicarbazone fragment as well as at the parent aldehyde or ketone is of key
importance to the extent and type of biological activity.15
In the current study to explore new structural fragments for the inhibition of monoamine
oxidases, we focused on the pyrazolobenzothiazine core. This heterocyclic motif is an
intriguing scaffold for the discovery of new chemical entities (NCEs) for pharmacotherapy,
evidenced by examples with significant potential as potent antiꢀinflammatories, analgesics,16
antiꢀdepressants17 and as selective focal adhesion kinase (FAK) inhibitors18 in addition to
HCV replication inhibitors.19 Thiopheneꢀbased pyrazoline derivatives having
a
carbothioamide tail were found to offer potential as antidepressants.20 Recently, we have
reported new pyrazolobenzothiazine derivatives showing potential as antiꢀHIV agents21 and
as antioxidants.22ꢀ24 These literature precedents led us to target new analogues having a
carbothioamide side chain. We speculated that the extended side chain could potentially
modulate the inhibitory activity by helping the target compound to reside in the active pocket
of the enzyme. With this aim, and in continuation of our previous reports on the identification
of MAO inhibitors,7,9 the synthetic derivatives were screened for their monoamine oxidase
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inhibition. The detailed SAR studies with the help of molecular docking have also been
evaluated and are described here.
Results and discussion
Chemistry
The synthetic approach to new carbothioamides 3a-o and 4a-o is depicted in Scheme 1. The
key precursor compounds 1a and 1b were prepared from sodium saccharin according to our
previously reported methods.21,22,24,25 Specifically, Nꢀalkylation of commercial saccharin
sodium salt with suitable alkyl halides in Dimethylformamide (DMF)22, ring expansion to
benzothiazine ring systems, Nꢀmethylation and finally construction of pyrazole ring on
benzothiazine by cyclization with hydrazine hydrate provides the respective pyrazolo[4,3ꢀ
c][1,2]benzothiazine 5,5ꢀdioxide scaffolds (1a and 1b). We have already reported the
characterization of 1a and 1b by spectroscopic methods as well as by Xꢀray
crystallography.26, 27
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Scheme 1. Synthetic route for the synthesis of pyrazolobenzothiazineꢀbased carbothioamides
(3a-o) and (4a-o)
The Nꢀarylated key intermediates (2a) and (2b) were delivered as single regioisomers by
treating compounds 1a and 1b, respectively, with 4ꢀfluorobenzaldehyde under mild base
phase transfer conditions. The absorption peaks at 1727 and 1737 cmꢀ1 in the IR spectra in
compounds 2a and 2b, respectively, and singlets at the chemical shift values of 10.03 and
1
10.23 ppm respectively in the H NMR spectra, confirmed the introduction of the formyl
moiety.
Finally, the title carbothioamides 3a-o and 4a-o were prepared by the condensation reaction
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of compounds 2a and 2b with a series of diverse thiosemicarbazides in alcoholic media in the
presence of 0.3 mL of glacial acetic acid (Scheme 1). The reactions proceeded to completion
in 30ꢀ45 min affording a wide range of derivatives 3a-o and 4a-o in 80ꢀ90% yields (Table 1).
All the final compounds were fullyꢀcharacterized by spectroscopic techniques. The IR spectra
of compounds 3a-o and 4a-o showed characteristic CH=N absorbance in the region of 1593ꢀ
1603 and 1597ꢀ1627 cmꢀ1, respectively, C=S absorption in the 1150ꢀ1169 and 1157ꢀ1182 cmꢀ
1 regions and NꢀH stretches were observed at 3270ꢀ3349 and 3310ꢀ3350 cmꢀ1, respectively.
1
The H NMR spectra showed singlet peaks in the range of 10.2ꢀ10.3 and 11.9ꢀ12.1 ppm for
the protons of =NꢀNH and NH groups of thiosemicarbazone moiety. For compounds 3n and
4n, NH peaks were observed as a triplet at 9.27 and 8.55 ppm, respectively and the =CꢀH
proton was observed at 8.22ꢀ8.25 ppm. The 13C NMR spectra also fully supported
assignments with carbons of the C=S group observed at 175.9ꢀ177.7 ppm.
Table 1. Synthesis of pyrazolobenzothiazineꢀbased carbothioamides (3a-o) and (4a-o)
Entry
Products
3a
R1
Reaction Time (min)
Yield (%)
1
2ꢀmethylphenyl
36
87
2
3
4
5
4ꢀmethylphenyl
phenyl
35
30
32
37
89
84
85
82
3b
3c
3d
3e
4ꢀethylphenyl
2,4ꢀdimethylphenyl
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6
2,6ꢀdimethylphenyl
40
31
34
31
32
33
34
41
45
31
40
41
40
38
39
41
42
40
41
37
38
40
38
44
38
90
85
83
89
87
88
82
83
80
86
87
84
81
85
81
87
83
84
85
83
84
82
84
81
89
3f
3g
3h
3i
7
2ꢀchlorophenyl
3ꢀchlorophenyl
4ꢀchlorophenyl
2ꢀfluorophenyl
3ꢀfluorophenyl
4ꢀfluorophenyl
benzyl
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
3j
3k
3l
3m
3n
3o
4a
4b
4c
4d
4e
4f
methylmorpholine
H
2ꢀmethylphenyl
4ꢀmethylphenyl
phenyl
4ꢀethylphenyl
2,4ꢀdimethylphenyl
2,6ꢀdimethylphenyl
2ꢀchlorophenyl
3ꢀchlorophenyl
4ꢀchlorophenyl
2ꢀfluorophenyl
3ꢀfluorophenyl
4ꢀfluorophenyl
benzyl
4g
4h
4i
4j
4k
4l
4m
4n
4o
methylmorpholine
H
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Monoamine oxidase inhibition
The inꢀvitro monoamine oxidase (A and B) inhibitory activity of 2ꢀ(4ꢀ(3,4ꢀdimethyl/4ꢀ
methylꢀ3ꢀphenylꢀ5,5ꢀdioxidobenzo[e]pyrazolo[4,3ꢀc][1,2]thiazinꢀ2(4H)ꢀyl)benzylidene)ꢀNꢀ
phenylꢀhydrazine carbothioamides 3a-o and 4a-o was assayed using standard methods.7,28
After the initial screening of these compounds, IC50 values were calculated for derivatives
which showed >50% inhibition (Table 2). Clorgyline and deprenyl were used as standard
inhibitors with IC50 values of 0.0045 ± 0.0003, 0.0196 ± 0.001 µM, respectively.
In the 3a-o series, compounds 3a, 3b and 3f exhibited selective inhibition of MAOꢀA as
compared to MAOꢀB. For the series 4a-o, approximately half of the tested compounds
showed better selectivity for MAOꢀB with five compounds showng subꢀmicromolar IC50
values. Compound 3b, containing 4ꢀmethylphenyl as R1, was the most potent inhibitor of
MAOꢀA depicting an IC50 value of 0.003 ± 0.0007 µM which is ~1.5ꢀfold higher inhibition as
compared to standard inhibitor, clorgyline (IC50 = 0.0045 ± 0.0003 µM). Compounds 3a and
3f also exhibited good inhibition with IC50 values of 0.01 ± 0.0005 µM. Notably, 3a has a 2ꢀ
methylphenyl R1 unit, whereas, 3f has 2,6ꢀdimethylphenyl substituent. Compound 3e, having
R1 = 2,4ꢀdimethylphenyl, also retained a significant IC50 value (1.13 ± 0.001 µM). These data
indicate that methylphenyl and dimethylphenyl derivatives may be more potent and selective
inhibitors towards MAOꢀA, all showing 2ꢀ4 orders of magnitude selectivity for MAOꢀA over
MAOꢀB inhibition. When the weakly electronꢀdonating methyl group was replaced with an
electronꢀwithdrawing halogen substituent such as chlorine and fluorine in 3a-o series,
somewhat different results were observed. For 3ꢀchloro/flouro substitutions (3h and 3k), the
high inhibitory values were noticed compared to other halogenated analogues.
Among the 4a-oseries, compound 4j having 2ꢀfluorophenyl and 4o having thiosemicarbazide
groups were the only subꢀmicrolmolar inhibitors of MAOꢀA with IC50 values of 0.54 ± 0.006
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and 0.97 ± 0.07 µM, respectively. Notably, for the 4a-o series, a number of compounds (i.e.
4d-g and 4m) showed 1ꢀ2 orders of magnitude selelctivity for MAOꢀB. The most active
compound in the series was 4d, having an IC50 value of 0.02 ± 0.001 µM, against MAOꢀB
which is comparable to the reference deprenyl (IC50 = 0.0196 ± 0.001 µM). Other compounds
in the series, which showed the potent inhibitory activity, were 4e-g and 4m, all with IC50
values in the subꢀmicromolar range.
Table 2. Monoamine oxidase inhibition of pyrazolobenzothiazineꢀbased carbothioamides
(3a-o) and (4a-o)
Compound
MAO-A
IC50 ± SEM (µM)
MAO-B
0.01 ± 0.0005
0.003 ± 0.0007
3.69 ± 0.04
1.77 ± 0.03
1.13 ± 0.001
0.01 ± 0.0005
4.06 ± 0.07
1.11 ± 0.003
3.49 ± 0.05
1.42 ± 0.004
0.47 ± 0.007
30.2 ± 5.02
76.2 ± 7.31
64.8 ± 5.28
31.2 ± 4.07
NDb
3.13 ± 0.14
29.5 ± 4.68
4.15 ± 0.57
2.91 ± 0.04
0.11 ± 0.005
6.11 ± 0.07
6.21 ± 0.09
2.89 ± 0.07
0.43 ± 0.006
3.83 ± 0.03
1.68 ± 0.005
41%a
3a
3b
3c
3d
3e
3f
3g
3h
3i
3j
3k
3l
4.72 ± 0.38
4.34 ± 0.06
36%a
3m
3n
3o
4a
4b
4c
4d
4e
NDb
NDb
NDb
27.2 ± 3.62
8.18 ± 1.94
9.15 ± 2.04
2.49 ± 0.03
0.02 ± 0.001
0.75 ± 0.004
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65.7 ± 7.91
33.8 ± 4.62
7.73 ± 0.16
2.06 ± 0.01
0.54 ± 0.006
9.02 ± 0.08
2.33 ± 0.03
10.6 ± 1.01
3.07 ± 0.19
0.97 ± 0.07
0.0045 ± 0.0003
67.25 ± 1.02
0.77 ± 0.005
0.68 ± 0.003
20.9 ± 2.74
3.27 ± 0.04
19%a
4f
4g
4h
4i
4j
1.76 ± 0.008
6.99 ± 0.05
0.64 ± 0.007
2.99 ± 0.06
2.39 ± 0.05
61.35 ± 1.13
0.0196 ± 0.001
4k
4l
4m
4n
4o
Clorgyline
Deprenyl
a: % inhibition at 100 µM end concentration; bND: Not determined
Molecular Docking
The AutoDock 4.2 program was used for automated molecular docking. Docking validation
was carried out by reꢀdocking the ligand extracted from the experimentally determined
enzymeꢀligand adduct. To rationalize the obtained inꢀvitro biological results, molecular
docking study was performed against human MAOꢀA (PDB ID: 2Z5Y) and MAOꢀB (PDB
ID: 2V5Z). The binding pattern of synthesized inhibitors was established by molecular
docking studies. The docking method was able to reproduce the experimentally observed
bound conformation of the coꢀcrystallized ligand with rmsd <2 Å. By reꢀdocking the
crystallographic ligand harmine (HRM) in the active site of MAOꢀA, similar interactions
were seen with the residues Tyr407 as HRM showed in the crystal structure of MAOꢀA.
Similarly, safinamide was reꢀdocked in the active site of MAOꢀB and interactions were found
with residues Tyr435 and Tyr398. The original coꢀcrystallized carboline ligand (7ꢀmethoxyꢀ
1ꢀmethylꢀ9Hꢀbetaꢀcarboline, HRM), with MAOꢀA (PDB ID: 2Z5Y) was also πꢀstacked
against Tyr407. FAD coenzyme was oriented towards either side by Tyr407 and Tyr444
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residues in MAOꢀA. For inhibition of MAOꢀA, this πꢀinteraction with one or both of the
tyrosine residues (Tyr407 and Tyr444) appeared to be important.29 Important van der Waals
interactions were detected for reference ligands HRM with residues Tyr69, Ile180, Phe208,
Val210, Ile335, Phe352 and Tyr444. Polar interactions were observed with the coenzyme
FAD and residues Tyr407, Cys323 and Gln215.
Figure 1. Putative binding mode of inhibitor 3b (carbon atoms colored green) and the
crystallographic inhibitor harmine (carbon atoms colored pink) in the active site of MAOꢀ
A.
The docking studies of the most potent compound 3b against MAOꢀA was carried out to gain
further structural insights of the binding mode and possible interactions with the active site of
the enzyme. The 4ꢀmethylphenyl moiety of 3b was oriented deep towards FAD and residues
Tyr407 and Tyr444 forming πꢀstacked interactions, whereas the benzothiazine ring was
oriented in the hydrophobic pocket of the active site. Figure 1 shows overlay of binding mode
of this potent compound as well as cognate ligand within the active site of MAOꢀA. The van
der Waals interactions were observed with residues Ile325, Ile335, Phe352, Tyr69 and
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Tyr197. Polar interactions were observed with coenzyme FAD and residues Tyr407, Gln215,
Val210, Phe208, Ile180, and Cys323.
In case of MAOꢀB, in vitro results evidenced that 4d was the most suitable compound for
docking studies. Before docking the potent inhibitor, in the active site of MAOꢀB enzyme,
molecular docking studies of coꢀcrystallized ligand safinamide (S)ꢀ(+)ꢀ2ꢀ[4ꢀ
(fluorobenzyloxyꢀbenzylamino)propionamide] were performed. The ligand was reproduced
successfully with an RMSD value of 2.0 Å. For MAOꢀB docking analysis, the
phenylbenzothiazine ring of 4d was found to be oriented towards the FAD molecule in the
substrate cavity of the enzyme and πꢀstacked against Tyr398 and Tyr435 residues. These
interactions were found important for MAOꢀB inhibition.30 The similar interactions were
observed by coꢀcrystallized ligand safinamide (SAG). Figure 2 shows an overlay of binding
mode of potent compound as well as safinamide in the active site of MAOꢀB. The van der
Waals interactions were observed for SAG with residues with Gln206, Cys172, Ile198,
Tyr326, and Ile199. The coenzyme FAD and residue Phe168 showed polar interactions. The
fluorobenzyl moiety of safinamide was noted to be orientated more towards entrance cavity,
and similarly, the ethyphenyl side chain of 4d was oriented towards the entrance cavity.
Moreover, 4d showed important van der Waals interactions with residues Phe103, Leu164,
Phe168, Ile199, Tyr326 and Phe343. Apart from πꢀπ interactions with the Tyr398 and
Tyr435, FAD and residues Gln206 and Ile316 showed polar interactions with 4d. The
molecular docking studies gave rise to hypothesis that there is a crucial correlation between
the inhibitory activity and the aryl substituents attached and their ring position.
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Figure 2. Putative binding mode of inhibitor 4d (carbon atoms colored green) and the
crystallographic inhibitor safinamide (carbon atoms colored pink) in the active site of
MAOꢀB.
Conclusion
This work reports the synthesis of two series of novel pyrazolobenzothiazineꢀbased
carbothioamides and their evaluation as inhibitors of monoamine oxidase A and B to identify
new potent leads against both MAOꢀA and MAOꢀB. The compound 3b was found to be a
very potent selective MAOꢀA inhibitor with an IC50 value of 0.003 ± 0.0007 µM, whereas,
compound 4d was the most effective selective inhibitor against MAOꢀB having an IC50 value
of 0.02 ± 0.001 µM. The data suggested that addition of various methylphenyl groups as a
substituent of pyrazolobenzothiazineꢀbased carbothioamide may lead to an enhanced
inhibition for MAOꢀA. In addition to enzymatic evaluation, the computational analysis of the
enzymeꢀinhibitor interaction energy of each derivative revealed plausible putative binding
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modes of the extended structure of 3b and 4d along with the active sites of MAOꢀA and
MAOꢀB. Our observations may set a platform for future investigations in the design of better
and selective MAO inhibitors.
Experimental
All the chemicals were purchased from E. Merck, Sigma/Aldrich or Fluka and used without
purification. General melting points were obtained on Gallenkamp melting point apparatus
and were uncorrected. IR spectra were recorded as KBr pellets on Perkin Elmer infrared
1
spectrophotometer. H NMR spectra were recorded in DMSOꢀd6 on Bruker/XWIN NMR
(300 and 400 MHz) and TMS was used as an internal standard (chemical shifts, δ in ppm).
Mass spectra were recorded on a Jeol MS Route instrument. Ultrasonic mediated reactions
were carried out in Clifton Ultrasonic Bath (2 9 T2A, 300W, DUꢀ4) made by Nickel Electro
Ltd.
General procedure for the synthesis of 4-(3,4-dimethyl-5,5-dioxidobenzo[e]pyrazolo[4,3-
c][1,2]thiazin-2(4H)-yl)benzaldehyde (2a) and 4-(4-methyl-5,5-dioxido-3-phenylbenzo[e]
pyrazolo[4,3-c][1,2]thiazin-2(4H)-yl)benzaldehydes (2b)
3,4ꢀDimethylꢀ2,4ꢀdihydropyrazolo[4,3ꢀc] [1,2]benzothiazine 5,5ꢀdioxide (1a) (12.50 g; 50.0
mmol) or 4ꢀmethylꢀ3ꢀphenylꢀ2,4ꢀdihydrobenzo[e]pyrazolo[4,3ꢀc][1,2]thiazine 5,5ꢀdioxide
(1b) (15.55 g; 50.0 mmol), 4ꢀfluorobenzaldehyde (7.44 g; 60.0 mmol) and anhydrous K2CO3
(8.30 g; 60.0 mmol) were dissolved in anhydrous DMF (25 mL) followed by the addition of
hexadecyltriphenylphosphonium bromide (2.54 g; 5.0 mmol). The reaction mixture was
refluxed under the nitrogen atmosphere for 40 min. Iceꢀcold water was added and the
resulting paleꢀyellow precipitates were filtered, washed with excess water and recrystallized
from ethanol.
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4-(3,4-Dimethyl-5,5-dioxidobenzo[e]pyrazolo[4,3-c][1,2]thiazin-2(4H)-yl)benzaldehyde
(2a)
º
Pale offꢀyellow solid; yield: 75%. m.p: 231 C; FTꢀIR (KBr) cmꢀ1: 3097, 2994, 2927, 2836,
1
2771, 1727, 1598, 1445, 1359, 1244, 1161, 821, 725; H NMR (DMSO, 300 MHz) δ: 2.49
(3H, s, CH3), 3.09 (3H, s, NꢀCH3), 7.52 (1H, t, J=7.5 Hz, ArꢀH), 7.64 (2H, d, J=6.3 Hz, Arꢀ
H), 7.67 (2H, d, J=6.4 Hz, ArꢀH), 7.91 (1H, d, J=6.6 Hz, ArꢀH), 7.95 (1H, d, J=8.4 Hz, Arꢀ
H), 8.04 (1H, d, J=7.2 Hz, ArꢀH), 10.03 (1H, s, CH); 13C NMR (DMSOꢀd6, 75 MHz) δ: 11.0
(CꢀCH3), 40.0 (NꢀCH3), 124.3 (ArꢀC), 124.8 (ArꢀC), 124.9 (2C) (ArꢀC), 125.5 (ArꢀC), 127.8
(ArꢀC),129.3 (2C) (ArꢀC), 130.9 (ArꢀC), 132.6 (ArꢀC), 133.0 (ArꢀC), 133.6 (ArꢀC), 135.5
(ArꢀC), 139.7 (ArꢀC), 144.0 (N=C, ArꢀC), 190.9 (ꢀHC=O); MS m/z: (ESꢀ) 353 (M+), (ES+)
354.1 (M + H+); HRꢀMS(ES+): calcd for C18H16N3O3S (M+H+), 354.0912; found, 354.0907.
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4-(4-Methyl-5,5-dioxido-3-phenylbenzo[e]pyrazolo[4,3-c][1,2]thiazin-2(4H)-
yl)benzaldehyde (2b)
Pale offꢀyellow solid; yield: 70%; FTꢀIR (KBr) cmꢀ1: 3079, 2987, 2847, 2779, 1737, 1701,
1
1598, 1456, 1362, 1204, 1162, 824, 723; H NMR (DMSOꢀd6, 300 MHz) δ: 3.23 (3H, s, Nꢀ
CH3), 7.43ꢀ7.57 (2H, m, ArꢀH), 7.67 (1H, t, J=7.5 Hz, ArꢀH), 7.75ꢀ7.83 (4H, dd, J1=9.0 Hz,
J2=15.4 Hz, ArꢀH), 7.91 (1H, d, J=7.8 Hz, ArꢀH), 7.99 (2H, d, J=7.2 Hz, ArꢀH), 8.01 (2H, d,
J=7.2 Hz, ArꢀH), 8.13 (1H, d, J=7.2 Hz, ArꢀH), 10.23 (1H, s, CH); 13C NMR: (DMSOꢀd6, 75
MHz) δ: 38.7 (NꢀCH3), 124.3 (2C) (ArꢀC), 124.7 (ArꢀC), 125.1 (ArꢀC), 125.2 (ArꢀC), 126.9
(ArꢀC), 127.1 (ArꢀC), 127.8 (ArꢀC),128.3 (ArꢀC), 129.2 (ArꢀC), 129.4 (ArꢀC), 129.9 (2C)
(ArꢀC), 130.5 (ArꢀC), 131.0 (ArꢀC), 133.3 (ArꢀC), 135.6 (ArꢀC), 137.9 (ArꢀC), 139.1 (ArꢀC),
140.2 (ArꢀC), 143.0 (N=C, ArꢀC), 191.0 (ꢀHC=O); MS m/z: 416.1 (ES+, M+H+); HRꢀ
MS(ES+): calcd for C23H18N3O3S (M + H+), 416.1069; found, 416.1064.
Synthesis of pyrazolobenzothiazine-based carbothioamides (3a-o) and (4a-o)
4ꢀ(3,4ꢀDimethylꢀ5,5ꢀdioxidobenzo[e]pyrazolo[4,3ꢀc][1,2]thiazinꢀ2(4H)ꢀyl)benzaldehyde (2a)
or 4ꢀ(4ꢀmethylꢀ5,5ꢀdioxidoꢀ3ꢀphenylbenzo[e]pyrazolo[4,3ꢀc][1,2]thiazinꢀ2(4H)ꢀyl)benzaldꢀ
ehyde (2b) and various thiosemicarbazides were added in equimolar quantity in ethanol
followed by the addition of 0.3ꢀ0.5 mL of glacial acetic acid. Then, the reaction mixture was
allowed to reflux for 1 to 3 h depending on the reactivity of 4ꢀphenylthiosemicarbazides. The
resulting precipitates were filtered and washed with hot methanol and dried.
2-(4-(3,4-Dimethyl-5,5-dioxidobenzo[e]pyrazolo[4,3-c][1,2]thiazin-2(4H)-yl)benzylidene)
-N-(o-tolyl)hydrazinecarbothioamide (3a)
Offꢀwhite powder; m.p.: 197 ºC; FTꢀIR (KBr) cmꢀ1: 3272, 3021, 2978, 2923, 1601, 1469,
1
1377, 1326, 1150, 1069, 970, 850,737; H NMR (DMSOꢀd6, 400 MHz) δ: 2.26 (3H, s, Cꢀ
CH3), 2.46 (3H, s, CꢀCH3), 3.05 (3H, s, NꢀCH3), 7.22 (2H, dd, J1=3.6 Hz, J2=6.8 Hz, ArꢀH),
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7.26ꢀ7.30 (3H, m, ArꢀH), 7.71 (2H, d, J=8.8 Hz, ArꢀH), 7.84 (1H, dt, J1=12 Hz, J2=7.6 Hz,
J3=15.6 Hz, ArꢀH), 7.95 (1H, d, J=7.2 Hz, ArꢀH), 8.07 (1H, d, J=8.0 Hz, ArꢀH), 8.14 (2H, d,
J=8.4 Hz, ArꢀH), 8.23 (1H, s, CH), 10.13 (1H,s,NH), 11.94 (1H,s,NH); 13C NMR (DMSOꢀd6,
100 MHz) δ: 10.3 (CꢀCH3), 17.8 (CꢀCH3), 39.2 (NꢀCH3), 115.1 (ArꢀC), 115.4 (ArꢀC), 123.8
(ArꢀC), 124.0 (ArꢀC), 124.5 (ArꢀC), 124.7 (ArꢀC), 125.9 (ArꢀC), 126.8 (ArꢀC), 127.3 (ArꢀC),
128.4 (ArꢀC), 128.8 (ArꢀC), 129.6 (ArꢀC), 130.0 (ArꢀC), 131.8 (ArꢀC), 133.5 (ArꢀC), 134.0
(ArꢀC), 135.5 (ArꢀC), 136.7 (ArꢀC), 138.1 (ArꢀC), 139.6 (ꢀN=C), 140.9 (C=N), 141.0 (C=N),
176.9 (C=S); MS m/z (ES–): 515; HRꢀMS(ES–): calcd for C26H23N6O2S2 (MꢀH+), 515.1324;
found, 515.1323.
2-(4-(3,4-Dimethyl-5,5-dioxidobenzo[e]pyrazolo[4,3-c][1,2]thiazin-2(4H)-yl)benzylidene)
-N-(p-tolyl)hydrazinecarbothioamide (3b)
Offꢀwhite powder; m.p.: 200 ºC; FTꢀIR (KBr) cmꢀ1: 3292, 3164, 2985, 2933, 1597, 1516,
1
1472, 1372, 1335, 1258, 1166, 1062, 967, 826, 769; H NMR (DMSOꢀd6, 300 MHz) δ:
2.31(3H, s, CꢀCH3), 2.46 (3H, s, CꢀCH3), 3.04 (3H, s, NꢀCH3), 7.17 (2H, d, J = 8.4 Hz, Arꢀ
H), 7.41 (2H, d, J = 8.4 Hz, ArꢀH), 7.71 (3H, d, J = 8.4 Hz, ArꢀH), 7.83 (1H, t, J=15 Hz, Arꢀ
H), 7.93 (1H, d, J=7.8 Hz, ArꢀH), 8.06 (1H, d, J = 7.8 Hz, ArꢀH), 8.12 (2H, d, J = 8.4 Hz, Arꢀ
H), 8.22 (1H, s, CH), 10.15 (1H, s, NH), 11.88 (1H, s, NH); 13C NMR (DMSOꢀd6, 75 MHz)
δ: 10.3 (CꢀCH3), 20.6 (CꢀCH3), 39.6 (NꢀCH3), 123.8 (ArꢀC), 124.1 (ArꢀC), 124.4 (ArꢀC),
124.6 (2ArꢀC), 125.9 (2ArꢀC), 127.4 (ArꢀC), 128.5 (4ArꢀC), 129.6 (ArꢀC), 131.9 (ArꢀC),
133.5 (ArꢀC), 134.0 (ArꢀC), 134.6 (ArꢀC), 135.7 (ArꢀC), 136.5 (ArꢀC), 138.1 (ꢀN=C), 139.7
(C=N), 141.4 (C=N), 176.2 (C=S); MS m/z (ES–): 515; HRꢀMS (ES–): calcd for
C26H24N6O2S2 (MꢀH+), 515.1324; found, 515.1318.
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2-(4-(3,4-Dimethyl-5,5-dioxidobenzo[e]pyrazolo[4,3-c][1,2]thiazin-2(4H)-yl)benzylidene)
-N-phenylhydrazinecarbothioamide (3c)
Lightꢀbrown powder; m.p.: 184 ºC; FTꢀIR (KBr) cmꢀ1: 3292, 3160, 2985, 2933, 1603, 1517,
1478, 1377, 1335, 1261,1166, 1062, 967, 821, 767; 1H NMR (CDCl3, 400 MHz) δ: 2.45 (3H,
s, CꢀCH3), 3.10 (3H, s, NꢀCH3), 7.27 (1H, d, J= 5.4 Hz, ArꢀH), 7.42 (2H, t, J= 6.0 Hz, ArꢀH),
7.57 (3H, t, J= 6.3 Hz, ArꢀH), 7.67 (3H, t, J= 6.0 Hz, ArꢀH), 7.82 (2H, d, J= 6.3 Hz, ArꢀH),
7.95 (1H, d, J= 5.7 Hz, ArꢀH), 8.00 (1H, s, CH), 8.08 (1H, d, J= 5.7 Hz, ArꢀH), 9.20 (1H, s,
NH), 10.21 (1H, s, NH); 13C NMR (CDCl3, 100 MHz) δ: 10.8 (CꢀCH3), 39.9 (NꢀCH3), 124.1
(ArꢀC), 124.6 (ArꢀC), 124.9 (ArꢀC), 125.0 (2ArꢀC), 126.5 (ArꢀC), 127.9 (ArꢀC), 128.3 (2Arꢀ
C), 128.9 (4ArꢀC), 129.1 (ArꢀC), 132.5 (ArꢀC), 132.8 (ArꢀC), 132.9 (ArꢀC), 133.4 (ArꢀC),
137.7 (ArꢀC), 139.3 (ꢀN=C), 140.8 (C=N), 141.4 (C=NꢀN), 175.9 (C=S); MS m/z (ES–): 501;
HRꢀMS (ES–):calcd for C25H22N6O2S2 (MꢀH+), 501.1167; found, 501.1162.
2-(4-(3,4-Dimethyl-5,5-dioxidobenzo[e]pyrazolo[4,3-c][1,2]thiazin-2(4H)-yl)benzylidene)
-N-(4-ethylphenyl)hydrazinecarbothioamide (3d)
Offꢀwhite powder; m.p.: 195 ºC; FTꢀIR (KBr) cmꢀ1: 3267, 3000, 2918, 2863, 1600, 1489,
1
1374, 1318, 1231, 1163, 1041, 962, 815, 740; H NMR (DMSOꢀd6, 300 MHz) δ: 1.20 (3H, t,
J=7.8 Hz, CꢀCH3), 2.26 (3H, s, CꢀCH3), 2.62 (2H, q, J=7.8 Hz, CꢀCH2), 3.05 (3H, s, NꢀCH3),
7.22 (2H, d, J=8.1 Hz, ArꢀH), 7.45 (2H, d, J=7.8 Hz, ArꢀH), 7.72 (3H, d, J=8.1 Hz, ArꢀH),
7.84 (1H, t, J=7.5 Hz, ArꢀH), 7.95 (1H, d, J=7.5 Hz, ArꢀH), 8.10 (1H, d, J=7.5 Hz, ArꢀH),
8.14 (2H, d, J=8.1 Hz, ArꢀH), 8.24 (1H, s, CH), 10.18 (1H, s, NH), 11.92 (1H, s, NH); 13C
NMR (DMSOꢀd6, 100 MHz) δ: 10.3 (CꢀCH3), 15.7 (CꢀCH3), 27.7 (CꢀCH2), 39.2 (NꢀCH3),
123.1 (ArꢀC), 123.8 (ArꢀC), 124.1 (ArꢀC), 124.4 (ArꢀC), 124.6 (ArꢀC), 125.9 (ArꢀC), 126.5
(ArꢀC), 127.3 (ArꢀC), 127.5 (ArꢀC), 128.4 (ArꢀC), 128.6 (ArꢀC), 129.6 (ArꢀC), 131.8 (ArꢀC),
133.5 (ArꢀC), 134.0 (ArꢀC), 135.5 (ArꢀC), 136.7 (ArꢀC), 137.6 (ArꢀC), 138.10, 139.7 (ꢀN=C),
140.9 (C=N) , 141.4 (C=NꢀN), 176.2 (C=S); MS m/z (ES–): 529.
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2-(4-(3,4-Dimethyl-5,5-dioxidobenzo[e]pyrazolo[4,3-c][1,2]thiazin-2(4H)-yl)benzylidene)
-N-(2,4-dimethylphenyl)hydrazine carbothioamide (3e)
Offꢀwhite powder; m.p.: 303 ºC; FTꢀIR (KBr) cmꢀ1: 3211, 3121, 2980, 1603, 1505, 1436,
1
1360, 1261, 1159, 1064, 967, 842, 743; H NMR (DMSOꢀd6, 300 MHz) δ: 2.20 (3H, s, Cꢀ
CH3), 2.30 (3H, s, CꢀCH3), 2.47 (3H, s, CꢀCH3), 3.05 (3H, s, NꢀCH3), 7.03 (1H, d, J=8.1 Hz,
ArꢀH), 7.12 (1H, d, J=7.2 Hz, ArꢀH), 7.15 (1H, s, ArꢀH), 7.71 (3H, d, J=8.1 Hz, ArꢀH), 7.84
(1H, t, J=7.8 Hz, ArꢀH), 7.94 (1H, d, J=8.1 Hz, ArꢀH), 8.07 (1H, d, J=7.8 Hz, ArꢀH), 8.13
(2H, d, J=8.4 Hz, ArꢀH), 8.22 (1H, s, CH), 10.13 (1H, s, NH), 11.94 (1H, s, NH); 13C NMR
(DMSOꢀd6, 75 MHz) δ: 10.3 (CꢀCH3), 17.7 (CꢀCH3), 20.6 (CꢀCH3), 39.9 (NꢀCH3), 113.1 (Arꢀ
C), 116.9 (ArꢀC), 123.8 (ArꢀC), 124.1 (ArꢀC), 124.5 (ArꢀC), 124.8 (ArꢀC), 126.4 (ArꢀC),
127.4 (ArꢀC), 128.4 (ArꢀC), 128.5 (ArꢀC), 129.6 (ArꢀC), 130.6 (ArꢀC), 131.8 (ArꢀC), 133.5
(ArꢀC), 134.0 (ArꢀC), 134.2 (ArꢀC), 135.2 (ArꢀC), 135.4 (ArꢀC), 135.8 (ArꢀC), 138.1 (ꢀN=C),
139.6 (C=N), 141.1 (C=NꢀN), 177.1 (C=S); MS m/z (ES–): 529; HRꢀMS (ES–): calcd for
C27H25N6O2S2 (MꢀH+), 529.1480; found, 529.1485.
2-(4-(3,4-Dimethyl-5,5-dioxidobenzo[e]pyrazolo[4,3-c][1,2]thiazin-2(4H)-yl)benzylidene)
-N-(2,6-dimethylphenyl)hydrazine carbothioamide (3f)
Offꢀwhite powder; m.p.: 178 ºC; FTꢀIR (KBr) cmꢀ1: 3315, 2966, 2922, 2856, 1603, 1504,
1
1437, 1374, 1233, 1169, 1064, 968, 841,746; HNMR (DMSOꢀd6, 400 MHz) δ: 2.21 (6H, s,
CꢀCH3), 2.47 (3H, s, CꢀCH3), 3.05 (3H, s, NꢀCH3), 7.13 (2H, d, J=8.4 Hz, ArꢀH), 7.71 (4H, t,
J=8.0 Hz, ArꢀH), 7.84 (1H, t, J=8.0 Hz, ArꢀH), 7.95 (1H, d, J=8.0 Hz, ArꢀH), 8.07 (1H, d,
J=8.0 Hz, ArꢀH), 8.14 (2H, d, J=8.0 Hz, ArꢀH), 8.22 (1H, s, CH), 10.02 (1H, s, NH), 11.89
13
(1H, s, NH); C NMR (DMSOꢀd6, 100 MHz) δ: 10.3 (CꢀCH3), 18.0 (CꢀCH3), 20.6 (CꢀCH3),
40.1 (NꢀCH3), 113.1 (ArꢀC), 117.6 (ArꢀC), 123.8 (ArꢀC), 124.1 (ArꢀC), 124.4 (ArꢀC), 124.7
(ArꢀC), 126.9 (ArꢀC), 127.5 (ArꢀC), 128.4 (ArꢀC), 128.6 (ArꢀC), 129.7 (ArꢀC), 130.9 (ArꢀC),
131.8 (ArꢀC), 133.5 (ArꢀC), 134.0 (ArꢀC), 134.1 (ArꢀC), 135.2 (ArꢀC), 135.5 (ArꢀC), 136.4
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(ArꢀC), 138.2 (ꢀN=C) , 139.7 (C=N), 141.0 (C=NꢀN), 177.2 (C=S); MS m/z (ES–): 529; HRꢀ
MS (ES–): calcd for C27H26N6O2S2 (MꢀH+), 529.1480; found, 529.1485.
N-(2-Chlorophenyl)-2-(4-(3,4-dimethyl-5,5-dioxidobenzo[e] pyrazolo[4,3-c][1,2]thiazin-
2(4H)-yl)benzylidene)hydrazine carbothioamide (3g)
Offꢀwhite powder; m.p.: 220 ºC; FTꢀIR (KBr) cmꢀ1: 3271, 2924, 1593, 1507, 1439, 1374,
1
1261, 1169, 1063, 967, 839, 745; HNMR (DMSOꢀd6, 300 MHz) δ: 2.46 (3H, s, CꢀCH3),
3.05 (3H, s, NꢀCH3), 7.31ꢀ7.43 (4H, m, ArꢀH), 7.57 (1H, d, J=7.8 Hz, ArꢀH), 7.69 (2H, dd,
J1=8.4 Hz, J2=19.8 Hz, ArꢀH), 7.84 (1H, t, J=7.8 Hz, ArꢀH), 7.95 (2H, d, J=7.8 Hz, ArꢀH),
8.10 (2H, dd, J1=8.4 Hz, J2=13.5 Hz, ArꢀH), 8.25 (1H, s, CH), 10.22 (1H, s, NH), 12.12 (1H,
13
s, NH); C NMR (DMSOꢀd6, 75 MHz) δ: 10.3 (CꢀCH3), 39.7 (NꢀCH3), 115.1 (ArꢀC), 115.8
(ArꢀC), 123.8 (ArꢀC), 124.1 (ArꢀC), 124.4 (ArꢀC), 124.7 (ArꢀC), 127.1 (ArꢀC), 127.3 (ArꢀC),
127.9 (ArꢀC), 128.4 (ArꢀC), 129.3 (ArꢀC), 129.6 (ArꢀC), 130.1 (ArꢀC), 130.9 (ArꢀC), 131.8
(ArꢀC), 133.5 (ArꢀC), 133.9 (ArꢀC), 134.0 (ArꢀC), 136.6 (ArꢀC), 138.1(ꢀN=C), 139.8 (C=N),
141.6 (C=NꢀN), 176.9 (C=S); MS m/z (ES–): 535; HRꢀMS (ES–): calcd for C25H20ClN6O2S2
(MꢀH+), 535.0778; found, 535.0780.
N-(3-Chlorophenyl)-2-(4-(3,4-dimethyl-5,5-dioxidobenzo[e]pyrazolo[4,3-c][1,2]thiazin-
2(4H)-yl)benzylidene)hydrazine carbothioamide (3h)
Creamy white powder; m.p.: 221 ºC; FTꢀIR (KBr) cmꢀ1: 3304, 2979, 2924, 1596, 1509, 1436,
1
1374, 1252, 1169, 1064, 966, 841, 745; H NMR (DMSOꢀd6, 400 MHz): δ: 2.48 (3H, s, Cꢀ
CH3), 3.05 (3H, s, NꢀCH3), 7.37 (1H, d, J=7.8 Hz, ArꢀH), 7.49 (1H, t, J=7.8 Hz, ArꢀH), 7.68
(2H, d, J=7.8 Hz, ArꢀH), 7.70ꢀ785 (2H, m, ArꢀH), 7.90 (2H, t, J=7.8 Hz, ArꢀH), 8.05 (2H, d,
J=7.8Hz, ArꢀH), 8.12 (2H, d, J=7.8Hz, ArꢀH), 8.19 (2H, d, J=7.8Hz, ArꢀH), 8.32 (1H, s,
CH), 10.42 (1H, s, NH), 12.12 (1H, s, NH); 13C NMR (DMSOꢀd6, 100 MHz) δ: 10.3 (Cꢀ
CH3), 39.7 (NꢀCH3), 115.2 (ArꢀC), 115.9 (ArꢀC), 124.1 (ArꢀC), 124.3 (ArꢀC), 124.4 (ArꢀC),
124.6 (ArꢀC), 125.3 (ArꢀC), 127.3 (ArꢀC), 128.6 (ArꢀC), 129.5 (ArꢀC), 129.7 (ArꢀC), 130.1
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(ArꢀC), 130.9 (ArꢀC), 131.8 (ArꢀC), 132.1 (ArꢀC), 133.5 (ArꢀC), 133.8 (ArꢀC), 134.0 (ArꢀC),
136.6 (ArꢀC), 138.1(ꢀN=C), 139.8 (C=N), 140.5 (C=NꢀN), 176.9 (C=S); MS m/z (ES–): 535;
HRꢀMS (ES–): calcd for C25H20ClN6O2S2 (MꢀH+), 535.0778; found, 535.0777.
N-(4-Chlorophenyl)-2-(4-(3,4-dimethyl-5,5-dioxidobenzo[e]pyrazolo[4,3-c][1,2]thiazin-
2(4H)-yl)benzylidene)hydrazine carbothioamide (3i)
Lightꢀyellow crystalline solid; m.p.: 225 ºC; FTꢀIR (KBr) cmꢀ1: 3280, 3129, 2974, 2926,
1589, 1506, 1437, 1371, 1258, 1157, 1064, 965, 827, 744; 1H NMR (DMSOꢀd6, 400 MHz) δ:
2.26 (3H, s, CꢀCH3), 3.05 (3H, s, NꢀCH3), 7.45 (2H, d, J=8.4 Hz, ArꢀH), 7.62 (2H, d, J=8.8
Hz, ArꢀH), 7.73 (3H, t, J=7.6 Hz, ArꢀH), 7.85 (1H, t, J=7.6 Hz, ArꢀH), 7.95 (1H, d, J=7.6 Hz,
ArꢀH), 8.07 (1H, d, J=8.0 Hz, ArꢀH), 8.15 (2H, d, J=8.4 Hz, ArꢀH), 8.26 (1H, s, CH), 10.22
(1H, s, NH), 12.12 (1H, s, NH); 13C NMR (DMSOꢀd6, 100 MHz) δ: 10.3 (CꢀCH3), 39.6 (Nꢀ
CH3), 115.2 (ArꢀC), 115.8 (ArꢀC), 123.8 (ArꢀC), 124.3 (ArꢀC), 124.4 (ArꢀC), 124.6 (ArꢀC),
125.3 (ArꢀC), 127.6 (ArꢀC), 128.5 (ArꢀC), 129.6 (ArꢀC), 129.6 (ArꢀC), 130.0 (ArꢀC), 130.9
(ArꢀC), 131.8 (ArꢀC), 132.1 (ArꢀC), 133.5 (ArꢀC), 133.8 (ArꢀC), 134.0 (ArꢀC), 136.5 (ArꢀC),
138.1 (N=C), 139.8 (C=N), 141.8 (C=NꢀN), 176.9 (C=S); MS m/z (ES–):535; HRꢀMS (ES–):
calcd for C25H20ClN6O2S2 (MꢀH+), 535.0778; found, 535.0783.
2-(4-(3,4-Dimethyl-5,5-dioxidobenzo[e]pyrazolo[4,3-c][1,2]thiazin-2(4H)-yl)benzylidene)
-N-(2-fluorophenyl)hydrazinecarbothioamide (3j)
Light yellow powder; m.p.: 308 ºC; FTꢀIR (KBr) cmꢀ1: 3325, 3102, 2958, 1598, 1508, 1433,
1374, 1344, 1272, 1163, 1065, 968, 846, 745; 1H NMR (DMSOꢀd6, 300 MHz) δ: 3.05 (3H, s,
CꢀCH3), 3.34 (3H, s, NꢀCH3), 7.21ꢀ7.34 (4H, m, ArꢀH), 7.51 (1H, t, J=7.5 Hz, ArꢀH), 7.73
(3H, d, J=8.7 Hz, ArꢀH), 7.84 (1H, t, J=7.8 Hz, ArꢀH), 7.95 (1H, d, J=8.8 Hz, ArꢀH), 8.10
(2H, dd, J1=7.8 Hz, J2=16.2 Hz, ArꢀH), 8.25 (1H, s, CH), 10.11 (1H, s, NH), 12.10 (1H, s,
NH); 13C NMR (DMSOꢀd6, 75 MHz) δ: 10.3 (CꢀCH3), 38.7 (NꢀCH3), 115.6 (ArꢀC), 115.8
(ArꢀC), 123.8 (ArꢀC), 123.9 (ArꢀC), 124.1 (ArꢀC), 124.4 (ArꢀC), 124.7 (ArꢀC), 127.0 (ArꢀC),
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127.2 (ArꢀC), 127.3 (ArꢀC), 128.2 (ArꢀC), 128.3 (ArꢀC), 128.5 (ArꢀC), 129.6 (ArꢀC), 130.3
(ArꢀC), 131.9 (ArꢀC), 133.5 (ArꢀC), 133.9 (ArꢀC), 134.0 (ArꢀC), 138.1 (ꢀN=C), 139.8 (C=N),
141.7 (C=NꢀN), 177.5 (C=S); MS m/z (ES–): 519; HRꢀMS (ES–): calcd for C25H20FN6O2S2
(MꢀH+), 519.1073; found, 519.1078.
2-(4-(3,4-Dimethyl-5,5-dioxidobenzo[e]pyrazolo[4,3-c][1,2]thiazin-2(4H)-yl)benzylidene)
-N-(3-fluorophenyl)hydrazinecarbothioamide (3k)
Light yellow powder; m.p.: 312 ºC; FTꢀIR (KBr) cmꢀ1: 3340, 2966, 1595, 1513, 1433, 1374,
1
1345, 1271, 1167, 1069, 967, 843, 744; H NMR (DMSOꢀd6, 300 MHz) δ: 2.47 (3H, s, Cꢀ
CH3), 3.05 (3H, s, NꢀCH3), 7.06 (1H, t, J=7.8 Hz, ArꢀH), 7.38ꢀ7.48 (2H, m, ArꢀH), 7.64 (1H,
t, J=11.1 Hz, ArꢀH), 7.73 (3H, t, J=7.8 Hz, ArꢀH), 7.84 (1H, t, J=7.8 Hz, ArꢀH), 7.92 (1H, d,
J=7.8 Hz, ArꢀH), 8.11 (3H, dd, J1=8.4 Hz, J2=16.8 Hz, ArꢀH), 8.27 (1H, s, CH), 10.31 (1H, s,
NH), 12.11 (1H, s, NH); 13C NMR (DMSOꢀd6, 75 MHz) δ: 10.3 (CꢀCH3), 38.7 (NꢀCH3),
111.7 (ArꢀC), 112.0 (ArꢀC), 112.2 (ArꢀC), 112.5 (ArꢀC), 121.4 (ArꢀC), 123.8 (ArꢀC), 124.4
(ArꢀC), 124.6 (ArꢀC), 127.4 (ArꢀC), 128.3 (ArꢀC), 128.6 (ArꢀC), 129.4 (ArꢀC), 129.5 (ArꢀC),
129.6 (ArꢀC), 131.8 (ArꢀC), 133.4 (ArꢀC), 133.7 (ArꢀC), 133.9 (ArꢀC), 134.0 (ArꢀC), 138.1
(ꢀN=C), 139.8 (C=N), 142.0 (C=NꢀN), 175.9 (C=S); MS m/z (ES–): 519; HRꢀMS(ES–): calcd
for C25H20FN6O2S2 (MꢀH+), 519.1073; found, 519.1072.
2-(4-(3,4-Dimethyl-5,5-dioxidobenzo[e]pyrazolo[4,3-c][1,2]thiazin-2(4H)-yl)benzylidene)
-N-(4-fluorophenyl)hydrazinecarbothioamide (3l)
Light yellow powder; m.p.: 310 ºC; FTꢀIR (KBr) cmꢀ1: 3338, 3126, 2997, 2963, 1601, 1507,
1
1435, 1374, 1345, 1267, 1156, 1066, 964, 830,740; H NMR (DMSOꢀd6, 400 MHz) δ: 2.47
(3H, s, CꢀCH3), 3.06 (3H, s, NꢀCH3), 7.23 (2H, t, J=8.8 Hz, ArꢀH), 7.55 (3H, dd, J1=4.8 Hz,
J2=8.8 Hz, ArꢀH), 7.72 (2H, dd, J1=4.0 Hz, J2=8.4 Hz, ArꢀH), 7.85 (1H, t, J=8.4 Hz, ArꢀH),
7.95 (1H, d, J= 8.0 Hz, ArꢀH), 8.11 (3H, dd, J1=8.4 Hz, J2=16.4 Hz, ArꢀH), 8.25 (1H, s, CH),
10.26 (1H, s, NH), 12.00 (1H, s, NH); 13C NMR (DMSOꢀd6, 100 MHz) δ: 10.3 (CꢀCH3), 38.8
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(NꢀCH3), 114.6 (ArꢀC), 114.8 (ArꢀC), 123.8 (ArꢀC), 123.9 (ArꢀC), 124.1 (ArꢀC), 124.4 (Arꢀ
C), 124.6 (ArꢀC), 127.0 (ArꢀC), 127.2 (ArꢀC), 127.4, 128.2 (ArꢀC), 128.3 (ArꢀC), 128.5 (Arꢀ
C), 129.6 (ArꢀC), 130.3 (ArꢀC), 131.8 (ArꢀC), 133.5 (ArꢀC), 133.9 (ArꢀC), 134.0 (ArꢀC),
138.1(ꢀN=C), 139.7(C=N), 141.6 (C=NꢀN), 176.5 (C=S); MS m/z (ES–): 519; HRꢀMS (ES–):
calcd for C25H20FN6O2S2 (MꢀH+), 519.1073; found, 519.1083.
N-Benzyl-2-(4-(3,4-dimethyl-5,5-dioxidobenzo[e]pyrazolo[4,3-c][1,2]thiazin-2(4H)-
yl)benzylidene)hydrazinecarbothioamide (3m)
Offꢀwhite powder; m.p.: 247 ºC; FTꢀIR (KBr) cmꢀ1: 3322, 3150, 3059, 2971, 2938, 1601,
1
1541, 1504, 1438, 1374, 1331, 1259, 1165, 1064, 963, 841,743; H NMR (DMSOꢀd6, 400
MHz) δ: 2.50 (3H, s, CꢀCH3), 3.05 (3H, s, NꢀCH3), 4.87 (2H, d, J= 6.0 Hz, NꢀCH2), 7.25 (2H,
t, J= 7.2 Hz, ArꢀH), 7.35 (3H, q, J= 8.0 Hz, ArꢀH), 7.71 (2H, dd, J1=4.0 Hz, J2= 8.4 Hz, Arꢀ
H), 7.84 (1H, t, J=6.4 Hz, ArꢀH), 7.95 (1H, d, J=8.0 Hz, ArꢀH), 8.05 (3H, dd, J1=3.6 Hz, J2=
8.8 Hz, ArꢀH), 8.18 (1H, s, CH), 9.25 (1H, t, J=6.4 Hz, NH), 11.76 (1H, s, NH); 13C NMR
(DMSOꢀd6, 100 MHz) δ: 10.3 (CꢀCH3), 38.8 (NꢀCH3), 46.6 (CꢀCH2), 123.8 (ArꢀC), 123.9
(ArꢀC), 124.0 (ArꢀC), 124.4 (ArꢀC), 124.7 (ArꢀC), 126.7 (ArꢀC), 127.1 (ArꢀC), 127.3 (ArꢀC),
128.1 (ArꢀC), 128.5 (ArꢀC), 129.6 (ArꢀC), 130.3 (ArꢀC), 131.8 (ArꢀC), 132.5 (ArꢀC), 133.5
(ArꢀC), 133.9 (ArꢀC), 134.0 (ArꢀC), 134.1 (ArꢀC), 138.0 (ArꢀC), 139.4 (ꢀN=C), 139.6
(C=N), 141.0 (C=NꢀN), 177.6 (C=S); MS m/z (ES–): 515; HRꢀMS (ES–): calcd for
C26H23N6O2S2 (MꢀH+), 515.1324; found, 515.1325.
2-(4-(3,4-Dimethyl-5,5-dioxidobenzo[e]pyrazolo[4,3-c][1,2]thiazin-2-(4H)-yl)benzyl-
idene)-N-(morpholinomethyl)hydrazinecarbothioamide (3n)
Offꢀwhite powder; m.p.: 250 ºC; FTꢀIR (KBr) cmꢀ1: 3325, 3130, 2987, 2936, 1610, 1561,
1501, 1438, 1376, 1336, 1259, 1165, 1064, 965, 844, 744; 1H NMR (DMSOꢀd6, 400 MHz) δ:
2.45 (4H, t, J=2.4 Hz, CꢀCH2), 3.05 (3H, s, CꢀCH3), 3.35 (3H, s, NꢀCH3), 3.58 (4H, t, J=4.8
Hz, OꢀCH2), 4.89 (2H, d, J=5.2 Hz, NꢀCH2), 7.43 (2H, dd, J1=4.4 Hz, J2=8.4 Hz, ArꢀH), 7.50
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(2H, dd, J1=4.0 Hz, J2=8.4 Hz, ArꢀH), 7.72 (2H, dd, J1=4.4 Hz, J2=8.4 Hz, ArꢀH), 7.84 (1H,
dt, J1=1.2 Hz, J2=7.6 Hz, J3=16.0 Hz, ArꢀH), 8.05 (1H, dd, J1=3.6 Hz, J2=8.8 Hz, ArꢀH),
8.19 (1H, s, CH), 9.45 (1H, t, J=6.0 Hz, NH), 11.89 (1H, s, NH); 13C NMR (DMSOꢀd6, 100
MHz) δ: 10.2 (CꢀCH3), 38.8 (NꢀCH3), 57.4 (2C, NꢀCH2), 69.9 (2C, OꢀCH2), 81.2 (NꢀCH2ꢀN),
123.9 (ArꢀC), 124.0 (ArꢀC), 124.4 (ArꢀC), 127.4 (ArꢀC), 128.5 (ArꢀC), 129.7 (ArꢀC), 130.8
(ArꢀC), 132.6 (ArꢀC), 133.5 (ArꢀC), 134.1 (ArꢀC), 138.0 (ArꢀC), 139.4 (ArꢀC), 139.7 (ꢀN=C),
140.8 (C=N), 143.1 (C=NꢀN), 177.7 (C=S); MS m/z (ES–): 524.
2-(4-(3,4-Dimethyl-5,5-dioxidobenzo[e]pyrazolo[4,3-c][1,2]thiazin-2(4H)-yl)benzylidene)
hydrazinecarbothioamide (3o)
Light yellow powder; m.p.: 271 ºC; FTꢀIR (KBr) cmꢀ1: 3463, 3343, 3253, 2986, 2949, 1585,
1499, 1431, 1371, 1333, 1261, 1157, 1061, 962, 842,768; 1H NMR (DMSOꢀd6, 300 MHz) δ:
2.46 (3H, s, CꢀCH3), 3.05 (3H, s, NꢀCH3), 7.70 (3H, d, J=8.8 Hz, ArꢀH), 7.84 (1H, t, J=7.5
Hz, ArꢀH), 7.95 (1H, d, J=7.8 Hz, ArꢀH), 8.08 (3H, t, J=9.0 Hz, ArꢀH), 8.14 (2H, s, NH2),
8.29 (1H, s, CH), 11.56 (1H, s, NH); 13C NMR (DMSOꢀd6, 75 MHz) δ: 10.3 (CꢀCH3), 38.7
(NꢀCH3), 123.8 (ArꢀC), 124.1 (ArꢀC), 124.4 (ArꢀC), 124.7 (ArꢀC), 127.4 (ArꢀC), 128.2 (Arꢀ
C), 128.8 (ArꢀC), 129.6 (ArꢀC), 130.8 (ArꢀC), 131.8 (ArꢀC), 133.4 (ArꢀC), 133.9 (ArꢀC),
134.1 (ArꢀC), 138.0 (ꢀN=C), 139.6 (C=N), 140.9 (C=NꢀN), 178.2 (C=S); MS m/z (ES–):
425; HRꢀMS(ES–): calcd for C19H17N6 O2S2 (MꢀH+), 425.0854; found, 425.0851.
2-(4-(4-Methyl-5,5-dioxido-3-phenylbenzo[e]pyrazolo[4,3-c][1,2]thiazin-2(4H)-
yl)benzylidene)-N-(o-tolyl)hydrazinecarbothioamide (4a)
Offꢀwhite powder; m.p.: 206 ºC; FTꢀIR (KBr cmꢀ1: 3349, 3211, 3063, 1604, 1511, 1461,
1
1348, 1265, 1182, 1061, 970, 838, 771; H NMR (DMSOꢀd6, 400 MHz) δ: 2.31 (3H, s, Cꢀ
CH3), 2.90 (3H, s, NꢀCH3), 7.14 (2H, dd, J1=2.4 Hz, J2=6.4 Hz, ArꢀH), 7.21ꢀ7.31 (2H, m, Arꢀ
H), 7.49 (1H, t, J=7.2 Hz, ArꢀH), 7.59 (2H, t, J=8.0 Hz, ArꢀH), 7.65 (2H, d, J=8.8 Hz, ArꢀH),
7.73 (3H, m, ArꢀH), 8.04 (3H, t, J=7.2 Hz, ArꢀH), 8.17 (2H, d, J=8.8 Hz, ArꢀH), 8.26 (1H, s,
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CH), 10.15 (1H, s, NH), 11.96 (1H, s, NH); 13C NMR (DMSOꢀd6, 100 MHz) δ: 17.8 (Cꢀ
CH3), 39.7 (NꢀCH3), 123.8 (ArꢀC), 123.9 (ArꢀC), 124.2 (ArꢀC), 124.4 (ArꢀC), 124.6 (ArꢀC),
125.3 (ArꢀC), 125.9 (ArꢀC), 126.0 (ArꢀC), 126.8 (ArꢀC), 127.3 (ArꢀC), 128.2 (ArꢀC), 128.3
(ArꢀC), 128.5 (ArꢀC), 128.8 (ArꢀC), 129.0 (ArꢀC), 129.2 (ArꢀC), 129.7 (ArꢀC), 130.0 (ArꢀC),
130.0 (ArꢀC), 130.3 (ArꢀC), 131.8 (ArꢀC), 133.1 (ArꢀC), 133.5 (ArꢀC), 133.9 (ArꢀC), 134.1
(ArꢀC), 138.0 (ꢀN=C), 139.7 (C=N), 140.9 (C=NꢀN), 177.0 (C=S); MS m/z (ES–): 577; HRꢀ
MS (ES–): calcd for C31H25N6 O2S2 (MꢀH+), 577.1480; found, 577.1483.
2-(4-(4-Methyl-5,5-dioxido-3-phenylbenzo[e]pyrazolo[4,3-c][1,2]thiazin-2(4H)-
yl)benzylidene)-N-(p-tolyl)hydrazinecarbothioamide (4b)
Offꢀwhite powder; m.p.: 205 ºC; FTꢀIR (KBr) cmꢀ1: 3315, 3065, 2921 1622, 1501, 1463,
1
1347, 1261, 1182, 1057, 968, 835, 767; H NMR (DMSOꢀd6, 400 MHz) δ: 2.29 (3H, s, Cꢀ
CH3), 2.90 (3H, s, NꢀCH3), 7.13ꢀ7.20 (2H, dd, J1=8.4 Hz, J2=20.4 Hz, ArꢀH), 7.42 (2H, d,
J=8.4 Hz, ArꢀH), 7.49 (2H, t, J=7.6 Hz, ArꢀH), 7.59 (2H, t, J=7.6 Hz, ArꢀH), 7.66 (2H, d,
J=8.8 Hz, ArꢀH), 7.72 (4H, 2×dd, J1=7.6 Hz, J2=14.0 Hz, ArꢀH), 8.05 (2H, dd, J1=2.4 Hz,
J2=7.2 Hz, ArꢀH), 8.17 (1H, d, J=8.4Hz, ArꢀH), 8.26 (1H, s, CH), 10.20 (1H, s, NH), 11.94
13
(1H, s, NH); C NMR (DMSOꢀd6, 100 MHz) δ: 20.6 (CꢀCH3), 38.5 (NꢀCH3), 123.8 (ArꢀC),
123.9 (ArꢀC), 124.3 (ArꢀC), 124.4(ArꢀC), 124.6 (ArꢀC), 125.2 (ArꢀC), 125.9 (ArꢀC), 126.0
(ArꢀC), 126.5 (ArꢀC), 127.2 (ArꢀC), 128.2 (ArꢀC), 128.3 (ArꢀC), 128.5 (ArꢀC), 128.9 (ArꢀC),
129.0 (ArꢀC), 129.2 (ArꢀC), 129.7 (ArꢀC), 130.0 (ArꢀC), 130.1 (ArꢀC), 130.5 (ArꢀC), 131.8
(ArꢀC), 133.1 (ArꢀC), 133.5 (ArꢀC), 133.9 (ArꢀC), 134.0 (ArꢀC), 138.0 (ꢀN=C), 139.7
(C=N), 140.9 (C=NꢀN), 176.2 (C=S); MS m/z (ES–): 577; HRꢀMS (ES–): calcd for C31H25N6
O2S2 (MꢀH+), 577.1480; found, 577.1485.
2-(4-(4-Methyl-5,5-dioxido-3-phenylbenzo[e]pyrazolo[4,3-c][1,2]thiazin-2(4H)-
yl)benzylidene)-N-phenylhydrazinecarbothioamide (4c)
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Offꢀwhite powder; m.p.: 191 ºC; FTꢀIR (KBr) cmꢀ1: 3310, 3058, 2922 1602, 1508, 1463,
1
1347, 1263, 1181, 1059, 968, 835, 769; H NMR (DMSOꢀd6, 400 MHz) δ: 2.90 (3H, s, Nꢀ
CH3), 7.14 (2H, dd, J1=2.8 Hz, J2=7.2 Hz, ArꢀH), 7.24ꢀ7.26 (2H, m, ArꢀH), 7.33 (2H, t, J=7.2
Hz, ArꢀH), 7.47 (1H, t, J=7.6 Hz, ArꢀH), 7.57 (2H, t, J=8.0 Hz, ArꢀH), 7.65 (2H, d, J=8.8 Hz,
ArꢀH), 7.69ꢀ7.76 (3H, m , ArꢀH), 8.04 (2H, t, J=7.6 Hz, ArꢀH), 8.17 (2H, d, J=8.8 Hz, Arꢀ
H), 8.24 (1H, s, CH), 10.15 (1H, s, NH), 11.95 (1H, s, NH); 13C NMR (DMSOꢀd6, 100 MHz)
δ: 38.5 (NꢀCH3), 123.5 (ArꢀC), 123.9 (ArꢀC), 124.3 (ArꢀC), 124.4 (ArꢀC), 124.6 (ArꢀC),
125.2 (ArꢀC), 125.9 (ArꢀC), 126.0 (ArꢀC), 126.3 (ArꢀC), 127.2 (ArꢀC), 128.2 (ArꢀC), 128.2
(ArꢀC), 128.5 (ArꢀC), 128.9 (ArꢀC), 129.0 (ArꢀC), 129.1 (ArꢀC), 129.7 (ArꢀC), 129.9 (ArꢀC),
130.3 (ArꢀC), 130.5 (ArꢀC), 131.5 (ArꢀC), 133.1 (ArꢀC), 133.5 (ArꢀC), 133.9 (ArꢀC), 134.0
(ArꢀC), 137.9 (ꢀN=C), 139.7 (C=N), 140.9 (C=NꢀN), 176.0 (C=S); MS m/z (ES–): 563; HRꢀ
MS (ES–): calcd for C30H23N6 O2S2 (MꢀH+), 563.1324; found, 563.1326.
N-(4-Ethylphenyl)-2-(4-(4-methyl-5,5-dioxido-3-phenylbenzo[e]pyrazolo[4,3-c][1,2]
thiazin-2(4H)-yl)benzylidene)hydrazine carbothioamide (4d)
Offꢀwhite powder; m.p.: 215 ºC; FTꢀIR (KBr) cmꢀ1: 3310, 2958, 2922, 2853, 1597, 1517,
1
1462, 1346, 1260, 1180, 1061, 968, 835, 771; H NMR (DMSOꢀd6, 400 MHz) δ: 1.20 (3H, t,
J=8.4 Hz, CꢀCH3), 2.60 (2H, q, J= 8.0 Hz, CꢀCH2), 2.90 (3H, s, NꢀCH3), 7.14 (1H, d, J=8.8
Hz, ArꢀH), 7.21 (2H, t, J=8.4 Hz, ArꢀH), 7.41ꢀ7.77 (4H, m, ArꢀH), 7.59 (2H, t, J=7.6 Hz, Arꢀ
H), 7.66 (1H, d, J=8.8 Hz, ArꢀH), 7.70ꢀ7.77 (3H, m, ArꢀH), 7.90 (1H, t, J=8.0 Hz, ArꢀH),
8.02 (2H, d, J=7.2 Hz, ArꢀH), 8.17 (1H, d, J=9.6 Hz, ArꢀH), 8.27 (1H, s, CH), 10.20 (1H, s,
NH), 11.95 (1H, s, NH); 13C NMR (DMSOꢀd6, 100 MHz) δ: 15.7 (CꢀCH3), 27.7 (CꢀCH2),
39.7 (NꢀCH3), 123.8 (ArꢀC), 123.9 (ArꢀC), 124.4 (ArꢀC), 124.6 (ArꢀC), 125.9 (ArꢀC), 126.3
(ArꢀC), 127.3 (ArꢀC), 128.2 (ArꢀC), 128.3 (ArꢀC), 128.5 (ArꢀC), 129.3 (ArꢀC), 129.6 (ArꢀC),
129.9 (ArꢀC), 130.0 (ArꢀC), 130.5 (ArꢀC), 131.7 (ArꢀC), 133.1 (ArꢀC), 133.5 (ArꢀC), 133.9
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(ArꢀC), 138.0 (ꢀN=C), 139.6 (C=N), 141.0 (C=NꢀN), 176.2 (C=S); MS m/z (ES–): 591; HRꢀ
MS (ES–): calcd for C27H25N6O2S2 (MꢀH+), 591.1637; found, 591.1639.
N-(2,4-Dimethylphenyl)-2-(4-(4-methyl-5,5-dioxido-3-phenylbenzo[e]pyrazolo[4,3-
c][1,2]thiazin-2(4H)-yl)benzylidene)hydrazine carbothioamide (4e)
Offꢀwhite powder; m.p.: 249 ºC; FTꢀIR (KBr) cmꢀ1: 3310, 3058, 2922, 1602, 1508, 1463,
1
1347, 1263, 1181, 1059, 968, 835, 769; H NMR (DMSOꢀd6, 300 MHz) δ: 2.20 (3H, s, Cꢀ
CH3), 2.30 (3H, s, CꢀCH3), 2.90 (3H, s, NꢀCH3), 7.05 (2H, d, J=7.8 Hz, ArꢀH), 7.11 (1H, dd,
J1=6.3 Hz, J2=10.8 Hz, ArꢀH), 7.50 (1H, d, J=6.6 Hz, ArꢀH), 7.57 (2H, d, J=7.5 Hz, ArꢀH),
7.63 (1H, t, J=8.1 Hz, ArꢀH), 7.72 (2H, t, J=7.5 Hz, ArꢀH), 8.05 (4H, dd, J1=2.8 Hz, J2=9.2
Hz, ArꢀH), 8.17 (3H, d, J=9.8 Hz, ArꢀH), 8.24 (1H, s, CH), 10.06 (1H, s, NH), 11.91 (1H, s,
NH); 13C NMR (DMSOꢀd6, 75 MHz) δ: 17.7 (CꢀCH3), 20.6 (CꢀCH3), 38.5 (NꢀCH3), 123.6
(ArꢀC), 123.9 (ArꢀC), 124.3 (ArꢀC), 124.4 (ArꢀC), 124.6 (ArꢀC), 125.3 (ArꢀC), 125.9 (ArꢀC),
126.0 (ArꢀC), 126.1 (ArꢀC), 126.4 (ArꢀC), 127.3 (ArꢀC), 128.2 (ArꢀC), 128.3 (ArꢀC), 128.5
(ArꢀC), 128.8 (ArꢀC), 129.2 (ArꢀC), 129.7 (ArꢀC), 130.3 (ArꢀC), 130.6 (ArꢀC), 131.8 (ArꢀC),
133.1 (ArꢀC), 133.5 (ArꢀC), 133.9 (ArꢀC), 135.2 (ArꢀC), 135.4 (ArꢀC), 138.9 (ꢀN=C), 139.7
(C=N), 140.9 (C=NꢀN), 177.2 (C=S); MS m/z (ES–): 591; HRꢀMS (ES–): calcd for C32H27N6
O2S2 (MꢀH+), 591.1637; found, 591.1614.
N-(2,6-Dimethylphenyl)-2-(4-(4-methyl-5,5-dioxido-3-phenylbenzo[e]pyrazolo[4,3-
c][1,2]thiazin-2(4H)-yl)benzylidene)hydrazine carbothioamide (4f)
Light yellow powder; m.p.: 256 ºC; FTꢀIR (KBr) cmꢀ1: 3248, 3128, 2978, 2913, 2853, 1601,
1
1503, 1452, 1356, 1260, 1157, 1059, 968, 841, 779; H NMR (DMSOꢀd6, 300 MHz) δ: 2.21
(6H, s, CꢀCH3), 2.91 (3H, s, NꢀCH3), 7.02 (2H, d, J=8.1 Hz, ArꢀH), 7.07ꢀ7.16 (3H, m, ArꢀH),
7.49 (1H, t, J=6.6 Hz, ArꢀH), 7.56 (2H, d, J=7.8 Hz, ArꢀH), 7.61 (1H, t, J=8.4 Hz, ArꢀH),
7.72 (1H, d, J=7.5 Hz, ArꢀH), 8.07 (4H, dd, J1=2.8 Hz, J2=9.8 Hz, ArꢀH), 8.17 (2H, d, J=9.2
Hz, ArꢀH), 8.25 (1H, s, CH), 10.07 (1H, s, NH), 11.96 (1H, s, NH); 13C NMR (DMSOꢀd6, 75
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MHz) δ: 17.7 (CꢀCH3), 20.7 (CꢀCH3), 38.6 (NꢀCH3), 123.5(ArꢀC), 123.5 (ArꢀC), 124.3 (Arꢀ
C), 124.4 (ArꢀC), 124.6 (ArꢀC), 125.3 (ArꢀC), 125.9 (ArꢀC), 126.0 (ArꢀC), 126.2 (ArꢀC),
126.3 (ArꢀC), 127.3 (ArꢀC), 128.3 (ArꢀC), 128.6 (ArꢀC), 128.9 (ArꢀC), 129.2 (ArꢀC), 129.7
(ArꢀC), 130.0 (ArꢀC), 130.5 (ArꢀC), 130.7 (ArꢀC), 131.8 (ArꢀC), 133.1 (ArꢀC), 133.6 (ArꢀC),
133.9 (ArꢀC), 135.2 (ArꢀC), 135.4 (ArꢀC), 138.9(ꢀN=C) , 139.8 (C=N), 140.8 (C=NꢀN),
177.1 (C=S); MS m/z (ES–): 591; HRꢀMS (ES–): calcd for C32H27N6O2S2 (MꢀH+), 591.1637;
found, 591.1634.
N-(2-Chlorophenyl)-2-(4-(4-methyl-5,5-dioxido-3-phenylbenzo[e]pyrazolo[4,3-c][1,2]
thiazin-2(4H)-yl)benzylidene)hydrazine carbothioamide (4g)
Offꢀwhite powder; m.p.: 225 ºC; FTꢀIR (KBr) cmꢀ1: 3318, 3157, 1612, 1508, 1464, 1347,
1
1261, 1182, 1059, 969, 835, 767; H NMR (DMSOꢀd6, 400 MHz) δ: 2.91 (3H, s, NꢀCH3),
7.15 (1H, d, J=7.2 Hz, ArꢀH), 7.34 (1H, t, J=7.6 Hz, ArꢀH), 7.40 (1H, t, J=7.6 Hz, ArꢀH),
7.50 (2H, d, J=7.2 Hz, ArꢀH), 7.59 (2H, t, J=12.0 Hz, ArꢀH), 7.68 (3H, t, J=7.2 Hz, ArꢀH),
8.05 (4H, dd, J1=2.8 Hz, J2=7.2 Hz, ArꢀH), 8.15 (3H, d, J=8.0 Hz, ArꢀH), 8.28 (1H, s, CH),
10.25 (1H, s, NH), 12.15 (1H, s, NH); 13C NMR (DMSOꢀd6, 100 MHz) δ: 38.8 (NꢀCH3),
115.5 (ArꢀC), 115.7 (ArꢀC), 123.5 (ArꢀC), 123.9 (ArꢀC), 124.3 (ArꢀC), 124.6 (ArꢀC), 125.3
(ArꢀC), 125.9 (ArꢀC), 126.1 (ArꢀC), 127.1 (ArꢀC), 128.1 (ArꢀC), 128.2 (ArꢀC), 128.8 (ArꢀC),
129.1 (ArꢀC), 129.3 (ArꢀC), 129.7 (ArꢀC), 130.0 (ArꢀC), 130.5 (ArꢀC), 131.8 (ArꢀC), 133.1
(ArꢀC), 133.5 (ArꢀC), 133.9 (ArꢀC), 134.6 (ArꢀC), 139.6 (ArꢀC), 139.9 (ArꢀC), 140.0 (ꢀ
N=C), 140.9 (C=N), 143.7 (C=NꢀN), 176.6 (C=S); MS m/z (ES–): 597; HRꢀMS (ES–): calcd
for C30H22ClN6 O2S2 (MꢀH+), 597.0934; found, 597.0935.
N-(3-Chlorophenyl)-2-(4-(4-methyl-5,5-dioxido-3-phenylbenzo[e]pyrazolo[4,3-c][1,2]
thiazin-2(4H)-yl)benzylidene)hydrazine carbothioamide (4h)
Offꢀwhite powder; m.p.: 208 ºC; FTꢀIR (KBr) cmꢀ1: 3310, 3158, 1606, 1548, 1461, 1346,
1
1265, 1182, 1059, 963, 832, 767; H NMR (DMSOꢀd6, 300 MHz) δ: 2.90 (3H, s, NꢀCH3),
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7.16 (1H, d, J=7.2 Hz, ArꢀH), 7.36 (1H, t, J=7.2 Hz, ArꢀH), 7.40 (1H, t, J=7.5 Hz, ArꢀH),
7.51 (2H, d, J=7.8 Hz, ArꢀH), 7.60 (2H, t, J=8.4 Hz, ArꢀH), 7.73 (2H, dd, J1=2.4 Hz, J2=7.1
Hz, ArꢀH), 7.85 (2H, t, J=7.1 Hz, ArꢀH), 8.06 (4H, dd, J1=3.6 Hz, J2=8.1 Hz, ArꢀH), 8.17
(2H, d, J=8.4 Hz, ArꢀH), 8.29 (1H, s, CH), 10.27 (1H, s, NH), 12.18 (1H, s, NH); 13C NMR
(DMSOꢀd6, 75 MHz) δ: 39.0 (NꢀCH3), 114.6 (ArꢀC), 115.0 (ArꢀC), 123.5 (ArꢀC), 124.3 (Arꢀ
C), 124.4 (ArꢀC), 125.0 (ArꢀC), 125.3 (ArꢀC), 126.1 (ArꢀC), 127.1 (ArꢀC), 128.3 (ArꢀC),
129.1 (ArꢀC), 129.2 (ArꢀC), 129.3 (ArꢀC), 129.5 (ArꢀC), 129.6 (ArꢀC), 129.8 (ArꢀC), 130.4
(ArꢀC), 130.4 (ArꢀC), 132.1 (ArꢀC), 133.1 (ArꢀC), 133.7 (ArꢀC), 134.7 (ArꢀC), 138.6 (ArꢀC),
139.9 (ArꢀC), 140.0 (ArꢀC), 140.5(ꢀN=C), 143.7 (C=N), 149.0 (C=NꢀN), 177.6 (C=S); MS
m/z (ES–): 597; HRꢀMS (ES–): calcd for C30H22ClN6O2S2 (MꢀH+), 597.0934; found,
597.0911.
N-(4-Chlorophenyl)-2-(4-(4-methyl-5,5-dioxido-3-phenylbenzo[e]pyrazolo[4,3-c][1,2]
thiazin-2(4H)-yl)benzylidene)hydrazine carbothioamide (4i)
Offꢀyellow powder; m.p.: 222 ºC; FTꢀIR (KBr) cmꢀ1: 3310, 3138, 2922 1602, 1508, 1463,
1
1347, 1263, 1181, 1059, 968, 835, 769; H NMR (DMSOꢀd6, 300 MHz) δ: 2.90 (3H, s, Nꢀ
CH3), 7.13 (1H, d, J= 6.9 Hz, ArꢀH), 7.47 (4H, dd, J1=8.7 Hz, J2=19.2 Hz, ArꢀH), 7.59 (5H, t,
J=8.7 Hz, ArꢀH), 7.67 (2H, d, J=8.1 Hz, ArꢀH), 8.05 (3H, d, J=7.1 Hz, ArꢀH), 8.18 (2H, d,
J=8.4 Hz, ArꢀH), 8.28 (1H, s, CH), 10.30 (1H, s, NH), 12.07 (1H, s, NH); 13C NMR (DMSOꢀ
d6, 75 MHz) δ: 38.7 (NꢀCH3), 120.5 (ArꢀC), 121.8 (ArꢀC), 123.4 (ArꢀC), 123.6 (ArꢀC), 124.3
(ArꢀC), 124.6 (ArꢀC), 125.2 (ArꢀC), 126.1 (ArꢀC), 127.0 (ArꢀC), 127.6 (ArꢀC), 127.9 (ArꢀC),
128.9 (ArꢀC), 129.1 (ArꢀC), 129.2 (ArꢀC), 129.4 (ArꢀC), 129.7 (ArꢀC), 129.8 (ArꢀC), 130.0
(ArꢀC), 130.3 (ArꢀC), 130.4 (ArꢀC), 130.5 (ArꢀC), 133.1 (ArꢀC), 134.8 (ArꢀC), 138.6 (ArꢀC),
139.6 (ArꢀC), 141.6 (ꢀN=C), 143.7 (C=N), 158.8 (C=NꢀN), 177.5 (C=S); MS m/z (ES–): 597;
HRꢀMS (ES–): calcd for C30H22ClN6O2S2 (MꢀH+), 597.0934; found, 597.0930.
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