Piperlongumine derived cyclic sulfonamides (sultams): Synthesis and in?vitro exploration for therapeutic potential against HeLa cancer cell lines

Article abstract of DOI:10.1016/j.ejmech.2016.12.022

A novel modification of piperlongumine is designed, bearing a cyclic sulphonamide (sultam) and its synthesis is described. For the first time herein we report the synthesis and biological evaluation of the natural product derived cyclic sulfonamides using Grubbs second generation catalyst (Grubbs II) via ring closing metathesis approach. Synthesis of a series of piperlongumine derived sultams is done in a moderate to good yield using Wittig reaction, Ring-Closing Metathesis (RCM) and, amide synthesis by using mixed anhydride, approach. All synthesized compounds were evaluated for anticancer activity and some demonstrated dose dependent reduction in HeLa cell growth. Of these 7, 10 and 14 significantly reduced the cell growth. Consequently their calculated GI₅₀values were found to be 0.1 or <0.1?μM.

Full text of DOI:10.1016/j.ejmech.2016.12.022

Accepted Manuscript
Piperlongumine derived cyclic sulfonamides (sultams): Synthesis and in vitro
exploration for therapeutic potential against HeLa cancer cell lines
Nitin P. Lad, Sarang Kulkarni, Rajiv Sharma, Malcolm Mascarenhas, Mahesh R.
Kulkarni, Shivaji S. Pandit
PII:
S0223-5234(16)31028-5
10.1016/j.ejmech.2016.12.022
EJMECH 9113
DOI:
Reference:
To appear in: European Journal of Medicinal Chemistry
Received Date: 22 September 2016
Revised Date: 19 November 2016
Accepted Date: 9 December 2016
Please cite this article as: N.P. Lad, S. Kulkarni, R. Sharma, M. Mascarenhas, M.R. Kulkarni, S.S.
Pandit, Piperlongumine derived cyclic sulfonamides (sultams): Synthesis and in vitro exploration for
therapeutic potential against HeLa cancer cell lines, European Journal of Medicinal Chemistry (2017),
doi: 10.1016/j.ejmech.2016.12.022.
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
Piperlongumine derived cyclic sulfonamides (sultams): synthesis
and in vitro exploration for therapeutic potential against HeLa
cancer cell lines.
Nitin P. Lada,b, Sarang Kulkarnib, Rajiv Sharmab, Malcolm Mascarenhasb, Mahesh R.
Kulkarnia,b , Shivaji S. Pandit a
a Research Centre and Post Graduate Department of Chemistry, Padmashri Vikhe Patil College
of Arts, Science and Commerce, Pravaranagar, A/P Loni, Tal. Rahata, Dist. Ahmednagar
413713, India.
b Department of Medicinal Chemistry, Piramal Enterprises Ltd., 1-Nirlon Complex, Goregaon
(East), Mumbai 400063, India.
O
O
O
S
O
O
N
O
GI50= 14
3
O
O O
S
O
O
O O
S
O
O
O
N
S
N
N
O
O
F
GI50= 0.1
10
GI50= <0.1
07
GI50= <0.1
14

ACCEPTED MANUSCRIPT
.
Piperlongumine derived cyclic sulfonamides (sultams): synthesis
and in vitro exploration for therapeutic potential against HeLa
cancer cell lines.
Nitin P. Lada,b, Sarang Kulkarnib, Rajiv Sharmab, Malcolm Mascarenhasb, Mahesh R.
Kulkarnia,b , Shivaji S. Pandit a
a
Research Centre and Post Graduate Department of Chemistry, Padmashri Vikhe Patil College
of Arts, Science and Commerce, Pravaranagar, A/P Loni, Tal. Rahata, Dist. Ahmednagar
413713, India.
b Department of Medicinal Chemistry, Piramal Enterprises Ltd., 1-Nirlon Complex, Goregaon
(East), Mumbai 400063, India.
† Electronic Supplementary Information (ESI) available: spectral data
*Author for correspondence
Dr. S. S. Pandit.
Post Graduate and Research centre, Department of Chemistry, Padmashri Vikhe Patil College of
Arts, Science and Commerce, Pravaranagar, A/P Loni, Tal. Rahata, Dist. Ahmednagar – 413713.
India.
E-mail:akankshapandit2002@yahoo.com,
Tel.; +91-9766959195

ACCEPTED MANUSCRIPT
.
ABSTRACT
A novel modification of piperlongumine is designed, bearing a cyclic sulphonamide (sultam) and
its synthesis is described. For the first time herein we report the synthesis and biological
evaluation of the natural product derived cyclic sulfonamides using Grubbs second generation
catalyst (Grubbs II) via ring closing metathesis approach. Synthesis of a series of
piperlongumine derived sultams is done in a moderate to good yield using Wittig reaction, Ring-
Closing Metathesis (RCM) and, amide synthesis by using mixed anhydride, approach. All
synthesized compounds were evaluated for anticancer activity and some demonstrated dose
dependent reduction in HeLa cell growth. Of these 7, 10 and 14 significantly reduced the cell
growth. Consequently their calculated GI50 values were found to be 0.1 or <0.1 µM.
KEYWORDS
piperlongumine (PL) derived cyclic sulfonamide (sultams), ring closing metathesis, anticancer,
GI50 values.

ACCEPTED MANUSCRIPT
.
1. Introduction
Natural products and their derivatives have always played a vital role in the
treatment of human health problems. There are various natural products / natural product derived
drugs in the market to treat various diseases. Natural products have continuously inspired drug
discovery chemists and have provided opportunities to incorporate novel structural scaffolds in
drug designing. A recent survey by Newman and Cragg clearly demonstrates the vital role of
natural products on drug development / human health [1]. Sulfonamides are one of the important
structural motifs present in various pharmacologically important molecules [2] and
agrochemicals / dyes [3] as it mimics the amide functionality by interacting with biological
targets in a similar fashion to an amide (Figure 1, structure I, II). But improved stability and
better PK properties of the sulfonamide functionality makes them one of the better replacements
for an amide group in designing novel peptidomimetic inhibitors [4] and small molecule
inhibitors. A few biologically active natural products containing a sulfonamide moiety have also
been reported in the literature (Figure 1, structure III, IV) [5,6]. Due to the biological
significance of the sulfonamide moiety researchers have also designed inhibitors by
incorporating the cyclic sulfonamide (sultam) functionality [7]. To the best of our knowledge
cyclic sulfonamides usually do not occur in nature, but various inhibitors / drugs containing the
cyclic sulfonamide (sultam) moiety are currently in the market and in various phases of clinical
trials (Figure 1, structure V, VI, VII and VIII) [8,9,10]. More importantly saccharin [11], an
artificial sweetening agent, also contains the cyclic sulfonamide moiety.
<< Figure 1 >>
Therefore, we were curious to see the effect of incorporation of sultam in a natural product and
to study whether the aforementioned modification is beneficial for biological activity. The
natural product piperlongumine (PL), isolated from the fruit of the long pepper (Piper longum), a
pepper plant found in southern India and southeast Asia, had attracted our attention as this
compound exhibits cytotoxicity selectively against cancer cell lines by elevating reactive oxygen
species (ROS) levels. It has been proposed that PL exhibits its biological effect by covalently
binding to its target. Schreiber and co-workers have synthesized various PL analogs [12,13] to
understand the role of each functional group of PL on the potency. PL contains an amide
functionality but has toxic effects and many researchers have studied the SAR by synthesizing
different analogues of PL and a plethora of literature is available. However to the best of our

ACCEPTED MANUSCRIPT
.
knowledge the replacement of amide to sulfonamide is not studied. Therefore we were curious to
see the change in the anticancer effect produced when amide is changed to sulfonamide.
In PL 5,6-dihydropyridin-2(1H)-one is joined to a 3,4,5-trimethoxyphenyl group via an E-
acryloyl group. It was assigned the structure, for the first time in 1968 [14]. Validating the
structure of PL through total synthesis and X-ray crystallographic structure determination was
reported in 1984 by Simonsen, who employed 3,4,5-trimethoxycinnamic anhydride in an amide
bond formation approach [15]. General methods for the synthesis of PL type structures involves
the condensation of an α, β-unsaturated δ-lactam with a variety of cinnamates [16]. Some PL
derivatives having anti-cancer activity were also synthesized by using Horner–Wadsworth–
Emmons coupling approach in good overall yield [17]. There are several SAR studies on PL
analogues and these mainly focus towards the modification of the heterocyclic
dihydropyrimidone region of the ligand, which itself has been implicated in depletion of ROS
levels in cells; and also the gluthionyl binding bridge of the olefinic region. There are fewer
reports on modification of the styryl region as compared to the dihydropyrimidone region. There
are a number of reports on the modification of the heterocyclic dihydropyrimidone region
present in PL. Many researchers have modified the amide ring present in piperlogumine by
increasing or decreasing the carbon chain as well as its substituent [12], but there are no reports
on the replacement of amide to sulfonamide. Sulfonamides are amide analogues in which
carbonyl (C=O) moiety is replaced with isosteric sulfonyl (SO2) group. In our previous work and
increasing interest in the area of cyclic sulfonamide, we have already reported the synthesis of
sultams and studies regarding the cyclization of aminoalcohols using base mediated (LAED and
n-BuLi) cyclisation of N-O dimesylate resulting in the formation of cyclic sulfonamides
(sultams) [7]. Sulfonamides are chemically more stable, as amides are hydrolyzed faster. Primary
sulfonamides and secondary sulfonamides contain two and one hydrogen atoms, respectively, on
the nitrogen. The natures of these hydrogens are acidic and their pKa is ~10 and their acidity is
also greater as compared to amides. If an electron withdrawing group is present on the nitrogen
then this makes it more acidic than the normal sulfonamides. In general cases sulfonamides are
relatively more stable and less reactive. However, sulfonamides either primary or secondary can
be made into more nucleophilic anions upon treatment with strong bases and these anions can be
involved in displacement reactions similar to that which the ionized amides react [18,19]. We
have decided to modify the amide ring to cyclic sulfonamide as no one has reported this before.

ACCEPTED MANUSCRIPT
.
There is a greater scope to work in this area and to introduce new scaffolds / derivatives of PL
and explore the biological properties.
2. Results and Discussion
2.1 Chemistry
In this synthesis of PL derived cyclic sulfonamides. During the synthesis of the PL analogues the
greatest synthetic challenge is the preparation of key starting material 5,6-dihydropyridin-2(1H)-
one (2). Using Grubbs second generation catalyst (Grubbs II) via ring closing metathesis (RCM)
approach, the corresponding N-(but-3-en-1-yl)ethenesulfonamide target compounds were
achieved via the synthetic route outlined in (Scheme 1, 2 and Figure 2).
<< Figure 2 >>
<< Scheme 1 >>
<< Scheme 2 >>
To
synthesize
compound
(E)-ethyl
3-(3,4,5-trimethoxyphenyl)acrylate,
3,4,5-
trimethoxybenzaldehyde was treated with ethyl 2-(triphenylphosphoranylidene)acetate (Wittig
0
reagent) from 0 C to ambient temperature in dichloromethane solvent for 16 hours to give the
corresponding (E)-ethyl 3-(3,4,5-trimethoxyphenyl)acrylate in a good yield [20]. Compound (E)-
ethyl 3-(3,4,5-trimethoxyphenyl)acrylate undergoes hydrolysis using lithium hydroxide in
ethanol, tetrahydrofuran and water as solvent at ambient temperature for 4 hours to give the
corresponding (E)-3-(3,4,5-trimethoxyphenyl)cinnamic acid with excellent yields. Using the
above same strategy gave various substituted cinnamic acids with good to excellent yields.
Synthesis of 1 involved formation of N-(but-3-en-1-yl)ethenesulfonamide. Treatment of 2-
chloroethanesulphonyl chloride in dichloromethane with dropwise addition of a premixed
solution of triethylamine and but-3-en-1-amine at -150C and then stirring at ambient temperature
for 16 hours yielded N-(but-3-en-1-yl)ethenesulfonamide (1) in excellent yield [21]. To
synthesize 2 we used the ring closing metathesis approach by using Grubbs second generation
catalyst (Grubbs II) catalyst. Compound 1 was treated with Grubbs II catalyst under an inert
atmospheric condition. Reaction mass was refluxed in dichloromethane for six hours to yield N-
(but-3-en-1-yl)ethenesulfonamide (2) in a excellent yield [16b]. Subsequently piperlongumine
derived cyclic sulphonamides (3 to 21) were synthesized by using the mixed anhydride approach
[22]. The mixed anhydride mainly contains a sterically hindered part of an acid or good leaving

ACCEPTED MANUSCRIPT
.
group in one half of the molecule. Cinnamic acids on treatment with pivaloyl chloride in THF at
0
-10 C for 45 minutes yielded the corresponding anhydrides. Compound 2 up on treatment with
0
n-Butyllithium at -40 C pulls out a proton from 3,4-dihydro-2H-1,2-thiazine 1,1-dioxide and
generates the corresponding anion. Then treatment with the corresponding acid anhydride
0
prepared as above or directly with acid chlorides and stirring this reaction at -40 C for 1 hour
yielded the corresponding PL derived cyclic sulfonamide analogues (3 to 21) in moderate to
good yield.
2.2 Biology
Cell viability of synthesized derivatives of piperlongumine derived cyclic sulfonamides were
determined by SRB assay using HeLa cervical cancer cells treated with various concentrations of
experimental drugs and the positive control, adriamycin, for 48 h. All 19 compounds evaluated
for anti cancer activity demonstrated dose dependent reduction in HeLa cell growth. Of these, 7,
10 and 14 significantly reduced the cell growth (Table 1, Fig. 3, and Fig. 4). At high
concentration, all the compounds exhibited cell kill as compared to starting population.
Consequently their calculated GI50 values were found to be <0.1µM (highlighted yellow; Table
2). Compounds with GI50 value of ≤ 10-6 (i.e. 1 µMolar) or ≤ 10 µg/ml are considered to
demonstrate activity, in case of pure compounds, as per NCI guidelines. Hence of 19 compounds
studied, 7, 10 and 14 were found to have significant anti-proliferative activity.
<< Table 1 >>
<< Figure 3>>
<< Figure 4 >>
<< Table 2 >>
Statistical analysis. Data are presented as the mean ± SEM. Statistical significance was
analyzed by two-way ANOVA using the GraphPad Prism software (version 5.01; La Jolla,CA,
USA). A p value lower than 0.0001 was considered statistically significant.
The SAR (structure- activity relationship) anticancer activity of PL derived cyclic sulfonamides
(sultams) against HeLa cancer cell lines (cervical cancer cell) are represented in Tables 1 and 2
respectively. The compounds 7, 10 and 14 exhibited promising anticancer activity. No particular

ACCEPTED MANUSCRIPT
.
trend as to the effect of substituent on the anticancer activity has been observed. In contrast to the
results of anticancer activity 7, 10 and 14 are from 2-methoxyphenyl, 3,5-dimethoxyphenyl and
3-fluorophenyl substituted PL derived cyclic sulfonamides derivatives (sultams). Thus, the PL
derived cyclic sulfonamides (sultams) derivatives bearing 2-methoxyphenyl, 3,5-
dimethoxyphenyl and 3-fluorophenyl. Remarkably, the 7, 10 and 14 are broad spectrum
anticancer activity against HeLa cancer cell lines. The other compound exhibited moderate to
low activity against HeLa cancer cell lines.
3. Conclusions
We have introduced PL derived cyclic sulfonamides (sultams) for the first time and
synthesized the PL analogues, and optimized the chemistry towards the synthesis of natural
product derived cyclic sulfonamide (sultams) and their analogues. All the compounds displayed
dose-dependent reduction of cell viability in HeLA cancer cell lines. However three compounds,
7, 10 and 14 showed higher efficiency and produced 50% cell growth inhibition at < 0.1 µM
concentration. The results of SRB assay thus show that some of the experimental drugs may
potentially serve as candidates for cervical cancer treatment. Further studies may lead to
identification of more potent compounds as anticancer agents.
4. Experimental
4.1 General
All the reagents and starting materials were obtained commercially and used without
purification. Nuclear magnetic resonance (1H and 13C NMR) spectra were recorded on Bruker
either 300 or 400 MHz FT-NMR (Advance DPX300) spectrometer (Faellandon, Switzerland) in
DMSO-d6 or CDCl3 using TMS as internal standard. Chemical shifts are reported in parts per
million (δ), coupling constants (J values) are reported in Hertz (Hz). ESI-MS were recorded on
Bruker Daltonics Micro TOF-Q spectrometer (Bremen, Germany). Analytical high pressure
liquid chromatography (HPLC) was performed on Shimadzu 2010 HPLC with SPD-M20A PDA.
HPLC conditions used for checking purity were: Ascentis C18 (50 x 4.6 mm, 3.5 µ) column;
mobile phase: A: ACN, B: 0.01M NH4Oac + 0.5% TEA, pH 5.0 with AcOH (Time/B%: 0/80,
6/20, 7/80, 10/80); flow rate: 1ml/min. and HEMOCHROM INTSIL, C18, 15.x 4.6mm, 5
MICRON column; mobile phase: A: ACN, B: 0.1% TFA; flow rate 1ml/min. All

ACCEPTED MANUSCRIPT
.
chromatographic purifications were performed with silica gel (60-120 mesh), whereas all TLC
(silica gel) development was performed on silica gel coated (Merck Kiesel 60F254, 0.2 mm
thickness) sheets. Flash chromatography was conducted on a Teledyne Isco advances
CombiFlash® Rf automated flash chromatography system (Lincoln , USA) equipped with a UV
variable dual-wavelength, software selectable, 200-360 nm using prefabricated ‘RediSep® Flash
Column silica’ columns (size according to requirements). THF was dried by distillation from
sodium and benzophenone ketyl. All other solvents were of laboratory grade.
HPLC solvents: A: Acetonitrile. B: 0.01MNH4OAc + 0.5% TEA, pH 5.0 with AcOH. B1:
0.1%TFA.
HPLC Columns: Column 1: Ascentis TM Express (50 x 4.6 mm I.D.), 2.7 µm operated at 1
ml/min, detection at 288 nm. Column 2: HEMOCHROM INTSIL, C 18, 150 x 4.6 mm, 5
MICRON, operated at 1 ml/min, detection at 276 nm.
HPLC Methods: Method A: mobile phase: A: ACN, B: 0.01M NH4Oac + 0.5% TEA, pH 5.0
with AcOH (Time/B%: 0/80, 6/20, 7/80, 10/80); flow rate: 1ml/min using column 1.
Method B: mobile phase: A: ACN, B: 0.1% TFA; flow rate 1ml/min using column 2.
4.2 Chemistry
General procedure for the Synthesis of N-(but-3-en-1-yl)ethenesulfonamide (1)
A 500 mL three neck round bottom flask is equipped with calcium chloride guard tube, addition
funnel, magnetic stirrer etc. Charge 100 mL dichloromethane and 2-chloroethanesulphonyl
chloride (0.122 mol) and stir this at -150C. Then add drop wise a premixed mixture of but-3-en-
1-amine (0.122 mol) and triethylamine (0.183 mol) in dichloromethane 140 mL at -150C. After
complete addition, the reaction mass was stirred at ambient temperature for 16 hours. TLC
showed complete consumption of starting material. Quenched the reaction mass in a mixture of
ice cold water (15mL) and dichloromethane (150 mL). Separate the organic layer and wash the
organic layer with 2 x 150 mL of water and brine, dry over sodium sulfate and concentrate to
dryness. Yield 18 g, 91%.
1
Yield: 91%; Yellow Oily compound; H-NMR (300 MHz, CDCl3): δ 2.30 (q, J = 6.6Hz, 2H),
3.09 (q, J = 6.6Hz, 2H), 4.37 (s, 1H), 5.13 (s, 1H), 5.18 (d, J = 3.6Hz, 1H), 5.61 (m, 1H), 5.99
(dd, J = 9.9Hz, 1H), 6.30 (d, J = 16.5Hz, 1H), 6.48 (dd, J = 9.9Hz, 1H).

ACCEPTED MANUSCRIPT
.
General procedure for the synthesis of 3,4-dihydro-2H-1,2-thiazine 1,1-dioxide (2)
To a solution of N-(but-3-en-1-yl)ethenesulfonamide (15g, 0.093mol) in anhydrous
dichloromethane (150mL) was added Grubbs-II catalyst (0.399g, 5mol %) and stirred at reflux
for 6 hrs. Then it was stirred for an additional one hour at room temperature in open air. Then the
reaction mass was filtered through a celite pad and the celite pad washed by 50 mL
dichloromethane. The DCM is concentrated and the residue directly adsorbed on silica gel (60-
120 mesh) and purified using combi-flash chromatography using petroleum ether/ ethyl acetate
(2:8) as an eluent to give product 10 g.
Yield: 80%; Off White solid; 1H-NMR (300 MHz, CDCl3): δ 2.28 (m, 2H), 3.69 (q, J = 6Hz,
2H), 4.38 (s, 1H), 6.51 (td, J = 3.6, 7.5Hz, 1H), 6.69 (td, J = 2.1, 4.5Hz, 1H); 13C-NMR(300
MHz, DMSO-d6): 23.32, 41.32, 129.52, 138.58.
General procedure for the Synthesis of (E)-1-(1,1-dioxido-3,4-dihydro-2H-1,2-thiazin-2-yl)-3-
substitutedphenylprop-2-en-1-one (3 to 21)
To a solution of substituted cinnamic acid (0.420 mmol) in freshly distilled THF (5mL) was
added triethyl amine (0.05 mL). To this reaction mixture, pivaloyl chloride (0.33 mmol) was
added at -100C and reaction was allowed to stir at -100C for 45 minutes. After completion of the
reaction, (monitored by TLC) this mixture was used for the next step without purification and
work up.
To a solution of 3,4-dihydro-2H-1,2-thiazine 1,1-dioxide (0.504 mmol) in freshly distilled THF
(5 mL) was added 1.2 equivalent n-BuLi (0.3mL) at -400C under inert atmospheric conditions
and the reaction was allowed to stir for one hour at -400C. Then add the anhydride prepared from
the above step. The reaction mixture was allowed to stir for 1 h at -400C. Then the reaction
mixture was quenched with saturated ammonium chloride (2 mL), and extracted with ethyl
acetate (15 mL). The organic layer was separated, washed with brine (2 X 15 mL), dried over
anhydrous Na2SO4. The organic layer was concentrated by distillation under reduced pressure to
afford a crude product which was purified using combiflash on silica gel (60-120 mesh) using
petroleum ether and ethyl acetate as eluent to gave a pale yellow solid (Yield 55-70%).
(E)-1-(1,1-dioxido-3,4-dihydro-2H-1,2-thiazin-2-yl)-3-(3,4,5-trimethoxyphenyl)prop-2-en-1-one
1
(3). Yield: 65 %; White solid; H-NMR(300 MHz, DMSO-d6): δ 2.46 (m, 2H,), 3.70 (s, 3H),

ACCEPTED MANUSCRIPT
.
3.82 (s, 6H), 4.20 (t, J = 5.4Hz, 2H), 6.73 (m, 1H), 6.98 (d, J = 10.8Hz, 1H), 7.27 ( d, J =
15.6Hz, 1H), 7.63 (d, J = 15.6Hz, 1H); 13C-NMR(300 MHz, DMSO-d6):24.69, 43.15, 56.45,
60.60, 106.33, 119.63, 128.99, 130.25, 140.17, 140.80, 145.11, 153.57, 165.32; MS (ESI) m/z:
352.2 [M-H]- ; HPLC Retention time: 5.215 min., Purity: 92.23% (Method A).
(E)-3-(2-chloroimidazo[1,2-a]pyridin-3-yl)-1-(1,1-dioxido-3,4-dihydro-2H-1,2-thiazin-2-
yl)prop-2-en-1-one (4). Yield: 62% ; White solid; 1H-NMR(300 MHz, DMSO-d6): δ 2.44 (tdd, J
= 15.6, 3.6, 1.5Hz, 2H), 4.24 (t, J = 5.7Hz, 2H), 6.77 (tt, J = 3.9, 14.4Hz, 1H), 7.01 (tt, J = 2.1,
12.6Hz, 1H), 7.25 (td, J = 1.2, 6.9Hz, 1H), 7.56 (td, J = 1.2, 1.8Hz, 1H), 7.64 (d, J = 15.6Hz,
1H), 7.72 (td, J = 0.9, 9Hz, 1H), 8.02 (d, J = 15.6Hz, 1H), 8.84 (tt, J = 1.2, 6.9Hz, 1H); 13C-
NMR(300 MHz, DMSO-d6): 24.71, 42.89, 115.31, 116.35, 116.43, 117.18, 126.32, 127.67,
128.97, 129.00, 138.60, 141.00, 144.95, 165.00; MS (ESI) m/z: 336.1 [M-H]- ; HPLC Retention
time: 8.405 min., Purity: 98.77% (Method B).
(E)-3-(4-chlorophenyl)-1-(1,1-dioxido-3,4-dihydro-2H-1,2-thiazin-2-yl)prop-2-en-1-one
(5).
Yield: 55%; Off white solid; 1H-NMR(300 MHz, DMSO-d6): δ 2.50 (m, 2H), 4.17 ( t, J =
5.1Hz, 2H), 6.75 (m, 1H), 6.99 (d, J = 10.5Hz, 1H), 7.36 (d, J = 15.3Hz, 1H), 7.53 (d, J = 8.1Hz,
2H), 7.63 (s, 1H), 7.72 (d, J = 8.7Hz, 2H); MS (ESI): m/z [M-H]- 296.1; HPLC Retention time:
6.239 min., Purity: 98.69% (Method A).
(E)-1-(1,1-dioxido-3,4-dihydro-2H-1,2-thiazin-2-yl)-3-(5-fluoro-1H-indol-3-yl)prop-2-en-1-one
1
(6). Yield: 58%; Yellow solid; H-NMR(300 MHz, DMSO-d6): δ 2..44 (tdd, J = 16.2, 3.9,
2.4Hz, 2H), 4.25 (t, J = 5.7Hz, 2H), 6.78 (tt, J = 3.6, 10.2Hz, 2H), 7.04 (tt, J =2.1, 10.5Hz, 1H),
7.50 (d, J = 15.6Hz, 1H), 7.64 (dd, J = 2.7, 9.6Hz, 1H), 7.80 (dd, J = 2.4, 9.3Hz, 2H), 8.04 (d, J
= 15.9Hz, 1H), 8.40 (d, J = 4.8Hz, 1H), 12.33 ( bs, 1H); MS (ESI): m/z [M-H]- 319.1; HPLC
Retention time: 6.050 min., Purity: 90.35% (Method A).

ACCEPTED MANUSCRIPT
.
(E)-1-(1,1-dioxido-3,4-dihydro-2H-1,2-thiazin-2-yl)-3-(2-methoxyphenyl)prop-2-en-1-one (7).
Yield: 64%; White solid; 1H-NMR(300 MHz, DMSO-d6): δ 2.42 (tdd, J = 19.2, 3.6, 1.5Hz, 2H),
3.87 (s, 3H), 4.20 (t, J = 5.7Hz, 2H), 6.75 (tt, J = 3.6, 14.1Hz, 1H), 6.95 (tt, J = 2.1, 12.1Hz,
1H), 7.04 (dd, J = 0.6, 7.5Hz, 1H), 7.13 (dd, J = 0.6, 8.1Hz, 1H), 7.44 (d, J = 12.9Hz, 1H), 7.47
(dd, J = 1.5, 15.6Hz, 1H), 7.62 (dd, J = 1.8, 7.8Hz, 1H), 7.89 (d, J = 15.6 Hz, 1H); 13C-NMR(300
MHz, DMSO-d6): 24.24, 42.46, 55.72, 118.89, 120.06, 120.74, 122.54, 128.45, 128.54, 128.93,
139.58, 140.45, 158.45, 158.14, 164.96; MS (ESI): m/z [M-H]- 292.1; HPLC Retention time:
9.114 min., Purity: 88.41% (Method B).
(E)-1-(1,1-dioxido-3,4-dihydro-2H-1,2-thiazin-2-yl)-3-(furan-3-yl)prop-2-en-1-one (8). Yield:
1
66%; Off white solid; H-NMR(300 MHz, DMSO-d6): δ 2.40 (tdd, J = 1.8, 3.9, 23.4Hz, 2H),
4.18 (t, J = 5.7Hz, 2H), 6.74 (tt, J = 3.9, 10.5Hz, 1H), 6.83 (dd, J = 0.6Hz, 1H), 6.98 (tt, J = 2.4,
10.2Hz, 1H), 7.06 (d, J = 15.3Hz, 1H), 7.63 (d, J = 15.6Hz, 1H), 7.77 (m, 1H), 8.16 (d, J =
0.3Hz, 1H) ; MS (ESI): m/z [M-H]- 252.1; HPLC Retention time: 8.215 min., Purity: 97.85%
(Method B).
(E)-1-(1,1-dioxido-3,4-dihydro-2H-1,2-thiazin-2-yl)-3-(thiophen-2-yl)prop-2-en-1-one
(9).
Yiled: 61%; Pale yellow solid;1H-NMR(300 MHz, DMSO-d6): δ 2.41 (tdd, J = 1.8, 3.6, 21.3Hz,
2H), 4.19 (t, J = 5.7Hz, 2H), 6.75 (tt, J = 3.9, 10.5Hz, 1H), 7.00 (tt, J = 2.1, 10.5Hz, 1H), 7.11 (d,
J = 15.3Hz, 1H), 7.18 (m, 1H), 7.57 (tt, J = 0.6, 3.6Hz, 1H), 7.77 (tt, J = 0.9, 5.1Hz, 1H), 7.90
(tt, J =0.6, 15.3Hz, 1H); MS (ESI): m/z [M-H]- 268.1; HPLC Retention time: 8.752 min., Purity:
88.25% (Method B).
(E)-3-(3,5-dimethoxyphenyl)-1-(1,1-dioxido-3,4-dihydro-2H-1,2-thiazin-2-yl)prop-2-en-1-one
(10). Yield: 66% white solid;1H-NMR(300 MHz, DMSO-d6): δ 2.41 (tdd, J = 2.1, 4.2, 18.6Hz,
2H), 3.74 (s, 3H), 3.81 (s, 3H), 4.20 (t, J = 5.7, 6.75Hz, 2H), 6.75 (tt, J = 3.9, 10.5Hz, 1H), 6.98
(tt, J = 2.1, 12.6Hz, 1H), 7.04 (d, J = 2.4Hz, 2H), 7.15 (d, J = 1.5Hz, 1H), 7.45 (d, J = 15.6Hz,
1H), 7.83 (d, J = 15.6Hz, 1H); 13C-NMR(300 MHz, DMSO-d6): 24.22, 42.50, 55.55, 56.09,
113.08, 113.57, 117.64, 120.60, 123.13, 128.55, 139.40, 140.41, 152.55, 153.13, 165.01; MS
(ESI): m/z [M-H]- 322.1; HPLC Retention time: 9.117 min., Purity: 96.64% (Method B).

ACCEPTED MANUSCRIPT
.
(E)-1-(1,1-dioxido-3,4-dihydro-2H-1,2-thiazin-2-yl)-3-(3-methoxyphenyl)prop-2-en-1-one (11).
Yield: 57%; White solid; 1H-NMR(300 MHz, DMSO-d6): δ 2.42 (tdd, J = 2.1, 3.9, 16.5Hz, 2H),
3.79 (s, 3H), 4.20 (t, J = 5.7Hz, 2H), 6.75 (tt, J = 3.9, 10.5Hz, 1H), 7.00 (tt, J = 2.1, 10.5Hz, 1H),
7.05 (dddd, J = 0.9, 2.7, 3.6, 11.7Hz, 1H), 7.26 (m, 2H), 7.35 (d, J = 6.9Hz, 1H), 7.39 (d, J =
7.8Hz, 1H); 13C-NMR(300 MHz, DMSO-d6): 24.21, 42.55, 55.24, 113.69, 116.40, 120.23,
120.45, 128.50, 130.17, 135.62, 140.48, 144.28, 159.63, 164.65; MS (ESI): m/z [M-H]- 292.2;
HPLC Retention time: 9.072 min., Purity: 93.58% (Method B).
(E)-1-(1,1-dioxido-3,4-dihydro-2H-1,2-thiazin-2-yl)-3-(4-nitrophenyl)prop-2-en-1-one
(12).
1
Yield: 63%; White solid; H-NMR(300 MHz, DMSO-d6): δ 2.47 (m, 2H), 4.22 (t, J = 5.4Hz,
2H), 6.75 (m, 1H), 7.01 (d, J = 10.2Hz, 1H), 7.51 (d, J = 15.6Hz, 1H), 7.77 (d, J =15.6Hz, 1H),
7.96 (d, J = 8.4Hz, 2H), 8.29 (d, J = 8.4Hz, 2H); 13C-NMR(300 MHz, DMSO-d6): 24.62, 43.08,
124.60, 128.84, 129.83, 141.07, 141.69, 148.58, 164.69; MS (ESI): m/z [M-H]- 307.1; HPLC
Retention time: 9.003 min., Purity: 98.20% (Method B).
(E)-1-(1,1-dioxido-3,4-dihydro-2H-1,2-thiazin-2-yl)-3-(2-fluorophenyl)prop-2-en-1-one
(13).
1
Yield: 56%; Off white solid; H-NMR(300 MHz, DMSO-d6): δ 2.42 (tdd, J = 2.1, 6.0, 18.3Hz,
2H), 4.21 (t, J = 5.4Hz, 2H), 6.76 (tt, J = 3.6, 10.5Hz, 1H), 7.01 (tt, J = 2.1, 10.2Hz, 1H), 7.35
(dd, J = 9.3, 16.8Hz, 2H), 7.48 (d, J = 15.9Hz, 1H), 7.55 (ddt, J = 5.7, 3.9, 7.8Hz, 1H), 7.71 (d, J
= 15.9Hz, 1H), 7.79 (ddd, J = 1.2, 7.5, 15.9Hz, 1H); MS (ESI): m/z [M-H]- 280.1; HPLC
Retention time: 6.933 min., Purity: 96.97% (Method A).
(E)-1-(1,1-dioxido-3,4-dihydro-2H-1,2-thiazin-2-yl)-3-(3-fluorophenyl)prop-2-en-1-one
(14).
1
Yield: 59%; Off white solid; H-NMR(300 MHz, DMSO-d6): δ 2.42 (tdd, J = 1.8, 3.3Hz, 2H),
4.20 (J = 5.7Hz, 2H), 6.75 (tt, J = 3.9, 10.5Hz, 1H), 7.00 (tt, J = 2.1, 10.5Hz, 1H), 7.29 (td, J =
1.2, 2.7Hz, 1H), 7.38 (d, J = 15.6Hz, 1H), 7.53 (m, 2H), 7.57 (tt, J = 1.2Hz, 8.1Hz, 1H), 7.67 (d,
J = 15.6Hz, 1H); 13C-NMR(300 MHz, DMSO-d6): 24.19, 43.54, 114.63, 117.79, 121.55, 124.42,
128.39, 131.01, 136.69, 140.34, 142.68, 160.80, 164.04; MS (ESI): m/z [M-H]- 280.1; HPLC
Retention time: 9.150 min., Purity: 83.95% (Method B).

ACCEPTED MANUSCRIPT
.
(E)-3-([1,1'-biphenyl]-3-yl)-1-(1,1-dioxido-3,4-dihydro-2H-1,2-thiazin-2-yl)prop-2-en-1-one
1
(15). Yield: 62%; Yellow solid; H-NMR(300 MHz, DMSO-d6): δ 2.45 (tdd, J = 2.4, 3.6,
12.3Hz, 2H), 4.22 (t, J = 5.4Hz, 2H), 6.76 (tt, J = 3.6, 10.5Hz, 1H), 7.00 (tt, J = 2.1, 10.5Hz,
1H), 7.41 (tt, J = 1.2, 8.4Hz, 1H), 7.52 (m, 3H), 7.52 (m, 3H), 7.65 (d, J = 6.3Hz, 1H), 7.76 (m,
5H), 7.95 (t, J = 1.5Hz, 1H); 13C-NMR(300 MHz, DMSO-d6): 24.23, 42.60, 120.38, 126.64,
126.89, 127.05, 127.86, 128.53, 129.03, 129.72, 134.92, 139.47, 140.48, 140.97, 144.25, 164.72;
MS (ESI): m/z [M-H]- 339.09; HPLC Retention time: 10.294 min., Purity: 93.04% (Method B).
(E)-1-(1,1-dioxido-3,4-dihydro-2H-1,2-thiazin-2-yl)-3-(3-(trifluoromethyl)phenyl)prop-2-en-1-
1
one (16). Yield: 64%; Yellow solid; H-NMR(300 MHz, DMSO-d6): δ 2.43 (tdd, 3.0, 5.1,
15.9Hz, 2H), 4.22 (t, J = 5.7Hz, 2H), 6.77 (tt, J = 3.9, 10.5Hz, 1H), 7.02 (tt, J = 2.1, 10.5Hz,
1H), 7.42 (d, J = 15.3Hz, 1H), 7.69 (t, J = 7.5Hz, 1H), 7.85 (m, 3H), 7.95 (d, J = 7.8Hz, 1H);
13C-NMR(300 MHz, DMSO-d6): 24.17, 42.65, 122.26, 124.50, 125.89, 126.26, 127.02, 128.36,
130.64, 132.43, 133.31, 138.11, 140.73, 164.10; MS (ESI): m/z [M-H]- 330.1; HPLC Retention
time: 9.702 min., Purity: 95.11% (Method B).
(E)-1-(1,1-dioxido-3,4-dihydro-2H-1,2-thiazin-2-yl)-3-(m-tolyl)prop-2-en-1-one (17). Yield:
1
57%; Off white solid; H-NMR(300 MHz, DMSO-d6): δ 2.34 (s, 3H), 2.42 (tdd, J = 2.1, 3.9,
16.8Hz, 2H), 4.20 (t, J = 5.7Hz, 2H), 6.75 (tt, J = 3.9, 10.5Hz, 1H), 7.00 (tt, J = 2.1, 10.5Hz,
1H), 7.36 (m, 3H), 7.48 (m, 2H), 7.66 (d, J = 15.6Hz, 1H); MS (ESI): m/z [M-H]- 276.2; HPLC
Retention time: 9.471 min., Purity: 95.70% (Method B).
(1,1-dioxido-3,4-dihydro-2H-1,2-thiazin-2-yl)(4-methyl-3-nitrophenyl)methanone (18). Yield:
60%; Yellow solid; 1H-NMR(300 MHz, DMSO-d6): δ 2.49 (tdd, J = 1.8, 3.6, 16.8Hz, 2H), 2.59
(s, 3H), 4.21 (t, J = 5.7Hz, 2H), 6.78 (tt, J = 3.9, 10.5Hz, 1H), 6.93 (tt, J = 2.4, 10.5Hz, 1H), 7.65
(d, J = 8.1Hz, 1H), 7.88 (dd, J = 1.8, 7.8Hz, 1H), 8.20 (d, J = 1.8Hz, 1H); 13C-NMR(300 MHz,
DMSO-d6): 19.74, 23.95, 44.45, 124.74, 127.98, 132.76, 133.11, 134.41, 137.26, 140.50,
148.23, 168.00; MS (ESI): m/z [M-H]- 295.1; HPLC Retention time: 8.535 min., Purity: 97.65%
(Method B).
(3-chlorophenyl)(1,1-dioxido-3,4-dihydro-2H-1,2-thiazin-2-yl)methanone (19).

ACCEPTED MANUSCRIPT
.
1
Yield: 64%; Yellow solid; H-NMR(300 MHz, DMSO-d6): δ 2.57 (tdd, J = 1.8, 3.6, 14.1Hz,
2H), 4.18 (t, J = 5.7Hz, 2H), 6.76 (tt, J = 3.6, 10.5Hz, 1H), 6.91 (tt, J = 2.1, 10.5Hz, 1H), 7.41
(m, 4H); MS (ESI): m/z [M-H]- 272.1; HPLC Retention time: 8.083 min., Purity: 97.73%
(Method B).
(E)-1-(1,1-dioxido-3,4-dihydro-2H-1,2-thiazin-2-yl)-3-(4-methoxyphenyl)prop-2-en-1-one (20).
1
Yield: 66%; Off white solid; H-NMR(300 MHz, DMSO-d6): δ 2.41 (tdd, J = 2.1, 3.9, 19.8Hz,
2H), 3.80 (s, 3H), 4.19 (t, J = 5.7Hz, 2H), 6.74 (tt, J = 3.6, 10.5Hz, 1H), 6.95 (m, 1H), 6.98 (d, J
= 1.8Hz, 1H), 7.02 (d, J = 8.7Hz, 1H), 7.22 (d, J = 15.6Hz, 1H), 7.65 (m, 3H); 13C-NMR(300
MHz, DMSO-d6): 24.23, 42.48, 55.41, 114.37, 116.51, 126.80, 128.56, 129.99, 140.40, 144.52,
161.42, 164.78; MS (ESI): m/z [M-H]- 292.2; HPLC Retention time: 6.403 min., Purity: 98.13%
(Method A).
(E)-1-(1,1-dioxido-3,4-dihydro-2H-1,2-thiazin-2-yl)-3-(p-tolyl)prop-2-en-1-one (21). Yield:
1
62%; White solid; H-NMR(300 MHz, DMSO-d6): δ 2.34 (s, 3H), 2.41 (tdd, J = 2.1, 3.9,
18.6Hz, 2H), 4.20 (t, J = 5.7Hz, 2H), 6.75 (tt, J = 3.9, 10.5Hz, 1H), 6.99 (tt, J = 2.1, 10.5Hz,
1H), 7.28 (d, J = 7.8Hz, 1H), 7.31 (d, J = 15.6Hz, 1H), 7.58 (m, 3H), 7.67 (d, J = 15.6Hz, 1H);
13C-NMR(300 MHz, DMSO-d6): 21.09, 24.22, 42.49, 118.65, 128.23, 129.54, 131.48, 140.18,
140.46, 143.98, 144.55, 164.69; MS (ESI): m/z [M-H]- 276.2; HPLC Retention time: 6.459 min.,
Purity: 99.69% (Method A).
4.3 Biological assay:
Cell Culture
Human cervix carcinoma cells HeLa (Source: NCI, USA) were maintained in RPMI 1640
medium containing 10% fetal bovine serum and 2 mM L-glutamine in a 37°C humidified
atmosphere containing 5% CO2.
Evaluation of anti-cancer activity of compounds by SRB Assay
Anti-cancer activity of synthesized PL derived cyclic sulfonamide compounds was evaluated
using Hela cells by sulforhodamine B (SRB) colorimetric assay. The basis of this assay is the
ability of SRB to bind to or release from cellular proteins at differing pH values (Skehan et al
1990). Experimental drugs were solubilized in DMSO to prepare stock of 10-2 M. 5,000 cells/

ACCEPTED MANUSCRIPT
.
well were placed in a 96-well culture plates and incubated overnight. Cells were then treated
with experimental drugs at final concentration ranging from 10-4 to 10-7 M in growth medium for
48 hours. Adriamycin was used as positive control. SRB assay was carried out as described by
Vichai and Kirtikara, (2006) and Skehan et al, (1990). After 48 hours of incubation, the cells
were fixed with 10% trichloroacetic acid and stained with 0.4% SRB (Company) for 20 min. The
excess dye was removed by washing repeatedly with 1% acetic acid, and then the protein-bound
dye was dissolved in 10mM Tris base solution for examination of the optical density at 540 nm
using an ELISA plate reader. The % of control cell growth was corrected for the cell count at
time zero (start of drug exposure) and follows the following equation:
100×(T–T0)/(C–T0) in which T is the OD after exposure to a certain concentration of a drug, T0
is the OD at the start of drug exposure, and C is the OD of the control. The graph of average %
of cell growth against molar drug concentration for each drug was plotted and the concentration
showing 50% inhibition of cell growth was taken as GI50 [23, 24].
5. Acknowledgements
The authors are thankful to Dr. K V Rao, Medicinal Chemistry Department as well as Analytical
Department, Piramal Enterprises Ltd. Mumbai 400063 for providing infrastructural facilities.
SSP thanks UGC, New Delhi, India and Principal Padmashri Vikhe Patil College of Arts,
Science and Commerce, Pravara Nagar, 413713 and Advanced Centre for Treatment, Research
and Education in Cancer (ACTREC) Kharghar, Navi Mumbai-410210 for biological activity.
6. References
1) D. J. Newman, G. M. Cragg, Natural Products As Sources of New Drugs over the 30 Years
from 1981 to 2010, J. Nat. Prod.75 (2012) 311-335.
2) A.K. Ghosh, Z. L. Dawson, H. Mitsuya, Darunavir, a conceptually new HIV-1 protease
inhibitor for the treatment of drug-resistant HIV, Bioorg. Med.Chem. 24 (2007) 7576-7580.
3) G. Gervasio, D. Marabello F. Bertolotti, 4-({4-[Bis(2-cyanoethyl)amino]phenyl}-
diazenyl)benzenesulfonamide, Acta Cryst. E67 (2011) o231.
4) F. Lebon, M. Ledecq, Approaches to the Design of Effective HIV-1 Protease Inhibitors,
Curr. Med. Chem. 7 (2000) 455-477.

ACCEPTED MANUSCRIPT
.
5) A.S. Kende, K. Liu, K. M. Jos Brands, Total Synthesis of (-)-Altemicidin: A Novel
Exploitation of the Potier-Polonovski Rearrangement, J. Am. Chem. Soc.117 (1995) 10597–
10598.
6) S. K. Kottakota, M. Benton, D. Evangelopoulos, J. D. Guxman, S. Bhakta, T. D. McHugh, M.
Gray, P. W. Groundwater, Ec. L. Marrs, J. D. Perry, J. Harburn, Versatile Routes to Marine
Sponge Metabolites through Benzylidene Rhodanines, Org. Lett. 14 (2012) 6310–6313.
7) N. Lad, R. Sharma, V. Marquez, M. Mascarenhas, A new synthesis of sultams from amino
alcohols, Tetrahedron Lett.54 (2013) 6307-6309.
8) J. M. Hansen. M. Krisstensen. M, L. Skovsted, Sulthiame (Ospolot) as inhibitor of
diphenylhydatoin metabolism, Epilepsia. 9 (1968) 17–22.
9) T. J. Carty, A. Marfat, P. F. Moore, F.C. Falkner, T. M. Twomey, A. Weissman,
Ampiroxicam, an anti-inflammatory agent which is a prodrug of piroxicam, Agents Actions. 39
(1993) 157–165.
10) M. Inagaki, T. Tsuri, H. Jyoyama, T. Ono, K. Yamada, M. Kobayashi, Y. Hori, A. Arimura,
K. Yasui, K. Ohno, S. Kakudo, K. Koizumi, R. Suzuki, M. Kato, S. Kawai, S. Matsumoto, Novel
Antiarthritic Agents with 1,2-Isothiazolidine-1,1-dioxide (γ-Sultam) Skeleton: Cytokine
Suppressive Dual Inhibitors of Cyclooxygenase-2 and 5-Lipoxygenase, J. Med. Chem. 43 (
2000) 2040–2048.
11) D. J. Ager, D. P. Pantaleone, S. A. Henderson, A. R. Katritzky, I. Prakash, D. E. Walters,
Commercial, Synthetic Nonnutritive Sweeteners, Angew. Chem., Int. Ed. Engl. 37 (1998) 1802-
1817.
12) a) D. J. Adams, M. Dai, G. Pellegrino, B. K. Wagner, A. M. Stern, A. F. Shamji, S. L.
Schreiber, Synthesis, cellular evaluation, and mechanism of action of piperlongumine analogs,
Proc Natl Acad Sci U S A, 109, (2012) 15115-15120. b) Y. H. Seo, J-K, Kim, J-G. Jun,
Synthesis and biological evaluation of piperlongumine derivatives as potent anti-inflammatory
agents, Bioorg. Med. Chem. Lett. 24 (2014) 5727-5730. c) S. R. Punganuru, H. R. Madala, S. N.
Venugopal, R. Samala, C. Mikelis, K. S. Srivenugopal, Design and synthesis of a C7-aryl
piperlongumine derivative with potent antimicrotubule and mutant p53-reactivating properties,
Eur. J. Med. Chem. 107 (2016) 233-244. d) M. J. Meegan, S. Nathwani, B. Twamley, D. M.
Zisterer, N. M. O’Boyle, Piperlongumine (Piplartine) and Analogues: Antiproliferative
Microtubule-Destabilising Agents, Eur. J. Med. Chem. 125, 2017, 453-463. e) N. Nandakumar,

ACCEPTED MANUSCRIPT
.
S. Muthuramanb, P. Gopinath, P. Nithyab, J. Gopas, R. S. Kumar, Synthesis of Coumaperine
derivatives: their NF-κB inhibitory effect, inhibition of cell migration and their cytotoxic
activity, Eur. J. Med. Chem. 125, 2017, 1076-1087.
13) Z. V. Boskovic, M. M. Hussain, D. J. Adams, M. Dai, S. L. Schreiber, Synthesis of piperlogs
and analysis of their effects on cells, Tetrahedron, 69 (2013) 7559-7567.
14) B. S. Joshi, Y. N. Kamat, A. K. Saksena, On the structure of piplartine and a synthesis of
dihydropiplartine, Tetrahedron Lett. 9 (1968) 2395–2400.
15) P. M. Boll, J. Hansen, O. Simonsen, Synthesis and molecular structure of piplartine
(piperlongumine), Tetrahedron, 40 (1984) 171–175.
16) a) Y. Wang, J. Wang, J. Li, Y. Zhang, W. Huang, J. Zuo, H. Liu, D. Xie, P. Zhu, Design, Synthesis
and Pharmacological Evaluation of Novel Piperlongumine derivative as Potential Antiplatelet
Aggregation Candidate, Chem. Biol. Drug Des. 87 (2016) 833–840. b) V. R. Rao, P. Muthenna, G.
Shankaraiah, C. Akileshwari, K. H. Babu, G. Suresh, K. S. Babu, R. S. C. Kumar, K. R. Prasad,P. A.
Yadav, J. M. Petrash, G. B. Reddy, J. M. Rao, Synthesis and biological evaluation of new
piplartine analogues as potent aldose reductase inhibitors (ARIs), Eur. J. Med. Chem. 57 (2012)
344–361.
17) Li-C. Han, P. A. Stanley, P. J. Wood, P. Sharma, A. I. Kuruppu, T. D. Bradshaw, J. E.
Moses, Horner–Wadsworth–Emmons approach to piperlongumine analogues with potent anti-
cancer activity, Org. Biomol. Chem. 14 (2016) 7585-7593.
18) L. M. Lima, E. J. Barreiro, Bioisosterism: A Useful Strategy for Molecular Modification and
Drug Design, Current Medicinal Chemistry, 12 (2005) 23-49.
19) J. DeRuiter, AMIDES AND RELATED FUNCTIONAL GROUPS, Principles of Drug
Action 1, Spring 2005, Amides.
20) S. Kumar, R. Sharma, V. A. Mahajan, S. P. Sawargave, Phenyl alkanoic acid derivatives as
GPR agonists, WO2013128378A1, 2013
21) V. O. Rogachev, P. Metz, Thermal and high pressure intramolecular Diels-Alder reaction of
vinylsulfonamides, Nat Protoc. 6 (2006) 3076-3087.
22) H. S. Rho, H. S. Baek, D. H. Kim, I. S. Chang, A Convenient Method for the Preparation of
Alkanolamides, Bull. Korean Chem. Soc. 27 (2006) 584-586.
23) V. Vichai, K. Kirtikara, Sulforhodamine B colorimetric assay for cytotoxicity screening,
Nature Protocols, 1 (2006) 1112-1116

ACCEPTED MANUSCRIPT
.
24) P. Skehn, R. Storeng, A. Scudiero, J. Monks, D. McMohan, D. Vistica, T. W. Jonathan, H.
Bokesch, S. Kenney, M. R. Boyd, New colorimetric cytotoxicity assay for anticancer drug
screening, J. Natl. Cancer Inst. 82 (1990) 1107-1112.

ACCEPTED MANUSCRIPT
.
Figures, Tables and Schemes
Figure 1: A (Drugs and dyes containing sulfonamide moiety), B (Naturally occurring
sulphonamides), C (Drugs/ Clinical candidate and artificial sweetener containing cyclic
sulfonamides (sultams)).
Figure 2: Retrosynthetic approach towards synthesis of natural product derived sultams.
Scheme 1: Synthesis of piperlongumine derived cyclic sulfonamides (sultams) (3 to 17 and 20 to
21).
Scheme 2: Synthesis of PL derived cyclic sulfonamides by using different substituted acid
chlorides (18 and 19).
Table 1: Values depict cell growth of experimental and positive control drugs by SRB assay.
Experiment was repeated three times and values are mean of % growth values. Highlighted
values indicate significant anti-proliferative activity of compounds against MCF-7 cells.
Figure 3: SRB assay of HeLa cells treated with different concentrations of 3 to 12.
Figure 4: SRB assay of HeLa cells treated with different concentrations of 13 to Adriamycin.
Table 2: GI50 values of experimental compounds in comparison with adriamycin

ACCEPTED MANUSCRIPT
.
Figure 1: A (Drugs and dyes containing sulfonamide moiety), B (Naturally occurring
sulphonamides), C (Drugs/ Clinical candidate and artificial sweetener containing cyclic
sulfonamides (sultams))

ACCEPTED MANUSCRIPT
.
Figure 2 Retrosynthetic approach towards synthesis of natural product derived sultams.

ACCEPTED MANUSCRIPT
.
Scheme 1: Synthesis of piperlongumine derived cyclic sulfonamides (sultams).
0
Reagents and conditions: (a) DCM, 0 C to rt, 16h, 85%; (b) LiOH, EtOH, THF, water, rt, 4h,
0
90%; (c) DCM, TEA, 0 C to reflux, 6h, 91%; (d) Grubbs’ II catalyst, DCM, rt, 6h, 80%;(e)
pivaloyl chloride, THF, TEA, -10 0C, 45 min; (f) n-BuLi, THF, -40 0C to rt, 1h, 55-70%.

ACCEPTED MANUSCRIPT
.
Scheme 2: Synthesis of PL derived cyclic sulfonamides by using different substituted acid
chlorides (18 and 19).
Reagents and conditions: (a) n-BuLi, THF, -40 0C to rt, 1h, 55-70%.

ACCEPTED MANUSCRIPT
.
Table 1: Values depict cell growth of experimental and positive control drugs by SRB assay.
Experiment was repeated three times and values are mean of % growth values. Highlighted
values indicate significant anti-proliferative activity of compounds against MCF-7 cells.
Human Cervix Cancer Cell Line HeLa
% of Control Cell Growth
Molar Drug Concentrations
Average Values
10-7M
79.8
87.0
90.7
90.4
76.7
92.0
92.1
82.5
90.8
100.0
78.5
96.8
97.6
95.5
99.9
97.1
100.0
84.7
10-6M
71.4
59.0
80.2
87.6
35.0
80.2
74.2
32.5
92.2
90.4
62.3
42.4
86.5
86.3
89.5
93.7
86.7
83.8
10-5M
46.8
20.6
53.5
25.3
14.6
57.7
53.4
-60.1
68.7
59.0
52.4
-39.2
32.9
34.9
35.0
67.6
55.4
68.1
10-4M
-80.6
-78.5
-30.5
-48.0
-80.1
-78.1
-75.3
-78.4
-79.7
-71.6
-75.3
-69.0
-63.0
-64.8
-67.1
-11.2
10.8
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
-55.3

ACCEPTED MANUSCRIPT
.
86.8
81.4
26.3
-33.5
-84.6
21
ADR
-76.8
-82.9
-84.1

ACCEPTED MANUSCRIPT
.
Figure 3: SRB assay of HeLa cells treated with different concentrations of 3 to 12.
Growth Curve: Human Cervix Cancer Cell Line HeLa
100
50
0
10-7M
10-6M
10-5M
10-4M
-50
-100
Molar Drug Concentration
3
8
4
9
5
6
7
10
11
12

ACCEPTED MANUSCRIPT
.
Figure 4: SRB assay of HeLa cells treated with different concentrations of 13 to Adriamycin.
Growth Curve: Human Cervix Cancer Cell Line HeLa
100
50
0
10-7M
10-6M
10-5M
10-4M
-50
-100
Molar Drug Concentration
13
18
14
19
15
20
16
21
17
ADR

ACCEPTED MANUSCRIPT
.
Table 2: GI50 values of experimental compounds in comparison with adriamycin.
µM drug concentration from graph
14.3
8.2
3
4
26.4
18.8
0.1
5
6
7
20.3
18.8
<0.1
23.7
24.4
13.7
<0.1
19.83
19.55
20.73
39.25
45.4
24.4
18.6
<0.1
8
9
10
11
12
13
14
15
16
17
18
19
20
21
ADR