Diminutive effect on T and B-cell proliferation of non-cytotoxic α-santonin derived 1,2,3-triazoles: A report

Article abstract of DOI:10.1016/j.ejmech.2012.12.018

α-Santonin derived new series of 1,2,3-triazoles synthesized through Azide-Alkyne Huisgen 1,3-dipolar cycloaddition reaction between substituted aryl azide and a propargylated α-desmotrosantonin were bio-evaluated for their diminutive effect on ConA induced T-cell and LPS induced B-cell proliferation. Interestingly, most of the synthesized compounds showed better immunosuppressant activity than α-santonin. Triazole derivatives 9, 10, 17, 18, 29, and 30 displayed significant diminutive effect on cell proliferation. Compounds 12 and 13 were found selective against ConA T-cell proliferation exhibiting >90% inhibition at 1 × 10^-6 M concentration. The present study resulted in identification of several triazole derivatives as effective immunosuppressive agents.

Full text of DOI:10.1016/j.ejmech.2012.12.018

European Journal of Medicinal Chemistry 60 (2013) 365e375
Contents lists available at SciVerse ScienceDirect
European Journal of Medicinal Chemistry
journal homepage: http://www.elsevier.com/locate/ejmech
Original article
Diminutive effect on T and B-cell proliferation of non-cytotoxic
a-santonin derived 1,2,3-triazoles: A report
,
a
a
b
Praveen K. Chinthakindi a, Payare L. Sangwan a , Saleem Farooq , Rajeshwar R. Aleti , Anupurna Kaul ,
*
Ajit K. Saxena b, Y.L.N. Murthy c, Ram A. Vishwakarma a, Surrinder Koul a
,
*
a Bioorganic Chemistry Division, CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu 180001, India
b Cancer Pharmacology Division, CSIR-Indian Institute of Integrative Medicine, Jammu 180001, India
c Department of Organic Chemistry, Food, Drugs and Water, Andhra University, Visakhapatnam 530003, India
a r t i c l e i n f o
a b s t r a c t
Article history:
a
-Santonin derived new series of 1,2,3-triazoles synthesized through AzideeAlkyne Huisgen 1,3-dipolar
cycloaddition reaction between substituted aryl azide and a propargylated -desmotrosantonin were
bio-evaluated for their diminutive effect on ConA induced T-cell and LPS induced B-cell proliferation.
Interestingly, most of the synthesized compounds showed better immunosuppressant activity than
Received 30 August 2012
Received in revised form
16 November 2012
Accepted 8 December 2012
Available online 17 December 2012
a
a
-
santonin. Triazole derivatives 9, 10, 17, 18, 29, and 30 displayed significant diminutive effect on cell
proliferation. Compounds 12 and 13 were found selective against ConA T-cell proliferation exhibiting
>90% inhibition at 1 ꢀ 10ꢁ6 M concentration. The present study resulted in identification of several
triazole derivatives as effective immunosuppressive agents.
Keywords:
a
a
-Santonin
-Desmotroposantonin-1,2,3-triazoles
Ó 2012 Elsevier Masson SAS. All rights reserved.
Immunosuppressant
ConA
LPS
1. Introduction
the treatment of autoimmune diseases such as systemic lupus
erythematosus, rheumatoid arthritis, glomerulonephritis, and
Natural products (NPs) from plant, microbial and mammalian
source have been a reliable and constant source of therapeutic
agents for the use in humans, besides affording rich source of
nutraceuticals and food supplement and the quest to swell these
numbers goes unabated [1]. While the discovery of natural prod-
ucts penicillin and lovastatin led to development of new drug
armamentariums, tailoring of many natural product scaffolds by
the chemists has proved equally rewarding in the development of
some of the most effective drugs such as antidiabetic drug met-
formin (from galgine), hypertensive drug verapamil (from papav-
erine), and anti-asthmatic drug sodium cromoglycate (from
khellin). The role of NPs and/or natural product scaffolds shall
continue to play a highly significant role in the drug discovery and
development process for the treatment of human diseases [2e4].
Immunosuppressant is an imperative class of clinical drugs for
an array of medical processes, including transplant rejection and
psoriasis [5e7]. The FDA approval of cyclosporine (CsA) in 1983 was
a milestone in organ transplantation. T-lymphocytes play an inte-
gral role in transplant rejection and autoimmune diseases [8].
Several natural products from plants and microorganisms (Fig. 1)
are reported with clinically important therapeutic immunosup-
pressant activity [7,9e12]. Although immunosuppressive drugs
have been used in clinic for organ transplantation and treatment of
autoimmune diseases, their side effects including liver toxicity,
renal toxicity, infection, malignancy, and others cannot be neglec-
ted [13e18]. Thus, there is a pressing need for novel potential
immunosuppressive agents with high efficacy and low toxicity.
a-Santonin (1), from Artemisia species has been used extensively
in traditional Indian and Chinese medicine for the treatment of
inflammation and other conditions [19]. This NP and its derivatives
prepared through different synthetic routes have been found active
against various human cancer cell lines and many of them showing
more potency than the parent molecule [20e22] besides having
antipyretic activity [23]. Its derivatives such as cyclic peroxide and
BIOS-based libraries are reported to possess antimalarial activity
(ED50 ¼ 728.59 ng/mL) [24] and 5-lipoxygenase inhibitory activity
* Corresponding authors. Tel.: þ91 191 2569021; þ91 191 2569001 to 11x232/
371; fax: þ91 191 2569333.
E-mail addresses: plsangwan@iiim.ac.in (P.L. Sangwan), skoul@iiim.ac.in,
surrinderkoul@gmail.com (S. Koul).
(IC50 ¼ 0.8
mM) [25,26] (Fig. 2).
0223-5234/$ e see front matter Ó 2012 Elsevier Masson SAS. All rights reserved.
http://dx.doi.org/10.1016/j.ejmech.2012.12.018

366
P.K. Chinthakindi et al. / European Journal of Medicinal Chemistry 60 (2013) 365e375
HO
HO
N
O
O
O
O
O
O
H
N
H
O
H
N
H
O
N
N
N
N
O
N
N
N
O
O
O
O
O
O
N
N
N
N
H
H
N
O
N
O
O
N
N
N
H
N
H
N
H
N
H
O
O
O
O
Cyclosporine A
ISA-247
HO
O
O
O
H
N
O
O
OH
O
O
O
OH
O
N
N
O
N
N
O
O
O
O
N
H
N
O
O
O
HO
O
O
HO
N
O
Tacrolimus
Sirolimus
N
AEB071
CF3
OH
O
O
N
N
Cl
O
CN
O
O
O
NH
OCH3
HO
HO
O
NH3
N
CH3
Mycophenolate Mofetil
N
H
N
N
O
CP-690550
Leflunomide
FTY-720
Fig. 1. Some of the selected potent immunosuppressant agents.
In the present study, the unexplored immunosuppressant
property of -santonin derived -desmotroposantonin 1,2,3-
triazole analogues carrying diverse chemical features at N-1 posi-
tion have been investigated. Huisgen 1,3-dipolar cycloaddition
reaction has gained interest due to interesting biological activity of
1,2,3-triazoles [27e31].
a-desmotroposantonin (3). Propargylated a-desmotroposantonin
a
a
(4) obtained by propargylation [33] of 3 was subjected to Copper(I)-
catalyzed one pot cycloaddition reaction (click chemistry strategy)
with various substituted aromatic azides generated in situ by aryl
boronic acids in methanol and water (1:1) in the presence of
sodium ascorbate (reducing agent) [34] to give 1,2,3-triazol-1-yl
desmotroposantonin derivatives (5e31) in excellent yields
(Scheme 1). All the synthesized compounds (2e31) were charac-
terized by 1H NMR, 13C NMR, IR, and HRMS spectroscopic analysis.
2. Result and discussion
2.1. Chemistry
2.2. Biology
In the present study, a-santonin 1 isolated from the aerial part of
Artemisia laciniata was used as the starting material. The NP was
subjected to rearrangement [32] with Ac2O/H2SO4 to get acetyl
a
-Santonin (1), its A-ring rearranged derivative (A-ring
aromatized) bearing C-3-acetyl group (2), the deacetylated
product (3), and compound 4 (the propargylated derivative of 3)
were tested for cell proliferation against ConA induced T-cell and
LPS induced B-cells (Table 1). In comparison to the parent
compound 1, compound 2 displayed enhanced bioactivity against
LPS induced B-cell proliferation in a dose dependent manner. It
showed least cytotoxicity which was also observed in the parent
molecule. The compound however, showed no inhibition against
ConA induced T-cell proliferation. No diminutive effect against the
two mitogens was observed for compound 3, but in case of
compound 4 (which showed cytotoxicity) only LPS induced B-cell
a
-desmotroposantonin (2) which on deacetylation afforded
O
H
O
O
S
O
O
N
H
N
O
Santonin endo peroxide
Santonin derived amide
Fig. 2. Bioactive analogues of santonin.

P.K. Chinthakindi et al. / European Journal of Medicinal Chemistry 60 (2013) 365e375
367
Ac2O, conc. H2SO4
0 0C, 89%
Ammonia:CH3OH (1:1)
25 0C, 92%
O
AcO
HO
O
O
O
O
O
O
O
1
3
2
Br
K2CO3, (CH3)2CO
Reflux, 96%
R-B(OH)2, NaN3, MeOH:H2O (1:1)
CuSO4, Sod. Ascorbate
N
O
O
N
N
O
R
O
5-32
4
O
O
O
OH
O
O
8
5
6
7
9
O
NO2
O
O
O
10
13
11
12
14
F
I
I
I
F
Br
F
17
16
Br
18
19
15
F
5-31 R=
Br
O
O
Cl
O
I
Br
Br
F
F
20
21
22
24
23
Br
N
F3C
O
Br
26
Cl
25
Br
28
27
O
NH2
NH
CHO
O
29
30
31
Scheme 1. Synthesis of substituted aryl 1,2,3-triazole a-desmotroposantonin chemical entities.
proliferation was observed. The 1,2,3-triazoles anchored through
OH functionality at C-3 position of 1 were evaluated against the
two mitogens. Among triazoles, compounds 5, 6 and 11 bearing
unsubstituted aryl moiety at N-1 position were found having
insignificant activity besides being cytotoxic. For compounds 7,
12e18, 25, 26, and 28e31 with halo, nitro, alkyloxy, halo alkyl and
hydroxyl group/s in the aryl part of the molecule (encompassing
both electron donating and withdrawing groups) showed variable
proliferation effect against the two mitogens. Compound 7 dis-
played marginal LPS induced B-cell proliferation effect. While
compounds 12 and 13 showed high degree of selectivity for T-cell
lymphocytes to exhibit high diminutive effect (>90% inhibition) at
all the three doses, LPS induced B-cell proliferation (>90% at
10ꢁ5 M conc.) was observed only for compound 12. Both the
compounds were non-cytotoxic, which is an important attribute
for an immunosuppressive agent of clinical application such as
cyclosporine A [35,36]. ConA induced T-cell proliferation effect
similar to 13 was also observed for cytotoxic compound 14 but
failed to show any effect against the other mitogen. Non-cytotoxic
compound 17 and 18 showed inhibition (maximum effect 20% at
10ꢁ5 M conc. for 17 and 26% at 10ꢁ5 M conc. and w35% at 10ꢁ6
M
conc. for 18) against ConA and LPS mitogens. For non-cytotoxic
compounds 29 and 30, inhibition at all the three dose levels was
observed against ConA and LPS induced cell proliferation, with
latter showing higher inhibitory effect. The rest of the compounds
did not show any significant activity against the mitogens. Among
8e10, 19e24 and 27, a group of di- and tri-substituted aryl triazole
derivatives, non-cytotoxic compounds 9 and 10 displayed inhibi-
tory effect against LPS and ConA induced cell proliferation.
Surprisingly, compound 8 did not show any diminutive effect and

368
P.K. Chinthakindi et al. / European Journal of Medicinal Chemistry 60 (2013) 365e375
Table 1
Effect at three different concentrations (1ꢀ10ꢁ4, 1ꢀ10ꢁ5 and 1ꢀ10ꢁ6 M) of compounds 1e31 on ConA and LPS induced murine lymphocyte proliferation (10
mg/mL).
Entry
Conc.(M)
Cytotoxicity
ConA Mean þ SE
ConA-induced T cell
proliferation rate (%)
LPS mean þ SE
LPS-induced B cell
proliferation rate (%)
1
10ꢁ4
10ꢁ5
10ꢁ6
10ꢁ4
10ꢁ5
10ꢁ6
10ꢁ4
10ꢁ5
10ꢁ6
10ꢁ4
10ꢁ5
10ꢁ6
10ꢁ4
10ꢁ5
10ꢁ6
10ꢁ4
10ꢁ5
10ꢁ6
10ꢁ4
10ꢁ5
10ꢁ6
10ꢁ4
10ꢁ5
10ꢁ6
10ꢁ4
10ꢁ5
10ꢁ6
10ꢁ4
10ꢁ5
10ꢁ6
10ꢁ4
10ꢁ5
10ꢁ6
10ꢁ4
10ꢁ5
10ꢁ6
10ꢁ4
10ꢁ5
10ꢁ6
10ꢁ4
10ꢁ5
10ꢁ6
10ꢁ4
10ꢁ5
10ꢁ6
10ꢁ4
10ꢁ5
10ꢁ6
10ꢁ4
10ꢁ5
10ꢁ6
10ꢁ4
10ꢁ5
10ꢁ6
10ꢁ4
10ꢁ5
10ꢁ6
10ꢁ4
10ꢁ5
10ꢁ6
10ꢁ4
10ꢁ5
10ꢁ6
10ꢁ4
10ꢁ5
10ꢁ6
10ꢁ4
10ꢁ5
10ꢁ6
10ꢁ4
10ꢁ5
10ꢁ6
10ꢁ4
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
þ
þ
þ
ꢁ
þ
ꢁ
ꢁ
ꢁ
ꢁ
þ
þ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
þ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
D
þ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
þ
ꢁ
þ
ꢁ
ꢁ
ꢁ
þ
þ
þ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
þ
þ
þ
ꢁ
0.77 ꢂ 0.05
0.85 ꢂ 0.10
0.49 ꢂ 0.04
1.21 ꢂ 0.12
1.04 ꢂ 0.10
0.97 ꢂ 0.16
1.48 ꢂ 0.10
0.62 ꢂ 0.07
0.65 ꢂ 0.02
0.72 ꢂ 0.01
0.81 ꢂ 0.01
1.02 ꢂ 0.07
1.38 ꢂ 0.12
0.70 ꢂ 0.09
0.55 ꢂ 0.02
0.93 ꢂ 0.10
0.84 ꢂ 0.06
0.92 ꢂ 0.03
1.08 ꢂ 0.04
1.47 ꢂ 0.02
1.13 ꢂ 0.06
1.56 ꢂ 0.17
0.95 ꢂ 0.03
1.44 ꢂ 0.18
0.67 ꢂ 0.08
0.52 ꢂ 0.02
0.67 ꢂ 0.04
0.79 ꢂ 0.03
0.81 ꢂ 0.04
0.76 ꢂ 0.06
0.84 ꢂ 0.06
1.34 ꢂ 0.14
1.11 ꢂ 0.10
0.05 ꢂ 0.01
0.05 ꢂ 0.01
0.05 ꢂ 0.01
0.04 ꢂ 0.01
0.04 ꢂ 0.01
0.04 ꢂ 0.01
0.04 ꢂ 0.02
0.05 ꢂ 0.01
0.05 ꢂ 0.03
1.19 ꢂ 0.09
1.01 ꢂ 0.06
0.79 ꢂ 0.20
1.22 ꢂ 0.34
0.84 ꢂ 0.07
0.81 ꢂ 0.05
0.92 ꢂ 0.18
0.76 ꢂ 0.08
0.80 ꢂ 0.15
0.73 ꢂ 0.13
0.70 ꢂ 0.05
0.82 ꢂ 0.16
1.43 ꢂ 0.07
1.33 ꢂ 0.06
0.99 ꢂ 0.09
0.89 ꢂ 0.01
0.48 ꢂ 0.08
0.55 ꢂ 0.21
0.59 ꢂ 0.23
0.56 ꢂ 0.18
0.85 ꢂ 0.06
0.75 ꢂ 0.29
0.51 ꢂ 0.19
0.65 ꢂ 0.21
0.74 ꢂ 0.28
0.75 ꢂ 0.25
0.74 ꢂ 0.28
0.38 ꢂ 0.12
0.44 ꢂ 0.13
0.60 ꢂ 0.10
0.54 ꢂ 0.20
ꢁ6.09
0.74 ꢂ 0.01
0.78 ꢂ 0.03
0.90 ꢂ 0.05
0.56 ꢂ 0.05
0.87 ꢂ 0.01
0.89 ꢂ 0.01
1.39 ꢂ 0.94
0.89 ꢂ 0.01
0.90 ꢂ 0.05
0.74 ꢂ 0.11
0.91 ꢂ 0.04
0.82 ꢂ 0.09
0.71 ꢂ 0.16
0.76 ꢂ 0.32
0.91 ꢂ 0.15
1.15 ꢂ 0.12
0.90 ꢂ 0.28
1.26 ꢂ 0.45
1.31 ꢂ 0.03
1.11 ꢂ 0.04
0.97 ꢂ 0.01
1.32 ꢂ 0.18
1.16 ꢂ 0.16
1.35 ꢂ 0.08
0.64 ꢂ 0.04
0.47 ꢂ 0.03
0.81 ꢂ 0.08
0.81 ꢂ 0.08
0.70 ꢂ 0.13
0.79 ꢂ 0.03
1.35 ꢂ 0.18
1.13 ꢂ 0.35
1.38 ꢂ 0.31
0.84 ꢂ 0.09
2.27 ꢂ 0.11
0.87 ꢂ 0.03
0.47 ꢂ 0.12
1.74 ꢂ 0.16
1.08 ꢂ 0.13
1.60 ꢂ 0.16
1.18 ꢂ 0.02
0.88 ꢂ 0.05
0.68 ꢂ 0.41
0.77 ꢂ 0.34
0.78 ꢂ 0.19
0.99 ꢂ 0.30
1.60 ꢂ 0.45
1.48 ꢂ 0.04
0.80 ꢂ 0.10
0.76 ꢂ 0.04
0.80 ꢂ 0.03
0.79 ꢂ 0.10
0.81 ꢂ 0.11
0.62 ꢂ 0.08
1.03 ꢂ 0.06
0.91 ꢂ 0.07
0.95 ꢂ 0.05
0.69 ꢂ 0.30
0.56 ꢂ 0.08
0.63 ꢂ 0.17
0.65 ꢂ 0.10
0.55 ꢂ 0.17
0.56 ꢂ 0.07
0.85 ꢂ 0.06
0.79 ꢂ 0.32
0.99 ꢂ 0.03
0.81 ꢂ 0.37
0.90 ꢂ 0.08
0.89 ꢂ 0.01
0.53 ꢂ 0.17
0.71 ꢂ 0.14
0.69 ꢂ 0.28
0.62 ꢂ 0.24
ꢁ36.75
ꢁ25.64
ꢁ23.07
ꢁ52.13
ꢁ25.64
ꢁ23.93
þ18.80
ꢁ23.93
ꢁ23.07
ꢁ36.75
ꢁ22.22
ꢁ29.91
þ1.42
þ3.65
ꢁ40.24
þ47.56
þ26.82
þ18.29
þ80.48
ꢁ24.39
ꢁ20.73
ꢁ12.19
ꢁ1.21
2
3
4
þ24.39
þ97.14
0.00
5
þ8.57
ꢁ21.42
þ13.41
þ2.43
þ30.00
ꢁ1.70
6
ꢁ23.07
þ7.69
þ12.19
ꢁ10.00
þ22.50
ꢁ5.83
7
ꢁ9.16
ꢁ7.50
ꢁ19.16
þ12.82
ꢁ0.85
8
þ90.24
þ15.85
þ75.60
L29.47
L45.26
L29.47
L16.84
L14.73
L20.00
þ2.43
þ15.38
L32.63
L50.52
L14.73
L14.73
L26.31
L16.84
þ15.38
ꢁ3.41
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
þ63.41
þ35.36
L93.90
L95.12
L93.90
L95.12
L95.12
L95.12
L95.12
L93.90
L93.90
þ70.00
þ44.28
þ12.85
þ48.78
þ2.43
þ17.94
ꢁ28.20
L94.01
ꢁ25.64
L36.75
þ48.71
ꢁ7.69
þ36.75
þ0.85
ꢁ24.78
ꢁ2.85
þ10.00
þ11.42
ꢁ15.38
þ36.75
þ26.49
L15.79
L20.00
L15.79
L16.84
L14.73
L34.73
ꢁ14.16
ꢁ24.16
ꢁ20.83
ꢁ11.42
ꢁ50.00
ꢁ8.57
ꢁ1.21
L3.15
L20.00
L15.79
L23.15
L26.31
L13.68
þ19.16
þ10.83
ꢁ17.50
þ27.14
ꢁ31.42
ꢁ21.42
ꢁ15.74
ꢁ20.00
þ21.42
þ7.14
ꢁ7.14
ꢁ21.42
ꢁ20.00
þ21.42
þ12.85
þ41.42
þ15.71
þ28.57
þ27.14
ꢁ24.28
þ1.42
ꢁ27.14
ꢁ7.14
þ5.71
þ7.14
þ5.71
ꢁ45.71
ꢁ37.14
ꢁ14.28
ꢁ22.85
ꢁ1.42
ꢁ11.42

P.K. Chinthakindi et al. / European Journal of Medicinal Chemistry 60 (2013) 365e375
369
Table 1 (continued )
Entry
Conc.(M)
Cytotoxicity
ConA Mean þ SE
ConA-induced T cell
proliferation rate (%)
LPS mean þ SE
LPS-induced B cell
proliferation rate (%)
10ꢁ5
10ꢁ6
10ꢁ4
10ꢁ5
10ꢁ6
10ꢁ4
10ꢁ5
10ꢁ6
10ꢁ4
10ꢁ5
10ꢁ6
10ꢁ4
10ꢁ5
10ꢁ6
10ꢁ4
10ꢁ5
10ꢁ6
10ꢁ4
10ꢁ5
10ꢁ6
ꢁ
ꢁ
þ
þ
ꢁ
ꢁ
ꢁ
þ
ꢁ
ꢁ
þ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
þ
ꢁ
þ
0.49 ꢂ 0.11
0.65 ꢂ 0.15
0.63 ꢂ 0.28
0.36 ꢂ 0.04
0.91 ꢂ 0.15
1.23 ꢂ 0.09
1.20 ꢂ 0.05
1.03 ꢂ 0.06
0.76 ꢂ 0.26
0.79 ꢂ 0.20
0.50 ꢂ 0.14
0.95 ꢂ 0.05
1.12 ꢂ 0.14
1.13 ꢂ 0.04
0.89 ꢂ 0.13
0.67 ꢂ 0.08
0.68 ꢂ 0.05
1.53 ꢂ 0.05
1.36 ꢂ 0.04
0.96 ꢂ 0.06
ꢁ30.00
ꢁ7.14
0.48 ꢂ 0.09
1.14 ꢂ 0.36
0.79 ꢂ 0.37
0.58 ꢂ 0.17
0.89 ꢂ 0.14
0.99 ꢂ 0.02
1.00 ꢂ 0.01
0.91 ꢂ 0.02
1.23 ꢂ 0.22
0.64 ꢂ 0.11
1.02 ꢂ 0.03
0.78 ꢂ 0.01
0.93 ꢂ 0.01
0.91 ꢂ 0.04
0.87 ꢂ 0.11
0.60 ꢂ 0.06
0.53 ꢂ 0.04
1.40 ꢂ 0.02
1.02 ꢂ 0.01
0.90 ꢂ 0.01
ꢁ31.42
þ62.85
þ12.85
ꢁ17.14
þ27.14
ꢁ17.50
ꢁ16.66
ꢁ24.16
þ75.71
ꢁ8.57
26
27
28
29
30
31
ꢁ10.00
ꢁ48.57
þ30.00
þ2.50
0.00
ꢁ14.16
þ8.57
þ12.85
ꢁ28.57
L20.83
L6.66
L5.83
L6.31
L29.47
L28.42
þ27.50
þ13.33
ꢁ20.00
þ45.71
L35.00
L22.50
L24.16
L8.42
L36.84
L44.21
þ16.66
ꢁ15.00
ꢁ25.00
þ Indicate immune stimulant agents while ꢁ indicate immunosuppressive agents. Results are mean standard error (SE) of three separate experiments, conducted in triplicate
at the concentrations 1ꢀ10ꢁ4, 1ꢀ10ꢁ5 and 1ꢀ10ꢁ6 M.
The bold values are shown for those compounds which have proved to be active and those in normal font represent least significant.
was cytotoxic. Cytotoxic compounds 19, 20 and 21 showed inhi-
bition against LPS induced B-cell proliferation but not against
ConA. Compounds 22e24 and 27 proved to be ineffective in
inhibiting the Con A and LPS induced cell proliferation effect. In
terms of SAR, no clear relationship could be established.
analysis (RP-18 column, Merck, with UV detector, isocratic mobile
phase acetonitrile and water (70:30) with flow rate 0.8 mL/min).
4.1.1. Isolation of
-Santonin was isolated in bulk quantity from the aerial part of A.
laciniata (duly authenticated by the taxonomist of our institute).
a-santonin
a
a-
Santonin used in present study was of 98% purity (HPLC analysis)
achieved through repeated column chromatography over silica gel
60e120 mesh and the natural product was well characterized by
spectroscopicstudy(foundinagreementwiththeliteraturedata)[32].
3. Conclusion
We have demonstrated the inhibitory activity of a novel library
of 1,2,3-triazole desmotroposantonin derivatives created through
AzideeAlkyne Huisgen 1,3-dipolar cycloaddition reaction and
characterized by spectral analysis against ConA induced T-cell and
LPS induced B-cell proliferation. Six (9, 10, 17, 18, 29, and 30) out of
a library of 31 compounds have been identified as potent immu-
nosuppressant agents showing inhibition against induced T-cell
and B-cell proliferation and the bioactives found without any
cytotoxic effect. Further, selective diminutive effect against ConA
induced T-cell proliferation for compounds 12 and 13 have also
been demonstrated.
4.1.2. Preparation of
The title compound was prepared by the Thiele acetylation
(dienone-phenol rearrangement) method [32], by treating -santonin
a-desmotroposantonin acetate (2)
a
(1.0 g, 4 mmol) the acetic anhydride (5 mL) and sulphuric acid (0.5 mL,
9.3 mmol) at 0e10 ꢃC temperature for 1 h. On usual workup, the
acetylated product 2 (1.04 g, 89% yield) was obtained as a solid, mp
139.5e139.9 ꢃC. 1H NMR (200 MHz, CDCl3):
d 6.83 (1H, s, AreH), 5.58
(1H, d, J ¼ 6.0 Hz, AreCHOe), 2.73e2.77 (1H, m, eCHCHCH3), 2.54e
2.56 (2H, m, AreCH2e), 2.42e2.44 (1H, m, eCHCHCH3), 2.33 (3H, s,
eOCOCH3), 2.22 and 2.21 (3H each, s, 2ꢀ AreCH3), 1.93e1.73 (2H, m,
ArCH2CH2e), 1.39 (3H, d, J ¼ 7.2 Hz, eCHCH3). 13C NMR (100 MHz,
4. Experimental
CDCl3): d 179.45, 169.62, 147.41, 134.82, 134.09, 131.27, 129.01, 123.84,
4.1. Chemistry
75.47, 41.60, 40.43, 24.01, 23.36, 20.78, 19.53, 14.45, 12.09. IR gmax
(neat):2925,1766,1465,1213, 987, 950, 908, 696, 669 cmꢁ1. HRMS m/z
calcd for C17H20O4 [M þ H]þ 289.14343, found. 289.14271.
All reagents for chemical synthesis were obtained from Sigma
Aldrich and the solvents used in reactions were distilled and dried
prior to use. All the chemical reactions were monitored by TLC on
0.25 mm silica gel 60 F254 plates (E. Merck) using 2% ceric ammo-
nium sulphate solution for detection of the spots. Purification of
compounds was carried out by column chromatography using
Silica gel 60e120 mesh stationary phase. 1H NMR and 13C NMR
4.1.3. Preparation of
The title compound was prepared in (0.785 g, 92% yield) by
deacetylation of -desmotroposantonin acetate (2) (1.0 g) using
a-desmotroposantonin (3)
a
methanol/ammonium hydroxide (1:1) mixture (50 mL) with slight
modification of the reported method [37], mp 197e199 ꢃC, lit. mp
spectra (with chemical shifts expressed in
d
and coupling constants
198 ꢃC. 1H NMR (200 MHz, CD3OD):
d 6.65 (1H, s, AreH), 5.71 (1H, d,
in Hertz) were recorded on Bruker DPX 200, 400 and DPX 500
instruments using CDCl3 or CD3OD as the solvents with TMS as
internal standard. High resolution mass spectra (HRMS) were
recorded on Agilent Technologies 6540 instrument and IR recorded
on an FT-IR Bruker (270-30) spectrophotometer. Melting points of
compounds were recorded on Buchi melting point apparatus B-
542. HPLC was run on Agilent Technologies 1200 series instrument.
All the compounds (1e31) were >95% purity as confirmed by HPLC
J ¼ 6.08 Hz, AreCHOe), 2.61e2.70 (1H, m, eCHCHCH3), 2.50e2.54
(2H, m, AreCH2e), 2.37e2.46 (1H, m, eCHCHCH3), 2.21 and 2.15
(3H each, s, 2ꢀ AreCH3), 1.89 and 1.61 (1H each, m, ArCH2CH2e),
1.35 (3H, d, J ¼ 7.29, eCHCH3). 13C NMR (100 MHz, CD3OD):
d
181.0, 153.02, 134.30, 130.61, 127.37, 123.22, 117.74, 76.71, 41.99,
40.87, 23.83, 23.68, 19.5, 14.47, 11.48. IR gmax (neat): 3426, 2925,
1761, 1464, 1171, 867, 814, 716, 688, 624 cmꢁ1. HRMS m/z calcd for
C
15H18O3 [M þ H]þ 247.13287, found 247.13195.

370
P.K. Chinthakindi et al. / European Journal of Medicinal Chemistry 60 (2013) 365e375
4.1.4. Preparation of O-propargyl-
a-desmotroposantonin (4)
127.49, 127.0, 126.12, 120.79, 118.97, 118.57, 115.07, 75.75, 62.97,
The compound prepared by the propargylation of compound 3
(1.0 g, 4 mmol), using the propargyl bromide (0.68 mL, 6 mmol) and
K2CO3 (0.5 g, 8 mmol) in acetone (50 mL) under reflux for 6 h to give
after usual work the propargylated product 4 (1.10 g, 96% yield) [33]
41.84, 40.48, 23.70, 23.65, 20.0, 14.51, 11.79. IR gmax (neat): 3400,
2926, 2853, 2107, 1767, 1633, 1602, 1515, 1444, 1381, 1297, 1222,
1164, 1124, 1044, 987, 950, 857, 814, 771, 669 cmꢁ1. HRMS m/z calcd
for C28H27N3O3 [M þ H]þ 454.21251, found 454.21143.
as a solid, mp 105e108 ꢃC. 1H NMR (200 MHz, CDCl3):
d 6.85 (1H, s,
AreH), 5.61 (1H, d, J ¼ 6.2 Hz, AreCHOe), 4.68 (2H, s, eOCH2e),
2.64e2.72 (1H, m, eCHCHCH3), 2.39e2.58 (4H, m, AreCH2e, e
CHCHCH3, eOCH2CHe), 2.29 and 2.25 (3H each, s, 2ꢀ AreCH3),
1.81e1.93 and 1.68e1.80 (1H each, m, ArCH2CH2e), 1.39 (3H, d,
4.1.5.3. Synthesis of 3-hydroxy-1-{(5-
yl-1H-1,2,3-triazolyl}-benzene (7). The title compound prepared by
the reaction of propargylated -desmotroposantonin (114 mg,
0.40 mmol) and 3-hydroxy phenyl boronic acid (66 mg, 0.48 mmol)
as per method described in Section 4.1.5 to give 7 (111 mg, 98%
yield). Yellow solid; mp: 192e195 ꢃC. 1H NMR (400 MHz, CDCl3):
a-desmotroposantonin) meth
a
J ¼ 7.3 Hz, CH3eCHe). 13C NMR (100 MHz, CDCl3):
d 179.58, 153.89,
134.10, 131.04, 129.10, 126.57, 115.37, 79.02, 75.70, 75.23, 56.60,
41.82, 40.52, 23.74, 23.64, 19.98, 14.51, 11.67. IR gmax (neat): 3528,
3279, 2929, 2359, 2119, 1765, 1597, 1479, 1378, 1295, 1223, 1165,
1115, 1051, 986 cmꢁ1. HRMS m/z calcd for C18H21O3 [M þ H]þ
285.14852, found 285.14772.
d
8.87 (1H, s, eNCHe), 7.31e7.40 (3H, m, Ar1eH), 7.10 (1H, s, AreH),
6.88 (1H, d, J ¼ 8.0 Hz, Ar1eH), 5.69 (1H, d, J ¼ 6.0 Hz, AreCHOe),
5.19 (2H, s, eOCH2e), 2.66e2.71 (1H, m, eCHCHCH3), 2.42e2.53
(3H, m, AreCH2e, eCHCHCH3), 2.44 and 2.22 (3H each, s, 2ꢀ Are
CH3), 1.83e1.88 and 1.51e1.55 (1H each, m, AreCH2CH2e), 1.29
4.1.5. General experimental procedure for preparation 1,2,3-
(3H, d, J ¼ 7.21 Hz, CH3CHe). 13C NMR (100 MHz, CDCl3):
d 180.19,
triazoles of
a-desmotroposantonin (5e31)
158.73, 154.26, 144.69, 137.84, 134.50, 131.32, 131.26, 129.32, 125.28,
122.81, 116.28, 115.46, 111.05, 107.44, 75.82, 62.04, 41.09, 40.57,
23.51, 23.48, 19.82, 14.43, 11.76. IR gmax (neat): 2928, 1763, 1598,
1473,1228,1167, 1116, 992, 864, 835, 734, 694 cmꢁ1 HRMS m/z calcd
for C24H25N3O4 [M þ H]þ 420.19178, found 420.1912.
NaN3 (1.2 equiv), CuSO4 (0.1 equiv), and boronic acids (1.2 equiv)
in methanol (10 mL) were allowed to react for 1e4 h, followed by
addition of water (10 mL), sodium ascorbate (0.5 equiv), and
propargylated a-desmotroposantonin (1.0 equiv) [34]. The contents
were stirred vigorously at room temperature for 2e8 h (as moni-
tored by TLC analysis). After completion of the reaction, the
contents diluted with water and extracted with ethyl acetate (3
times). The combined ethyl acetate extract was washed with brine,
dried over anhydrous Na2SO4 and evaporated under reduced
pressure on a rota vapour. The crude product obtained thus sub-
jected was put to column chromatography (silica gel) with EtOA-
c:Hexane (15:85) mixture as eluent to afford the desired pure
products in >97% yields.
4.1.5.4. Synthesis of 3,4-dimethoxy-1{(5-
methyl-1H-1,2,3-triazolyl}-benzene (8). The title compound
prepared by the reaction of propargylated -desmotroposantonin
(71 mg, 0.25mmol)and3,4-dimethoxy phenyl boronicacid (54.6mg,
0.30 mmol) as per method described in Section 4.1.5 to give 8
(112 mg, 97% yield). Yellow solid; mp: 144e146 ꢃC. 1H NMR
a-desmotroposantonin)
a
(500 MHz, CDCl3):
d
7.91 (1H, s, eNCHe), 7.29 (1H, d, J ¼ 2.38 Hz, Ar1e
H), 7.10 (1H, dd, J ¼ 8.61 and 2.44 Hz, Ar1eH), 6.87 (1H, d, J ¼ 8.62 Hz,
Ar1eH), 6.83 (1H, s, AreH), 5.54 (1H, d, J ¼ 6.27 Hz, AreCHOe), 5.20
(2H, s, eOCH2e), 3.88 and 3.86 (3H each, s, 2ꢀ eOCH3), 2.62e2.66
(1H, m, eCHCHCH3), 2.34e2.48 (3H, m, AreCH2e, eCHCHCH3),
2.23 and 2.16 (3H each, s, 2ꢀ AreCH3), 1.78e1.88 and 1.60e1.69
4.1.5.1. Synthesis of {(5-
triazolyl}-benzene (5). The title compound prepared by the reac-
tion of propargylated -desmotroposantonin (100 mg, 0.35 mmol)
a-desmotroposantonin)methyl-1H-1,2,3-
a
and phenyl boronic acid (51.2 mg, 0.42 mmol) as per the method
(1H each, m, AreCH2CH2e), 1.31 (3H, d, J ¼ 7.16 Hz, CH3CHe). 13
C
described in Section 4.1.5 to give 5 (137 mg, 97% yield), brown solid;
NMR (100 MHz): d 179.59, 154.48, 149.80, 149.49, 145.31, 134.35,
mp: 182e183 ꢃC. 1H NMR (200 MHz, CDCl3):
d
8.03 (1H, s, eNCHe),
131.02, 130.61, 128.76, 126.09, 120.92, 115.10, 112.59, 111.22, 105.09,
75.74, 62.95, 56.27, 56.21, 41.82, 40.49, 23.70, 23.64,19.98,14.51,11.74.
IR gmax (neat): 3399, 2929, 1764, 1602, 1519, 1459, 1382, 1298, 1262,
1238,1164,1123,1045,1024, 949, 849, 769, 668 cmꢁ1. HRMS m/z calcd
for C26H29N3O5 [M þ H]þ 464.21799, found 464.21746.
7.76 (2H, d, J ¼ 7.17 Hz, Ar1eH), 7.45e7.58 (3H, m, Ar1eH), 6.91 (1H,
s, AreH), 5.63 (1H, d, J ¼ 6.29 Hz, AreCHOe), 5.30 (2H, s, eOCH2e),
2.68e2.78 (1H, m, eCHCHCH3), 2.58e2.68 (3H, m, AreCH2e, e
CHCHCH3), 2.32 and 2.25 (3H each, s, 2ꢀ AreCH3), 1.75e1.91 and
1.58e1.66 (1H each, m, AreCH2CH2e), 1.39 (3H, d, J ¼ 7.28 Hz,
CH3CHe). 13C NMR (100 MHz, CDCl3):
d
179.58, 154.46, 145.82,
4.1.5.5. Synthesis of 3,4-methylenedioxy-1-{(5-
tonin)methyl-1H-1,2,3-triazolyl}-benzene (9). The title compound
prepared by the reaction of propargylated -desmotroposantonin
a-desmotroposan-
137.03, 134.35, 131.05, 129.79 (3CH), 128.86 (2CH), 128.80, 126.11,
120.63, 115.10, 75.74, 62.91, 41.82, 40.48, 23.69, 23.64, 19.97, 14.50,
11.73. IR gmax (neat): 3720, 2921, 1596, 1499, 1301, 1228, 1168, 1045,
947, 851, 766, 681, 489, 450 cmꢁ1. HRMS m/z calcd for C24H25N3O3
[M þ H]þ 404.19686, found 404.19786.
a
(113.7 mg, 0.40 mmol) and 3,4-methylenedioxy phenyl boronic acid
(80 mg, 0.48 mmol) as per method described in Section 4.1.5 to give
9 (173 mg, 97% yield). Brown solid; mp: 215e235 ꢃC. 1H NMR
(200 MHz, CDCl3):
d
7.85 (1H, s, NCHe), 7.06 (1H, dd, J ¼ 8.31 and
4.1.5.2. Synthesis of 2-{(5-
triazolyl}-naphthalene (6). The title compound prepared by the
reaction of propargylated -desmotroposantonin (85 mg,
a
-desmotroposantonin)methyl-1H-1,2,3-
2.16 Hz, Ar1eH), 6.83 (1H, s, AreH), 6.81 (1H, d, J ¼ 8.16 Hz, Ar1eH),
6.01 (2H, s, eOCH2Oe), 5.55 (1H, d, J ¼ 6.23 Hz, AreCHOe), 5.20
(2H, s, eOCH2e), 2.64e2.68 (1H, m, eCHCHCH3), 2.37e2.51 (3H, m,
AreCH2e, eCHCHCH3), 2.24 and 2.18 (3H each, s, 2ꢀ AreCH3),
1.85e1.95 and 1.62.1.71 (1H each, m, ArCH2CH2e), 1.31 (3H, d,
a
0.30 mmol) and naphthalen-2-yl-2-boronic acid (62 mg,
0.36 mmol) as per method described in Section 4.1.5 to give 6
(130 mg, 96% yield). Yellow gummy mass; 1H NMR (200 MHz,
J ¼ 7.35 Hz, CH3CHe). 13C NMR (125 MHz):
d 179.66, 154.31, 148.65,
CDCl3):
d
8.17 (2H, d, J ¼ 6.65 Hz, Ar1eH), 7.90e8.10 (4H, m, 3ꢀ Ar1e
148.11, 145.33, 134.37, 131.49, 131.02, 128.77, 126.08, 120.96, 115.03,
114.37, 108.53, 102.87, 102.14, 75.76, 62.91, 41.83, 40.48, 23.70,
23.63, 20.10, 14.52, 11.76. IR gmax (neat): 3300, 2922, 1763, 1600,
1462,1381,1122,1039, 944, 879, 830, 745, 698, 647, 512 cmꢁ1. HRMS
m/z calcd for C25H25N3O5 [M þ H]þ 448.18669, found 448.18682.
H and eNCHe), 7.56e7.60 (2H, dd, J ¼ 8.77 and 4.08 Hz, Ar1eH),
6.92 (1H, s, AreH), 5.63 (1H, d, J ¼ 6.14 Hz, AreCHOe), 5.33 (2H,
s, eOCH2e), 2.63e2.71 (1H, m, eCHCHCH3), 2.53e1.59 (3H, m, Are
CH2e, eCHCHCH3), 2.31 and 2.25 (3H each, s, 2ꢀ AreCH3), 1.75e
1.90 and 1.57e1.69 (1H each, m, AreCH2CH2e), 1.39 (3H, d,
J ¼ 7.32 Hz, CH3CHe). 13C NMR (125 MHz):
d
179.60, 154.47, 145.64,
4.1.5.6. Synthesis of 3,4,5-trimethoxy-1-(5-a-desmotroposantonin)
134.37, 133.22, 132.94, 131.05, 130.06, 130.04, 128.78, 128.31, 127.95,
methyl-1H-1,2,3-triazolyl}-benzene (10). The title compound

P.K. Chinthakindi et al. / European Journal of Medicinal Chemistry 60 (2013) 365e375
371
prepared by the reaction of propargylated
a
-desmotroposantonin
Ar1eH), 7.21 (1H, d, J ¼ 14.75 Hz, eNCH]CHe), 6.87 (1H, s, AreH),
5.62 (1H, d, J ¼ 6.14 Hz, AreCHOe), 5.26 (2H, s, eOCH2e), 2.70e2.74
(1H, m, eCHCHCH3), 2.45e2.59 (3H, m, AreCH2e, eCHCHCH3), 2.32
and 2.24 (3H each, s, 2ꢀ AreCH3), 1.79e1.89 and 1.65e1.74 (1H
each, m, AreCH2CH2e), 1.39 (3H, d, J ¼ 7.31 Hz, CH3CHe). 13C NMR
(57 mg, 0.20 mmol) and 3,4,5-trimethoxy phenyl boronic acid
(51 mg, 0.24 mmol) as per method described in Section 4.1.5 to give
10 (96 mg, 97% yield). Brown solid; mp: 207 ꢃC. 1H NMR (400 MHz,
CDCl3): d
8.00 (1H, s, NCHe), 6.96 (2H, s, Ar1eH), 6.91 (1H, s, AreH),
5.63 (1H, d, J ¼ 6.14 Hz, AreCHOe), 5.28 (2H, s, eOCH2e), 3.94 (6H,
s, 2ꢀ eOCH3), 3.89 (3H, s, eOCH3), 2.66e2.70 (1H, m, eCHCHCH3),
2.39e2.53 (3H, m, AreCH2e, eCHCHCH3), 2.32 and 2.25 (3H each, s,
2ꢀ AreCH3), 1.84e193 and 1.71e1.80 (1H each, m, ArCH2CH2e),
1.39 (3H, d, J ¼ 7.31 Hz, CH3CHe). 13C NMR (100 MHz, CDCl3):
(100 MHz, CDCl3): d 179.65, 154.36, 145.24, 134.35, 133.49, 131.04,
129.03 (2CH), 128.86, 128.77, 126.77 (2CH), 126.05, 122.91, 122.11,
119.87, 114.95, 75.76, 62.79, 41.83, 40.48, 23.69, 23.64, 19.98, 14.51,
11.74. IR gmax (neat): 3391, 2918, 2850, 1765, 1657, 1599, 1481, 1455,
1351, 1297, 1223, 1203, 1165, 1124, 1045, 986, 949, 903, 846, 752,
693, 666, 582, 548, 526, 520, 513, 507 cmꢁ1. HRMS m/z calcd for
d
179.58, 154.48, 153.92 (2C), 145.35, 138.44, 134.34, 132.85, 131.02,
128.80,126.03, 121.12,115.09, 98.63 (2CH), 75.73, 62.86, 61.01, 56.49
C
26H27N3O3 [M þ H]þ 430.21251, found 430.21208.
(2CH3), 41.79, 40.51, 23.69, 22.6, 19.95, 14.49, 11.71. IR gmax (neat):
3404, 2919, 1763, 1603, 1462, 1127, 827, 722, 699, 646, 521 cmꢁ1
.
4.1.5.10. Synthesis of 3-nitro-1-{(5-
1H-1,2,3-triazolyl}-benzene (14). The title compound prepared by
the reaction of propargylated -desmotroposantonin (114 mg,
a-desmotroposantonin)methyl-
HRMS m/z calcd for C27H31N3O6 [M þ H]þ 494.22856, 494.22772.
a
4.1.5.7. Synthesis of 4-pheny-1-{(5-
1H-1,2,3-triazolyl}-benzene (11). The title compound prepared by
the reaction of propargylated -desmotroposantonin (100 mg,
a
-desmotroposantonin)methyl-
0.40 mmol) and 3-nitro phenyl boronic acid (80 mg, 0.48 mmol) as
per method described in Section 4.1.5 to give 14 (170 mg, 95% yield).
a
Yellow solid; mp: 199e201 ꢃC. 1H NMR (200 MHz, CDCl3):
d 8.64
0.35 mmol) and biphenyl boronic acid (83 mg, 0.42 mmol) as per
(1H, d, J ¼ 1.83 Hz, Ar1eH), 8.32 (1H, d, J ¼ 8.06 Hz, Ar1eH), 8.19 (1H,
d, J ¼ 8.18 Hz, Ar1eH), 8.16 (1H, s, eNCHe), 7.76 (1H, dd, J ¼ 8.20 and
8.19 Hz, Ar1eH), 6.19 (1H, s, AreH), 5.63 (1H, d, J ¼ 6.19 Hz, Are
CHOe), 5.33 (2H, s, eOCH2e), 2.67e2.71 (1H, m, eCHCHCH3),
2.45e2.59 (3H, m, AreCH2e, eCHCHCH3), 2.35 and 2.25 (3H each, s,
2ꢀ AreCH3), 1.81e1.91 and 1.62e1.71 (1H each, m, AreCH2CH2e),
1.39 (3H, d, J ¼ 7.31 Hz, CH3CHe). 13C NMR (125 MHz, CDCl3):
method described in Section 4.1.5 to give 11 (162 mg, 97% yield).
Yellow solid; mp: 186e188 ꢃC. 1H NMR (400 MHz, CDCl3):
d 8.0 (1H,
s, eNCHe), 7.75 (2H, d, J ¼ 8.80 Hz, 2ꢀ Ar1eH), 7.67 (2H, dd, J ¼ 8.40
and 1.60 Hz, 2ꢀ Ar1eH), 7.55 (2H, dd, J ¼ 8.40 and 1.20 Hz, 2ꢀ Ar2e
H), 7.37 (3H, m, 3ꢀ Ar2eH), 6.84 (1H, s, AreH), 5.55 (1H, d,
J ¼ 6.40 Hz, AreCHOe), 5.23 (2H, s, eOCH2e), 2.63e2.67 (1H, m, e
CHCHCH3), 2.41e2.55 (3H, m, AreCH2e, eCHCHCH3), 2.46 and 2.25
(3H each, s, 2ꢀ AreCH3), 1.80e1.90 and 1.60e1.69 (1H each, m, Are
CH2CH2e), 1.32 (3H, d, J ¼ 7.41 Hz, CH3CHe). 13C NMR (100 MHz
d
179.64, 154.22, 148.91, 146.31, 137.66, 134.42, 131.08, 131.02,
128.97, 126.07, 125.99, 123.28, 120.60, 115.40, 114.94, 75.70, 62.69,
41.77, 40.48, 23.69, 23.60, 20.02, 14.51, 11.75. IR gmax (neat): 3435,
2925, 1764, 1597, 1535, 1482, 1382, 1350, 1298, 1222, 1165, 1125,
1045, 986, 950, 903, 871, 804, 759, 738, 667 cmꢁ1. HRMS m/z calcd
for C24H24N4O5 [M þ H]þ 449.18194, found 449.18095.
CDCl3):
d 179.63, 154.44, 141.87, 139.59, 139.26 (2C), 134.37, 131.04,
128.99 (2CH), 128.79, 128.38 (2CH), 127.98, 127.08 (2CH), 126.12,
120.91 (3CH), 115.09, 75.77, 62.91, 41.84, 40.49, 23.70, 23.64, 19.99,
14.50, 11.76. IR gmax (neat): 3391, 2926, 2853, 1766, 1599, 1525,
1488,1458,1407,1381,1351,1318,1298,1223,1203,1165,1124,1088,
1046, 949, 932, 904, 842, 720, 698, 666, 555, 508 cmꢁ1. HRMS m/z
calcd for C30H29N3O3 [M þ H]þ 480.22816, found 480.22678.
4.1.5.11. Synthesis of 4-fluoro-1{(5-
1H-1,2,3-triazolyl}-benzene (15). The title compound prepared by
the reaction of propargylated -desmotroposantonin (100 mg,
a-desmotroposantonin)methyl-
a
0.35 mmol) and 4-fluoro phenyl boronic acid (59 mg, 0.42 mmol) as
per method described in Section 4.1.5 to give 15 (144 mg, 98%
yield). Yellow solid; mp: 186e190 ꢃC. 1H NMR (200 MHz, CDCl3):
4.1.5.8. Synthesis of 6-methoxy-2-{(5-
yl-1H-1,2,3-triazolyl}-naphthalene (12). The title compound
prepared by the reaction of propargylated -desmotroposantonin
a-desmotroposantonin)meth
a
d
7.98 (1H, s, eNCHe), 7.73 (2H, d, J ¼ 8.78 Hz, Ar1eH), 7.24 (2H, d,
(71 mg, 0.25 mmol) and 6-methoxy naphthalen-2-yl-2-boronic acid
(61 mg, 0.30mmol) as per method described in Section 4.1.5to give 12
(117 mg, 97% yield). Yellow solid; mp: 230 ꢃC. 1H NMR (200 MHz,
J ¼ 8.74 Hz, Ar1eH), 6.90 (1H, s, AreH), 5.62 (1H, d, J ¼ 6.13 Hz, Are
CHOe), 5.29 (2H, s, eOCH2e), 2.64e2.68 (1H, m, eCHCHCH3),
2.45e2.59 (3H, m, AreCH2e, eCHCHCH3), 2.31 and 2.25 (3H each, s,
2ꢀ AreCH3), 1.81e1.91 and 1.63e1.72 (1H each, m, AreCH2CH2e),
CDCl3):
d
8.11 (2H, s and d merged, J ¼ 8.32 Hz, Ar1eH), 7.90 (1H, s, e
NCHe), 7.84 (2H, s and d merged, J ¼ 8.36 Hz, Ar1eH), 7.22 (2H,
d merged, J ¼ 8.32 Hz, Ar1eH), 6.91 (1H, s, AreH), 5.59 (1H, d,
J ¼ 5.77 Hz, AreCHOe), 5.31 (2H, s, eOCH2e), 3.94 (3H, s, OCH3),
2.60e2.64 (1H, m, eCHCHCH3), 2.35e2.49 (3H, m, AreCH2e, e
CHCHCH3), 2.32 and 2.23 (3H each, s, 2ꢀ AreCH3), 1.83e1.93 and
1.65e1.75 (1H each, m, AreCH2CH2e),1.38 (3H, d, J ¼ 7.23 Hz, CH3CHe
1.38 (3H, d, J ¼ 7.27 Hz, CH3CHe). 13C NMR (125 MHz):
d 179.67,
162.12 (3JCF ¼ 251.69 Hz), 154.35, 145.21, 134.39, 131.03, 128.82,
126.06, 122.68, 122.65 (3JCF
¼
8.68 Hz), 120.82, 116.76
(2JCF ¼ 23.27 Hz), 115.0, 75.75, 62.86, 41.79, 40.46, 23.67, 23.60,
20.01, 14.51, 11.76. IR gmax (neat): 3456, 2919, 1763, 1515, 1461, 1174,
1110, 846, 788, 702, 627, 550, 479 cmꢁ1. HRMS m/z calcd for
). 13C NMR (100 MHz CDCl3):
d
179.70, 158.54, 154.44, 145.44, 134.34,
C
24H24FN3O3 [M þ H]þ 422.18744, found 422.18657.
134.32, 132.61, 130.97, 129.70, 128.75, 128.56, 128.48, 126.08, 120.82,
120.44, 119.50, 118.66, 115.07, 105.83, 75.86, 75.28, 62.52, 55.23, 41.12,
40.29, 23.67, 23.62,14.47,11.74. IR gmax (neat): 3400, 2917, 2849,1764,
1608, 1514, 1462, 1419, 1383, 1298, 1265, 1222, 1164, 1123, 1047, 1027,
985, 949, 932, 909, 853, 817, 706, 666, 540, 506 cmꢁ1. HRMS m/z calcd
for C29H29N3O4 [M þ H]þ 484.22254, found 484.22192.
4.1.5.12. Synthesis of 4-bromo-1-{(5-
1H-1,2,3-triazolyl}-benzene (16). The title compound prepared by
the reaction of propargylated -desmotroposantonin (71 mg,
0.25 mmol) and 4-bromo phenyl boronic acid (60 mg, 0.30 mmol)
as per method described in Section 4.1.5 to give 16 (116 mg, 97%
yield). Yellow solid; mp: 217e218 ꢃC. 1H NMR (400 MHz, CDCl3):
a-desmotroposantonin)methyl-
a
4.1.5.9. Synthesis of
triazolyl}-styrene (13). The title compound prepared by the reac-
tion of propargylated -desmotroposantonin (85 mg, 0.30 mmol)
b
-{(5-
a
-desmotroposantonin)methyl-1H-1,2,3-
d
8.01 (1H, s, eNCHe), 7.62e7.67 (4H, m, 4ꢀ Ar1eH), 6.88 (1H, s,
AreH), 5.62 (1H, s, J ¼ 6.01 Hz, AreCHOe), 5.28 (2H, s, eOCH2e),
2.67e2.71 (1H, m, eCHCHCH3), 2.42e2.56 (3H, m, AreCH2e, e
CHCHCH3), 2.30 and 2.23 (3H each, s, 2ꢀ AreCH3), 1.82e1.92 and
1.67e1.76 (1H each, m, AreCH2CH2e), 1.39 (3H, d, J ¼ 7.27 Hz,
a
and (E)-2-phenyl vinyl boronic acid (53 mg, 0.36 mmol) as per
method described in Section 4.1.5 to give 13 (123 mg, 96% yield).
Yellow solid; mp: 168 ꢃC. 1H NMR (200 MHz, CDCl3):
d
7.92 (1H, s, e
CH3CHe). 13C NMR (100 MHz, CDCl3):
d 179.67, 154.37, 145.83,
NCHe), 7.76 (1H, d, J ¼ 14.73 Hz, eNCH]CHe), 7.34e7.5 (5H, m,
137.03, 134.41, 132.97 (2CH), 131.40, 131.08, 128.89, 126.12, 122.04

372
P.K. Chinthakindi et al. / European Journal of Medicinal Chemistry 60 (2013) 365e375
(2CH), 120.53, 115.08, 75.78, 62.86, 41.83, 40.48, 23.69, 23.63, 19.98,
14.51, 11.75. IR gmax (neat): 3368, 2925, 2124, 1759, 1586, 1558, 1497,
1427, 1392, 1369, 1349, 1305, 1230, 1175, 1124, 1102, 1079, 1063,
1010, 987, 949, 825, 769, 735, 681, 627, 547, 517 cmꢁ1. HRMS m/z
calcd for C24H24BrN3O3 [M þ H]þ 482.10738, found 482.10591.
4.1.5.16. Synthesis
troposantonin)methyl-1H-1,2,3-triazolyl}-benzene (20). The title
compound prepared by the reaction of propargylated -des-
of
6-bromo-2-fluoro-3-iodo-1-{(5-a-desmo-
a
motroposantonin (129 mg, 0.45 mmol) and 6-bromo-2-fluoro-
3-iodo phenyl boronic acid (186 mg, 0.54 mmol) as per method
described in Section 4.1.5 to give 20 (272 mg, 97% yield).
4.1.5.13. Synthesis of 3-iodo-1-{(5-
1H-1,2,3-triazolyl}-benzene (17). The title compound prepared by
the reaction of propargylated -desmotroposantonin (58 mg,
a-desmotroposantonin)methyl-
Yellow gummy mass. 1H NMR (200 MHz, CDCl3):
d 7.82 (1H, d,
J ¼ 8.58, Ar1eH), 7.79 (1H, s, eNCHe), 7.34 (1H, d, J ¼ 8.6 Hz,
Ar1eH), 6.88 (1H, s, AreH), 5.62 (1H, d, J ¼ 6.18 Hz, AreCHOe),
5.32 (2H, s, eOCH2e), 2.65e2.69 (1H, m, eCHCHCH3), 2.46e
2.59 (3H, m, AreCH2e, eCHCHCH3), 2.30 and 2.24 (3H each,
s, 2ꢀ AreCH3), 1.79e1.89 and 1.67e1.77 (1H each, m, Are
a
0.20 mmol) and 3-iodo phenyl boronic acid (60 mg, 0.24 mmol) as
per method described in Section 4.1.5 to give 17 (103 mg, 98% yield).
Colourless solid; mp: 179e184 ꢃC. 1H NMR (200 MHz, CDCl3):
d 8.01
(1H, d, J ¼ 8.36 Hz, Ar1eH), 7.89 (1H, s, eNCHe), 7.46e7.52 (2H, m,
2ꢀ Ar1eH), 7.26e7.29 (1H, m, Ar1eH), 6.92 (1H, s, AreH), 5.61 (1H,
d, J ¼ 6.06 Hz, AreCHOe), 5.33 (2H, s, eOCH2e), 2.65e2.69 (1H, m,
eCHCHCH3), 2.47e2.61 (3H, m, AreCH2e, eCHCHCH3), 2.30 and
2.25 (3H each, s, 2ꢀ AreCH3), 1.80e1.90 and 1.60e1.69 (1H each, m,
ArCH2CH2e), 1.39 (3H, d, J ¼ 7.32 Hz, CH3CHe). 13C NMR (100 MHz
CH2CH2e), 1.39 (3H, d,
J
¼
7.30 Hz, CH3CHe). 13C NMR
(100 MHz CDCl3):
d
179.54, 157.58 (1JCF ¼ 255.57 Hz), 154.38,
144.95, 141.39 (4JCF
¼
2.01 Hz), 134.34, 131.06, 130.16
(3JCF ¼ 4.02 Hz), 129.0, 126.35, 125.74 (3JCF ¼ 17.02 Hz), 124.85,
122.44, 115.57, 80.84 (2JCF ¼ 26.16 Hz), 75.71, 63.15, 41.83,
40.50, 23.73, 23.66, 19.94, 14.52, 11.7. IR gmax (neat): 3391,
2928, 1765, 1599, 1485, 1448, 1381, 1297, 1222, 1202, 1164, 1124,
CDCl3):
d 179.53, 154.45, 144.64, 140.28, 140.04, 134.32, 131.54,
131.03, 129.28, 128.88, 127.91, 126.36, 124.56, 115.55, 93.95, 75.73,
63.13, 41.85, 40.52, 23.74, 23.69, 20.0, 14.54, 11.78. IR gmax (neat):
3404, 2923, 1766, 1483, 1378, 1297, 1223, 1166, 1089, 1011, 987, 855,
706, 630 cmꢁ1. HRMS m/z calcd for C24H24IN3O3 [M þ H]þ
530.09351, found 530.09318.
1020, 986, 949, 903, 882, 856, 813, 769, 706, 667, 571 cmꢁ1
.
HRMS m/z calcd for
found 625.99461.
C
24H22BrFIN3O3 [M þ H]þ 625.99460,
4.1.5.17. Synthesis of 2-bromo-4,5-difluoro-1-{(5-
onin)methyl-1H-1,2,3-triazolyl}-benzene (21). The title compound
prepared by the reaction of propargylated -desmotroposantonin
a-desmotroposant-
4.1.5.14. Synthesis of 5-iodo-2-methyl-1-{(5-
methyl-1H-1,2,3-triazolyl}-benzene (18). The title compound
prepared by the reaction of propargylated -desmotroposantonin
a-desmotroposantonin)
a
(100 mg, 0.35 mmol) and 2-bromo-4,5-difluoro phenyl boronic acid
(100 mg, 0.42 mmol) as per method described in Section 4.1.5 to
give 21 (177 mg, 98% yield). Yellow solid; mp: 92e95 ꢃC. 1H NMR
a
(100 mg, 0.35 mmol) and 5-iodo-2-methyl phenyl boronic acid
(110 mg, 0.42 mmol) as per method described in Section 4.1.5 to
give 18 (187 mg, 98% yield). Yellow solid; mp: 152e154 ꢃC. 1H NMR
(200 MHz, CDCl3):
d
7.99 (1H, s, eNCHe) 7.63 (1H, dd, J ¼ 9.09 and
7.40 Hz, Ar1eH), 7.59 (1H, dd, J ¼ 9.20 and 7.44 Hz, Ar1eH), 6.90 (1H,
s, AreH), 5.61 (1H, d, J ¼ 6.18 Hz, AreCHOe), 5.31 (2H, s, eOCH2e),
2.66e2.70 (1H, m, eCHCHCH3), 2.42e2.56 (3H, m, AreCH2e, e
CHCHCH3), 2.29 and 2.25 (3H each, s, 2ꢀ Ar-CH3), 1.83e1.93 and
1.69e1.79 (1H each, m, ArCH2CH2e), 1.39 (3H, d, J ¼ 7.30 Hz,
(200 MHz, CDCl3):
d
7.79 (1H, s, NCHe), 7.74 (2H, dd, J ¼ 7.85 and
1.69 Hz, Ar1eH), 7.12 (1H, d, J ¼ 7.78 Hz, Ar1eH), 6.90 (1H, s, AreH),
5.62 (1H, d, J ¼ 6.17 Hz, AreCHOe), 5.29 (2H, s, eOCH2e), 2.65e2.69
(1H, m, eCHCHCH3), 2.41e2.55 (3H, m, AreCH2e, eCHCHCH3), 2.31
and 2.25 (3H each, s, 2ꢀ AreCH3), 2.05 (3H, s, Ar1eCH3), 1.82e1.91
and 1.66e1.75 (1H each, m, ArCH2CH2e), 1.39 (3H, d, J ¼ 7.31,
CH3CHe). 13C NMR (100 MHz, CDCl3):
d 179.51, 154.38, 151.23
1,2
(
J
¼ 256.23, 20.35 Hz), 148.56 (1,2JCF ¼ 253.56, 21.23 Hz), 144.92,
CF
CH3CHe). 13C NMR (100 MHz, CDCl3):
d
179.56, 154.41, 144.83,
134.37, 132.42 (3JCF ¼ 8.21 Hz), 131.12, 128.99, 126.30, 124.58, 122.50
138.83, 137.38, 134.57, 134.33, 133.45, 133.04, 131.04, 128.87, 126.15,
123.88, 115.22, 90.06, 75.70, 62.98, 41.80, 40.47, 23.70, 23.63, 19.97,
17.67, 14.50, 11.72. IR gmax (neat): 3711, 2926, 1767, 1594, 1482, 1379,
1298, 1225, 1165, 1120, 1044, 991, 946, 863, 827, 790, 733, 696, 658,
610 cmꢁ1. HRMS m/z calcd for C25H26IN3O3 [M þ H]þ 544.10916,
found 544.10808.
(2JCF
¼
21.09 Hz), 117.64 (2JCF
¼
21.16 Hz), 115.43, 113.43
(3JCF ¼ 7.81 Hz), 75.70, 62.95, 41.85, 40.48, 23.72, 23.66, 19.96, 14.52,
11.73. IR gmax (neat): 3830, 3477, 2929, 1765, 1601, 1509, 1377, 1296,
1224, 1165, 1121, 1040, 949, 861, 800, 705, 670, 630, 566, 528 cmꢁ1
.
HRMS m/z calcd for C24H22BrF2N3O3 [M þ H]þ 518.08853, found
518.08782.
4.1.5.15. Synthesis of 2-fluoro-5-iodo-1-{(5-
methyl-1H-1,2,3-triazolyl}-benzene (19). The title compound
prepared by the reaction of propargylated -desmotroposantonin
a
-desmotroposantonin)
4.1.5.18. Synthesis of 3-chloro-4-propoxy-1-{(5-
tonin)methyl-1H-1,2,3-triazolyl}-benzene (22). The title compound
prepared by the reaction of propargylated -desmotroposantonin
a-desmotroposan-
a
a
(114 mg, 0.40 mmol) and 2-fluoro-6-iodo-phenyl boronic acid
(128 mg, 0.48 mmol) as per method described in Section 4.1.5 to
give 19 (216 mg, 99% yield). Colourless solid; mp: 163e164 ꢃC. 1H
(86 mg, 0.30 mmol) and 3-chloro-4-propoxyphenyl boronic acid
(77 mg, 0.36 mmol) as per method described in Section 4.1.5 to give
22 (147 mg, 99% yield). Colourless solid; mp: 161e162 ꢃC. 1H NMR
NMR (200 MHz, CDCl3):
d
7.72 (1H, d, J ¼ 7.90 Hz, Ar1eH), 7.70
(200 MHz, CDCl3):
d
7.79 (1H, s, eNCHe), 7.59 (1H, d, J ¼ 8.54 Hz,
(1H, s, eNCHe), 7.18e7.24 (2H, m, 2ꢀ Ar1eH), 6.82 (1H, s, AreH),
5.54 (1H, d, J ¼ 6.16 Hz, AreCHOe), 5.27 (2H, s, eOCH2e), 2.59e
Ar1eH), 7.03 (1H, d, J ¼ 8.78 Hz, Ar1eH), 6.88 (1H, s, AreH), 5.62
(1H, d, J ¼ 6.14 Hz, AreCHOe), 5.27 (2H, s, eOCH2e), 4.05 (2H, t,
J ¼ 6.48 Hz, eOCH2CH2e), 2.59e2.63 (1H, m, eCHCHCH3), 2.42e
2.56 (3H, m, AreCH2e, eCHCHCH3), 2.31 and 2.24 (3H each, s, 2ꢀ
AreCH3), 1.92 (2H, m, eCH2CH3), 1.80e1.89 and 1.65e1.75 (1H each,
m, ArCH2CH2e), 1.39 (3H, d, J ¼ 7.31 Hz, CH3CHe), 1.09 (3H, t,
2.63 (1H, m, eCHCHCH3), 2.42e2.56 (3H, m, AreCH2e,
e
CHCHCH3), 2.28 and 2.17 (3H each, s, 2ꢀ AreCH3), 1.78e1.88 and
1.61e1.70 (1H each, m, AreCH2CH2e), 1.32 (3H, d, J ¼ 7.28 Hz,
CH3CHe). 13C NMR (125 MHz CDCl3):
d
179.65, 158.16
(1JCF ¼ 258.94 Hz), 154.35 (2JCF ¼ 19.24 Hz), 144.94, 135.28
(4JCF ¼ 3.90 Hz), 134.32, 133.12 (3JCF ¼ 7.92 Hz), 130.95, 129.53,
128.92, 126.34, 124.83, 116.91 (2JCF ¼ 19.87 Hz), 115.60, 96.99,
75.75, 63.21, 41.80, 40.52, 23.72, 23.63, 19.96, 14.51, 11.36. IR gmax
(neat): 3405, 2924, 1764, 1643, 1462, 1254, 1090, 952, 808, 700,
648, 529, 429 cmꢁ1. HRMS m/z calcd for C24H23FIN3O3 [M þ H]þ
548.08408, found 548.08447.
J ¼ 7.4 Hz, eCH2CH3). 13C NMR (125 MHz, CDCl3):
d 179.58, 155.07,
154.44, 134.37, 134.11, 131.06, 129.11, 128.82, 126.13, 124.04, 122.97,
120.15, 115.10, 113.52, 75.74, 71.06, 62.8, 41.85, 40.50, 23.76, 23.71,
22.43, 19.99, 14.52, 11.75, 10.45. IR gmax (neat): 3449, 2936, 1765,
1595, 1508, 1382, 1292, 1166, 1122, 1051, 981, 950, 856, 807, 673,
585, 540 cmꢁ1. HRMS m/z calcd for C27H30ClN3O4 [M þ H]þ
496.19976, found 496.19907.

P.K. Chinthakindi et al. / European Journal of Medicinal Chemistry 60 (2013) 365e375
373
4.1.5.19. Synthesis of 3-bromo-2-methoxy-5-methyl-1-{(5-
troposantonin)methyl-1H-1,2,3-triazolyl}-benzene (23). The title
compound prepared by the reaction of propargylated -desmo-
a
-desmo-
0.35 mmol) and 4-bromonaphthalen-1-yl-1-boronic acid (106 mg,
0.42 mmol) as per method described in Section 4.1.5 to give 26
(182 mg, 98% yield). Yellow gummy mass. 1H NMR (200 MHz,
a
troposantonin (71 mg, 0.25 mmol) and 3-bromo-2-methoxy-5-
methyl phenyl boronic acid (73 mg, 0.30 mmol) as per method
described in Section 4.1.5 to give 23 (127 mg, 97% yield). Yellow
CDCl3):
d
8.37 (1H, d, J ¼ 8.17 Hz, Ar1eH), 8.01 (1H, s, ]NCHe), 7.92
(1H, d, J ¼ 7.96 Hz, Ar1eH), 7.75e7.62 (3H, m, Ar1eH), 7.49 (1H, d,
J ¼ 7.90 Hz, Ar1eH), 6.96 (1H, s, AreH), 5.62 (1H, d, J ¼ 6.16, Are
CHOe), 5.34 (2H, s, eOCH2e), 2.66e2.70 (1H, m, eCHCHCH3),
2.41e2.55 (3H, m, AreCH2e, eCHCHCH3), 2.31 and 2.27 (3H each, s,
2ꢀ AreCH3), 1.79e1.89 and 1.61e1.72 (1H each, m, AreCH2CH2e),
1.39 (3H, d, J ¼ 7.32, CH3CHe). 13C NMR (100 MHz, CDCl3):
solid; mp: 123e125 ꢃC. 1H NMR (200 MHz, CDCl3):
d 8.21 (1H, s, e
NCHe), 7.58 (1H, d, J ¼ 1.2 Hz, Ar1eH), 7.51 (1H, d, J ¼ 1.6 Hz, Ar1e
H), 6.92 (1H, s, AreH), 5.64 (1H, d, J ¼ 6.15 Hz, AreCHOe), 5.32 (2H,
s, eOCH2e), 3.56 (3H, s, eOCH3), 2.64e2.68 (1H, m, eCHCHCH3),
2.45e2.59 (3H, m, AreCH2e, eCHCHCH3), 2.41 (3H, s, AreCH3), 2.31
and 2.26 (3H each, s, 2ꢀ AreCH3), 1.80e1.90 and 1.65e1.74 (1H
each, m, AreCH2CH2e), 1.41 (3H, d, J ¼ 7.4 Hz, CH3CHe). 13C NMR
d
179.54, 154.48, 134.39, 133.5, 132.59, 131.10, 130.90, 129.65, 129.08,
128.97,128.84,128.76,128.55,127.83,126.28,125.33,123.94,122.88,
115.41, 75.71, 63.11, 41.83, 40.50, 23.73, 23.66, 19.98, 14.51, 11.74. IR
gmax (neat): 3838, 2919, 1759, 1461, 1375, 1166, 1036, 933, 895, 809,
633, 555, 525 cmꢁ1. HRMS m/z calcd for C28H26BrN3O3 [M þ H]þ
532.12303, found 532.12173.
(100 MHz, CDCl3):
d 179.49, 154.43, 147.08, 144.92, 136.36, 134.43,
134.24, 131.34, 131.04, 128.79, 126.23, 125.34, 124.20, 117.98, 115.22,
75.69, 62.87, 61.16, 41.81, 40.49, 23.71, 23.66, 20.55, 19.95, 14.50,
11.69. IR gmax (neat): 2926, 1767, 1597, 1482, 1378, 1297, 1225, 1166,
1120, 1041, 988, 949, 856, 783, 766, 702, 568 cmꢁ1. HRMS m/z calcd
for C26H28BrN3O4 [M þ H]þ 526.13359, found 526.1333.
4.1.5.23. Synthesis of 2-(3-bromo benzyloxy)-3-bromo-1-{(5-
motroposantonin)methyl-1H-1,2,3-triazolyl}-benzene (27). The title
compound prepared by the reaction of propargylated -desmo-
a-des-
a
4.1.5.20. Synthesis of 2-bromo-6-fluoro-3-methoxy-1-{(5-
troposantonin)methyl-1H-1,2,3-triazolyl}-benzene (24). The title
compound prepared by the reaction of propargylated -desmo-
troposantonin (115 mg, 0.40 mmol) and 2-bromo-6-fluoro-3-
methoxy phenyl boronic acid (120 mg, 0.48 mmol) as per method
described in Section 4.1.5 to give 24 (207 mg, 98% yield). Colourless
a
-desmo-
troposantonin (114 mg, 0.40 mmol) and 2-{(3-bromophenoxy)
methyl}-3-bromo phenyl boronic acid (185 mg, 0.48 mmol) as per
method described in Section 4.1.5 to give 27 (263 mg, 99% yield).
a
Yellow solid mp: 147e148.5 ꢃC. 1H NMR (200 MHz, CDCl3):
d 8.10
(1H, s, eNCHe), 7.73 (2H, dd, J ¼ 8.10 and 1.42 Hz, Ar1eH), 7.37e
7.44 (2H, m, Ar1eH), 7.22 (1H, d, J ¼ 8.18 Hz, Ar1eH), 7.06e7.16
(2H, m, Ar1eH), 6.90 (1H, s, AreH), 5.60 (1H, d, J ¼ 6.14 Hz, Are
CHOe), 5.25 (2H, s, eOCH2e), 4.69 (2H, s, AreCH2Oe), 2.62e2.66
(1H, m, eCHCHCH3), 2.41e2.55 (3H, m, AreCH2e, eCHCHCH3),
2.24 (6H, s, 2ꢀ AreCH3), 1.81e1.92 and 1.65e1.76 (1H each, m, Are
CH2CH2e), 1.39 (3H, d, J ¼ 7.32 Hz, CH3CHe). 13C NMR (100 MHz,
solid; mp: 159e165 ꢃC. 1H NMR (200 MHz, CDCl3):
d 7.81 (1H, s, e
NCHe), 7.22e7.30 (1H, m, Ar1eH), 7.04e7.10 (1H, m, Ar1eH), 6.89
(1H, s, AreH), 5.62 (1H, d, J ¼ 6.15 Hz, AreCHOe), 5.32 (2H, s, eOe
CH2e), 3.95 (3H, s, eOCH3), 2.66e2.70 (1H, m, eCHCHCH3), 2.45e
2.59 (3H, m, AreCH2e, eCHCHCH3), 2.30 and 2.24 (3H each, s, 2ꢀ
AreCH3), 1.81e1.91 and 1.64e1.74 (1H each, m, AreCH2CH2e), 1.39
CDCl3):
d 179.53, 154.50, 148.19, 144.93, 137.32, 134.42, 134.28,
(3H, d, J ¼ 7.22 Hz, CH3CHe). 13C NMR (100 MHz, CDCl3):
d
179.63,
132.53, 131.80, 131.57, 131.04, 130.13, 128.79, 127.06, 126.35, 126.23,
125.37, 124.58, 122.50, 118.81, 115.11, 75.70, 75.17, 62.85, 41.85,
40.50, 23.72, 23.67, 19.97, 14.52, 11.71. IR gmax (neat): 2926, 1767,
1574, 1481, 1375, 1296, 1229, 1166, 1121, 1039, 950, 862, 787, 696,
662, 465 cmꢁ1. HRMS m/z calcd for C31H29Br2N3O4 [M þ H]þ
666.05975, found 666.05857.
154.44, 153.40 (2JCF ¼ 2.12 Hz), 152.0 (1JCF ¼ 248.34 Hz), 145.27,
134.33, 131.00, 128.96, 126.32, 125.27, 115.29, 115.62, 115.40
(2JCF ¼ 26.0 Hz), 113.86 (3JCF ¼ 8.23 Hz), 112.22, 75.76, 63.18, 57.17,
41.82, 40.54, 23.73, 23.67, 19.93, 14.50, 11.70. IR gmax (neat): 3476,
2920,1763, 1598, 1457, 1298, 1039, 947, 852, 808, 750, 699, 642, 542,
503 cmꢁ1
.
HRMS m/z calcd for C25H25BrFN3O3 [M
þ
H]þ
530.108524, found 530.1078.
4.1.5.24. Synthesis of 2-chloro-5-{(5-
1H-1,2,3-triazolyl}-pyridine (28). The title compound prepared by
the reaction of propargylated -desmotroposantonin (129 mg,
a-desmotroposantonin)methyl-
4.1.5.21. Synthesis of 2-trifluoromethyl-1-{(5-
a-desmotroposantonin)
a
methyl-1H-1,2,3-triazolyl}-benzene (25). The title compound
prepared by the reaction of propargylated -desmotroposantonin
0.45 mmol) and 6-chloro pyridine-3-yl-3-boronic acid (89 mg,
0.54 mmol) as per method described in Section 4.1.5 to give 28
(191 mg, 97% yield). Yellow solid; mp: 161e163 ꢃC. 1H NMR
a
(65 mg, 0.23 mmol) and 2-(trifluoromethyl) phenyl boronic acid
(52 mg, 0.28 mmol) as per method described in Section 4.1.5 to give
25 (105 mg, 97% yield). Colourless solid; mp: 148e150 ꢃC. 1H NMR
(200 MHz, CDCl3):
d
8.81 (1H, d, J ¼ 1.89 Hz, Ar1eH), 8.14 (1H, dd,
J ¼ 8.68 and 2.72 Hz, Ar1eH), 8.09 (1H, s, eNCHe), 7.52 (1H, d,
J ¼ 8.55 Hz, Ar1eH), 6.88 (1H, s, AreH), 5.61 (1H, d, J ¼ 6.17 Hz, Are
CHOe), 5.29 (2H, s, eOCH2e), 2.66e2.70 (1H, m, eCHCHCH3), 2.41e
2.56 (3H, m, AreCH2e, eCHCHCH3), 2.29 and 2.24 (3H each, s, 2ꢀ
AreCH3), 1.80e1.90 and 1.65e1.76 (1H each, m, AreCH2CH2e), 1.38
(200 MHz, CDCl3):
d
7.87e1.90 (2H, m, eNCHe and Ar1eH), 7.80e
7.60 (2H, m, Ar1eH), 7.59 (1H, d, J ¼ 8.16 Hz, Ar1eH), 6.89 (1H, s,
AreH), 5.62 (1H, d, J ¼ 6.18 Hz, AreCHOe), 5.32 (2H, s, eOCH2e),
2.62e2.66 (1H, m, eCHCHCH3), 2.45e2.58 (3H, m, AreCH2e, e
CHCHCH3), 2.29 and 2.24 (3H each, s, 2ꢀ AreCH3), 1.83e1.93 and
1.63e1.74 (1H each, m, AreCH2CH2e), 1.39 (3H, d, J ¼ 7.30 Hz, e
(3H, d, J ¼ 7.28 Hz, CH3CHe). 13C NMR (100 MHz, CDCl3):
d 179.64,
154.27, 151.16, 146.23, 141.16, 134.39, 132.69, 131.05, 130.79, 128.98,
126.01, 125.17, 122.73, 115.01, 75.72, 62.64, 41.75, 40.49, 23.68,
23.62, 19.95, 14.49, 11.67. IR gmax (neat): 3456, 2926, 1765, 1481,
1300, 949, 748, 692, 586, 548, 512 cmꢁ1. HRMS m/z calcd for
CH3CHe). 13C NMR (100 MHz, CDCl3):
d 179.57, 154.45, 144.78,
134.82 (2JCF ¼ 46.0 Hz), 134.36, 133.12, 131.04, 130.51, 129.07, 128.92,
127.36 (3JCF ¼ 4.16 Hz), 126.71, 126.32 (3JCF ¼ 3.2 Hz), 125.25
(4JCF ¼ 1.60 Hz), 122.63 (1JCF ¼ 272.0 Hz), 115.49, 75.74, 63.03, 41.85,
40.50, 23.72, 23.66, 19.91 14.51, 11.66. IR gmax (neat): 3436, 2927,
1766, 1600, 1460, 1314, 1127, 1041, 856, 787, 710, 666, 637, 564,
457 cmꢁ1. HRMS m/z calcd for C25H24F3N3O3 [M þ H]þ 472.18425,
found 472.18426.
C
23H23ClN4O3 [M þ H]þ 439.15314, found 439.15253.
4.1.5.25. Synthesis of 4-formyl-1-{(5-
1H-1,2,3-triazolyl}-benzene (29). The title compound prepared by
the reaction of propargylated -desmotroposantonin (71 mg,
a-desmotroposantonin)methyl-
a
0.25 mmol) and 4-formyl phenyl boronic acid (45 mg, 0.30 mmol)
as per method described in Section 4.1.5 to give 29 (105 mg, 98%
yield). Yellow solid; mp: 212e217 ꢃC. 1H NMR (200 MHz, CDCl3):
4.1.5.22. Synthesis of 4-bromo-1-{(5-
1H-1,2,3-triazolyl}-naphthalene (26). The title compound prepared
by the reaction of propargylated -desmotroposantonin (101 mg,
a-desmotroposantonin)methyl-
a
d
10.08 (1H, s, eCHO), 8.15 (1H, s, eNCHe), 8.07 (2H, d, J ¼ 8.61 Hz,

374
P.K. Chinthakindi et al. / European Journal of Medicinal Chemistry 60 (2013) 365e375
Ar1eH), 7.98 (2H, d, J ¼ 8.67 Hz, Ar1eH), 6.89 (1H, s, AreH), 5.62
(1H, d, J ¼ 6.13 Hz, AreCHOe), 5.31 (2H, s, eOCH2e), 2.63e2.67 (1H,
m, eCHCHCH3), 2.45e2.59 (3H, m, AreCH2e, eCHCHCH3), 2.31 and
2.24 (3H each, s, 2ꢀ AreCH3), 1.81e1.91 and 1.60e1.69 (1H each, m,
AreCH2CH2e), 1.39 (3H, d, J ¼ 7.27 Hz, CH3CHe). 13C NMR
12 h light/dark cycle with free access to pellet food and water. All
husbandry and experimental contact made with the mice main-
tained specific pathogen-free conditions. Animals used in experi-
mental work received humane care as per the ethical regulations
on animal research. Animals were housed and maintained
following standard guidance as found in Government of India
guidelines [38]. The study protocol was approved by Institutional
Animal Ethics Committee.
(100 MHz, CDCl3):
d 190.64, 179.57, 154.34, 146.11, 140.91, 136.06,
134.41, 131.34 (2CH), 130.91, 128.94, 128.83, 126.08, 120.56 (2CH),
115.03, 75.71, 62.79, 41.80, 40.47, 23.69, 23.63, 19.97, 14.51, 11.74. IR
gmax (neat): 3480, 2932, 1764, 1700, 1601, 1478, 1298, 1208, 1167,
1124, 987, 949, 838, 733, 672, 571, 527 cmꢁ1. HRMS m/z calcd for
4.2.1. Determination of cytotoxic effect of different samples by MTT
assay (in vitro)
C
25H25N3O4 [M þ H]þ 432.19178, found 432.19179.
MTT
[3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium
4.1.5.26. Synthesis of 3-{(5-
triazolyl}-benzamide (30). The title compound prepared by the
reaction of propargylated -desmotroposantonin (85 mg,
a
-desmotroposantonin)methyl-1H-1,2,3-
bromide] assay, first described by Mosmann in 1983, is based on
the ability of a mitochondrial dehydrogenase enzyme from viable
cells to cleave the tetrazolium rings of the pale yellow MTT and
form a dark blue formazan crystals which is largely impermeable
to cell membranes, thus resulting in its accumulation within
healthy cells. Solubilization of the cells by the addition of
a detergent results in the liberation of the crystals which are
solubilized [39e41]. The number of surviving cells is directly
proportional to the level of the formazan product created. The
colour can then be quantified using a simple colorimetric assay
[42,43]. The results can be read on a multiwell scanning spec-
trophotometer (ELISA reader) in the wavelengths of 450, 540 and
620 nm respectively.
a
0.30 mmol) and 3-carbamoyl phenyl boronic acid (60 mg,
0.36 mmol) as per method described in Section 4.1.5 to give 30
(131 mg, 98% yield). Colourless solid; mp: 210 ꢃC. 1H NMR
(200 MHz, CDCl3):
d
8.40 (1H, s, Ar1eH), 8.19 (1H, s, eNCHe), 8.09
(1H, dd, J ¼ 8.04 and 1.16 Hz, Ar1eH), 7.99 (1H, d, J ¼ 7.95 Hz, Ar1e
H), 7.72 (1H, dd, J ¼ 8.12 and 7.92 Hz, Ar1eH), 7.12 (1H, s, AreH),
5.70 (1H, d, J ¼ 6.01 Hz, AreCHOe), 5.23 (2H, s, eOCH2e), 2.65e
2.69 (1H, m, eCHCHCH3), 2.44e2.58 (3H, m, AreCH2e,
e
CHCHCH3), 2.23 and 2.19 (3H each, s, 2ꢀ AreCH3), 1.81e1.91 and
1.45e1.59 (1H each, m, ArCH2CH2e), 1.27 (3H, d, J ¼ 7.4 Hz, CH3CHe
). 13C NMR (125 MHz, CDCl3):
d
179.60, 167.20, 154.44, 145.05,
Methodology: Animals (Balb/c mice, 18e22 g) were sacrificed;
their spleens were removed in sterile conditions. A single cell
suspension was prepared in 5 mL of incomplete RPMI. The cell
suspension was centrifuged at 1200 rpm for 10 min and superna-
tant was discarded. RBCs were lysed by Tris-ammonium chloride
treatment. The cells were centrifuged twice at 1200 rpm for 10 min,
supernatant discarded and resuspended in complete RPMI. The
viability of cells was checked with trypan blue. 1 ꢀ 106 cells/mL
137.04, 136.44, 134.44, 131.52, 130.45, 129.31, 128.06, 125.30, 123.25,
123.09, 119.66, 115.54, 75.61, 62.41, 41.18, 40.41, 23.65, 23.54, 19.99,
14.60, 11.93. IR gmax (neat): 3732, 3314, 2918, 1764, 1681, 15,852,
1461, 1299, 1170, 1126, 1050, 994, 944, 899, 845, 775, 720, 654 cmꢁ1
.
HRMS m/z calcd for C25H26N4O4 [M þ H]þ 447.20268, found
447.20242.
4.1.5.27. Synthesis of 1-N-acetyl-4-{(4-(5-
methyl-1H-1,2,3-triazolyl}phenyl)-aniline (31). The title compound
prepared by the reaction of propargylated -desmotroposantonin
a-desmotroposantonin)
suspension was prepared and 100
of 96 well microtitre plate (Flat bottom). An aliquot of 50
standard mitogens (ConA ¼ 10 g/mL and LPS ¼ 10 g/mL) and test
materials were added according to the experimental setup. 50 L of
drug of interest of different concentrations (1, 10 and 100 M) (1e
mL of it was poured in each well
mL of
a
m
m
(99.5 mg, 0.35 mmol) and 4-carbamoyl phenyl boronic acid (75 mg,
0.42 mmol) as per method described in Section 4.1.5 to give 31
(159 mg, 99% yield). Yellow solid; mp: 175e179 ꢃC. 1H NMR
m
m
31) was dissolved in DMSO and added to each well of flat bottom
microtitre 96 well plate. Plates were placed on a shaker for 5 min to
thoroughly mix the samples into the media.
(200 MHz, CDCl3):
d
7.92e7.98 (2H, m, Ar1eH and eNCHe), 7.84
(1H, d, J ¼ 6.54 Hz, Ar1eH), 7.36e7.43 (2H, m, Ar1eH), 6.90 (1H, s,
AreH), 5.63 (1H, d, J ¼ 6.14 Hz, AreCHOe), 5.26 (2H, s, eOCH2e),
2.62e2.66 (1H, m, eCHCHCH3), 2.46e2.58 (3H, m, AreCH2e, e
CHCHCH3), 2.21 (9H, s, 2ꢀ AreCH3 and eNCOCH3), 1.83e1.93 and
1.64e1.71 (1H each, m, AreCH2CH2e), 1.39 (3H, d, J ¼ 7.24 Hz,
The plates were incubated for 48 h in CO2 incubator (37 ꢃC, 5%
CO2 and 90% relative humidity). After 48 h incubation, plates were
taken out from the CO2 incubator.10 mL of MTT solution (5 mg/mL in
PBS) was added to each well (MTT in solution is not stable for long-
term). The contents were placed on a shaker for 5 min to thor-
oughly mix the MTT into the media. Plates were incubated for 4e
6 h in CO2 incubator (37 ꢃC, 5% CO2 and 90% relative humidity) to
allow the MTT to be metabolized. Centrifuged the plates at
2000 rpm for 10 min. Removed the medium (dry plate on paper
towels to remove residue if necessary). Resuspended formazan
CH3CHe). 13C NMR (125 MHz, CDCl3):
d 180.10, 169.24, 154.27,
145.01, 139.83, 137.12, 134.52, 130.87, 130.23 (2CH), 129.14, 126.50,
120.02, 116.06, 115.85, 111.70, 76.03, 63.23, 41.62, 40.45, 24.42,
23.54, 23.48, 19.91, 14.43, 11.70. IR gmax (neat): 3477, 2922, 1770,
1472, 1346, 1049, 778, 688, 644, 558, 548, 490 cmꢁ1. HRMS m/z
calcd for C26H28N4O4 [M þ H]þ 461.21833, found 461.21749.
crystals (MTT metabolic product) in 100 mL of DMSO. Mechanically
4.2. Biology
mixed the plate until formazan crystals were dissolved. Read in
a microculture plate reader at test and reference wavelengths of
450, 540 and 620 nm respectively. The mean of the optical density
of plates were calculated and evaluate the percentage of each value
verses control.
Mitogens and reagents: Concanavalin A (ConA), lipopolysaccha-
ride (LPS, Escherichia coli 055:B5), 3-[4,5-dimethylthiazol-2-yl]-2,5-
diphenyl-tetrazolium bromide (MTT), and 3,30,5,50-tetrame-
thylbenzidine (TMB) were procured from Sigma Aldrich. RPMI
(Roswell Park Memorial Institute) 1640 medium was purchased
from Gibco BRL, Life Technologies (USA). Fetal bovine serum (FBS)
was purchased from HyClone Laboratories (Utah, USA). Animals.
Balb/c mice 10e12 week old and weighing 20e24 g obtained from
animal house of Indian Institute of Integrative Medicine, Jammu
were taken up in groups of six and employed for the study. These
animals were maintained at a room temperature of 26 ꢂ 2 ꢃC with
Acknowledgements
The authors are thankful Taxonomists of institute (Dr SN
Sharma and S. Kitchalu) for providing the authentic plant material.
Authors (PKC, SF and RRA) thank Council of Scientific and Indus-
trial Research (CSIR-UGC), New Delhi for the award of senior
research fellowships. Staff of instrumentation division (NMR) of

P.K. Chinthakindi et al. / European Journal of Medicinal Chemistry 60 (2013) 365e375
375
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