Synthesis and antileishmanial activity of novel 2,4,6-trisubstituted pyrimidines and 1,3,5-triazines

Article abstract of DOI:10.1016/j.ejmech.2009.01.016

A series of 2,4,6-trisubstituted pyrimidines and 1,3,5-triazines have been synthesized and screened for their in vitro and in vivo antileishmanial activity against Leishmania donovani. Among all, 14 compounds have shown promising inhibition of 80-100% at

Full text of DOI:10.1016/j.ejmech.2009.01.016

European Journal of Medicinal Chemistry 44 (2009) 2473–2481
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European Journal of Medicinal Chemistry
journal homepage: http://www.elsevier.com/locate/ejmech
Original article
Synthesis and antileishmanial activity of novel 2,4,6-trisubstituted pyrimidines
and 1,3,5-triazines
,
b
Naresh Sunduru a, Nishi b, Shraddha Palne b, Prem M.S. Chauhan a , Suman Gupta
*
a Division of Medicinal Chemistry, Central Drug Research Institute, MG Road, Lucknow 226001, UP, India
b Division of Parasitology, Central Drug Research Institute, Lucknow 226001, UP, India
a r t i c l e i n f o
a b s t r a c t
Article history:
A series of 2,4,6-trisubstituted pyrimidines and 1,3,5-triazines have been synthesized and screened for
Received 16 September 2008
Received in revised form
12 January 2009
Accepted 15 January 2009
Available online 27 January 2009
their in vitro and in vivo antileishmanial activity against Leishmania donovani. Among all, 14 compounds
have shown promising inhibition of 80–100% at 10
mg/ml against promastigotes and IC50 in the range of
0.89–9.68 g/ml against amastigotes. Three compounds 13, 32 and 33 with good selectivity index (S.I.)
m
were screened for their in vivo activity in golden hamsters (Mesocricetus auratus) infected with MHOM/
IN/80/Dd8 strain of L. donovani and have shown moderate in vivo inhibition of 48–56% at a dose of 50 mg/
kg ꢀ 5, i.p. route for 5 days.
Keywords:
Ó 2009 Published by Elsevier Masson SAS.
Leishmaniasis
Pyrimidine
1,3,5-Triazine
1. Introduction
a safe treatment in all clinical cases [5]. So, there is an urgent need
to develop safer, cheaper and more effective chemotherapy.
Leishmaniasis, a parasitic disease caused by protozoal species
of the genus Leishmania is transmitted by the bite of more than
30 different species of sand flies [1]. This disease is currently
prevalent in four continents, being endemic in 88 countries. The
most severe form, visceral leishmaniasis (VL), known as kala-azar,
is nearly always fatal if not treated. It is estimated that about half
a million people die annually with visceral leishmaniasis and over
350 million people live at risk of this infection [2]. In spite of this,
AIDS and other immunosuppressive conditions have also enhanced
the risk of Leishmania–HIV co-infected people and contributed to
the appearance of new severe clinical forms of the disease [3]. The
current chemotherapy to the leishmaniasis still poses a serious
problem. The drugs of first choice are pentavalent antimonial
compounds, which were developed before 1960, and in general,
require long-term treatment and have severe side effects. But
leishmania parasites have developed resistance to these antimo-
nials since 1990s [4]. Presently, amphotericin B and the oral
anticancer drug miltefosine are considered to be the best second-
line therapeutic solutions. Nevertheless, they do not represent
Dihydrofolate reductase (DHFR) has successfully been used as
a drug target in the area of parasitic diseases. But most of the
clinically used DHFR inhibitors show less selectivity for leishmanial
enzymes [6]. This is due to the over expression of the gene pteridine
reductase (PTR1) in some leishmanial mutants. This PTR1 has
ability to provide reduced pterins and folates and has the potential
to act as a by-pass or modulator of DHFR inhibition. Thus to stop the
folate biosynthesis that is essential for the survival of leishmania,
both PTR1 and DHFR have to be inhibited [7]. Selective inhibitors of
PTR1 or a single inhibitor that acts on both enzymes would
constitute a rational approach for new antileishmanial agents.
Earlier, pyrimidines were synthesized and evaluated as inhibitors of
leishmanial and trypanosomal dihydrofolate reductase [8], while
triazine class of compounds being the inhibitors of DHFR [9–11]
have also been identified as potential antileishmanial agents
[12,13]. Based on these observations we have designed and
synthesized a class of hybrid molecules having pyrimidine along
with triazine moiety and substituted pyrimidines.
As our ongoing research devoted to the synthesis of diverse
heterocycles as anti-infective agents, we had previously reported
antiparasitic activity in substituted pyrimidines, pyridines,
triazines, and quinolines [12–22]. This communication describes
the synthesis and in vitro, in vivo antileishmanial activity of
2,4,6-trisubstituted pyrimidines and 1,3,5-triazines.
* Corresponding author. Tel.: þ91 522 2262411x4470; fax: þ91 522 2623405.
E-mail addresses: prem_chauhan_2000@yahoo.mail.com, premsc58@hotmail.-
com (P.M.S. Chauhan).
0223-5234/$ – see front matter Ó 2009 Published by Elsevier Masson SAS.
doi:10.1016/j.ejmech.2009.01.016

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N. Sunduru et al. / European Journal of Medicinal Chemistry 44 (2009) 2473–2481
2. Chemistry
serum and the plates were incubated at 37 ꢂC in a CO2 incubator.
After 24 h, the medium was replaced with fresh medium containing
To synthesize the 2,4,6-trisubstituted-1,3,5-triazine compounds
(8–29), substituted acetophenone was reacted with CS2 in the
presence of NaH in dry THF, followed by methylation with methyl
iodide [23] to yield corresponding 3,3-bis-methylsulfanyl-1-
(substituted-phenyl)-propenones (1, 2). The compounds 1, 2 were
cyclized with guanidine hydrochloride in the presence of sodium
hydride in DMF [24] to obtain corresponding 4-(substituted-
phenyl)-6-methylsulfanyl-pyrimidin-2-ylamines (3, 4). Compounds
3, 4 were further reacted with cyanuric chloride (2,4,6-trichloro-
1,3,5-triazine) in the presence of K2CO3 in dry THF to obtain the
corresponding (4,6-dichloro-[1,3,5]triazin-2-yl)-[4-(substituted-
phenyl)-6-methylsulfanyl-pyrimidin-2-yl]-amines (5, 6), which
were subjected to nucleophilic substitution with different amines
(Table 1) to afford the final targeted compounds (Scheme 1).
stationary phase promastigotes (2.25 ꢀ105/100
ml/well). Promasti-
gotes invade the macrophage and are transformed into amasti-
gotes. The test material in appropriate concentrations (0.25–10 mg/
ml) in complete medium was added after replacing the previous
medium and the plates were incubated at 37 ꢂC in a CO2 incubator
for 72 h. After incubation, the drug containing medium was
decanted and 50 ml PBS was added in each well and mixed with
an equal volume of Steady GloÒ reagent. After gentle shaking
for 1–2 min, the reading was taken in a luminometer [25]. The
inhibition of parasitic growth is determined by comparison of the
luciferase activity of drug treated parasites with that of untreated
controls as described above.
In vivo activity: The in vivo leishmanicidal activity was
determined in golden hamsters (Mesocricetus auratus) infected
with MHOM/IN/80/Dd8 strain of L. donovani obtained through the
courtesy of P.C.C. Garnham, Imperial College, London (UK). For
in vivo evaluation of compounds, the method of Beveridge [26] as
modified by Bhatnagar et al. [27] and Gupta et al. [28] was
employed. Golden hamsters (of either sex) weighing 40–45 g were
infected intracardially with 1 ꢀ107 amastigotes per animal.
Pretreatment spleen biopsy in all the animals was carried out to
assess the degree of infection. The animals with þ1 infection (5–15
amastigotes/100 spleen cell nuclei) were included in the chemo-
therapeutic trials. The infected animals are randomized into several
groups on the basis of their parasitic burdens. Four to six animals
were used for each test sample. Drug treatment by i.p. route is
initiated after 2 days of biopsy and continued for 10 consecutive
days. Post-treatment biopsies are done on day 7 of the last drug
administration and amastigote counts are assessed by Giemsa
staining. Intensity of infection in both, treated and untreated
animals, as also the initial count in treated animals is compared
and the efficacy is expressed in terms of percentage inhibition (PI)
using the following formula:
To synthesize 2,4,6-trisubstituted pyrimidines,
3
was
oxidized to corresponding sulfone 4-(methylsulfonyl)-6-(3,4,5-
trimethoxyphenyl)pyrimidin-2-amine (7) in the presence of
m-chloroperoxybenzoic acid (2.5 equiv) in dry DCM. The sulfone 7
was subjected to nucleophilic substitution with various amines
(Table 1) in closed steel vessel to yield targeted compounds 30–36
[24]. All the synthesized compounds were well characterized
by spectroscopic methods such as IR, mass, NMR and elemental
analyses.
3. Biological activities
3.1. Materials and methods
3.1.1. Antipromastigote activity
The Leishmania donovani promastigotes (MHOM/IN/80/Dd8;
originally obtained from Imperial College, London) were trans-
fected with firefly luciferase gene and the transfectants were
maintained in medium 199 (Sigma Chemical Co., USA) supple-
mented with 10% foetal calf serum (GIBCO) and 1% penicillin
PI ¼ 100 ꢁ ðANAT ꢀ 100=INAT ꢀ TIUCÞ
(50 U/ml), streptomycin (50 mg/ml) solution (Sigma) under pres-
where PI is the percentage inhibition of amastigotes’ multiplica-
tion; ANAT is Actual Number of amastigotes in treated animals;
INAT is Initial Number of amastigotes in treated animals and TIUC
is Times Increase of parasites in untreated control animals.
sure of G418 (Sigma). The in vitro effect of the compounds on the
growth of promastigotes was assessed by monitoring the luciferase
activity of viable cells after treatment. The transgenic promasti-
gotes of late log phase were seeded in 5 ꢀ105/100
ml medium 199 in
96-well flat-bottomed microtiter (MT) plates (CELLSTAR) and
incubated for 72 h in medium alone or in the presence of serial
3.1.3. Data analysis
IC50 was calculated by Probit analysis [29]. Compounds with more
dilutions of drugs (1–10
DMSO were used as controls. After incubation, an aliquot (50
m
g/ml) in DMSO [25]. Parallel dilutions of
l) of
than 15
with IC50 between 15 and 5
active and less than 5 g/ml are highly active compounds.
mg/ml IC50 were considered as inactive while compounds
m
mg/ml were considered as moderately
promastigote suspension was aspirated from each well of a 96-well
plate and mixed with an equal volume of Steady GloÒ reagent
(Promega) and luminescence was measured by a luminometer.
The values were expressed as relative luminescence unit (RLU). The
inhibition of parasitic growth is determined by comparison of the
luciferase activity of drug treated parasites with that of untreated
controls by the general formula:
m
3.1.4. Cytotoxicity assay
The cell viability was determined using the MTT assay. J774A.1
cell line was maintained in RPMI medium (Sigma), supplemented
with 10% foetal calf serum and 40 mg/ml gentamycin. Exponentially
growing cells (1 ꢀ104 cells/100
ml/well) were incubated with
N ꢁ n ꢀ 100
different drug concentrations for 72 h and were incubated at 37 ꢂC in
a humidified mixture of CO2 and 95% air in an incubator. Stock
solutions of compounds were initially dissolved in DMSO and
Percentageinhibition ¼
N
where N is average relative luminescence unit (RLU) of control
wells and n is average RLU of treated wells.
further diluted with fresh complete medium. After incubation, 25 ml
of MTT reagent (5 mg/ml) in PBS medium, followed by syringe
filtration were added to each well and incubated at 37 ꢂC for 2 h. At
the end of the incubation period, the supernatant was removed by
3.1.2. Antiamastigote activity
In vitro activity: For assessing the activity of compounds against
the amastigote stage of the parasite, mouse macrophage cell line
(J774A.1) infected with promastigotes expressing luciferase firefly
reporter gene was used. Cells were seeded in a 96-well plate
tilting plate completely without disturbing cell layer and 150 ml of
pure DMSO are added to each well. After 15 min of shaking the
readings were recorded as absorbance at 544 nm on a microplate
reader. The cytotoxic effect was expressed as 50% lethal dose, i.e., as
(1.5 ꢀ104 cells/100
ml/well) in RPMI-1640 containing 10% foetal calf

N. Sunduru et al. / European Journal of Medicinal Chemistry 44 (2009) 2473–2481
2475
Table 1
Antileishmanial in vitro activity against luciferase–promastigote system.
R2
Comp. no.
(R1 ¼ OCH3)
% Inhibition at 10
promastigote
m
g/ml
Comp. no.
(R1 ¼ H)
% Inhibition at 10
promastigote
mg/ml
Comp. % Inhibition at 10 mg/ml
no.
promastigote
HN(H2C)2
HN(H2C)3
N
N
O
O
8
9
42.5
75.2
19
20
NI
30
68.5
35.2
31
46.9
H
N
N
10
11
12
NI
21
22
23
94.7
78.6
NI
32
33
–
95.10
84.4
–
HN
75.5
95.8
HN
N
13
90.8
24
53.8
34
88
N
N CH3
14
15
16
99.5
86.7
80.8
25
26
27
99.8
85.6
90.5
35
–
63.88
N
H
–
N
O
36
43.90
N
17
18
94.5
100
28
29
NI
NI
–
–
–
–
H
N
N C2H5
PentamidineÒa
SSGÒ (sodium stibogluconate)b
NI: no inhibition.
a
Pentamidine shows 85–90% inhibition against promastigotes at 0.5 mg/ml.
SSG shows 40–50% inhibition against promastigotes at 940 mg/ml.
b
the concentration ofa compound whichprovokeda 50%reduction in
cell viability compared to cell in culture medium alone. IC50 values
were estimated through the preformed template as described by
Huber and Koella [30].
L. donovani. The percentage inhibition of these compounds against
promastigotes has been given in Table 1. Among all twenty-nine
synthesized compounds, fourteen compounds have shown more
than 80% inhibition at 10 mg/ml against promastigotes and were
further screened against amastigote model. Their IC50, CC50 and S.I.
values have been given in Table 2.
4. Results and discussion
Among all tested fourteen compounds, four compounds (13, 14,
17 and 25) have shown IC50 in the range of 0.8–2.0
compounds (12, 18, 21, 26 and 33) in the range of 2.0–5.0
m
g/ml and five
Biological activity of 2,4,6-trisubstituted-1,3,5-triazines (8–29)
and pyrimidines (30–36) hasve shown encouraging results against
mg/ml

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N. Sunduru et al. / European Journal of Medicinal Chemistry 44 (2009) 2473–2481
OCH3
OCH3
H3CO
R1
H3CO
R1
SCH3
SCH3
a
O
1, 2
O
R1=H, OC H3
b
OCH3
H3CO
SCH3
R1
N
N
c
d
OCH3
NH2
3, 4
H3CO
R1
SCH3
OCH3
H3CO
H3CO
N
N
O
SCH3
O
NH
N
N
N
N
NH2
Cl
N
Cl
7
5, 6
f
e
OCH3
OCH3
H3CO
R1
H3CO
H3CO
SCH3
R2
N
N
N
N
NH
NH2
30-36
N
N
R2
N
R2
8-29
Scheme 1. Reagents and conditions: (a) CS2, NaH, MeI, THF, 0 ꢂC to reflux; (b) guanidine hydrochloride, NaH, DMF, reflux; (c) cyanuric chloride, K2CO3, THF, reflux; (d) m-CPBA,
DCM, 0 ꢂC to rt; (e) various amines, K2CO3, THF, reflux; (f) different amines, THF, 100 ꢂC, in closed steel vessel.
against amastigotes. Compound 25 consisting of 3,4-dimethox-
yphenyl group at the fourth position of pyrimidine and N-methyl-
piperazine at the 4,6 position of 1,3,5-triazine has shown the lowest
MHOM/IN/80/Dd8 strain of L. donovani. Compounds 13, 33 have
shown above moderate percentage inhibition of 56.58 and 54.10
respectively, while compound 32 has shown moderate inhibition of
48.46%. Structure–activity relationship (SAR) shows that the 3,4,5-
trimethoxyphenyl group at the fourth position of pyrimidine ring
incorporated with 1,3,5-triazine enhances the antileishmanial
activity.
IC50 of 0.89 mg/ml and has the maximum S.I. (selectivity index)
value of 40.71, which is several folds better than the standard drugs
(pentamidine, SSG). While compound 13 having 3,4,5-trimethox-
yphenyl group at the fourth position of pyrimidine and piperidine
at the 4,6 position of 1,3,5-triazine showed IC50 of 1.80
m
g/ml with
In conclusion, compounds 13, 25, 32 and 33 have shown better
selectivity index in comparison to pentamidine and sodium sti-
bogluconate. As a consequence of the above results and consid-
erations, these hybrid molecules can be served as promising
prototypes for the development of potent antileishmanial agents.
less cytotoxicity value of CC50 51.67 g/ml in comparison to
m
compound 25. Similarly compounds 32 and 33 consisting of
3,4,5-trimethoxyphenyl group at the fourth position and N,N-
diethylethylenediamine and butylamine at the sixth position
of pyrimidine respectively, showed IC50 of 5.12, 4.99
mg/ml and
cytotoxicity (CC50) of 81.52 and 49.93 g/ml. Due to their lower
m
5. Experimental
cytotoxicity and better selectivity index (28.70, 15.92 and 10.00),
compounds 13, 32 and 33 were screened for in vivo anti-
leishmanial activity in golden hamsters (M. auratus) infected with
IR spectra were recorded on Beckman Aculab-10, Perkin Elmer
881 and FTIR Shimadzu 8201PC spectrophotometers either on KBr

N. Sunduru et al. / European Journal of Medicinal Chemistry 44 (2009) 2473–2481
2477
Table 2
In vitro (against MQ amastigotes) and in vivo antileishmanial activity.
5.2. General procedure for the synthesis of compounds 3, 4
To a suspension of NaH (1.5 equiv) and compounds 1, 2 (1 equiv)
in dry DMF was added guanidine hydrochloride (1.5 equiv). The
reaction mixture was refluxed with stirring for 12 h. The solvent
was removed under vacuum and the resultant residue was purified
by using column chromatography to obtain the respective
compounds 3, 4 yielding in the range of 60–70%.
Comp. no.
In vitro
Cytotoxicity
S.I.
In vivo % inhibition
antiamastigote against J774A.1 (selectivity 50 mg/kg ꢀ 5, i.p. for
activity IC50
g/ml)
cell lines CC50
index)
CC50/IC50
5 days in hamstersa
(
m
(
m
g/ml)
12
13
14
15
16
17
18
21
25
26
27
32
33
34
2.97
1.80
1.34
ND
9.80
3.29
28.70
12.34
–
ND
56.58
ND
ND
ND
ND
ND
ND
ND
ND
ND
48.46
54.10
ND
84.10 (20 mg/kg)
92 (40 mg/kg)
51.67
16.54
1.46
10.85
1.90
27.36
42.01
36.24
14.34
23.85
81.52
49.93
10.45
31.31
7.02
1.04
4.56
4.88
0.89
2.27
9.68
5.12
4.99
7.09
1.54
1.82
6.00
8.60
40.71
6.31
2.46
15.92
10.00
1.47
5.2.1. 4-Methylsulfanyl-6-(3,4,5-trimethoxyphenyl)-pyrimidin-2-
ylamine (3)
Yield: 65%; mp 112–115 ꢂC; FAB-MS: 308 (M þ 1); IR (KBr):
3448, 3341, 3211, 3002, 2934, 2833, 1637, 1558, 1422,1348, 1225,
1128, 1008, 820 cmꢁ1; 1H NMR (200 MHz, CDCl3): 7.19 (s, 2H), 6.88
(s, 1H), 5.08 (br-s, 2H), 3.94 (s, 6H), 3.89 (s, 3H), 2.55 (s, 3H). 13C
NMR (75 MHz, CDCl3): 171.60,162.96, 162.41, 153.36,140.04,132.72,
104.73, 104.19, 60.96, 56.24, 12.42. Anal. Calcd for C14H17N3O3S: C,
54.71; H, 5.57; N, 13.67. Found: C, 54.68; H, 5.69; N, 13.46.
PentamidineÒ 12.11
2.58
5.53
SSGÒ
53.62
297
a
5.2.2. 4-(3,4-Dimethoxyphenyl)-6-methylsulfanyl-pyrimidin-2-
ylamine (4)
The in vivo leishmanicidal activity was determined in golden hamsters (Meso-
cricetus auratus) infected with MHOM/IN/80/Dd8 strain of L. donovani. ND: not done.
Yield: 63%; mp 107–110 ꢂC; FAB-MS: 277 (M þ 1); IR (KBr): 3387,
3319, 3195, 2929, 2837, 1644, 1550, 1516, 1426,1344, 1262, 1133,
discs or in neat. Nuclear magnetic resonance (NMR) spectra were
recorded on either Bruker Avance DRX-300 MHz or Bruker DPX 200
FT spectrometer using TMS as an internal reference. FAB mass
spectra were recorded on JEOL SX 102/DA 6000 mass spectrometer
using Argon/Xenon (6 kV, 10 mA) as the FAB gas. Chemical analysis
was carried out on Carlo-Erba-1108 instrument. The melting points
were recorded on an electrically heated melting point apparatus
and are uncorrected.
1025, 795 cmꢁ1
;
1H NMR (300 MHz, CDCl3): 7.60 (d, 1H,
J ¼ 2.89 Hz), 7.53 (dd, 1H, J ¼ 2.93, 8.38 Hz), 6.95 (s, 1H) 6.91 (S, 1H),
5.09 (br-s, 2H), 3.99 (s, 3H), 3.95 (s, 3H), 2.56 (s, 3H). 13C NMR
(75 MHz, CDCl3): 171.38, 162.91, 162.44, 151.04, 149.07, 129.89,
120.01, 110.82, 109.83, 104.13, 55.98, 12.45. Anal. Calcd for
C13H15N3O2S: C, 56.30; H, 5.45; N, 15.15. Found: C, 56.51; H, 5.38;
N, 15.09.
5.1. General procedure for the synthesis of compounds 1, 2
5.3. General procedure for the synthesis of compounds 5, 6
The mixture, 1 equiv of substituted acetophenone and 1 equiv of
carbondisulfide in dry THF, was added dropwise to an ice-cold
stirred suspension of NaH (2 equiv) in dry THF over a period of
30 min. The reaction mixture was stirred at room temperature for
4 h. Methyl iodide (2.5 equiv) was added in excess to the reaction
mixture at 0 ꢂC for 5 min. The reaction mixture was stirred addi-
tionally for 12 h at room temperature. The solvent was removed
under reduced pressure and the resultant residue was dissolved in
chloroform. The organic phase was washed with water (three
times), dried over anhydrous Na2SO4. The solution was concen-
trated and crystallized from CHCl3–hexane to afford the respective
compounds 1, 2 yielding in the range of 75–80%.
The solution of compounds 3, 4 (1 equiv) in dry THF was added
dropwise to an ice-cold mixture of cyanuric chloride (1.5 equiv) and
K2CO3 (2 equiv) in dry THF. The reaction mixture was stirred at
room temperature for 1 h and then refluxed with stirring for 8 h.
The reaction mixture was filtered and solvent was evaporated
under vacuum to dryness. The solid mass was purified by using
column chromatography within
a day to afford respective
compounds 5, 6 yielding in the range of 70–75%.
5.3.1. (4,6-Dichloro-[1,3,5]triazin-2-yl)-[4-methylsulfanyl-6-(3,4,5-
trimethoxyphenyl)-pyrimidin-2-yl]-amine (5)
Yield: 72%; mp > 200 ꢂC (decomposes); FAB-MS: 455 (M þ 1); IR
(KBr): 3238, 3032, 2963, 2849, 1607, 1560, 1514, 1397, 1267, 1152,
1006, 831 cmꢁ1; 1H NMR (300 MHz, 75% CDCl3 þ 25% CD3OD): 7.42
(s, 2H), 7.00 (s, 1H), 4.06 (s, 6H), 4.00 (s, 3H), 2.66 (s, 3H). 13C NMR
(75 MHz, 75% CDCl3 þ 25% CD3OD): 184.49, 176.33, 169.49, 158.91,
158.36, 157.58, 155.45, 130.04, 112.96, 112.08, 64.76, 60.68, 16.86.
Anal. Calcd for C17H16Cl2N6O3S: C, 44.84; H, 3.54; N, 18.46. Found:
C, 44.73; H, 3.43; N, 18.37.
5.1.1. 3,3-Bis-methylsulfanyl-1-(3,4,5-trimethoxyphenyl)-
propenone (1)
Yield: 80%; mp 136–139 ꢂC; FAB-MS: 315 (M þ 1); IR (KBr):
3029, 2855, 1691, 1615, 1575, 1495, 1372 cmꢁ1 1H NMR (200 MHz,
;
CDCl3): 6.82 (s, 2H), 6.25 (s, 1H), 3.85 (s, 6H), 3.79 (s, 3H), 2.52 (s,
3H), 2.46 (s, 3H). 13C NMR (75 MHz, CDCl3): 184.75, 166.54, 153.01,
141.46, 134.80, 109.22, 105.28, 60.94, 56.31, 17.38, 15.15. Anal. Calcd
for C14H18O4S2: C, 53.48; H, 5.77. Found: C, 53.62; H, 5.73.
5.3.2. (4,6-Dichloro-[1,3,5]triazin-2-yl)-[4-(3,4-dimethoxyphenyl)-
6-methylsulfanyl-pyrimidin-2-yl]-amine (6)
5.1.2. 1-(3,4-Dimethoxyphenyl)-3,3-bis-methylsulfanyl-propenone
(2)
Yield: 70%; mp > 200 ꢂC (decomposes); FAB-MS: 425 (M þ 1); IR
(KBr): 3367, 3173, 3082, 2926, 2838, 1602, 1574, 1518, 1432, 1237,
Yield: 75%; mp 118–121 ꢂC; FAB-MS: 285 (M þ 1); IR (KBr):
3033, 2865, 1695, 1612, 1574, 1493, 1370 cmꢁ1; 1H NMR (300 MHz,
1157, 1157, 1015, 848 cmꢁ1
;
1H NMR (300 MHz, 75% CDCl3 þ 25%
CDCl3):
d
(ppm) 7.61 (d, 1H, J ¼ 2.86 Hz), 7.51 (dd, 1H, J ¼ 2.78,
CD3OD): 7.63 (d, 1H, J ¼ 2.84 Hz), 7.53 (dd, 1H, J ¼ 2.87, 8.32 Hz),
8.45 Hz), 6.88 (d, 1H, J ¼ 8.32 Hz), 6.78 (s, 1H), 3.95 (s, 3H), 3.93 (s,
3H), 2.58 (s, 3H), 2.54 (s, 3H). 13C NMR (75 MHz, CDCl3): 184.43,
166.15, 152.24, 149.06, 132.30, 123.31, 121.32, 110.63, 109.89, 109.27,
56.02, 55.94, 17.34, 15.11. Anal. Calcd for C13H16O3S2: C, 54.90; H,
5.67. Found: C, 54.81; H, 5.59.
6.98 (s, 1H) 6.90 (S, 1H), 4.06 (s, 3H), 4.02 (s, 3H), 2.63 (s, 3H). 13C
NMR (75 MHz, 75% CDCl3 þ 25% CD3OD):
d (ppm) 184.53, 176.12,
169.58, 159.10, 158.40, 157.22, 155.51, 129.24, 113.70, 112.39, 107.52,
59.91, 17.57. Anal. Calcd for C16H14Cl2N6O2S: C, 45.19; H, 3.32; N,
19.76. Found: C, 45.15; H, 3.26; N, 19.81.

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N. Sunduru et al. / European Journal of Medicinal Chemistry 44 (2009) 2473–2481
5.4. General procedure for the synthesis of compounds 8–29
142.18, 133.56, 110.19, 106.26, 63.89, 59.34, 31.84, 15.62. Anal. Calcd
for C25H36N8O3S: C, 56.80; H, 6.86; N, 21.20. Found: C, 56.74; H,
6.69; N, 21.24.
The mixture of compounds 5, 6 (1 equiv), different amines
(2 equiv) listed in Table 1, and K2CO3 (2 equiv) in dry THF was
refluxed for 8 h. The reaction mixture was filtered and the solvent
was evaporated under vacuum. The solid residue was purified with
column chromatography using silica gel as adsorbent to obtain
respective compounds 8–29 in good yield.
5.4.6. N-(4-(Methylthio)-6-(3,4,5-trimethoxyphenyl)pyrimidin-
2-yl)-4,6-di(piperidin-1-yl)-1,3,5-triazin-2-amine (13)
Yield: 84%; mp 113–115 ꢂC; FAB-MS: 553 (M þ 1); IR (KBr): 3430,
2927, 2852, 1591, 1386, 1124, 1018, 806, 753 cmꢁ1
;
1H NMR
(300 MHz, CDCl3):
d (ppm) 7.28 (s, 2H), 7.10 (s, 1H), 5.29 (br-s, 1H),
5.4.1. N2-(4-(Methylthio)-6-(3,4,5-trimethoxyphenyl)pyrimidin-2-
yl)-N4,N6-bis(2-morpholinoethyl)-1,3,5-triazine-2,4,6-triamine (8)
Yield: 67%; mp 164–167 ꢂC; FAB-MS: 643 (M þ 1); IR (KBr):
3.96 (s, 6H), 3.92 (s, 3H), 3.81 (m, 8H), 2.68 (s, 3H), 1.69–1.59 (m,
12H). 13C NMR (75 MHz, CDCl3): 170.17, 163.84, 162.40, 161.12,
156.84, 152.10, 139.14, 131.07, 107.64, 104.81, 61.14, 56.41, 44.14,
25.73, 23.63,12.51. Anal. Calcd for C27H36N8O3S: C, 58.67; H, 6.57; N,
20.27. Found: C, 58.73; H, 6.49; N, 20.31.
3385, 2922, 2855, 1593, 1351, 1119, 861, 765 cmꢁ1
;
1H NMR
(200 MHz, CDCl3):
d (ppm) 7.27 (s, 2H), 7.11 (s, 1H), 6.09 (br-s, 2H),
5.56 (br-s, 1H), 3.94 (s, 6H), 3.90 (s, 3H), 3.74–3.69 (m, 8H), 3.49–
3.46 (m, 4H), 2.69 (s, 3H), 2.54–2.43 (m, 12H). 13C NMR (50 MHz,
CDCl3): 172.35,166.53, 164.02, 163.01, 158.40, 153.82, 140.81,132.50,
107.86, 104.92, 67.28, 61.38, 57.67, 56.71, 53.76, 37.42, 12.94. Anal.
Calcd for C29H42N10O5S: C, 54.19; H, 6.59; N, 21.79. Found: C, 54.21;
H, 6.47; N, 21.63.
5.4.7. 4,6-Bis(4-methylpiperazin-1-yl)-N-(4-(methylthio)-6-(3,4,5-
trimethoxyphenyl)pyrimidin-2-yl)-1,3,5-triazin-2-amine (14)
Yield: 72%; mp 185–188 ꢂC; FAB-MS: 583 (M þ 1); IR (KBr):
3440, 3113, 2923, 2836, 1571, 1492, 1388, 1121, 1004, 819, 745 cmꢁ1
;
1H NMR (300 MHz, CDCl3):
d (ppm) 7.28 (s, 2H), 7.11 (s, 1H), 5.31
(br-s, 1H), 3.95 (s, 6H), 3.91 (s, 3H), 3.89–3.86 (m, 8H), 2.66 (s, 3H),
2.47–2.43 (m, 8H), 2.35 (s, 6H). 13C NMR (50 MHz, CDCl3): 170.27,
163.95, 162.44, 161.23, 156.66, 152.40, 139.26, 130.99, 107.44,104.82,
61.15, 56.43, 55.03, 46.12, 42.98, 12.23. Anal. Calcd for
C27H38N10O3S: C, 55.65; H, 6.57; N, 24.04. Found: C, 55.73; H, 6.49;
N, 24.11.
5.4.2. N2-(4-(Methylthio)-6-(3,4,5-trimethoxyphenyl)pyrimidin-2-
yl)-N4,N6-bis(3-morpholinopropyl)-1,3,5-triazine-2,4,6-triamine (9)
Yield: 65%; mp 135–137 ꢂC; FAB-MS: 671 (M þ 1); IR (KBr): 3401,
3260, 2931, 2853, 1575, 1475, 1348, 1126, 813, 759 cmꢁ1 1H NMR
;
(200 MHz, CDCl3):
d (ppm) 7.30 (s, 2H), 7.13 (s, 1H), 6.46 (br-s, 2H),
5.67 (br-s, 1H), 3.96 (s, 6H), 3.92 (s, 3H), 3.75–3.70 (m, 8H), 3.49–
3.44 (m, 4H), 2.65 (s, 3H), 2.48–2.36 (m, 12H), 1.76 (m, 4H). 13C NMR
(50 MHz, CDCl3): 172.55, 167.76, 165.39, 163.05, 157.97, 153.79,
140.78, 132.39, 108.14, 104.87, 67.27, 61.35, 57.02, 56.62, 54.02,
39.85, 26.31, 13.07. Anal. Calcd for C31H46N10O5S: C, 55.50; H, 6.91;
N, 20.88. Found: C, 55.37; H, 7.02; N, 20.79.
5.4.8. N2-(4-(Methylthio)-6-(3,4,5-trimethoxyphenyl)pyrimidin-2-
yl)-N4,N6-dipropyl-1,3,5-triazine-2,4,6-triamine (15)
Yield: 67%; mp 155–158 ꢂC; FAB-MS: 501 (M þ 1); IR (KBr):
3269, 2961, 2872, 1599, 1460, 1328, 1126, 813, 755 cmꢁ1 1H NMR
;
(200 MHz, CDCl3):
d (ppm) 7.25 (s, 2H), 7.09 (s, 1H), 5.89 (br-s, 2H),
5.13 (br-s, 1H), 3.94 (s, 6H), 3.91 (s, 3H), 3.28 (m, 4H), 2.68 (s, 3H),
1.50 (m, 4H), 0.89 (m, 6H). 13C NMR (50 MHz, CDCl3): 170.80,
164.89, 162.28, 161.70, 157.12, 152.10, 138.91, 131.15, 107.36, 104.58,
60.94, 56.25, 42.52, 22.79, 12.61, 11.43. Anal. Calcd for C23H32N8O3S:
C, 55.18; H, 6.44; N, 22.38. Found: C, 55.27; H, 6.39; N, 22.16.
5.4.3. N2,N4-Bis(2-(diethylamino)ethyl)-N6-(4-(methylthio)-6-
(3,4,5-trimethoxyphenyl)pyrimidin-2-yl)-1,3,5-triazine-2,4,6-
triamine (10)
Yield: 57%; mp 105–108 ꢂC; FAB-MS: 615 (M þ 1); IR (KBr):
3406, 2934, 2850, 1595, 1349, 1125, 762 cmꢁ1 1H NMR (200 MHz,
;
CDCl3):
d
(ppm) 7.26 (s, 2H), 7.10 (s, 1H), 6.07 (br-s, 2H), 5.64 (br-s,
5.4.9. N-(4-(Methylthio)-6-(3,4,5-trimethoxyphenyl)pyrimidin-
2-yl)-4,6-dimorpholino-1,3,5-triazin-2-amine (16)
1H), 3.94 (s, 6H), 3.89 (s, 3H), 3.45 (m, 4H), 2.69 (s, 3H), 2.60–2.50
(m,12H),1.01 (t,12H, J ¼ 7.08 Hz). 13C NMR (50 MHz, CDCl3): 172.32,
166.60, 163.96, 163.01, 158.50, 153.77, 140.66, 132.59, 107.81, 104.84,
61.34, 56.66, 52.06, 47.16, 38.59, 12.96, 11.85. Anal. Calcd for
C29H46N10O3S: C, 56.65; H, 7.54; N, 22.78. Found: C, 56.58; H, 7.47;
N, 22.61.
Yield: 69%; mp 161–163 ꢂC; FAB-MS: 557 (M þ 1); IR (KBr):
3427, 2925, 2851, 1600, 1480, 1422, 1326, 1252, 1005, 855 cmꢁ1; 1H
NMR (200 MHz, CDCl3): d (ppm) 7.25 (s, 2H), 7.11 (s, 1H), 5.37 (br-s,
1H), 3.94 (s, 6H), 3.90 (s, 3H), 3.84 (m, 8H), 3.74–3.72 (m, 8H), 2.63
(s, 3H). 13C NMR (50 MHz, CDCl3): 172.08, 165.75, 164.14, 162.97,
158.27, 153.82, 141.13, 132.58, 107.98, 105.30, 67.17, 61.34, 56.89,
44.07,12.74. Anal. Calcd for C25H32N8O5S: C, 53.94; H, 5.79; N, 20.13.
Found: C, 53.77; H, 5.89; N, 20.15.
5.4.4. N2,N4-Dibutyl-N6-(4-(methylthio)-6-(3,4,5-
trimethoxyphenyl)pyrimidin-2-yl)-1,3,5-triazine-2,4,6-triamine (11)
Yield: 70%; mp 125–127 ꢂC; FAB-MS: 529 (M þ 1); IR (KBr):
3406, 2957, 2861, 1593, 1349, 1124, 818, 755 cmꢁ1
;
1H NMR
5.4.10. N2,N4-Diisopropyl-N6-(4-(methylthio)-6-(3,4,5-
(200 MHz, CDCl3):
d
(ppm) 7.20 (s, 2H), 7.07 (s, 1H), 5.97 (br-s, 2H),
trimethoxyphenyl)pyrimidin-2-yl)-1,3,5-triazine-2,4,6-triamine (17)
Yield: 71%; mp 128–130 ꢂC; FAB-MS: 501 (M þ 1); IR (KBr):
5.13 (br-s, 1H), 3.92 (s, 6H), 3.90 (s, 3H), 3.26 (m, 4H), 2.67 (s, 3H),
1.33–1.25 (m, 8H), 0.88–0.85 (m, 6H). 13C NMR (50 MHz, CDCl3):
172.46, 166.56, 163.99, 163.40, 158.86, 156.78, 140.53, 132.87, 107.79,
104.94, 61.32, 56.63, 40.84, 32.06, 20.43, 14.18, 13.01. Anal. Calcd for
C25H36N8O3S: C, 56.80; H, 6.86; N, 21.20. Found: C, 56.97; H, 6.62; N,
21.11.
3272, 2968, 2931, 1569, 1399, 1328, 1124, 1004, 814, 727 cmꢁ1 1H
;
NMR (200 MHz, CDCl3): d (ppm) 7.29 (s, 2H), 7.10 (s, 1H), 5.41 (br-s,
1H), 4.93 (br-s, 2H), 3.95 (s, 6H), 3.90 (s, 3H), 3.49–3.46 (m, 2H),
2.65 (s, 3H), 1.24–1.16 (m, 12H). 13C NMR (50 MHz, CDCl3): 172.34,
165.79, 163.77, 162.98, 158.53, 153.75, 140.78, 132.61, 107.53, 104.97,
61.33, 56.62, 42.81, 23.04, 12.97. Anal. Calcd for C23H32N8O3S: C,
55.18; H, 6.44; N, 22.38. Found: C, 55.04; H, 6.58; N, 22.29.
5.4.5. N2,N4-Di-tert-butyl-N6-(4-(methylthio)-6-(3,4,5-
trimethoxyphenyl)pyrimidin-2-yl)-1,3,5-triazine-2,4,6-triamine (12)
Yield: 78%; mp 109–111 ꢂC; FAB-MS: 529 (M þ 1); IR (KBr):
5.4.11. 4,6-Bis(4-ethylpiperazin-1-yl)-N-(4-(methylthio)-6-(3,4,5-
trimethoxyphenyl)pyrimidin-2-yl)-1,3,5-triazin-2-amine (18)
Yield: 69%; mp 168–170 ꢂC; FAB-MS: 611 (M þ 1); IR (KBr):
3405, 2959, 2856, 1597, 1363, 1114, 816, 761 cmꢁ1
;
1H NMR
(300 MHz, CDCl3):
d (ppm) 7.31 (s, 2H), 7.17 (s, 1H), 5.63 (br-s, 1H),
5.50 (br-s, 2H) 3.99 (s, 6H), 3.92 (s, 3H), 2.67 (s, 3H), 1.47 (s, 18H). 13C
NMR (75 MHz, CDCl3): 174.31, 166.68, 165.25, 164.49, 158.36, 155.11,
3408, 2967, 2860, 1596, 1414, 1389, 1118, 844, 765 cmꢁ1 1H NMR
;
(200 MHz, CDCl3):
d (ppm) 7.25 (s, 2H), 7.10 (s, 1H), 5.39 (br-s, 1H),

N. Sunduru et al. / European Journal of Medicinal Chemistry 44 (2009) 2473–2481
2479
3.94 (s, 6H), 3.90 (m, 11H), 2.65 (s, 3H), 2.48–2.45 (m, 12H), 1.12 (t,
5.4.17. N-(4-(3,4-Dimethoxyphenyl)-6-(methylthio)pyrimidin-2-
yl)-4,6-di(piperidin-1-yl)-1,3,5-triazin-2-amine (24)
6H, J ¼ 7.03 Hz). 13C NMR (50 MHz, CDCl3): 171.94, 165.56, 164.13,
162.91, 158.36, 153.79, 140.95, 132.68, 107.98, 105.12, 61.35, 56.85,
53.04, 52.81, 43.43, 12.73, 12.28. Anal. Calcd for C29H42N10O3S: C,
57.03; H, 6.93; N, 22.93. Found: C, 56.97; H, 6.82; N, 22.75.
Yield: 68%; mp 174–176 ꢂC; FAB-MS: 523 (M þ 1); IR (KBr): 3276,
2927, 2851, 1582, 1478, 1328, 1130, 1021, 802, 757 cmꢁ1 1H NMR
;
(200 MHz, CDCl3):
d (ppm) 7.61 (m, 2H), 7.10 (s, 1H), 6.90 (d, 1H,
J ¼ 8.46 Hz), 5.36 (br-s, 1H), 3.97 (s, 3H), 3.94 (s, 3H), 3.82–3.80 (m,
8H), 2.63 (s, 3H), 1.67–1.60 (m, 12H). 13C NMR (50 MHz, CDCl3):
171.54, 165.59, 164.15, 162.71, 158.50, 151.68, 149.46, 130.04, 120.86,
111.18, 110.48, 107.31, 56.56, 44.56, 26.25, 25.35, 12.71. Anal. Calcd
for C26H34N8O2S: C, 59.75; H, 6.56; N, 21.44. Found: C, 59.91; H,
6.52; N, 21.28.
5.4.12. N2-(4-(3,4-Dimethoxyphenyl)-6-(methylthio)pyrimidin-2-
yl)-N4,N6-bis(2-morpholinoethyl)-1,3,5-triazine-2,4,6-triamine (19)
Yield: 62%; mp 102–104 ꢂC; FAB-MS: 613 (M þ 1); IR (KBr):
3468, 2964, 2821, 1592, 1459, 1350, 1114, 764 cmꢁ1 1H NMR
;
(200 MHz, 95% CDCl3 þ 5% CD3OD):
d (ppm) 7.63 (m, 2H), 7.14 (s,
1H), 6.94 (d, 1H, J ¼ 8.50 Hz), 3.96 (s, 3H), 3.94 (s, 3H), 3.57–3.50 (m,
4H), 2.65 (s, 3H), 2.55 (m, 4H), 2.49 (m, 8H). 13C NMR (50 MHz, 95%
CDCl3 þ 5% CD3OD): 176.34, 170.19, 167.07, 162.03, 160.05, 155.77,
153.43, 133.64, 124.83, 115.32, 114.61,111.30, 71.02, 61.67, 60.24,
59.70, 57.65, 16.88. Anal. Calcd for C28H40N10O4S: C, 54.88; H, 6.58;
N, 22.86. Found: C, 54.62; H, 6.44; N, 22.79.
5.4.18. N-(4-(3,4-Dimethoxyphenyl)-6-(methylthio)pyrimidin-2-
yl)-4,6-bis(4-methylpiperazin-1-yl)-1,3,5-triazin-2-amine (25)
Yield: 71%; mp 105–108 ꢂC; FAB-MS: 553 (M þ 1); IR (KBr):
3431, 2927, 2853, 2797, 1591, 1514, 1347, 1142, 1003, 807, 763 cmꢁ1
;
1H NMR (200 MHz, CDCl3):
d (ppm) 7.64 (m, 2H), 7.14 (s, 1H), 6.94
(d, 1H, J ¼ 8.39 Hz), 5.33 (br-s, 1H), 3.96 (s, 3H), 3.94 (s, 3H), 3.92–
3.89 (m, 8H), 2.61 (s, 3H), 2.49 (m, 8H), 2.35 (s, 6H). 13C NMR
(50 MHz, CDCl3): 176.00, 169.46, 168.15, 166.82, 162.16, 155.81,
153.41, 133.71, 124.95, 115.28, 114.74, 111.31, 60.52, 58.98, 50.10,
47.01, 16.65. Anal. Calcd for C26H36N10O2S: C, 56.50; H, 6.57; N,
25.34. Found: C, 56.43; H, 6.54; N, 25.29.
5.4.13. N2-(4-(3,4-Dimethoxyphenyl)-6-(methylthio)pyrimidin-2-
yl)-N4,N6-bis(3-morpholinopropyl)-1,3,5-triazine-2,4,6-triamine (20)
Yield: 64%; mp 115–118 ꢂC; FAB-MS: 641 (M þ 1); IR (KBr): 3282,
2933, 2847,1594,1400,1348,1114, 810, 762 cmꢁ1; 1H NMR (200 MHz,
95% CDCl3 þ 5% CD3OD):
d (ppm) 7.62 (m, 2H), 7.13 (s,1H), 6.95 (d,1H,
J ¼ 8.51 Hz), 3.97 (s, 3H), 3.94 (s, 3H), 3.74 (t, 8H, J ¼ 4.07 Hz), 3.57 (m,
4H), 2.64 (s, 3H), 2.48 (m, 12H), 1.77 (m, 4H). 13C NMR (50 MHz, 95%
CDCl3 þ 5% CD3OD): 172.54, 166.32, 163.28, 161.54, 158.19, 151.73,
149.43,129.67,120.83,111.30,110.58,107.20,66.91, 56.86,56.30,53.80,
39.33, 26.19,13.05. Anal. Calcd for C30H44N10O4S: C, 56.23; H, 6.92; N,
21.86. Found: C, 56.09; H, 6.94; N, 21.98.
5.4.19. N2-(4-(3,4-Dimethoxyphenyl)-6-(methylthio)pyrimidin-2-
yl)-N4,N6-dipropyl-1,3,5-triazine-2,4,6-triamine (26)
Yield: 66%; mp 155–157 ꢂC; FAB-MS: 471 (M þ 1); IR (KBr):
3264, 2958, 2853, 1546, 1401, 1354, 1141, 1027, 835, 763 cmꢁ1 1H
;
NMR (200 MHz, CDCl3):
d (ppm) 7.62 (m, 2H), 7.09 (s, 1H), 6.92 (d,
1H, J ¼ 8.49 Hz), 5.98 (br-s, 2H), 5.11 (br-s, 1H), 3.95 (s, 3H), 3.94 (s,
3H), 3.46–3.27 (m, 4H), 2.65 (s, 3H), 1.49 (m, 4H), 0.89–0.85 (m, 6H).
13C NMR (50 MHz, CDCl3): 172.53, 166.07, 165.84, 164.29, 158.24,
151.89, 149.32, 131.43, 120.75, 111.20, 110.54, 107.23, 56.39, 42.93,
23.24, 13.04, 11.86. Anal. Calcd for C22H30N8O2S: C, 56.15; H, 6.43; N,
23.81. Found: C, 56.07; H, 6.41; N, 23.79.
5.4.14. N2,N4-Bis(2-(diethylamino)ethyl)-N6-(4-(3,4-
dimethoxyphenyl)-6-(methylthio)pyrimidin-2-yl)-1,3,5-triazine-
2,4,6-triamine (21)
Yield: 68%; mp 125–127 ꢂC; FAB-MS: 585 (M þ 1); IR (KBr):
3278, 2967, 2930, 1568, 1403, 1341, 1303, 1138, 812, 760 cmꢁ1 1H
;
NMR (200 MHz, CDCl3):
d (ppm) 7.60 (m, 2H), 7.09 (s, 1H), 6.91 (d,
1H, J ¼ 8.53 Hz), 6.32 (br-s, 2H), 5.68 (br-s, 1H), 3.95 (s, 3H), 3.93 (s,
3H), 3.40 (m, 4H), 2.66 (s, 3H), 2.53–2.50 (m, 12H), 0.99 (t, 12H,
J ¼ 7.05 Hz). 13C NMR (50 MHz, CDCl3): 171.98, 166.63, 164.01,
162.98, 158.61, 151.65, 149.47, 129.87, 120.76, 111.24, 110.49, 107.22,
56.32, 52.11, 47.18, 38.70, 11.99, 11.34. Anal. Calcd for C28H44N10O2S:
C, 57.51; H, 7.58; N, 23.95. Found: C, 57.72; H, 7.55; N, 24.03.
5.4.20. N-(4-(3,4-Dimethoxyphenyl)-6-(methylthio)pyrimidin-2-
yl)-4,6-dimorpholino-1,3,5-triazin-2-amine (27)
Yield: 70%; mp 185–188 ꢂC; FAB-MS: 527 (M þ 1); IR (KBr): 3426,
2953, 2841, 1593, 1478, 1350, 1111, 1023, 805, 769 cmꢁ1 1H NMR
;
(200 MHz, CDCl3):
d (ppm) 7.68 (m, 2H), 7.12 (s, 1H), 6.90 (d, 1H,
J ¼ 8.47 Hz), 5.35 (br-s, 1H), 3.96 (s, 3H), 3.94 (s, 3H), 3.85–3.82 (m,
8H), 3.75–3.70 (m, 8H), 2.60 (s, 3H).13C NMR (50 MHz, CDCl3): 171.84,
165.78, 164.14, 162.88, 158.21, 151.89, 149.52, 129.85, 120.92, 111.15,
110.64,107.45, 67.22, 56.64, 44.08,12.81. Anal. Calcd for C24H30N8O4S:
C, 54.74; H, 5.74; N, 21.28. Found: C, 54.51; H, 5.69; N, 21.42.
5.4.15. N2,N4-Dibutyl-N6-(4-(3,4-dimethoxyphenyl)-6-
(methylthio)pyrimidin-2-yl)-1,3,5-triazine-2,4,6-triamine (22)
Yield: 79%; mp 138–140 ꢂC; FAB-MS: 499 (M þ 1); IR (KBr):
3275, 2931, 2853, 1576, 1401, 1347, 1136, 1022, 810, 759 cmꢁ1 1H
;
NMR (200 MHz, CDCl3):
d
(ppm) 7.60 (m, 2H), 7.08 (s, 1H), 6.92 (d,
5.4.21. N2-(4-(3,4-Dimethoxyphenyl)-6-(methylthio)pyrimidin-2-
yl)-N4,N6-diisopropyl-1,3,5-triazine-2,4,6-triamine (28)
1H, J ¼ 8.47 Hz), 6.07 (br-s, 2H), 5.12 (br-s, 1H), 3.96 (s, 3H), 3.94 (s,
3H), 3.28 (m, 4H), 2.65 (s, 3H), 1.39–1.25 (m, 8H), 0.89–0.85 (m, 6H).
13C NMR (50 MHz, CDCl3): 172.14, 166.54, 163.89, 163.31, 158.78,
151.57, 149.47, 130.08, 120.76, 111.23, 110.59, 107.30, 56.36, 40.85,
32.10, 20.44, 14.19, 13.03. Anal. Calcd for C24H34N8O2S: C, 57.81; H,
6.87; N, 22.47. Found: C, 57.69; H, 6.76; N, 22.43.
Yield: 70%; mp 141–143 ꢂC; FAB-MS: 471 (M þ 1); IR (KBr): 3310,
2946, 2853, 1583, 1439, 1347, 1327, 1130, 1015, 815, 753 cmꢁ1 1H
;
NMR (200 MHz, CDCl3):
d (ppm) 7.58 (m, 2H), 7.08 (s, 1H), 6.91 (d,
1H, J ¼ 8.13 Hz), 5.52 (br-s, 1H), 5.07 (br-s, 2H), 3.94 (s, 3H), 3.92 (s,
3H), 3.48–3.46 (m, 2H), 2.66 (s, 3H), 1.24–1.14 (m, 12H). 13C NMR
(50 MHz, CDCl3): 172.19, 165.73, 163.54, 162.78, 158.51, 153.72,
140.77, 132.66, 111.23, 107.31, 56.78, 42.76, 23.28, 13.08. Anal. Calcd
for C22H30N8O2S: C, 56.15; H, 6.43; N, 23.81. Found: C, 56.32; H,
6.39; N, 23.86.
5.4.16. N2,N4-Di-tert-butyl-N6-(4-(3,4-dimethoxyphenyl)-6-
(methylthio)pyrimidin-2-yl)-1,3,5-triazine-2,4,6-triamine (23)
Yield: 74%; mp 100–102 ꢂC; FAB-MS: 499 (M þ 1); IR (KBr):
3393, 2962, 2854, 1589, 1402, 1347, 1152, 1020, 805, 763 cmꢁ1 1H
;
NMR (200 MHz, CDCl3):
d
(ppm) 7.76 (m, 2H), 7.21 (s, 1H), 6.93 (d,
5.4.22. N-(4-(3,4-Dimethoxyphenyl)-6-(methylthio)pyrimidin-2-
yl)-4,6-bis(4-ethylpiperazin-1-yl)-1,3,5-triazin-2-amine (29)
Yield: 68%; mp 164–166 ꢂC; FAB-MS: 581 (M þ 1); IR (KBr):
1H, J ¼ 8.46 Hz), 5.64 (br-s, 1H), 5.48 (br-s, 2H), 4.02 (s, 3H), 3.95 (s,
3H), 2.64 (s, 3H), 1.45 (s, 18H). 13C NMR (50 MHz, CDCl3): 172.57,
166.11, 163.98, 163.18, 157.05, 151.91, 149.61, 129.42, 120.62, 111.17,
110.49, 108.18, 56.39, 29.02, 13.15. Anal. Calcd for C24H34N8O2S: C,
57.81; H, 6.87; N, 22.47. Found: C, 57.74; H, 6.92; N, 22.56.
3428, 2966, 2814, 1563, 1444, 1395, 1253, 1161, 1013, 810, 760 cmꢁ1
;
1H NMR (200 MHz, CDCl3):
6.94 (d, 1H, J ¼ 8.43 Hz), 5.38 (br-s, 1H), 3.97 (s, 3H), 3.94 (s, 3H),
d (ppm) 7.69 (m, 2H), 7.14 (s, 1H),

2480
N. Sunduru et al. / European Journal of Medicinal Chemistry 44 (2009) 2473–2481
3.91–3.89 (m, 8H), 2.63 (s, 3H), 2.53–2.43 (m, 12H), 1.24–1.10 (m,
6H). 13C NMR (50 MHz, CDCl3): 175.97, 169.41, 168.05, 166.86,
162.10, 155.75, 153.40, 133.79, 124.91, 115.21, 114.64, 111.37, 60.50,
56.84, 56.69, 47.09, 16.68, 15.75. Anal. Calcd for C28H40N10O2S: C,
57.91; H, 6.94; N, 24.12. Found: C, 57.63; H, 7.12; N, 24.09.
5.6.3. N4-(2-(Diethylamino)ethyl)-6-(3,4,5-
trimethoxyphenyl)pyrimidine-2,4-diamine (32)
Yield: 64%; mp 143–145 ꢂC; FAB-MS: 376 (M þ 1); IR (KBr):
3410, 3356, 3204, 2968, 2829, 1650, 1577, 1508, 1470, 1375, 1206,
1125, 860, 808 cmꢁ1 1H NMR (200 MHz, CDCl3):
; d (ppm) 7.15 (s,
2H), 6.12 (s, 1H), 5.52 (s, 1H), 4.85 (br-s, 2H), 3.93 (s, 6H), 3.88 (s,
3H), 3.41–3.38 (m, 2H), 2.71–2.53 (m, 6H), 1.04 (t, 6H, J ¼ 7.12 Hz).
13C NMR (50 MHz, CDCl3): 164.53, 164.05, 163.47, 153.62, 139.82,
134.47, 104.48, 91.56, 61.30, 56.62, 51.76, 47.01, 38.94, 11.90. Anal.
Calcd for C19H29N5O3: C, 60.78; H, 7.79; N, 18.65. Found: C, 60.69; H,
7.72; N, 18.57.
5.5. General procedure for the synthesis of compound 7
To an ice-cold solution of compound 3 (1 equiv) in dry DCM was
added m-CPBA (2.5 equiv) solution in dry DCM through dropping
funnel for 30 min, after the addition of m-CPBA, the reaction
mixture was left to stir at r.t. for 1 h. After stirring a saturated
solution of NaHCO3 was added to the reaction mixture and allowed
to stir vigorously for 30 min. The organic layer was separated and
washed twice with water and dried over anhydrous Na2SO4. The
solution was concentrated and purified with column chromatog-
raphy to afford compound 7 in the range of 72–75%.
5.6.4. N4-Butyl-6-(3,4,5-trimethoxyphenyl)pyrimidine-
2,4-diamine (33)
Yield: 72%; mp 135–137 ꢂC; FAB-MS: 333 (M þ 1); IR (KBr):
3432, 3317, 3215, 2958, 2868, 1648, 1580, 1458, 1387, 1316, 1229,
1129, 856, 801 cmꢁ1 1H NMR (300 MHz, CDCl3):
; d (ppm) 7.16
(s, 2H), 6.11 (s, 1H), 5.09 (s, 1H), 4.93 (br-s, 2H), 3.96 (s, 6H), 3.93
(s, 3H), 3.39–3.33 (m, 2H), 1.67–1.58 (m, 2H), 1.51–1.38 (m, 2H), 0.98
(t, 3H, J ¼ 7.53 Hz). 13C NMR (75 MHz, CDCl3): 162.87,162.22,160.98,
152.02, 138.45, 133.10, 102.87, 89.78, 59.66, 55.02, 39.89, 30.24,
18.81, 12.53. Anal. Calcd for C17H24N4O3: C, 61.43; H, 7.28; N, 16.86.
Found: C, 61.52; H, 7.23; N, 16.81.
5.5.1. 4-(Methylsulfonyl)-6-(3,4,5-trimethoxyphenyl)pyrimidin-2-
amine (7)
Yield: 73%; mp 126–128 ꢂC; FAB-MS: 340 (M þ 1); IR (KBr):
3438, 3326, 3208, 3052, 2934, 1638, 1562, 1434, 1347, 1226, 1125,
1004, 816 cmꢁ1; 1H NMR (200 MHz, CDCl3): 7.18 (s, 2H), 6.86 (s,1H),
5.06 (br-s, 2H), 3.96 (s, 6H), 3.90 (s, 3H), 3.21 (s, 3H). 13C NMR
(75 MHz, CDCl3): 171.62, 162.97, 162.38, 153.35, 140.04, 132.67,
104.58, 104.26, 60.98, 56.32, 38.63. Anal. Calcd for C14H17N3O5S: C,
49.55; H, 5.05; N, 12.38. Found: C, 49.61; H, 5.02; N, 12.35.
5.6.5. 4-(Piperidin-1-yl)-6-(3,4,5-trimethoxyphenyl)pyrimidin-2-
amine (34)
Yield: 68%; mp 134–136 ꢂC; FAB-MS: 345 (M þ 1); IR (KBr):
3474, 3349, 3193, 2933, 2853, 1629, 1572, 1506, 1409, 1329, 1284,
1124, 876, 797 cmꢁ1 1H NMR (300 MHz, CDCl3):
; d (ppm) 7.14
(s, 2H), 6.28 (s, 1H), 4.86 (br-s, 2H), 3.96 (s, 6H), 3.90 (s, 3H), 3.65
(t, 4H, J ¼ 4.56 Hz), 1.73–1.64 (m, 6H). 13C NMR (50 MHz, CDCl3):
164.52, 163.92, 163.12, 153.67, 139.98, 134.90, 104.77, 90.82, 61.30,
56.72, 45.59, 26.04, 25.13. Anal. Calcd for C18H24N4O3: C, 62.77; H,
7.02; N, 16.27. Found: C, 62.70; H, 6.94; N, 16.32.
5.6. General procedure for the synthesis of compounds 30–36
The solution of compound 7 (1 equiv) and different amines
(1 equiv) listed in Table 1 in dry THF was heated in closed steel
vessel at 100 ꢂC for 12 h. The solvent was removed under vacuum
and the resultant residue was dissolved in CHCl3 (100 ml). The
organic phase was washed with H2O (three times), dried over
anhydrous Na2SO4. The solution was concentrated and purified
with column chromatography to afford compounds 30–36 in good
yields.
5.6.6. 4-(4-Methylpiperazin-1-yl)-6-(3,4,5-
trimethoxyphenyl)pyrimidin-2-amine (35)
Yield: 73%; mp 149–151 ꢂC; FAB-MS: 360 (M þ 1); IR (KBr): 3477,
3305, 3187, 2933, 2841,1626,1573,1506,1406,1304,1235,1127, 867,
797 cmꢁ1 1H NMR (300 MHz, CDCl3):
; d (ppm) 7.14 (s, 2H), 6.27
(s, 1H), 4.89 (br-s, 2H), 3.95 (s, 6H), 3.89 (s, 3H), 3.69 (t, 4H,
J ¼ 4.52 Hz), 2.49 (t, 4H, J ¼ 4.46 Hz), 2.36 (s, 3H). 13C NMR (50 MHz,
CDCl3): 162.99, 162.24, 161.22, 151.73, 138.10, 132.82, 102.81, 88.81,
59.36, 54.77, 53.19, 44.59, 42.38. Anal. Calcd for C18H25N5O3: C,
60.15; H, 7.01; N, 19.48. Found: C, 60.18; H, 7.08; N, 19.43.
5.6.1. N4-(2-Morpholinoethyl)-6-(3,4,5-
trimethoxyphenyl)pyrimidine-2,4-diamine (30)
Yield: 67%; mp 179–181 ꢂC; FAB-MS: 390 (M þ 1); IR (KBr):
3405, 3328, 3185, 2928, 2849, 1659, 1574, 1466, 1377, 1260, 1119,
859, 805 cmꢁ1; 1H NMR (300 MHz, CDCl3):
d
(ppm) 7.16 (s, 2H), 6.13
5.6.7. 4-Morpholino-6-(3,4,5-trimethoxyphenyl)pyrimidin-
2-amine (36)
(s, 1H), 5.42 (s, 1H), 4.93 (br-s, 2H), 3.95 (s, 6H), 3.89 (s, 3H), 3.76–
3.71 (m, 4H), 3.48–3.41 (m, 2H), 2.62 (t, 2H, J ¼ 5.98 Hz), 2.48 (t, 4H,
J ¼ 7.52 Hz). 13C NMR (50 MHz, CDCl3): 164.43, 164.03, 163.35,
153.63,140.04,134.19,104.59, 91.61, 67.26, 61.28, 57.36, 56.64, 54.51,
53.71, 37.70. Anal. Calcd for C19H27N5O4: C, 58.60; H, 6.99; N, 17.98.
Found: C, 58.56; H, 6.92; N, 17.93.
Yield: 68%; mp 133–135 ꢂC; FAB-MS: 347 (M þ 1); IR (KBr):
3462, 3354, 3215, 2965, 2835, 1622, 1576, 1505, 1406, 1330, 1253,
1124, 882, 796 cmꢁ1 1H NMR (200 MHz, CDCl3):
; d (ppm) 7.12
(s, 2H), 6.24 (s, 1H), 4.84 (br-s, 2H), 3.94 (s, 6H), 3.88 (s, 3H), 3.79
(t, 4H, J ¼ 4.47 Hz), 3.64 (t, 4H, J ¼ 4.44 Hz). 13C NMR (50 MHz,
CDCl3): 165.33, 164.49, 163.23, 153.69, 140.06, 134.77, 104.68, 90.60,
67.03, 61.32, 56.69, 44.76. Anal. Calcd for C17H22N4O4: C, 58.95;
H, 6.40; N, 16.17. Found: C, 58.91; H, 6.47; N, 16.22.
5.6.2. N4-(3-Morpholinopropyl)-6-(3,4,5-
trimethoxyphenyl)pyrimidine-2,4-diamine (31)
Yield: 62%; mp 138–140 ꢂC; FAB-MS: 404 (M þ 1); IR (KBr):
3431, 3336, 3224, 2933, 2863, 1634, 1574, 1506, 1457, 1312, 1122,
Acknowledgement
861, 805 cmꢁ1; 1H NMR (300 MHz, CDCl3):
d (ppm) 7.14 (s, 2H), 6.07
(s, 1H), 5.76 (s, 1H), 4.91 (br-s, 2H), 3.94 (s, 6H), 3.89 (s, 3H), 3.75 (t,
4H, J ¼ 5.96 Hz), 3.48–3.42 (m, 2H), 2.49 (t, 6H, J ¼ 7.49 Hz), 1.84–
1.76 (m, 2H). 13C NMR (50 MHz, CDCl3): 164.66, 164.28, 163.48,
153.63, 140.02, 134.49, 104.64, 91.44, 67.40, 61.29, 57.52, 56.65,
54.13, 40.84, 25.93. Anal. Calcd for C20H29N5O4: C, 59.54; H, 7.24; N,
17.36. Found: C, 59.62; H, 7.19; N, 17.33.
N.S. thanks the Council of Scientific and Industrial Research
(India) for the award of Senior Research Fellowship. N.S. also
thanks L.G. We are also thankful to S.A.I.F. Division, CDRI, Lucknow
for providing spectroscopic data. Thanks are also due to Dr.
Neena Goyal, Scientist, Biochemistry Division, CDRI for providing
luciferase transfected parasites. CDRI communication No.: 7588.

N. Sunduru et al. / European Journal of Medicinal Chemistry 44 (2009) 2473–2481
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