Design, synthesis, characterization, and in vitro antimicrobial action of novel trisubstituted s-triazines

Article abstract of DOI:10.1007/s00044-011-9849-0

In this article, synthesis of a library of trisubstituted s-triazines, which, in addition to 4-amino-benzonitrile, contain 4-hydroxy-N-methylquinolin- 2(1H)-one as well as substituted aliphatic amines condensed to C-6 position of s-triazinyl core is discu

Full text of DOI:10.1007/s00044-011-9849-0

MEDICINAL
CHEMISTRY
RESEARCH
Med Chem Res (2012) 21:3182–3194
DOI 10.1007/s00044-011-9849-0
ORIGINAL RESEARCH
Design, synthesis, characterization, and in vitro antimicrobial
action of novel trisubstituted s-triazines
•
Paresh K. Patel Rahul V. Patel Dharmesh H. Mahajan
•
•
•
Parimal A. Parikh Girish N. Mehta Kishor H. Chikhalia
•
Received: 11 July 2011 / Accepted: 25 October 2011 / Published online: 12 November 2011
Ó Springer Science+Business Media, LLC 2011
Abstract In this article, synthesis of a library of trisub-
stituted s-triazines, which, in addition to 4-amino-benzo-
nitrile, contain 4-hydroxy-N-methylquinolin-2(1H)-one as
well as substituted aliphatic amines condensed to C-6
position of s-triazinyl core is discussed. The newly syn-
thesized analogues were then subjected to determine their
efficacy against some bacterial and fungal strains as two
gram-positive bacteria (Staphylococcus aureus MTCC 96
and Bacillus cereus MTCC 619), six gram-negative bac-
teria (Escherichia coli MTCC 739, Pseudomonas aeru-
ginosa MTCC 741, Klebsiella pneumoniae MTCC 109,
Salmonella typhi MTCC 733, Proteus vulgaris MTCC
1771, and Shigella flexneria MTCC 1457) and two fungal
species (Aspergillus niger MTCC 282 and Candida albi-
cans MTCC 183) with an intent to develop novel class of
antimicrobial agents. The results of bioassay showed that
some of the newly synthesized s-triazine congeners
emerged with noteworthy antimicrobial activity. The
structure of final scaffolds has been assigned on the basis of
1
IR, H NMR, 13C NMR, mass spectroscopy and elemental
analysis.
Keywords s-Triazine ꢀ Quinoline ꢀ Antimicrobial activity
Introduction
P. K. Patel ꢀ R. V. Patel ꢀ G. N. Mehta
Department of Applied Chemistry, Sardar Vallabhbhai National
Institute of Technology (SVNIT), Surat 395 007, Gujarat, India
e-mail: kruparesh@yahoo.com
A higher incidence of opportunistic microbial infections
caused by various bacteria and fungi due to the evolution
and spread of multidrug-resistant microorganisms has
become a widespread medical problem. Such infections
most commonly cause severe morbidity and mortality in
debilitated and immunocompromised patients (Chu et al.,
1996; Overbye and Barrett, 2005; Walsh, 2000). Many
research groups have been working to solve the antibacte-
rial resistance problems. One possible long-term solution is
in the development of agents that act on unexploited anti-
bacterial target (Niccolai et al., 1997). The s-triazine-based
derivatives demonstrate a wide range of biological activi-
ties. They are found to be effective as antibacterial (Srinivas
et al., 2006; Solankee et al., 2010; Patel et al., 2010a, b, c;
Zhou et al., 2008), antifungal (Mishra et al., 2000; Sareen
et al., 2006), antitubercular (Sunduru et al., 2010), anti-
malarial (Agarwal et al., 2005; Manohar et al., 2010),
anticancer (Menicagli et al., 2004; Saczewski et al., 2006;
Saczewski and Bulakowska, 2006), antiprotozoals (Baliani
R. V. Patel
e-mail: rahul.svnit.11@gmail.com
G. N. Mehta
e-mail: girish17in@yahoo.co.in
D. H. Mahajan
Department of Chemistry, KBS Commerce & NATARAJ
Professional Science College, Vapi 396 195, Gujarat, India
e-mail: mahajan_dh@yahoo.com
P. A. Parikh
Department of Chemical Engineering, Sardar Vallabhbhai
National Institute of Technology (SVNIT), Surat 395 007,
Gujarat, India
e-mail: parimal_svr@yahoo.co.uk
K. H. Chikhalia (&)
School of Science, Department of Chemistry, Gujarat
University, Ahmedabad 380 009, Gujarat, India
e-mail: chikhalia_kh@yahoo.com
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et al., 2005), estrogen receptor modulators (Rodriguez
et al., 2004), and anti-HIV(Xionga et al., 2009; Xionga
et al., 2008; Ludovici et al., 2001; Mahajan et al., 2009;
Patel et al., 2007). Derivatives of s-triazine have been used
in the treatment of depression (Whitten et al., 1996) and as
bridging agents to synthesize herbicides (Seffernick et al.,
2002). Further, substituted s-triazines have been used as
NLO materials, which have a wide range of applications in
optoelectronics and telecommunications (Thalladi et al.,
1998; Zhu and Wu, 2001). 2,4,6-trichloro-1,3,5-triazine is
an inexpensive, commercially available reagent, and the
different reactivities of the chlorine atoms, which are con-
trolled by temperature, make its use more attractive.
Quinolines are the effective moieties in a large number of
natural and synthetic heterocyclic compounds that exhibit
significant antibiotic activity found in the structure of many
well-known antimicrobial drugs like ciprofloxacin, nor-
floxacin, ofloxacin, pefloxacin, rufloxacin, enrofloxacin,
etc. In addition, condensations of substituted aromatic
amines to any pharmacophore play an important role
leading to the distinctive modification in their biological
profiles of the resultant systems. In the design of new
compounds, the developments of hybrid molecule through
the combination of different pharmacophores in one struc-
ture may lead to increased antimicrobial activity. These
observations prompted us to adopt the sequential intro-
duction of the substituted aliphatic amines to the s-triazine
core involving ethereal and amine linkages to the s-triazine
core by hydroxyl quinoline and aminobenzonitrile moieties,
respectively, to maintain a pool of new bioactive candidates
at all times.
Experimental
Materials and methods
2,4,6-Trichloro-1,3,5-triazine, 4-hydroxy-N-methylquino-
lin-2(1H)-one, and 4-amino-benzonitrile were purchased
from Sigma-Aldrich Germany. Used solvent acetone was
of laboratory grade purchased from Merck and Qualigens;
tetrahydrofuran was of AR grade, purchased from Merck,
used without further purification; and coupling-substituted
aliphatic amines were purchased from Merck, Qualigens,
Finar, National and Spectrochem. The melting points of the
products were determined in open capillaries using Veego
electronic apparatus (Model: VMP-D) and are uncorrected.
The IR spectra (4000–400 cm-1) of synthesized com-
pounds were recorded on Shimadzu 8400-S FT-IR spec-
trophotometer using KBr pellets. To monitor the reactions,
and to establish the purity of reactants and products, thin
layer chromatography was performed on microscopic glass
slides (2 9 7.5 cm) coated with silica gel-G, and spots
were visualized under UV radiation. 1H NMR and 13C
NMR spectra were recorded on Varian 400-MHz model
spectrometer using DMSO-d6 as a solvent and TMS as
1
internal standard with H resonant frequency of 400 MHz
and 13C resonant frequency of 100 MHz. The 1H NMR and
13C NMR chemical shifts were reported as d parts per
million (ppm) downfield from TMS (Me4Si). The splitting
patterns are designated as follows; s, singlet; d, doublet;
and m, multiplet. The mass spectra were recorded on JOEL
SX-102 (EI) model. Elemental analyses (C, H, and N) were
performed using Heraeus Carlo Erba 1180 CHN analyzer
(Hanau, Germany).
Recently, our research group has reported antimicrobial
activities of a series of new s-triazine-based analogues
involving substitutions of 4-amino-benzonitrile and
8-hydroxyquinoline (Patel et al., 2010a, b, c), 4-amino-
benzonitrile, and 4-hydroxy-N-methylquinolin-2(1H)-one
(Patel et al., 2011a, b), as well as simple aniline and
4-hydroxycoumarin (Patel et al., 2011a, b). It is suffice to
mention here that we introduced piperazine or piperidine
derivatives in all the cases that our previous study inves-
tigated and the compounds have shown promising antimi-
crobial activities, representing a promising lead for further
optimization. To extend their structure–activity relation-
ships (SARs), we have designed and synthesized a novel
series based on the modification of a piperazinyl or pipe-
ridinyl structural unit to simple aliphatic amines. We have
introduced the similar 4-amino-benzonitrile and
4-hydroxy-N-methylquinolin-2(1H)-one in this study to
identify the differences between the biological profiles of
the resultant series, in which activity was found to be
increased significantly against most of the studied strains of
bacteria and fungi in terms of MIC as well as inhibition
zones.
Synthesis of 4-(4,6-dichloro-1,3,5-triazin-2-
ylammino)benzonitrile (3)
Mixture of 2,4,6-trichloro-1,3,5-triazine chloride 1 (1.85 g,
0.01 mol) and anhydrous potassium carbonate (K2CO3)
(1.38 g, 0.01 mol) in 25 ml acetone was stirred at 0–5°C
for 20 min. 4-amino-benzonitrile 2 (1.84 g, 0.01 mol) was
added portion wise at the same temperature to the above
mixture; after complete addition, the reaction mixture was
stirred for 4–5 h at the same temperature. Progress of the
reaction was monitored by TLC using toluene/acetone (8:2,
v/v) solvent system as an eluent. After completion of the
reaction, resultant mixture was poured on crushed ice. The
solid product obtained was filtered, washed with distilled
water, dried, and purified by column chromatography using
toluene/acetone solvent system as an eluent. Yield: 90%;
m.p. [300°C (dec.); IR KBr cm: 3277 (N–H), 2228
(C:N), 833 (C3N3, s-triazine); 1H NMR (400 MHz,
DMSO-d6): d 11.50 (s, 1H, –NH proton of s-triazine to
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Med Chem Res (2012) 21:3182–3194
aminobenzonitrile linkage), 7.86–7.78 (m, 4H, Ar–H aro-
matic proton); 13C NMR (100 MHz, DMSO-d6): d 173.81
(2C, C–Cl of s-triazine), 164.37 (1C, C–NH of s-triazine to
aminobenzonitrile linkage), 141.99–119.32 (6C, Ar–C of
aromatic), 106.84 (1C, –C:N of aminobenzonitrile moiety).
product was obtained, filtered, washed with distilled water,
and dried and purified by column chromatography using
toluene/acetone solvent system as an eluent.
4-(4-(1-Methyl-2-oxo-1,2-dihydroquinolin-4-yloxy)-6-
(methylamino)-1,3,5-triazin-2-ylamino)benzonitrile
(6a)
Synthesis of 4-(4-chloro-6-(1-methyl-2-oxo-1,2-
dihydroquinilin-4-yloxy)-1,3,5-triazin-2-ylamino)-
benzonitrile (5)
Yield: 82%; m.p. 166°C; IR (KBr cm-1): 3271 (N–H),
2909 (C–H in N–CH3), 2222 (C:N), 1647 (C=O), 1305
(C–N in 2o aromatic amine), 1246 (C–O–C), 1109 (C–N
in aliphatic amine), 833 (C3N3 s-triazine); 1H NMR
(400 MHz, DMSO-d6): d 10.22 (s, 1H, –NH of amino-
benzonitrile linkage), 9.99 (s, 1H, –NH–CH3 of methyl
amine), 8.04–7.28 (m, 8H, Ar. –H), 6.59 (s, 1H, –CH–
(C=O)–N of quinoline), 3.67 (s, 3H, –N–CH3 of quinoline);
3.67 (s, 3H, –N–CH3 of methyl amine); 13C NMR
(100 MHz, DMSO-d6): d 174.12 (1C, –C–NH–CH3, of
s-triazine to methyl amine) 172.68 (1C, –C–O–C, s-triazine
to 4-HMQ linkage), 168.28 (1C, –C–NH of aminobenzo-
nitrile), 163.38 (1C, –C=O of quinoline), 159.21 (1C, –C–
O–C, 4-HMQ linkage to s-triazine) 151.86–115.99 (12C,
–Ar. C atoms), 104.91 (1C, –CN), 101.95 (1C, –C–(C=O)–
N of quinoline), 32.19 (1C, –N–CH3 of quinoline), 26.12
(1C, –NH–CH3 of methyl amine); Anal. Calcd. For
C21H17N7O2: C, 63.15; H, 4.29; N, 24.55% Found: C,
63.09; H, 4.20; N, 24.63%; ESI–MS (m/z): 400.38 (M?,
100%).
Mixture of 4-hydroxy-N-methylquinolin-2(1H)-one
4
(1.75 g, 0.01 mol) and anhydrous potassium carbonate
(K2CO3) (1.38 g, 0.01 mol) in 50 ml acetone was stirred at
room temperature for 30 min. Then, compound 3 (2.66 g,
0.01 mol) was added portion wise at room temperature
with stirring; after complete addition, the reaction mixture
was stirred 6–7 h at 40–45°C in water bath. Progress of the
reaction was monitored by TLC using toluene/acetone (7:3,
v/v) solvent system as an eluent. After completion of the
reaction, resultant mixture was poured on crushed ice. The
solid product was obtained, filtered, washed with distilled
water, dried, and purified by column chromatography using
toluene/acetone solvent system as an eluent. Yield: 88%;
m.p. 243–246°C; IR KBr cm: 3281 (N–H), 2225 (C:N),
831(C3N3, s-triazine); 1256 (C–O–C); 1H NMR (400 MHz,
DMSO-d6) d 11.25 (s, 1H, –NH proton of s-triazine to
aminobenzonitrile linkage), 7.78–7.25 (m, 8H, Ar–H aro-
matic proton), 6.71 (s, 1H, –CH–(C=O)–N proton of
quinoline moiety), 3.66 (s, 3H, –N–CH3 proton of quino-
line moiety); 13C NMR (100 MHz, DMSO-d6) d 175.78
(1C, C–Cl of s-triazine), 170.45 (1C, C–O–C, of s-triazine
to 4-HMQ linkage), 169.71 (1C, C–NH of s-triazine to
aminobenzonitrile linkage), 160.69 (1C, –C=O of quinoline
moiety), 143.40–127.63 (13C, Ar–C of aromatic), 105.94
(1C, –C:N of aminobenzonitrile moiety), 102.92 (1C,
–C–(C=O)–N of quinoline moiety), 29.76 (1C, –N–CH3 of
quinoline moiety); ESI–MS (m/z): 404.95 (M?, 100).
4-(4-(Dimethylamino)-6-(1-methyl-2-oxo-1,2-
dihydroquinolin-4-yloxy)-1,3,5-triazin-2-
ylamino)benzonitrile (6b)
Yield: 81%; m.p. 248–249°C; IR (KBr cm-1): 3274 (N–H),
2890 (C–H in N–CH3), 2224 (C:N), 1654 (C=O), 1309
(C–N in 2o aromatic amine), 1249 (C–O–C), 1121 (C–N
in aliphatic amine), 830 (C3N3 s-triazine); 1H NMR
(400 MHz, DMSO-d6): d 10.29 (s, 1H, –NH of amino-
benzonitrile linkage), 8.18–7.32 (m, 8H, Ar. –H), 6.42 (s,
1H, –CH–(C=O)–N of quinoline), 3.60 (s, 3H, –N–CH3 of
quinoline); 3.06 (s, 6H, –N–(CH3)2 of dimethyl amine);
13C NMR (100 MHz, DMSO-d6): d 175.21 (1C, –C–O–C,
s-triazine to 4-HMQ linkage), 171.85 (1C, –C–N(CH3)2, of
s-triazine to dimethyl amine), 166.58 (1C, –C–NH of
aminobenzonitrile), 162.88 (1C, –C=O of quinoline),
156.11 (1C, –C–O–C, 4-HMQ linkage to s-triazine)
147.09–114.12 (12C, –Ar. C atoms), 104.25 (1C, –CN),
102.08 (1C, –C–(C=O)–N of quinoline), 40.56 (2C,
–N(CH3)2), 32.19 (1C, –N–CH3 of quinoline); Anal. Calcd.
For C22H19N7O2 C, 63.91; H, 4.63; N, 23.72% Found: C,
63.85; H, 4.55; N, 23.80%; ESI–MS (m/z): 414.40 429.39
(M?, 100%).
General procedure for the preparation of 4-(substituted
aliphaticamine)-6-(4-cyanophenylamino)-1,3,5,-
truiazine-2-yloxy)-1-methylquinolin-2(1H)-one (6a–o)
Mixture of compound 5 (1.01 g, 0.0025 mol), anhydrous
potassium carbonate (K2CO3) (0.35 g, 0.0025 mol), and
substituted aliphatic amine a–o (0.0025 mol) was stirred in
50 ml tetrahydrofuran. The reaction mixture was refluxed
for 5–24 h in water bath; progress of the reaction was
monitored by TLC using toluene/acetone (7:3, v/v) solvent
system as an eluent. After the completion of the reaction,
resultant mixture was poured on crushed ice. The solid
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4-(4-(Ethylamino)-6-(1-methyl-2-oxo-1,2-
dihydroquinolin-4-yloxy)-1,3,5-triazin-2-
ylamino)benzonitrile (6c)
4-(4-(Isopropylamino)-6-(1-methyl-2-oxo-1,2-
dihydroquinolin-4-yloxy)-1,3,5-triazin-2-
ylamino)benzonitrile (6e)
Yield: 55%; m.p. 118–122°C; (KBr cm-1): 3273 (N–H),
2960, 2892 (C–H in CH2 and CH3), 2228 (C:N), 1650
(C=O), 1326 (C–N in 2o aromatic amine), 1254 (C–O–C),
Yield: 81%; m.p. 116–118°C; IR (KBr cm-1): 3274 (N–H),
2968, 2888 (C–H in CH2 and CH3), 2222 (C:N), 1652
(C=O), 1320 (C–N in 2o aromatic amine), 1248 (C–O–C),
1
1
1128 (C–N in aliphatic amine), 835 (C3N3 s-triazine); H
1117 (C–N in aliphatic amine), 836 (C3N3 s-triazine); H
NMR (400 MHz, DMSO-d6): d 10.20 (s, 1H, –NH of
aminobenzonitrile linkage), 9.90 (s, 1H, –NH–CH2–CH3 of
ethy amine), 8.11–7.39 (m, 8H, Ar. –H), 6.50 (s, 1H, –CH–
(C=O)–N of quinoline), 3.63–3.52 (m, 5H, –NH–CH2–CH3
of ethyl amine and –N–CH3 quinoline); 1.24 (t,
J = 6.48 Hz, 3H, of –N–CH2–CH3 of ethyl amine); 13C
NMR (100 MHz, DMSO-d6): d 173.78 (1C, –C–NH–CH2–
CH3, of s-triazine to ethyl amine) 171.08 (1C, –C–O–C, s-
triazine to 4-HMQ linkage), 167.49 (1C, –C–NH of ami-
nobenzonitrile), 161.89 (1C, –C=O of quinoline), 155.01
(1C, –C–O–C, 4-HMQ linkage to s-triazine) 149.06–114.56
(12C, –Ar. C atoms), 103.90 (1C, –CN), 100.09 (1C, –C–
(C=O)–N of quinoline), 46.89 (1C, –CH2–CH3 of ethyl
amine), 31.09 (1C, –N–CH3 of quinoline), 15.12 (1C, –N–
CH2–CH3 of ethyl amine); Anal. Calcd. For C22H19N7O2:
C, 63.91; H, 4.63; N, 23.72% Found: C, 63.95; H, 4.68; N,
27.65%; ESI–MS (m/z): 414.38 (M?, 100%).
NMR (400 MHz, DMSO-d6): d 10.21 (s, 1H, –NH of
aminobenzonitrile linkage), 9.97 (s, 1H, –NH–CH(CH3)2
of isopropyl amine), 8.13–7.31 (m, 8H, Ar. –H), 6.39 (s,
1H, –CH–(C=O)–N of quinoline), 4.14 (m, J = 5.8 Hz,
1H, -CH), 3.59 (s, 3H, –N–CH3 of quinoline), 1.23 (dd,
J = 6.1, 1.7 Hz, 6H, 2CH3); 13C NMR (100 MHz, DMSO-
d6): d 172.01 (1C, –C–NH–CH(CH3)2 of s-triazine to iso-
propyl amine), 170.99 (1C, –C–O–C, s-triazine to 4-HMQ
linkage), 167.07 (1C, –C–NH of aminobenzonitrile),
161.01 (1C, –C=O of y quinoline), 153.39 (1C, –C–O–C,
4-HMQ linkage to s-triazine), 146.69–114.93 (12C, –Ar. C
atoms), 103.86 (1C, –CN), 100.98 (1C, –C–(C=O)–N of
quinoline), 42.45 (1C, –NH–CH(CH3)2 of s-triazine to
isopropyl amine), 32.87 (1C, –N–CH3 of quinoline), 20.99
(2C, –NH–CH(CH3)2 of s-triazine to isopropyl amine);
Anal. Calcd. For C23H21N7O2: C, 64.63; H, 4.95; N,
22.94% Found: C, 64.72; H, 4.91; N, 23.01%; ESI–MS
(m/z): 428.39 (M?, 100%).
4-(4-(Diethylamino)-6-(1-methyl-2-oxo-1,2-
dihydroquinolin-4-yloxy)-1,3,5-triazin-2-
ylamino)benzonitrile (6d)
4-(4-(Cyclopropylamino)-6-(1-methyl-2-oxo-1,2-
dihydroquinolin-4-yloxy)-1,3,5-triazin-2-
ylamino)benzonitrile (6f)
Yield: 73%; m.p. 84–87°C; IR (KBr cm-1): 3278 (N–H),
2955, 2880 (C–H in CH2 and CH3), 2221 (C:N), 1648
(C=O), 1315 (C–N in 2o aromatic amine), 1250 (C–O–C),
Yield: 46%; m.p. 234–236°C; IR (KBr cm-1): 3279 (N–H),
2953, 2880 (C–H in CH2), 2225 (C:N), 1650 (C=O),
1318 (C–N in 2o aromatic amine), 1246 (C–O–C), 1110
1
1120 (C–N in aliphatic amine), 830 (C3N3 s-triazine); H
1
NMR (400 MHz, DMSO-d6): d 10.19 (s, 1H, –NH of
aminobenzonitrile linkage), 8.16–7.29 (m, 8H, Ar. –H),
6.41 (s, 1H, –CH–(C=O)–N of quinoline), 3.63 (s, 3H, –N–
CH3 of quinoline); 3.22 (q, J = 6.40 Hz, 4H, –N–(CH2–
CH3)2 of dimethyl amine), 1.12 (t, J = 6.20 Hz, 6H, –N–
(CH2–CH3)2 of dimethyl amine); 13C NMR (100 MHz,
DMSO-d6): d 173.99 (1C, –C–O–C, s-triazine to 4-HMQ
linkage), 170.81 (1C, –C–NH of aminobenzonitrile),
169.88 (1C, –C–N(CH2–CH3)2, of s-triazine to diethyl
amine), 162.01 (1C, –C=O of quinoline), 154.19 (1C, –C–
O–C, 4-HMQ linkage to s-triazine) 149.69–115.03 (12C,
–Ar. C atoms), 105.65 (1C, –CN), 101.68 (1C, –C–(C=O)–
N of quinoline), 43.16 (2C, –N(CH2–CH3)2 of diethyl
amine), 34.29 (1C, –N–CH3 of quinoline), 13.94 (2C,
–N(CH2–CH3)2 of diethyl amine); Anal. Calcd. For
C24H23N7O2: C, 65.29; H, 5.25; N, 22.21% Found: C,
65.20; H, 5.15; N, 22.15%; ESI–MS (m/z): 442.52 (M?,
100%).
(C–N in aliphatic amine), 838 (C3N3 s-triazine); H NMR
(400 MHz, DMSO-d6): d 10.19 (s, 1H, –NH of amino-
benzonitrile linkage), 9.91 (s, 1H, –NH–CH(CH2)2 of
cyclopropyl amine), 8.11–7.36 (m, 8H, Ar. –H), 6.31 (s,
1H, –CH–(C=O)–N of quinoline), 3.51 (s, 3H, –N–CH3 of
quinoline), 3.08 (p, J = 9.8 Hz, 1H, –NH–CH(CH2)2
of cyclopropyl amine), 0.98–0.41 (m, 4H, –NH–CH(CH2)2
of cyclopropyl amine); 13C NMR (100 MHz, DMSO-d6): d
174.23 (1C, –C–O–C, s-triazine to 4-HMQ linkage),
170.81 (1C, –C–NH–CH(CH2)2 of s-triazine to cyclopropyl
amine), 166.88 (1C, –C–NH of aminobenzonitrile), 161.91
(1C, –C=O of quinoline), 151.26 (1C, –C–O–C, 4-HMQ
linkage to s-triazine), 145.29–113.01 (12C, –Ar. C atoms),
104.15 (1C, –CN), 101.56 (1C, –C–(C=O)–N of quinoline),
32.16 (1C, C-25, –N–CH3 of quinoline), 25.01 (1C, –NH–
CH(CH2)2 of s-triazine to cyclopropyl amine), 13.35 (2C,
–NH–CH(CH2)2 of s-triazine to cyclopropyl amine); Anal.
Calcd. For C23H19N7O2: C, 64.93; H, 4.50; N, 23.05%
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Found: C, 64.85; H, 4.53; N, 22.96%; ESI–MS (m/z):
426.43 (M?, 100%).
–CN), 101.16 (1C, –C–(C=O)–N of quinoline), 52.12 (1C,
–NH–CH(CH2)5 of cyclohexyl amine), 35.12–25.08 (6C,
–N–CH3 of quinoline and –NH–CH(CH2)5 of cyclohexyl
amine); Anal. Calcd. For C26H25N7O2: C, 66.79; H, 5.39;
N, 20.97% Found: C, 66.71; H, 5.30; N, 20.91%; ESI–MS
(m/z): 468.50 (M?, 100%).
4-(4-(Butylamino)-6-(1-methyl-2-oxo-1,2-
dihydroquinolin-4-yloxy)-1,3,5-triazin-2-
ylamino)benzonitrile (6g)
Yield: 51%; m.p. 156–158°C; IR (KBr cm-1): 3276 (N–H),
2932, 2892 (C–H in CH2 and CH3), 2221 (C:N), 1655
(C=O), 1322 (C–N in 2o aromatic amine), 1249 (C–O–C),
4-(4-(2-Chloroethylamino)-6-(1-methyl-2-oxo-1,2-
dihydroquinolin-4-yloxy)-1,3,5-triazin-2-
ylamino)benzonitrile (6i)
1
1121 (C–N in aliphatic amine), 839 (C3N3 s-triazine); H
NMR (400 MHz, DMSO-d6): d 10.21 (s, 1H, –NH of
aminobenzonitrile linkage), 9.95 (s, 1H, –NH–(CH2)3–CH3
of n-butyl amine), 8.15–7.31 (m, 8H, Ar. –H), 6.34 (s, 1H,
–CH–(C=O)–N of quinoline), 3.61 (s, 3H, –N–CH3 quin-
oline); 3.31 (m, 2H, –N–CH2–(CH2)2–CH3 of n-butyl
amine), 1.50–1.34 (m, 4H, –N–CH2–(CH2)2–CH3 of
n-butyl amine), 0.94 (t, J = 12.4 Hz, 3H, –N–(CH2)3–CH3
of n-butyl amine); 13C NMR (100 MHz, DMSO-d6): d
173.51 (1C, –C–NH–(CH2)3–CH3 of s-triazine to n-butyl
amine), 170.12 (1C, –C–O–C, s-triazine to 4-HMQ link-
age), 165.09 (1C, –C–NH of aminobenzonitrile), 162.16
(1C, –C=O of quinoline), 155.13 (1C, –C–O–C, 4-HMQ
linkage to s-triazine), 145.09–115.16 (12C, –Ar. C atoms),
105.18 (1C, –CN), 101.36 (1C, –C–(C=O)–N of quinoline),
43.17 (1C, –NH–CH2– (CH2)–CH3 of n-butyl amine),
32.87 (2C, –N–CH3 of quinoline and –NH–CH2–CH2–
CH2–CH3 of n-butyl amine), 21.87 (1C, –NH–(CH2)2–
CH2–CH3 of n-butyl amine), 13.12 (1C, –NH–(CH2)3–CH3
of n-butyl amine); Anal. Calcd. For C24H23N7O2: C, 65.29;
H, 5.25; N, 22.21% Found: C, 65.35; H, 5.33; N, 22.14%;
ESI–MS (m/z): 442.50 (M?, 100%).
Yield: 53%; m.p. 187°C; IR (KBr cm-1): 3271 (N–H),
2942, 2913 (C–H in CH2), 2221 (C:N), 1653 (C=O),
1317 (C–N in 2o aromatic amine), 1250 (C–O–C), 1110
1
(C–N in aliphatic amine), 842 (C3N3 s-triazine); H NMR
(400 MHz, DMSO-d6): d 10.28 (s, 1H, –NH of amino-
benzonitrile linkage), 9.92 (s, 1H,–NH–(CH2)2–Cl of
2-chloroethyl amine), 8.18–7.29 (m, 8H, Ar. –H), 6.20 (s,
1H, –CH–(C=O)–N of quinoline), 3.75 (t, J = 4.7 Hz, 2H,
–NH–CH2–CH2–Cl of 2-chloroethyl amine), 3.61(s, 3H,
–N–CH3 quinoline), 3.52 (t, J = 4.7 Hz, 2H, –NH–CH2–
CH2–Cl 2-chloroethyl amine); 13C NMR (100 MHz,
DMSO-d6): d 173.12 (1C, –C–NH–(CH2)2–Cl, of s-triazine
to 2-chloroethyl amine) 170.86 (1C, –C–O–C, s-triazine to
4-HMQ linkage), 165.88 (1C, –C–NH of aminobenzoni-
trile), 163.10 (1C, –C=O of quinoline), 155.12 (1C, –C–O–
C, 4-HMQ linkage to s-triazine) 149.25–114.45 (12C, –Ar.
C atoms), 104.16 (1C, –CN), 100.97 (1C, –C–(C=O)–N of
quinoline), 44.98 (2C, –NH–(CH2)2–Cl, of 2-chloroethyl
amine) 32.21 (1C, –N–CH3 of quinoline); Anal. Calcd. For
C22H18ClN7O2: C, 59.00; H, 4.05; N, 21.89% Found: C,
58.91; H, 4.13; N, 21.98%; ESI–MS (m/z): 448.85 (M?,
100%).
4-(4-(Cyclohexylamino)-6-(1-methyl-2-oxo-1,2-
dihydroquinolin-4-yloxy)-1,3,5-triazin-2-
ylamino)benzonitrile (6h)
4-(4-(2-Hydroxyethylamino)-6-(1-methyl-2-oxo-1,2-
dihydroquinolin-4-yloxy)-1,3,5-triazin-2-
ylamino)benzonitrile (6j)
Yield: 96%; m.p. 135–138°C; IR (KBr cm-1): 3279 (N–H),
2929, 2854 (C–H in CH2), 2224 (C:N), 1646 (C=O),
1319 (C–N in 2o aromatic amine), 1246 (C–O–C), 1116
Yield: 49%; m.p. 198–201°C; IR (KBr cm-1): 3460 (O–H
in primary alcohol), 3273 (N–H), 2946, 2911 (C–H in
CH2), 2226 (C:N), 1643 (C=O), 1346 (C–O–H in primary
alcohol), 1305 (C–N in 2o aromatic amine), 1261 (C–O–C),
1103 (C–N in aliphatic amine), 1031 (C–O in primary
alcohol), 839 (C3N3 s-triazine); 1H NMR (400 MHz,
DMSO-d6): d 10.19 (s, 1H, –NH of aminobenzonitrile
linkage), 9.93 (s, 1H, –NH–(CH2)2–OH of ethanol amine),
8.19–7.33 (m, 8H, Ar. –H), 6.31 (s, 1H, –CH–(C=O)–N of
quinoline), 4.68 (s, 1H, –NH–(CH2)2–OH of ethanol
amine), 3.72 (t, J = 4.4 Hz, 2H, –NH–CH2–CH2–OH of
ethanol amine), 3.63–3.48 (m, 5H, –N–CH3 of quinoline
and –NH–CH2–CH2–OH of ethanol amine); 13C NMR
(100 MHz, DMSO-d6): d 174.18 (1C, –C–NH–(CH2)2–
OH, of s-triazine to ethanol amine), 172.91 (1C, –C–O–C,
1
(C–N in aliphatic amine), 839 (C3N3 s-triazine); H NMR
(400 MHz, DMSO-d6): d 10.18 (s, 1H, –NH of amino-
benzonitrile linkage), 9.92 (s, 1H, –NH–CH(CH2)5 of
cyclohexyl amine), 8.18–7.31 (m, 8H, Ar. –H), 6.29 (s, 1H,
–CH–(C=O)–N of quinoline), 3.71 (s, 1H, –NH–CH(CH2)5
of cyclohexyl amine), 3.61 (s, 3H, –N–CH3 quinoline);
1.98–1.21 (m, 10H,–NH–CH(CH2)5 of cyclohexyl amine);
13C NMR (100 MHz, DMSO-d6): d 173.12 (1C, –C–O–C,
s-triazine to 4-HMQ linkage), 170.76 (1C, –C–NH–
CH(CH2)5 of s-triazine to cyclohexyl amine), 165.09 (1C,
–C–NH of aminobenzonitrile), 162.11 (1C, –C=O of
quinoline), 150.07 (1C, –C–O–C, 4-HMQ linkage to s-tri-
azine), 148.89–115.17 (12C, –Ar. C atoms), 105.10 (1C,
123

Med Chem Res (2012) 21:3182–3194
3187
s-triazine to 4-HMQ linkage), 168.09 (1C, –C–NH of
aminobenzonitrile), 162.89 (1C, –C=O of quinoline),
154.21 (1C, –C–O–C, 4-HMQ linkage to s-triazine)
145.85–115.01 (12C, –Ar. C atoms), 103.78 (1C, –CN),
102.19 (1C, –C–(C=O)–N of quinoline), 65.65 (1C, –NH–
CH2–CH2–OH of ethanol amine), 45.89 (1C, –NH–CH2–
CH2–OH of ethanol amine) 31.68 (1C, –N–CH3 of quin-
oline); Anal. Calcd. For C22H19N7O3: C, 61.53; H, 4.46; N,
22.83% Found: C, 61.60; H, 4.40; N, 22.74%; ESI–MS (m/
z): 430.43 (M?, 100%).
aminobenzonitrile), 163.11 (1C, –C=O of quinoline), 152.76
(1C, –C–O–C, 4-HMQ linkage to s-triazine), 147.89–114.75
(16C, –Ar. C atoms), 104.68 (1C, –CN), 102.89 (1C, –C–
(C=O)–N of quinoline), 41.24 (1C, –NH–CH2–CH2–C4H3S
of thiophen-2-ethyl amine), 32.66 (2C, –N–CH3 of quinoline
and –NH–CH2–CH2–C4H3S of thiophen-2-ethyl amine);
Anal. Calcd. For C26H21N7O2S: C, 63.02; H, 4.27; N,
19.79% Found: C, 63.11; H, 4.32; N, 19.72%; ESI–MS (m/z):
496.59 (M?, 100%).
4-(4-(2-(5-Methoxy-1H-indol-3-yl)ethylamino)-6-(1-
methyl-2-oxo-1,2-dihydroquinolin-4-yloxy)-1,3,5-
triazin-2-ylamino)benzonitrile (6m)
4-(4-(Benzylamino)-6-(1-methyl-2-oxo-1,2-
dihydroquinolin-4-yloxy)-1,3,5-triazin-2-
ylamino)benzonitrile (6k)
Yield: 60%; m.p. 139–142°C; IR (KBr cm-1): 3271 (N–H),
2945, 2909 (C–H in CH2), 2821 (C–H in O–CH3), 2225
(C:N), 1648 (C=O), 1316 (C–N in 2o aromatic amine),
1250 (C–O–C), 1120 (C–N in aliphatic amine), 838 (C3N3
Yield: 96%; m.p. 154–155°C; IR (KBr cm-1): 3278 (N–H),
2938, 2909 (C–H in CH2), 2224 (C:N), 1649 (C=O),
1321 (C–N in 2o aromatic amine), 1248 (C–O–C), 1112
1
1
(C–N in aliphatic amine), 838 (C3N3 s-triazine); H NMR
s-triazine); H NMR (400 MHz, DMSO-d6): d 11.01 (s,
(400 MHz, DMSO-d6): d 10.22 (s, 1H, –NH of amino-
benzonitrile linkage), 9.97 (s, 1H, –NH–CH2–C6H5 of
benzyl amine), 8.20–7.25 (m, 13H, Ar. –H), 6.15 (s, 1H,
–CH–(C=O)–N of quinoline), 4.85 (s, 2H, –NH–CH2–C6H5
of benzyl amine), 3.61(s, 3H, –N–CH3 quinoline); 13C
NMR (100 MHz, DMSO-d6): d 175.12 (1C, –C–O–C,
s-triazine to 4-HMQ linkage), 171.87 (1C, –C–NH–CH2–
C6H5 of s-triazine to cyclohexyl amine), 165.09 (1C, –C–
NH of aminobenzonitrile), 163.19 (1C, –C=O of quino-
line), 151.01 (1C, –C–O–C, 4-HMQ linkage to s-triazine),
147.81–114.69 (18C, –Ar. C atoms), 104.47 (1C, –CN),
103.14 (1C, –C–(C=O)–N of quinoline), 44.43 (1C, –NH–
CH2–C6H5 of cyclohexyl amine), 33.12 (1C, –N–CH3 of
quinoline); Anal. Calcd. For C27H21N7O2: C, 68.20; H,
4.45; N, 20.62% Found: C, 68.09; H, 4.51; N, 20.56%;
ESI–MS (m/z): 476.47 (M?, 100%).
1H, –NH of 5-methoxy-1H-indole), 10.12 (1H, s, –NH of
aminobenzonitrile linkage), 9.88 (s, 1H of –NH of 2-(5-
methoxy-1H-indol-3-yl)ethylamino), 8.15–6.95 (m, 12H of
Ar. –H), 6.33 (s, 1H, –CH–(C=O)–N of quinoline), 3.89 (s,
3H, –O–CH3 of 2-(5-methoxy-1H-indol-3-yl)ethylamino),
3.60 (s, 3H, –N–CH3 quinoline), 3.45 (t, J = 7.8 Hz, 2H,
–NH–CH2–CH2– of 2-(5-methoxy-1H-indol-3-yl)ethyl-
amino), 2.43 (t, J = 7.8 Hz, 2H, –NH–CH2–CH2– of 2-(5-
methoxy-1H-indol-3-yl)ethylamino); 13C NMR (100 MHz,
DMSO-d6): d 174.02 (1C, –C–NH–CH2–CH2– of s-triazine
to 2-(5-methoxy-1H-indol-3-yl)ethylamino), 172.43 (1C,
–C–O–C, s-triazine to 4-HMQ linkage), 166.88 (1C, –C–
NH of aminobenzonitrile), 162.56 (1C, –C=O of quino-
line), 153.61 (1C, –C–O–C, 4-HMQ linkage to s-triazine),
146.12–107.83 (20C, –Ar. C atoms), 104.55 (1C, –CN),
101.26 (1C, –C–(C=O)–N of quinoline), 59.21 (1C, –O–
CH3 of 2-(5-methoxy-1H-indol-3-yl)ethylamino), 40.31
(1C, –NH–CH2–CH2– of 2-(5-methoxy-1H-indol-3-yl)eth-
ylamino), 31.81 (1C, –N–CH3 of quinoline), 23.44 (1C,
–NH–CH2–CH2– of 2-(5-methoxy-1H-indol-3-yl)ethyl-
amino); Anal. Calcd. For C31H26N8O3: C, 66.66; H, 4.69;
N, 20.06% Found: C, 66.58; H, 4.64; N, 20.13%; ESI–MS
(m/z): 559.60 (M?, 100%).
4-(4-(1-Methyl-2-oxo-1,2-dihydroquinolin-4-yloxy)-6-
(2-(thiophen-2-yl)ethylamino)-1,3,5-triazin-2-
ylamino)benzonitrile (6l)
Yield: 95%; m.p. 138–141°C; IR (KBr cm-1): 3274 (N–H),
2941, 2913 (C–H in CH2), 2222 (C:N), 1652 (C=O), 1319
(C–N in 2o aromatic amine), 1270 (C–S in thiophine)1244
(C–O–C), 1119 (C–N in aliphatic amine), 833 (C3N3 s-tri-
2-(4-(4-Cyanophenylamino)-6-(1-methyl-2-oxo-1,2-
dihydroquinolin-4-yloxy)-1,3,5-triazin-2-
ylamino)acetic acid (6n)
1
azine); H NMR (400 MHz, DMSO-d6): d 10.19 (s, 1H,
–NH of aminobenzonitrile linkage), 9.92 (s, 1H, –NH–CH2–
CH2–C4H3S of thiophen-2-ethyl amine), 8.18–6.98 (m,
11H, Ar. –H), 6.29 (s, 1H, –CH–(C=O)–N of quinoline),
3.63 (s, 3H, –N–CH3 quinoline), 3.21 (d, J = 18.8 Hz,
4H, –NH–CH2–CH2–C4H3S); 13C NMR (100 MHz, DMSO-
d6): d 171.98 (1C, –C–NH–(CH2)2–C4H3S of s-triazine
to thiophen-2-ethyl amine), 173.11 (1C, –C–O–C, s-tri-
azine to 4-HMQ linkage), 167.56 (1C, –C–NH of
Yield: 70%; m.p. 204–206°C; IR (KBr cm-1): 3275 (N–H),
2880 (O–H in glycine), 2223 (C:N), 1714 (C=O in gly-
cine), 1648 (C=O), 1311 (C–N in 2o aromatic amine), 1276
(C–O in glycine), 1248 (C–O–C), 1113 (C–N in aliphatic
amine), 839 (C3N3 s-triazine); 1H NMR (400 MHz,
DMSO-d6): d 13.52 (s, 1H, –NH–CH2–(C=O)–OH of
123

3188
Med Chem Res (2012) 21:3182–3194
glycine), 10.24 (s, 1H, –NH of aminobenzonitrile linkage),
9.92 (s, 1H, –NH–CH2–(C=O)–OH of glycine), 8.28–7.15
(m, 8H, Ar. –H), 6.13 (s, 1H, –CH–(C=O)–N of quinoline),
3.87 (s, 2H, –NH–CH2–(C=O)–OH of glycine), 3.60 (s,
3H, –N–CH3 quinoline); 13C NMR (100 MHz, DMSO-d6):
d 175.43 (2C, –C–O–C, s-triazine to 4-HMQ linkage and
–NH–CH2–(C=O)–OH of glycine), 171.89 (1C, –C–NH–
CH2–(C=O)–OH of s-triazine to glycine), 167.26 (1C, –C–
NH of aminobenzonitrile), 162.56 (1C, –C=O of quino-
line), 151.69 (1C, –C–O–C, 4-HMQ linkage to s-triazine),
148.12–114.83 (12C, –Ar. C atoms), 105.26 (1C, –CN),
100.98 (1C, –C–(C=O)–N of quinoline), 48.39 (1C, –NH–
CH2–(C=O)–OH of glycine), 33.12 (1C, –N–CH3 of
quinoline); Anal. Calcd. For C22H17N7O4: C, 59.59; H,
3.86; N, 22.11% Found: C, 59.52; H, 3.91; N, 22.04%;
ESI–MS (m/z): 444.38 (M?, 100%).
(Staphylococcus aureus MTCC 96, Bacillus cereus MTCC
619, Escherichia coli MTCC 739, Pseudomonas aeruginosa
MTCC 741, Klebsiella pneumoniae MTCC 109, Salmonella
typhi MTCC 733, Proteus vulgaris MTCC 1771, and
Shigella Flexneria MTCC 1457) and fungi (Aspergillus
niger MTCC 282, and Candida albicans MTCC 183) species
using paper disc diffusion technique (Gillespie, 1994). The
Mueller–Hinton agar media were sterilized (autoclaved at
120°C for 30 min), poured at uniform depth of 5 mm, and
allowed to solidify. The microbial suspension (105 CFU/mL)
(0.5 McFarland Nephelometery Standards) was streaked
over the surface of media using a sterile cotton swab to
ensure even growth of the organisms. The tested compounds
were dissolved in dimethylsulfoxide to give solutions of
3.12–50 lg/ml. Sterile filter paper discs measuring 6.25 mm
in diameter (Whatman no. 1 filter paper), previously soaked
in a known concentration of the respective test compound in
dimethylsulfoxide were placed on the solidified nutrient agar
medium that had been inoculated with the respective
microorganism, and the plates were incubated for 24 h at
(37 1) °C. A control disc impregnated with an equivalent
amount of dimethylsulfoxide without any sample was also
used, and it did not produce any inhibition. Ciprofloxacin and
ketoconazole (50 lg/disc) were used as control drugs for
antibacterial and antifungal activities, respectively.
Ethyl-2-(4-(4-cyanophenylamino)-6-(1-methyl-2-oxo-
1,2-dihydroquinolin-4-yloxy)-1,3,5-triazin-2-
ylamino)acetate (6o)
Yield: 78%; m.p. 240°C; IR (KBr cm-1): 3278 (N–H), 2939,
2909 (C–H in CH2 and CH3), 2221 (C:N), 1739 (C=O in
glycineethyl ester), 1642 (C=O), 1309 (C–N in 2o aromatic
amine), 1243 (C–O–C), 1218 (C–O in glycineethyl ester),
1
1120 (C–N in aliphatic amine), 833 (C3N3 s-triazine); H
MIC of the compound was determined by agar streak
dilution method (Hawkey and Lewis, 1994). A stock solution
of the synthesized compound (50 lg/ml) in dimethylsulf-
oxide was prepared, and graded quantities of the test com-
pounds were incorporated in a specified quantity of molten
sterile agar, i.e., nutrient agar for evaluation of antibacterial
activity, and sabouraud dextrose agar for antifungal activity,
respectively. The medium containing the test compound was
poured into a Petri dish at a depth of 4–5 mm and allowed to
solidify under aseptic conditions. A suspension of the
respectivemicroorganism ofapproximately 105 CFU/mLwas
prepared and applied to plates with serially diluted com-
pounds with concentrations in the range of 3.12–50 lg/ml in
dimethylsulfoxide and incubated at (37 1) °C for 24 h
(bacteria) or 48 h (fungi). The lowest concentration of the
substance that prevents the development of visible growth is
considered to be the MIC value.
NMR (400 MHz, DMSO-d6): d 10.14 (s, 1H, –NH of ami-
nobenzonitrile linkage), 9.89 (s, 1H, –NH–CH2–(C=O)–O–
CH2–CH3 of glycine ethylester), 8.21–7.11 (m, 8H, Ar. –H),
6.09 (s, 1H, –CH–(C=O)–N of quinoline), 3.62 (s, 3H, –N–
CH3 quinoline), 3.31 (s, 2H, –NH–CH2–(C=O)–O–CH2–
CH3 of glycine ethylester), 2.23 (t, J = 8.3 Hz, 3H, –NH–
CH2–(C=O)–O–CH2–CH3 of glycine ethylester), 1.89 (q,
J = 11.7 Hz, 2H, –NH–CH2–(C=O)–O–CH2–CH3 of gly-
cine ethylester); 13C NMR (100 MHz, DMSO-d6): d 174.68
(1C, –C–O–C, s-triazine to 4-HMQ linkage and –NH–CH2–
(C=O)–OH of glycine), 170.99 (2C, –C–NH–CH2–(C=O)–
O–CH2–CH3 of s-triazine to glycine ethylester), 166.69 (1C,
–C–NH of aminobenzonitrile), 161.10 (1C, –C=O of quin-
oline), 153.96 (1C, –C–O–C, 4-HMQ linkage to s-triazine),
146.86–115.03 (12C, –Ar. C atoms), 105.47 (1C, –CN),
101.56 (1C, –C–(C=O)–N of quinoline), 63.55 (1C, –NH–
CH2–(C=O)–O–CH2–CH3 of glycine ethylester), 46.96 (1C,
–NH–CH2–(C=O)–O–CH2–CH3 of glycine ethylester),
31.23 (1C, –N–CH3 of quinoline), 12.76 (1C, –NH–CH2–
(C=O)–O–CH2–CH3 of glycine ethylester); Anal. Calcd. For
C24H21N7O4: C, 61.14; H, 4.49; N, 20.80% Found: C, 61.22;
H, 4.43; N, 20.93%; ESI–MS (m/z): 472.50 (M?, 100%).
Results and discussion
Chemistry
The designed target compounds were obtained as outlined in
Scheme 1. The first step comprises formation of intermedi-
ate 3 in very good Yield: 90% by the nucleophilic dis-
placement of one chlorine atom of s-triazine ring by
4-amino-benzonitrile. In FT-IR analysis, a C3N3 stretching
In vitro evaluation of antimicrobial activity
The synthesized s-triazinyl derivatives 6a–o were examined
for their antimicrobial activity against several bacteria
123

Med Chem Res (2012) 21:3182–3194
3189
Scheme 1 Schematic diagram
for the synthesis of final
s-triazine derivatives
Cl
N
NH2
Cl
N
Cl
NC
Acetone, 0 - 5 °C, K2CO3
N
N
+
N
N
N
Cl
H
Cl
CN
1
3
2
H
N
N
O
OH
Acetone, 40 - 45°C, K2CO3
N
N
N
3
+
NC
CH3
Cl
O
N
O
CH3
5
4
H
N
N
O
THF, Reflux, K2CO3
NH2 — R
5
+
N
N
N
NC
CH3
R
O
6a-o
Where: –R =
H3C
H2
C
CH3
N
CH2
CH3
HN CH
CH3
CH3
HN
H
CH2
CH2
HN
CH3
N
HN
C
CH3
CH2
H3C
a
b
c
d
e
f
H2
C
H2
C
H2
C
H2
C
OH
HN
HN
HN
C
HN
HN
C
CH3
H2
H2
C
C
Cl
H2
H2
g
h
i
j
k
H
N
S
H2
C
CH3
O
C
O
H2C
HN
CH2
O
H2
C
HN
C
HN
HN
H2
C
OH
C
O
CH3
H2
H2
l
m
n
o
in the s-triazine ring was observed at 833 cm-1. In the IR
spectrum of compound 1, absorption band seen at
2228 cm-1 was assigned to C:N group, and a strong band
near 3277 cm-1 further confirmed the presence of a –NH
group. The synthesis of disubstituted s-triazine intermedi-
ate 5 was achieved at Yield: 88% by the reaction
between 4-(4,6-dichloro-1,3,5-triazin-2-ylammino)benzo-
nitrile 3 and 4-hydroxy-N-methylquinolin-2(1H)-one 4 in
the presence of potassium carbonate at 40–45°C, and the
presence of C–O–C linkage in the proposed structures of
compound 5 was indicated by the appearance of stretching
bands at 1256 cm-1 in its IR spectra, while disappearance of
the –OH peak at 3640 cm-1, corresponding to the
4-hydroxy-N-methylquinolin-2(1H)-one, gave correction to
the formation of the said intermediate. Subsequent coupling
of the so-formed intermediate with the preferred substituted
123

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Med Chem Res (2012) 21:3182–3194
Table 1 In-vitro antimicrobial activity
H
N
R
O
N
N
N
N
NC
CH3
O
Entry
R
log p
Zone of inhibition [mm (MIC in lg/mL)]
S.a
B.c
E.c
P.a
K.p
(50)
S.t
P.v
S.f
6a
3.64
11 (50)
07 (50)
\5 (50)
14 (6.25)
\5 (50)
08 (50)
08 (50)
CH3
HN
CH3
6b
6c
6d
4.43
3.98
5.10
12 (50)
10 (50)
13 (25)
14 (12.5)
\5 (50)
10 (50)
08 (50)
11 (50)
08 (50)
(50)
(50)
(50)
07 (50)
09 (50)
10 (50)
09 (50)
\5 (50)
\5 (50)
\5 (50)
07 (50)
10 (50)
N
CH3
H2
C
12 (12.5)
10 (50)
HN
CH3
H3C
CH2
N
16 (12.5)
CH2
CH3
CH3
HN CH
CH3
6e
6f
4.29
3.93
4.88
5.19
4.35
3.12
5.37
5.46
5.06
08 (50)
\5 (50)
12 (50)
13 (25)
11 (25)
08 (50)
10 (50)
11 (50)
\5 (50)
10 (50)
13 (25)
13 (25)
09 (50)
07 (50)
\5 (50)
08 (50)
15 (25)
\5 (50)
09 (50)
10 (50)
09 (50)
\5 (50)
06 (50)
11 (25)
\5 (50)
07 (50)
09 (50)
07 (50)
10 (50)
09 (50)
(50)
11 (25)
(50)
06 (50)
\5 (50)
06 (50)
\5 (50)
13 (25)
09 (50)
\5 (50)
12 (50)
\5 (50)
08 (50)
08 (50)
\5 (50)
07 (50)
08 (50)
07 (50)
\5 (50)
07 (50)
06 (50)
08 (50)
\5 (50)
07 (50)
09 (50)
\5 (50)
07 (50)
06 (50)
14 (25)
12 (50)
HN
H2 H2
C
C
6g
6h
6i
HN
C
CH3
H2
14 (6.25)
12 (25)
13 (12.5)
(50)
HN
H2
C
HN
C
Cl
H2
H2
C
OH
6j
\5 (50)
13 (12.5)
15 (6.25)
15 (6.25)
(50)
HN
HN
C
H2
6k
6l
15 (12.5)
10 (50)
10 (50)
C
H2
S
H2
C
HN
HN
C
H2
O
CH2
H2C
CH3
6m
N
H
123

Med Chem Res (2012) 21:3182–3194
3191
Table 1 continued
Entry
R
log p
Zone of inhibition [mm (MIC in lg/mL)]
S.a
B.c
E.c
P.a
K.p
(50)
S.t
P.v
S.f
O
C
6n
2.90
\5 (50)
07 (50)
\5 (50)
08 (50)
08 (50)
13 (25)
09 (50)
HN
C
OH
H2
O
H2
C
HN
6o
3.51
06 (50)
09 (50)
07 (50)
\5 (50)
(50)
08 (50)
15 (12.5)
11 (50)
C
O
CH3
H2
Cip.
17 (1.0)
–
16 (1.0)
–
18 (1.0)
–
15 (1.0)
–
16 (1.0)
–
16 (1.0)
–
17 (1.0)
–
17 (B3)
DMSO
–
Cip. Ciprofloxacin, S.a Staphylococcus aureus, B.c Bacillus cereus, E.c Escherichia coli, P.a Pseudomonas aeruginosa, K.p Klebsiella pneumoniae, S.t Salmonella
typhi, P.v Proteus vulgaris, S.f Shigella flexneria
Table 2 In-vitro antifungal activity
H
N
R
O
N
N
N
N
NC
CH3
O
Entry
R
log p
Zone of inhibition [mm (MIC in lg/ml)]
A.n
C.a
6a
3.64
\5 ([50)
\5 ([50)
CH3
HN
CH3
6b
6c
6d
6e
6f
4.43
3.98
5.10
4.29
3.93
4.88
5.19
\5 ([50)
\5 ([50)
09 (50)
\5 ([50)
\5 ([50)
09 (50)
07 (50)
08 (50)
06 (50)
10 (50)
N
CH3
H2
C
HN
CH3
H3C
CH2
N
CH2
CH3
CH3
HN CH
CH3
08 (50)
10 (50)
HN
H2 H2
C
C
6g
6h
\5 ([50)
09 (50)
HN
C
CH3
H2
HN
123

3192
Med Chem Res (2012) 21:3182–3194
Table 2 continued
Entry
R
log p
Zone of inhibition [mm (MIC in lg/ml)]
A.n
C.a
H2
C
6i
4.35
08 (50)
09 (50)
HN
C
Cl
H2
H2
C
OH
6j
3.12
5.37
5.46
5.06
\5 ([50)
\5 ([50)
13 (25)
\5 ([50)
\5 ([50)
15 (25)
HN
HN
C
H2
6k
6l
C
H2
S
H2
C
HN
HN
C
H2
O
CH2
H2C
CH3
6m
12 (25)
15 (25)
N
H
O
C
HN
6n
2.90
3.51
07 (50)
\5 ([50)
C
OH
O
H2
H2
C
6o
09 (50)
\5 ([50)
HN
C
O
CH3
Kit.
H2
16 (B3)
17 (1.0)
DMSO
–
–
Kit Ketoconazole, A.n Aspergillus niger, C.a Candida albicans
aliphatic amines under basic conditions in tetrahydrofuran
solvent at 70–80°C formed the corresponding 1,3,5-triazines
(6a–o). This reaction proceeded in good Yield: 46–96% and
is general for different substituted aliphatic amines. The
correctness of the synthesis of 6a–o was confirmed on the
(14 mm), while compound 6k involving phenyl ring
appeared with half-fold MIC value (12.5 lg/mL) when
compared to 6l and 6m. It is worthy to note that the said
compound 6 l displayed potent inhibitory action against
Gram-negative S. flexneria at 25 lg/mL of MIC and
15 mm of inhibitory zone. Furthermore, compounds 6d and
6b with the substitution of alkyl chain to the nitrogen atom
of the coupling agent displayed significant growth inhibi-
tion of Gram-positive B. cereus at 12.5 lg/mL of MIC, 16
and 14 mm of growth inhibitory diameter’s, respectively.
Final analogue with halogen-substituted coupling amine
(6i) displayed good activity against Gram-negative E. coli
and S. typhi at 25 lg/mL of MIC, 15 and 13 mm of inhi-
bition zones, respectively; however, all the remaining
scaffolds displayed higher MICs against both the bacteria.
Final scaffolds (6a, 6c, and 6g) with the alkyl amine chain
as a coupling agent displayed activity in the decreasing
order of the chain length in terms of MIC as 6.25 lg/mL,
12.5 lg/mL, and 25 lg/mL and inhibition zones of 14, 12,
and 11 mm, respectively, against P. aeruginosa. Inhibition
of Gram-negative bacteria K. pneumoniae was promisingly
1
basis of H NMR, 13C NMR, and Mass spectra of the syn-
thesized compounds and the purity was ascertained by ele-
mental analysis.
Biological activities
Biological assay summarized in Tables 1 and 2 revealed
that all the newly synthesized compounds indicated good-
to-excellent bioactivities against the different microorgan-
isms studied. Final s-triazine analogues 6l and 6m bearing
heterocyclic functionality to the coupling agent exhibited
excellent activity against Gram-pistive S. aureus at
6.25 lg/mL of MIC and 15 mm of inhibition zone. In
addition, compound 6h with the substitution of cyclohexyl
amine as coupling agent indicated similar MIC value as 6l
and 6m by deviating slightly in the inhibition zone
123

Med Chem Res (2012) 21:3182–3194
3193
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123