Synthesis of novel triazol compounds containing isatin as potential antibacterial and antifungal agents by microwave and conventional methods

Article abstract of DOI:10.3184/174751911X13043524455143

Microwave irradiation has been used to accelerate the conversion of isatin (1a) and 5-nitroisatin (1b) into their Schiff bases 3-[5′-aryl(alkyl)- 2′,4′-dihydro-1′,2′,4′-triazol-3′-on- 4′-yl]iminoisatin (3a-g) and 3-[5′-aryl(alkyl)-2′,4′- dihydro-1′,2′,4′-triazol-3′-on-4′-yl] imino-5-nitroisatin (4a-g), respectively. Reaction was achieved by microwave-induced technique, which reduced the reaction time drastically and improved the yield when compared to conventional heating. The newly synthesised bases showed moderate antimicrobial activity against the standard bacterial and fungal organisms tested.

Full text of DOI:10.3184/174751911X13043524455143

268 RESEARCH PAPER
MAY, 268–271
JOURNAL OF CHEMICAL RESEARCH 2011
Synthesis of novel triazol compounds containing isatin as potential
antibacterial and antifungal agents by microwave and conventional
methods
˙
Musa Özil,* Emre Mentes˛e, Fatih Yılmaz, Fatih Islamog˘lu and Bahittin Kahveci
Department of Chemistry, Art and Science Faculty, Rize University, 53100 Rize-Turkey
Microwave irradiation has been used to accelerate the conversion of isatin (1a) and 5-nitroisatin (1b) into their Schiff
bases 3-[5′-aryl(alkyl)-2′,4′-dihydro-1′,2′,4′-triazol-3′-on-4′-yl]iminoisatin (3a–g) and 3-[5′-aryl(alkyl)-2′,4′-dihydro-
1′,2′,4′-triazol-3′-on-4′-yl]imino-5-nitroisatin (4a–g), respectively. Reaction was achieved by microwave-induced tech-
nique, which reduced the reaction time drastically and improved the yield when compared to conventional heating.
The newly synthesised bases showed moderate antimicrobial activity against the standard bacterial and fungal
organisms tested
Keywords: isatin, 5-nitroisatin, Schiff bases, microwave irradiation, triazoles, antibacterial, antifugal
In recent years, microwave-assisted reactions have attracted
much research interest because of the simplicity of operation,
enhanced reaction rates and high selectivity. Thus, microwave
irradiation, which has become a powerful synthetic tool for the
rapid synthesis of biologically active compounds, is used to
enhance the rates of classical organic reactions.1–4
Isatin and its derivatives have attracted the attention of
chemists mainly because of the broad spectrum biological
properties exhibited by this class of compounds.5–11 Triazol
compounds have also been found to be associated with diverse
pharmacological activities such as having antibacterial, anti-
fungal, anticancer and anticonvulsant properties.12–15 In the
present study, these two types of compound were incorporated
into a single structure using Schiff’s reactions. This report
deals with the synthesis of Schiff’s bases by reacting isatin and
5-nitroisatin with triazol and its derivatives by using micro-
wave irradiation and conventional heating. We have aimed to
achieve a better antimicrobial profile at lower concentrations
with these compounds.
In previous work from our laboratory, we reported the syn-
thesis of a number of triazoles by conventional methods.16
Recently, we became interested in the use of microwave irra-
diation (MW) in organic synthesis17,18 since its use can provide
improvements in environmental and economical aspects.19–21
Here, microwave irradiation has been used for the practical
conversion of biological available isatin and 5-nitroisatin into
Schiff bases with triazol and its derivatives. Also we compared
conventional heating with microwave irradiation with respect
to for yields and reaction times. The compounds were charac-
terised by 1H NMR, 13C NMR, IR and elemental analysis.
Treatment of isatin (1a) or 5-nitroisatin (1b) with com-
pounds 2a–g resulted in formation of 3a–g and 4a–g respec-
tively (Scheme 1). These reactions were carried out in an oil
bath and yields were moderate. They were also carried out
under microwave irradiation in ethanol in closed vessels with
pressure control at 110 °C for 3–5 min (hold time) at 300 W
maximum power. Using this method the yields were greater
than from conventional heating and also reaction time are
reduced from 4–5 h to 3–5 min (Table 1).
Spectroscopic investigations of the newly synthesised
compounds are in accordance with the proposed structures.
Comparison of the IR spectra of each step gave some informa-
tion as to nature of the products. In this context, comparison of
the IR spectroscopic data clearly indicated the formation of
compounds 3a–g and 4a–g by the disappearance of the NH2
band in compounds 2a–g at about 3400 cm−1 and the appear-
ance of a new C=N band at about 1610 cm−1, a new C=O band
at about 1730 cm−1 and a new NH band at about 3230 cm−1 in
compounds 3a–g and 4a–g.
1H NMR spectra are also consistent with the proposed struc-
1
tures. Comparison of the H NMR spectroscopic data clearly
indicated the formation of compounds 3a–g and 4a–g by the
appearance of signals corresponding to two different NH
protons at about 11.00–12.20 ppm and the disappearance
of the NH2 protons in compounds 2a–g at about 5.10 ppm.
The 13C NMR spectra of 3a–g and 4a–g show two signals
indicating the appearance of C=O groups at about 163 ppm
and 153 ppm. In addition, the elemental analytical results of
the compounds 3a–g and 4a–g show good agreement with the
calculated values.
Antibacterial and antifungal activity: Compounds 4a, 4b
and 3b showed just a moderate antifungal activity with slight
differences. Compound 3g exhibited a noteworthy antibacte-
rial effect with the MIC of 8 and 16 µg mL−1 to Staphylococcus
aureus and Bacillus subtilis, respectively. Although it is known
that the triazole derivatives have antifungal activity, and one
group of the antifungal agents in clinical use,23 compound 3g
showed antibacterial activity, especially to the Gram positive
organisms.
Results and discussion
Chemistry: We prepared isatin (1a) and 5-nitroisatin (1b) and
converted them into their Schiff bases 3-[5′-aryl(alkyl)-2′,
4′-dihydro-1′,2′,4′-triazol-3′-on-4′-yl]iminoisatin (3a–g) and
3-[5′-aryl(alkyl)-2′,4′-dihydro-1′,2′,4′-triazol-3′-on-4′-yl]imino-
5-nitroisatin (4a–g). Compound 1a–b were obtained by the
reaction of aniline and 4-nitroaniline respectively with
aqueous trichloroacetaldehyde and hydroxylamine using the
published methods (Scheme 1).22
Ethoxycarbonylhydrazones can be considered as useful
intermediates leading to the formation of some heterocycles
such as 1,2,4-triazole-3-ones. Therefore, compounds 2a–g
were obtained by the reaction of ethoxycarbonylhydrazones
with hydrazine hydrate under microwave irradiation in water
using closed vessels with pressure control at 90 °C for 3 min
(hold time) at 300 W maximum power (Scheme 1).
The remaining compounds had moderate antimicrobial
activity against the standard microorganisms tested with the
MIC of 62 to 500 µg mL−1, as seen in Table 2.
Experimental
Chemistry
Melting points were taken on capillary tubes in a Büchi oil heated
melting point apparatus and are uncorrected. 1H NMR and 13C NMR
spectra were recorded on a Varian-Mercury 200 MHz spectrophotom-
eter (solvent DMSO-d6, TMS as internal standard). The IR spectra
* Correspondent. E-mail: musa.ozil@rize.edu.tr

JOURNAL OF CHEMICAL RESEARCH 2011 269
Scheme 1 Synthetic pathway for the preparation of compounds.
were recorded for KBr pellets on an Perkin-Elmer 100 FTIR spectro-
photometer. Elemental analyses were performed on a Carlo Erba 1106
CHN analyser. Starting materials were obtained from Fluka orAldrich.
A monomode CEM-Discover Microwave was used in the standard
configuration as delivered, including proprietary software. All experi-
ments were carried out in microwave process vials (30 mL) with con-
trol of the temperature by IR detection temperature sensor. For safety
reasons, the maximum temperature allowed was set to 200 °C and
the maximum pressure was 12 bars. Pressure and temperature
were monitored during the whole reaction by a pressure sensor and
infrared detection temperature sensor. The microwave instrument was
monitored by a computer and conditions maintained constant by a
discrete modulation of delivered microwave power. After completion
of the reaction, the vial was cooled to 60 °C by air jet cooling. Com-
pounds 1a–b were synthesised according to the published methods.22
Compounds 2a–g were synthesised by a new technique; however,
these compounds are recorded in the literature.24–26
of the reaction, (monitored by TLC, ethyl acetate:hexane, 3:1) the
mixture was cooled to room temperature. The resulting solid was
recrystallised from ethanol–water to afford compounds 2a–g.
General method for the synthesis of 3a–g and 4a–g
Conventional method. Equimolar quantities (0.01 mol) of isatin
(5-nitroisatin) and the corresponding amino compound (2a–g) were
dissolved in warm ethanol (40 mL) containing glacial acetic acid
(0.5 mL). The reaction mixture was refluxed for 5 h (4h for 4a–g)
(monitored by TLC, ethylacetate:Hexane, 3:1) and then kept at
room temperature overnight. The resulting solid was washed with
ethanol, dried and recrystallised from ethanol–chloroform to afford
compounds 3a–g and 4a–g.
Microwave method: A mixture of 2a–g (0.01 mol) and isatin
(5-nitroisatin) (0.01 mol) in ethanol (15 mL) (containing 0.5 mL
glacial acetic acid) was irradiated in the closed vessels with pressure
control at 110 °C for 5 min (3 min for 4a–g) (hold time) at 300 W
maximum power. After the completion of the reaction, (monitored by
TLC, ethyl acetate:hexane, 3:1) the above purification methods were
also applied to this material.
General method for the synthesis of 2a–g
Microwave method:
A mixture of ethoxycarbonylhydrazones
3-[5′-Methyl-2′,4′-dihydro-1′,2′,4′-triazol-3′-on-4′-yl]iminoisatin
(0.010 mol) and hydrazine hydrate (0.012 mol) in water (15 mL)
was irradiated in the closed vessels with pressure control at 90 °C for
3 min (hold time) at 300 W maximum power. After the completion
(3a): M.p. 307–308 °C; IR (KBr): 3281, 3173 (NH), 1735, 1713
1
(C=O), 1675, 1612 (C=N) cm−1; H NMR: δ 1.48 (s, 3H, CH3),

270 JOURNAL OF CHEMICAL RESEARCH 2011
Table 1 Comparison of yields and time under microwave
δ 30.2 (CH2), 114.2, 115.7, 122.8, 126.4, 128.3, 129,5, 130.2, 133.1,
136.3 (ArC), 139.7 (C=N), 145.5 (C=N), 150.7 (C=O), 160.8 (C=O).
Anal. Calcd for C17H13N5O2: C, 63.94; H, 4.10; N, 21.93. Found: C,
63.95; H, 4.03; N, 22.04%.
3-[5′-(4′′-p-Chlorobenzyl)-2′,4′-dihydro-1′,2′,4′-triazol-3′-on-4′-
yl]iminoisatin (3e): M.p. 243–245 °C; IR (KBr): 3223, 3170 (NH),
1731, 1710 (C=O), 1611, 1588 (C=N) cm−1; 1H NMR: δ 3.99 (s, 2H,
CH2), 6.88–7.48 (m, 8H, ArH), 9.67 (s, 1H, NH), 11.88 (s, 1H, NH);
13C NMR: δ 29.0 (CH2), 113.3, 116.0, 120.4, 122.5, 126.4, 127.6,
128.9, 130.1, 131.5, 134.2, 140.3 (ArC), 138.0 (C=N), 144.8 (C=N),
148.7 (C=O), 159.6 (C=O). Anal. Calcd for C17H12ClN5O2: C, 57.72;
H, 3.42; N, 19.80. Found: C, 57.90; H, 3.35; N, 19.75%.
3-[5′-(4′′-p-Methylbenzyl)-2′,4′-dihydro-1′,2′,4′-triazol-3′-on-4′-
yl]iminoisatin (3f): M.p. 257–258 °C; IR (KBr): 3236, 3177 (NH),
1749, 1709 (C=O), 1610, 1587 (C=N) cm−1; 1H NMR: δ 2.14 (s, 3H,
CH3), 3.88 (s, 2H, CH2), 7.43–6.85 (m, 8H, ArH), 11.05 (s, 1H, NH),
12.09 (s, 1H, NH); 13C- NMR: δ 21.2 (CH3), 31.8 (CH2), 111.8, 115.1,
119.4, 120.5, 127.5, 129.6, 130.4, 134.6, 136.5 (ArC), 146.7 (C=N),
149.3 (C=N), 157.4 (C=O), 163.9 (C=O). Anal. Calcd for C18H15N5O2:
C, 64.86; H, 4.54; N, 21.01. Found: C, 64.81; H, 4.62; N, 20.88%.
3-[3′-(4′′-p-Methoxybenzyl)-4′,5′-dihydro-1′,2′,4′-triazol-5′-on-4′-yl]
iminoisatin (3g): M.p. 227–228 °C; IR (KBr): 3323, 3219 (NH), 1721,
1702 (C=O), 1611, 1576 (C=N) cm−1; 1H NMR: δ 3.62 (s, 3H, CH3),
3.81 (s, 2H, CH2), 6.83–8.02 (m, 8H, ArH), 9.56 (s, 1H, NH), 11.53
(s, 1H, NH); 13C NMR: δ 34.8 (CH2), 53.1 (OCH3), 112.6, 114.8,
115.1, 119.6, 120.7, 130.4, 132.5, 137.0 (ArC), 138.1 (C=N), 149.2
(C=O), 149.9 (C=N), 150.8 (Ar, C-OCH3), 164.1 (C=O). Anal. Calcd
for C18H15N5O3: C, 61.89; H, 4.33; N, 20.05. Found: C, 61.67; H, 4.31;
N, 20.13%.
irradiation and conventional heating
Compd
Yields /%
Oil bath
Time /min
MW
Oil bath
MW
3a
3b
3c
3d
3e
3f
86
73
81
69
74
82
77
70
82
62
82
79
66
73
90
79
84
80
75
88
91
76
87
74
90
92
76
88
300
300
300
300
300
300
300
240
240
240
240
240
240
240
5
5
5
5
5
5
5
3
3
3
3
3
3
3
3g
4a
4b
4c
4d
4e
4f
4g
6.89–7.46 (m, 4H, ArH), 11.09 (s, 1H, NH), 11.95 (s, 1H, NH); 13C
NMR: δ 12.2 (CH3), 111.8, 114.5 120.6, 121.4, 130.8, 144.9 (ArC),
146.8 (C=N), 149.3 (C=N), 156.9 (C=O), 164.2 (C=O). Anal. Calcd
for C11H9N5O2: C, 54.32; H, 3.73; N, 28.79. Found: C, 54.41; H, 3.71;
N, 28.71%.
3-[5′-Ethyl-2′,4′-dihydro-1′,2′,4′-triazol-3′-on-4′-yl]iminoisatin
(3b): M.p. 258–259 °C; IR (KBr): 3255, 3199 (NH), 1731, 1713.2
(C=O), 1615, 1594 (C=N) cm−1; 1H NMR: δ 1.02 (t, 3H, CH3, J=7.4),
2.64 (q, 2H, CH2, J=7.4), 8.39-7.12 (m, 4H, ArH), 11.69 (s, 1H, NH),
12.23 (s, 1H, NH); 13C NMR: δ 12.2 (CH3), 20.2 (CH2), 121.1, 124.6,
130.5, 141. 9 (ArC), 142.7 (C=N), 147.1 (C=N), 154.0 (C=O), 161.2
(C=O). Anal. Calcd for C12H11N5O2: C, 56.03; H, 4.31; N, 27.22.
Found: C, 55.96; H, 4.30; N, 27.28%.
3-[5′-Phenyl-2′,4′-dihydro-1′,2′,4′-triazol-3′-on-4′-yl]iminoisatin
(3c): M.p. 282–283 °C; IR (KBr): 3211, 3187 (NH), 1742, 1728
(C=O), 1614, 1585 (C=N) cm−1; 1H NMR: δ 7.81–6.98 (m, 9H, ArH),
11.14 (s, 1H, NH), 11.98 (s, 1H, NH); 13C NMR: δ 112.4, 116.6,
124.8, 128.9, 129.7, 130.7, 131.2, 132.4, 148.2 (ArC), 141.9 (C=N),
149.2 (C=N), 158.2 (C=O), 169.1 (C=O). Anal. Calcd for C16H11N5O2:
C, 62.95; H, 3.63; N, 22.94. Found: C, 62.87; H, 3.66; N, 22.98%.
3-[5′-Benzyl-2′,4′-dihydro-1′,2′,4′-triazol-3′-on-4′-yl]iminoisatin
(3d): M.p. 284–285 °C; IR (KBr): 3294, 3176 (NH), 1749, 1709
(C=O), 1610, 1582 (C=N) cm−1; 1H NMR: δ 4.04 (s, 2H, CH2), 7.08–
8.34 (m, 9H, ArH), 11.78 (s, 1H, NH), 12.37 (s, 1H, NH); 13C NMR:
3-[5′-Methyl-2′,4′-dihydro-1′,2′,4′-triazol-3′-on-4′-yl]imino-5-
nitroisatin (4a): M.p. 338–339 °C; IR (KBr): 3331, 3109 (NH), 1760,
1
1708 (C=O), 1626, 1603 (C=N), 1342, 1552 (NO2) cm−1; H NMR:
δ 2.25 (s, 3H, CH3), 7.10 (ddd, 1H, ArH, J=8.1, 2.3) 8.07 (dd, 1H,
ArH, J=2.3), 8.38 (dd, 1H, ArH, J=8.1), 11.41 (s, 1H, NH), 11.74 (s,
1H, NH); 13C NMR: δ 12.1 (CH3), 112.1, 120.3, 122.4, 143.3 (ArC),
144.2 (C=N), 149.2 (C=N), 150.5 (Ar, C-NO2), 154.2 (C=O), 158.4
(C=O). Anal. Calcd for C11H8N6O4: C, 45.84; H, 2.80; N, 29.16.
Found: C, 45.80; H, 2.77; N, 29.05%.
3-[5′-Ethyl-2′,4′-dihydro-1′,2′,4′-triazol-3′-on-4′-yl]imino-5-
nitroisatin (4b): M.p. 306–307 °C; IR (KBr): 3309, 3109 (NH), 1749,
1
1709 (C=O), 1601, 1583 (C=N), 1336, 1549 (NO2) cm−1; H NMR:
δ 1.82 (t, 3H, CH3, J=7.0), 2.96 (q, 2H, CH2, J=7.0), 7.24 (ddd, 1H,
ArH, J=8.4, 2.5), 8.04 (dd, 1H, ArH, J=2.5), 8.42 (dd, 1H, ArH,
J=8.4), 10.83 (s, 1H, NH), 11.36 (s, 1H, NH); 13C NMR: δ 11.8 (CH3),
22.3 (CH2), 114.1, 121.6, 122.9, 137.3 (ArC), 140.6 (C=N), 145.2
Table 2 Antimicrobial activity values of the compounds 3a–g and 4a–g
Compd
Microorganismsa and inhibition zone (mm) and MIC (µg mL−1)
Sa
Bs
Ec Pa Ca Cp
Cg
Ck
Zb
MC
Z
M
Z
M
Z
M
Z
M
Z
M
Z
M
Z
M
3a
9
13
12
–
62
500
62
1000
500
500
8
62
62
–
62
15
9
250
500
500
–
500
500
16
250
250
–
250
250
–
–
–
–
500
–
–
–
–
–
–
–
–
–
8
–
–
–
–
–
–
–
500
–
8
9
9
500
500
500
500
500
500
250
500
500
–
11
11
11
–
11
11
11
–
500
500
500
500
500
500
250
500
500
–
12
12
14
–
11
12
13
16
15
18
14
12
11
13
125
500
125
500
125
125
250
125
500
–
12
12
13
–
500
500
500
500
500
500
250
500
500
–
3b
3c
–
–
3e
–
9
9
17
16
17
–
15
13
9
–
–
–
–
3d
9
–
–
–
–
9
9
9
8
9
9
9
8
12
10
13
–
3f
9
–
–
3g
13
11
14
–
–
250
250
500
–
–
4a
–
250
500
–
4b
10
–
12
12
11
12
–
9
4c
12
10
14
13
13
4d
10
9
–
–
30
–
–
–
500
500
–
500
500
–
500
500
–
500
500
–
4e
125
–
500
0,8
–
–
–
4f
–
–
–
–
8
4g
9
25
250
1,6
–
–
–
500
12
500
500
500
Ampicillin
Fluconazole
18
0,9
–
18
0,3
20
0,3
16
1
22
0,13
a
Sa, Staphylococcus aureus; Bs, Bacillus subtilis; Ec, Escherichia coli; Pa, Pseudomonas aeruginosa; Ca, Candida albicans; Cp,
Candida parapsilosis; Cg, Candida glabrata; Ck, Candida kefyr.
b Z, zone diameter.
C M, MIC value

JOURNAL OF CHEMICAL RESEARCH 2011 271
(C=N), 147.1 (Ar, C-NO2), 150.3 (C=O), 160. 8 (C=O). Anal. Calcd
for C12H10N6O4: C, 47.69; H, 3.33; N, 27.81. Found: C, 47.61; H, 3.40;
N, 27.83%.
Ampicillin (10 µg) and fluconazole (5 µg) were used as the standard
drugs.
Secondly, quantitative inhibitory effects of the compounds were
evaluated by the broth micro-dilution method as described in
the guidelines of National Committee for Clinical Laboratory
Standards.28 To the first wells of rows of the plates, 100 µL of sub-
stance (4 mg mL−1) were added. After successive two-fold dilutions of
the compounds for each of the 12 rows of the 96-well flat-bottom
micro-dilution plates using MH broth and YEPD broth for the growth
of bacteria and Candida species respectively. One hundred microlitres
of the test organisms in MH broth andYEPD with inoculums adjusted
to ca 105 cfu mL−1 according to the Mac Farland turbidity standards29
were added to each well. This gave final concentrations of chemicals
and control drugs of 1000, 500, 250, 125, 62, 31, 16, 8, 4, 2, 1, and
0.5 µg mL−1, and the plates were incubated at 35 ºC for yeasts and
37 °C for bacteria for 18–24 hour. The minimum inhibitory concen-
tration (MIC) defined as the lowest concentration of the compounds
preventing visible growth was evaluated for all compounds. MH
broth and YEPD broth containing DMSO inoculated microorganisms
were used as the control.
3-[5′-Phenyl-2′,4′-dihydro-1′,2′,4′-triazol-3′-on-4′-yl]imino-5-
nitroisatin (4c): M.p. 318–319 °C; IR (KBr): 3267, 3121 (NH), 1733,
1
1705 (C=O), 1634, 1592 (C=N), 1355, 1541 (NO2) cm−1; H NMR:
δ 7.13–8.43 (m, 8H, ArH), 11.80 (s, 1H, NH), 12.44 (s, 1H, NH); 13
C
NMR: δ 113.2, 119.6, 120.5, 121.8, 128.5, 129.6, 131.4, 132.6, 136.3
(ArC), 142.3 (C=N), 144.1 (C=N), 145.2 (Ar, C-NO2), 151.3 (C=O),
162.1 (C=O). Anal. Calcd for C16H10N6O4: C, 54.86; H, 2.88; N, 23.99.
Found: C, 54.85; H, 2.85; N, 23.97%.
3-[5′-Benzyl-2′,4′-dihydro-1′,2′,4′-triazol-3′-on-4′-yl]imino-5-
nitroisatin (4d): M.p. 273–274 °C; IR (KBr): 3258, 3115 (NH), 1729,
1
1711 (C=O), 1626, 1588 (C=N), 1351, 1552 (NO2) cm−1; H NMR:
δ 3.72 (s, 2H, CH2), 7.13–8.43 (m, 8H, ArH), 11.80 (s, 1H, NH), 12.44
(s, 1H, NH); 13C NMR: δ 32.3 (CH2), 114.2, 118.4, 120.6, 121.4,
126.6, 128.4, 129.9, 131.7, 134.2 (ArC), 139.3 (C=N), 141.2 (C=N),
145.2 (Ar, C-NO2), 152.1 (C=O), 161.1 (C=O). Anal. Calcd for
C17H12N6O4: C, 56.05; H, 3.32; N, 23.07. Found: C, 56.01; H, 3.33; N,
23.10%.
3-[5′-(4′′-p-Chlorobenzyl)-2′,4′-dihydro-1′,2′,4′-triazol-3′-on-4′-yl]
imino-5-nitroisatin (4e): M.p. 262–263 °C; IR (KBr): 3285, 3125
(NH), 1744, 1709 (C=O), 1633, 1592 (C=N), 1351, 1549 (NO2) cm−1;
1H NMR: δ 3.42 (s, 2H, CH2), 7.10–8.44 (m, 7H, ArH), 11.47 (s, 1H,
NH), 12.41 (s, 1H, NH); 13C NMR: δ 32.9 (CH2), 116.8, 118.1, 120.0,
121.5, 127.4, 129.6, 131.7, 132.6, 138.0 (ArC), 139.3 (C=N), 141.2
(C=N), 147.0 (Ar, C-NO2), 149.9(C=O), 160.2 (C=O). Anal. Calcd for
C17H11ClN6O4: C, 51.20; H, 2.78; N, 21.08. Found: C, 51.13; H, 2.81;
N, 21.02%.
We are grateful to Osman Birol Özgümüş, Department of
Medical Microbiology, Faculty of Medicine, Rize University,
Rize, Turkey.
Received 5 January 2011; accepted 2 April 2011
Paper 1100510 doi: 10.3184/174751911X13043524455143
Published online: 1 June 2011
3-[5′-(4′′-p-Methylbenzyl)-2′,4′-dihydro-1′,2′,4′-triazol-3′-on-4′-
yl]imino-5-nitroisatin (4f): M.p. 296–297 °C; IR (KBr): 3205, 3144
(NH), 1743, 1702 (C=O), 1627, 1599 (C=N), 1352, 1547 (NO2) cm−1;
1H NMR: δ 2.21 (s, 3H, CH3), 3.96 (s, 2H, CH2), 7.04–7.12 (m, 4H,
ArH), 8.29–8.38 (m, 3H, ArH), 11.65 (s, 1H, NH), 11.94 (s, 1H, NH);
13C NMR: δ 21.3 (CH3), 31.6 (CH2), 113.3, 119.3, 121.1, 122.5, 128.4,
130.2, 131.9, 134.2, 143.3 (ArC), 146.2 (C=N), 149.1 (C=N), 150.4
(Ar, C-NO2), 154.1 (C=O), 158.2 (C=O). Anal. Calcd for C18H14N6O4:
C, 57.14; H, 3.73; N, 22.21. Found: C, 57.09; H, 3.70; N, 22.16%.
3-[5′-(4′′-p-Methoxybenzyl)-2′,4′-dihydro-1′,2′,4′-triazol-3′-on-4′-yl]
imino-5-nitroisatin (4g): M.p. 219–220 °C; IR (KBr): 3228, 3113
(NH), 1728, 1709 (C=O), 1624, 1589 (C=N), 1359, 1549 (NO2), cm−1;
1H NMR: δ 3.47 (s, 3H, CH3), 3.87 (s, 2H, CH2), 6.79–7.03 (m, 4H,
ArH), 7.59–8.52 (m, 3H, ArH), 11.21 (s, 1H, NH), 11.83 (s, 1H, NH);
13C NMR: δ 31.2 (CH2), 50.1 (OCH3), 114.3, 116.9, 120.6, 121.9,
122.7, 125.5, 130.1, 131.2 (ArC), 140.9 (C=N), 144.2 (C=N), 149.0
(Ar, C-NO2), 151.1 (Ar, C-OCH3), 153.6 (C=O), 157.7 (C=O). Anal.
Calcd for C18H14N6O5: C, 54.82; H, 3.58; N, 21.31. Found: C, 54.80;
H, 3.63; N, 21.305.
References
1
2
C.O. Kappe and D. Dallinger, Nature Rev. Drug Discovery, 2006, 5, 51.
A. Loupy, A. Petit, J. Hamelin, F. Texier-Boullet, P.Jacquault and D. Mathe,
Synthesis, 1998, 9, 1213.
3
4
R.S. Varma, Green Chem., 1999, 1, 43.
P. Lidström, J. Tierney, B. Wathey and J. Westman, Tetrahedron, 2001, 57,
9225.
5
6
7
R.S. Kumar, S.M. Rajesh, S. Perumal, D. Banerjee, P. Yogeeswari and
D. Sriram, Eur. J. Med. Chem., 2010, 45, 411.
T.R. Bal, B. Anand, P.Yogeeswari and D. Sriram, Bioorg. Med. Chem. Lett.,
2005, 15, 4451.
A. Andreani, S. Burnelli, M. Granaiola, A. Leoni, A. Locatelli, R. Morigi,
M. Rambaldi, L. Varoli, M.A. Cremonini, G. Placucci and R. Cervellati,
E. Greco, Eur. J. Med. Chem., 2010, 45, 1374.
8
9
R.P. Gupta and N.L. Narayana, Pharm Acta Helv. 1997, 72, 43.
Y. Teitz, D. Ronen, A. Vansover, T. Stematsky and J.L. Riggs, Antivir. Res.,
1994, 24, 305.
10 Y. Teitz, N. Barko, M. Abramoff and D. Ronen, Chemotherapy, 1994, 40,
195.
11 S.N. Pandeya, P. Yogeeswari, D. Sriram and G. Nath, Boll. Chim. Farm.,
1998b, 137, 321.
12 O.G. Todoulou,; A.E. Papadaki-Valiraki, S. Ikeda and E.D. Clercq, Eur. J.
Med. Chem., 1994, 29, 611.
13 S. Rollas, N. Kalyoncuoglu, D. Sur-Altiner and Y. Yegenoglu, Pharmazie,
1993, 48, 308.
14 F. Malbec, R. Milcent and P.J. Vicart, Heterocycl. Chem., 1984, 21, 1769.
15 B. Kahveci and A.A. Ikizler, Acta Pol. Pharm. Drug Res., 2000, 57,
119.
16 O. Bekircan, B. Kahveci and M. Küçük Turk J. Chem., 2006, 30, 29.
17 B. Kahveci, M. Özil andM. Serdar, Heteroatom Chem., 2008, 19, 38.
18 M. Özil, F. İslamoğlu, E. Menteşe and B. Kahveci, Helv. Chim. Acta., 2010,
93, 1967.
19 C.O. Kappe, D. Dallinger and S. Murphree, Practical microwave synthesis
for organic chemists, Wiley, VCH, Weinheim, 2009.
20 D. Michael, P. Mingos and D.R. Baghurst, Chem. Soc. Rev., 1991, 20, 1.
21 P. Lidstrom, J. Tierney, B. Wathey and J. Westman, Tetrahedron, 2001, 57,
9225.
Antibacterial and antifungal activity assays
The chemical compounds 3a–g and 4a–g were dissolved in dimethyl
sulfoxide (DMSO) for in vitro antimicrobial activity assays. The
compounds were tested for antimicrobial effect against four bacterial
strains, Escherichia coli ATCC 25922, Pseudomonas aeruginosa
ATCC 27853, Staphylococcus aureus ATCC 25923 and Bacillus
subtilis ATCC 6633 and four yeast strains, Candida albicans ATCC
60193, Candida parapsilosis ATCC 22019, Candida kefyr ATCC
46764 and Candida glabrata ATCC 66032. The standard strains were
obtained from and tests were performed in the Biotest Laboratory,
Department of Microbiology and Clinical Microbiology, Faculty of
Medicine of Karadeniz Technical University in Turkey.
Antimicrobial activity tests were performed by using two tech-
niques. First, the agar-well diffusion method 27 was used. Each micro-
organism was suspended in Mueller–Hinton (MH) broth (Difco, USA)
and diluted to ca 105 colony forming unit (cfu) per ml. For Candida
species, yeast extract peptone dextrose (YEPD) broth (yeast extract
1%, peptone 2%, dextrose 2%) medium were used. They were flood-
inoculated onto the surface of MH agar and Saboraud dextrose agar
(Difco, USA) and then dried. Six millimetre diameter wells were
cut from the agars using a sterile cork-borer, and 1000 µg/100 µl of
the chemical substances were delivered into the wells. The plates
were incubated for 18 h at 35 °C. Antimicrobial activity was evaluated
by measuring the zone of inhibition against the test organisms.
22 M. Alam, M. Younas, M.A. Zafar and P. Naem, J. Sci Ind. Res., 1989, 32,
246.
23 L.W. Parks, W.M. Casey, R. Prasad and M. Ghannoum, eds, Lipids of
pathogenic fungi, CRC Press, Inc., Boca Raton, 63, 1996.
24 A.A. İkizler and R. Ün, Chem. Acta Turc., 1979, 7, 269.
25 R. Milcent and C.J. Redeuilh, Heterocycl. Chem., 1979, 16, 403.
26 B. Kahveci, Molecules, 2005, 10, 376.
27 A. Sokmen, B.M. Jones and M. Ertürk, Ethnopharmacology, 1999, 67,
79.
28 National Committee for Clinical Laboratory Standards, 1997.
29 V. Lorian, Antibiotics in laboratory medicine, 2nd edn, Williams & Wilkins,
London, 116, 1986.

Copyright of Journal of Chemical Research is the property of Science Reviews 2000 Ltd. and its content may
not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written
permission. However, users may print, download, or email articles for individual use.