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Studies on clinically important nitrogen and sulphur containing heterocyclic compounds
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SECTION-A
SPECTROSCOPIC ANALYSIS OF SYNTHESIZED COMPOUNDS
Newly synthesized compounds were characterized by IR, 1H NMR, 13C NMR and
mass spectral data as follows.
Part-I, Series-3
The structure of the final derivative GK3-7 was established on the basis of their
spectroscopic data. For example, the IR spectra of compound (GK3-7) showed
characteristic absorption band of carbonyl group at 1687 cm-1, while vibrations
appeared at 3071, 3029 and 2924 cm-1 corresponding to C-H stretching of
aromatic, -CH=CH- and –CH3 groups respectively. Absorption displayed at 745
cm-1 was due to C-Cl stretching vibrations, while C-O-C stretching vibration in
oxadiazole ring appeared at 1228 cm-1. Strong absorption band displayed at 3397
cm-1 was characteristic of secondary amine (N-H) stretching in benzimidazole
ring. 1H NMR spectrum of compound GK3-7 showed two doublets at δ 6.61 and
7.94 ppm due to the protons of alkene carbons attached to carbonyl group and 3-
chlorophenyl respectively. Secondary amine proton displayed chemical shift value
at δ 9.84 ppm as a singlet and remaining twelve protons revealed multiplet
between δ 7.22-7.84 ppm. Two singlets observed at δ 1.88 and 2.38 ppm
integrating for six protons of two methyl groups attached to oxadiazole ring and
phenyl ring respectively. 13C NMR spectrum of compound GK3-7, carbon atom of
carbonyl group and methine carbon (asymmetric carbon) appeared at δ 166.8
and 90.6 ppm respectively. Two signals displayed at δ 118.6 and 141.9 ppm were
characteristics of alkene carbons attached to carbonyl and 3-chlorophenyl groups
respectively. Two methyl carbons revealed chemical shifts at δ 21.4 and 27.8 ppm
whereas carbon of chlorine group showed chemical shift value at δ 134.1 ppm.
The mass spectrum of GK3-7 showed molecular ion peak at m/z = 457.44 (M+)
along with other fragment ion peaks, which is in agreement with its proposed
structure. All the synthesized compounds were fully characterized by
spectroscopic methods and gave satisfactory analytical and spectral data.
Structure of compound (GK3-7) is described in the following Figure A.
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CHARACTERIZATION OF 1-(2-(1H-BENZO[d]IMIDAZOL-2-YL)-2-METHYL-5-(P-TOLYL)-1,3,4-OXADIAZOL-3(2H)-YL)-3-(3-CHLOROPHENYL)PROP-2-EN-1-
ONE (GK3-7)
The IR spectral assignments (Figure-1)
No. Wave number (cm-1) Assignment 1 3397 N-H Stretching (2º amine) 2 3071, 3029 C-H stretching, aromatic ring, -CH=CH- 3 2924 C-H stretching, -CH3 4 1687 >C=O stretching 5 1554, 1438 >C=N-, >C=C< stretching 6 1228 C-O-C stretching, oxadiazole ring 7 745 C-Cl stretching
Assignment of 1H NMR chemical shifts (δ ppm) to different protons (Figure-2)
No. Chemical shift (δ ppm) Multiplicity Proton assignment No. of
protons
1 1.88 Singlet -CH3 of oxadiazole ring 3 2 2.38 Singlet -CH3 of phenyl ring 3 3 6.61 Doublet =CH-CO- 1 4 7.22-7.80 Multiplet Ar-H 12 5 7.94 Doublet =CH-Ar 1 6 9.64 Singlet N-H of benzimidazole ring 1
Assignment of 13C NMR chemical shifts (δ ppm) to different carbons (Figure-3)
21.4, 27.8, 90.6, 115.1 (2), 118.6, 123.2 (2), 125.6 (2), 126.1, 126.7, 128.1,
129.2 (2), 129.7, 130.2, 134.1, 136.7, 138.8 (2), 140.8, 141.4, 141.9, 157.2,
166.8
Proposed fragmentation pattern (LCMS) (Figure-4)
No. m/z Relative intensity % Ion
1 457.44 42% (M+) C26H21ClN4O2
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Figure 1
Figure 2
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Figure 3
m/z60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600
%
0
100GK5-VII P 2 (0.037) 1: TOF MS ES+
1.15e3479.40
139.20
83.12
70.08
135.12
119.1393.09
439.41
331.27
309.29
199.20
140.20
175.18141.11
274.41241.23
239.20
217.21 242.23
291.27381.33
365.32342.31
437.38
398.37421.38
457.44
458.43
571.54
571.36
549.51
531.49480.41
495.39
529.46
550.51
551.53
572.54
587.47591.54
597.54
Figure 4
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CHARACTERIZATION OF 1-(2-(1H-BENZO[d]IMIDAZOL-2-YL)-5-(4-CHLORO- PHENYL)-2-METHYL-1,3,4-OXADIAZOL-3(2H)-YL)-3-PHENYLPROP-2-EN-1-
ONE (GK1-4)
The IR spectral assignments (Figure-5)
No. Wave number (cm-1) Assignment 1 3397 N-H Stretching (2º amine) 2 3071, 3029 C-H stretching, aromatic ring, -CH=CH- 3 2924 C-H stretching, -CH3 4 1686 >C=O stretching 5 1513, 1438 >C=N-, >C=C< stretching 6 1228 C-O-C stretching, oxadiazole ring 7 741 C-Cl stretching
Assignment of 1H NMR chemical shifts (δ ppm) to different protons (Figure-6)
No. Chemical shift (δ ppm) Multiplicity Proton assignment No. of
protons
1 1.86 Singlet -CH3 of oxadiazole ring 3 2 6.58 Doublet =CH-CO- 1 3 7.18-7.81 Multiplet Ar-H 13 4 7.98 Doublet =CH-Ar 1 5 9.88 Singlet N-H of benzimidazole ring 1
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Figure 5
Figure 6
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CHARACTERIZATION OF 1-(2-(1H-BENZO[d]IMIDAZOL-2-YL)-5-(4-CHLORO- PHENYL)-2-METHYL-1,3,4-OXADIAZOL-3(2H)-YL)-3-(2-CHLOROPHENYL)-
PROP-2-EN-1-ONE (GK2-4)
The IR spectral assignments (Figure-7)
No. Wave number (cm-1) Assignment 1 3367 N-H Stretching (2º amine) 2 3066, 3024 C-H stretching, aromatic ring, -CH=CH- 3 2940 C-H stretching, -CH3 4 1691 >C=O stretching 5 1548, 1488 >C=N-, >C=C< stretching 6 1232 C-O-C stretching, oxadiazole ring 7 746 C-Cl stretching
Assignment of 1H NMR chemical shifts (δ ppm) to different protons (Figure-8)
No. Chemical shift (δ ppm) Multiplicity Proton assignment No. of
protons
1 1.89 Singlet -CH3 of oxadiazole ring 3 2 6.61 Doublet =CH-CO- 1 3 7.16-7.78 Multiplet Ar-H 12 4 8.02 Doublet =CH-Ar 1 5 9.86 Singlet N-H of benzimidazole ring 1
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Figure 7
Figure 8
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CHARACTERIZATION OF 1-(2-(1H-BENZO[d]IMIDAZOL-2-YL)-5-(4-CHLORO- PHENYL)-2-METHYL-1,3,4-OXADIAZOL-3(2H)-YL)-3-(4-CHLOROPHENYL)-
PROP-2-EN-1-ONE (GK4-4)
The IR spectral assignments (Figure-9)
No. Wave number (cm-1) Assignment 1 3357 N-H Stretching (2º amine) 2 3074, 3027 C-H stretching, aromatic ring, -CH=CH- 3 2947 C-H stretching, -CH3 4 1690 >C=O stretching 5 1557, 1492 >C=N-, >C=C< stretching 6 1238 C-O-C stretching, oxadiazole ring 7 756 C-Cl stretching
Assignment of 1H NMR chemical shifts (δ ppm) to different protons (Figure-10)
No. Chemical shift (δ ppm) Multiplicity Proton assignment No. of
protons
1 1.85 Singlet -CH3 of oxadiazole ring 3 2 6.57 Doublet =CH-CO- 1 3 7.23-7.81 Multiplet Ar-H 12 4 8.03 Doublet =CH-Ar 1 5 9.88 Singlet N-H of benzimidazole ring 1
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Figure 9
Figure 10
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CHARACTERIZATION OF 1-(2-(1H-BENZO[d]IMIDAZOL-2-YL)-5-(4-METHOXY- PHENYL)-2-METHYL-1,3,4-OXADIAZOL-3(2H)-YL)-3-(4-HYDROXYPHENYL)-
PROP-2-EN-1-ONE (GK5-12)
The IR spectral assignments (Figure-11)
No. Wave number (cm-1) Assignment 1 3447 O-H Stretching 2 3398 N-H Stretching (2º amine) 3 3071, 3029 C-H stretching, aromatic ring, -CH=CH- 4 2923, 2854 C-H stretching, -CH3, -OCH3 5 1666 >C=O stretching 6 1523, 1492 >C=N-, >C=C< stretching 7 1229 C-O-C stretching, oxadiazole ring
Assignment of 1H NMR chemical shifts (δ ppm) to different protons (Figure-12)
No. Chemical shift (δ ppm) Multiplicity Proton assignment No. of
protons
1 1.84 Singlet -CH3 of oxadiazole ring 3 2 3.86 Singlet -OCH3 of phenyl ring 3 3 6.46 Doublet =CH-CO- 1 4 7.20-7.81 Multiplet Ar-H 12 5 7.92 Doublet =CH-Ar 1 6 9.14 Singlet O-H of phenyl ring 1 7 9.82 Singlet N-H of benzimidazole ring 1
Proposed fragmentation pattern (LCMS) (Figure-13)
No. m/z Relative intensity % Ion
1 455.47 82% (M+) C26H22N4O4
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Figure 11
Figure 12
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m/z60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600
%
0
100GK5-VII N 3 (0.056) 1: TOF MS ES-
7.93e3307.31
215.23
173.22111.0687.0762.03 121.12137.13
214.83
216.25
251.24217.26 283.30
455.47
357.38
308.34
311.33
340.36339.40
358.40437.48
413.46393.39 435.45
547.56
456.50
505.54473.51
529.56
548.58
573.60572.52 589.61 597.63
Figure 13
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Part-II, Series-1
The structure of the final derivative GK6-1 was established on the basis of their
spectroscopic data. For example, the IR spectra of compound GK6-1 showed
characteristic absorption band of carbonyl group at 1693 cm-1. Absorption bands
at 1517 and 1582 cm-1 were due to stretching vibrations corresponding to C=C
and C=N groups respectively. Strong absorption band displayed at 1222 cm-1 was
characteristic of C-O-C stretching in oxadiazole ring. Compound endowed with
chloro group appeared vibration at 756 cm-1, while absorption bands appeared at
3158 and 3017 cm-1 corresponding to C-H stretching of aromatic and -CH=CH-
groups respectively. 1H NMR spectrum of compound GK6-1 showed two doublets
at δ 6.52 and 7.96 ppm due to the protons of alkene carbons attached to
carbonyl group and phenyl ring respectively. Two singlets observed at δ 6.84 and
8.23 ppm integrating for one proton attached to asymmetric carbon and one
pyrazole ring proton (C5-H) respectively. Two doublets appeared at δ 8.14 and
8.78 ppm for four protons of pyridine ring (C3-H & C5-H; C2-H & C6-H) and
remaining fourteen protons displayed multiplet between δ 7.34-7.86 ppm. 13C
NMR spectrum of compound GK6-1, carbon atom of carbonyl group and methine
carbon (asymmetric carbon) appeared at δ 167.2 and 78.8 ppm respectively. Two
carbons of alkene group appeared chemical shifts at δ 141.8 and 118.9 ppm due
to carbon attached to phenyl ring and carbonyl group respectively whereas
carbon of chlorine group showed chemical shift value at δ 134.4 ppm. The mass
spectrum of GK6-1 showed molecular ion peak at m/z = 531.12 (M+), along with
other fragment ion peaks, which is in agreement with its proposed structure. All
synthesized compounds were fully characterized by spectroscopic methods and
gave satisfactory analytical and spectral data. Structure of compound (GK6-1) is
described in the following Figure B.
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CHARACTERIZATION OF 1-(2-(3-(4-CHLOROPHENYL)-1-PHENYL-1H-PYRA- ZOL-4-YL)-5-(PYRIDIN-4-YL)-1,3,4-OXADIAZOL-3(2H)-YL)-3-PHENYLPROP-2-
EN-1-ONE (GK6-1)
The IR spectral assignments (Figure-14)
No. Wave number (cm-1) Assignment 1 3158, 3017 C-H stretching, aromatic ring, -CH=CH- 2 1693 >C=O stretching 3 1582, 1517 >C=N-, >C=C< stretching 4 1222 C-O-C stretching, oxadiazole ring 5 756 C-Cl stretching
Assignment of 1H NMR chemical shifts (δ ppm) to different protons (Figure-15)
No. Chemical shift (δ ppm) Multiplicity Proton assignment No. of
protons 1 6.40 Doublet =CH-CO- 1 2 6.84 Singlet C2-H oxadiazole ring 1 3 7.14-7.78 Multiplet Ar-H 14 4 7.96 Doublet =CH-Ar 1 5 8.14 Doublet C3-H & C5-H pyridine ring 2 6 8.23 Singlet C5-H pyrazole ring 1 7 8.78 Doublet C2-H & C6-H pyridine ring 2
Assignment of 13C NMR chemical shifts (δ ppm) to different carbons (Figure-16)
78.8, 117.2, 118.9, 119.8 (2), 123.2, 124.2 (2), 126.2, 127.8, 128.0 (2), 128.5
(2), 128.9 (2), 129.2 (2), 129.8 (2), 131.2, 134.4, 135.1, 138.5, 139.8, 141.8,
149.3 (2), 149.8, 157.1, 167.2
Proposed fragmentation pattern (LCMS) (Figure-17)
No. m/z Relative intensity % Ion 1 531.12 100% (M+) C31H22ClN5O2
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Figure 14
Figure 15
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Figure 16
Figure 17
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CHARACTERIZATION OF 1-(2-(3-(4-FLUOROPHENYL)-1-PHENYL-1H-PYRA- ZOL-4-YL)-5-(PYRIDIN-4-YL)-1,3,4-OXADIAZOL-3(2H)-YL)-3-PHENYLPROP
-2-EN-1-ONE (GK7-1)
The IR spectral assignments (Figure-18)
No. Wave number (cm-1) Assignment
1 3166 C-H stretching, aromatic ring, -CH=CH- 2 3028 C-H stretching, -CH=CH- 3 1694 >C=O stretching 4 1592, 1528 >C=N-, >C=C< stretching 5 1232 C-O-C stretching, oxadiazole ring 6 1152 C-F stretching
Assignment of 1H NMR chemical shifts (δ ppm) to different protons (Figure-19)
No. Chemical shift (δ ppm) Multiplicity Proton assignment No. of
protons
1 6.51 Doublet =CH-CO- 1 2 6.84 Singlet C2-H oxadiazole ring 1 3 7.20-7.82 Multiplet Ar-H 14 4 8.03 Doublet =CH-Ar 1 5 8.20 Doublet C3-H & C5-H pyridine ring 2 6 8.34 Singlet C5-H pyrazole ring 1 7 8.86 Doublet C2-H & C6-H pyridine ring 2
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Figure 18
Figure 19
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CHARACTERIZATION OF 1-(2-(3-(4-METHOXYPHENYL)-1-PHENYL-1H-PYRA- ZOL-4-YL)-5-(PYRIDIN-4-YL)-1,3,4-OXADIAZOL-3(2H)-YL)-3-PHENYLPROP-2-
EN-1-ONE (GK8-1)
The IR spectral assignments (Figure-20)
No. Wave number (cm-1) Assignment
1 3142 C-H stretching, aromatic ring, -CH=CH- 2 3016 C-H stretching, -CH=CH- 3 2832 C-H stretching, -OCH3 4 1682 >C=O stretching 5 1572, 1512 >C=N-, >C=C< stretching 6 1212 C-O-C stretching, oxadiazole ring
Assignment of 1H NMR chemical shifts (δ ppm) to different protons (Figure-21)
No. Chemical shift (δ ppm) Multiplicity Proton assignment No. of
protons
3.81 Singlet -OCH3 3 1 6.40 Doublet =CH-CO- 1 2 6.80 Singlet C2-H oxadiazole ring 1 3 7.15-7.80 Multiplet Ar-H 14 4 7.88 Doublet =CH-Ar 1 5 8.06 Doublet C3-H & C5-H pyridine ring 2 6 8.21 Singlet C5-H pyrazole ring 1 7 8.75 Doublet C2-H & C6-H pyridine ring 2
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Figure 20
Figure 21
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CHARACTERIZATION OF 1-(2-(3-(4-NITROPHENYL)-1-PHENYL-1H-PYRAZOL-4-YL)-5-(PYRIDIN-4-YL)-1,3,4-OXADIAZOL-3(2H)-YL)-3-PHENYLPROP-2-EN-1-
ONE (GK9-1)
The IR spectral assignments (Figure-22)
No. Wave number (cm-1) Assignment
1 3167 C-H stretching, aromatic ring, -CH=CH- 2 3036 C-H stretching, -CH=CH- 3 1693 >C=O stretching 4 1588, 1532 >C=N-, >C=C< stretching 5 1512 N=O stretching, -NO2 6 1232 C-O-C stretching, oxadiazole ring
Assignment of 1H NMR chemical shifts (δ ppm) to different protons (Figure-23)
No. Chemical shift (δ ppm) Multiplicity Proton assignment No. of
protons
1 6.44 Doublet =CH-CO- 1 2 6.80 Singlet C2-H oxadiazole ring 1 3 7.18-7.82 Multiplet Ar-H 14 4 7.98 Doublet =CH-Ar 1 5 8.24 Doublet C3-H & C5-H pyridine ring 2 6 8.31 Singlet C5-H pyrazole ring 1 7 8.81 Doublet C2-H & C6-H pyridine ring 2
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Figure 22
Figure 23
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Part-III, Series-1 Structure of compound (GK10-1) was confirmed on the basis of spectral data. For
example, the IR spectra of compound (GK10-1) showed absorption bands at 3163
and 2931 cm-1 characteristic of C-H stretching of aromatic ring and alkyl chain
respectively. Absorption reported at 752 cm-1 was due to C-Cl stretching
vibrations, while cyanide group stretching vibration appeared at 2281 cm-1.
Strong absorption band displayed at 3393 cm-1 was characteristic of secondary
amine (N-H) stretching in pyrimidine ring. Absorption bands at 1541 and 1496
cm-1 were due to stretching vibrations corresponding of C=N and C=C groups
respectively. 1H NMR spectrum of compound (GK10-1) displayed two triplets at δ
3.11 and 3.42 ppm due to protons of two methylene groups attached to cyanide
group and sulphur atom respectively. Two doublets appeared at δ 5.11 and 6.32
ppm corresponding to protons attached to asymmetric carbon and methine
carbon of pyrimidine ring respectively. Secondary amine proton displayed
chemical shift value at δ 9.61 ppm as a singlet and remaining nine protons
appeared multiplet between δ 7.42-8.26 ppm. 13C NMR spectrum of compound
(GK10-1) revealed twenty nonequivalent carbons. Two different methylene carbons
appeared at δ 47.9 and 54.6 ppm, while cyanide group carbon displayed
chemical shift value at δ 119.2 ppm. The appearance of signal around at δ 166.6
ppm was assignable to carbon of pyrimidine ring attached to two nitrogen and a
sulphur atoms. Two signals displayed at δ 132.7 and 152.2 ppm were
characteristics of carbons of quinoline ring attached to chlorine atom whereas
assymetric carbon of pyrimidine revealed chemical shift at δ 48.4 ppm. The mass
spectrum of GK10-1 showed molecular ion peak at m/z = 439.42 (M+) along with
other fragment ion peaks, which is in agreement with its proposed structure. All
synthesized compounds were fully characterized by spectroscopic methods and
gave satisfactory analytical and spectral data. Structure of compound (GK10-1) is
described in the following Figure C.
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CHARACTERIZATION OF 3-((6-(2,6-DICHLOROQUINOLIN-3-YL)-4-PHENYL-1,6-DIHYDROPYRIMIDIN-2-YL)THIO)PROPANENITRILE (GK10-1)
The IR spectral assignments (Figure-24)
No. Wave number (cm-1) Assignment
1 3393 N-H stretching, pyrimidine ring 2 3163 C-H stretching, aromatic ring, alkyl chain 3 2931 C-H stretching, alkyl chain 4 2281 -C≡N stretching, nitrile group 5 1541 >C=N-stretching 6 1496 >C=C< stretching 7 752 C-Cl stretching
Assignment of 1H NMR chemical shifts (δ ppm) to different protons (Figure-25)
No. Chemical
shift (δ ppm)
Multiplicity Proton assignment No. of protons
1 3.11 Triplet -CH2-CN 2 2 3.42 Triplet -CH2-S- 2 3 5.11 Doublet H-C-NH- (asymmetric carbon) 1 4 6.32 Doublet H-C=C-N (olefinic carbon) 1 5 7.20-8.20 Multiplet Ar-H 9 6 9.61 Singlet H-N< (2º amine) 1
Assignment of 13C NMR chemical shifts (δ ppm) to different carbons (Figure-26)
47.9, 48.4, 54.6, 114.1, 119.2, 123.5, 126.4 (2), 127.2, 127.8, 128.4 (2), 128.9,
131.6, 132.1, 132.7, 135.2, 136.8, 142.2, 143.7, 152.2, 166.6
Proposed fragmentation pattern (LCMS) (Figure-27)
No. m/z Relative intensity % Ion
1 439.42 100% (M+) C22H16Cl2N4S
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Figure 24
Figure 25
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Figure 26
Figure 27
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CHARACTERIZATION OF 3-((6-(2-CHLORO-6-FLUOROQUINOLIN-3-YL)-4-(4-CHLOROPHENYL)-1,6-DIHYDROPYRIMIDIN-2-YL)THIO)PROPANENITRILE
(GK11-4)
The IR spectral assignments (Figure-28)
No. Wave number (cm-1) Assignment 1 3381 N-H stretching, pyrimidine ring 2 3144 C-H stretching, aromatic ring 3 2920 C-H stretching, alkyl chain 4 2266 -C≡N stretching, nitrile group 5 1566 >C=N-stretching 6 1515 >C=C< stretching 7 1113 C-F stretching 8 766 C-Cl stretching
Assignment of 1H NMR chemical shifts (δ ppm) to different protons (Figure-29)
No. Chemical shift (δ ppm) Multiplicity Proton assignment No. of
protons
1 3.15 Triplet -CH2-CN 2 2 3.51 Triplet -CH2-S- 2 3 5.18 Doublet H-C-NH- (asymmetric carbon) 1 4 6.12 Doublet H-C=C-N (olefinic carbon) 1 5 7.18-8.21 Multiplet Ar-H 8 6 9.72 Singlet H-N< (2º amine) 1
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Figure 28
Figure 29
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CHARACTERIZATION OF 3-((6-(2-CHLORO-6-METHOXYQUINOLIN-3-YL)-4-(4- CHLORO-PHENYL)-1,6-DIHYDROPYRIMIDIN-2-YL)THIO)PROPANENITRILE
(GK12-4)
The IR spectral assignments (Figure-30)
No. Wave number (cm-1) Assignment 1 3413 N-H stretching, pyrimidine ring 2 3192 C-H stretching, aromatic ring 3 2947 C-H stretching, alkyl chain 4 2829 C-H stretching, -OCH3 5 2314 -C≡N stretching, nitrile group 6 1528 >C=N-stretching 7 1481 >C=C< stretching 8 734 C-Cl stretching
Assignment of 1H NMR chemical shifts (δ ppm) to different protons (Figure-31)
No. Chemical shift (δ ppm) Multiplicity Proton assignment No. of
protons
1 3.12 Triplet -CH2-CN 2 2 3.46 Triplet -CH2-S- 2 3 3.87 Singlet -OCH3 3 4 5.17 Doublet H-C-NH- (asymmetric carbon) 1 5 6.11 Doublet H-C=C-N (olefinic carbon) 1 6 7.21-8.18 Multiplet Ar-H 8 7 9.62 Singlet H-N< (2º amine) 1
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Figure 30
Figure 31
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SECTION-B
BIOLOGICAL EVALUATION OF SYNTHESIZED COMPOUNDS
Introduction
Antimicrobial agents are among the most commonly used and misused of all
drugs. The inevitable consequence of the widespread use of antimicrobial agents
has been the emergence of antibiotic-resistant pathogens, fueling an ever-
increasing need for new drugs. However, the pace of antimicrobial drug
development has slowed dramatically, with only a handful of new agents, few of
which are novel, being introduced into clinical practice each year. Reducing
inappropriate antibiotic use is thought to be the best way to control resistance.
Although awareness of the consequences of antibiotic misuse is increasing,
overprescribing remains widespread, driven largely by patient demand, time
pressure on clinicians, and diagnostic uncertainty. If the gains in the treatment
of infectious diseases are to be preserved, clinicians must be wiser and more
selective in the use of antimicrobial agents.
The history of chemotherapeutic agents1
Bacteria were first identified in the 1670s by van Leeuwenhoek, following his
invention of the microscope. However, it was not until the nineteenth century
that their link with disease was appreciated. This appreciation followed the
elegant experiments carried out by the French scientist Pasteur, who
demonstrated that specific bacterial strains were crucial to fermentation and that
these and other microorganisms were far more widespread than was previously
thought. The possibility that these microorganisms might be responsible for
disease began to take hold.
An early advocate of a 'germ theory of disease' was the Edinburgh surgeon Lister.
Despite the protests of several colleagues who took offence at the suggestion that
they might be infecting their own patients, Lister introduced carbolic acid as an
antiseptic and sterilizing agent for operating theatres and wards. The
improvement in surgical survival rates was significant.
During that latter half of the nineteenth century, scientists such as Koch were
able to identify the microorganisms responsible for diseases such as tuberculosis,
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cholera, and typhoid. Methods such as vaccination for fighting infections were
studied. Research was also carried out to try and find effective antibacterial
agents or antibiotics. However, the scientist who can lay claim to be the father of
chemotherapy-the use of chemicals against infection—was Paul Ehrlich. Ehrlich
spent much of his career studying histology, then immunochemistry, and won a
Nobel prize for his contributions to immunology. However, in 1904 he switched
direction and entered a field which he defined as chemotherapy. Ehrlich's
'Principle of Chemotherapy' was that a chemical could directly interfere with the
proliferation of microorganisms, at concentrations tolerated by the host. This
concept was popularly known as the 'magic bullet', where the chemical was seen
as a bullet which could search out and destroy the invading microorganism
without adversely affecting the host. The process is one of selective toxicity,
where the chemical shows greater toxicity to the target microorganism than to
the host cells. Such selectivity can be represented by a 'chemotherapeutic index',
which compares the minimum effective dose of a drug with the maximum dose
which can be tolerated by the host. This measure of selectivity was eventually
replaced by the currently used therapeutic index.
By 1910, Ehrlich had successfully developed the first example of a purely
synthetic antimicrobial drug. This was the arsenic-containing compound
‘salvarsan’ (Figure 1). Although it was not effective against a wide range of
bacterial infections, it did prove effective against the protozoal disease sleeping
sickness (trypanosomiasis) and the spirochaete disease of syphilis. The drug was
used until 1945 when it was replaced by penicillin.
Over the next twenty years, progress was made against a variety of protozoal
diseases, but little progress was made in finding antibacterial agents, until the
introduction of ‘proflavine’ (Figure 1) in 1934. It is an interesting drug since it
targets bacterial DNA rather than protein. Despite the success of this drug, it was
not effective against bacterial infections in the bloodstream and there was still an
urgent need for agents which would fight these infections.
This need was answered in 1935 with the discovery that a red dye called
‘prontosil’ (Figure 1) was effective against streptococci infections in vivo. As
discussed later, prontosil was eventually recognized as being a prodrug for a new
class of antibacterial agents-the sulfa drugs (sulfonamides). The discovery of
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these drugs was a real breakthrough, since they represented the first drugs to be
effective against bacterial infections carried in the bloodstream. They were the
only effective drugs until penicillin became available in the early 1940s.
Although penicillin was discovered in 1928, it was not until 1940 that effective
means of isolating it were developed by Florey and Chain. Society was then
rewarded with a drug which revolutionized the fight against bacterial infection
and proved even more effective than the sulfonamides. Many antibacterial agents
are now available and the vast majority of bacterial diseases such as syphilis,
tuberculosis, typhoid, bubonic plague, leprosy, diphtheria, gas gangrene,
tetanus, gonorrhea have been brought under control. This represents a great
achievement for medicinal chemistry and it is perhaps sobering to consider the
hazards which society faced in the days before penicillin.
Bacteria are unicellular microorganisms. They are typically a few micrometers
long and have many shapes including spheres, rods and spirals. Microorganisms
have played profound roles in warfare, religion and the migration of populations.
Control of microbial population is necessary to prevent transmission of diseases,
infection, decomposition, contamination and spoilage caused by them.2 Man’s
personal comforts and convenience depend to a large extent on the control of
microbial population.
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Bacteria
Bacteria are a successful and ancient form of life, quite different from the
eukaryotes (which include the fungi, plants and animals). They are small cells,
found in the environment as either individual cells or aggregated together as
clumps, and their intracellular structure is far simpler than eukaryotes.
Bacteria have a single circular DNA chromosome that is found within the
cytoplasm of the cell as they do not have a nucleus. Indeed they lack any of the
intracellular organelles so characteristic of eukaryotic cells, such that they do not
have the golgi apparatus, endoplasmic reticulum, lysosomes nor mitochondria.
However they are generally capable of ‘free-living’ and therefore they possess all
the biosynthetic machinery that is needed for this, including 70S ribosomes (as
opposed to the larger 80S forms found in eukaryotes) distributed throughout the
cytoplasm.
The most complex region of the cell is often the cell surface. The cell wall/outer
membrane is described below, but in addition some bacteria may secrete a
polysaccharide capsule onto their outer surface, some may have flagella which
they require for mobility and some may have external projections such as
fimbriae and pili which are useful for adherence in their chosen habitat.
Although bacteria are generally far simpler than eukaryotic cells, they are
extremely efficient within their own little niche - and this may include the ability
to cause human infections. Bacteria multiply by binary fission and there is no
sexual interaction.3
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Unlike animals and other eukaryotes, bacterial cells do not contain a nucleus or
other membrane-bound organelles. Although the term bacteria traditionally
included all prokaryotes, the scientific nomenclature changed after the discovery
that prokaryotic life consists of two very different groups of organisms that
evolved independently from an ancient common ancestor. These evolutionary
domains are called Bacteria and Archaea.4
The study of the biology of bacteria requires some knowledge of the Gram-stain
reaction. This technique is essential in the identification and classification of
bacteria. In 1884, Hans Christian Gram found that bacteria could be divided into
two groups.
The study of the biology of bacteria requires some knowledge of the Gram-stain
reaction. This technique is essential in the identification and classification of
bacteria. In 1884, Hans Christian Gram found that bacteria could be divided into
two groups. In this process, purple dyes are poured over bacteria that have been
spread out thinly on a microscope slide and the cell walls of the bacteria (made
out of peptidoglycan) take up the colour. If a solvent is then applied to the slide,
bacteria which have only got a cell wall still keep their purple colour, but bacteria
which have got an extra cell membrane (made out of phospholipid) outside their
cell wall quickly lose the purple stain and become colourless; in order to be able
to see these bacteria under the microscope a second red stain is then used.
� Bacteria that manage to keep the original purple dye have only got a cell
wall - they are called Gram-positive.
� Bacteria that lose the original purple dye and can therefore take up the
second red dye have got both a cell wall and a cell membrane - they are
called Gram-negative.
Gram-positive Gram-negative
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Gram-positive bacteria have a cell wall composed of a single thick layer of
peptidoglycan. Gram-negative bacteria have a cell wall with several thinner layers
composed of peptidoglycan, lipopolysaccharide and protein. The Gram-stain
reaction can identify bacteria as Gram-positive or Gram-negative, but potentially
messy stains and expensive microscopes are needed. The KOH test is a faster and
simpler method to determine the same reaction. When Gram-negative bacterial
cells are placed in an alkaline solution (3% KOH), the cells walls are destroyed,
and the cell contents, including the DNA, are released. Because their cell wall
structure is different, Gram-positive bacteria will not lyse in 3% KOH. The KOH
method was originally developed by a Japanese scientist named Ryu in 1938.
The Gram-stain is an important diagnostic tool in human medicine because some
antibiotics are effective against only Gram-negative bacteria (e.g., erythromycin)
and some against only Gram-positive ones (e.g., penicillin, actinomycin). Bacteria
also cause plant diseases. Most plant pathogenic bacteria are Gram negative
(Agrobacterium, Erwinia, Pseudomonas, Ralstonia, and Xanthomonas). A few
bacterial genera found in association with plants are Gram-positive (Bacillus,
Clavibacter, and Streptomyces).5 For evaluation of antibacterial activity in our
case, we have used Staphylococcus aureus and Streptococcus pyogenes from
Gram-positive group of bacteria and Escherichia coli and Pseudomonas
aeruginosa from Gram-negative group of bacteria.
Classification and Mechanism of Action of Antimicrobial agents6
Antimicrobial agents are classified based on chemical structure and proposed
mechanism of action, as follows:
1. Agents that inhibit synthesis of bacterial cell walls, including the β-lactam
class (e.g., penicillins, cephalosporins and carbapenems) and dissimilar
agents such as cycloserine, vancomycin and bacitracin;
2. Agents that act directly on the cell membrane of the microorganism,
increasing permeability and leading to leakage of intracellular compounds,
including detergents such as polymyxin, polyene antifungal agents (e.g.,
nystatin and amphotericin B) which bind to cell-wall sterols and the
lipopeptide daptomycin;7
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3. Agents that disrupt function of 30S or 50S ribosomal subunits to reversibly
inhibit protein synthesis, which generally are bacteriostatic (e.g.,
chloramphenicol, tetracyclines, erythromycin, clindamycin, streptogramins and
linezolid);
4. Agents that bind to the 30S ribosomal subunit and alter protein synthesis,
which generally are bactericidal (e.g., aminoglycosides);
5. Agents that affect bacterial nucleic acid metabolism, such as the rifamycins
(e.g., rifampin and rifabutin), which inhibit RNA polymerase and the
quinolones which inhibit topoisomerases;
6. The antimetabolites, including trimethoprim and the sulfonamides which
block essential enzymes of folate metabolism.
There are several classes of antiviral agents, including:
1. Nucleic acid analogs such as acyclovir or ganciclovir which selectively inhibit
viral DNA polymerase, and zidovudine or lamivudine, which inhibit HIV
reverse transcriptase;
2. Non-nucleoside HIV reverse transcriptase inhibitors, such as nevirapine or
efavirenz;
3. Inhibitors of other essential viral enzymes, e.g., inhibitors of HIV protease or
influenza neuraminidase;
4. Fusion inhibitors such as enfuvirtide.
Additional categories likely will emerge as more complex mechanisms are
elucidated. The precise mechanism of action of some antimicrobial agents still is
unknown.
Antimicrobial activity of the synthesized compounds
It has been estimated that the life span of humans has increased by almost a
decade since the discovery of antimicrobial agents against microbial infections. A
consequence of our success with antibacterial agents and improved medical care
is the increase in the number of fungal infections. The incidence of fungal
infection has increased dramatically in the past 20 years partly due to increase
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in the number of people whose immune systems are compromised by AIDS,
aging, organ transplantation or cancer therapy. Accordingly, the increase in rates
of morbidity and mortality of infections has been now recognized as a major
problem. In response, pharmaceutical industry has developed a number of novel
less toxic antifungal for clinical use. Its increased use often for prolonged period,
has led to the increased incidence of infections with less common species, with
intrinsic resistance to one or more of the available antifungal agents.
Fungi are non-photosynthetic eukaryotes growing either as a colony of single
cells (yeasts) or as filamentous multicellular aggregates (molds). Most fungi live
as saprobes in soil or dead plant material and are important in the mineralization
of organic matter. Some are pathogens of humans and animals. The in vitro
methods used for detection of antifungal potency are similar to those used in
antibacterial screening. As with bacteria, it is easy to discover several synthetic
and natural compounds that, in minute quantities, can retard or prevent growth
of fungi.
Screening methods for antimicrobial activity
The following conditions must be follow for the screening of antimicrobial
activity:8-10 � There should be intimate contact between the test organisms and
substance to be evaluated.
� Required conditions should be provided for the growth of microorganisms.
� Conditions should be same through the study.
� Aseptic / sterile environment should be maintained.
Various methods have been used from time to time by several workers to evaluate
the antimicrobial activity. The evaluation can be done by the following methods.
� Turbidometric method
� Agar streak dilution method
� Serial dilution method
� Agar diffusion method
� Following Techniques are used as agar diffusion method
� Agar Cup method
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� Agar Ditch method
� Paper Disc method
We have used the Broth Dilution Method to screen the antimicrobial activity.
It is one of the non-automated in vitro microbial susceptibility tests. This classic
method yields a quantitative result for the amount of antimicrobial agents that is
needed to inhibit growth of specific microorganisms. It is carried out in tubes.
� Macrodillution Method in Tubes
� Microdillution format using plastic trays
In the present protocol we have used the Micro dilution format.
Materials and method
1. All the synthesized drugs were used for antimicrobial test procedures 2. All necessary controls like:
� Drug control;
� Vehicle control;
� Agar control;
� Organism control;
� Known antimicrobial drugs control;
� All MTCC cultures were tested against above mentioned known and
unknown drugs;
� Mueller hinton broth was used as nutrient medium to grow and dilute the
drug suspension for the test microorganism;
� Inoculum size for test strain was adjust to 106 CFU [Colony Forming Unit]
per milliliter by comparing the turbidity;
� Serial dilution technique was followed by micro method as per NCCLS-
1992 manual.11
Following common standard strains were used for screening of antibacterial and
antifungal activities. The strains were procured from Institute of Microbial
Technology, Chandigarh.
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� Escherichia coli (Gram-negative) MTCC-443
� Pseudomonas aeruginosa (Gram-negative) MTCC-1688
� Staphylococcus aureus (Gram-positive) MTCC-96
� Streptococcus pyogenes (Gram-positive) MTCC-442
� Candida albicans MTCC-227
� Aspergillus niger MTCC-282
� Aspergillus clavatus MTCC-1323
2% DMSO was used as diluent/vehicle to get desired concentration of drugs to
test upon standard bacterial strains.
Minimal inhibition concentration (MIC)
The main advantage of the ‘Broth Dilution Method’ for MIC determination lies
in the fact that it can readily be converted to determine the MIC as well.
1. Serial dilutions were prepared in primary and secondary screening.
2. The control tube containing no antibiotic is immediately sub cultured [before
inoculation] by spreading a loopful evenly over a quarter of [plate of medium
suitable for the growth of the test organism and put for incubation at 37 0C
overnight. The tubes are then incubated overnight.
3. The MIC of the control organism is read to check the accuracy of the drug
concentrations.
4. The lowest concentration inhibiting growth of the organism is recorded as
MIC.
5. The amount of growth from the control tube before incubation [which
represents the original inoculum] is compared.
Methods used for primary and secondary screening
Each synthesized drug was diluted obtaining 2000 μg/mL concentration, as a
stock solution.
Primary screen: In primary screening 1000 μg/mL, 500 μg/mL,
and 250 μg/mL concentrations of the synthesized drugs were
taken. The active synthesized drugs found in this primary screening
were further tested in a second set of dilution against all
microorganisms.
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Secondary screen: The drugs found active in primary screening
were similarly diluted to obtain 200 μg/mL, 100 μg/mL, 50 μg/mL,
25 μg/mL and 12.5 μg/mL concentrations.
Reading result
The highest dilution showing at least 99 % inhibition zone is taken as MIC. The
result of this is much affected by the size of the inoculum. The test mixture
should contain 106 organism/mL.
The standard drugs
The standard drugs used in the present study is “Ciprofloxacin” which showed
25, 25, 50 and 50 μg/mL and “Chloramphenicol” which displayed 50 μg/mL
MIC in six sets against E. coli, P. aeruginosa, S. aureus & S. pyogenes
respectively, for evaluating antibacterial activity. “Griseofulvin” is used as the
standard drug for antifungal activity which showed 500, 100 & 100 μg/mL MIC
in six sets against C. albicans, A. niger and A. clavatus respectively, used for the
antifungal activity.
Photographs of the strains used for antibacterial and antifungal activities
E. coli P. aeruginosa S. aureus
S. pyogenes C. albicans A. niger
A. clavatus
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Currently used antibacterial and antifungal drugs
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TABLE-1: ANTIMICROBIAL ACTIVITY OF 1-(2-(1H-BENZO[d]IMIDAZOL-2-YL)-2-METHYL-5-(ARYL)-1,3,4-OXADIAZOL-3(2H)-YL)-3-PHENYLPROP-2-EN-1-
ONES
Sr. No. -R
Minimum inhibitory concentration (MIC)
For bacteria (μg/mL) For fungi (μg/mL) E.c. P.a. S.a. S.p. C.a. A.n. A.c.
GK1-1 -H 500 1000 500 1000 500 1000 500 GK1-2 -2-Cl 100 100 200 125 100 100 50 GK1-3 -3-Cl 100 200 250 100 100 200 250 GK1-4 -4-Cl 25 12.5 50 25 50 100 12.5 GK1-5 -4-F 50 50 125 25 100 25 25 GK1-6 -2-CH3 500 500 250 500 1000 500 1000 GK1-7 -4-CH3 500 250 1000 500 500 250 250 GK1-8 -3-NO2 100 50 125 125 100 50 100 GK1-9 -4-NO2 25 50 25 12.5 50 25 12.5 GK1-10 -4-OH 500 200 100 250 250 1000 500 GK1-11 -3-OCH3 1000 500 500 500 500 500 1000 GK1-12 -4-OCH3 500 1000 500 250 250 500 1000 GK1-13 -4-Br 250 100 100 50 100 100 100 Ciprofloxacin 25 25 50 50 - - - Chloramphenicol 50 50 50 50 - - - Griseofulvin - - - - 500 100 100
TABLE-2: ANTIMICROBIAL ACTIVITY OF 1-(2-(1H-BENZO[d]IMIDAZOL-2-YL)-2-METHYL-5-(ARYL)-1,3,4-OXADIAZOL-3(2H)-YL)-3-(2-CHLOROPHENYL)
PROP-2-EN-1-ONES
Sr. No. -R
Minimum inhibitory concentration (MIC)
For bacteria (μg/mL) For fungi (μg/mL) E.c. P.a. S.a. S.p. C.a. A.n. A.c.
GK2-1 -H 1000 500 500 500 500 500 1000 GK2-2 -2-Cl 125 100 100 200 100 250 100 GK2-3 -3-Cl 200 100 200 100 200 100 250 GK2-4 -4-Cl 50 25 50 25 100 50 25 GK2-5 -4-F 25 50 50 12.5 25 50 25 GK2-6 -2-CH3 1000 500 500 200 1000 500 500 GK2-7 -4-CH3 500 500 1000 500 1000 500 500 GK2-8 -3-NO2 125 100 25 125 100 50 50 GK2-9 -4-NO2 50 50 12.5 25 100 250 25 GK2-10 -4-OH 500 250 200 500 250 500 250 GK2-11 -3-OCH3 1000 500 1000 500 500 1000 1000 GK2-12 -4-OCH3 1000 1000 500 500 250 1000 500 GK2-13 -4-Br 200 50 100 100 100 250 100 Ciprofloxacin 25 25 50 50 - - - Chloramphenicol 50 50 50 50 - - - Griseofulvin - - - - 500 100 100
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TABLE-3: ANTIMICROBIAL ACTIVITY OF 1-(2-(1H-BENZO[d]IMIDAZOL-2-YL)-2-METHYL-5-(ARYL)-1,3,4-OXADIAZOL-3(2H)-YL)-3-(3-CHLOROPHENYL)
PROP-2-EN-1-ONES
Sr. No. -R
Minimum inhibitory concentration (MIC)
For bacteria (μg/mL) For fungi (μg/mL) E.c. P.a. S.a. S.p. C.a. A.n. A.c.
GK3-1 -H 500 500 1000 1000 1000 500 1000 GK3-2 -2-Cl 100 100 125 100 50 100 100 GK3-3 -3-Cl 250 100 100 250 100 100 200 GK3-4 -4-Cl 50 50 50 25 50 12.5 25 GK3-5 -4-F 25 12.5 50 25 50 25 50 GK3-6 -2-CH3 500 500 250 500 500 250 500 GK3-7 -4-CH3 1000 500 500 200 500 1000 1000 GK3-8 -3-NO2 100 100 125 100 50 100 100 GK3-9 -4-NO2 50 25 12.5 25 25 25 50 GK3-10 -4-OH 1000 250 500 500 500 1000 250 GK3-11 -3-OCH3 500 500 1000 1000 1000 1000 1000 GK3-12 -4-OCH3 1000 500 500 1000 500 1000 1000 GK3-13 -4-Br 125 25 100 125 200 100 100 Ciprofloxacin 25 25 50 50 - - - Chloramphenicol 50 50 50 50 - - - Griseofulvin - - - - 500 100 100
TABLE-4: ANTIMICROBIAL ACTIVITY OF 1-(2-(1H-BENZO[d]IMIDAZOL-2-YL)-
2-METHYL-5-(ARYL)-1,3,4-OXADIAZOL-3(2H)-YL)-3-(4-CHLOROPHENYL) PROP-2-EN-1-ONES
Sr. No. -R
Minimum inhibitory concentration (MIC)
For bacteria (μg/mL) For fungi (μg/mL) E.c. P.a. S.a. S.p. C.a. A.n. A.c.
GK4-1 -H 1000 1000 500 500 500 1000 500 GK4-2 -2-Cl 125 100 100 50 100 50 100 GK4-3 -3-Cl 200 100 100 100 100 100 250 GK4-4 -4-Cl 125 50 25 50 25 100 50 GK4-5 -4-F 50 12.5 50 12.5 12.5 25 50 GK4-6 -2-CH3 1000 500 500 1000 1000 500 500 GK4-7 -4-CH3 500 1000 1000 250 1000 1000 1000 GK4-8 -3-NO2 200 100 125 100 100 100 100 GK4-9 -4-NO2 25 50 25 50 50 100 50 GK4-10 -4-OH 500 500 200 250 200 500 250 GK4-11 -3-OCH3 500 1000 1000 500 1000 500 1000 GK4-12 -4-OCH3 1000 1000 500 1000 1000 500 500 GK4-13 -4-Br 100 50 200 100 100 200 100 Ciprofloxacin 25 25 50 50 - - - Chloramphenicol 50 50 50 50 - - - Griseofulvin - - - - 500 100 100
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TABLE-5: ANTIMICROBIAL ACTIVITY OF 1-(2-(1H-BENZO[d]IMIDAZOL-2-YL)-2-METHYL-5-(ARYL)-1,3,4-OXADIAZOL-3(2H)-YL)-3-(4-HYDROXYPHENYL)
PROP-2-EN-1-ONES
Sr. No. -R
Minimum inhibitory concentration (MIC)
For bacteria (μg/mL) For fungi (μg/mL) E.c. P.a. S.a. S.p. C.a. A.n. A.c.
GK5-1 -H 500 500 1000 1000 1000 500 500 GK5-2 -2-Cl 100 100 125 100 200 100 100 GK5-3 -3-Cl 250 200 100 200 100 100 500 GK5-4 -4-Cl 25 50 50 25 50 25 50 GK5-5 -4-F 50 25 50 25 25 25 25 GK5-6 -2-CH3 1000 500 1000 500 500 1000 1000 GK5-7 -4-CH3 1000 500 1000 500 1000 1000 500 GK5-8 -3-NO2 100 100 100 125 100 100 100 GK5-9 -4-NO2 12.5 50 50 25 25 12.5 25 GK5-10 -4-OH 500 200 250 500 1000 500 500 GK5-11 -3-OCH3 1000 1000 500 1000 500 250 200 GK5-12 -4-OCH3 1000 1000 1000 1000 1000 500 1000 GK5-13 -4-Br 200 100 100 125 100 100 100 Ciprofloxacin 25 25 50 50 - - - Chloramphenicol 50 50 50 50 - - - Griseofulvin - - - - 500 100 100
TABLE-6: ANTIMICROBIAL ACTIVITY OF 1-(2-(3-(4-CHLOROPHENYL)-1-PHE-
NYL-1H-PYRAZOL-4-YL)-5-(PYRIDIN-4-YL)-1,3,4-OXADIAZOL-3(2H)-YL)-3-(ARYL)PROP-2-EN-1-ONES
Sr. No. -R
Minimum inhibitory concentration (MIC)
For bacteria (μg/mL) For fungi (μg/mL) E.c. P.a. S.a. S.p. C.a. A.n. A.c.
GK6-1 -H 1000 1000 500 1000 1000 500 1000 GK6-2 -2-Cl 500 1000 500 250 500 1000 1000 GK6-3 -3-Cl 1000 500 250 100 1000 500 500 GK6-4 -4-Cl 250 500 100 250 250 500 250 GK6-5 -4-F 500 500 200 250 500 200 250 GK6-6 -2-CH3 100 100 125 125 100 100 100 GK6-7 -4-CH3 50 25 25 25 50 50 25 GK6-8 -3-NO2 1000 500 250 500 1000 1000 1000 GK6-9 -4-NO2 500 500 250 250 1000 500 500 GK6-10 -4-OH 100 200 100 125 250 100 50 GK6-11 -3-OCH3 100 62.5 50 50 50 25 25 GK6-12 -4-OCH3 50 50 12.5 125 25 100 12.5 GK6-13 -4-Br 250 500 200 250 500 250 500 Ciprofloxacin 25 25 50 50 - - - Chloramphenicol 50 50 50 50 - - - Griseofulvin - - - - 500 100 100
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TABLE-7: ANTIMICROBIAL ACTIVITY OF 1-(2-(3-(4-FLUOROPHENYL)-1-PHE- NYL-1H-PYRAZOL-4-YL)-5-(PYRIDIN-4-YL)-1,3,4-OXADIAZOL-3(2H)-YL)-3-
(ARYL)PROP-2-EN-1-ONES
Sr. No. -R
Minimum inhibitory concentration (MIC)
For bacteria (μg/mL) For fungi (μg/mL) E.c. P.a. S.a. S.p. C.a. A.n. A.c.
GK7-1 -H 1000 500 500 1000 1000 1000 1000 GK7-2 -2-Cl 500 1000 500 500 1000 500 500 GK7-3 -3-Cl 1000 500 100 250 500 500 500 GK7-4 -4-Cl 250 500 100 250 250 500 250 GK7-5 -4-F 500 1000 250 200 1000 500 250 GK7-6 -2-CH3 100 125 100 200 100 50 250 GK7-7 -4-CH3 125 50 12.5 25 50 12.5 25 GK7-8 -3-NO2 500 500 250 500 1000 500 1000 GK7-9 -4-NO2 1000 500 200 250 1000 500 1000 GK7-10 -4-OH 200 100 125 62.5 100 100 500 GK7-11 -3-OCH3 50 125 50 125 100 25 100 GK7-12 -4-OCH3 25 50 25 50 25 50 25 GK7-13 -4-Br 500 250 200 200 1000 500 200 Ciprofloxacin 25 25 50 50 - - - Chloramphenicol 50 50 50 50 - - - Griseofulvin - - - - 500 100 100
TABLE-8: ANTIMICROBIAL ACTIVITY OF 1-(2-(3-(4-METHOXYPHENYL)-1-PH-
ENYL-1H-PYRAZOL-4-YL)-5-(PYRIDIN-4-YL)-1,3,4-OXADIAZOL-3(2H)-YL)-3-(ARYL)PROP-2-EN-1-ONES
Sr. No. -R
Minimum inhibitory concentration (MIC)
For bacteria (μg/mL) For fungi (μg/mL) E.c. P.a. S.a. S.p. C.a. A.n. A.c.
GK8-1 -H 500 1000 500 1000 1000 500 500 GK8-2 -2-Cl 500 1000 500 1000 1000 1000 500 GK8-3 -3-Cl 500 500 250 250 1000 1000 500 GK8-4 -4-Cl 100 500 250 250 500 500 250 GK8-5 -4-F 1000 1000 500 200 1000 500 500 GK8-6 -2-CH3 100 100 125 50 100 100 50 GK8-7 -4-CH3 50 12.5 25 12.5 12.5 12.5 12.5 GK8-8 -3-NO2 1000 500 500 250 1000 500 500 GK8-9 -4-NO2 500 500 250 500 1000 500 500 GK8-10 -4-OH 100 200 100 62.5 100 100 250 GK8-11 -3-OCH3 50 50 25 25 25 100 25 GK8-12 -4-OCH3 12.5 50 12.5 25 12.5 50 12.5 GK8-13 -4-Br 250 250 200 200 1000 500 500 Ciprofloxacin 25 25 50 50 - - - Chloramphenicol 50 50 50 50 - - - Griseofulvin - - - - 500 100 100
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TABLE-9: ANTIMICROBIAL ACTIVITY OF 1-(2-(3-(4-NITROPHENYL)-1-PHE- NYL-1H-PYRAZOL-4-YL)-5-(PYRIDIN-4-YL)-1,3,4-OXADIAZOL-3(2H)-YL)-3-
(ARYL)PROP-2-EN-1-ONES
Sr. No. -R
Minimum inhibitory concentration (MIC)
For bacteria (μg/mL) For fungi (μg/mL) E.c. P.a. S.a. S.p. C.a. A.n. A.c.
GK9-1 -H 1000 1000 500 500 500 500 1000 GK9-2 -2-Cl 1000 500 500 500 1000 1000 500 GK9-3 -3-Cl 500 200 250 500 500 1000 500 GK9-4 -4-Cl 200 500 250 250 1000 200 250 GK9-5 -4-F 500 1000 500 250 500 100 200 GK9-6 -2-CH3 125 100 125 50 50 100 100 GK9-7 -4-CH3 50 12.5 25 12.5 12.5 50 25 GK9-8 -3-NO2 500 1000 500 500 1000 500 200 GK9-9 -4-NO2 500 1000 500 500 500 500 1000 GK9-10 -4-OH 100 100 125 100 100 200 100 GK9-11 -3-OCH3 100 50 25 50 25 100 50 GK9-12 -4-OCH3 25 25 12.5 12.5 25 25 12.5 GK9-13 -4-Br 500 1000 500 500 500 200 250 Ciprofloxacin 25 25 50 50 - - - Chloramphenicol 50 50 50 50 - - - Griseofulvin - - - - 500 100 100
TABLE-10: ANTIMICROBIAL ACTIVITY OF 3-(6-(2,6-DICHLOROQUINOLIN-3-
YL)-4-(ARYL)-1,6-DIHYDROPYRIMIDIN-2-YLTHIO)PROPANENITRILES
Sr. No. -R
Minimum inhibitory concentration (MIC)
For bacteria (μg/mL) For fungi (μg/mL) E.c. P.a. S.a. S.p. C.a. A.n. A.c.
GK10-1 -H 1000 500 500 250 500 500 1000 GK10-2 -2-Cl 125 250 100 100 100 100 100 GK10-3 -3-Cl 100 200 250 100 500 200 250 GK10-4 -4-Cl 50 100 25 50 50 250 100 GK10-5 -4-F 50 100 25 12.5 12.5 50 25 GK10-6 -2-CH3 1000 500 200 500 1000 500 500 GK10-7 -4-CH3 500 500 1000 250 1000 500 1000 GK10-8 -3-NO2 125 12.5 100 25 100 12.5 100 GK10-9 -4-NO2 25 50 50 125 25 25 50 GK10-10 -3-OH 500 250 200 500 250 500 500 GK10-11 -4-OH 500 200 200 1000 200 500 250 GK10-12 -3-OCH3 500 500 1000 500 500 1000 500 GK10-13 -4-OCH3 500 250 500 1000 1000 1000 1000 GK10-14 -4-Br 100 250 100 250 100 250 100 Ciprofloxacin 25 25 50 50 - - - Chloramphenicol 50 50 50 50 - - - Griseofulvin - - - - 500 100 100
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TABLE-11: ANTIMICROBIAL ACTIVITY OF 3-(6-(2-CHLORO-6-FLUORO QUINOLIN-3-YL)-4-(ARYL)-1,6-DIHYDROPYRIMIDIN-2-YLTHIO)
PROPANENITRILES
Sr. No. -R
Minimum inhibitory concentration (MIC)
For bacteria (μg/mL) For fungi (μg/mL) E.c. P.a. S.a. S.p. C.a. A.n. A.c.
GK11-1 -H 500 500 250 500 1000 500 500 GK11-2 -2-Cl 125 25 100 125 100 200 250 GK11-3 -3-Cl 200 500 250 100 250 500 250 GK11-4 -4-Cl 25 100 25 50 100 100 50 GK11-5 -4-F 100 50 25 12.5 25 100 12.5 GK11-6 -2-CH3 500 500 250 250 1000 1000 500 GK11-7 -4-CH3 1000 500 1000 500 1000 1000 1000 GK11-8 -3-NO2 100 100 100 200 100 250 100 GK11-9 -4-NO2 25 12.5 50 25 12.5 25 50 GK11-10 -3-OH 500 250 250 250 250 500 1000 GK11-11 -4-OH 500 500 200 500 500 500 250 GK11-12 -3-OCH3 1000 250 500 1000 1000 500 500 GK11-13 -4-OCH3 500 500 1000 1000 1000 500 500 GK11-14 -4-Br 125 250 100 100 100 250 50 Ciprofloxacin 25 25 50 50 - - - Chloramphenicol 50 50 50 50 - - - Griseofulvin - - - - 500 100 100
TABLE-12: ANTIMICROBIAL ACTIVITY OF 3-(6-(2-CHLORO-6-METHOXY
QUINOLIN-3-YL)-4-(ARYL)-1,6-DIHYDROPYRIMIDIN-2-YLTHIO) PROPANENITRILES
Sr. No. -R
Minimum inhibitory concentration (MIC)
For bacteria (μg/mL) For fungi (μg/mL) E.c. P.a. S.a. S.p. C.a. A.n. A.c.
GK12-1 -H 250 500 1000 500 500 1000 500 GK12-2 -2-Cl 125 100 125 200 100 100 100 GK12-3 -3-Cl 100 250 250 100 250 250 250 GK12-4 -4-Cl 25 100 25 125 100 250 50 GK12-5 -4-F 12.5 25 50 25 12.5 50 25 GK12-6 -2-CH3 1000 500 250 500 1000 500 500 GK12-7 -4-CH3 500 500 500 1000 1000 500 500 GK12-8 -3-NO2 50 100 125 100 100 25 50 GK12-9 -4-NO2 12.5 12.5 50 50 25 25 12.5 GK12-10 -3-OH 1000 500 500 500 500 500 500 GK12-11 -4-OH 1000 500 500 250 1000 250 250 GK12-12 -3-OCH3 1000 500 500 1000 1000 500 1000 GK12-13 -4-OCH3 500 500 500 500 500 250 500 GK12-14 -4-Br 100 250 100 200 100 250 250 Ciprofloxacin 25 25 50 50 - - - Chloramphenicol 50 50 50 50 - - - Griseofulvin - - - - 500 100 100
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References
1. Patrick GL; ‘An Introduction to Medicinal Chemistry’, Oxford University
Press, New York, 1995.
2. Barrows W; ’Text Book of Microbiology’, W B Saunders Co., Philadelphia,
17th ed, 1959.
3. http://www.microbiologybytes.com/iandi/3a.html
4. Woese CR, Kandler O, Wheelis ML; ‘Towards a natural system of
organisms: proposal for the domains Archaea, Bacteria, and Eucarya’; Proc
Natl Acad Sci U.S.A., 87, 4576, 1990.
5. http://www.apsnet.org/education/K-12PlantPathways/TeachersGuide/
Activities/DNA_Easy/exercisepg1.htm
6. Brunton LL, Lazo JS, Parker KL; ‘Goodman & Gilman's the Pharmacological
basis of Therapeutics’, Mcgraw-Hill Medical Publishing Division, 2006.
7. Carpenter CF, Chambers HF; Clin Infect Dis, 38, 994, 2004.
8. Robert C; “Medical Microbiology”, ELBS and E & S; Livingstone, Briton,
11th ed., 895, 1970.
9. Sujatha GD; Ind J Expt Biol, 13, 286, 1975.
10. Walksman SA; “Microbial Antagonism and Antibiotic Substances”, Common
Wealth Fund, New York, 2nd ed, 72, 1947.
11. National Committee for Clinical Laboratory Standard., Reference method
for broth dilution antifungal susceptibility testing of yeasts Approved
standard M27A. NCCLS, Wayne, PA, 1997.