|
International Journal of ChemTech Research CODEN (USA): IJCRGG, ISSN: 0974-4290, ISSN(Online):2455-9555 Vol.10 No.1 pp 139-147, 2017
|
Synthesis, Characterization and Antimicrobial Screening of Some Novel N-Substituted-2-Pyrazolines, Derived from Chalcones
Satish Babulal Jadhav*, Achyut S. Munde, Mohd. Shafique,
Shantilal D. Rathod
P. G. Department of Chemistry, Milind College of Science, Aurangabad-431002, Maharashtra, India
Abstract : A new series of(3-(2,4-dichlorophenyl)-5-methylisoxazol-4-yl)(3-(4-substituted phenyl)-5-(6-methoxynaphthalen-1-yl)-4,5-dihydro-1H-pyrazol-1-yl)methanone(6a-g) and (3-(4-fluorophenyl)-5-(6-methoxy naphthalen-1-yl)-4,5-dihydro-1H-pyrazol-1-yl)(pyridin-4-yl)methanone (7a-g)were synthesized by reacting 3-(6-methoxynaphthalen-1-yl)-1-(4-methoxyphenyl)prop-2-en-1-one (Chalcone)(3a-g) with hydrazine hydrate followed by 3-(2,4-dichlorophenyl)-5-methylisoxazole-4-carbonyl chloride (5) and isonicotinohydrazide respectively. Allthese compounds were characterized by means of their IR, 1H NMR, mass and elemental analysis. All the synthesized products were evaluated for their antimicrobial activity. All the compounds exhibited significant to moderate antimicrobial activity.
Keywords : Chalcone, N-substituted-2-Pyrazoline, isonicotinohydrazide, Antibacterial, Antifungal activity.
Introduction
Medicinal chemistry is the science that deals with the discovery and design of new therapeutic chemicals. Many of these chemicals are used as medicine in treatment of infectious diseases. The high therapeutic properties of the related drugs have encouraged the medicinal chemists to synthesize a large number of novel chemotherapeutic agents1. Much attention has paid to synthesis of nitrogen containing heterocyclic compounds. Nitrogen and oxygen containing heterocycles are of special interest because they constitute an important class of natural and non-natural products, many of which exhibit broad spectrum of biological and pharmacological activities.
Much attention has paid to the synthesis of nitrogen and oxygen containing heterocyclic compounds like Pyrazoles and isoxazoles2 mainly due to their broad spectrum of biological and pharmacological activities3,4. Pyrazoles signifies a key motif in heterocyclic chemistry and occupies a major position in medicinal and pesticide chemistry due to its wide range of bioactivities such as antibacterial5, anticancer6, analgesic and anti-inflammatory7. Whereas, isoxazoles possess a broad spectrum of pharmacological activities such as antibacterial8, antiviral9, antidepressant10and anti-TB activity11activity. As per literature review the pyridine, naphthalene derivatives also possess analgesic12 and anti-inflammatory13activities. The synthesis of heterocyclic motifs containing multi-structure in one molecule has received much interest in recent years14.
Literature survey revealed that when one biodynamic heterocyclic system was coupled with another, a molecule with enhanced biological activity15was produced. The chemistry of these linked biheterocycles have
been the fascinating field of investigation in medicinal chemistry as they have been found to exhibit enhanced biological profile16. In view of the biological and medicinal activity of pyrazoline, isoxazoles and pyridyl/napthyl ring, it was thought worth-while to synthesize and investigates the activity of the compounds in which pyrazoline moiety has been linked with isoxazoles, similarly pyrazoline linked with pyridyl/napthyl ring.
Material and Methods
Experimental
Melting points were determined in open capillaries and are uncorrected.IR spectra were recorded using Perkin –Elmer spectrometer.1H NMR spectra were recorded on Brucker Advance II 400 spectrometer in DMSO by using TMS as internal standard. Thin layer chromatography was performed with E.Merkprecoated TLC plates, silica gel 60F254 with thickness of 0.25mm and spots were visualized by irradiation with ultraviolet light (254 nm).
General procedure for the synthesis of 3-(6-methoxynaphthalen-1-yl)-1-(4-substituted phenyl)prop-2-en-1-one(Chalcone)17 (3a-g).
A mixture of 4-substituted acetophenone(1a-g)(0.01mole) and 6-methoxy-1-naphthaldehyde (2)(0.01mole) was stirred in methanol (50 mL) and then a solution of 15 mL potassium hydroxide (0.02mole) was added to it. The mixture was kept overnight at room temperature and then it was poured into crushed ice and acidified with dil. hydrochloric acid. The chalcones i.e. [3-(6-methoxynaphthalen-1-yl)-1-(4-substituted phenyl)prop-2-en-1-one] (3a-g)precipitate out as solid (Scheme‐I). The obtained solid was filtered, washed with water, dried and purified by recrystallization from acetic acid.
General procedure for the synthesis of 5-(6-methoxynaphthalen-1-yl)-3-(4-substituted phenyl)-4,5-dihydro-1H-pyrazole18 (4a-g).
A mixture ofChalcone (0.01mole) i.e. [3-(6-methoxynaphthalen-1-yl)-1-(4-substituted phenyl)prop-2-en-1-one](3a-g)was dissolved in 50 ml of methanol. To this reaction mixture, (0.02mole) of hydrazine hydrate was added. The reaction mass was heated under reflux for 3-4 hr. TLC checked, after completion of reaction, a reaction mixture was cooled to room temperature and kept overnight. Poured on ice cold water the obtained solid was filtered and wash with cold water for several times(Scheme‐I). The final compound was crystallized from ethanol.
General procedure for the synthesis of(3-(2,4-dichlorophenyl)-5-methylisoxazol-4-yl)(3-(4-substitutedphenyl)-5-(6-methoxynaphthalen-1-yl)-4,5-dihydro-1H-pyrazol-1-yl)methanone (6a-g).
5-(6-methoxynaphthalen-1-yl)-3-(4-substitutedphenyl)-4,5-dihydro-1H-pyrazole (0.01mole) (4a-g) was dissolved in pyridine (0.03mole) to this 3-(2,4-dichlorophenyl)-5-methylisoxazole-4-carbonyl chloride (0.01mole) (5) was added with constant stirring. The reaction mixture was refluxed for 1 hr. and then it was poured on crushed ice and acidified with dilute hydrochloric acid, a white color precipitate of (3-(2,4-dichlorophenyl)-5-methylisoxazol-4-yl)(5-(6-methoxynaphthalen-1-yl)-3-(4-substitutedphenyl)-4,5-dihydro-1H-pyrazol-1-yl)methanone(6a-g) separated out. The so formed precipitate was filtered, dried and purified by crystallization from ethanol.Their percentage yield and physical constants were recorded in Table I.
General procedure for the synthesis of` (3-(4-substituted phenyl)-5-(6-methoxy
naphthalen-1-yl)-4,5-dihydro-1H-pyrazol-1-yl)(pyridin-4-yl)methanone (7a-g)
A mixture of 1-(4-substituted phenyl)-3-(6-methoxynaphthalen-1-yl)prop-2-en-1-one (3a-g)(0.01mole) and isonicotinohydrazide (0.02mole) in 50 mL ethanolwas reflux for 6-8 hrs., excess ethanol was distilled and the resulting solution was keptovernight at room temperature and then it was poured on crushed ice,the precipitate of (3-(4-substituted phenyl)-5-(6-methoxynaphthalen-1-yl)-4,5-dihydro-1H-pyrazol-1-yl)(pyridin-4-yl)methanone(4a-g) separated out. Then it was filtered, dried and purified by crystallization from acetic acid. Their percentage yield and physical constants were recorded in Table II.
Table I. Analytical Data and Elemental Analysis of Compounds 6(a-g)
Compd. |
Molecular formula |
M.P. 0C |
Yield % |
Elemental Analysis |
|||||
%C |
% H |
%N |
|||||||
Calcd. |
Found |
Calcd. |
Found |
Calcd. |
Found |
||||
6a |
C31H23Cl2N3O3 |
120 |
85 |
66.91 |
66.85 |
4.17 |
4.10 |
7.55 |
7.52 |
6b |
C31H22Cl3N3O3 |
112 |
90 |
63.01 |
62.85 |
3.75 |
3.70 |
7.11 |
7.00 |
6c |
C31H22BrCl2N3O3 |
140 |
87 |
58.60 |
58.55 |
3.49 |
3.40 |
6.61 |
6.55 |
6d |
C31H22Cl2FN3O3 |
88 |
92 |
64.82 |
64.80 |
3.86 |
3.80 |
7.32 |
7.30 |
6e |
C32H25Cl2N3O3 |
125 |
90 |
67.37 |
67.30 |
4.42 |
4.38 |
7.37 |
7.35 |
6f |
C32H25Cl2N3O4 |
148 |
80 |
65.54 |
65.46 |
4.30 |
4.26 |
7.16 |
7.12 |
6g |
C31H21Cl4N3O3 |
130 |
75 |
59.54 |
59.50 |
3.38 |
3.32 |
6.72 |
6.70 |
Table II. Analytical Data and Elemental Analysis of Compounds 7(a-g)
Compd. |
Molecular formula |
M.P. 0C |
Yield % |
Elemental Analysis |
|||||
%C |
% H |
%N |
|||||||
Calcd. |
Found |
Calcd. |
Found |
Calcd. |
Found |
||||
7a |
C26H21N3O2 |
188 |
82 |
76.64 |
76.54 |
5.19 |
5.15 |
10.31 |
10.25 |
7b |
C26H20ClN3O2 |
180 |
85 |
70.67 |
70.64 |
4.56 |
4.51 |
9.51 |
9.45 |
7c |
C26H20BrN3O2 |
184 |
78 |
64.21 |
64.14 |
4.14 |
4.10 |
8.64 |
8.58 |
7d |
C26H20FN3O2 |
190 |
80 |
73.40 |
73.30 |
4.74 |
4.72 |
9.88 |
9.85 |
7e |
C27H23N3O2 |
172 |
85 |
76.94 |
76.90 |
5.50 |
5.47 |
9.97 |
9.95 |
7f |
C27H23N3O3 |
158 |
75 |
76.94 |
76.90 |
5.50 |
5.47 |
9.97 |
9.95 |
7g |
C26H19Cl2N3O2 |
175 |
70 |
65.56 |
65.50 |
4.02 |
3.97 |
8.82 |
8.75 |
Antimicrobial activity
All the newly synthesized compounds 6a-g and 7a-g was tested for their antimicrobial activity. The effects of unknown compounds were compared with the standard drug Penicillin for bacteria and Greseofulvin for fungi. Antibacterial activity was performed against staphylococcus aureus, Escherichia coli, Salmonella Typhi and antifungal activity against Aspergillusniger, Aspergillusflavus and Penicilliumchrysogenum. The antibacterial activity was assayed by cup plate method19 and antifungal activity was assayed by standard agar disc diffusion method20.The results are shown in Table III and IV respectively.
Table III-Antibacterial screening results of the compounds 6a-g & 7a-g.
Sr. No. |
Compounds |
E.coli |
Salmonella typhi |
Staphylococcus aureus |
Bacillus subtilis |
Diameter of growth inhibition zone (mm) |
|||||
1 |
6a |
10 |
13 |
14 |
16 |
2 |
6b |
17 |
19 |
26 |
28 |
3 |
6c |
14 |
14 |
20 |
19 |
4 |
6d |
17 |
15 |
18 |
20 |
5 |
6e |
13 |
12 |
10 |
17 |
6 |
6f |
14 |
17 |
22 |
24 |
7 |
6g |
12 |
13 |
15 |
17 |
8 |
7a |
12 |
10 |
15 |
18 |
9 |
7b |
16 |
17 |
22 |
24 |
10 |
7c |
16 |
18 |
20 |
22 |
11 |
7d |
18 |
18 |
18 |
21 |
12 |
7e |
13 |
14 |
21 |
13 |
13 |
7f |
17 |
16 |
22 |
24 |
14 |
7g |
13 |
16 |
18 |
16 |
15 |
Penicillium |
22 |
25 |
35 |
38 |
16 |
DMSO |
-ve |
-ve |
-ve |
-ve |
|
-ve no antibacterial activity |
Table IV- Antifungal screening results of the compounds 6a-g & 7a-g.
Sr. No. |
Compounds |
Aspergillus niger |
Aspergillusflavus |
Penicillumchrysogenum |
Fusariummoneliforme |
1 |
6a |
-ve |
-ve |
+ve |
-ve |
2 |
6b |
-ve |
-ve |
-ve |
-ve |
3 |
6c |
+ve |
-ve |
-ve |
-ve |
4 |
6d |
-ve |
+ve |
-ve |
-ve |
5 |
6e |
+ve |
RG |
+ve |
-ve |
6 |
6f |
-ve |
-ve |
-ve |
-ve |
7 |
6g |
-ve |
-ve |
-ve |
-ve |
8 |
7a |
+ve |
-ve |
RG |
+ve |
9 |
7b |
-ve |
-ve |
-ve |
-ve |
10 |
7c |
-ve |
-ve |
RG |
-ve |
11 |
7d |
-ve |
-ve |
+ve |
-ve |
12 |
7e |
+ve |
RG |
+ve |
-ve |
13 |
7f |
-ve |
-ve |
-ve |
-ve |
14 |
7g |
-ve |
-ve |
-ve |
-ve |
15 |
Griseofulvin |
-ve |
-ve |
-ve |
-ve |
16 |
DMSO |
+ve |
+ve |
+ve |
+ve |
-ve No growth Antifungal activity present +ve Growth Antifungal activity absent RG Reduced growth |
Results and Discussion
(3-(2,4-dichlorophenyl)-5-methylisoxazol-4-yl)(3-(4-substitutedphenyl)-5-(6-methoxy naphthalen-1-yl)-4,5-dihydro-1H-pyrazol-1-yl)methanone(6a-g)& (3-(4-substituted phenyl) -5-(6-methoxynaphthalen-1-yl)-4,5-dihydro-1H-pyrazol-1-yl)(pyridin-4-yl) methanone(7a-g) were successfully synthesized as per the scheme-I.The entire synthesized compounds are qualitatively analyzed by running T.L.C. and melting point. Thestructures of the compounds synthesized are confirmed by IR,1HNMR and mass spectral data.
Analytical and spectral data (IR, 1H-NMR) of all synthesized compounds were in full agreement with proposed structure. The IR spectrum of 6a-g exhibited a band due to1693 Cm-1 (C=N, pyrazoline ring), 1642 Cm-1 (C=O), 1600 Cm-1 (C=C), 1162 Cm-1 (-OCH3), but the absence of absorption peak at 3450 Cm-1 due to (N-H), which is present in 4a-g. Further, in their 1H NMR (DMSO) spectrum, the appearance of a signal at 5.80-5.78 (dd, 1H, J=8.2 Hz, Hx), 4.24-4.19 (dd, 1H, J=9.45 Hz, HB), 3.93 (s, 3H, -OCH3), 3.16-3.10 (dd, 1H, J=9.3 Hz, HA), 2.73 (s, 3H, -CH3). Similarly, the structures of compounds 7a-gwere confirmed on the basis of spectral and elemental analysis. The IR spectrum of 7a-gexhibited a band due3050Cm-1 (Aromatic C-H streaching), 1652 Cm-1 (C=O), 1608 Cm-1 (C=N, pyrazoline ring), 1508 (C=C), 1154 (-OCH3). Further, in their 1H NMR (DMSO) spectrum, the appearance of a signal at5.65-5.61 (dd, 1H, Hxpyrazoline), 3.77-3.53 (dd, 1H, HBpyrazoline), 3.35 (s, 3H, -OCH3) 3.12-3.08 (dd, 1H, HApyrazoline).
The compounds 6a-gand 7a-gwere screened for their antibacterial and antifungal activity. The investigation of antibacterial screening results indicate that compounds 6b,d, 7d,f shows high activity against E.coli,similarly compounds6b,f, 7c,d also shows good activity against Salmonella typhi, compounds 6b,c,f, 7b,c,f shows better activity against Staphylococcus aureus and compounds 6b,d,f, 7b,c,f shows best activity against Bacillus subtilis. The investigation of antifungal activity data revealed that compounds 6a,b,d,f,g, 7b,c,d,f,g show inhibitory effect against Aspergillusniger and compounds 6a,b,c,f,g,7a,b,c,f,g show inhibitory effect against Aspergillusflavus. Compounds 6b,c,d,f,g, 7b,f,g show inhibitory effect against Penicillumchrysogenum. similarly most of the compounds are active against Fusariummoneliforme.Remaining compounds are inactive against all the fungus.
Spectral data of synthesized compounds (6a-g) &(7a-g)
Compound (6a): (3-(2,4-dichlorophenyl)-5-methylisoxazol-4-yl)(4,5-dihydro-5-(6-
Methoxynaphthalen-1-yl)-3-phenylpyrazol-1-yl)methanone
IR (KBr pellets Cm‐1): 1693 (C=N, pyrazoline ring), 1642 (>C=O), 1600 (C=C), 1162(-OCH3); 1H NMR (DMSO, 400 MHz) δ 8.65-7.20 (m, 14H, Ar-H), 5.80-5.78 (dd, 1H, J=8.2 Hz, Hx), 4.24-4.19 (dd, 1H, J=9.45 Hz, HB), 3.93 (s, 3H, -OCH3), 3.16-3.10 (dd, 1H, J=9.3 Hz, HA), 2.73 (s, 3H, -CH3); Mass (m/z): 556.12, 557.19(M+1).
Compound (6b):(3-(4-chlorophenyl)-4,5-dihydro-5-(6-methoxynaphthalen-1-yl)pyrazol-
1-yl)(3-(2,4-dichlorophenyl)-5-methylisoxazol-4-yl)methanone
IR (KBr pellets Cm‐1): 1692 (C=N, pyrazoline ring), 1640 (>C=O),1600 (C=C), 1160 (-OCH3); 1H NMR (DMSO, 400 MHz) δ 8.60-7.18 (m, 13H, Ar-H), 5.80-5.78 (dd, 1H, J=8.0 Hz, Hx), 4.22-4.18 (dd, 1H, J=9.43 Hz, HB), 3.92 (s, 3H, -OCH3), 3.15-3.11 (dd, 1H, J=9.3 Hz, HA), 2.70 (s, 3H, -CH3); Mass (m/z): 590.12 (M+1).
Compound (6c):(3-(4-bromophenyl)-4,5-dihydro-5-(6-methoxynaphthalen-1-yl)pyrazol-
1-yl)(3-(2,4-dichlorophenyl)-5-methylisoxazol-4-yl)methanone
IR (KBr pellets Cm‐1): 1695 (C=N, pyrazoline ring),1638 (>C=O), 1620 (C=C), 1168 (-OCH3); 1H NMR (DMSO, 400 MHz) δ 8.62-7.18 (m, 13H, Ar-H), 5.78-5.75 (dd, 1H, J=8.3 Hz, Hx), 4.21-4.17 (dd, 1H, J=9.48 Hz, HB), 3.90 (s, 3H, -OCH3), 3.15-3.11 (dd, 1H, J=9.3 Hz, HA), 2.75 (s, 3H, -CH3); Mass (m/z): 635.12, 637.16 (M+1).
Compound (6d):(3-(2,4-dichlorophenyl)-5-methylisoxazol-4-yl)(3-(4-fluorophenyl)-4,5-
dihydro-5-(6-methoxynaphthalen-1-yl)pyrazol-1-yl)methanone
IR (KBr pellets Cm‐1): 1695 (C=N, pyrazoline ring), 1642 (>C=O),1623 (C=C), 1170 (-OCH3); 1H NMR (DMSO, 400 MHz) δ 8.60-7.16 (m, 13H, Ar-H), 5.77-5.76 (dd, 1H, J=8.2 Hz, Hx), 4.20-4.17 (dd, 1H, J=9.5 Hz, HB), 3.95 (s, 3H, -OCH3), 3.16-3.12 (dd, 1H, J=9.2 Hz, HA), 2.70 (s, 3H, -CH3); Mass (m/z): 575.10 (M+1).
Compound (6e):(3-(2,4-dichlorophenyl)-5-methylisoxazol-4-yl)(4,5-dihydro-5-(6-
methoxynaphthalen-1-yl)-3--(4-methylphenyl)pyrazol-1-yl)methanone
IR (KBr pellets Cm‐1): 1695 (C=N, pyrazoline ring), 1645 (>C=O), 1623 (C=C), 1170 (-OCH3); 1H NMR (DMSO, 400 MHz) δ 8.63-7.15 (m, 13H, Ar-H), 5.75-5.72 (dd, 1H, J=8.3 Hz, Hx), 4.20-4.17 (dd, 1H, J=9.5 Hz, HB), 3.90 (s, 3H, -OCH3), 3.15-3.13 (dd, 1H, J=9.3 Hz, HA), 2.70 (s, 3H, -CH3), 2.65 (s, 3H, -CH3); Mass (m/z): 570.13 (M+1).
Compound (6f): (3-(2,4-dichlorophenyl)-5-methylisoxazol-4-yl)(4,5-dihydro-5-(6-
methoxynaphthalen-1-yl)-3-(4-methoxyphenyl)pyrazol-1-yl)methanone
IR (KBr pellets Cm‐1): 1690 (C=N, pyrazoline ring), 1635 (>C=O),1610 (C=C), 1165 (-OCH3); 1H NMR (DMSO, 400 MHz) δ 8.55-7.10 (m, 13H, Ar-H), 5.82-5.80 (dd, 1H, J=8.2 Hz, Hx), 4.25-4.19 (dd, 1H, J=9.45 Hz, HB), 3.90 (s, 6H, 2 X -OCH3), 3.15-3.10 (dd, 1H, J=9.3 Hz, HA), 2.70 (s, 3H, -CH3); Mass (m/z): 587.12 (M+1).
Compound (6g):(3-(2,4-dichlorophenyl)-5-(6-methoxynaphthalen-1-yl)-4,5-dihydro-1H-
pyrazol-1-yl)(3-(2,4-dichlorophenyl)-5-methylisoxazol-4-yl)methanone
IR (KBr pellets Cm‐1): 1695 (C=N, pyrazoline ring),1642 (>C=O), 1623 (C=C), 1170 (-OCH3); 1H NMR (DMSO, 400 MHz) δ 8.57-7.15 (m, 12H, Ar-H), 5.80-5.84 (dd, 1H, J=8.2 Hz, Hx), 4.26-4.20 (dd, 1H, J=9.40
Hz, HB), 3.92 (s, 3H, -OCH3), 3.15-3.10 (dd, 1H, J=9.3 Hz, HA), 2.73 (s, 3H, -CH3); Mass (m/z): 625.12, 627.22 (M+1).
Compound (7a):(5-(6-methoxynaphthalen-1-yl)-3-phenyl-4,5-dihydro-1H-pyrazol-1-yl)
(pyridin-4-yl)methanone
IR (KBr pellets Cm‐1): 3050 (Aromatic C-H streaching), 1652 (>C=O), 1608 (C=N, pyrazoline ring), 1508 (C=C), 1154 (-OCH3); 1H NMR (DMSO, 400 MHz) 8.75-6.45 (m, 15H, Ar-H), 5.65-5.61 (dd, 1H, Hxpyrazoline), 3.77-3.53 (dd, 1H, HB pyrazoline), 3.35 (s, 3H, -OCH3) 3.12-3.08 (dd, 1H, HApyrazoline); Mass (m/z): 408.17 (M+1).
Compound (7b):(3-(4-chlorophenyl)-5-(6-methoxynaphthalen-1-yl)-4,5-dihydro-1H-
pyrazol-1-yl)(pyridin-4-yl)methanone
IR (KBr pellets Cm‐1): 3020 (Aromatic C-H streaching), 1650 (>C=O), 1615 (C=N, pyrazoline ring), 1520 (C=C), 1160 (-OCH3); 1H NMR (DMSO, 400 MHz) 8.79-6.50 (m, 14H, Ar-H), 5.64-5.60 (dd, 1H, Hxpyrazoline), 3.77-3.53 (dd, 1H, HB pyrazoline), 3.33 (s, 3H, -OCH3) 3.14-3.09 (dd, 1H, HApyrazoline); Mass (m/z): 423.12 (M+1).
Compound (7c):(3-(4-bromophenyl)-5-(6-methoxynaphthalen-1-yl)-4,5-dihydro-1H-
pyrazol-1-yl)(pyridin-4-yl)methanone
IR (KBr pellets Cm‐1): 3022 (Aromatic C-H streaching), 1645 (>C=O), 1620 (C=N, pyrazoline ring), 1520 (C=C), 1162 (-OCH3); 1H NMR (DMSO, 400 MHz) 8.78-6.50 (m, 14H, Ar-H), 5.64-5.60 (dd, 1H, Hxpyrazoline), 3.75-3.50 (dd, 1H, HB pyrazoline), 3.35 (s, 3H, -OCH3) 3.15-3.09 (dd, 1H, HApyrazoline); Mass (m/z): 486.08, 488.13 (M+1).
Compound (7d):(3-(4-fluorophenyl)-5-(6-methoxynaphthalen-1-yl)-4,5-dihydro-1H-
pyrazol-1-yl)(pyridin-4-yl)methanone
IR (KBr pellets Cm‐1): 3056 (Aromatic C-H streaching),1655 (>C=O), 1606 (C=N, pyrazoline ring), 1508 (C=C), 1157 (-OCH3); 1H NMR (DMSO, 400 MHz) 8.14-6.32 (m, 14H, Ar-H), 5.69-5.66 (dd, 1H, Hxpyrazoline), 3.68-3.55 (dd, 1H, HB pyrazoline), 3.82 (s, 3H, -OCH3) 3.15-3.10 (dd, 1H, HApyrazoline); Mass (m/z): 426.16 (M+1).
Compound (7e):(5-(6-methoxynaphthalen-1-yl)-3-(p-tolyl)-4,5-dihydro-1H-pyrazol-1-
yl)(pyridin-4-yl)methanone
IR (KBr pellets Cm‐1): 3036 (Aromatic C-H streaching), 1652 (>C=O), 1610 (C=N, pyrazoline ring), 1508 (C=C), 1160 (-OCH3); 1H NMR (DMSO, 400 MHz) 8.20-6.30 (m, 14H, Ar-H), 5.60-5.66 (dd, 1H, Hxpyrazoline), 3.68-3.55 (dd, 1H, HB pyrazoline), 3.75 (s, 3H, -OCH3) 3.15-3.10 (dd, 1H, HApyrazoline), 2.73 (s, 3H, -CH3); Mass (m/z): 422.16 (M+1).
Compound (7f):(5-(6-methoxynaphthalen-1-yl)-3-(4-methoxyphenyl)-4,5-dihydro-1H-
pyrazol-1-yl)(pyridin-4-yl)methanone
IR (KBr pellets Cm‐1): 3040 (Aromatic C-H streaching), 1651 (>C=O), 1610 (C=N, pyrazoline ring), 1525 (C=C), 1155 (-OCH3); 1H NMR (DMSO, 400 MHz) 8.20-6.30 (m, 14H, Ar-H), 5.62-5.68 (dd, 1H, Hxpyrazoline), 3.68-3.53 (dd, 1H, HB pyrazoline), 3.83 (s, 6H, 2 x -OCH3) 3.16-3.12 (dd, 1H, HApyrazoline); Mass (m/z): 438.22 (M+1).
Compound (7g):(3-(2,4-dichlorophenyl)-5-(6-methoxynaphthalen-1-yl)-4,5-dihydro-1H-
pyrazol-1-yl)(pyridin-4-yl)methanone
IR (KBr pellets Cm‐1): 3040 (Aromatic C-H streaching), 1657 (>C=O), 1615 (C=N, pyrazoline ring), 1520 (C=C), 1156 (-OCH3); 1H NMR (DMSO, 400 MHz) 8.25-6.28 (m, 13H, Ar-H), 5.60-5.68 (dd, 1H, Hxpyrazoline), 3.68-3.53 (dd, 1H, HB pyrazoline), 3.73 (s, 3H, -OCH3) 3.15-3.11 (dd, 1H, HApyrazoline); Mass (m/z): 477.12 (M+1).
Conclusion
In conclusion, we have reported some novel N-substituted-2-pyrazolines, in which pyrazoline moiety is linked with isoxazoles, similarly pyrazoline linked with pyridyl/napthyl ring, which possess good to moderate antimicrobial activity. In this study the pharmacophore whichpossess pyrazoline moiety which is coupled withisoxazoles ring, pyridyl ring and groups substituted like bromo, chloro, flouro, and methoxy may provide us the fruitful results in biological and medicinal purposes.
Acknowledgments
The author gratefully acknowledges SAIF and CIL Chandigarh, for IR, NMR spectra .The author thanks to Principal Milind College of Science, Aurangabad for providing research facility. The author also thanks to Head Department of Biotechnology Milind College of Science, Aurangabad for microbial activity.
References
*****