Synthesis and evaluation of some novel N-(3,5-diphenyl-4,5-dihydro-1,2-oxazol-4-yl)methyl,aniline)-n-(4-sulfamoylphenyl) benzamide and N-(3,5-diphenyl-4,5-dihydro-1,2-oxazol-4-yl)methyl aniline)benzene sulfonamide for anti-tubercular activity
Dighe P. R.*, Mahajan V. R., Maste M. M., Bhat A. R.
Department of Pharmaceutical Chemistry, S.M.B.T. College of Pharmacy, Nandi Hills, Dhamangaon , Tal. Igatpuri, Dist. Nashik
*Corresponding Author E-mail: pravin_dighe85@rediffmail.com
ABSTRACT:
A series of N-(3,5-diphenyl-4,5-dihydro-1,2-oxazol-4-yl)methyl aniline)-n-(4-sulfamoylphenyl)benzamide and N-(3,5-diphenyl-4,5-dihydro-1,2-oxazol-4-yl)methyl aniline)benzene sulfonamide have been synthesized. Various aromatic ketone reacts with aromatic aldehyde using NaOH as a catalyst gives 1,3-diphenylprop-2-en-1-one, which on further refluxed with hydroxylamine hydrochloride using potassium hydroxide as a catalyst afforded isoxazoline. Thus obtained isoxazoline on further condensed with formaldehyde and benzocaine to give N-(3,5-diphenyl-4,5-dihydro-1,2-oxazol-4-yl)methyl aniline)-4-ethyl benzoate, which on further condensed with sulphanilamide to give N-(3,5-diphenyl-4,5-dihydro-1,2-oxazol-4-yl)methyl aniline)-n-(4-sulfamoylphenyl)benzamide (A1-5) .Isoxazoline also condensed with formaldehyde and sulphanilamide to give N-(3,5-diphenyl-4,5-dihydro-1,2-oxazol-4-yl)methyl aniline)benzene sulfonamide (A6-10). The structure of the synthesized compounds were evaluated by IR, 1H NMR and elemental analysis. All the compounds screened for antitubercular activity. Anti-tubercular activity was carried out by using middle brook 7H9 broth base ( M198 ) medium against Mycobacterium tuberculosis of H37Rv strain. Streptomycin was used as standard drug for comparison.
KEYWORDS: Mycobacterium tuberculosis, anti tubercular activity, aromatic ketone, aromatic aldehyde
INTRODUCTION:
Tuberculosis (TB) is an infectious disease that is caused by a bacterium called Mycobacterium tuberculosis. According to WHO, currently one third of world’s populationi is infected with latent tuberculosis[1]. TB is responsible for deaths of over 2 million people annually worldwide. Moreover enhanced susceptibility to TB in HIV infected population is another serious health problem throughout the world. The increasing problem of Multi-Drug Resistant-tuberculosis has focused on developing new drugs that are active against drug resistant tuberculosis. Isoxazoline derivatives reported wide varieties of activities, antiulcerogenic[2], anti-inflammatory[3], antidepressant[4], antiplatelet[5], antiviral[6], fungicides[7], bactericidal[8], anti -TB activity[9]. The structures of all new compounds were confirmed by their IR, 1H-NMR, Mass spectra and by elemental analysis. This prompted us to undertake an exhaustive investigation of synthesis and evaluation of anti –TB activity of various isoxazoline derivatives.
.
MATERIALS AND METHODS:
Melting point were taken in open capillary tubes and are uncorrected. The purity of the compounds was confirmed by thin layer chromatography using silica gel –G coated plates and spots were located by iodine. Analytical data of C, H and N were within ±0.4% of the theoretical values and their structure were elucidated by IR in KBr on Thermo Nicolet IR-200 spectrometer,1H-NMR specrtra were recorded in DMSO on sophisticated multinuclear FT NMR spectrometer model Avance-II (bruker).
Synthesis of 1,3-diphenylprop-2-en-1-one[10] :
Place a solution of 22 g of sodium hydroxide in 200 ml of water, & 100g (122.5 ml) of rectified spirit in a 500 ml bolt-head flask provided with a mechanical stirrer. Immerse the flask in a bath of crushed ice, pour in 52 g (0.43 mol) of acetophenone, start the stirrer & then add 46 g (44 ml, 0.43 mol) of pure benzaldehyde. Keep the temp of the mixture at about 250 and stirred vigorously until the mixture is so thick that stirring is no longer effective (2-3 h). Remove the stirrer & leave the reaction mixture in an ice chest or refrigerator overnight. Filter the product with suction on a buchner funnel or a sintered glass funnel, wash with cold water until the washings are neutral to litmus. Recrystallise from rectified spirit.
Synthesis of 3,5-diphenyl-4,5-dihydro-1,2-oxazole[11]:
To a solution containing 6 g of the α,β-unsaturated ketone in 140 cc. of methanol was added 5 g of hydroxylamine hydrochloride in 5 cc. of water and 4 g of potassium hydroxide in 20 cc. of water. The potassium hydroxide solution was added slowly. The mixture turned a reddish brown. It was refluxed for two hours. Upon cooling potassium chloride fell out, but was not filtered. The mixture was then poured into 500 cc. of cold water and allow to stand over night, the next day light tan crystals were found to have settled out. They were filtered and recrystallised from methanol.
Synthesis of N-(3,5-diphenyl-4,5-dihydro-1,2-oxazol-4-yl)methyl aniline)-4-ethyl benzoate[12] :
A mixture of compound IV (0.01 mol) in methanol, formaldehyde (0.02 mol), and aromatic anilines [ethyl 4-aminobenzoate] (0.02 mol) was added. The reaction mixture was refluxed for 2-6 h. The solvent was distilled off and poured into ice water, resulting solids were filtered off, dried and recrystallised using appropriate solvents.
Synthesis of N-(3,5-diphenyl-4,5-dihydro-1,2-oxazol-4-yl)methyl aniline)-N-(4-sulfamoylphenyl) benzamide [A 1-5]:
A mixture of compounds V (1 mol) in ethanol and sulphanilamide (1.5 mol) was added. The reaction mixture were refluxed for 8-10 h After reflux evaporate the solvent, resulting solids were dried and recrystallised using appropriate solvent.
Synthesis of N-(3,5-diphenyl-4,5-dihydro-1,2-oxazol-4-yl)methyl aniline)benzene sulfonamide[12] [A 6-10]:
A mixture of compound IV (0.01 mol) in methanol, formaldehyde (0.02 mol), and aromatic anilines [4-amino benzene sulfonamide] (0.02 mol) was added. The reaction mixture was refluxed for 2-6 h. the solvent was distilled off and poured into ice water, resulting solids were filtered off, dried and recrystallised using appropriate solvents.
The antitubercular screening was carried out by Middle brook 7H9 agar medium against H37RV strain. Middle brook 7H9 agar medium containing different derivatives (A1-5 ) & (A6-10), standard drug as well as control. Middle brook 7H9 agar medium was inoculated with Mycobacterium tuberculosis of H37RV strain. The inoculated bottles were incubated for 370C for four weeks. After four weeks they were checked for growth.
SCHEME:
|
Comp |
R |
R1 |
Comp |
R |
R1 |
|
A-1 |
H |
OCH3 |
A-6 |
OH |
CH3 |
|
A-2 |
H |
CH3 |
A-7 |
H |
NO2 |
|
A-3 |
Cl |
OCH3 |
A-8 |
Cl |
Cl |
|
A-4 |
Cl |
NO2 |
A-9 |
OH |
Cl |
|
A-5 |
Cl |
CH3 |
A-10 |
OCH3 |
CH3 |
Table no 1 : Analytical & Physicochemical data of the synthesized compounds A(1-10)
|
Comp. |
Mol. Formula |
Mol. Wt. |
m.p. ° C |
Yield % |
Elemental analysis Calculated (found) |
Rf Value |
||
|
C |
H |
N |
||||||
|
A-1 |
C30H31N4O5S1
|
559.66
|
132
|
87.27
|
64.38 64.73 |
5.58 5.07 |
10.01 10.07 |
0.79
|
|
A-2 |
C30H31N4O4S1
|
543.66
|
141
|
83.33
|
66.27 66.65 |
5.74 5.22 |
10.30 10.36 |
0.83
|
|
A-3 |
C30H31N4O5S1Cl1
|
595.11
|
126
|
83.05
|
60.54 60.96 |
5.25 4.60 |
9.41 9.48 |
0.85
|
|
A-4 |
C29H28N5O6S1Cl1
|
610.08
|
102
|
81.66
|
57.09 57.47 |
4.62 3.99 |
11.47 11.56 |
0.81
|
|
A-5 |
C30H31N4O4S1Cl1
|
579.11
|
124
|
85.96
|
62.22 62.66 |
5.39 4.73 |
9.67 9.74 |
0.86
|
|
A-6 |
C23H26N3O4S1
|
440.54
|
123
|
78.40
|
62.70 63.14 |
5.94 5.30 |
9.53 9.60 |
0.72
|
|
A-7 |
C22H22N4O5S1
|
454.50
|
128
|
77.09
|
58.13 58.40 |
4.87 4.46 |
12.32 12.38 |
0.68
|
|
A-8 |
C22H22N3O3S1Cl2
|
479.40
|
145
|
74.73
|
55.11 55.47 |
4.62 4.02 |
8.76 8.82 |
0.67
|
|
A-9 |
C22H23N3O4S1Cl1 |
460.95
|
136
|
80.61
|
57.32 57.70 |
5.02 4.40 |
9.11 9.18 |
0.63
|
|
A-10 |
C24H28N3O4S1
|
454.56
|
139
|
82.78
|
63.41 63.84 |
6.20 5.58 |
9.24 9.31 |
0.70
|
|
Compd. Code |
IR Bands (cm-1) |
Types of Vibrations |
Compd. Code |
IR Bands (cm-1) |
Types of Vibrations |
|
A-1 |
1599.67 1023.65 1685.80 3343.26 3243.38 2981.66 |
-C=N- Str. -OCH3 Str. -C=O Str. -NH- Str. -SO2NH2 Str. Ar C-H Str. |
A-6 |
1613.22 3240-71 2920.72 2853.60 3388.60 3320.41 2983.62 |
-C=N- Str. -OH Str. -CH3 Str. -CH2- Str. -NH- Str. -SO2NH2 Str. Ar C-H Str. |
|
A-2 |
1631.01 2982.61 1685.74 3422.93 3343.62 2982.61 |
-C=N- Str. -CH3 Str. -C=O Str. -NH- Str. -SO2NH2 Str. Ar C-H Str. |
A-7 |
1598.39 1518.96 2853.14 3209.81 3190.80 2923.20 |
-C=N- Str. -NO2 Str. -CH2- Str. -NH- Str. -SO2NH2 Str. Ar C-H Str. |
|
A-3 |
1598.04 771.54 1026.52 2845.36 1683.57 3373.30 3321.11 2924.10 |
-C=N- Str. -C-Cl Str. -OCH3 Str. -CH2- Str. -C=O Str. -NH- Str. -SO2NH2 Str. Ar C-H Str. |
A-8 |
1626.42 745.30 2849.78 3385.68 3321.40 2922.38 |
-C=N- Str. -C-Cl Str.. -CH2- Str. -NH- Str. -SO2NH2 Str. Ar C-H Str. |
|
A-4 |
1633.09 701.19 1515.08 1685.00 3423.50 3343.70 2925.31 |
-C=N- Str. -C-Cl Str. -NO2 Str. -C=O Str. -NH- Str. -SO2NH2 Str. Ar C-H Str. |
A-9 |
1597.36 747.05 3243.76 2851.16 3384.61 3321.10 2923.56 |
-C=N- Str. -C-Cl Str.. -OH Str. CH2- Str. -NH- Str. -SO2NH2 Str. Ar C-H Str. |
|
A-5 |
1628.27 772.36 2923.91 2845.96 1683.08 3377.12 3339.68 2981-38 |
-C=N- Str. -C-Cl Str. -CH3 Str. -CH2- Str. -C=O Str. -NH- Str. -SO2NH2 Str. Ar C-H Str. |
A-10 |
1597.54 1027.53 2923.91 2845.96 3383.79 3319.90 2980.42 |
-C=N- Str. -OCH3 Str. -CH3 Str. -CH2- Str. -NH- Str. -SO2NH2 Str. Ar C-H Str. |
|
Compd. Code |
d Values in ppm |
No. of Protons |
|
A -4 |
4.05 3.25, 3.37 7.15–7.93 4.62 2.45 9.15 8.6 |
1H of NH–Ar 2H of CH–CH2 16H of Ar–H 1H of CH–Ar 1H of CH–CH2 1H of CO–NH 2H of SO2NH2 |
|
A-8 |
4.0 3.14, 3.38 7.34–7.82 4.60 2.38 8.8 |
1H of NH–Ar 2H of CH–CH2 12H of Ar–H 1H of CH–Ar 1H of CH–CH2 2H of SO2NH2 |
Table no 4 : Antitubercular Activities of the synthesized compounds (A 1 -10)
|
Sl. No. |
Compounds |
5 µg/ml |
10 µg/ml |
15 µg/ml |
|
1 |
A-1 |
S |
S |
S |
|
2 |
A-2 |
R |
R |
R |
|
3 |
A-3 |
R |
S |
S |
|
4 |
A-4 |
S |
S |
S |
|
5 |
A-5 |
S |
S |
S |
|
6 |
A-6 |
R |
R |
R |
|
7 |
A-7 |
S |
S |
S |
|
8 |
A-8 |
R |
S |
S |
|
9 |
A-9 |
R |
R |
R |
|
10 |
A-10 |
S |
S |
S |
|
STD |
Streptomycin |
S |
S |
S |
RESULT AND DISCUSSION:
The 10 new derivatives of N-(3,5-diphenyl-4,5-dihydro-1,2-oxazol-4-yl)methyl aniline)-n-(4-sulfamoylphenyl) benzamide and N-(3,5-diphenyl-4,5-dihydro-1,2-oxazol-4-yl)methyl aniline)benzene sulfonamide were synthesized. The analytical data of the compounds is mentioned in (Table no 1).
The IR spectrum of the compounds (A1 – A10) showed peaks at 1597.36 – 1633.09 cm-1 C=N stretching, 1683.08 – 1685.80 cm-1 C=O stretching, 3209.81 – 3388.60 cm-1 NH stretching (Table no 2). The NMR spectrum of the compound ( A4 ) showed 7.15 – 7.93 (m, 16H of Ar-H), 4.05 (s,1H of NH-Ar), 4.62 (s, 1H of CH-Ar), 2.45 (s, 1H of CH-CH2) (Table no 3).
The synthesized compounds were evaluated for antitubercular activity. The Compounds A-1, A-4, A-5, A-7, A-10 have shown promising antitubercular activity.The compounds A-3, A-8 have shown moderate antitubercular activity. The compounds A-2, A-6, A-9 have not shown antitubercular activity. H 37, Rv strain was used as standard tubercular organism. Streptomycin was used as standard drug.
CONCLUSION:
In the present scheme we have synthesized N-(3,5-diphenyl-4,5-dihydro-1,2-oxazol-4-yl) methyl aniline)-n-(4-sulfamoylphenyl) benzamide and N-(3,5-diphenyl-4,5-dihydro-1,2-oxazol-4-yl) methyl aniline)benzene sulfonamide derivatives. The structures of the synthesized compounds were confirmed by IR , 1H –NMR and CHN analysis. These compounds were screened for antitubercular activity by the std. procedure against std drugs as a reference. Some of these compounds have given promising anti tubercular activity. With suitable molecular modifications of these compounds we can predict promising bioactive molecules in future.
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Received on 07.06.2012 Modified on 09.07.2012
Accepted on 18.07.2012 © AJRC All right reserved
Asian J. Research Chem. 5(7): July, 2012; Page 932-935