Synthesis , Evaluation and Characterization of Some 1 , 3 , 4-Triazole-2one Derivatives as Antimicrobial Agents

A series of novel compounds like 3[(phenyl substituted)-5methyl-1(Benzosulphonylamine)]-1,3,4-triazole-2-ones II(a-f) were synthesized by treating 4-amino-1-phenyl-3-methyl-5-oxo-1,2,4-triazoles with benzene sulphonyl chloride using pyridine as solvent. Similarly by using 4-amino-1-aryl-3-methyl-5-oxo-1,2,4-triazoles and acetic anhydride as starting material 3[(phenyl substituted)-5-methyl-1(acetylamino)]1,3,4-triazole-2-ones III(a-f) were synthesized and also 3[(phenyl substituted)-5-methyl-1(chloroacetyl)]-1,3,4-triazole-2-ones I(a-f) were synthesized by treating 4-amino-1-aryl-3-methyl-5-oxo-1,2,4-triazoles with chloroacetyl chloride in presence of a non-polar solvent like benzene. Elemental analysis, GCMS, IR, and H NMR confirmed the structures of the newly synthesised compounds. The newly synthesized compounds are also screened for their antibacterial, antifungal and antiinflammatory activities.

The triazoles were synthesized from sydnones as starting material were mesoionic in nature (meso + ionic).The aromaticity of these compounds can be explained based on the classical sextet theory.There are a total of seven 2p z -electrons supplied by the atoms which makeup the ring to have sextet electrons in the ring.The yield of triazoles is nearly 75%.Triazoles are potent heterocyclic compounds having antibacterial and antifungal activities.

Scheme 1
The IR spectra of I(a-f) showed characteristic absorption band at 1680 cm -1 is due to >C=O group of side chain and adsorption band at 1722 cm -1 is due to another ring >C=O group.The NH 2 peak appeared in triazoles is disappeared by the formation of 3[(phenyl substituted)-5-methyl-1(chloroacetylamine)]-1,3,4-triazole-2-ones I(a-f).The -NH group in the product is appeared at 3002 cm -1 .
In II(a-f), the IR band corresponds to -NH is appeared at 2932 cm -1 , the -S=O is appearing at 1491 cm -1 , similarly in III(a-f) products the >C=O stretching of amide is at 1548 cm -1 .
The 1 H NMR, LCMS, IR and elemental analysis supported the structure of title compounds.Physical and analytical data of title compound and its other substituted derivatives are given in Table 1, Table 2 and Table 3.

Experimental
All the chemicals were purchased from Merck and used without purification.Analytical TLC was performed on silica Gel F 254 plates (Merck) with visualization by UV light.Melting points were determined in open capillaries on a Thermonik melting point apparatus, Mumbai, India and are uncorrected.The IR spectra (KBr,  max, cm -1 ) were run on Shimadzu-8400 FTIR spectrophotometer. 1 H NMR (δ ppm, CDCl 3 /DMSO-d 6 ) spectra were recorded using Brucker WM-400 spectrometer with TMS as internal standard.Mass spectra were recorded on Micromass Q-TOF and Shimadzu LCMS 2010A Mass spectrometer.Elemental analysis was performed on Thermo Finnigam FLASH EA 1122 CHNS analyzer and was within 0.4% theoretical values.
In II(a-f), the IR band corresponds to -NH is appeared at 2932 cm -1 , the -S=O is appearing at 1491 cm -1 .
In compounds III(a-f), the IR band corresponding to the >C=O stretching of amide is at 1548 cm -1 and -NH stretching is appeared at 3010 cm -1 .

Results and Discussion
Biological activity: All the newly synthesized compounds were screened for their antimicrobial activity by cup plate method at 100 µg/ml concentration in DMF against the Bacterial strains viz., E. Coli & B. Subtilis and also against Fungal strains viz., A Niger and A. Sereus.Norfloxacin for bacteria and Griseofulvin as the reference drugs respectively.All these compounds were less active against the bacterial strains, but some of them showed selective fungal inhibitory activity (Table-4).

1 . Table 1 .
Physical and analytical data of compound I and its other substituted derivatives.

Table 2 .
Physical and analytical data of compound II and its other substituted derivatives.

Table 4 .
Anti-microbial activities of synthesized compounds I(a-f), II(a-f), and III(a-f).