Syntheses of Some 3 , 5-Diaryl-4 H-1 , 2 , 4-triazole Derivatives and their Antifungal Activity

Syntheses of a series of 3, 5-diaryl-4H-1, 2, 4-triazole derivatives are described. In this present work, 4-amino-3-phenyl-5-p-tolyl-4H-1,2,4-triazole(1) was converted to N,N’-bis[3-phenyl-5-p-tolyl-4H-1,2,4-triazolyl]-1,4-xylenediimine(2) and 3-Phenyl-5-p-tolyl-4-[4-methyl benzylidenamino]-4H-1,2,4-triazole (3) in good yields by treatment with aldehydes OHC-C6H4-CHO and Ar-CHO respectively. The compounds N,N’-bis [3-phenyl-5-p-tolyl-4H-1,2,4-triazolyl]-1,4-xylenediimine (2) and 3-phenyl-5-p-tolyl-4-[4-methyl benzylidenamino]-4H-1,2,4-triazole (3) were reduced with NaBH4 to afford the corresponding compounds N,N’-bis [3-phenyl-5-ptolyl-4H-1,2,4-triazolyl]-1,4-xylenediamine (4) and 3-phenyl-5-p-tolyl-4-[4-methyl benzylamino]-4H-1,2,4-triazole (5) respectively. The newly synthesized compounds were characterized by spectral and elemental analyses. All the synthesized compounds were tested for their antifungal activity against P.oryzae, B. cinerea, A. niger, C. albicans and T. rubrum.


Introduction
The chemistry of heterocyclic compounds continuously to be an explore field in the organic chemistry.The importance of triazole derivative lies in the field that these have occupied a unique position in heterocyclic chemistry due to their antimicrobial activity [1][2][3] .

Experimental
Melting and boiling points were determined on a Gallen Kamp apparatus in open capillaries and are uncorrected.IR spectra (KBr in cm -1 ) were recorded on a Jasco FT-IR 5300 spectrophotometer and PMR spectra (DMSO-d6) on a Varian EM-390 spectrometer using TMS as an internal standard (chemical shift in δ ppm).Mass spectra were recorded on a Jeol JMS-D 300 Mass spectrometer operating at 70 eV.The purity of the compounds was confirmed by TLC using silica gel G and purified by column chromatography.For TLC, Merck silica gel 60 G plate was used.For column chromatography, Merck silica gel 60 (0.063-0.200 mm) was used.The necessary chemicals were obtained from Merck and Fluka.All compounds showed satisfactory elemental analyses.

N,N'-Bis
The corresponding compounds (2) (0.01 mol) was dissolved in 60 mL of dried methanol and NaBH 4 (0.01 mol) was added in small portion of the solution.The mixture was refluxed for 30 min and then allowed to cool.After evaporation at 35 0 C under reduced pressure, the solid residue was washed with cold water.After drying, the solid product was recrystallized from ethanol to yield the compound (4), (

3-Phenyl-5-p-tolyl-4-[4-methyl benzylamino]-4H-1,2,4-triazole (5)
The corresponding compounds (3) (0.01 mol) was dissolved in 60 mL of dried methanol and NaBH 4 (0.01 mol) was added in small portion of the solution.The mixture was refluxed for 30 minutes and then allowed to cool.After evaporation at 35 0 C under reduced pressure, the solid residue was washed with cold water.After drying, the solid product was recrystallized from ethyl acetate to yield the compound ( 5

Antifungal activity
Four compounds were evaluated for their fungicidal activity against P.oryzae, B. cinerea, A. niger, C. albicans and T. rubrum at 1000 ppm, 500 ppm and 100 ppm concentrations, respectively by food poisoning of solidified agar technique [12][13][14] .The inhibitory activities were compared with commercial fungicide Griseofulvin (standard drug) under similar conditions.The mould cultures used were 7 days old.The results are presented in Table 1.The percentage inhibition after the incubation for 24, 48 and 72 h was calculated by following equation: Where, C= Diameter of Fungus colony (mm) in control plates T= Diameter of Fungus colony (mm) in treated plates It is obvious form the fungicidal screening results that the most of compounds have significant fungi toxicity at 1000 ppm against all of five fungi, but the fungi toxicity decreases considerably upon dilution.The result indicates that all these compounds showed very good activity against P.oryzae, B. cinerea, A. niger, C. albicans and T. rubrum.(Table 1).From the above observation it is clear that the 1, 2, 4-triazole derivatives are more active and play a prominent role in the antifungal activity.Control 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

Table 1 .
Evaluation of antifungal activity of the compounds.