Department of Applied Sciences, Chandigarh Engineering College, CGC, Landran, Mohali, Punjab, India
Received Date: April 26, 2017; Accepted Date: May 02, 2017; Published Date: June 09, 2017
Citation: Mishra K (2017) Synthesis and Biological Evaluation of 2-Aryl - 6, 7-Difluorophenyl-1,3,4-Oxadiazolo (3,2-a) (1,3,5)-Triazine-5-(6H,7H)-Thiones. Chem Sci J 8: 153. doi: 10.4172/2150-3494.1000153
Copyright: © 2017 Mishra K. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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2-Aryl-6,7-difluorofenyl-1,3,4-oxadiazolo (3,2-a) (1,3,5)- triazine-5-(6H,7H)- thiones (2a-j) have been orchestrated by the cyclo expansion of para-fluorophenyl 4 –fluoro phenyl isothiocynate and 2-(4-fluorobenzylidine) to (1a-j) 2-amino - 5-phenyl-1,3,4-oxadiazole in dry toluene all the integrated compounds were very much described by their elemental analysis and spectral data. The integrated compounds have been screened for their antifungal action against Phytophthora infestans and Colletotrichum falcatum. Results demonstrated that greatest antifungal activity was appeared by the compounds 2b, 2c, 2g and 2h. These compounds demonstrated 99%, 98%, 99% and 97% hindrance of Phytophthora infestans and 97%, 96%, 98% and 97% Colletotrichum falcatum at 1000 ppm respectively.
Fungitoxicity; Oxadiazole; Triazine; Thiones
A few 1,3,4-oxadiazole derivatives are known not different kind of valuable natural exercises including herbicidal , fungicidal [2,3], bactericidal , insecticidal , etc. Perhaps toxophoric significance of which have been all around pushed in numerous pesticides [6,7]. Numerous sorts of 1,3,5-triazine derivatives have significance in horticulture as herbicides and fungicides of these, Simanize (1) [2-chloro- 4,6-bis (ethyl amino) - 1,3,5-triazine], Atrazine [2-chloro - 4-ethylamino- 6-isopropylamino-1,3,5-triazine], Prometryne [2-methylthio-4,6- bis (isopropyl amino)- 1,3,5-triazine], Ametryne [2-Methylthio-4- ethylamino-6-(isopropylamino)- 1,3,5-triazine], Dyrene [2,4-dichloro- 6-(2-chloroanilino)- 1,3,5-triazine] and Methoprotryne [2-Methylthio- 4-isopropylamino-6(3-methyoxypropylamino)- 1,3,5-triazine] are all the more remarkable. This significance of 1,3,4-oxadiazole derivatives and 1,3,5-triazine derivatives have incited us to synthesize. Some novel title compounds (2a-j). Thus, antifungal action of synthesize compounds have been screened against growths Phythophthora infestans and Colletotrichum falcatom.
Melting points were taken in open capillary tubes and are uncorrected. The IR spectra were recorded in KBr on Perkin- Elemer-720 spectrophotometer. The 1H NMR spectra were recorded in CDCI3 on Varian A-60D spectrophotometer. The chemical shifts are recorded in ppm downfield from TMS, which are utilized as an inner standard (Figure 1).
Synthesis of compounds (2a-j)
2-(4-fluorobenzylidine amino)-5-phenyl-1, 3, 4-oxadiazole (1aj): A mixture of 2-amino-5-phenyl-1,3,4-oxadiazole 0.02 mol and 4-fluorobenzaldehyde 0.02mol in total ethanol was refluxed for 4 hrs. and separated while hot. The filtrate after cooling outfitted the wanted item which was recrystallized from ethanol as yellowish needles. All the prepared compounds very much concurred with their antifungal information.
7-(4-Fluorophenyl-6,7-dihydro-2-phenyl-6-fluorophenyl)- 1,3,4-oxadiazolo(3,2-a)-s-triazine-5-thione (2aj): A mixture of 2-(4-fluorobenzylidine) amino-5-phenyl-1,3,4-oxadizole 0.01mol and 4-fluorophenyl isothiocynate 0.01mol) was refluxed in dry toluene for 6 hrs. What’s more, the dissolvable was refined of under decreased weight. The residue thus acquired was washed with little measures of ethanol took after by water and the product was recrystallized from ethanol was sparkling yellowish needles. Yield, melting point, molecular formula and elemental analysis of this and in addition that of alternate compounds of this class are recorded in Table 1.
Table 1: The Yield, melting point, molecular formula and elemental analysis of 7-(4-Fluorophenyl-6,7-dihydro-2-phenyl-6-fluorophenyl)-1,3,4-oxadiazolo(3,2-a)-s-triazine- 5-thione (2a-j) and in addition, alternate compounds of this class are shown below.
The compounds (2a-j) were screened for their antifungal movement against Phytophthora infestans and Colletrotrichum falcatum by known technique at the three concentrations Viz., 1000, 100, 10 ppm. The screening information of compounds is recorded in Table 2. Results were contrasted with commercial fungicide DithaneM-45 tested under similar conditions. The percentage inhibition has been calculated by the formula:
|Comp. No.||Ar||Average % inhibition after 96 hours|
|Phytophthora infestans||Colletotrichum falcatum|
|1000 ppm||100 ppm||10 ppm||1000 ppm||100 ppm||10 ppm|
Table 2: Antifungal activity of compounds (2a-j) and Dithane M-45.
% of inhibition=(C-T) × 100/C
Where C and T are diameter (in mm) of fungus colony in control and treated plates respectively.
The 2-Aryl-6,7-difluorofenyl-1,3,4-oxadiazolo (3,2-a) (1,3,5)- triazine-5-(6H,7H)- thiones compounds were screened against Phytophthora infestans and Colletrotrichum falcatum for antifungal activity and their screening data have been summarized in Table 2. Perusal of the screening results demonstrates that all the tested compounds (2a-j) hindered more than 65%growth of the both the test parasites at 1000 ppm concentrations of these, the most dynamic compounds 2b and 2g showed the fungicidal action almost equivalent to that of Dithane M-45 at 1000 ppm concentrations, and restrained 40-44% development of the contagious species even at 10 ppm concentrations. The screened compounds 2b and 2g were highly harmful to Phytophthora infestans and Colletrotrichum falcatum at higher concentrations (1000 ppm) the general results are not all that empowering as one would anticipate from the combined execution of the two boilable nuclei 1,3,4-oxadiazole and s-triazine this may be credited to the halfway immersion in the s-triazine nucleus resulting about the loss of planarity of the oxadiazolo -s-triazine ring system. This assumption is bolstered by the before perception that minimal size and planarity of molecule frequently improve its pesticidal activity. It is in any case, critical that the presentation of chloromethoxy and methyl groups in aryl moiety of these compounds tend to contention the growths fungi toxicity and that presentation of methoxy or methyl group at ortho position is more viable than that para-position. Likewise, the presentation of chloro group. Fungicidal activity changed imperceptibly with the fungal species.
The authors are very thankful to the Director, CDRI, Lucknow for providing basic, unearthly information and to the Director, IARI, New Delhi for lab facilities to evaluate antifungal activity.