Synthesis and Characterization Antifungal Fluorine Substituted Fused Heterobicyclic Nitrogen Systems Containing 1,2,4-triazine Moiety

Synthesis of some new full fluorinated heterobicyclic nitrogen systems containing 1,2,4-triazine moiety (4-10) have been deduced from heterocyclization of 6-(2'-trifluoroacetylamino)phenyl-3-(4'-fluorophenyl-1,2,4-triazin-5-one (3) with active oxo / halo-compounds. Structure of the products have been established upon their elemental and spectral date. Most of these systems exhibited a good to moderate antifungal activities. Keyword: Synthesis, full fluorinated heterobicyclic, antifungal


Introduction
The introduction of fluorine atoms to functionally 1,2,4-triazines improve their physical, chemical and biological, medicinal properties.Most of fused heterobicyclic nitrogen systems containing 1,2,4-triazine moiety exhibit a good biocidal activity which may be formed of biodynamic systems.Thus, the present work tends to synthesize of full fluorinated fused heterobicyclic nitrogen systems starting from 1,2,4-triazine moiety in view of their antifungal activities.
Presence of both active methylene and /or amino groups in the structures of 6&7 was confirm from condensation with arylaldehyde (AcOH) to give the arylidene 8 and /or the shiff base 9 (Scheme 3).

Materials and Methods
Melting points determined on an electrothermal Bibby Stuart SMP3 (UK) Scientific melting point apparatus and are uncorrected.The infrared (IR) spectra recorded on Perkin-Elmer RXI FT-IR infrared spectrophotometer using the KBr pellet technique.Electronic absorption spectra were recorded in DMF on Shimadzu UV-Visible 3101 PC spectrophotometer. 1 H NMR spectra recorded on a Bruker DPX-400FT-NMR spectrometer at Cairo-University, Egypt.Using tetramethylsilane as the internal standard DMSO-d 6 as a solvent (Chemical shifts in δ, ppm). 19F-NMR Spectra determined at 84.25 MHz using hexafluorobenzene as a solvent.Splitting patterns were designated as follows: s: single; m: multiple; Mass spectra measured on a GCMS-Q 1000 Ex spectrometer.Elemental analyses were performed on a 2400 Perkin Elmer Series 2 analyzer and the found values within ± 0.4% of the theoretical values.Follow up of the reaction and checking the homogeneity of the compounds made by TLC on silica gel-protected aluminum sheets (Type 60 F254, Merck).Compounds 1&2 were prepared according to reported method.

Results and Discussion
IR spectra of all the synthesized compounds recorded a true-carbonyl groups at ~1700 cm -1 with other at 1250 cm -1 for C-F, while that of 3 showed a lack's of C=S group.IR spectra of compounds 4-7 exhibited a second pseudo C=O groups attribute to C=O & C-OH group at 3500~3400 cm -1 .
Mass fragmentation pattern of compound 4 as shown in Figure 1.Presence of OH groups in the compounds 5&6 is due to adjacent of CH 2 to C=O .Former structure of 5&6 is more stabilized skeleton due to the enolization formed towards aryl groups.
H 1 NMR spectra of all the new synthesized compounds showed a different resonated signals of aromatic proton at 8~6.8 ppm with a peak at 6~5 ppm attribute to CH 2 protons of compounds 5&6.On other hand, H 1 NMR spectra these compounds 8&9 recorded the presence of exocyclic CH= protons at 9.8& 8.5 ppm with lack's of CH 2 protons.It is interest that the interaction between compound 3 and chloroacetonitrile in reflux DMF via elimination of Cl ions followed by cycloaddition of NH (triazine) to C ≡ N group yielded the 3-amino-1-(4'-fluorophenyl)-6-(2'-trifluoroacetamidophenyl)-imidazole[2,3-b]-1,2,4-triazin-7-one (7).IR of 7 showed the presence of NH 2 group with as lacks of C≡N group.H 1 NMR spectra give us a supported the structure by recorded the presence of CH= (imidazole) at 8.38 ppm inaddition to both NH, NH 2 and aryl protons at 12.5, 3.6 and 7.7-6.8ppm, respective.Formation of compound 7 may be as shown in the Figure 3.
Former structure of compound 10 was deduced from both correct elemental analysis and that spectral measurements.Thus, IR spectrum showed at 3400-3300 cm -1 attribute to NH -OH functional groups, in addition at 1700, 1660, 1620-1590 cm -1 for 2C=O and CO-NH groups with at 1480 and 1250 cm -1 to aliphatic and C-F groups.H 1 NMR spectrum of 10 recorded the resonated signal at 13.42, 9.62, 7.7-7.4,7.37-6.59ppm for NH, OH, aromatic protons with at 3.67-3.36ppm attribute to CH 2 protons.Mass fragmentation pattern recorded the molecular ion peak with introduction of one mole of H 2 O with a base peak at 96 (Figure 2).

Antifungal Activity
One from the important roles of 1,2,4-triazinones is an enzymatic (cellobiase) effect is on the fungi.Thus, the new synthesized full fluorinated fused heterobicyclic nitrogen systems containing 1,2,4-triazinone moiety have been evaluated as cellobiase agents by used the method described [15] .DMF used as solvent and control towards the selected fungi, Aspergillus nidulans, then added the mixture of enzyme solution with the substrate (cellobiase) dissolved in citrate phosphate buffer at pH 4.8 and incubated at 50 ℃ for one hour.The related reducing sugar was estimated colorimetrically at 540 nm as an indication for the enzyme activity.3,5-Dinitrosalicylic acid (DNS) is used in colorimetric determination of reducing sugars and to analyze glycosidase (glycoside hydrolase) activity by quantitation of enzymatically released reducing sugar.The results obtained recorded in the table 1.We can be conclude that increasing the reducing sugar in the case of compounds 3& 7 at high concentration, and in the case of compounds 4 at low concentration is due to the presence of biodynamic systems with CF 3 &CF.

Conclusion
The novel full fluorinated imidazole /pyrimido-1,2,4-triazinones were synthesized and evaluated as cellobiase activity by use Aspergillus nidulans fungi.It has been an important research organism for studying eukaryotic cell biology for over 50 years, being used to study a wide range of subjects including recombination, DNA repair, mutation, cell cycle control, tubulin, chromatin, nucleokinesis, pathogenesis, metabolism, and experimental evolution.werethe compounds 3,7&10 exhibit a large effect towards a reducing sugar.

Table 1 .
Effect on cellobiase activity produced by A spergillus nidulans