Synthesis of Novel Heteropolycyclic Nitrogen Systems Bearing Fluorine Substituted Pyrazolo [ 3 , 4-d ] Pyrimidine Derived from Polyfunctional π-Acceptor Compounds and Guanidine as Fungicidal Probes

Novel heteropolycyclic nitrogen systems bearing fluorine substituted pyrazolo[3,4-d] pyrimidine moiety have been synthesis by the interaction between N’-heteroaryl guanidine 4 with polyfunctional π-acceptors in different media and condition. The structures of the synthesis compounds were established by spectroscopic analysis and evaluated as antifungal probes in various concentration.


Results and Discussion
Ortho diamines are active substrates for the building of a new heterocyclic nitrogen system [13].In the case of unsymmetrical diamines, the substituents influence the initial participation of a particular amino group in the reaction, resulting in chemoselective products.In addition, the more electron withdrawing will be attacked firstly by primary amine [14].Accordingly, the present work studies the interaction between N'-heteroaryl guanidine 4 with various polyelectron withdrawing centers in different media and conditions.
As recently, the synthesis of pyrazolopyrimidine moiety bearing other heterocyclic systems as bioactive semidrugs was reported through a type of nucleophilic attack toward a move positive electrophilic center followed by cycloaddition reaction [1] [2] [17] [18] [19] [20], this investigation was focused on the synthesis of novel fluorine substituted heteropolycyclic nitrogen systems containing a pyrazolopyrimidine moiety in view of their cellobiase activity towards some fungi.
The structure of the products were deduced from correct elemental analysis and their spectral measurements.The reagents used prepared according to Abdel-Rahman et al. [13] [14].
IR absorption spectral study of the obtained systems 6, 7, 9, 11, 13, and 15 give us a good indication about their structural.
IR spectra of compound 6 recorded γ at 3200 of NH 2 , while that of 7 showed both =NH and NH at γ 3362 and 3160 cm −1 .Compounds 6 and 7 showed γ at 3038, 3060 for aromatic CH and γ at 2927, 2286 for aliphatic CH and γ at 1580, 1581 for C=N, and γ at 1341, 1321 for symmetric and asymmetric NO 2 , and γ at 782, 746 for C-F bands.Also compound 6 showed γ at 1128 for C=S.
Additionally, the IR spectrum of both compounds 9 and 11 was recorded γ at 2220 for CN (9) and γ at 3363, 1694 cm −1 for OH and C=O functional groups International Journal of Organic Chemistry On the other hand, 1 H NMR spectra of compounds 13 and 15 showed only one =NH protons at approximately 11.0 and 10.50 ppm.
Focused on function group 13 C NMR spectra of compounds 6 and 7 showed at δ 182 -185 ppm respectively for C=S carbons, while that of 9 and 11 exhibits δ at 150 and 162 ppm for CN and C=O.
Finally, mass spectral study of some isolated heterobicyclic nitrogen systems reported a M + with the two major bulky fragments which undergo farther fragmentation gave the selected base peak at m/e 95 as 4-fluorophenyl ion (11 and 15) (Figure 1 and Figure 2).

Antifungal Activity (Cellobiase)
Due to the medicinal, pharmacological and biological properties of fluorine bearing fused heterobicyclic nitrogen systems the present word tends to evaluate the new fluorine substituted heterobicyclic nitrogen systems as enzymatic affects on the cellobiase produced by fungi [21] [22] [23].The in vitro antifungal activity of the new fluorinated systems obtained via inhibition of mycelial growth of Penicillium italicum, Helimenthosporiumsatium, Pythium deberyanum and Fusarium solani in methanol and sterile potato dextrose agar (PDA) [23].
The fungi toxic activity of the synthesis compounds are tested on P. italium.A Discs of orange rinds (3 × 3 cm) were removed from orange fruits.The discs were further sterilized by 70% ethanol, the rinds were treated with the tested compounds.The treated discs were allowed to dry and were artificially inoculated with spots of P. Itlaicum.The Commercial thiobendazol-2-(4-thiazolyl) benzimidazole (TBZ) Figure 3 was used as control.
The result percentage of rotted discs were evaluated after one weeks Table 1.Prevention of blue mold development the action of new fluorinated systems obtained on the decay control on rind discs is present in Table 2.The results indicate that only compound 15 gave good result in comparison with control.On the other hand, compounds which had the same higher ED 50 values did not prevent the decay at all concentration used.According to the Table 1 and Table 2 we suggest the following conclusion:  The antifungal activity of tested compounds based on ED 50 are 15 > 11 > 9 > 6, 7 > 13.  Compound 15 gave a good activity in comparison with control TEZ especially at 4000 µg•ml −1 may be due to the higher effect of CF 3 groups on the biologically sensitivity of tested fungi. The compounds which had the same or higher ED 50 values did not prevent the decay at all the concentrations used.

Conclusion
In conclusion, this study provides a short and reasonable low cost route to performance N-substituted guanidine towards some α, β, γ-polyfunctional reagents in different conditions to contribute fused heteropolycyclic nitrogen systems as antifungal probes.These compounds have been tasted as antifungal activity, which showed the compounds had the same higher ED 50 values did not prevent the decay at all concentration used.The compound 15 has a rich F-atoms exhibited a highly antifungal activity in comparison with control Thiobendazole (TBZ) which can be effective on fungal disease in orange tree.

Experimental
Melting points determined by an electrochermal Bibly Sturat Scientific melting point sample (UK).A Perkin Elmer Model RXI-FT IR system 55,529 used for IR spectra of the prepared compounds (cm −1 ).A Bruker advance DPX 400 MHZ model uses TMS as internal standard was used for recording the 1 H and 13 C NMR spectra of the compounds on deuterated DMSO-d6 (ppm).Elemental analysis was performed in micro analytical Center of Cairo University, Cairo, Egypt.
The common organic reagents 5, 8, 10 and 12 were obtained according to the reported methods [11]
inhibition of mycellal growth expressed.Table 2. Effect of new fluorinated pyrimidine on prevention of disease development on rinddiscs.Compound No. Percentage of decayed discs at different Conc.(µg•cm −1 International Journal of Organic Chemistry

Table 1 .
Antifungal activity of new fluorinated systems toxicity index.