Synthesis , antibacterial and surface activity of 1 , 2 , 4-triazole derivatives

Sodium 1-[4-amino-5-mercapto-4H-(1,2,4)triazol-3-yl]heptadecane-1-sulfonate 2 has been used as a new precursor to synthesize some important biologically active heterocycles. Reaction of 2 with carbon disulphide in pyridine and acid chlorides yields the 1,2,4-triazole derivatives 3, 4a and 4b. Condensation of 2 with appropriate aldehydes gives 5a-c which have been cyclized by treating with thioglycollic acid to yield 6a-c. Reactions of 2 with phthalic anhydride and 4methylbenzenesulfonyl chloride gives 7 and 8. In addition, the reaction of 2 with chloroacetaldehyde, phenacyl bromide, urea and chloroacetyl chloride yields 9, 10, 11 and 12, respectively. On the other hand, refluxing 2 with phenyl isothiocyanate gives 13 and 14. All these products have antimicrobial activity and they can be used as surface active agents.


INTRODUCTION
In our series of the synthesis of surface active agents containing heterocyclic moiety (Amin et al., 2004;Amin et al., 2003;El-Sayed et al ., 2005) it is interesting to use 1,2,4-triazole derivatives as new precursor starting material in the synthesis of some Synthesis, antibacterial and surface activity of 1,2,4-triazole derivatives By R. El-Sayed Chemistry Department, Faculty of Science, Benha Unviversity, Benha -Egypt. ref_at@hotmail.com important biologically active heterocycles which constitute an important class of organic compounds with diverse biological activities, including antiparastic, analgesic, antibacterial and antiinflammatory activities (Tayseer et al., 2002;Cansiz et al., 2004;Katica et al., 2001;Li-Xue et al., 2002;Hovsepian., 2004;Wasfy., 2003). A considerable effort has been made in recent years to further develop the synthesis of these nucleus. (Boshra et al., 2002;Kumar et al., 2003;Oganisyan et al., 2004). These derivatives are very attractive heterocyclic systems due to their extensive use in medicine, agriculture and industry (Xin-Ping et al., 2000). In light of the above facts and with a view to obtain new biologically active agents I was encouraged to synthesize a new series of 1,2,4triazole derivatives bearing (long alkyl chain with sulfonic acid hydrophilic center) in a single molecular framework likely to constitute new biologically active anionic surface active agent hopefully possessing good surface properties and expected to have biological activities.

MATERIAL AND METHODS
Melting points are uncorrected. IR spectra in KBr were measured on a Pye-Uncam SP-1000 infrared spectrophotometer on a KBr disk or nujol. The 1 H NMR spectra were obtained on a Varian EM-390-60 MHz spectrometer in DMSO as the solvent. Tetramethylsilane TMS served as an internal reference and chemical shifts are expressed as δ (ppm). Mass spectra were recorded on a G-C/Ms Finning-MAT. Microanalyses were preformed by the Microanalytical Unit at Cairo University. All the compounds gave satisfactory elemental analyses. Thin layer chromatography (TLC) was carried out on silica gel (MN-Kieselgel G., 0.2 mm thickness) and the plates were scanned under 254 nm ultraviolet light. Antimicrobial and antifungal activity testes were carried out at the microbiology Lab., Faculty of Science, Zagazig University, Benha-branch, Egypt. mp = 121-122 °C. IR: ν (cm -1 ) = 3422, 3300 (NH), 2922-2852 (CH in alkyl chain), 1350 (S=O) and 1691 (C=O).

General procedure for preparation of 6a-c
To a solution of Schiff bases 5a-c (0.01 mol) dry acetone thioglycollic acid (0.01 mol) was added. The reaction mixture was refluxed for 3 h. A solid product was obtained after cooling to give the adducts 6a-c which were crystallized from ethanol.
Methode B. Thiosemicarbazide derivative 13 was fused in an oil-bath above its melting point. The product was cooled, treated with ethyl acetate, and filtered. The solid product was crystallized from ethanol to give 14.

Biological activity
The antibacterial activities of some synthesized compounds were determined in vitro using hole plate and filter paper disc methods  against various pathogenic bacteria such as Gram +ve bacteria (Bacillus subtilis, staphylococcus aureus) and gram -ve bacteria (Escher-ichia coli) in addition to fungi as Aspergillus niger was used. The tested compounds were dissolved in 10 % acetone (v/v), different concentrations were chosen (125, 250, 500 µg/ml). A qualitative screen was performed on all compounds while quantitative assays were done on active compounds only.

Foaming properties.
The foaming properties were measured according to Somaya et al. (1998). In this procedure a 25 ml solution (1.0 wt %) was shaken vigorously for 10 seconds in a 100 ml glass stopper, graduated cylinder, at 25 °C. The solution was allowed to stand for 30 seconds, and the foam height was measured.
2.16.5. Emulsification stability. The emulsion was prepared from 10 ml.of a 20 m mol. aqueous solution of surfactant and 5 ml. of toluene at 40 C. The emulsifying property was determined by the time it took for an aqueous volume separating from the emulsion layer to reach 9 ml. counting from the moment of cession shaking (Takeshi, 1970).

Stability towards hydrolysis.
A mixture of 10 m.mol surfactant and 10 ml 0.05 N NaOH were placed in a thermostat at 40 °C. The time it takes a sample solution to be clouded as a result of hydrolysis shows the stability of the surfactant to hydrolysis (El-Sukkary et al., 1987).

Biodegradability
Samples taken daily or more frequently were filtered through Wattmann filter paper number (1) before measuring the surface tension. Surface tension measurements were made periodically each day, on each sample during the degradation test (Eter et al., 1974). Biodegradation percent (D) for each sample was calculated using the following equation: D = [(γ t -γ o ) (γ bt -γ o )] x 100, where γ t = surface tension at time t, γ o = surface tension at zero time, γ bt = surface tension of blank experiment at time t (without samples).
In the present investigation, the condensation of 2 with equimolar amounts of chloroacetyl chloride furnished 12. In view of the known antifungal and antiviral characteristics (Walid et al., 2002;Stankovsk et al., 2000) inherent in substituted thiosemicarbazide derivatives, the synthesis of new compounds incorporating such a group was undertaken. Thus, the reaction of triazole 2 with phenyl isothiocyanate in dimethylformamide at room temperature gave 13. On the other hand, the reaction of triazole 2 with phenyl isothiocyanate by refluxing in dimethylformamide resulted in the corresponding thiosemicarbazide derivative 14 which was also obtained by heating 13 above its melting point. (Scheme 2).

Biological activity
The data indicated that most of the synthesized compounds have remarkable activity and that the tested compounds 2, 6a-c, 10, 9, 12 and 13 were highly active towards the selected pathogens, while the compounds 3, 4a, 4b, 7a-c, 8, and 11 were moderately active towards the different strains of bacteria and fungi as compared with the standard. (Table I).

Surface active properties
The investigation of the surface active properties (surface and interfacial tension, Kraft point, wetting time, foaming height, emulsion stability, and stability against hydrolysis) of 1,2,4-triazole derivatives bearing (long alkyl chain with sulfonic acid hydrophilic center) was carried out at concentration 1 wt % and 20 °C in distilled water. The results are represented in Table II. The biodegradability properties were also determined and are represented in Table III. These products are interesting because these types of anionic surfactants are not common ones. Therefore the traditional procedure was used to follow up the properties.   3.3.2. Kraft point (T kp ). The Kraft point of the prepared anionic surfactants was measured at the temperature where 1% dispersion becomes clear under gradual heating. All the synthesized products are freely soluble in water. In general, T kp measurements proved that, the higher the molecular weight, the higher T kp .Yet, in some cases, this fact may fail due to the presence of retarding groups in the same of molecule. So, in the case of compounds 5a-c, 6a-c, 7a-c and 12 the aryl group may increase T kp compared to the (-SH) group which causes a decrease.

Wetting time.
The products were therefore very effective as wetting agents in distilled water. So, It is hoped that they will find a wide range of applications in the textile industry. The wetting times of the tested compounds were determined by measuring the sinking time in seconds of a gray cotton skin in the surfactant solution. The results show that the products were very effective as wetting agents in distilled water solutions.

Foaming height.
The values of the foaming height were investigated for prepared compounds and the results revealed that the new compounds yield low foam. The low foaming power compounds have applications in the dyeing and auxiliary industries.

Emulsion stability.
Studies are still being carried out on the utilization of surfactants in emulsion formulation, which is of immense importance to technological development. Emulsification is one of the most important properties of surfactants. All the prepared surfactants are good emulsifying agents. They could be useful in dye baths in the textile industry and as emulsion paints.
3.3.6. Stability towards hydrolysis. The results observed that the prepared compounds are moderately stable in a basic medium. Also, anionic surfactants containing heterocyclic moieties recorded high stability.

Biodegradability
The results showed that, biodegradability decreased with increasing molecular wieght of the compound. This indicated that, the more bulky the molecule was, the lower the biodegradability of the surfactants. Also, anionic surfactants containing heterocyclic moiety served the double function of surface active agent and antibacterial activity.

CONCLUSIONS
From the previous results, it may be concluded that all the prepared anionic surfactants have good emulsifiers in a non-edible medium such as insecticides or pesticides.