Synthesis and Biological Evaluation of Fatty Hydrazides of By-products of Oil Processing Industry

Some new 2-alkyl-5-mercapto-1,3,4-Oxadiazoles and 3-alkyl-5-mercapto-1,2,3-4H triazoles were synthesized from hydrazides of acid oil and oil recovered from spent bleaching earth. These newly synthesized compounds were characterized on the basis of elemental analysis and evaluated for biological properties. Certain derivatives exhibited fairly high antibacterial and antifungal activities when compared with streptomycin and immidil used as standard antibacterial and antifungal agents respectively.

average value of reference and test at all the time point is similar then it is irrational to compute weight for calculating similarity factor because the product of weight (w t ) and (R t -T t ) will be zero. Therefore f 2 is equal to 100.
In the new scheme of weight (w t ) calculation, no parameter was decided on an arbitrary ground.
The new approach appears to be more realistic as compared to approach 3. Another advantage of the new method is simple calculation steps than approach 3. Equal stress is given to variability in reference and test formulation in the new approach. The maximum allowable %CV is also considered in the proposed method. It considers within samples (12 units of reference and 12 units of test) as well as between samples (reference and test formulations) variability because of utilization of standard deviation and averages of reference and test formulations at each time points for calculating weight. The use of new method is recommended in deciding equivalence of test product with innovators product. The approach may also find application in selection of a bio-batch. The use of new approach may become a strong  Hydrazides, the acylated derivatives [1] of hydrazine are usually encountered as the simple or monosubsituted (RCONHNH 2 ), or as sym-disubsituted (RCONHNHOR) compounds. The latter have been referred to as sec-hydrazides. Besides being useful for a number of biological properties, hydrazides are important starting materials for a wide range of derivatives utilizable in pharmaceutical products and as surfactants. Hydrazides have been known to be associated with antibacterial [2] , antifungal [3] , anthelmintic [4] and anticonvulsant [5] activities. Various thiosemicarbazide derivatives are reported to possess useful pharmacological properties like, antidepressant [6] , antiinflammatory [7] and analgesic [8] activities. In addition to the antibacterial [9] activities exhibited by several triazole derivatives, they are also known for their fungicidal, analgesic and antiinflammatory [10] activities. Oxadiazoles and their derivatives are well known chemotherapeutic agents and their utility has muscle relaxant, and bacteriostatic [11] are well known. Biological assessment of fatty hydrazide and their derivatives has been the focus of earlier investigative studies [12,13] .
The present work is carried out with a view to impart value addition targets by-products, acid oil and oil recovered from spent bleaching earth (ORSBE) used for soya bean oil. The fatty hydrazides are further derivatized to obtain new antibacterial and antifungal agents.
The by-products of oil processing industries-acid oil and ORSBE were procured from Ashwin Vanaspti Methyl esters of acids from oil were prepared by acid catalyzed esterification using standard method [14] . The esters were purified by distillation under 4-5 mm Hg pressure.
Preparation of fatty hydrazides and their derivatives is schematically represented in Fig 1. For the preparation of fatty acid hydrazides [14] a solution of fatty acid esters (0.1 M) in ethanol (150 ml) was mixed with hydrazine hydrate (95%, 0.2 M) was added. The reaction mixture was refluxed for 3-4 h. It was cooled, and the solid separated was collected, washed and recrystallised from ethanol.
For the preparation of 2-alkyl-5-mercapto-1,3,4oxadiazole [15] a solution of a fatty acid hydrazide (0.01 M) in 10 ml of ethanol, a solution of carbon hydrazides of acid oil and oil recovered from spent bleaching earth. These newly synthesized compounds were characterized on the basis of elemental analysis and evaluated for biological properties. Certain derivatives exhibited fairly high antibacterial and antifungal activities when compared with streptomycin and immidil used as standard antibacterial and antifungal agents respectively.
Key words: Acid oil, oil recovered from spent bleaching earth (ORSBE), oxadiazoles, triazoles, hydrazides, antibacterial, antifungal, streptomycin, immidil disulfide (2 g) in 3 ml of water and 1 g of potassium hydroxide were refluxed for 7-8 h until the H 2 S is ceased. The contents were cooled and acidified with dilute hydrochloric acid. The separated solid was filtered, collected, washed with water, dried and recrystallised from ethanol.
For the preparation of fatty acid thiosemicarbazide [16] a solution of a fatty acid hydrazide (0.02 M) in methanol (50 ml), potassium thiocynate (0.03 M) and hydrochloric acid 3 ml were mixed added with constant stirring. The mixture was immediately evaporated to dryness on a steam bath and heated for an additional hour with another 50 ml ethanol. The resulting solid was treated with water, little ethanol and recrystallised from ethanol.
For the preparation of 2-alkayl-5-amino-1,3,4oxadiaazole [14] a solution of thiosemicarbazide (0.01 M) in 15 ml of ethanol was added to a solution of sodium hydroxide (5 ml, 5N) with cooling and stirring. To this clear solution, a solution of I 2 /KI was added till permanent tinge of iodine persisted at room temperature. The mixture was immediately refluxed and more I 2 /KI was added till permanent tinge was obtained. The mixture was then cooled and poured into ice-cold water; the solid that separated was collected by filtration, washed with water and with dilute thiosulfate solution and again with water. The solid was dried and recrystallised from absolute ethanol. The melting point, nitrogen content and percent yield of the compound is given in Table 1.
Characterization of synthesized compounds was conformed by IR. Mercaptotriazoles and aminooxadiazoles showed band at 3100 cm -1 for NH group. The C=N stretching as observed at 1600 cm -1 . The mercaptooxadiazoles showed strong band at 1160 cm -1 for C=S and absence of band around 2550-2600 cm -1 . This showed that this compound existed in thione form rather than thiol.
The hydrazides and their derivatives were tested for anti bacterial activity against Bacillus subtilis and Escherichia coli and antifungal activity against Aspergillus niger by agar-agar cup method [18] . Streptomycin and immidil were used as standard antibacterial and antifungal agents respectively.
It can be observed that (Table 1) upon cyclization to thiosemicarbazides, 2-alkyl 5-mercapto 1,3,4 oxadiazoles and 2-alkyl-5-amino-1,3,4-oxadiazoles, the melting points are decreased and are lower than that of the original hydrazide from which they are derived. However, the melting point increase is observed when the fatty hydrazides were cyclised to 3-alkyl-5-mercapto-1,2,4-4H triazoles with latter showing higher melting point than that of the former. This is in agreement with results of the synthesis work of some fatty hydrazide derivatives conducted by Badami et al. [19] and by Daulatabad et al. [20] . They also reported similar trend of increase in melting point for 3-alkyl 5 mercapto-1,3,4-4H triazoles of different fatty hydrazides and increasing melting points for oxadiazoles of the two fatty hydrazides as compared to respective fatty (oleic and linoleic) hydrazides.