SYNTHESIS AND CHARACTERIZATION OF

1. SYNTHESIS AND CHARACTERIZATION OF UNSYM-2,4-DIAZA-1,3,5-PENTANETRIONE COMPOUNDSChike L. Orjiekwe, Saheed A. Solola and Theodora E. ObiDepartment Of Chemistry, College Of Natural And Applied Sciences, Igbinedion University, Okada Edo State, Nigeria

2. ABSTRACT Unsym-2,4-diaza-1,3,5-pentanetrione compounds were prepared from urea as precursor by refluxing urea with cinnamoyl chloride under nitrogen in absolute ethanol for 3 hours to form cinnamoyl urea which was subsequently refuxed with crotonoyl chloride, benzoyl chloride and acetyl chloride respectively. The hot supernatant mixture was cooled in ice block and the crude white solid obtained were recrystalized from methanol.

3. The pure solid white crystals obtained were characterized by micro-elemental analysis, UV-Visible, FT-IR and NMR spectrophotometric techniques. The results shows the presence of 1,3,5-pentanetrione moiety in all which confirm the formation of the compounds. These compounds are potential intermediates for polymeric plastic industries as they can be polymerized via the double and carbonyl bonds by step-growth condensation and catalyzed addition polymerizations.

4. Introduction 1) Urea and its compounds have versatile usage as fertilizers, feed supplements, very good plant growth regulators and as intermediates in plastic and drug manufacture ( Shanhnaz et al. 2012, Yonova and Stoilkova 2004 and Orjiekwe et al. 2013) 2) In some of our previous works, we reported the preparation of symmetrical 2,4-diaza–1,3,5–pentanetrione compounds using urea as precursor (Obaleye et al 1995 and Orjiekwe et al 2013). These include:

5. NH NH CH=CH CH=CH C llO C llO NH NH CH3 CH=CH CH=CH-CH3 C llO C llO (i) 1,5-dicinnamyl-2,4-diaza-1,3,5-pentanetrione (dcdpt) (dcdpt) (ii) 1,5-Diallyl-2,4-diaza-1,3,5-pentanetrione (dadpt) dadpt

6. 3) These compounds have been shown to possess good fungicidal and antibacterial properties and have good ligational properties to the transition metals (Shanhnaz et al. 2012, Yonova and Stoilkova 2004 and Orjiekwe et al. 2013) In this report we are looking at the preparation and characterization of unsymmetrical 2,4-diaza-1,3,5- pentanetrione compounds and their probable potential uses. 5) All these compounds are potential intermediate for preparation of polymeric plastics as it is possible to polymerize them through step-growth polymerization or catalytic polymerization through the double bonds and the carbonyl bonds

7. Experimental methods The reagents used for this work are Aldrich products and are all of analytical grades. They include Urea, cinnamoyl chloride, benzoyl chloride and acetyl chloride. The compounds were prepared by employing the techniques of previously reported methods by Orjiekwe et al 2013 and Obalaye et al 1995 and 2000. This involves the refluxing of 7.6g (100 mmols) of urea with 16.8g (100 mmoles) of cinnamoyl chloride in ethanol until the evolution of HCl gas seizes. The hot supernatant solution was cooled in an ice bath overnight and the white solid product formed was collected by filtration. The product was washed with petroleum ether, sodium bicarbonate solution and later recrystallized from aqueous ethanol. Pure crystals of the cinnamoyl urea formed were then stored and later used for the following reaction as follow: 100 mmoles of the pure cinnamoyl urea was separately refluxed under nitrogen gas with 100 mmoles each of crotonoyl chloride, benzoyl chloride and acetyl chloride respectively in dry benzene for a period of 4 hours until the evolution of HCl gas seizes.

8. Characterization The structure of the products were elucidated by (i) Melting point determination using Gallen kamp electrothermal melting point apparatus (ii) Ultraviolet absorption bands using UV-visible spectrophotometer model unican 400/360 (iii) Infrared absorption spectrum obtained using FT-IR model unican E.M 360 (iv) Rf-values

9. Result Physical and spectral property

10. DISCUSSION All the compounds are white and crystalline with distinct sharp melting points different from any of the starting materials supporting the formation of the compounds The selected infrared and ultraviolet bands for characterization of the compounds are mainly due to the stretching bands (N-H), (C=C), (C=O), (C=N) and strong bands were observed for the carbonyl stretching bands (N-H), (C=C), (C=O), (C=N) and deformation bands (N-H) (Obalaye et al 2000). About three strong bands were observed for the carbonyl stretching bands (C=O) within the range 1721 - 1650 cm-1 which is due to the presence of 1,3,5-tricarbonyl systems in all the compounds. Also the ultraviolet spectra gave two peaks around 220nm and 293-284nm in all the compounds which are assigned to →* and n→* intra-ligand transition bands of the 1,3,5-tricarbonyl moiety in all the compounds Penland et al. The result of melting points. Rf-values, infrared and ultraviolet spectra study corroborate with previous studies and further support the formation of the new compounds. The overall equations for the reactions and the tentative structures proposed for the compounds are as follows: .

11. H2N NH2 CH=CH Cl + + Cl CH=CH – CH3 C llO C llO C llO NH NH CH=CH 1 3 5 CH=CH-CH3 C llO C llO 2 4 C llO Cl H2N NH2 CH=CH + Cl C llO C llO C llO + NH NH CH=CH C llO C llO C llO i 1 –cinnamyl-5-crotonyl-2-4,diaza-1,3,5-pentanetrione (ccdpt) ii Cinnamoyl Chloride Benzoyl Chloride 1 –cinnamyl-5-benzyl-2,4-diaza-1,3,5-pentantrione (cbdpt)

12. t Cl H2N NH2 CH3 CH=CH + + Cl C llO C llO C llO NH NH CH=CH CH3 C llO C llO C llO iii 1-cinnamyl-5-methyl-2,4-diaza-1,3,5-pentantrione (cmdpt) Efforts are progress to run micro-elemental analysis and proton NMR on the compounds to fully confirm the structure of the compounds.