World Applied Sciences Journal 18 (9): 1253-1256, 2012 ISSN 1818-4952 © IDOSI Publications, 2012 DOI: 10.5829/idosi.wasj.2012.18.09.3750 Corresponding Author: Fatemeh Hakimi, Department of Chemistry, Payame Noor University, P.O. Box 19395-3697 Tehran, Iran. Tel: +021-8845638. 1253 Selective Cyclization of 4-Amino-6-Metyl-3-Propargyl Mercapto-1,2,4-Triazin-5-One and 4-Amino-5-Metyl-3-Propargyl Mercapto-1,2,4-Triazol by a Green Hetropolyacid Catalyzed Fatemeh Hakimi, Masoumeh Tabatabaee and Majid M. Heravi 1 2 3 Department of Chemistry, Payame Noor University, P.O. Box 19395-3697 Tehran, Iran 1 Department of Chemistry, Islamic Azad University Yazd Branch, Yazd, Iran 2 Department of Chemistry, School of Sciences, Azzahra University, Tehran, Iran 3 Abstract: Cyclization of 4-amino-6-metyl-3-propargyl mercapto-1,2,4-triazin-5-one and 4-amino-5-metyl-3- propargyl mercapto-1,2,4-triazol derivatives 3 and 4 in the presence of Keggin heteropolyacids, H PW O, 3 12 40 H SiW O H PMo O , H PW O /Sio and lacunary Keggin structure (K PMo W O ) afforded 5 and 7 in 4 12 40, 3 12 40 3 12 40 2 7 2 9 40 high yields and short reaction times. When H PW O catalyzes on Sio made production faster and also 3 12 40 2 resulted more reaction potentially. Key words: Heterocyclization Thiazolotriazine Heteropolyacids 1,2,4-Triazine 1,2,4-Triazole INTRODUCTION by changing the chemical composition. Because of Thiones of nitrogen-containing heterocycles have heterocycles and in continuation of our interest in excited the attention of researchers because of their application of heteropolyacids in organic synthesis [15- synthetic possibilities and useful properties. Many 18], in this article we wish to report our results for the compounds containing sulfur and nitrogen atoms are anti- heterocyclization of 6-alkyl-3-phenacyl-mercapto-1,2,4- inflammatory [1], sedative [2], antibacterial [3, 4], antiviral triazin-5(2H)-one (2) using different keggin type [5, 6], or antitumor [7, 8]. Due to their importance, the heteropolyacid catalysts in various conditions. synthesis of these compounds is interested for the discovery of improved protocols towards milder and high Experimental yielding approaches. In comparison with the liquid mineral Chemicals and Apparatus: All solvents were purchased acids, solid acids could be easily separated from the from commercial sources. Polyoxometalats were prepared reaction mixture by simple filtration with high recovery. according to litterateurs procedures [19, 20]. 4-amino-6- This advantage directly leads to a decrease in of methyl-3-thioxo-1,2,4-triazin-5(2H)-one (AMTTO) and 4- equipment cauterization and environment pollution. amino-1,4-dihydro-5-metyle-1,2,4-triazole-5-tione (AMTT) Among various solid acids, heteropolyacids (HPAs) have were prepared in accordance with literature procedure [21- unique physical-chemical properties. Their acidity is 23]. The IR spectra were recorded on a Shimadzu significantly higher than those of traditional mineral acids. spectrometer 883 (KBr pellets, Nujol mulls, 4000-400 cm-1). Furthermore, HPAs are capable of protonating and H NMR and C NMR spectra were recorded on a Bruker- activating the substrate; and in some cases, HPAs are Avance DRX 400 spectrometer using TMS as an external more effective than usual inorganic acid and the standard. Elemental analyses were performed using a traditional acid catalysts. Therefore, they are widely used Costech ECS 4010 CHNS-O analyzer. as homogeneous and heterogeneous acid catalysts for the synthetic reactions [9-14]. They have very strong Prepare H3PW12O40.6H2O-SiO2: Prepare Brønsted acidity approaching the superacid region and H3PW12O40.6H2O-SiO2(%20) 1.23 g H PW O was this acid-base property can be varied over a wide range dissolved in HO (10 mL), 5 g SiO was added, interesting importance of nitrogen-sulfur containing 1 13 3 12 40 2 2