A Facile one–pot Synthesis of Pyrido[3`,2`:4,5]thieno[3,2-d] [1,2,4]triazolo[5,4-a]pyrimidin-5-one

S. M. Riyadh*, M. A. Abdallah, I. M. Abbas and S. M. Gomha

Department of Chemistry, Faculty of Science, University of Cairo, Giza,, e-mail: riyadh1993@hotmail.com, Egypt

Abstract: Two convenient methods for synthesis of novel pyrido[3,2:4,5]thieno[3,2-d] [1,2,4]triazolo [5,4-a]pyrimidin-5-ones 8 were developed. The first route involved the reaction between 2,3-dihydro-7,9-dimethyl-2-thioxo-pyrido[3`,2`:4,5] thieno[3,2-d] pyrimidin-4(1H)-one 3 or its 2-methylthio derivative 4 with hydrazonoyl halides 5 in dioxane under reflux in presence of triethylamine. The alternative route proceeded via reaction of 3 with the appropriate active chloromethylene compounds followed by coupling the products with benzenediazonium chloride which afforded the azo coupling products and then was converted in situ to 8. The reaction mechanism was elucidated and the products were investigated for their biological activity.

 Key Words: pyrido[3`,2`:4,5]thieno [3,2-d][1,2,4]triazolo[5, 4-a]pyrimidin-5-one.

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