Synthesis of various S-alkylated derivatives of newly synthesized tricyclic selenium containing heterocyclic system

Selenium is a micronutrient essential for mammals. It plays a crucial role in the mammalian defense system against oxidative stress, since it is essential for the activity of glutathione peroxidase (GPx). It is also essential for the activity of various enzymes such as thioredoxin reductase, iodothyronine deiodinase, selenophosphate synthetase and selenoprotein P [1]. Moreover, some organoselenium compounds are known as effective insecticides, microbicides [2], prooxidants [3] and antimycobacterial agents [4].Due to our interest for the synthesis of selenophens and selenolocondenced heterocyclic systems, in the present protocol, selenopheno[3,2-d]pyrimidine (1) was synthesized and subsequently treated with POCl3 and hydrazine hydrate to give compound (2). The hydrazinated compound (2) on treatment with CS2 and subsequently various alkyl halides in the presence of NaH in DMF, converted to the corresponding desired S-alkylated selenopheno[2,3-e][1,2,4]triazolo[4,3- c]pyrimidines (3a-e).