Heterocyclic compounds have a wide range of applications but are of particular interest in medicinal chemistry and this improve the discovery and development of much heterocyclic chemistry and methods. The heterocycles are those cyclic organic compounds in which N, O or S elements replaced one or more of the ring carbon atoms. The sulphur and nitrogen atoms are important components of functional materials since heteroatoms present in their rings stabilize ion radical species and extended π-conjugation facilitate in decreasing columbic repulsion [1]. Quinoxalines and thiazines are important heterocycles in medicinal chemistry [2,3].Quinoxaline is one of the benzo-fused six-membered heterocyclesand displays a wide spectrum of potential pharmacological activities and also it is an important part of antibiotic echinomycin [4]. Quinoxaline hold up as a core unit in number of biologically active compounds includes anti-cancer [5], anti-bacterial[6], antifungal, anti-viral [7], analgesic, anti-inflammatory [8] and anti-HIV activity [9]. On the other hand, thiazine and their derivatives are found to be associated with various biological activities such as anti-microbial [3], anti-tumor[10] anti-oxidant [11], calcium channel modulators and anti-pyretic [12]. We have now synthesizes a new heterocyclic systems incorporating both quinoxaline and thiazine substructures from 2-amino-3-quinoxalinethiol whit various α-halo ketones. The resulting thiazino[2,3-b]quinoxaline derivatives were characterized by 1H NMR, 13C NMR, FTIR and Mass spectroscopies.

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