876 Novel Synthesis of 1,3-Thiazine and Pyrimidinethione Derivatives from (1-Aryl ethylidene)hydrazinecarbothioamides and Tetracyanoethylene Vol 53 Alaa A. Hassan, a * Yusria R. Ibrahim, a Essmat M. El-Sheref, a and Stefan Bräse b a Chemistry Department, Faculty of Science, El Minia University, 61519 El Minia, A. R., Egypt b Institute of Organic Chemistry, Karlsruhe Institute of Technology, Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany * E-mail: alaahassan2001@yahoo.com Received June 25, 2014 DOI 10.1002/jhet.2350 Published online 2 July 2015 in Wiley Online Library (wileyonlinelibrary.com). 1,3-Thiazine-5,6,6-tricarbonitrile and 2-thioxo-2,3-dihydropyrimidine-4,5-dicarbonitriles derivatives were synthesized via interactions between (1-aryl ethylidene)hydrazinecarbothioamides and tetracyanoethylene to give the derivatives of tetracyanoethane and tricyanovinylation intermediates, followed by heterocyclization. The structures of the products have been confirmed by different spectroscopic analyses. A rational for the formation of the products is presented. J. Heterocyclic Chem., 53, 876 (2016). INTRODUCTION One of the most versatile organic is tetracyanoethylene (TCNE) that is used in many different reactions [1–5]. It is highly electron-deficient and strongly electrophilic. TCNE is a good dienophile, possessing good leaving groups and can act as oxidizing agent [6–8]. Furthermore, TCNE perform powerful electron acceptor forming charge-transfer com- plexes with various donors [4,9,10] or it can participate in pericyclic chemistry in Diels–Alder reactions [11] or as enophile in [2 + 2] cycloadditions reactions [2]. Also, it can act as an umpolung source of dicyanomethylene [12,13]. The addition of nucleophiles to the double bond of TCNE, subsequently loss cyanide afforded tricyanovinylation inter- mediates [14–16], which is the common reaction. On the other hand, direct addition to one of the nitrile groups can also occur but is less frequent [17,18]. Various heterocyclic systems such as pyrazoles and pyrimidine derivatives were synthesized upon the reaction of TCNE with substituted hydrazones or 2-amidines, respectively [19]. In the light of this and owing to the importance of TCNE, here, we have described the syn- thesis of new 1,3-thiazine and pyrimidine derivatives. 1,3-Thiazine derivatives have been reported to exhibit a variety of biological activities like antibacterial [20], anti- fungal [21], antitubercular [22], and anti-inflammatory [23]. Synthesis of 1,3-thiazines has been realized by vari- ous methods [24]. For example, β-chlorovinyl ketones and thioamides in the presence perchloric acid [25] or S-alkylthiocarbamates with α,β-unsaturated ketones [26]. Compounds containing pyrimidine nucleus play an important role in life science studies [27–29]. 3,4- Dihydropyrimidinethione is used as a test system for detect- ing tumor growth, on the ultra-structure and function of Mauthrer neurons (MN) [30]. Thiourea derivatives consid- ered as good synthons for the synthesis of 2-thiopyrimidine derivatives [31]. It has been reported that substituted thiosemicarbazones 1a–e reacted with TCNE (2) in ethyl acetate with the for- mation of products 3 to 5 (Scheme 1) [32]. Also, according to the formation of 3–5, both the thioxosulfur and azomethine groups had taken part in heterocyclization [32]. Because aldehyde hydrazones are known to react as aza-enamines [33–35] toward suitable electrophiles, this behavior should consequently also be open to aldehyde thiosemicarbazones because the substituted thiocarbamoyl group is not a strong acceptor and may even be sterically hindered. Further, investigation of the reactivity of (1-aryl ethylidene)hydrazinecarbothioamides 6a–c toward (TCNE, 2) will be discussed in the present investigation. © 2015 HeteroCorporation