%0 Journal Article
%T One-Pot Synthesis of Metallopyrazinoporphyrazines Using 2,3-Diaminomaleonitrile and 1,2-Dicarbonyl Compounds Accelerated by Microwave Irradiation
%A Ali Maleki
%A Ali Hossein Rezayan
%J Organic Chemistry International
%D 2014
%I Hindawi Publishing Corporation
%R 10.1155/2014/958951
%X A one-pot microwave-assisted synthesis of metallopyrazinoporphyrazines as porphyrazine derivatives carrying six-membered pyrazine rings annulated at the periphery of the tetrapyrrolic macrocycle is described starting from 2,3-diaminomaleonitrile, 1,2-dicarbonyl compounds, metal salts, and urea. 1. Introduction Tetrapyrrolic macrocycles of porphyrins, phthalocyanines, and related compounds, modified by the attachment of peripheral substituents, have attracted significant attention for many years because of their industrial applications in diverse areas, especially in modern technologies [1每4], such as elaboration of Langmuir-Blodgett films [5每7], chemical sensors [8, 9], nonlinear optical materials [10每12] biomedical agents for diagnosis, and therapy [13] as well as sensitizers in solar cells [14每16]. Porphyrazines (Pzs), as an important class of phthalocyanine analogues or porphyrinoid macrocycles, carrying heterocyclic rings, such as diazepine, pyridine, and pyrazine rings, directly annulated to the pyrrole rings of the porphyrazine core, have been presented in recent years as optical agents with clear advantages over the porphyrins [17每25]. Porphyrins are either naturally occurring molecular systems or original synthetic products, whereas Pzs are derived exclusively from synthetic laboratory work. An area of further expansion of new Pzs macrocycles can be directed to the synthesis of new phthalocyanines-like macrocycles opening a route to new forms of investigation and promising potential practical applications [26]. Metal complexes of Pzs (MPzs) ligands have been at the focus of interest because of their high electronic delocalization, biological significance, and numerous potential technological applications such as electronic, magnetic, photophysical, and photosensitizing properties of Pzs [27每31]. It has been found that functional groups fused to the peripheral positions of MPzs are integrated to the macrocyclic core more effectively than that of phthalocyanines [32每34]. It implies that the modification of the structure influences the photosensitizing properties [35]. There are only a few reports for the synthesis of Pzs under mild and efficient conditions. On the other hand, attempts for direct synthesis of Pzs carrying unprotected vicinal NH2 groups from 2,3-diaminomaleodinitrile were unsuccessful [17每20]. Due to the importance of these macrocycles, introduction of new, efficient, and inexpensive protocol for this purpose is of prime importance. Microwave-assisted organic reactions are well known as environmentally benign transformations that
%U http://www.hindawi.com/journals/oci/2014/958951/