%0 Journal Article
%T Design and Synthesis of Novel Isoxazole Tethered Quinone-Amino Acid Hybrids
%A P. Ravi Kumar
%A Manoranjan Behera
%A M. Sambaiah
%A Venu Kandula
%A Nagaraju Payili
%A A. Jaya Shree
%A Satyanarayana Yennam
%J Journal of Amino Acids
%D 2014
%I Hindawi Publishing Corporation
%R 10.1155/2014/721291
%X A new series of isoxazole tethered quinone-amino acid hybrids has been designed and synthesized involving 1,3-dipolar cycloaddition reaction followed by an oxidation reaction using cerium ammonium nitrate (CAN). Using this method, for the first time various isoxazole tethered quinone-phenyl alanine and quinone-alanine hybrids were synthesized from simple commercially available 4-bromobenzyl bromide, propargyl bromide, and 2,5-dimethoxybenzaldehyde in good yield. 1. Introduction Compounds containing the quinone group present an important class of biologically active molecules that are widespread in nature [1¨C3]. The discoveries of antibiotic [4, 5] and antitumor [6] properties assigned to several natural quinones have raised interest among scientists for use as pharmaceuticals. While antibiotics display an enormous diversity in chemical structures, quinone antibiotics such as Adriamycin, Mitomycin C, and Streptonigrin deserve special attention [7¨C10]. In this context, search of new molecules containing quinone moiety has always fascinated the organic as well as medicinal chemist. Isoxazole derivatives are an important class of heterocyclic pharmaceuticals and bioactive natural products because of their significant and wide spectrum of biological activities, including potent and selective antagonism of the NMDA receptor and anti-HIV activity. [11, 12]. It shows antihyperglycemic [13], analgesic [14], anti-inflammatory [15], antifungal [16], and antibacterial activity [17]. 3,5-Disubstituted isoxazole derivatives which are biological active include muscimol, dihydromuscimol, micafungin, and cycloserine [18, 19]. Unnatural amino acids, the nonproteinogenic ¦Á-amino acids that occur either naturally or chemically synthesized, have been used widely as chiral building block. They have been also used as molecular scaffolds in constructing combinatorial libraries [20]. They represent a powerful tool in drug discovery when incorporated into therapeutic peptidomimetics and peptide analogs [21]. The seminal work on the synthesis of unnatural amino acids has been done by O¡¯Donnell and Maruoka independently, which accelerated the application of this class of amino acid for practical applications [22, 23]. Synthesis of hybrid natural products has gained momentum in recent years [24¨C26]. It is expected that combining features of more than one biologically active natural segment in a single molecule may result in pronounced pharmacological activity while retaining high diversity and biological relevance. There are a few reports describing the preparation of
%U http://www.hindawi.com/journals/jaa/2014/721291/