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Xia, Likai,Magar, Krishna Bahadur Somai,Lee, Yong Rok ESCOM Science Publishers 2015 Molecular diversity Vol.19 No.1
<P>A new phosphine-catalyzed [3+2] annulation reaction between activated 1,4-naphthoquinones and acetylenecarboxylates is described. This reaction provides a facile and efficient route to a variety of biologically promising and novel naphtho[1,2-]furans. This devised method provides a first example for the synthesis of diverse naphtho[1,2-]furan derivatives from 1,4-naphthoquinones via phosphine-catalyzed [3+2] annulation. A variety of novel naphtho[1,2-]furans were synthesized via the phosphine-catalyzed [3+2] annulation of activated 1,4-naphthoquinones and electron-deficient acetylenecarboxylates. In some reactions, both furannulation adducts and reductive/nucleophilic conjugate addition products were produced.</P>
Kang, So Rang,Lee, Yong Rok ESCOM Science Publishers 2015 Molecular diversity Vol.19 No.2
<P>Efficient one-pot three-component reactions of pyrazolones with arylaldehydes and triethyl phosphite were carried out in the presence of ethylenediammonium diacetate as catalyst to synthesize biologically interesting pyrazolylphosphonate derivatives. This methodology offers several significant advantages such as environmentally benign character, the use of a mild catalyst, high yields, and ease of handling. The synthesized compounds were screened for their antioxidant and antibacterial activities. The result showed that compound 4d [Formula: see text] exhibited a strong free radical scavenger toward DPPH free radicals compared with standard BHT [Formula: see text]. In addition, compounds 4e and 4p showed potent antibacterial activities against Gram-negative bacteria of E. coli and compound 4o exhibited a potent activity against Gram-positive bacteria of S. aureus compared with standard Ampicillin.</P>
Efficient Cu(OTf)2-catalyzed synthesis of novel and diverse 2,3-dihydroquinazolin-4(1H)-ones.
Zhu, Xiaoyan,Kang, So Rang,Xia, Likai,Lee, Jihye,Basavegowda, Nagaraj,Lee, Yong Rok ESCOM Science Publishers 2015 Molecular diversity Vol.19 No.1
<P>An efficient one-pot synthesis of various 2,3-dihydroquinazolin-4(1H)-one derivatives was accomplished using Cu(OTf)2-catalyzed multi-component reactions between isatoic anhydride, ketones, and amines. The method has several significant advantages; mild reaction conditions, easy handling, and efficiency of catalyst.</P>
Harikishore, Amaravadhi,Li, Enlin,Lee, Jia Jun,Cho, Nam-Joon,Yoon, Ho Sup ESCOM Science Publishers 2015 Molecular diversity Vol.19 No.3
<P>Hepatitis C virus (HCV) infection or HCV-related liver diseases are now shown to cause more than 350,000 deaths every year. Adaptability of HCV genome to vary its composition and the existence of multiple strains makes it more difficult to combat the emergence of drug-resistant HCV infections. Among the HCV polyprotein which has both the structural and non-structural regions, the non-structural protein NS5B RNA-dependent RNA polymerase (RdRP) mainly mediates the catalytic role of RNA replication in conjunction with its viral protein machinery as well as host chaperone proteins. Lack of such RNA-dependent RNA polymerase enzyme in host had made it an attractive and hotly pursued target for drug discovery efforts. Recent drug discovery efforts targeting HCV RdRP have seen success with FDA approval for sofosbuvir as a direct-acting antiviral against HCV infection. However, variations in drug-binding sites induce drug resistance, and therefore targeting allosteric sites could delay the emergence of drug resistance. In this study, we focussed on allosteric thumb site II of the non-structural protein NS5B RNA-dependent RNA polymerase and developed a five-feature pharmacophore hypothesis/model which estimated the experimental activity with a strong correlation of 0.971 & 0.944 for training and test sets, respectively. Further, the G?ner-Henry score of 0.6 suggests that the model was able to discern the active and inactive compounds and enrich the true positives during a database search. In this study, database search and molecular docking results supported by experimental HCV viral replication inhibition assays suggested ligands with best fitness to the pharmacophore model dock to the key residues involved in thumbs site II, which inhibited the HCV 1b viral replication in sub-micro-molar range.</P>
Atar, Amol B,Jeong, Yeon Tae ESCOM Science Publishers 2014 Molecular diversity Vol.18 No.2
<P>A series of diverse polyfunctionalized triheterocyclic benzothiazoles were easily prepared in excellent yields via the Biginelli reaction of 2-aminobenzothiazole with substituted benzaldehydes and α-methylene ketones using FeF(3) as an expeditious catalyst under solvent-free conditions. The protocol provides a practical and straightforward approach toward highly functionalized triheterocyclic benzothiazole derivatives in excellent yields. The reaction was conveniently promoted by FeF(3) and the catalyst could be recovered easily after the reaction and reused without any loss of its catalytic activity. The advantageous features of this methodology are high atom economy, operational simplicity, shorter reaction time, convergence, and facile automation.</P>