Synthesis of New C-C Linked Bichalcones and Their Antimicrobial and Antioxidant Activities

Bichalcones are obtained naturally from the genus Rhus. Bichalcones have attracted attention not only from a synthetic perspective but also because of their broad-spectrum biological activities. A series of methoxy-substituted chalcones (1–9) yielded C-C linked bichalcones (10–18) by the Ullmann coupling method, and their antimicrobial and antioxidant activities were assessed in this study. The confirmation of the synthesized compounds\u27 structures was performed by NMR (1H, 13C, APT, and COSY), FT-IR, UV, and HRESI-TOF-MS data. According to the preliminary results, a number of the said compounds exhibited an interesting activity against Candida tropicalis. Moreover, the antioxidant activities of bichalcones (10–18) were evaluated according to DPPH and FRAP methods. Concerning antioxidant activities, compounds 15 and 16 were the most active compared to Trolox used as a standard. Of all the synthesized new bichalcone derivatives, compounds 10, 11, 12, 14, and 17 displayed higher activity against to fungal microorganism Candida tropicalis. Compounds 15 and 16 were found to have the highest antioxidant activity according to both DPPH and FRAP methods

Minor saponins from the sea cucumber <i>Cucumaria frondosa </i>

399-404The structures of three saponins from Cucumaria frondosa have been determined principally by high field 1D and 2D NMR data. Frondoside F 5 is shown to possess the structure 3β-O-{3-O-methyl-6-sulfonato-β--glucopyranosyl(1→3)-O-β--6-sulfonato-glucopyranosyl-(1→4)- O-[β- -xylopyranosyl-(1→2))-O-β--quinovopyranosyl-(1→2)- O-β--4-sulfonato-xylopyranosyly} -17α-hydroxy-20R-acetoxy-22R-hydroxy-5α-lanost-24-ene-18-carboxylic acid (18-22) lactone, trisodium salt and represents a new class of holothurin distinguished by its C-18-22 lactone. Frondoside E2 7 is 3β-O-{3-O-methyl-β--glucopyranosyl(1→3)- O-β- -glucopyranosyl-(1→4)- O-[β--xylopyranosyl(1→2)]- O-β--quinovopyranosyl-(1→2)-O-β--4-sulfonatopyranosyl}-holosta-9(11),24-dien-16-one, sodium (or potassium) salt, while frondoside E1 6 is found to be identical with previously reported cucumarioside A2-2 from C. japonica.</i

Conventional and microwave-irradiated synthesis of new bischalcone derivatives

WOS: 000470072800002A series of 12 novel methyl- and halogen-substituted bischalcones containing an azo linkage was synthesized by a Claisen-Schmidt condensation between (E)-1-{4-[(4-acetyl-2-hydroxyphenyl)diazenyl]phenyl}ethanone and various araldehydes using microwave irradiation and conventional procedures and the results were compared.Karadeniz Technical University (BAP)Karadeniz Teknik University [2012/9181]The author(s) disclosed receipt of the following financial support for the research, authorship and/or publication of this article: This work received financial support from The Research Fund of Karadeniz Technical University (BAP, Project No. 2012/9181)

Synthesis, antibacterial and antioxidant activities of new 1-alkyl-4-(1-alkyl-4-oxo-1,4-dihydroquinolin-2-yl)pyridinium bromides

AKAR, ZEYNEP/0000-0001-9262-8070WOS: 000330603900033PubMed: 24077525New 1-alkyl-4-(1-alkyl-4-oxo-1,4-dihydroquinolin-2-yl)pyridinium bromides (3a k) were synthesized from 1,4'-diazaflavone [2-pyridin-4-ylquinolin-4(1H)-one] and evaluated for antibacterial and antioxidant activities. A rapid one-pot preparation of 1,4'-diazaflavone (2) was done from 2'-amino substituted chalcone (1) by intramolecular Michael addition using solvent-free microwave heating. New N,N'-dialkyl substituted (C-5-C-15) 1,4'-diazaflavonium bromides were synthesized from compound 2 with corresponding alkyl halides. Compounds 3a k were active against six bacteria (MIC: 7.8-500.0 mu g/mL). They also showed good antioxidant activities in DPPI-1* scavenging (SC50: 45-133 mu g/mL) and ferric reducing/antioxidant power (14-141 p.M TEAC) tests. the biological activities decreased as alkyl chain length increased. the reason behind the obvious negative effect of alkyl chain elongation is unclear and requires investigations about the intermolecular interactions of these pyridinium salts with bioassay components. (C) 2013 Elsevier Masson SAS. All rights reserved.Karadeniz Technical UniversityKaradeniz Technical University; Scientific and Technological Research Council of TurkeyTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [TUBiTAK-109T388]This study was supported by grants from Karadeniz Technical University and the Scientific and Technological Research Council of Turkey (TUBiTAK-109T388)