These experiments showed that the hollow spheres

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Unformatted text preview: [email protected] Juglone (1) or 5-hydroxy-1,4-naphthoquinone is a simple two-ring naphthoquinone which consists of a phenolic and quinonic ring fused together. The antimicrobial activities of juglone (5 -hydroxy-1,4naphthoquinone) has been well studied and reported. Recently, the 7 -methyl natural derivative of juglone, 7-methyljuglone (2) has been identified as the bioactive compound in Euclea natalensis; a South African plant used in the folkloric treatment of chest complications. The antibacterial activities of some known and new synthetic juglone derivatives against both gram-positive and gram-negative bacteria are presented here. O H 3C O OH O OH O (1) (2) 189 23rd-25th June 2010 3rd ICYC 2010 Universiti Sains Malaysia ORG-O10 SYNTHESIS AND MESOMORPHIC PROPERTIES OF SCHIFF BASE ESTERS 4-NALKANOYLOXYBENZYLIDENE-4-IODOANILINES 1, *Sie-Tiong Ha, Teck-Leong Lee, Kok-Leei Foo, Guan-Yeow Yeap and Peng-Lim Boey 2 2 3 3 1 Faculty of Science, Universiti Tunku Abdul Rahman, Jalan Universiti Bandar Barat, 31900 Kampar, Perak, Malaysia 2 Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jln Genting Klang, Setapak, 53300 Kuala Lumpur, Malaysia 3 Liquid Crystal Research Laboratory, School of Chemical Sciences, Universiti Sains Malaysia, 11800 Minden, Pulau Pinang, Malaysia E-mail: [email protected] A new homologous series of Schiff base esters, 4-n-alkanoyloxybenzylidene-4-iodoanilines (nABIA) possessing even number of carbons (n) at the terminal ester chain have been synthesized and their molecular structures were postulated using elemental analysis and spectroscopic techniques including 1 13 FT-IR, H NMR and C NMR and EI-MS. Phase transition temperatures and associated enthalpy changes were determined using differential scanning calorimetry. The liquid crystals textures were observed under polarized optical microscope attached with a Mettler hotstage. Compounds nABIA (where n= 6, 8, 10, 12, 14, 16, 18) exhibited enantiotropic smectic A phases with fan -shaped textures, while 4ABIA is a non-mesogenic compound. The present series were compared with other structurally related compounds to study the structure-liquid crystal property relationship. N Cn-1H2n-1 COO I nABIA where n= 4, 6, 8...
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This note was uploaded on 02/17/2011 for the course CHEMISTRY 101 taught by Professor Csr during the Spring '11 term at University of Louisville.

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