Abolghasem Moghimi
Department of Chemistry, Imam Hossein University, Tehran, I.R. IRAN
[ 1 ] - Microwave Assisted Selective Synthesis of four Chromanones Via Biscyclization Method in the Presence of Polyphosphoric Acid and Crystal Structure Determination of Their Dicarboxylic Acids
Microwave irradiation is used in the synthesis of four tricyclic chromanones 11-14. The chromanone 14 and 12 are selectively formed thermally and under microwave in the presence of polyphosphoric acid (PPA) from the same dicarboxylic acid 9, respectively. The crystal structures of the two diacids are also reported. The corresponding ortho and meta isomers of diacids crystallize in the space...
[ 2 ] - 2H Isotope Effect on 13C Chemical Shifts of Nitro-Benzo-9-Crown-3
Deuterium substitution on two ortho-substituted-OCH2-fragments in Nitro-Benzo-9-Crown-3 induces low frequency shifts, positive mnDCj, in all 13C NMR resonances which is an indication of the increased shielding in this crown ether. The magnitude of these shifts vary from 15DC7=716 to 54D<...
[ 3 ] - Influence of Metal Ion Complexation on the Acid Dissociation of 4'-Carboxybenzo-24-Crown-8 in an Ethanol-Water Mixture
A spectrophotometric method was used to determine the acidity constant of 4'-carboxybenzo-24-crown-8 in 52% (w/w) ethanol-water mixture. The acid dissociation constant, Ka, was found to increase in the presence of Na+, K+, Rb+, Cs+ and Tl+ ions. The formation constants of the resulting 1:1 complexes between the carboxycrown a...
نویسندگان همکار