Browsing by Author "Hammadi, Mohamed"
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Item Activated zeolites and heteropolyacids : an efficient catalysts for the synthesis of triacetoxyaromatic precursors of hydroxyquinones(2013) Dokari, Hadjila; Hammadi, MohamedItem Application of microwave heating of dry organic reactions : new condensation products from triacetic acid lactone (TAL)(2016) Benferrah, Nassima; Hammadi, Mohamed; Berthiol, FlorianThe work undertaken resides in the development of new methods of synthesis respectful of the environment. A convenient synthesis of bis(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl) arylmethanes are obtained by condensation of triacetic acid lactone (4-hydroxy-6methyl-2H-pyran-2-one) with aromatic aldehydes, in absence of the catalyst, without solvent by activation under microwave irradiation. This method has environmentally friendly advantages, short reaction time, high yields and easy preparation. We report here the synthesis of new heterocyclic compounds (dilactones) from TAL providing evidence for the particular reactivity of the position 3 of these compoundsItem Copper(II) complex of a Schiff base of dehydroacetic acid: Characterization and aerobic oxidation of benzyl alcohol(Elsevier, 2016) Benferrah, Nassima; Hammadi, Mohamed; Philouze, Christian; Berthiol, FlorianItem An easy synthesis of thermochromic ethylenes under microwave irradiation(2003) Villemin, Didier; Hachemi, Messaoud; Hammadi, MohamedThermochromic ethylenes were obtained by the reaction of anthrone with tricyclic ketones or terephthaldehyde in DMF in the presence of potassium ter-butoxide under reflux (8h) or under microwave irradiation (10 min.)Item Regioselective and Catalyst-Free Epoxidation of (E)-3-[3-(2-Hydroxyaryl)-3-oxoprop-1-en-1-yl]chromones(Georg Thieme Verlag, 2018) Ameraoui, Rachid; Hammadi, Mohamed; Talhi, Oualid; Hassaine, Ridha; Bouchama, Abdelghani; Abdeldjebar, Hasnia; Belmiloud, Yamina; Brahimi, Meziane; Almeida Paz, Filipe A.; Bachari, Khaldoun; Silva, Artur M. S.The uncatalyzed reaction of hydrogen peroxide with (E)-3-[3-(2-hydroxyaryl)-3-oxoprop-1-en-1-yl]chromones resulted in a regioselective epoxidation of the chromone intracyclic C(2)=C(3) double bond to afford unique isomeric (E)-7a-[3-(2-hydroxyphenyl)-3-oxoprop-1-en-1-yl]-1aH-oxireno[2,3-b]chromen-7(7aH)-ones in high yields. 2D NMR and single-crystal X-ray diffraction were used to elucidate the structures of the chromanone epoxides. Density functional theoretical studies demonstrated a high electrophilicity of the starting chromonesItem Tungstosilicic acid (H4SiW12O40) have efficient catalysts for synthesis of 2,3-Dihydroxynaphthoquinone from lawsone(2016) Benferrah, Nassima; Hammadi, Mohamed; Dokari, Hadjila; Villemin, DidierThe Thiele–Winter reaction is of interest for synthesis of tetracetoxyaromatic precursors of hydroxynaphtoquinones. Solid acids such as Tungstosilicic acid (H4 SiW12O40) have an efficient catalyst in acetoxylation reaction of naphtoquinones without the use of organic solvent at room temperature. 1,2,3,4-Tetrahydroxynaphthalene was easily oxidized at room temperature in 2,3-Dihydroxynaphthoquinone by using (Pc[Co]/K10) and air (1 atm). We have also tested this type of reaction in 2-hydroxynaphthoquinone (Lawsone). Many naphthoquinones are natural products with interesting biological properties