Youssef Diab

Chemical Composition of Lebanese Rosemary (Rosmarinus officinalis L.) Essential Oil as a Function of the Geographical Region and the Harvest Time

Abstract The essential oils of rosemary (Rosmarinus officinalis L.) from three locations in Lebanon were extracted by steam distillation and their chemical composition was determined by GC/MS. The plants were collected during two years at either flowering stage or after. The oils obtained did not show appreciable differences in their composition in relation to geographical region. The three oil samples were found to be rich in α-pinene (18.8–38.5%) and 1,8-cineole (19.1–25.1%). The Lebanese oils had particularly high levels of α-terpineol (2.9–11.2%) and geraniol (1.8–9.3%). Although the results obtained did not indicate a large variation of oil composition in relation to harvest time (flowering and after flowering), some reproducible differences were noticeable. A parallel study on rosemary leaves and flowers from one of the three locations showed that their oils had the same chemical composition.

α-Phosphono-δ-lactones from γ-lactones via a rhodium(II)-catalysed Wolff rearrangement

Abstract e-Trimethylsilyloxy-α-diazo-β-ketophosphonates were prepared in two steps from γ-lactones. After exposure to catalytic rhodium(II) in refluxing toluene and further aqueous treatment, they gave rise to α-phosphono-δ-lactones in moderate to good yields.

Chemical Composition of the Essential Oil of Micromeria libanotica Boiss., an Endemic Species of Lebanon

Abstract The essential oil obtained by steam distillation from Micromeria libanotica growing wild in the cedar mountains of Lebanon, was examined by GC and GC/MS. Twenty-five components, representing about 83% of the oil were identified. The major constituents of the oil were found to be the monoterpene ketones isomenthone (44.5%), pulegone (13.5%) and isopulegone (6.5%).

2-Phosphonocyclopenten-2-ones from ε-tert-butyldimethylsilyloxy-α-diazo-β-ketophosphonates via a rhodium(II)-catalysed C–H insertion reaction

Abstract The exposure of certain primary e- tert -butyldimethylsilyloxy-α-diazo-β-ketophosphonates to the action of catalytic rhodium(II) in refluxing toluene leads to a C–H insertion followed by elimination of the silyloxy group to give 2-phosphonocyclopenten-2-ones in fairly good yields.

Addition d'amino-esters ou d'α-hydroxy-esters sur des azirines.

Abstract Addition of α-amino-esters or α-hydroxy-esters to azirines is studied. Two molecules of 2-methyl-3-phenyl 2H-azirine react with one molecule of α-hydroxy-ester ; a 1,3 dipolar addition is presumed.

Metal Carbonyl Compounds Entrapped Within Zeolite Cavities. Preparation, Characterization and Catalytic Properties.

Abstract Transition metal ions in zeolite show a distinct trend to coordinate CO. The stability of the carbonyl species strongly depended on the ability of transition metal ionsto transfer d electrons into the II* orbital of CO. The highly electrophilic character of the noble metal carbonyl carbon accounted for most of the chemical reactivity. Mononuclear monovalent dicarbonyls resulted from the reduction of high valent carbonyls via attack of an OH- group on the carbonyl carbon. The structure of monovalent carbonyls was determined using a combination of XPS, UV, IR, 13C NMR and volumetric methods. The nature of the bonding of the monovalent carbonyls was investigated and displacement of the lattice oxide ligands could occur using donor ligands. Further reduction of the monovalent carbonyls to tetra- and hexa-nuclear complexes was performed using H2O:CO or H2:CO mixtures. Again the structure was determined using IR and NMR studies supplemented by volumetric measurements. The catalytic activity of both types (mono- and poly-nuclear) of carbonyls was investigated in CO insertion reactions into organic substrates and in the water gas shift reaction.

Hemisynthesis, Antitumoral Effect, and Molecular Docking Studies of Ferutinin and Its Analogues.

The natural product ferutinin was shown to act as an agonist to estrogen receptor ERα and agonist/antagonist to ERβ featuring a weak antiproliferative activity toward breast cancer cells. To enhance this activity, ferutinin analogues were synthesized by esterification of jaeschkenadiol with different acids. These compounds were assayed for their in vitro antiproliferative activity against estrogen‐dependent (MCF‐7) and estrogen‐independent (MDA‐MB‐231) breast cancer cell lines. Among the compounds, 3c’ exhibited a potent inhibitory selective activity against MCF‐7 with IC50 value of 1 μm. Docking simulation of 3c’ in the ligand binding domain of the ERs indicated a potential antagonism interaction with both ER subtypes. Functional assay showed that 3c’ binds as an antagonist to ERα protein while ferutinin acts as an agonist.

Shape-selective synthesis of substituted pyridine on zeolite-hosted monovalent cobalt

The synthesis of diphenyl methyl pyridine via the cotrimerization of phenyl acetylene and acetonitrile using a novel monovalent cobalt catalyst generated reductively in zeolitic media is described.