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43 results on '"DAICH, ADAM"'

1. Autotandem Catalysis: Inexpensive and Green Access to Functionalized Ketones by Intermolecular Iron‐Catalyzed Amidoalkynylation/Hydration Cascade Reaction via N‐Acyliminium Ion Chemistry.

Author

Abdallahi, Sidi Mohamed, Ewies, Ewies F., El‐Shazly, Mohamed, Ould Elemine, Brahim, Hadou, Abderrahmane, Moncol, Ján, Lawson, Ata Martin, Daich, Adam, and Othman, Mohamed

Subjects
CATALYSIS, HYDRATION, CATALYSTS, IONS, KETONES, LEWIS acids
Abstract

Iron‐based catalysts were applied in cascade‐type reactions for the synthesis of different carbonyl compounds. The reactions proceeded by a new iron‐catalyzed cascade of alkynylation/hydration by using both the σ‐ and π‐Lewis acid properties of iron salts. The alkynylation reactions of several endo and exocyclic acetoxylactams were achieved with three different catalysts including FeCl3 ⋅ 6H2O, FeCl3, and Fe(OTf)3 showing the efficiency of σ‐Lewis acidity of iron (III) salts in catalyzing the alkynylation reaction. We also demonstrated that the reaction sequence could be shortened by the direct use of hydroxylactams, leading to an environmentally friendly protocol, avoiding the need to perform unnecessary lengthy steps. A combination of the hard/soft iron Lewis acid properties was then used to implement an unprecedented tandem intermolecular alkynylation/intramolecular hydration sequence allowing expedient access to a new carbonyl structures from trivial materials. [ABSTRACT FROM AUTHOR]

Published
2021
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2. Phytochemical and biological studies of Atriplex inflata f. Muell.: isolation of secondary bioactive metabolites.

Author

Ben Nejma, Aymen, Znati, Mansour, Nguir, Asma, Daich, Adam, Othman, Mohamed, Lawson, Ata Martin, and Ben Jannet, Hichem

Subjects
CHENOPODIACEAE, ATRIPLEX, METABOLITES, ARACHIDONIC acid, STAPHYLOCOCCUS aureus
Abstract

Objectives This work describes the phytochemical and biological investigation of the Tunisian Atriplex inflata F. Muell (Chenopodiaceae). Methods Their chemical structures were elucidated on the basis of extensive spectroscopic methods, including 1D NMR and 2D NMR, ESI- HRMS and comparison with available literature data. The isolates were evaluated for their antioxidant activity by the DPPH•, ABTS+•, Fe3+ and catalase assays and also for their antibacterial and anticholinesterase activity. Key findings The chemical study of Atriplex inflata F. Muell led to the isolation of two fatty acids (9 E)-methyl-8,11,12-trihydroxyoctadec-9-enoate 1 and (9 E)-8,11,12-trihydroxyoctadecenoic acid 2 together with ( Z)-litchiol B 3 and 20-hydroxyecdysone 4. Three of which are reported here for the first time in Atriplex genus. Based on the biosynthesis of hydroxylated arachidonic acid and derivatives, a plausible biogenesis pathway of the two fatty acids ( 1 and 2) was proposed. (Z)-litchiol B ( 3) was found to be the most active against Staphylococcus aureus. According to the literature, this is the first time that compounds 1, 2 and 3 were tested for their eventual biological activity. Conclusions In the results of the present work, we have proposed the biogenesis pathway of unsaturated fatty acid and described the structure-activity relationship. [ABSTRACT FROM AUTHOR]

Published
2017
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