Moncef Msaddek

1,5-Benzodiazepin-2-ones: Investigation of a Family of Photoluminescent Materials

Photoluminescent materials, that are now ubiquitous in our everyday life, have particularly attracted the attention of the scientific community these past few years due to potential important applications such as in bioimaging, sensing, or optoelectronics. In this context, relatively few different families of molecules have been reported to exhibit fluorescence in the aggregated or solid-state through the excited-state intramolecular proton transfer (ESIPT) photochemical process. The preparation and subsequent determination of photochemical properties of an underexplored family of 1,5-benzodiazepin-2-one derivatives are reported. From these data and X-ray diffraction analysis study, it emerged that photoluminescence (in the range 520-655 nm) was mostly attributed to ESIPT. The photoluminescent potential of 1,5-benzodiazepin-2-ones, their facile access, and functionalization were demonstrated through the preparation of two fluorogenic probes for the selective detection of biothiols.

Copper Nanoparticles Cycloaddition of Terminal Acetylenes with Carbohydrate Azide

Abstract Copper nanoparticles have been found to effectively catalyse the asymmetric synthesis of 1,2,3-triazoles from cycloaddition of carbohydrate azide and terminal acetylenes in water. In all case the cycloaddition is accomplished with complete regioselectivity.Graphical Abstract

Chemoselectivity of the 1,3-dipolar cycloaddition of some diazoalkanes with 1,5-benzodiazepine derivatives

Benzodiazepines are pharmaceutically important synthetic materials. Reaction of the 4-(2-hydroxyphenyl)-1,5-benzodiazepin-2-one with 2-diazopropane (DAP) gave a mixture of the 2-isopropylether of 4-(2-hydroxyphenyl)-3H-1,5-benzodiazepine and 1-isopropyl-4-(2-hydroxyphenyl)-3H-1,5-benzodiazepin-2-one. Whilst diphenyldiazomethane (DPDM) gave 1-benzhydryl-4-(2-hydroxyphenyl)-3H-1,5-benzodiazepin-2-one. Reaction of the corresponding thione with DAP led to the 2-isopropylthioether of 4-(2-hydroxyphenyl)-3H-1,5-benzodiazepine and 1-isopropyl-4-(2-hydroxyphenyl)-1,5-benzodiazepine-2-thione while the reaction with DPDM gave the 2-benzhydrylthioether of 4-(2-hydroxyphenyl)-3H-1,5-benzodiazepine. The characterisation of these prepared -N, -O and -S alkylated benzodiazepines involved 1D and 2D-NMR techniques, mass spectrometry and elemental analysis.

Stereoselective synthesis of enantiopure N-substituted pyrrolidin-2,5-dione derivatives by 1,3-dipolar cycloaddition and assessment of their in vitro antioxidant and antibacterial activities

1,3-Dipolar cycloaddition between a chiral nitrone and N-substituted maleimides afforded unprecedented enantiopure spiro-fused heterocycles in good yields with a high enantio- and diastereoselectivity. The reaction was taking place on the less hindered face of the nitrone. The obtaining heterocycles were screened for their in vitro antioxidant properties and the results revealed that the potent antioxidant activity was generally recorded to compounds (3g) and (3e). The in vitro antibacterial activities of these two compounds were also investigated and the results demonstrated the strongest potential of compound (3g) against all the tested bacteria. Molecular properties were analyzed and showed good oral drug candidate like properties and that could be exploited as a potential antioxidant and antimicrobial agent. Finally, the preliminary results obtained from this investigation attempted to clarify if the structurally different side chains of active compounds interfere with their biological properties.

Unprecedented stereoselective synthesis of 3-methylisoxazolidine-5-aryl-1,2,4-oxadiazoles via 1,3-dipolar cycloaddition and study of their in vitro antioxidant activity

ABSTRACT The stereoselective 1,3-dipolar cycloaddition between allyl cyanide and a menthone-derived nitrone led to the desired isoxazolidine in good yield. Once the nitrile group transformed to an amidoxime group, the cyclocondensation of various aldehydes with chiral amidoxime led to unprecedented enantiopure 3-methylisoxazolidine-5-aryl-1,2,4-oxadiazoles. The menthone chiral auxiliary was then removed with acid hydrolysis. The new compounds were also screened for their in vitro antioxidant activity using DPPH and FRAP assays. Some of the compounds showed promising antioxidant activity. GRAPHICAL ABSTRACT

Solution and solid-state fluorescence of 2-(2′-hydroxyphenyl)-1,5-benzodiazepin-2-one (HBD) borate complexes

A new family of fluorescent 1,5-benzodiazepin-2-one (HBD) borate complexes was prepared in good yields, and fully characterized by means of MS, NMR and IR spectroscopy, as well as X-ray crystal structure analysis for compound 13. Unlike their uncomplexed congeners, most of these cyclic boranils were emissive both in solution and the solid state, with maxima in the range of 426–596 nm. A systematic study of substituent effects revealed that the presence of a halogen atom specifically at position 8 of the fused-aromatic ring system led to an increase in fluorescence intensity in solution while electron rich substituents tended to extinguish the photoluminescence. Finally, a proof-of-concept study highlighted that the amide moiety of the benzodiazepinone framework could be functionalized with a chemical handle useful for subsequent specific modifications.

Reaction of 2‐Benzoyl‐1,2‐dihydroisoquinoline‐1‐carbonitrile Tetrafluoroborate with (Z)‐2‐Arylidene‐3(2H)‐benzofuranones – Access to Chromenopyrrole Derivatives

Spiro[pyrrole-3,2′-3(2H)-benzofuranones] 7 have been synthesized by [4+2] cycloaddition of 2-arylidene-3(2H)-benzofuranones with the 2-benzoyl-1,2-dihydroisoquinoline-1-carbonitrile tetrafluoroborates. In acidic medium or in refluxing DMF, the spiro compounds yield tetrasubstituted pyrroles or compounds derived from chromenopyrroles. The regio- and stereochemistry of the reaction was established by spectroscopic or X-ray analysis.

Crystal structure of (1S,2S,2′R,3a′S,5R)-2′-[(5-bromo-1H-indol-3-yl)meth­yl]-2-isopropyl-5,5′-dimethyl­dihydro-2′H-spiro­[cyclo­hexane-1,6′-imidazo[1,5-b]isoxazol]-4′(5′H)-one

The absolute structure for the title compound, which has five chiral centres has been determined in this analysis. The supramolecular architecture comprises parallel zigzag chains formed through N—H⋯N and C—H⋯O hydrogen bonds, as well as intramolecular C—H⋯O, C—H⋯N and C—H⋯π interactions.

Chemo- and Regioselective 1,3-Dipolar Cycloaddition of 2-Diazopropane over 1,4-Benzoquinone: Synthesis of New Pyrazoloquinones

Abstract 1,3-Dipolar cycloaddition reaction of 2-diazopropane 1 with 1,4-benzoquinone 2 carried out at −20 °C led to a minor mono-cycloadduct 4 and mixture of bis-cycloadducts 6 and 7. The same addition realized with 3H-pyrazole 7 at −60 °C for 2 h yields a mixture of compounds 8 and 9 and results in O-alkylation. The reaction of 3H-pyrazoles 4 and 7 with dimethylsulfoxide and oxalyl chloride under Swern conditions led to pyrazolenines 11 and 12. GRAPHICAL ABSTRACT

Synthesis of new pyrazolines and their biological evaluation as antimicrobial agents

2-Diazopropane and diazo compounds derived from aromatic aldehydes were reacted with aromatic esters of 3-hydroxyprop-1-yne to give the aromatic esters of 5-hydroxymethyl-3-substituted pyrazoles. Anti-microbial screening using the Gram positive (Staphylococcus aureus and Enterococcus fecalis) and Gram negative (Escherichia coli and Klebsiella pneumoniae) bacteria and the yeast Candida albicans, showed that these compounds had promising activity against both Gram positive and Gram negative bacteria.