Yassine Riadi

New eco-friendly animal bone meal catalysts for preparation of chalcones and aza-Michael adducts

Two efficient reactions were successfully carried out using Animal Bone Meal (ABM) and potassium fluoride or sodium nitrate doped ABMs as new heterogeneous catalysts under very mild conditions. After preparation and characterization of the catalysts, we first report their use in a simple and convenient synthesis of various chalcones by Claisen–Schmidt condensation and then in an aza-Michael addition involving several synthesized chalcones with aromatic amines. All the reactions were carried out at room temperature in methanol; the chalcone synthesis was also achieved in water environment under microwave irradiation. Doping ABM enhances the rate and yield at each reaction. Catalytic activities are discussed and the ability to re-use the ABM is demonstrated.ResultsFor Claisen–Schmidt the use of ABM alone, yields never exceeded 17%. In each entry, KF/ABM and NaNO3/ABM (79-97%) gave higher yields than using ABM alone under thermic condition. Also the reaction proceeded under microwave irradiation in good yields (72-94% for KF/ABM and 81-97% for NaNO3/ABM) and high purity. For aza-Michael addition the use of ABM doped with KF or NaNO3 increased the catalytic activity remarkably. The very high yields could be noted (84-95% for KF/ABM and 81-94% for NaNO3/ABM).ConclusionThe present method is an efficient and selective procedure for the synthesis of chalcones an aza-Michael adducts. The ABM and doped ABMs are a new, inexpensive and attractive solid supports which can contribute to the development of catalytic processes and reduced environmental problems.

Photochemical route for the synthesis of novel 2-monosubstituted pyrido[2,3-d]pyrimidines by palladium-catalyzed cross-coupling reactions

A novel and effective route for the synthesis of 2-monosubstituted pyrido[2,3-d]pyrimidines is reported starting from the corresponding 2-halogeno- and 2-methylsulfanyl-pyrido[2,3-d]pyrimidine through a palladium-catalyzed cross-coupling has been described. The reaction involved original halogen discrimination under visible light as an alternative source of energy. Alternatively, monoarylated compounds were elaborated from 2-halogeno pyrido[2,3-d]pyrimidine by C2 chlorine further displacement and from 2-methylsulfanyl-pyrido[2,3-d]pyrimidine by C-alkylsulfanyl release. We have described the first synthesis of mono substituted pyrido[2,3-d]pyrimidine series using a two strategies using visible light as a powerful synthetic tool for the preparation of focused libraries of biologically active compounds. The use of available starting materials, easy reaction conditions and catalytic processes combined with high yields of products are the main outcome of this method.Graphical abstract

Novel animal-bone-meal-supported palladium as a green and efficient catalyst for Suzuki coupling reaction in water, under sunlight

ABSTRACT Animal-bone-meal-supported palladium (0) was prepared and used as catalyst in the Suzuki coupling reaction in water, under sunlight as an alternative source of energy. This palladium has showed a high catalytic activity than tetrakis(triphenylphosphine) palladium (Pd(PPh3)4) in the Suzuki cross-coupling reaction (the reaction of 4-halogenopyridopyrimidine with boronic acids) in water via sunlight as the light source, with no addition of ligands. This green method affords heteroaryls with excellent yields in comparison with the classical method using tetrakis(triphenylphosphine) palladium. The green catalyst did not show any significant loss of activity, even when used up to five times. GRAPHICAL ABSTRACT

Ultrasound-assisted extraction of some branded tea: Optimization based on polyphenol content, antioxidant potential and thermodynamic study

Tea is one of the top beverages used around the world every day, which contains a high amount of polyphenols and antioxidants. The main aim of this research is to quantify some marketed black tea (Rabea, Lipton, Alkbous, Green gold and Haritham) for phenolic contents and antioxidant potential evaluation by ultrasound solvent extraction and was compared with conventional extraction. Ultrasonic extraction was optimized by considering frequencies (26 kHz, 40 kHz), temperature (30, 40 and 50 °C), and power (30, 40 and 50%) at a fixed time of 30 min. In both the ultrasonic frequencies, 40 °C temperature and 40% power combination exhibited highest cumulative yield (mg/100 g DW), total phenolic content (mg gallic acid/g DW), flavonoids (mg/g DW) and DPPH radical scavenging activity (%) in all branded tea. Within each brand of tea, at any temperature-power combination at particular frequency results were not significantly different. But, at a similar condition of temperature power results were found significantly different between two frequencies. Furthermore, ultrasonic extraction process was analyzed thermodynamically by selecting some basic parameters. Thermodynamics results showed the extraction process was feasible, spontaneous and irreversible. Also, 26 kHz ultrasonic probe is more appropriate for the extraction purpose and thermodynamically more acceptable as compared to 40 kHz ultrasonic bath. Moreover, Haritham was selected as the best tea brand due to its high polyphenol contents and antioxidant potential.

Synthesis and biological potentials of some new 1,3,4-oxadiazole analogues

In continuation of our research to explore new antiproliferative agents, we report herein the synthesis and antiproliferative activity of two new series of N-(substituted phenyl)-5-aryl-1,3,4-oxadiazol-2-amine (4a–j) and N-{[5-aryl-1,3,4-oxadiazol-2-yl]methyl}-substituted aniline (4k–t) analogs. The antiproliferative activity of fifteen compounds (4a–h, and 4n) was tested against nine different panels of nearly 60 NCI human cancer cell lines. N-(2-Methoxyphenyl)-5-(4-chlorophenyl)-1,3,4-oxadiazol-2-amine (4b) and 4-{5-[(2-Methoxyphenyl)amino]-1,3,4-oxadiazol-2-yl}phenol (4c) showed maximum antiproliferative activity among the series with a mean growth percents (GPs) of 45.20 and 56.73, respectively. The compound 4b showed significant percent growth inhibitions (GIs) on nearly 47 cancer cell lines and were found to have higher sensitivity towards HL-60(TB), MDA-MB-435, OVCAR-3, and K-562 with percent GIs (GIs) of 109.62, 105.90, 91.94, and 88.30, respectively. Similarly the compound, 4c showed significant percent GIs on nearly 42 cancer cell lines and were found to have higher sensitivity towards UO-31, MDA-MB-435, KM12, and K-562 with %GIs of 84.31, 80.52, 78.65, and 77.06, respectively. Both the compounds 4b and 4c showed better antiproliferative activity than the standard drug Imatinib while the antiproliferative activity of compound 4b was found to be nearly comparable to the standard drug 5-flurouracil (5-FU). The antiproliferative activity of five compounds (4o-s) was tested against the breast cancer cell lines (MCF-7 and MDA-MB-231) as per Sulforhodamine B assay (SRB assay). N-{[5-(4-Methoxyphenyl)-1,3,4-oxadiazol-2-yl]methyl}-4-methylaniline (4p) was found to have significant antiproliferative activity against MCF-7 and MDA-MB-231 with GI50 of 12.9 and 59.3 µM, respectively. Further, the free radical scavenging activity results were significant for the most active compounds, 4b (IC50 = 21.07 µM) and 4c (IC50 = 15.58 µM). The docking studies was also carried against tubulin enzyme and the most active compound (4b) showed good interaction with the residues Lys254, Ala250, Cys241, Val318, Ala316, Asn258, and Lys352 present in the hydrophobic cavity of tubulin.

Water-mediated synthesis of disubstituted 5-aminopyrimidines from vinyl azides under microwave irradiation

ABSTRACT An efficient and ecofriendly method for the synthesis of disubstituted 5-aminopyrimidines from vinyl azides and urea or thiourea was developed. This reaction proceeds under microwave irradiation conditions in the presence of water as a solvent. The remarkable features of this new protocol are high conversion, short reaction times, cleaner reaction profiles and straightforward procedure. GRAPHICAL ABSTRACT

A simple and eco-friendly microwave mediated route the synthesis of novel antimicrobial substituted quinoline-2-thiones

ABSTRACT An eco-friendly and efficient method was developed for the preparation of a new series of sulfur-containing quinolinthiones. Compounds 6a–o were synthesized from 4-methyl-2-thiocoumarin and arylhydrazides using water as a solvent under microwave irradiation. Some noteworthy features of our novel method are its cleanliness, short reaction time and high conversion rate, and the reaction proceeds (profiles) using a simple procedure. All of the prepared compounds were screened for their antibacterial efficacy in vitro using the disc diffusion method against bacterial strains. Compound (6j) showed the greatest potency with a 16 and 19 mm inhibition zone against Klebsiella pneumonia and Staphylococcus aureus, respectively. GRAPHICAL ABSTRACT