Synthesis of 1,3,4-Oxadiazoles by Iodine-mediated Oxidative Cyclization of Methyl Ketones with 4-Phenylsemicarbazide

An efficient one-pot method to access 5-amino-2-benzoyl-1,3,4-oxadiazoles via I2/DMSO promoted oxidative cyclization of 4-phenylsemicarbazide with (het)aryl methyl ketones under mild conditions was developed. This reaction proceeds smoothly with a wide range of methyl ketones containing different functional groups to give the corresponding products in moderate yields under mild conditions.

One-pot synthesis and biological evaluation of novel 3-(5-((aryl) methyl) isoxazol-3-yl)-4H-chromen-4-one derivatives as potent antibacterial and anticancer agents

In search of better antibacterial and anticancer agents, a series of novel 3-(5-((aryl) methyl) isoxazol-3-yl)-4Hchromen- 4-one derivatives was synthesized (4a-4l) by using 4-oxo-4H-chromene-3-carbaldehyde and alkyne via in situ generated nitrile oxide and evaluated for their antibacterial and anticancer activity in vitro. Antibacterial activity was evaluated against three G+ bacterial strains and anticancer activity against breast cancer cell line (MCF-7) and cervical carcinoma cell line (HeLa). Among all the tested compounds, 4j and 4g exhibited potent antibacterial activity against tested grampositive bacterial strains. 4g, 4i and 4j exhibited potent cytotoxic activity against MCF-7 with IC50 values nearer to the standard drug doxorubicin.

High chemoselectivity to the construction of aryl methyl sulfones via an unexpected C-S bond formation between sulfonylhydrazides and dimethyl phosphite

In this research, a high chemoselectivity to access aryl methyl sulfones via an unexpected C-S bond formation between sulfonylhydrazides and dimethyl phosphite catalyzed by NaI under mild conditions was established. This transformation provides an alternative and metal-free path way to acquire various aryl methyl sulfones in good to excellent yields. Notably, dimethyl phosphite was employed as a type of stable and readily available alkyl source.

One-pot synthesis of 1-(benzothiazolylamino)aryl methyl-2-naphthols and 3-benzothiazolyl 2,3-dihydroquinazolinones using a magnetically recoverable core–shell nanocomposite as catalyst

Nano-magnetite-supported sulfated polyethylene glycol (Fe3O4@PEG-SO3H) was prepared, characterized and utilized as a magnetically recoverable heterogeneous catalyst for the one-pot, three-component reaction of 2-aminobenzothiazole, aldehydes and 2-naphthol/isatoic anhydride resulting in efficient formation of 1-(benzothiazolylamino)arylmethyl-2-naphthol or dihydroquinazolinones derivatives. The significant features of this method include green conditions, operational simplicity, minimizing production of chemical waste, shorter reaction times and good to high yields. In addition, the nanocatalyst can easily be separated from the reaction mixture by application of a magnetic field and reused without significant deterioration in its catalytic activity.

Alumination of Aryl Methyl Ethers: Switching Between Sp2 and Sp3 C–O Bond Functionalisation with Pd-Catalysis

The reaction of [{(ArNCMe)2CH}Al] (Ar = 2,6-di-iso-propylphenyl, 1) with aryl methyl ethers proceeded with alumination of the sp3 C–O bond by a presumed SN2 pathway. The selectivity of this reaction could be switched by inclusion of a catalyst. In the presence of [Pd(PCy3)2], chemoselective sp2 C–O bond functionalisation was observed. Kinetic isotope experiments and DFT calculations support a catalytic pathway involving the ligand-assisted oxidative addition of the sp2 C–O bond to a Pd---Al intermetallic complex. The net result of both non-catalysed and catalytic pathways is the generation of polar organoaluminium complexes from aryl methyl ethers with complete atom-efficiency. Switches in selectivity yield isomeric products from a single starting material. The methodology (and mechanistic insight) holds promise as a means to functionalise aromatic molecules derived from lignin depolymerisation and we demonstrate an application to a derivative of vanillin.

Alumination of Aryl Methyl Ethers: Switching Between Sp2 and Sp3 C–O Bond Functionalisation with Pd-Catalysis

The reaction of [{(ArNCMe)2CH}Al] (Ar = 2,6-di-iso-propylphenyl, 1) with aryl methyl ethers proceeded with alumination of the sp3 C–O bond by a presumed SN2 pathway. The selectivity of this reaction could be switched by inclusion of a catalyst. In the presence of [Pd(PCy3)2], chemoselective sp2 C–O bond functionalisation was observed. Kinetic isotope experiments and DFT calculations support a catalytic pathway involving the ligand-assisted oxidative addition of the sp2 C–O bond to a Pd---Al intermetallic complex. The net result of both non-catalysed and catalytic pathways is the generation of polar organoaluminium complexes from aryl methyl ethers with complete atom-efficiency. Switches in selectivity yield isomeric products from a single starting material. The methodology (and mechanistic insight) holds promise as a means to functionalise aromatic molecules derived from lignin depolymerisation and we demonstrate an application to a derivative of vanillin.