Cobalt-Catalyzed Chemoselective Reduction of N-Heteroaryl Ketones with N,N-Dimethylformamide as a Hydride Source.

A method for chemoselective reduction of 2-pyridyl ketones and related N-heteroaryl compounds catalyzed by cobalt stearate using DMF as a hydride source is developed. The ketone substrate is activated by chelation with cobalt, which makes the present method highly chemoselective. A possible reaction mechanism is proposed on the basis of control experiments.

Reductive Hydrodehalogenation of Halogenated Carboxylic Acid Derivatives Using a DMSO/HCOONa·2H2O System.

A practical and operationally simple hydrodehalogenation of halogenated carboxylic acid derivatives using a DMSO/HCOONa·2H2O system is developed. This protocol avoids the involvement of light irradiation, electrochemical apparatus, transition metals, radical initiators, strong bases, and other additional additives. Control experiments suggest that HCOONa might function as a hydride donor in the reduction process via nucleophilic substitution or addition to achieve the hydrodehalogenation.

A Mechanistic Study for Aziridination of Nitroalkenes Mediated by N-Chlorosuccinimide.

Direct aziridination of a nitrostyrene is achieved upon treatment with an alkylamine and N-chlorosuccinimide. The reaction is initiated by the Michael addition of amine to nitroalkene. Subsequent N-chlorination and nucleophilic substitution at the nitrogen atom afford 1-alkyl-2-nitroaziridine diastereoselectively. This reaction mechanism was clarified by NMR studies.

Recent Progress in Nitro-Promoted Direct Functionalization of Pyridones and Quinolones.

Nitro group is one of the most important functional groups in organic syntheses because its strongly electron-withdrawing ability activates the scaffold, facilitating the reaction with nucleophilic reagents or the Diels-Alder reaction. In this review, recent progress in the nitro-promoted direct functionalization of pyridones and quinolones is highlighted to complement previous reviews.

Ru-Catalyzed Selective C(sp3 )-H Monoborylation of Amides and Esters.

A ruthenium-catalyzed method has been developed for the C(sp3 )-H monoborylation of various unactivated alkyl and aryl amides and challenging esters, with a low-cost and bench-stable boron source, providing boronates with exclusive selectivity, high efficiency, and high turnover number (up to 8900). This novel strategy may offer a versatile and environmentally friendly alternative to current methods for selective C(sp3 )-H borylation that employ even more expensive metals, such as iridium and rhodium.

Environmentally Benign, Base-Promoted Selective Amination of Polyhalogenated Pyridines.

An environmentally benign, highly efficient, and base-promoted selective amination of various polyhalogenated pyridines including the challenging pyridine chlorides to 2-aminopyridine derivatives using water as solvent has been developed. Featuring the use of the new method, the reaction is extended to the transformation on a large scale. Mechanistic studies indicate that the pathway involving a base aidant dissociation of N,N-dimethylformamide to generate dimethylamine is likely.

Direct dihalo-alkoxylation of nitroalkenes leading to ß,ß-dihalo-ß-nitroethyl alkyl ethers.

A highly efficient one-pot synthesis of ß,ß-dihalo-ß-nitroethyl alkyl ethers is achieved by the treatment of nitroalkenes with alcohols and N-halosuccinimides in the presence of sodium hydride. The notable advantages of this protocol are that it involves simple experimental manipulations and tolerates a wide range of functional groups. Further transformations of the obtained ethers, such as allylation and conversion to ß,ß-dihalogenated vinyl ethers, are also investigated.

Direct Aziridination of Nitroalkenes Affording N-Alkyl-C-nitroaziridines and the Subsequent Lewis Acid Mediated Isomerization to ß-Nitroenamines.

A mild and highly diastereoselective one-pot synthesis of trans-N-alkyl-C-nitroaziridines was achieved by treatment of nitroalkenes with aliphatic amines and N-chlorosuccinimide. Treatment of the obtained aziridines with a Lewis acid resulted in a facile ring opening reaction, accompanied by rearrangement and isomerization into functionalized (Z)-ß-nitroenamines.

A direct and vicinal functionalization of the 1-methyl-2-quinolone framework: 4-alkoxylation and 3-chlorination.

Bis(functionalization), 4-alkoxylation and 3-chlorination, of the 1-methyl-2-quinolone framework was achieved under mild conditions by a sequential treatment of 3-nitrated 1-methyl-2-quinolones with sodium alkoxide and N-chlorosuccinimide. Moreover, a succinimide group instead of an alkoxy group was introduced at the 4-position, affording a masked form of the 4-amino-3-chloro-2-quinolone derivative. Furthermore, the prepared vicinally functionalized quinolones thus obtained were subjected to a Suzuki-Miyaura coupling reaction, arylating the 3-position.

2-(2-Methylfuran-3-carboxamido)-3-phenylpropanoic acid, a potential CYP26A1 inhibitor to enhance all-trans retinoic acid-induced leukemia cell differentiation based on virtual screening and biological evaluation.

To develop new CYP26A1 inhibitors, a three-cycle virtual screening was carried out based on the constructed homology model of human CYP26A1 using Dock, Fred, Gold and AutoDock. Twenty-two compounds exhibited high scores and reasonable binding modes in molecular docking were purchased from Specs Company. Eighteen compounds were tested their abilities to enhance ATRA-induced differentiation in human acute promyelocytic leukemia NB4 cells. Eight of them enhanced the ability of ATRA to induce differentiation at concentrations of 0.5 and 1 µM. Among these compounds, 2-(2-methylfuran-3-carboxamido)-3-phenylpropanoic acid (S8) is of most effective in blocking ATRA breaking down in NB4 cells based on the LC-MS/MS assay.

Synthesis and biological evaluation of (--)-linarinic acid derivatives as neuroprotective agents against OGD-induced cell damage.

A series of novel (-)-1,2,3,9-tetrahydropyrrolo[2,1-b]quinazoline-1-carboxylic acid derivatives were designed and synthesized. All of the prepared compounds were screened for their neuroprotective effects using an in vitro oxygen glucose deprivation (OGD) model of ischemic stroke. Some of the target compounds exhibited moderate to excellent protective potency. In particular, compounds 9d, 9e, 9g, and 9h showed significant protective effects in the SH-SY(5) Y cell line at all three concentrations tested.