Base-Promoted Domino Reaction of 5‑Substituted 2‑Nitrosophenols with Bromomethyl Aryl Ketones: A Transition-Metal-Free Approach to 2‑Aroylbenzoxazoles

The reaction of 5-substituted 2-nitrosophenols with bromomethyl aryl ketones and related compounds employing K₂CO₃ as a base in refluxing THF and DMF at 80 °C, respectively, delivers 2-aroylbenzoxazoles in a single step with yields up to 85%. The new method involves an intermolecular nucleophilic substitution followed by intramolecular 1,2-addition and elimination. It allows an efficient and practical access to 2-aroylbenzoxazoles under transition-metal-free conditions

Copper(I)-Catalyzed Intramolecular O‑Arylation for the Synthesis of 2,3,4,9-Tetrahydro‑1<i>H</i>‑xanthen-1-ones with Low Loads of CuCl

As little as 0.5 mol % CuCl is sufficient to catalyze the intramolecular O-arylation of easily accessible 2-(2-bromobenzyl)­cyclohexane-1,3-diones to provide the corresponding 2,3,4,9-tetrahydro-1<i>H</i>-xanthen-1-ones with yields ranging from 83% to 99%

Synthesis of 4<i>H</i>-3,1-Benzothiazin-4-Ones <i>via</i> C-N/C-S Bond Forming Reactions

A Phosphine-free and effective process has been expressed for the formulation of N,S-heterocycles following a C-N/C-S bond forming reactions. The described process operates through EDC-HCl-mediated heterocyclization of diverse isothiocyanates and bis-nucleophiles to deliver 1,3-thiazinone derivatives, which eliminates the use of hazardous reagents. The developed protocol was found applicable over a wide range of substrates in delivering N,S-heterocycles in excellent yields at room temperature and short reaction time.</p

Design, Synthesis, Biological Activity, and Molecular Modeling of Novel Spiroquinazoline Derivatives as Acetylcholinesterase Inhibitors for Alzheimer Disease

The p-toluene sulfonic acid (p-TSA) catalyzed cascade ring closing transformation has been executed for the preparation of novel spiroquinazolinone compounds 4 and 5 by the reaction between anthranilamide and cyclohexanone followed by subsequent acylation. These molecules were then examined against the inhibitory activity of Acetylcholineterase (AchE). The tested compounds revealed moderate anti-AChE activity of IC50 values ranging from 46.675 to 14.256 µM). The described results lead toward the development of compounds 4b and 5c having promising anti-AChE activities with IC50 values at the micromolar level. The docking study suggests that these hybrid spiroquinazolinone scaffold might facilitate the further development of investigated compounds as anti-Alzheimer agents.</p