Synthesis of 2‑Aryl-1,2-dihydrophthalazines via Reaction of 2‑(Bromomethyl)benzaldehydes with Arylhydrazines

The reaction of 2-(bromomethyl)­benz­aldehydes with arylhydrazines employing K₂CO₃ as a base and FeCl₃ as a catalyst in CH₃CN at 100 °C delivers 2-aryl-1,2-dihydrophthalazines with yields ranging from 60 to 91%. The transformation is considered to proceed as an intermolecular condensation/intramolecular nucleophilic substitution

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

Reaction of 1‑Nitroso-2-naphthols with α‑Functionalized Ketones and Related Compounds: The Unexpected Formation of Decarbonylated 2‑Substituted Naphtho[1,2‑<i>d</i>][1,3]oxazoles

Reactions between 1-nitroso-2-naphthols and α-functionalized ketones such as α-bromo-, α-chloro-, α-mesyloxy-, α-tosyloxy-, and α-hydroxy ketones under basic conditions delivered 2-substituted naphtho­[1,2-<i>d</i>]­[1,3]­oxazoles in a single synthetic operation. The product formation was accompanied by the unexpected loss of the CO group from the α-functionalized ketones. With aryl bromides, allyl bromides, α-bromo diketones, α-bromo cyanides, α-bromoesters, and α-bromo ketoesters as substrates the formation of naphtho­[1,2-<i>d</i>]­[1,3]­oxazoles was also observed. The transformations were performed in 1,2-dichloroethane or acetonitrile under reflux and gave the corresponding naphthoxazoles with yields ranging between 52% and 85%

Reaction of 1‑Nitroso-2-naphthols with α‑Functionalized Ketones and Related Compounds: The Unexpected Formation of Decarbonylated 2‑Substituted Naphtho[1,2‑<i>d</i>][1,3]oxazoles

Reactions between 1-nitroso-2-naphthols and α-functionalized ketones such as α-bromo-, α-chloro-, α-mesyloxy-, α-tosyloxy-, and α-hydroxy ketones under basic conditions delivered 2-substituted naphtho­[1,2-<i>d</i>]­[1,3]­oxazoles in a single synthetic operation. The product formation was accompanied by the unexpected loss of the CO group from the α-functionalized ketones. With aryl bromides, allyl bromides, α-bromo diketones, α-bromo cyanides, α-bromoesters, and α-bromo ketoesters as substrates the formation of naphtho­[1,2-<i>d</i>]­[1,3]­oxazoles was also observed. The transformations were performed in 1,2-dichloroethane or acetonitrile under reflux and gave the corresponding naphthoxazoles with yields ranging between 52% and 85%

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

Cu-Catalyzed Reaction of 1,2-Dihalobenzenes with 1,3-Cyclohexanediones for the Synthesis of 3,4-Dihydrodibenzo[<i>b,d</i>]furan-1(2<i>H</i>)‑ones

The Cu­(I)-catalyzed reaction of 1-bromo-2-iodobenzenes and other 1,2-dihalobenzenes with 1,3-cyclohexanediones in DMF at 130 °C using Cs₂CO₃ as a base and pivalic acid as an additive selectively delivers 3,4-dihydrodibenzo­[<i>b</i>,<i>d</i>]­furan-1­(2<i>H</i>)-ones with yields ranging from 47 to 83%. The highly regioselective domino process is based on an intermolecular Ullmann-type <i>C</i>-arylation followed by an intramolecular Ullmann-type <i>O</i>-arylation. Substituted products are accessible by employing substituted 1-bromo-2-iodobenzenes and substituted 1,3-cyclohexanediones as substrates. Reaction with an acyclic 1,3-diketone yields the corresponding benzo­[<i>b</i>]­furan