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The article discusses the use of the inverse-electron-demand Diels-Alder (IEDDA) reaction as a synthetic tool for creating complex molecular structures. The authors focus on the use of bidentate Lewis acid catalysts to facilitate the IEDDA reaction between phthalazines and cyclooctynes. They found that the catalyst significantly increased the reaction rate and yield of the desired products. The authors also explored the scope of the reaction by testing different substituted phthalazines and cyclooctynes. The method presented in the article provides a convenient and efficient way to synthesize polycyclic aromatic hydrocarbons fused to eight-membered carbocycles. [Extracted from the article]

This article explores the use of palladium-catalyzed acylation reactions in organic synthesis. The authors emphasize the significance of the carbonyl group in organic chemistry and the limitations of traditional methods for creating ketones. They present their own research on a Pd-catalyzed direct acylation method that allows for the synthesis of various ketones without the need for directing groups. The authors also investigate the synthesis of benzofuranones and indenones using sequential one-pot operations. Overall, this article offers valuable insights into the development of innovative synthetic strategies for producing biologically relevant substances. [Extracted from the article]

The resulting solution was evaporated under reduced pressure to give the crude product, which was further purified by column chromatography on silica gel (20% EtOAc/hexane) to furnish B 30 b (49.5 mg, 0.19 mmol, 58%) as a white solid; mp 107.4-107.7 °C. The resulting solution was evaporated under reduced pressure to give the crude product B 29 b , which was further purified by column chromatography on silica gel (20% EtOAc/hexane) to furnish B 29 b (10.5 mg, 0.04 mmol, 75%) as a clear sticky oil. Keywords: epoxidation; cyclization; carbocation; fused-ring systems; stereoselectivity EN epoxidation cyclization carbocation fused-ring systems stereoselectivity 2757 2772 16 08/17/23 20230901 NES 230901 Graph Various oxacycles are privileged scaffolds in pharmaceutical industries, cosmetics, natural products, and drug discovery, among others. TOF-HRMS: I m i / I z i [M + Na] SP + sp calcd for C SB 19 sb H SB 20 sb O SB 4 sb Na: 335.1254; found: 335.1247. tert -Butyldimethyl((3-phenyl-1,3-dihydroisobenzofuran-1-yl)methoxy)silane (26b') By following the General Procedure G, and purification by column chromatography on silica gel (20% EtOAc/hexane), the product (24.0 mg, 0.71 mmol, 44%) was obtained as a yellow sticky gum. [Extracted from the article]

An efficient and convenient palladium-catalyzed reductive system by employing sodium hydride as the hydrogen donor and acetic anhydride as an activator has been developed for transfer hydrogenation and acetylation of a wide range of N -heteroarenes including quinoline, phthalazine, quinoxaline, phenazine, phenanthridine, and indole. Moreover, acridine substrates could be directly reduced without the use of acetic anhydride. This protocol provides a simple method for the preparation of various saturated N -heterocycles. [ABSTRACT FROM AUTHOR]

A practical method for the synthesis of hydroxyalkylated indolo[2,1- a ]isoquinoline derivatives through the metal-free cascade cyclization of 2-arylindoles with alcohols in the presence of tert -butyl hydroperoxide (TBHP) is disclosed. The present method features transition-metal-free conditions and exceptional functional group tolerance. A series of valuable hydroxyalkylated indolo[2,1- a ]isoquinoline derivatives bearing various functional groups is synthesized in moderate to excellent yields. [ABSTRACT FROM AUTHOR]

An unprecedented N -chlorinative ring contraction of 1,2-diazines was discovered and investigated with an electrophilic chlorinating reagent, trichloroisocyanuric acid (TCICA). Through optimization and mechanistic analysis, the assisting role of n -Bu4 NCl as an exogenous nucleophile was identified, and the optimized reaction conditions were applied to a range of 1,4-dimethoxyphthalazine derivatives. Also, an improvement of overall efficiency was demonstrated by the use of a labile O -silyl group. A bicyclization/ring-opening mechanism, inspired by the Favorskii rearrangement, was proposed and supported by the DFT calculations. Furthermore, the efforts on scope expansion as well as the evaluation of other electrophilic promoters revealed that the newly developed ring contraction reactivity is a unique characteristic of 1,4-dimethoxyphthalazine scaffold and TCICA. [ABSTRACT FROM AUTHOR]

An efficient, one-pot, three-component [3+2] cycloaddition reaction of azomethine ylide obtained from α-dicarbonyl compounds (cyclic and acyclic diketone or keto ester) and amino acids with maleimides under catalyst-free conditions has been developed. This cascade protocol shows high efficiency and remarkable functional group tolerance, and the ubiquitous succinimide-fused pyrrolizidines with a highly compact and strained scaffold were obtained with high yield and excellent diastereoselectivity. Furthermore, this novel and atom-economical strategy could be performed on a gram scale with comparable reaction efficiency. [ABSTRACT FROM AUTHOR]

The need to access different heterocyclic cores as part of p38 MAP kinase inhibitors led to the discovery and development of several efficient approaches to three separate classes of heterocycles, namely phthalazines, pyrazolopyridinones, and triazolopyridines. This account summarizes our studies in this field in a comprehensive fashion. 1 Introduction 2 Synthesis of Phthalazine-Based p38 Inhibitors 2.1 Synthesis of Clinical Candidate 2 2.2 Synthesis of Clinical Candidate 3 3 Synthesis of Pyrazolopyridinone-Based p38 Inhibitors 4 Synthesis of Triazolopyridine-Based p38 Inhibitors 4.1 Synthesis through Pd-Catalyzed Benzhydrazide Couplings 4.2 Synthesis through Pd-Catalyzed Benzhydrazone Couplings 5.0 Conclusions. [ABSTRACT FROM AUTHOR]

An efficient, three-component, one-pot condensation reaction between phthalhydrazide, aromatic aldehydes, and malononitrile or ethyl cyanoacetate for the synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-dione derivatives in excellent yields is reported. [ABSTRACT FROM AUTHOR]