One-pot multi-component synthesis of N,N′-alkylidene bisamides and imidazoles using heteropoly-11-tungsto-1-vanadophosphoric acid supported on natural clay as catalyst: A green approach

Advances in Organic Synthesis and Properties Based On Tetraphenylimidazole Derivatives

1,2,4,5-Tetraphenylimidazole derivatives exhibit unique conjugated structures, photophysical properties, and multifunctional properties by virtue of the phenyl functional groups introduced at specific positions of the imidazole ring. However, there is still a lack of systematic research on them, which limits their further development and application. In this paper, we comprehensively review the research progress in the fields of organic synthesis, mechanistic fluorescence color change, chemiluminescence, OLED and fluorescent sensors, especially focusing on the hotspot of fluorescent sensors. Finally, it summarizes the challenges in the current research and looks forward to the future research directions, such as the design of novel structures, performance optimization, and exploration of practical applications, aiming to provide references and inspirations for researchers in related fields.

Fabrication of a novel graphene oxide based magnetic nanocomposite and its usage as a highly effectual catalyst for the construction of N,N'-alkylidene bisamides

At first, a novel graphene oxide-based magnetic nanocomposite namely Si-propyl-functionalized N 1,N 1,N 2,N 2-tetramethylethylenediamine-N 1,N 2-diium hydrogen sulfate anchored to graphene oxide-supported Fe3O4 (nano-[GO@Fe3O4@R-NHMe2][HSO4]) was fabricated. After full characterization of the nanocomposite, its catalytic performance was examined for the solvent-free construction of N,N'-alkylidene bisamides from aryl aldehydes (1 eq.) and primary aromatic and aliphatic amides (2 eq.), in which the products were acquired in short times (15-30 min) and high to excellent yields (89-98%). Nano-[GO@Fe3O4@R-NHMe2][HSO4] could be magnetically isolated form the reaction medium, and reused three times without remarkable loss of catalytic activity.

Fragment-Based Design and Synthesis of Symmetrical bis-Peptidotriazoles Using Alkylidene bis-Amide Formations and Subsequent Triazole Ligation with β-Acetamido Carbonyl Scaffolds

A novel and efficient fragment-based assembly of symmetrical bis-peptidotraizoles has been developed based on double Sharpless azide-alkyne click chemistry. A new Cu(II) catalyzed protocol with a wide substrate scope was developed for accessing the symmetrical alkylidene bis-azidoamide fragment that yields the products in very good yields at room temperature without employing column purifications. The propargylated β-acetamido ketone fragment was accessed using another Cu(II) catalyzed room temperature MCR protocol. A fast double-click reaction (2 h) of symmetrical alkylidene bis-azidoamides with propargylated β-acetamido ketone fragments leads to the formation of unusual symmetrical bis-peptidotriazoles.

Clay based heterogeneous catalysts for carbon-nitrogen bond formation: a review

Clay and modified clay-based catalysts are widely used in organic transformation. Owing to the interlayer ions and good ion exchange capacity of clay, replacement with another ion and incorporation of different nanomaterials can be done. Due to these significant properties of clay, it can be utilized in the synthesis of various organic compounds. Carbon-nitrogen bonded compounds possess diverse applications in different fields. These compounds are prepared using different solid acid heterogeneous catalysts. This review presents a detailed discussion on clay used for the carbon-nitrogen bond formation reaction, such as the Biginelli reaction and A3 and KA2 coupling reactions. Additionally, other C-N bond formation reactions using various clay-based catalysts such as bentonite, montmorillonite, hydrotalcite and halloysite clay with various metals, metal oxides, Kegging type heteropoly acid and various nanomaterial incorporated clay heterogeneous catalysts are discussed.

An efficient green protocol for the synthesis of 1,2,4,5-tetrasubstituted imidazoles in the presence of ZSM-11 zeolite as a reusable catalyst

In this study, we have synthesized a series of ZSM-11 zeolite catalysts using tetrapropyl ammonium hydroxide as a structure-directing agent through a highly efficient hydrothermal method. The series of catalysts were studied by different techniques such as FT-IR spectroscopy, XRD, FE-SEM, HR-TEM, EDS, pyridine-FT-IR spectroscopy, and BET analysis. We focused on varying reaction time intervals from 18 to 48 hours to investigate the effect on catalytic activities of the synthesized series of catalysts. The percentages of aluminum increased in the framework of zeolites with increasing crystallinity, surface area, external surface area, and acidity in the series of ZSM-11 zeolites by increasing the time from 18 to 48 h. Then, we studied the catalytic activity of a series of ZSM-11 zeolites and found that the ZSM-11 zeolite (48 h) possesses higher catalytic activity towards the synthesis of 1,2,4,5-tetrasubstituted imidazoles under solvent-free conditions. The present protocol scored well with excellent yield, short reaction time, clean reaction profiles, low catalyst loading, and no tedious workup. The catalyst (ZSM-11 zeolite 48 h) was recycled and reused in five runs without any considerable loss of activity and product yield.

N,N,N′,N′-Tetramethylethylene-diaminium-N,N′-disulfonic acid trifluoroacetate and pyridinium-N-sulfonic acid hydrogen sulfate as highly effective dual-functional catalysts for the preparation of N,N′-alkylidene bisamides

In this research, Brønsted-acidic ionic liquids N,N,N′,N′-tetramethylethylene-diaminium-N,N′-disulfonic acid trifluoroacetate ([TMEDSA][TFA]2) and pyridinium-N-sulfonic acid hydrogen sulfate ([Py-SO3H][HSO4]) have been introduced as dual-functional catalysts for the green, simple and effective preparation of N,N′-alkylidene bisamides by the reaction of primary amides (2 eq.) with arylaldehydes (1 eq.) under solvent-free conditions. The reaction results and conditions of the catalysts have been compared with the previously reported ones. [TMEDSA][TFA]2 and [Py-SO3H][HSO4] were superior to the previously reported catalysts in terms of two or more of these factors: reaction times (10–45 min), yields (86–98%), temperature and the reaction conditions. Additionally, a plausible and attractive mechanism based on dual functionality of the catalysts has been proposed.