Squaric acid: an impressive organocatalyst for the synthesis of biologically relevant 2,3-dihydro-1H-perimidines in water

A Target Responsive Metal Organic Framework Derived Bimetallic Apta-Switch for Reagentless Molecular Recognition

By integrating iron-cobalt squarate bimetallic metal-organic framework (Fe-Co-SqBMoF) based smart material (SM) with functional DNA (fDNA), we designed a target responsive fDNA@Fe-Co-SqBMoF bioelectrode that exhibits recognition induced switchable response to serve as a reagentless single step electrochemical apta-switch (REA). The construct takes advantage of fDNA ability to bind and concentrate target on the receptor interface, while Fe-Co-SqBMoF@SM multifeatures to serve as an immobilization matrix and a signal generating electrochemical switch. Fe-Co-SqBMoF was introduced to prepare a redox active pencil graphite electrode (PGE), while fDNA (aptamer) was decorated on the receptor PGE to impart specificity and selectivity. The Fe-Co-SqBMoF synthesis was characterized through X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, micro-Raman spectroscopy, dynamic light scattering (DLS), and UV-visible (UV-vis) analysis, while each step of fDNA decoration and bioelectrode fabrication was characterized via field emission scanning electron microscopy (FE-SEM), static water contact angle measurements, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). To explore the potential application of the fDNA@Fe-Co-SqBMoF bioelectrode, we designed a REA for detection of aflatoxin B1 (AFB1) which permitted the detection of AFB1 in the linear range 0.7-1000 pg/mL with an LOD of 0.54 pg. The practical applicability of an fDNA@Fe-Co-SqBMoF based REA was demonstrated in milk and water samples.

Advances in organocatalyzed synthesis of organic compounds

The recent advancements in utilizing organocatalysts for the synthesis of organic compounds have been described in this review by focusing on their simplicity, effectiveness, reproducibility, and high selectivity which lead to excellent product yields. The organocatalytic methods for various derivatives, such as indoles, pyrazolones, anthrone-functionalized benzylic amines, maleimide, polyester, phthalimides, dihydropyrimidin, heteroaryls, N-aryl benzimidazoles, stilbenoids, quinazolines, quinolines, and oxazolidinones have been specifically focused. The review provides more understanding by delving into potential reaction mechanisms. We anticipate that this collection of data and findings on successful synthesis of diverse compound derivatives will serve as valuable resources and stimulating current and future research efforts in organocatalysis and industrial chemistry.

Study on cellulose nanofibrils/copolymacrolactone based nano-composites with hydrophobic behaviour, self-healing ability and antioxidant activity

The multiple uses of cellulose nanofibrils (CNFs) originate from their availability from renewable resources, and are due to their physico-chemical properties, biodegradability and biocompatibility. At the same time, reducing sensitivity to humidity, increasing interfacial adhesion and hydrophobic modification of the CNF surface to diversify applications and improve operation, are current targets pursued. This study focuses on the preparation of a novel gel structure using cellulose nanofibrils (CNFs) and poly(ethylene brassylate-co-squaric acid) (PEBSA50/50), a bio-based copolymacrolactone. The primary goal is to achieve the gel with reduced sensitivity to humidity and enhanced hydrophobic behaviour. The new system was characterized in comparison to its constituent components using various techniques, such as Fourier transform infrared spectroscopy, thermal analysis, X-ray diffraction, and NIR - chemical imaging. Rheological tests demonstrated the formation of the CNF_PEBSA50/50 gel as a result of physical interactions between the two polymeric partners and revealed self-healing abilities for the prepared gels. Determination of the contact angle, surface free energy, as well as dynamic measurements of the vapour sorption of the CNF_PEBSA50/50 system, confirmed the achievement of the study's aim. Furthermore, the CNF_PEBSA50/50 network was utilized to encapsulate citric acid, resulting in the creation of a new bioactive composite with both antioxidant and antimicrobial activity.

p-Toluenesulfonic acid-promoted organic transformations for the generation of molecular complexity

Since the beginning of this century, p-toluenesulfonic acid (p-TSA) catalysed organic transformations have been an active area of research for developing efficient synthetic methodologies. Often, catalysis using p-TSA is associated with many advantages, such as operational simplicity, high selectivity, excellent yields, and ease of product isolation, which make organic synthesis convenient and versatile. Notably, p-TSA is a non-toxic, commercially available, inexpensive solid organic compound that is soluble in water, alcohols, and other polar organic solvents. p-TSA is a strong acid compared to many protic or mineral acids and its high acidity helps activate different organic functional groups. p-TSA-promoted conversions are fast, have a high atom and pot economy, and feature a multiple bond-forming index. Therefore, the utilization of p-TSA enables the synthesis of many important structural scaffolds without any hazardous metals, making it desirable in numerous applications of sustainable and green chemistry. Recently, this emerging area of research has become one of the pillars of synthetic organic chemistry to synthesise biologically relevant, complex carbocycles and heterocycles. This study provides a comprehensive summary of methods, applications, and mechanistic insights into p-TSA-catalysed organic transformations, covering the literature reports that have appeared since 2012.

2-(1H-Imidazol-2-yl)-2,3-dihydro-1H-perimidine

The novel compound 2-(1H-imidazol-2-yl)-2,3-dihydro-1H-perimidine was obtained in very good yield via a known eco-friendly protocol. The product was isolated in pure form as a solvate by simple filtration from the crude mixture. Its structure was assigned by 1D and 2D NMR experiments and was confirmed by high resolution MS and single crystal XRD. The temperature of methanol release was determined by DSC and the energy of the process theoretically estimated.

Recent Advances in the Synthesis of Perimidines and their Applications

Perimidines are versatile scaffolds and a fascinating class of N-heterocycles that have evolved significantly in recent years due to their immense applications in life sciences, medical sciences, and industrial chemistry. Their ability of molecular interaction with different proteins, complex formation with metals, and distinct behavior in various ranges of light makes them more appealing and challenging for future scientists. Various novel technologies have been developed for the selective synthesis of perimidines and their conjugated derivatives. These methods extend to the preparation of different bioactive and industrially applicable molecules. This review aims to present the most recent advancements in perimidine synthesis under varied conditions like MW radiation, ultrasound, and grinding using different catalysts such as ionic liquids, acid, metal, and nanocatalyst and also under green environments like catalyst and solvent-free synthesis. The applications of perimidine derivatives in drug discovery, polymer chemistry, photo sensors, dye industries, and catalytic activity in organic synthesis are discussed in this survey. This article is expected to be a systematic, authoritative, and critical review on the chemistry of perimidines that compiles most of the state-of-art innovation in this area.