Current Organic Chemistry - Volume 27, Issue 4, 2023

Concerned about a million people are infected worldwide, and other millions are living at risk zones of infection. Chagas disease causes 10 000 deaths annually, and the discovery of safe and effective drugs on a nanomolar scale has been headlined as a crucial goal by the worldwide research community and international health agencies. Nifurtimox and Benznidazole are the only marketed drugs for Chagas disease therapy, with the mode of action depending on the formation of free radicals. Thus, diverse studies have revealed cysteine proteases from T. cruzi as well-established targets for drug discovery. Validation of cruzain as a promising target has been based on several findings on the molecular biology of T. cruzi. Hence, several inhibitor classes have been elucidated, consisting of peptidic and nonpeptidic, and covalent and noncovalent. Thus, we present a perspective for the synthesis of novel cruzain inhibitors from scaffolds both recently approached and well established with an IC50 range of micromolar to nanomolar and supported by computational techniques.

Immobilized lipase has played an essential role in the chemical and biological sciences as a viable alternative to standard chemical catalysts. Glutaraldehyde is a low-cost crosslinking agent at risk of being superseded by developing crosslinking compounds with biocompatible, biodegradable, and non-toxic characteristics. The multipoint covalent treatment method using glutaraldehyde has both advantages and disadvantages. Immobilization techniques can be improved to improve the overall performance of immobilized lipase. The most recent update on lipase immobilization with multipoint covalent treatment by glutaraldehyde was summarized in this review. Covalent binding lipase on pre-activated support and aggregation-crosslinking lipase into crosslinked enzyme aggregates (CLEAs) or adsorptioncrosslinking lipase on support are the most common immobilization techniques. Based on the above technologies, the advancement trends in important domains, such as the advancement of supports, additives, reactors, and cross-linking agents, are summarized. In addition, the application of the improved immobilized lipase by glutaraldehyde in the production of fatty acids, glycerides, biodiesel, and drug precursors was reviewed. In view of this, we put forward further studies on multipoint covalent treatment in lipase immobilization with glutaraldehyde. Various analytical methods are required to provide additional information about the structure of glutaraldehyde and its crosslinked products for assisting the proper immobilization conditions. Applying the composite strategy can also bring new opportunities for improving the efficiency of biological catalysts.

The current review focused on the various methods for synthesizing pyrido[2,3- d]pyrimidine derivatives and the reactions of pyrido[2,3-d]pyrimidine derivatives with important pharmaceutical and biological activities.

1,4-benzodiazepines play a valuable role in organic and medicinal chemistry. In this review article, we have mainly discussed the synthesis of various 1,4-benzodiazepines in the presence of a palladium catalyst. Different reactions, such as intramolecular N-arylation, reductive elimination, oxidative addition, intramolecular alkylation, C-H activation, aryl-aryl bond formation, etc., are included. For these types of syntheses, an easy and efficient catalytic domino process has been reported, including the intermolecular or intramolecular reactions. In this review article, we have also discussed catalyst regeneration and some ligand-free Pdcatalyzed reactions.

Click reactions have gained enormous popularity among chemists for their ambient reaction parameters and wide application in various frontier research fields. Photo-initiated click reactions add another dimension of spatiotemporal control which ensures fruitful bioorthogonal reaction. Several cycloaddition reactions, enlisted in the category of ‘photo click’ reactions due to the fast kinetics and ambient reaction conditions, are widely utilized by scientists for bioorthogonal conjugation. In this review, various types of 1,3-dipolar cycloaddition reactions and their applications in the field of protein bioconjugation are discussed.

Aurones, a member of the flavonoid family, have limited occurrence in nature and are relatively less explored than other flavonoids but still constitute a gleaming class of therapeutically significant oxygen heterocyclic molecules with broad-spectrum biological activities. These are secondary plant metabolites and are responsible for glaring pigmentation to various colored parts of the plants. This review covers the comprehensive history of aurones from 1918 to 2020. This review provides a generalized and systematic study of the protocols adopted for synthesizing aurone derivatives and their biological profile. Though there are many review articles on the biological activities of aurones, none of these cover the synthetic aspects of the protocols thoroughly. With the growing number of biologically active natural and synthesized aurones, a massive breakthrough in aurone research has emerged, and it is now one of the most researched O-heterocycles. The present review aims to highlight the work of the researchers on aurones to help synthetic chemists and future generations to design and develop new aurone-based heterocyclic systems of therapeutic potential. This review will also catch the attention of researchers for exploring various other potentials of aurones.

Organic light emitting diode (OLED) is a device that uses organic semiconductor materials to emit light under the action of an electric field. Compared with traditional luminescent materials, they have the advantages of good softness, low-temperature resistance, wider field of vision and low energy consumption, and have been widely used in the field of display and lighting in recent years. In addition, compared with red and green light-emitting materials, the maximum external quantum efficiency of blue-light materials-based devices is high, but the CIE coordinate performance is poor and the blue emission is difficult to achieve high efficiency and high color purity at the same time. Researchers continue to design new molecular structures in order to synthesize new high-efficiency blue light materials. It is found that different molecular structures have different effects on the performance of OLED devices. In the design and synthesis of blue-light materials, various light-emitting groups are often used to regulate the stability, singlet-third-line state of the target molecule energy level difference, excited state lifetime, aggregation state structure, electricity luminescent color and its OLED performance, etc. The introduction of different lightemitting groups into the blue light material greatly improves the performance of the material. This paper mainly reviews the research status of blue organic electroluminescent materials in the past five years from different molecular structures, further discusses the photoelectric properties of each compound and the properties of devices based on this material, and briefly analyzes the advantages of molecular design and device production. And finally discusses the improvement methods of blue OLED light-emitting materials in order to provide a reference for future research.

Anthracyclines are one of the most effective cancer treatments ever created, but these compounds are somewhat cardiotoxic to some patients, causing heart failure. The likelihood of such adverse effects restricts the overall prescribed dose of anthracyclines for patients. Based on the pathophysiology of anthracycline-induced cardiotoxicity, the cardiotoxicity plausibly originates from a reduction reaction of a single electron in its structure to form surplus reactive oxygen species (ROS) or two electrons reducing and converting into C-13 alcohol metabolites. While excess ROS is the probable cause for acute cardiotoxicity brought on by anthracyclines, it is not all characteristic of progressive cardiomyopathy. The formed secondary alcohol metabolites could also profoundly accelerate cardiotoxicity, which then develops into cardiomyopathy and eventually congestive heart failure. This review offers an overview of the molecular pathways of anthracycline-induced cardiotoxicity, emphasizing the roles of secondary alcohol metabolites of anthracyclines and/or their morbific role as ROS. The most effective ways to minimize or terminate anthracycline-induced cardiotoxicity are also covered.