Current Organic Synthesis - Volume 19, Issue 8, 2022

Significant advancement in the preparation of fascinating fluoroorganics is highly desirable in view of their limited natural occurrence and ever-increasing applications in medicinal and material sciences. Ionic liquids act as the most promising green media for a variety of nucleophilic and electrophilic fluorinations in terms of chemoselectivity, reaction yields, reusability, operational simplicity and scalability. The use of these designer solvents in stimulating the electrified synthesis of fluorinated compounds is also appreciable due to their tuneable electrochemical characteristics. Recent innovations in fluorination techniques depict the substantial role of ionic liquids in fluorotransformations such as the use of tagged ionic liquids in nucleophilic fluorinations, ionic liquid assisted biological fluorination, enantioselective fluorinations using chiral electrophilic reagents along with ionic liquid media, use of task-specific ionic liquids with mediators in electrochemical fluorinations and ionic liquid promoted electrifying synthesis of medicinally important fluorinated heteroaromatics and radiopharmaceuticals.

Ionic liquid functionalized mesoporous silica compounds present significant advantages in organic synthesis as catalysts. There are various preparation procedures for the synthesis of diverse ionic liquid catalysts, which have different catalytic properties with various roles in organic reactions. Therefore, due to the increment in the usage of mesoporous materials in the industry and numerous pieces of research, in this article, the information on the development of ionic liquids supported on SBA-15 between the years 2014 and 2021 was gathered.

Ionic liquids are one of the greener solvents which have emerged as a replacement for toxic and harmful volatile organic solvents. In the past decade, the concept of supported ionic liquids (SILs) has attracted the attention of the scientific community due to their unique chemical and physical properties. SILs can be synthesized by coating a thin layer of IL film onto/into the surface of solid support. They can be classified as supported IL phase catalyst, solid catalyst with IL and supported IL catalysis. SILs demonstrated the combined properties of both heterogeneous and homogeneous catalysts. These ILs offer several advantages such as enhanced stability, reusability, recoverability, easy product isolation, absence of IL leaching, as compared to conventional solvents. In this review, various aspects of SILs, classification, method of preparation and their applications in various organic transformations such as cross-coupling reactions, oxidation, reduction, synthesis of different heterocyclic compounds, biocatalytic reactions etc., have been discussed.

Background and Objective: As a key pharmacophore, the cyano group widely exists in a variety of biologically active compounds. Besides, nitriles are also valuable intermediates for many common functional groups. In this current work, a new synthesis strategy was developed to obtain nitriles from aldehydes. Methods: Using commercially available aldehydes as raw materials, and hydroxylamine and hydrochloride as nitrogen sources, the corresponding nitrile compounds were successfully synthesized by the one-pot method through the promotion of imidazole hydrochloride. And it was characterized by 1H NMR, 13C NMR, and mass spectrometry. Results: Various reaction conditions were applied in order to find an optimum and convenient procedure for the formation of nitriles. The highest yields (95%) were achieved using sulfolane as a solvent, and imidazole hydrochloride as a promoter. Conclusion: In conclusion, we developed a new synthetic method for nitrile compounds from aldehydes. Twenty seven examples of functionalized nitrile compounds have been synthesized in good to excellent yields. This methodology features that an environmentally benign imidazole hydrochloride replaces transition metal catalysts and oxidants required in conventional strategies to convert aldehydes into nitriles with good functional group tolerability. Further exploration of imidazole hydrochloride is ongoing in our laboratory.

Aims: This study aimed to recommend a novel way for the preparation of carbohydrates containing triazole derivatives. Background: Triazoles containing derivatives have numerous biological activities. Ball milling is a fast, modest, green process with massive potential. One of the greatest interesting applications of this technique is in the arena of heterocycles. Objective: Solvent-free click reactions are facilitated via the activation of copper powder using a ball milling mechanochemical procedure. An optimization study of parameters affecting the reaction rate, such as reaction time, size, and milling ball number, has been conducted. Different substrates have been tested using this adopted procedure considering in all cases, in high yields and purity, the corresponding chiral optically pure five-membered glycoconjugates containing 1,2,3-triazole. Methods: Three milling balls of 10 mm in diameter were placed in the milling jar (50 mL; stainless steel). 1 mmol of alkyne, 2 mmol of azide, and 1 mmol of Cu powder (63 mg) were added, respectively, in the presented order. Milling was assured for 25 min at 650 rpm deprived of solvent. Results: The cycloaddition results and the deprotection of the cycloadducts were affected by the selection of the protective groups. Cleavage of the acetyl protecting groups provided water-soluble triazoles. The four 1,4-di-substituted 1,2,3-triazoles synthesized via deacetylation were tested against glycogen phosphorylase. The best inhibitor of rabbit muscle glycogen phosphorylase was 2-Amino-3-{2-[1-(3,4,5,6-tetrahydroxytetrahydro- pyran-2-ylmethyl)-1H-[1,2,3]triazol-4-yl]-ethylsulfanyl}-propionic acid b (Ki = 40.8 ± 3.2 μM). This novel procedure affords an eco-friendly reaction profile (catalyst-free) affording high yields and short reaction times. Conclusion: In this work, acetyl protective groups were used to the corresponding deprotected watersoluble triazole analogous to recognizing glycogen phosphorylase inhibitors. Triazole 6a was the most effective inhibitor of RMGP b with a Ki value of 40.8 μM.