Mini-Reviews in Organic Chemistry - Volume 14, Issue 1, 2017

The use of ionic liquids to replace organic solvents in metal catalyzed reactions has recently gained much attention and great progress has been accomplished in this area in the last years. Therefore, considerable attention has been paid on the use of ionic liquids in chemical research. As the interest for environment increases and environmental laws become more stringent, the need to replace existing processes with new more sustainable technologies becomes a primary objective. The efficiency of a chemical synthesis can be nowadays measured, not only by parameters like selectivity and overall yield, but also by its raw material, time, human resources and energy requirements, as well as the toxicity and hazard of the chemicals and the protocols involved. Modern synthetic chemistry is benefited as ionic liquid methodology provided an environmentally benign approach. The multicomponent reactions in the presence of task-specific ionic liquids are used not only as environmentally benign reaction media, but also as catalysts. In comparison to traditional processes the use of ionic liquids resulted in improved, complimentary or alternative selectivities in organic synthesis. This review focuses on the advances in the development of innovative applications of ILs for the synthesis of N-heterocycles.

Rhaponticin (RHA) is a stilbene glucoside compound that can be found in medicinal plant of Rheum L. RHA has been reported to possess several biological effects including antitumor, antithrombotic, antioxidant, vasorelaxant, defense for gastritis activities. It also shows beneficial activities on diabetic mice. According to reported literatures, an overview of spectroscopy characteristics, pharmacological activity, content determination and pharmacokinetics, etc. for RHA has been presented. Moreover, this work provides a certain reference value for developing the therapeutic drug of RHA.

Synthesis methods of cyclic polyesters and oligoesters are reviewed with a focus on cyclic poly(lactic acid) and oligo(lactic acid) (OLA). Two approaches are generally used to obtain cyclic polyesters: 1) the extraction of cyclic polyesters as by-products contained in the polymerized product obtained via direct polycondensation and 2) synthesis from an ester monomer with an appropriate catalyst. Among the cyclic polyesters obtained with these approaches, compounds with a particular degree of polymerization tend to express specific function, such as including alkali metal ions interacting with the carbonyl group toward the inside of the ring in an organic solvent. This inclusion behavior may affect the transportation of ions within an organism leading to effects such as the antitumor activity of cyclic oligo(lactic acid).

Due to the increasing interest in the replacement of the environmentally toxic lube and fuel additives obtained from non-renewable raw materials by eco-friendly/biodegradable additives from renewable resources in order to meet the growing demand and to minimize the environmental impact caused by their use and disposal, this paper aims to present a short review compiling some recent efforts made to develop the eco-friendly additives through organic transformations of biomaterials.

Background: Nanotechnology has received considerable attention and developed rapidly due to some superior properties of nanomaterials. As one of the most important conductive materials, polyaniline with various nanostructures have shown good environmental stability, charge transport capacity, ease of synthesis, flexibility in processing and good biocompatibility. They have been used in many fields such as solar battery, electroluminescence, electromagnetic shielding, rechargeable batteries, material corrosion protection and biomedical applications. Objective: We mainly review the synthesis, dispersion techniques of polyaniline nanoparticles so that they can be well dispersed and more widely used in biomedical field. Method: We searched and collected more than one hundred references, focused on the methods for synthesis, dispersion and biomedical applications of polyaniline nanoparticles. Results: The synthesis methods of polyaniline nanoparticles mainly include micro-emulsion polymerization, interfacial polymerization, a pulsed potentiostatic method et al. The dispersion method of polyaniline nanoparticles can be classified as chemical method and physical method. Biomedical applications of polyaniline nanoparticles in biosensors, neural probes, tissue engineering and photothermal therapy for cancer are also discussed. Conclusion: This review provides the comprehensive collections of information that has clearly given ideas of methods for preparation and dispersion of polyaniline nanoparticles and their recent advanced biomedical applications.

The use of ionic liquids (ILs) and supercritical fluids (SCFs), as alternative non-aqueous reaction media for carrying out selective biocatalytic transformations, has substantially increased the opportunities for developing clean and sustainable chemical processes with industrial interest, which were enhanced by combination with continuous flow systems. The excellent suitability of ILs to over-stabilize enzymes, combined with the excellences of supercritical carbon dioxide (scCO2) to dissolve and transport chemicals, provides useful synergies for designing continuous clean synthetic approaches, that directly provide pure products by using appropriate reactor (e.g. membrane reactors). Several examples (i.e. DKR of sec-alcohols, synthesis of biodiesel, etc.), where the use of continuous flow techniques with multi-catalytic synthesis are combined into a single continuous operation, are provided in this paper.

Low-molecular-mass organic acids (LMMOA) and their behaviour in forest soil are reviewed. LMMOA are a part of the carbon cycle, and represent an important component of the active organic carbon. Low-molecular-mass organic acids are being constantly released to soil from root exudates, microbial activities, and organic matter decomposition. Other main sources include deposition (atmospheric or throughfall). This review describes the origin of LMMOA in forest soils, and the methods for determination of LMMOA in soil solution and for the storage of LMMOA samples. Methods of LMMOA analysis are discussed in greater detail. Generally, one of the most promising methods for determination and speciation of LMMOA seems to be IC-MS; HPLC is suitable method when strong extraction reagent is used.

Hypertension is recognized as an important global public-health challenge. High blood pressure is the foremost controllable risk factor for morbidity and mortality and is a major independent risk factor for the development of coronary artery disease, stroke, and renal failure. The hypertension affected overall, 26.4% of world’s adult population in 2000, and the figure is expected to increase by about 60%; i.e. to 29.2% of total adult population by the year 2025. There are several therapeutic options for the management of hypertension, dependent upon the overall status of disease. The Angiotensin Converting Enzyme (ACE) inhibitors are rated as first-line treatment in the effective management of hypertension. However, the current AEC inhibitors in clinical practice are nonselective inhibitors and thus causing several unwanted effects. Therefore, new selective inhibitors have been focused around the world by various researchers for the discovery safer agents. The phytopharmaceuticals such as alkaloids have a marvelous therapeutic history and numerous alkaloids are in clinical use, therefore it could be an ideal approach to study for the design of selective inhibitors. This review encountered the so far tested alkaloids and their significant results thus suggested further study of these and many, more alkaloids for the discovery of new effective and selective ACE inhibitors. Furthermore, the application of modern pharmaceutical technologies could be helpful in the effective design of agents.