Current Organic Chemistry - Volume 20, Issue 3, 2016

The goal of this review is to provide a comprehensive overview of the developments in enantioselective two- and multicomponent domino reactions as well as tandem sequences catalyzed by chiral nickel complexes, covering the literature since the beginning of 2004. Related to the lower costs of nickel catalysts in comparison with other transition metals, enantioselective nickel-catalyzed domino and sequential tandem processes have been widely developed in the last decade, allowing a fast and easy approach to complex chiral products in single steps.

Fluorescent probes possess low limit, high sensitivity, and wide response range, etc. but they have some disadvantages including contamination to the detection system, limitation of repeated use. Polymers combined with fluorescent probes could overcome these drawbacks and they have been widely used in chemosensor, biological imaging and PH/temperature sensor for their unique favorable mechanical properties and good workability. In this review, we mainly reviewed organic and inorganic fluorescent probe polymers, focusing on synthetic methods, properties and applications. Their specific structural designs, synthetic strategies and different polymeric material on the optical properties and applications are subsequently summarized. With further advances in the design and synthesis of multifunctional fluorescent polymers with high quality, the widespread application of them could be expected in advanced bioimaging, ultrasensitive molecular diagnosis and novel light-emitting nanodevices.

This review supplies the reader with a detailed overview on the utilization of intramolecular processes for a design and synthesis of prodrugs. It is well known that a respected number of drugs suffer from low bioavailability, toxicity, unpleasant taste and presystemic first-pass metabolism which result in drug inactivation. The classical prodrug approach in which the linkage attaching the parent drug to its non-toxic linker and cleaved by in vivo enzyme’s catalyzed reactions has proven its success in solving toxicity and bioavailability related issues. On the other hand, prodrugs based on chemical interconversion in which the prodrug releases the corresponding active parent drug via inter or intramolecular chemical process in the absence of an enzyme is considered as a better alternative approach since the prodrug cleavage is not dependent in the efficiency or quantity of the enzyme catalyzes the interconversion of the prodrug. Examples of successful prodrugs using the chemical approach via intramolecular processes such as cyclization reactions are illustrated as well. In addition, another part of this review is devoted to cover reported studies on enzyme models and their utilization for the design and synthesis of a variety of novel prodrugs. In this approach, computational calculations using DFT and MM methods were exploited and correlations between experimentally determined and computed values of the rate-limiting step in the studied intramolecular processes were utilized in the prodrugs design. Selected examples of the designed prodrugs include aza-nucleosides for the treatment of myelodysplastic syndromes, the anti-Parkinson’s agent dopamine, the anti-viral acyclovir, the anti-malarial atovaquone, and statins for lowering cholesterol levels in the blood, the antihypertensive atenolol, the antibacterial cefuroxime, the anti-bleeding tranexamic acid, the decongestant phenylephrine, and the pain killer paracetamol.

An efficient and convenient nanocrystalline MgO catalyzed one pot preparation of double Schiff bases via solvent free method is described. This protocol was designed through treatment of salicylaldehyde (or furfural) with various aromatic aldehydes and NH4OOCPh to afford double Schiff bases in high purity, excellent yields and short reaction times. These compounds are used as significant ligands that can be coordinated with different transition metal ions in order to be used in various applications like catalysis in organic synthesis. The advantages of this method are availability of starting materials, simplicity of the reaction, easy work up procedure, eco-friendly catalyst, green protocol and purity of products. The products were characterized by physical data and spectroscopic techniques such as; FT-IR, 1H NMR, 13C NMR, C.H.N. and Mass spectra.