Mini-Reviews in Organic Chemistry - Volume 15, Issue 5, 2018

Noscapine is an opium alkaloid which has been historically used as an anti-tussive medicine. Its activity is attributed to its ability to bind stoichiometrically to tubulin, thus arresting cell division at the metaphase stage and leading to apoptosis. Its action as a safe, low toxicity drug has been confirmed and many different routes of synthesizing its naturally occurring, biologically active (-)-α isomer have been established. While noscapine has many advantages over present anti-cancer drugs - such as low toxicity, safety, high bioactivity (especially against drug-resistant strains of cancer) and oral administration - it faces the drawback of requiring a large Effective Dose (ED50) to show significant bioactivity. The analogues of noscapine show much higher activity, making these compounds more desirable as anti- cancer agents. This review explores in-depth the chemistry of noscapine and its analogues synthesized till date, including brief discussions about the bioactivity of different derivatives. In the coming years, noscapine and its analogues will present an exciting avenue for cancer therapeutics.

The efficient construction of C-C bonds with multiple stereocenters has been of synthetic interest to the synthetic community. This review describes the organocatalytic cascade, domino or tandem synthesis of spirocarbocycles that evolved through the use of small organic catalysts. Spirocarbocycles are frequently observed in organic compounds in nature, and the formation of spirocarbocycles is vital in contemporary organic synthesis. These reactions proceed through the combination of enamine, iminium, dienamine, and trienamine modes of activation to construct multiple C-C bonds with newly generated stereogenic centers.

This paper describes the importance of lipases as biocatalysts in various organic applications. Additionally, the influence of different immobilization techniques of enzymes on their catalytic activity and operational stability were investigated. There are many factors affecting the effectiveness and stereoselectivity of lipases in reactions of kinetic resolution. However, the optimization of reaction parameters is essential to obtain high yields of enantiopure products.

Catecholamine neurotransmitters are crucial molecules for physiological processes in human metabolism and are involved in the progression of various neurological diseases. Conventional analytical methods for their determination are based on time-consuming and laboratory intensive procedures. Hence, a rapid and simple method for the detection of these key brain chemicals is important to improve the human health and individual quality of life. This can also be helpful to diagnose neurological disorders at an early stage and to prevent them. In this paper, a brief overview is presented on the latest developments and applications of electrochemical sensors based on nanostructured tin dioxide (SnO2) for monitoring some of the most important catecholamine neurotransmitter substances, i.e. dopamine, epinephrine, and norepinephrine. The potential of these novel electrochemical devices and their outstanding performances in the field are highlighted.

Soil Organic Matter (SOM) is an important component in the global carbon cycle, including more than three times as much carbon as both the atmosphere and the terrestrial vegetation. However, it is difficult to analyze soil organic matter chemistry due to its complexity and diversity resulting from microbial and physicochemical transformations of organic remains of vegetal, microbial and animal origins. Pyrolysis–gas chromatography–mass spectrometry (Py-GC/MS) is a quick analytical technique to obtain clarity in molecular components in which the sample is heated to decomposition to produce smaller molecules that are separated by gas chromatography and detected using mass spectrometry. In the recent years, SOM chemical characteristic of different ecosystems has been studied with its responses to climate change and human activity. The goal of this review is to highlight chemical characteristic of SOM at the molecular level, and to compare soils under different ecosystems, further to illuminate a given soil under various impacts, such as climate conditions, land use change, cultivation pattern and fire disturbance, based on Py-GC/MS analytical technique.

The carbohydrate derived non-ionic gemini surfactants have emerged as a result of our present day interest in environmentally compatible chemicals. The literature, including patents, describing the emerging area of carbohydrate derived non-ionic gemini surfactants is reviewed. The present review paper deals with synthesis, surface-active properties and biological properties of carbohydrate derived non-ionic gemini surfactants. The application of these surfactants in solubilization process, emulsification, nanotechnology, and gene and drug delivery systems has been described.

Wittig- and Horner-Wadsworth-Emmons (HWE) olefination remains a series of powerful reactions in the tool kit of organic synthesis. In the following article, an overview of the scope of Wittig and HWE olefination reactions in water or in multiphasic media under phase transfer conditions is presented. Special emphasis is given to one-pot, multi-component transformations. In the following article, the work on Wittig- and Horner-Wadsworth-Emmons reactions in aqueous media and under LL-PTC conditions is reviewed.

Six-membered chalcogen, element (S, Se, N)-containing heterocycles attracted attention due to their biological activities. This mini-review presents methods for the preparation of these heterocycles modified by introduction of two chloromethylidene groups into their molecules. Methods for the synthesis of bis(1,3-dihalogeno-1-propen-2-yl) chalcogenides and their oxides, and methods of their heterocyclization with sodium sulfide and selenide, hydrazine and amine are reviewed as well as subsequent chemical transformation of the resulting heterocycles. Due to the presence of these moieties, further modifications of these heterocycles by the nucleophilic substitution and cross-coupling reactions are possible and presented in the mini-review.