Current Organic Chemistry - Volume 23, Issue 14, 2019

The conversion of organic wastes into biodiesel has become an attractive solution to address waste surplus problems and energy depletion. Oleaginous insects can degrade various organic wastes to accumulate fat-based biomass, thus serving as a potential feedstock for biodiesel production. Therefore, the use of insects fed on organic waste for biodiesel production has increasingly attracted considerable investigations. In recent years, different insect species have been studied for their efficiency in converting various organic wastes and for producing biodiesel from their fat. Several methods have been developed for biodiesel production from insects to improve yields and reduce production costs and environmental impacts. This review summarizes the latest findings of the use of insects for converting organic wastes into biodiesel. The production processes and fuel properties of biodiesel produced from insects are also discussed.

The rapidly increasing demand for biodiesel is now tying agriculture and energy more closely than ever. Biodiesel may be one of the key ways to pump immediate life into the flaccid economy of many underdeveloped countries. The present review critically describes leading potential feedstocks available for biodiesel production based on a full life-cycle analysis which comprises major producer countries, important cultivation practices and major fatty acid compositions of the produced biodiesel. This article provides a comprehensive approach about the twenty leading plant sources which can contribute to enhance biodiesel production throughout the world along with their production methodologies, physical and chemical fuel quality parameters and analytical techniques for the assessment of the quality of the prepared biodiesel. Biodiesel has become further interesting in recent years because of its eco-friendly benefits and the fact that it is made from renewable and sustainable resources. A wide literature review was conducted and the major fatty acid composition of various vegetable oils was discussed as it significantly affects biodiesel properties. Lipids obtained from filamentous fungi, for example, Cunninghamella echinulata exhibit great promise for biofuel production. Finally, this review will be helpful in promoting the development of biodiesel by several countries not only by extending scientific research and knowledge but also through the introduction of policies and expressing reasons underlying these policies. Conclusion: This review explains the potential feedstocks for renewable production of biodiesel.

Abrupt urbanization and industrialization around the world resulted in elevated environmental pollution and depletion of natural energy resources. An eco-friendly and economical alternative for energy production is the need of an hour. This can be achieved by converting the waste material into energy. One such waste is lignocellulosic agricultural residues, produced in billions of tons every year all around the world, which can be converted into bioethanol. The main challenge in this bioconversion is the recalcitrant nature of lignocellulosic material. The removal of cementing material is lignin and to overcome the potential inhibitors produced during the disintegration of lignin is the challenging task for biotechnologist. This task can be achieved by a number of different methods but laccase is the most effective and eco-friendly method that can be used for effective removal of lignin along with the increase the accessibility of cellulose and bioethanol yield.

Helicid is a specific Chinese natural drug. Helicid, its congeners, and its derivatives exhibit pronounced biological activities, among which its hypnotic effects stand out. The well-documented sedation and analgesic activity and low side effects of helicid have drawn more and more attention from scientists. Moreover, its clinical success and intriguing mechanism of action have stimulated great interest in further modification of helicid for improving its hypnotic activity. The 4-formyl group has been a major target for structural derivatization aimed at either producing more potent compounds or overcoming drug disadvantages. Accordingly, numerous helicid derivatives have been prepared via molecular docking and hemisynthesis. Although neither systematic nor comprehensive, there are two excellent reviews on the distribution, sources, applications, synthesis, and pharmacological activity of helicid that have been published in Chinese. In the present review, we attempt to compile and discuss the key data available in the literature on the multiple biological activities of helicid derivatives. This compilation of 102 references may be helpful in understanding the diverse biological properties of helicid while providing insights into its mechanism of action. This may direct future research in the synthesis of new derivatives and the exploration of other biological activities.

The use of nerve agents as warfare and in terrorist acts has drawn much attention from the governments and societies. Such toxic organophosphorus compounds are listed in Chemical Weapons Convention as Schedule 1 chemicals. The discussion about the chemical identity of the elusive Novichok agents, more potent compounds than best known G- and V-Agents, which have been implicated in recent rumorous assassination plots, clearly demonstrating the importance of the matter. Furthermore, accidents with pesticides or misuse thereof have been a pressing issue in many countries. In this context, the continued development of novel cholinesterase reactivators, antidotes for organophosphorus poisoning, a rather restricted class of pharmaceutical substances, is warranted. Testing of novel candidates may require use of actual nerve agents. Nonetheless, only a few laboratories comply with the requirements for storing, possession and manipulation of such toxic chemicals. To overcome such limitations, nerve agents’ surrogates may be a useful alternative, as they undergo the same reaction with cholinesterases, yielding similar adducts, allowing assays with novel antidote candidates, among other applications.

Background: α-Aryl substituted nitroalkanes are important synthetic intermediates for the preparation of pharmaceutical molecules, natural products, and functional materials. Due to their scare existence in Nature, synthesis of these compounds has attracted the attention of synthetic and medicinal chemists, rendering α-arylation of nitroalkanes of an important research topic. This article summarizes the important advances of α- arylation of nitroalkanes since 1963. Results: After a brief introduction of the synthetic application and the reactions of nitroalkanes, this article reviewed the synthetic methods for the α-arylated aliphatic nitro compound. The amount of research on α-arylation of nitroalkanes using various arylation reagents and the discovery of elegant synthetic approaches towards such skeleton have been discussed. This review described these advances in two sections. One is the arylation of non-activated nitroalkanes, with an emphasis on the application of diverse arylation reagents; the other focuses on the arylation of activated nitroalkanes, including dinitroalkanes, trinitroalkanes, α-nitrosulfones, α-nitroesters, α-nitrotoluenes, and α-nitroketones. The synthetic application of these methods has also been presented in some cases. Conclusion: In this review, we described the progress of α-arylation of nitroalkanes. Although the immense amount of research on α-arylation of aliphatic nitro compounds has been achieved, many potential issues still need to be addressed, especially the asymmetric transformation and its wide application in organic synthesis.

The furanone structure, a significant group of heterocyclic compounds, is frequently found in natural products that are exhibiting striking pharmacological effects and a growing field of research. They have a wide spectrum of pharmaceutical activity: anticataract, anticancer, antibacterial, anti-inflammatory, anticonvulsant. This review article presents a summary of natural furanones, synthetic methods, and the biological effects of these important compounds. Solid-phase method, cross-coupling reactions, Maillard-type reaction, the cycloaddition of alcohol and phenyl nitrile oxide, and side-chain modifications are some types of reactions for the preparation of furanone derivatives. Methods of preparation and pharmacological activities of furanone skeletons that are discussed in this review article will help the medicinal chemists to design and execute novel procedures towards finding new drugs.