Academic literature on the topic 'GREEN SYNTHETIC PATHWAYS'

ContentsGreen Chemistry in the International ContextThe Concept of green ChemistryDefinition of green chemistry | Green chemistry: Why now? | The historical context of green chemistry | The emergence of green chemistryThe Content of Green ChemistryAreas of green chemistry | Preliminary remarks | Alternative feedstocks | Benign reagents/synthetic pathways | Synthetic transformations | Solvents/reaction conditionsGreen Chemistry in the International ContextIt has come to be recognized in recent years, that the science of chemistry is central to addressing the problems facing the environment. Through the utilization of the various subdisciplines of chemistry and the molecular sciences, there is an increasing appreciation that the emerging area of green chemistry1is needed in the design and attainment of sustainable development. A central driving force in this increasing awareness is that green chemistry accomplishes both economic and environmental goals simultaneously through the use of sound, fundamental scientific principles. Recently, a basic strategy has been proposed for implementing the relationships between industry and academia, and hence, funding of the research that constitutes the engine of economic advancement; it is what many schools of economics call the "triple bottom line" philosophy, meaning that an enterprise will be economically sustainable if the objectives of environmental protection, societal benefit, and market advantage are all satisfied2. Triple bottom line is a strong idea for evaluating the success of environmental technologies. It is clear that the best environmentally friendly technology or discovery will not impact on the market if it is not economically advantageous; in the same way, the market that ignores environmental needs and human involvement will not prosper. This is the challenge for the future of the chemical industry, its development being strongly linked to the extent to which environmental and human needs can be reconciled with new ideas in fundamental research. On the other hand, it should be easy to foresee that the success of environmentally friendly reactions, products, and processes will improve competitiveness within the chemical industry. If companies are able to meet the needs of society, people will influence their own governments to foster those industries attempting such environmental initiatives. Of course, fundamental research will play a central role in achieving these worthy objectives. What we call green chemistry may in fact embody some of the most advanced perspectives and opportunities in chemical sciences.It is for these reasons that the International Union of Pure and Applied Chemistry (IUPAC) has a central role to play in advancing and promoting the continuing emergence and impact of green chemistry. When we think about how IUPAC furthers chemistry throughout the world, it is useful to refer to IUPAC's Strategic Plan. This plan demonstrates the direct relevance of the mission of IUPAC to green chemistry, and explains why there is growing enthusiasm for the pursuit of this new area as an appropriate activity of a scientific Union. The IUPAC Strategic Plan outlines among other goals:IUPAC will serve as a scientific, international, nongovernmental body in objectively addressing global issues involving the chemical sciences. Where appropriate, IUPAC will represent the interests of chemistry in governmental and nongovernmental forums.IUPAC will provide tools (e.g., standardized nomenclature and methods) and forums to help advance international research in the chemical sciences.IUPAC will assist chemistry-related industry in its contributions to sustainable development, wealth creation, and improvement in the quality of life.IUPAC will facilitate the development of effective channels of communication in the international chemistry community.IUPAC will promote the service of chemistry to society in both developed and developing countries.IUPAC will utilize its global perspective to contribute toward the enhancement of education in chemistry and to advance the public understanding of chemistry and the scientific method.IUPAC will make special efforts to encourage the career development of young chemists.IUPAC will broaden the geographical base of the Union and ensure that its human capital is drawn from all segments of the world chemistry community.IUPAC will encourage worldwide dissemination of information about the activities of the Union.IUPAC will assure sound management of its resources to provide maximum value for the funds invested in the Union.Through the vehicle of green chemistry, IUPAC can engage and is engaging the international community in issues of global importance to the environment and to industry, through education of young and established scientists, the provision of technical tools, governmental engagement, communication to the public and scientific communities, and the pursuit of sustainable development. By virtue of its status as a leading and internationally representative scientific body, IUPAC is able to collaborate closely in furthering individual national efforts as well as those of multinational entities.An important example of such collaboration in the area of green chemistry is that of IUPAC with the Organization for the Economical Cooperation and Development (OECD) in the project on "Sustainable Chemistry", aimed at promoting increased awareness of the subject in the member countries. During a meeting of the Environment Directorate (Paris, 6 June 1999), it was proposed that United States and Italy co-lead the activity, and that implementation of five recommendations to the member countries be accorded the highest priority, namely:research and developmentawards and recognition for work on sustainable chemistryexchange of technical information related to sustainable chemistryguidance on activities and tools to support sustainable chemistry programssustainable chemistry educationThese recommendations were perceived to have socio-economic implications for worldwide implementation of sustainable chemistry. How IUPAC and, in particular, its Divisions can contribute to this effort is under discussion. IUPAC is recognized for its ability to act as the scientific counterpart to OECD for all recommendations and activities. Although the initiatives being developed by the OECD are aimed primarily at determining the role that national institutions can play in facilitating the implementation and impact of green chemistry, it is recognized that each of these initiatives also has an important scientific component. Whether it is developing criteria or providing technical assessment for awards and recognition, identifying appropriate scientific areas for educational incorporation, or providing scientific insight into the areas of need for fundamental research and development, IUPAC can play and is beginning to play an important role as an international scientific authority on green chemistry.Other multinational organizations including, among others, the United Nations, the European Union, and the Asian Pacific Economic Community, are now beginning to assess the role that they can play in promoting the implementation of green chemistry to meet environmental and economic goals simultaneously. As an alternative to the traditional regulatory framework often implemented as a unilateral strategy, multinational governmental organizations are discovering that green chemistry as a nonregulatory, science-based approach, provides opportunities for innovation and economic development that are compatible with sustainable development. In addition, individual nations have been extremely active in green chemistry and provide plentiful examples of the successful utilization of green chemistry technologies. There are rapidly growing activities in government, industry, and academia in the United States, Italy, the United Kingdom, the Netherlands, Spain, Germany, Japan, China, and many other countries in Europe and Asia, that testify to the importance of green chemistry to the future of the central science of chemistry around the world.Organizations and Commissions currently involved in programs in green chemistry at the national or international level include, for example:U.S. Environmental Protection Agency (EPA), with the "Green Chemistry Program" which involves, among others, the National Science Foundation, the American Chemical Society, and the Green Chemistry Institute;European Directorate for R&D (DG Research), which included the goals of sustainable chemistry in the actions and research of the European Fifth Framework Programme;Interuniversity Consortium "Chemistry for the Environment", which groups about 30 Italian universities interested in environmentally benign chemistry and funds their research groups;UK Royal Society of Chemistry, which promotes the concept of green chemistry through a "UK Green Chemistry Network" and the scientific journal Green Chemistry;UNIDO-ICS (International Centre for Science and High Technology of the United Nations Industrial Development Organization) which is developing a global program on sustainable chemistry focusing on catalysis and cleaner technologies with particular attention to developing and emerging countries (the program is also connected with UNIDO network of centers for cleaner production); andMonash University, which is the first organization in Australia to undertake a green chemistry program.Footnotes:1. The terminology "green chemistry" or "sustainable chemistry" is the subject of debate. The expressions are intended to convey the same or very similar meanings, but each has its supporters and detractors, since "green" is vividly evocative but may assume an unintended political connotation, whereas "sustainable" can be paraphrased as "chemistry for a sustainable environment", and may be perceived as a less focused and less incisive description of the discipline. Other terms have been proposed, such as "chemistry for the environment" but this juxtaposition of keywords already embraces many diversified fields involving the environment, and does not capture the economic and social implications of sustainability. The Working Party decided to adopt the term green chemistry for the purpose of this overview. This decision does not imply official IUPAC endorsement for the choice. In fact, the IUPAC Committee on Chemistry and Industry (COCI) favors, and will continue to use sustainable chemistry to describe the discipline.2. J. Elkington, < http://www.sustainability.co.uk/sustainability.htm

The search for economical, sustainable and practical pathways in synthetic science would contribute to improving resource efficiency, developing a recycling economy and driving new-type urbanization. Green synthesis has established firm ground providing the right green yardstick for development of a sustainable approach to bioactive high-added value molecules and drug discovery, and further development of sustainable manufacturing processes in the pharmaceutical industry toward a green resource efficient economy. In this study, the combination of FeCl3 and glycerol exhibits a versatile and high catalytic activity in the atom economical 1,6-conjugated addition of para-quinone methides derived from isatins with indoles using the right green yardstick. The sustainable pathway provides the preparation of bioactive indole-containing oxindoles in excellent yields with superior advantages, such as the ready availability, low price and environmentally benign character of iron catalysis, easy product separation, cheap and safe bio-renewable glycerol as a green solvent, and catalytic system recycling under mild conditions.

The dynamic growth in green organic synthetic methodologies for diverse heterocyclic scaffolds has substantially contributed to the field of medicinal chemistry over the last few decades. The use of hybrid metal nanocatalysts (NCs) is one such benign strategy for ensuring the advancement of modern synthetic chemistry by adhering to the principles of green chemistry, which call for a sustainable catalytic system that converts reacting species into profitable chemicals at a faster rate and tends to reduce waste generation. The metal nanoparticles (NPs) enhance the exposed surface area of the catalytic active sites, thereby making it easier for reactants and metal NCs to have an effective interaction. Several review articles have been published on the preparation of metal NCs and their uses for various catalytic heterocyclic transformations. This review will summarize different metal NCs for the efficient green synthesis of various O-heterocycles. Furthermore, the review will provide a concise overview of the role of metal NCs in the synthesis of O-heterocycles and will be extremely useful to researchers working on developing novel green and simple synthetic pathways to various O-heterocyclic-derived molecules.

Dinucleoside 5′,5′-polyphosphates (DNPs) are endogenous substances that play important intra- and extracellular roles in various biological processes, such as cell proliferation, regulation of enzymes, neurotransmission, platelet disaggregation and modulation of vascular tone. Various methodologies have been developed over the past fifty years to access these compounds, involving enzymatic processes or chemical procedures based either on P(III) or P(V) chemistry. Both solution-phase and solid-support strategies have been developed and are reported here. Recently, green chemistry approaches have emerged, offering attracting alternatives. This review outlines the main synthetic pathways for the preparation of dinucleoside 5′,5′-polyphosphates, focusing on pharmacologically relevant compounds, and highlighting recent advances.

Perimidines are available in an assortment of drugs and general use industrial structures and perimidines are also significant primary theme because of their extraordinary method of physiological activity. Thus the underlying significance of perimidine moiety has evoked a lot of interest in the field of natural blend and compound science to build up some better than ever amalgamation of this atomic skeleton. In this review, we have depicted a modern outline on the new advances in the different manufactured approaches of perimidine. The review covers the essential applied and down to earth synergist blend like, green methodologies, metal catalysed responses, microwave illumination, grinding and so forth which are critical for developing perimidine skeleton. This review will fulfill the assumptions for peruses who are keen on the advancement of the field and searching for an update. It will animate analysts to grow new and innovative manufactured admittance to this heterocyclic framework, which will be instrumental in the headway of perimidine science. This review provides an overview of various synthetic methodologies for the synthesis of a wide range of perimidine derivatives with applications in material chemistry, drug discovery, polymer chemistry, photo sensors, dye chemistry, and other fields.

Background: Nanoreactors technology represents a promising tool for efficient and selective organic synthesis typically under “green” and sustainable reaction conditions. These structures with generating a confined reaction environment to accommodate that both reactants and catalysts can change the reaction pathways and induce new activities and selectivities. Objective: The paper reviews literature examples in which nanoreactors were employed in various types of organic and metal catalyzed reactions including multicomponent reactions, palladium-catalyzed coupling reactions, olefin metathesis, aza-Cope rearrangement, allylic alcohol isomerization, cyclization reactions, ring opening reactions, halogenation reactions, hydrolysis reactions, hydroformylation reactions, cascade reactions, addition reactions, oxidation reactions and reduction reactions. The reactions' survey is accompanied with the explanation of structure and performance of nanoreactors that are applied there. Conclusion: The availability of comprehensive information about the role of nanoreactors technology in green organic synthesis and investigation of different aspects of them such as their structures, mechanisms and synthetic utility can assist researchers in designing the greener approaches in organic synthesis.

Dimethindene is a selective histamine H1 antagonist and is commercially available as a racemate. Upon analyzing the synthetic pathways currently available for the industrial preparation of dimethindene, we set up a sustainable approach for the synthesis of this drug, switching from petroleum-based volatile organic compounds (VOCs) to eco-friendly solvents, such as 2-methyltetrahydrofuran (2-MeTHF) and cyclopentyl methyl ether (CPME) belonging to classes 3 and 2, respectively. Beyond decreasing the environmental impact of the synthesis (E-factor: 24.1–54.9 with VOCs; 12.2–22.1 with 2-MeTHF or CPME), this switch also improved the overall yield of the process (from 10% with VOCs to 21–22% with 2-MeTHF or CPME) and remarkably simplified the manual operations, working under milder conditions. Typical metrics applied at the first and second pass, according to the CHEM21 metrics toolkit, were also calculated for the whole synthetic procedure of dimethindene, and the results were compared with those of the classical procedure.

Many scientists are working hard to find green alternatives to classical synthetic methods. Today, state-of-the-art ultrasonic and grinding techniques already drive the production of organic compounds on an industrial scale. The physicochemical and chemical behavior of cyclodextrins often differs from the typical properties of classic organic compounds and carbohydrates. The usually poor solubility and complexing properties of cyclodextrins can require special techniques. By eliminating or reducing the amount of solvent needed, green alternatives can reform classical synthetic methods, making them attractive for environmentally friendly production and the circular economy. The lack of energy-intensive synthetic and purification steps could transform currently inefficient processes into feasible methods. Mechanochemical reaction mechanisms are generally different from normal solution-chemistry mechanisms. The absence of a solvent and the presence of very high local temperatures for microseconds facilitate the synthesis of cyclodextrin derivatives that are impossible or difficult to produce under classical solution-chemistry conditions. Although mechanochemistry does not provide a general solution to all problems, several good examples show that this new technology can open up efficient synthetic pathways.

Electrolysis in microemulsions is a promising approach for environmentally friendly chemical synthetic methods of the future. Employing microemulsions instead of organic solvents for electrosynthesis has the advantages of lower toxicity and cost, high dissolving power for reactants and mediators of unlike solubility, enhancement of reaction rates by controlling the reduction potentials of mediators, possible reaction pathway control, and recycling of microemulsion components. This paper reviews recent progress in using microemulsions for direct and mediated electrosynthesis, including formation of carbon­carbon bonds. Rates of mediated reactions can be controlled by manipulating microemulsion composition. Examples are presented, in which reaction pathways of direct and mediated electrolyses can be controlled with microemulsions to give desired products in high yields. Such control has been demonstrated with dissolved and surface-bound mediators. For a covalently linked scaffold of poly(l-lysine) and cobalt corrin vitamin B12 hexacarboxylate attached to graphite, catalytic turnover rate for reduction of 1,2-dibromocylcohexane was optimized by optimizing microemulsion composition.

Carbon dots (CDs) are semiconductor materials with sizes ranging from 2 to 10 nm. Among these CDs, nickel CDs (Ni@CDs) materials have piqued researchers' curiosity in the past years due to their specific properties, such as strong catalytic activity, good stability, great hydrophilicity, and high oxidation states. Several synthetic pathways exist for the synthesis of Ni@CDs, such as hydrothermal method, microwave irradiation, green synthesis, pyrolytic decomposition, precipitation method, and electrochemical route. These Ni@CDs have shown application in charge transfer, excellent thermodynamic stability, luminescent properties, high chemical and photo-stability, opto-electronic devices, catalysis, sensing, and drug delivery. In this review, various synthetic methods had been explored extensively along with their numerous applications.

The principal goal of basic research in chemical synthesis is the development of efficient tools for functional group transformations and for the assembly of building blocks during the construction of molecules with increasing complexity. Traditionally, new approaches in this area have focused on the quest for new reaction pathways, reagents, or catalysts. Comparably less effort has been devoted to utilize the reaction medium as a strategic parameter, although the use of solvents is often crucial in synthetically useful transformations. The first choice for a solvent during the development of a synthetic procedure is usually an organic liquid, which is selected on the basis of its protic or aprotic nature, its polarity, and the temperature range in which the reaction is expected to proceed. Once the desired transformation is achieved, yield and selectivity are further optimized in the given medium by variation of temperature, concentration, and related process parameters. At the end of the reaction, the solvent must be removed quantitatively from the product using conventional workup techniques like aqueous extraction, distillation, or chromatography. If the synthetic procedure becomes part of a large-scale application, the solvent can sometimes be recycled, but at least parts of it will ultimately end up in the waste stream of the process. Increasing efforts to develop chemical processes with minimized ecological impact and to reduce the emission of potentially hazardous or toxic organic chemicals have stimulated a rapidly growing interest to provide alternatives to this classical approach of synthesis in solution. At the same time, researchers have started to realize that the design and utilization of multifunctional reaction media can add a new dimension to the development of synthetic chemistry. In particular, efficient protocols for phase separations and recovery of reagents and catalysts are urgently required to provide innovative flow schemes for environmentally benign processes or for high-throughput screening procedures. Fluorous liquid phases and supercritical carbon dioxide (sc CO2) have received particular attention among the various reaction media that are discussed as alternatives to classical organic solvents. The aim of this chapter is to compare these two media directly and to critically evaluate their potential for synthetic organic chemistry.

Cancer is portrayed as a group of disease characterized by alteration in the normal regulation of cell growth by the successive acquisition of genetic, somatic, and epigenetic alteration. Synthetic drugs are single targets while natural products are multi-targeted to prevent cancer. NF-κB is persistently active in a number of disease states, including cancer, and therefore has a critical role in cancer development and progression. It also provides a mechanistic link between inflammation and cancer and is a major controlling factor resistant to apoptosis in both pre-neoplastic and malignant cells. Importantly, NF-kB and the signaling pathways that mediate its activation have become attractive targets for the development of new chemopreventive and chemotherapeutic approaches. Natural antioxidants have been shown to possess chemopreventive and chemotherapeutic potential via targeting NF-κB signaling, among which tea polyphenols have been studied extensively. In this chapter, the authors summarize the regulation of NF-κB pathway by green tea polyphenols in different cancer types.

The morpholine ring is considered the most preferred and versatile heterocylic ring in medicinal chemistry due to its distinctive mechanistic activities that give it various biological activities. The eminence of the morpholine ring to modulate the pharmacokinetic properties of the compound, further makes it a fundamental pharmacophore in developing lead molecules. Multi-drug resistance in cancer leads to discovering selective and potent chemotherapeutic agents. Researchers are designing and synthesizing morpholine derivatives as potential anticancer drugs those act by targeting various signaling pathways driven by various protein kinases in the cell, i.e. Ras-Raf-MEK-ERK (ERK) and PI3K/Akt/mTOR, thereby inhibiting cell proliferation and growth. The potency of natural and synthetic derivatives of morpholine makes it a drug of choice for cancer treatment. Many of the morpholine containing anticancer drugs are under clinical trials. Hence, morpholine ring synthesis also becomes a central target for various scientists using green synthesis by straightforward one-step methods. A substantial literature is available on synthetic techniques of morpholine and substituted morpholine. The present chapter updates diverse new synthetic strategies of the morpholine ring and morpholine derivatives with potent anticancer activity. The chapter will also highlight the clinical data of morpholine derivatives with anticancer activity and mechanism of action. The latest information on novel anticancer morpholine derivatives with structural activity relationship (SAR) is also included. This chapter provides information about the necessary structural modifications required in drugs' chemical structure and contribute to the anticancer drug discovery program.

Nanoparticles (NPs) have become a hot research material in many fields, such as catalysis, sensing, clinical diagnosis, medical treatment, antimicrobial agents, and environmental remediation, due to their small size, high surface area, high reactivity, and unique optical, electrical, and thermodynamic properties. The type, morphology, size, and surface function modification of NPs determine their performance and application scope. The development of green, simple, and controllable NP synthesis methods is an important research direction at present. The biosynthesis of NPs is a kind of green synthesis method that uses organisms or biomolecules to reduce NP precursors. The reaction conditions are mild, the energy consumption is low, and there is no need for expensive equipment or harmful chemicals. It has been developed into an important branch of nanobiotic technology. This chapter summarizes the latest progress in the synthesis of NPs from different plant tissue extracts. It also summarizes the biosynthesis mechanism and application of NPs, analyzes the main problems faced by the biosynthesis method, and prospects its future research direction.

The formation of carbon-carbon/carbon-heteroatom bonds by oxidative transformations is a hotly debated topic in chemistry. K2S2O8 has emerged as a cost-effective inorganic oxidant for a wide range of oxidative reactions in this setting. This book chapter covers oxidative reactions facilitated by K2S2O8 in the absence of a metal catalyst in detail. Organic chemists may find this book chapter valuable in formulating the mechanistic pathways involving the sulphate radical anion, as well as in the quick and environmentally friendly synthesis of novel chemical species.

The precursors of nanomaterials can be transformed into nanomaterials in plants. This chapter introduces plants as hosts for nanomaterial synthesis. Although the synthesis of nanomaterials by this method cannot be obtained in large quantities, the existence of nanomaterials in plants will have a certain impact on the growth of plants. This technique may not be useful in the synthesis of nanomaterials, but it has potential applications in agriculture.

In order to ensure the needs of survival and reproduction, plants have formed various, diverse, multi-dimensional, and multi-scale fine and subtle configurations for millions of years, which provides rich inspiration for scientific research in many fields today. Research on morphology genetic material converts natural biological components into target materials by directly using biological structures as templates and selecting appropriate physicochemical methods while maintaining the fine-graded structure of the template. It can be used to prepare new functional materials with a biological finely-graded structure. This section describes methods for preparing functional materials with biological structures using morphology genetic material research ideas. In this chapter, we briefly introduce the structure of residual materials prepared by using several typical plant structures as templates, and discuss the related functional performance of materials with different structural characteristics.

The synthesis of carotenoids has been studied toward enhancing the production of ketocarotenoids, since fish and crustaceans raised by aquaculture require astaxanthin and other ketocaroteinoids in their feed for desirable pigmentation. Notable progress has been made in attaining the goals of determining improved conditions for ketocarotenoid production in Haematococcus pluvialis and in elucidating the carotenoid biosynthetic pathway. For production of astaxanthin a number of strains of the green alga Haematococcus were evaluated, a strain CCAG was found to be optimal for photoautotrophic growth. Of four mutants, selected for enhanced carotenoid production, two hold considerable promise because caroteinoid accumulation occurs without encystment. The biosynthetic pathway of carotenoids was elucidated in photosynthetic organisms by characterizing novel genes encoding carotenoid enzymes and by examining the function of these enzymes in a bacterial complementation system. Two cyclases (b- and e-) were cloned that are at a critical branch point in the pathway. One branch leads to the formation of b-carotene and zeaxanthin and astaxanthin, and the other to the production of a-carotene and lutein. Cyclization of both endgroups of lycopene to yield b-carotene was shown to be catalyzed by a single gene product, b-lycopene cyclase in cyanobacteria and plants. The formation of a-carotene was found to require the e-cyclase gene product in addition to the b-cyclase. By cloning a b-hydroxylase gene we showed that a single gene product forms zeaxanthin by hydroxylatin of both b-carotene rings. It is expected that a second hydroxylase is required in the synthesis of astaxanthin, since canthaxanthin rather than zeaxanthin is the precursor. Evidence, from inhibitor studies, suggests that astaxanthin is formed from canthaxanthin and that b-carotene is a major precursor. Feasibility studies with the photobioreactors have shown that a two-stage system is the most practical, where Haematococcus cultures are first grown to high cell density and are then switched to high light for maximal astaxanthin production. The basic knowledge and molecular tools generated from this study will significantly enhance Haematococcus as a viable model for enhanced astaxanthin production.