Current Organic Chemistry

The recent interest in the synthesis of a wide range of functionalized biologically active molecules was driven by the ever growing demands of the pharmaceutical industry [1-3]. The synthesis of complex molecules with different active pharmacophores has been achieved by adopting tailored synthetic approaches. The traditional methods for the synthesis of biologically active molecules have several drawbacks, including multi-step approaches, low isolated yields, longer reaction times, tedious purification procedures, employing toxic catalysts and reagents, and harsh reaction conditions [4-6]. To avoid such drawbacks, different modern synthetic strategies have been recently developed for the synthesis of bio-active molecules. Among these, one-pot multicomponent reactions, C-H activation reactions, nanocatalysis, mechanochemical reactions using ball milling, microwave assisted synthesis, visible light assisted photocatalytic reactions, and sonochemical organic synthesis have attracted great attention for clean organic synthesis. The fast and growing developments in this field are overwhelming, and call for special efforts to collect relevant information for the benefit of academics and individuals involved in the pharmaceutical industry. This thematic issue is dedicated to highlighting the modern progress in developing various strategies for the synthesis of bio-active molecules, with special emphasis on greener synthesis routes [7-12]. The present issue includes eight review articles contributed by eminent research groups involved in this prominent organic chemistry field, which provide up-to-date developments in selected topics. In summary: The first contribution titled ‘Microwave: A Green contrivance for the Synthesis of N-Heterocyclic Compounds’ by Lambat et al. highlights the microwave mediated catalytic reactions used for the synthesis of a diversity of N-heterocycles by multi-component reactions (MCRs) and a variety of miscellaneous reactions. The review also addresses some aspects of the use of nanoparticles for a diversity of applications in microwave chemistry [13]. The second contribution titled ‘Methods and Strategies Used in Green Chemistry: A Review’ by Pottoo et al. summarizes the literature associated with the development of various compounds and greener techniques such as ultrasound-assisted method, microwave-assisted method, green solvent reactions, solvent free reactions, biomolecules and nano-formulations as new safe approaches [14]. The third contribution, titled ‘Review on Synthesis of Bio-Active Coumarin-Fused Heterocyclic Molecules’ by Banerjee et al., describes the various methods for synthesizing different classes of coumarin-fused heterocyclic molecules and their applications in chemical, optical, pharmaceutical and other useful applications [15]. The fourth contribution titled ‘CO Surrogates: A green Alternative in Palladium Catalyzed CO Gas Free Carbonylation reactions’ by Ahmed Abdala and Lambat et al. addresses the recent developments in palladium-catalyzed carbonyl insertions without the direct use of gaseous CO [16]. The fifth contribution, titled ‘Recent Advances in On-Water Multicomponent Synthesis of Coumarin Derivatives’ by Penta et al. addresses the one pot multicomponent synthesis of structurally diverse coumarin scaffolds in water as an efficient and green medium [17]. The sixth contribution titled ‘Palladium-Catalyzed Cascade Reactions for Annulative π-Extension of Indoles to Carbazoles through C-H Bond Activation’ by Jana et al. is concerned with the survey of recent literature on palladium-catalyzed π-extension of indole to carbazole moiety through C-H bond activation [18]. The seventh contribution titled ‘Modern Progress in Iron-Catalyzed Reactions towards the Synthesis of Bioactive Five- and Six- Membered Heterocycles’ by Adak et al. discusses the catalytic applicability of iron and its derivatives for various organic transformations and the synthesis of biologically active five and six membered heterocyclic compounds [19]. The last contribution, titled ‘Green Approaches for the Synthesis of Indole Derivatives and their Pharmaceutical Applications: Last Ten Years Developments’ by Das et al. discusses the various synthetic methods for the preparation of structurally diverse indole scaffolds using green chemistry and their pharmaceutical relevance [20]. As Guest Editors, we would like to appreciate all the authors for their valuable contributions and all the referees for their excellent work in reviewing the submitted manuscripts. We are also grateful to the Editor-in-Chief Prof. György Keglevich and the Editorial Manager Ms. Sanober Maqbool for their kind support in preparing this Thematic Issue.

Synthetic peptides and amino acids are important sources for developing new drugs, because they have low toxicity and specificity, are less prone to side effects, and have the advantage of being low-cost. However, peptides and amino acids have some limitations from the pharmacological point of view, because of their low residence time in the body and low effective concentration at the site of action, which is mainly due to factors such as susceptibility to enzymatic degradation, rapid elimination, and low ability to penetrate across membranes [1-3]. The bioavailability and bio-distribution of peptides and amino acids in the body can be improved by chemical modification. In this context, chemical synthesis can allow obtaining linear, cyclic, polyvalent, and chimeric peptides, among others. In addition, peptide biological activity can be enhanced by incorporating unnatural amino acids, steroids, hormones, organometallic compounds, carbohydrates, lipids, antibiotics, organic compounds, inorganic compounds, etc. This functionalization can be performed directly on the peptide or on the amino acids that generate the building blocks that are conjugated with these molecules, which can then be used as precursors in order to obtain the peptides and proteins [4-8]. This thematic issue is a review of the synthetic approaches developed over the last few years for enhancing the biological activity of promising peptide sequences. Researchers with recognized expertise in organic synthesis as a tool for the development of molecules for biomedical applications participated in preparing the issue. A brief description of each of these contributions is given below. In the manuscript entitled “The Role of αvβ6 Integrin Binding Molecules in the Diagnosis and Treatment of Cancer”, Dr. Urquiza, et al. describe the importance of integrin in cancer treatment and discuss peptides, recombinant proteins, non-peptide molecules, and αvβ6- antibodies that specifically bind to αvβ6-integrin. In addition, the biological properties and possible uses of these molecules in cancer imaging and therapy are described since the αvβ6-integrin is over-expressed in most tumor cells [9]. In the manuscript entitled “Resorcin[4]arenes: Generalities and Their Role in the Modification and Detection of Amino Acids”, Dr. Maldonado, et al. present a valuable review of the properties and characteristics of resorcin[4]arenes, as well as the main synthetic routes used to form amino acid-conjugated macrocycles that could have multiple applications in the pharmaceutical sciences, engineering, and medicine [10]. In the manuscript entitled “Ferrocene and organotin (IV) conjugates containing amino acids and peptides: a promissory tool for searching for new therapeutic and diagnostic tools”, Dr. Farfan, et al. describe the synthesis strategies used for the preparation of amino acids and peptides containing ferrocene or organotin (IV) derivatives. In addition, the antibacterial and/or anti-cancer properties of these organometallic compounds are summarized [11]. In the manuscript entitled “Designing short peptides: a Sisyphean task”, Dr. Rivera, et al. review the synthetic approaches and strategies used to design short peptides, highlighting the achievements, limitations, and advantages of each method. The advantage of short peptides lies in their stability, ease of production, safety, and low cost, as well as their biomedical and industrial applications [12]. In the manuscript entitled “Development of strategies for glycopeptide synthesis: an overview on the glycosidic linkage”, Dr. Garcia, et al. present a review of the chemical synthesis of glycoconjugates in solution and/or solid phase. Several methods for the synthesis of glycosylated amino acid derivatives and/or glycopeptides and their use as drugs to mitigate the impact of microbial resistance and/or cancer are described [13]. In the manuscript entitled “Electrochemical Detection of Neurotransmitters in the Brain and Other Molecules with Biological Activity on the Nervous System”, Dr. Bustos, et al. describe the electrochemical techniques used for in vitro or in vivo detection of neurotransmitters and other molecules with biological activity at the level of the central nervous system, as a contribution to the diagnosis of neurological diseases [14]. In the manuscript entitled “Bio-organometallic Peptide Conjugates: Recent Advances in their Synthesis and Prospects for Biomedical Application”, Dr. Guzman, et al. review synthetic strategies for obtaining organometallic peptides and amino acids containing ferrocene, rutenocene, cimantrene, or osmocene. The authors describe SPPS and/or click chemistry-based methods used for obtaining organometallic compounds that could be used to develop a new generation of antimicrobial and chemotherapeutic drugs [15]. Finally, as Guest Editor of this issue, I would like to express my thanks to all the authors for their high-quality manuscripts and to the reviewers for their time and effort in providing constructive critiques in order to guarantee the excellence of this issue. I am also thankful for the logistical assistance of Ms. Sanober Maqbool, Editorial Manager, during the submission and review procedures.

This Special Issue covers the hot topics on recent synthetic interest in halogen and related chemistry as well as the unique characteristics of halogen compounds. The excellent reviews by the experts and eminent researchers engaged in the recent advances, i.e., preparations, reactions, and mechanistic studies of unique organohalogen compounds, halogen bond interaction as the catalysis, and halogen-controlled unique reactions for synthesizing useful organic molecules, such as pharmaceutical compounds and organic materials, are provided in this Special Issue.

Carbon-carbon and carbon-heteroatom bond-forming reactions are the most important tools for the syntheses of structurally diverse molecular entities [1]. Various drug molecules, bioactive heterocycles, agrochemicals, dyes, pigments, pharmaceuticals, vitamins, hormones and other useful organic substances are being synthesized via these carbon-carbon and carbon-heteroatom bond-formation strategies. Therefore, under these environmentally conscious days, constant efforts have been made to design new methods or modify existing protocols for such bond-forming reactions to make them sustainable [2, 3]. As a result, the last decade has shown a tremendous outburst to carry out carbon-carbon and carbon-heteroatom bond-forming reactions under environmentally benign and sustainable conditions [4-10]. The thematic issue ‘Carbon-Carbon and Carbon-Heteroatom Bond- Forming Reactions Under Greener Conditions’ is aimed to highlight some of the recent developments In carbon-carbon and carbon-heteroatom bond forming reactions with special emphasis on greener aspects. The first part of this thematic issue, i.e., part-1A included five significant review articles [11-15]. The present part of this thematic issue, i.e., part-1B is composed of three valuable review articles contributed by the eminent research groups working on this fascinating field of organic chemistry. This part of the special thematic issue offers up-to-date literature on the following three selected topics: The first contribution of this part of the thematic issue titled ‘Green Chemistry Approaches to the Synthesis of Coumarin Derivatives’ by Molnar et al., describes various green synthetic approaches for the synthesis of diverse coumarin derivatives [16]. The second contribution, titled ‘Construction of Carbon-Carbon and Carbon-Heteroatom Bonds: Enabled by Visible Light’ by Mondal and Mukhopadhyay, summarizes the literature associated with the recent advancements on green visible lightmediated carbon-carbon and carbon-heteroatom bond-forming reactions [17]. In the last contribution titled ‘Formation of Carbon-Carbon Bonds Mediated by Hypervalent Iodine Reagents Under Metalfree Conditions’, Prof. Du and his research group highlight the recent advancement in the construction of carbon-carbon bonds utilizing hypervalent iodine reagents under metal-free condition [18]. I am grateful to all the contributors for their valuable efforts to organize this part of the special thematic issue for Current Organic Chemistry (COC). I am very much thankful to the senior journal manager and the entire editorial team of Current Organic Chemistry, specially Ms. Sanober Maqbool and Ms. Nuzhat Gul, for their continued support. No words are sufficient to express my gratitude to Prof. (Dr.) Gyorgy Keglevich (Editor-in-Chief) for his unconditional help and encouragement. I am also thankful to the respective reviewers for their efforts and suggestions to improve the quality of this special thematic issue.

Carbon-Carbon and Carbon-Heteroatom Bond-forming Reactions under Greener Conditions-Part 1A

The Chemistry of Allenes

Nowadays, environmental pollution/deterioration and greenhouse effect are becoming increasingly prominent, primarily due to the dependence and overuse of fossil source [1, 2]. As a result, the development of green and sustainable approaches has become a particularly important theme in recent years [3-5]. Organic synthesis is a versatile tool in the design and creation of desirable scaffolding molecules, while the processes of which typically involves toxic and non-renewable starting materials as well as the formation of waste or by-products [6]. Biomass, on the other hand, is considered as the most abundant organic carbon resource for producing liquid fuels and value-added chemicals through an array of cascade chemocatalytic reactions [7- 10]. The exploration of robust and green technologies is accordingly being deemed to be one of the vital and promising means for biomass valorization and relevant organic transformations. This thematic issue thereby aims to survey the development of green technologies for catalytic upgrading of biomass feedstocks, and provides a glimpse into successful examples in this research area. Five eminent research groups in the field of biomass valorization have kindly accepted our invitation to participate in this special issue by providing an overview on the recent advances on selected topics briefly listed as follows: Dr. Chen et al. in “Lignin Reactions and Structural Alternations under Typical Biomass Pretreatment Methods” introduce typical pretreatment methods such as hydrothermal pretreatment, alkaline pretreatment, biodegradation, and oxidative pretreatment, with their corresponding impacts on the lignin structures and reactions [11]. Dr. Lin et al. in “Chemoselective Hydrogenation of Biomass-derived 5-hydroxymethylfurfural into Furanyl Diols” comprehensively summarize the studies on the chemoselective hydrogenation of 5-hydroxymethylfurfural into furanyl diols in terms of different H-donors, including molecular H2, alcohols, formic acid and other alternative H-donors, and also provide future research direction on the production of furanyl diols [12]. Dr. Li et al. in “Alcohol-mediated Reduction of Biomass-derived Furanic Aldehydes via Catalytic Hydrogen Transfer” depict alcohol-mediated reduction of biomass-derived furanic aldehydes via catalytic hydrogen transfer, also with attention on the representative reaction mechanisms and selective control of product distribution [13]. Dr. Liu et al. in “Catalytic Hydrogenolysis of Biomass-derived Polyhydric Compounds to C2–C3 Small-molecule Polyols: A review” describe the catalysts and catalysis for selective hydrogenolysis of these polyhydric compounds to C2–C3 polyols, and outline the reaction pathways with the state-of-the-art technologies for the target polyol formation based on the C3, C5, and C6 polyhydric alcohol hydrogenolysis [14]. Dr. Yang et al. in “Chemo-catalytic Esterification and Transesterification over Organic Polymer-based Catalysts for Biodiesel Synthesis” discuss catalytic valorization of sustainable feedstocks into biodiesel via transesterification and esterification reactions mediated by functionalized organic polymers-based catalysts, with special emphasis on the synthetic routes to the versatile organic polymers-based catalytic materials [15]. As Guest Editors, we would like to appreciate all the authors for their valuable contributions and all the referees for their excellent work in reviewing the submitted manuscripts. We are also grateful to the Editor-in-Chief Prof. György Keglevich and the editorial manager Ms. Sanober Maqbool for their kind support in preparing this thematic issue.

Waste-to-valuable products are being considered as one of the best solutions to convert the waste biomass into green and environment-friendly products. The wide utilization of waste biomass as a potential source of fuels, power, recycled materials, valuable chemicals are well recognized globally. The waste driven fuels are used in all sectors of society for production of electricity, transport fuel, heating and cooling source, and for industrial processes. These fuels not only solve the waste disposal issues but also generate enormous economic and environmental benefits. They are promising alternatives due to their renewable, sustainable and eco-friendly features. However, there are multiple challenges in conversion and efficient utilization of waste biomass into sustainable energy and fuels [1]. The purpose of the special issue, titled “Waste Biomass Utilization for Value-added Green Products” is to focus on the best possible ways to convert the waste biomass into value added and renewable products with an ambition to highlight the recent trends targeting the challenges and opportunities in this area. Renowned researchers have accepted our invitation to contribute their articles on the below subtopics; Conversion/Utilization of Waste Biomass Feedstocks into Fuels: The aspects of discovery and utilization of different waste biomass feedstocks for generation of various fuels. The examples of such waste biomass to fuels systems include the bioalcohols, biodiesel, biogas, biohydrogen, and pyrolysis oils [2, 3]. The issue will cover a wide range of feedstock and conventional and new production methods including the challenges and prospects. In the last few decades, due to the everincreasing exploitation of fossil fuels, there is a significant emphasis and demand on exploring and developing alternative, costeffective, and non-food feedstocks or waste biomass sources for producing fuels and value-added products [4]. Micro-Algae and Macro-Algae Based Biofuels: In the last few decades, there has been tremendous research on the utilization of micro and macro algae for biofuels production and increasing the process efficiency and quality of the products [5]. Despite all these efforts and investment, there remain many challenges and scope for improvement in this area before potential commercialization of this technology worldwide. Multiple benefits are sought through these processes including biowaste treatment, production of clean fuels and CO2 capturing for huge environmental and economic benefits. Contributions under this subtopic would be preferred covering both the scientific and engineering aspects of algae biofuels. Development of Advanced Catalysts for Biofuels: The role of catalysts is critical not only in the conversion process of biofuels systems but also making the overall process more efficient, less energy intensive and economically feasible. However, the primary challenge with the use of catalysts is huge cost. Recently, waste biomass-based catalysts such as biochar and natural minerals like natural zeolite are utilized instead of costly commercial catalysts [6]. Therefore, this subtopic would cover how such cheap and effective catalysts could be developed for various biofuels systems such as transesterification (biodiesel), anaerobic digestion (biogas), fermentation (bio-alcohols) and bio-hydrogen [7]. State-of-the-art Cost-Effective Bioenergy Production Technologies: This subtopic would cover the state-of-the-art and costeffective bioenergy production technologies such as pyrolysis, supercritical water reforming, gasification, anaerobic digestion, torrefaction, and liquid phase processing [8]. Currently, one of the most limiting factors of bioenergy production technologies is the high capital/ operational cost or low profitability. New ideas and paradigm will be gathered to contribute solving this issue through this special issue. A primary emphasis would be given to such contributions which would cover the scientific aspects of process and products chemistry. Use of Waste and Non-profitable Natural Resources for Optimization of Biofuel Production: This subtopic would cover the utilization of waste and non-profitable natural resources such as lands, water, and biochar, natural minerals in optimizing the first and second generation biofuels such as bioalcohols (ethanol or methanol), biomethanation and biodiesel. Life Cycle Assessment (LCA) of Value-Added Green Products: This subtopic would cover the aspects of both biomass waste utilization and value-added green products in the form of fuels and energy [8,9]. The established or new models of LCA should be used for detailed technical, economic and environmental aspects of these processes and products, crucial before moving towards commercialization. In addition, the engineering design for feedstock processing and biofuel production plants would be covered under this subtopic. Integration of Waste to Energy Technologies: This subtopic would cover the various waste to energy and waste-based biorefineries systems in an integrated way. The ultimate goal is to achieve more sustainable and environmentally friendly systems and products. The examples of such systems include the organic waste biorefinery, agricultural and forestry residues biorefinery [10]. Contributors are encouraged to cover the various sources of municipal and industrial waste which could be potentially utilized for energy, fuels, heat, and chemicals production. As Guest Editors we would like to thank all the authors for their precious contributions and all the reviewers for their excellent work in evaluating the submitted manuscripts. We also wish to thank the Editor in Chief, Prof. György Keglevich and the Editorial Manager Ms. Sanober Maqbool for their kind support in preparing this Special Issue.

In the last few decades, catalyzed organic and bioorganic reactions have attracted much attention in chemical and pharmaceutical researches [1, 2]. Recently, the design of novel catalysts and enzymes is in much demand to circumvent certain intractable synthetic problems [3-6]. In this light, the modeling of catalytic procedures seems to be necessary and also important in the synthesis of emerging classes of organic compounds that are becoming the targets of molecular and biomedical researches [7-10]. Strictly speaking, the combination of computational approaches with experimental methods to model and interpret the mechanistic features of catalytic and enzymatic organic reactions provides more detailed information about the structure, bonding, stereochemistry and spectroscopic properties of compounds through the reaction path and consequently, leads to the new opportunities for production of novel chemicals and discovery of useful drugs [10-11]. In this context, the main goal of this thematic issue is to present comprehensive joint experimental and computational researches set in the field of catalytic organic synthesis and their rational mechanistical underpinning and the conjunction of experimental features of catalytic and enzymatic reactions with computational approaches will be covered. This thematic issue contains 3 reviews, written by highly knowledgeable teams with tremendous amount of experience in the field of computational organic chemistry, which are discussed as follows: The first article of this special issue by Laura Orian and her coworkers from the University of Padova describes the essential synthetic and reactivity aspects of organoselenides in a rational combination with the results of computational studies. In this line, reactivity of the Se-Se bond and the redox properties of selenium are discussed to produce diselenides compounds for the catalysis of many organic reactions and along with its enzymatic application as glutathione peroxidase, inspiring novel elements for rational catalyst, enzymes and drug design. The second review is provided by Ana María Mendoza-Wilson and her colleague on chemical structure and reactivity of procyanidins. Clearly speaking, in this review, the recent advances of experimental and computational studies on the potential of procyanidins as metalloproteinases inhibitors were investigated. In the last review article of this special issue by Tayebeh Hosseinnejad and Majid M. Heravi and their co-worker, Hantzsch dihydropyridines synthesis and their biological activities and also their applications in asymmetric transfer hydrogenation are investigated from the combined experimental and computational viewpoints. As a result, the thematic issue contains the reviews of emerging and cutting edge researches in the field of computational chemistry and modeling and hopefully attracts substantial attentions and stirs up the interest of readers in the related research community. Finally, I would like to acknowledge all the contributing authors, reviewers and the Editorial Office for their consistent efforts in bringing out this special issue.

Solid Phase Organic Synthesis (SPOS) was first introduced for peptide synthesis and is pioneered by R. B. Merrifield, which later earned him a Nobel Prize in Chemistry in 1984 [1, 2]. The solid-phase synthesis carries many advantages over classical solution-phase synthetic methods which may include purification of products by simple filtration of the polymer matrix [3], automatability [4], easy handling, low moisture susceptibility [5], minimum side reaction, polymerization-free due to site-isolation of polymer beads [6] and recyclability of the polymer matrix for repeated useage [7, 8]; thereby adding the ‘green’ credentials of the whole processes. Earlier, SPOS mainly refers to a multi-step organic synthesis using a polymer-bound reagent. However, these days, the single step organic synthesis using polymer and/ or other solid catalysts/ reagents is also included in SPOS domain. In recent years, polymer-bound reagents/ catalysts have received major attention from industry and academia mainly due to their easy handling, separation, and reusability [9-12]. In addition, as polymeric reagents/catalyst can be recycled and reused, they can be used in an excess amount to drive the reaction faster. In this special issue, different reviews related to SPOS have been contributed by experts in these fields of research: In the paper by Prof. Ilia and co-worker entitled “Solid-Phase Synthesis of Phosphorus Derivatives”, different approached for the solid phase synthesis of oligonucleotides, nucleobases, nucleoside, phosphates and phosphonates are extensively reviewed. Prof. Ohtaka in the paper “Transition-Metal Nanoparticles Catalyzed Carbon-Carbon Coupling Reactions in Water” reports the most important advances in Carbon-Carbon bond formation reactions such as Suzuki coupling, Heck reaction, Sonogashira coupling, Stille coupling, Hiyama coupling and Ullmann coupling catalyzed by different transition metal nanoparticles. The final contribution to this special issue is provided by Rokhum et al. This review entitled “Recent Application of Polystyrene-Supported Triphenylphosphine in Solid Phase Organic Synthesis” covers several applications of polymer-bound triphenylphosphine as a catalyst as well as a regent in different chemical transformations such as Henry reaction, Wittig reaction, Mitsunobu reaction, esterification reaction, and cross-coupling reaction. As Guest Editors we would like to take this opportunity to thank all the authors who have kindly agreed to our invitation and contributed a review for this special issue. We also wish to thank all the reviewers for their support in evaluating the submitted manuscripts. We sincerely thank the Editor-in-Chief, Prof. György Keglevich and the Editorial Manager Ms. Sanober Maqbool for their constant support in the successful publication of this special issue. It has been a great pleasure to work with Bentham Science Publishers.

In the last decades important challenges have been overcome due to the comprehension of the supramolecular organic chemistry. Non-covalent interactions and aggregation properties often play a central role in the development of new bioactive compounds, carriers systems and delivery devices as well as in the improvement of natural products as starting materials for innovative uses, including tissue engineering and medicine. In many cases different techniques are required to characterize newly formed supramolecular systems in term of dimension, morphology, microviscosity and stability, or to point out the aggregation tendency of the investigated molecules. Promising strategies are also based on the formation of aggregates or the inclusion of molecules into carrier systems for new targets; the characterization of nanoparticles; the use of the therapeutic polymers; the synthesis of molecules mimicking natural compounds; the applications of traditional or modern techniques to highlight aggregation properties. The aim of this special issue is to report the recent advances in topic aspects of the supramolecular organic chemistry in a large variety of applications involving self-assembly process and including all cases in which the supramolecular behavior represents the relevant key for future perspectives in the scientific research.

Metal-organic frameworks (MOFs), also known as porous coordination polymers (PCPs), are constructed from the coordination of metal ions or metal clusters with organic ligands. MOF studies have emerged as one of the most important topics in chemistry and materials science in the past two decades. The porosities of MOF materials can be systematically tuned by judicious selection of molecular building blocks, and a variety of functional sites/groups can be introduced into metal ions/clusters, organic linkers, or pore spaces through pre-designing or post-synthetic approaches. These unique advantages enable MOFs to be used as a highly versatile and tunable platform for various applications in gas storage and separation, chemical sensing, catalysis, and biomedicine. MOFs have some intrinsic advantages to develop as a new class of catalytic materials, such as their ultra-high surface areas (up to 7000 m2 /g), tunable pore sizes/shapes, and easily immobilized catalytic active centers into metal nodes or organic linkers. Also, some catalytically active molecules or nanoparticles could be encapsulated into the cavities of MOFs. These attractive features have led to a rapidly growing number of MOFs for heterogeneous catalysis. The purpose of this thematic issue is to summarize and highlight the advanced development of MOFs and their emerging applications in organic chemistry related fields. The topic of this issue will cover several fields that be contributed from experts from organic chemists, inorganic chemists and materials scientists: (1) The advanced development of MOFs, such as novel synthetic approach, post-synthesis, and In situ growth mechanism studies of MOFs; (2) Emerging and promising applications of MOFs, such as light hydrocarbon separation, catalytic organic transformation, photocatalysis, sensing of small molecules, bioimaging and drug delivery.

Inflammation results from a process in response to noxious stimuli in from tissues by pathogenic agent and / or irritated or damaged cells from an inflammatory immune response involving the immune cells, blood vessels and molecular inflammatory mediators [1]. Inflammatory diseases may be provided by an acute or chronic phase. In the acute phase we have an innate immune response by characterized flush appearance, heat and increasing the entry into service on site [2]. In contrast, the chronic phase is from persistent acute inflammation by the recruitment of monocytes, leukocytes and macrophages as well as proinflammatory cytokines. At this stage one can achieve with tissue destruction and fibrosis necrosis site [3]. Chronic inflammation may lead to a number of diseases such as asthma [4], rheumatoid arthritis [5], atherosclerosis [6], intestinal diseases [7], among others. The objective for this thematic issue is to report recent studies about different approaches in drug discovery, which comprises synthesis, semi-synthesis, searches for new targets, natural products, evaluation of biological activities, and/or theoretical approaches as structure-based approaches, SAR, QSAR, docking and several cheminformatics methods [8], for investigation and selection of new lead molecules. These efforts involve several studies to aid the drug discovery of new options of treatment of inflammatory diseases.

I propose you a revision of the state of the art in the field nanotechnology-organic chemistry. This a very actual, wide and open area of research that is the joint of many different research fields. Due to this fact, there is not a book or a thematic issue that gives its state of the art. Base on this I believe that this area needs thematic issue like this. I propose to include the study of the organic molecules that are used in the last years for the modification of surfaces (metallic or not: mainly silicon, organic substrates as cellulose, and carbon) and the main carriers that are used in the delivery of actives compounds, from lipid nanoparticles to nanofibres. Moreover I propose to include a chapter focused on the delivery of antitumoral actives.

Biopolymer means the polymers which are produced in a natural way by living species. In general their molecular structures are composed of the units of saccharides, nucleic acids and also different additional chemical side chains contributing to their consequences. The utilization of the biopolymers by Humans comes under the category of food, clothing and furniture. On the other side if we talk about the industrial applications of biopolymers, then it is found that fossil fuels are the substantial origin for the manufacture of the commercial products for example, plastics which is presently used at very high scale. Some of the biopolymers examples are such as Proteins, Carbohydrates, Lipids, DNA, RNA, Nucleic acids, Peptides, Polysaccharides (glycogen, starch, cellulose etc.). There are basically four main classifications of biopolymers available considering both natural and synthetic polymers carbohydrate based biopolymer, starch based biopolymer, biopolymers based on synthetic materials and cellulose based biopolymers. In this issue we are mainly focusing on the history and origination of the biopolymers, their classifications and biopolymer based formulations such as Biocomposites etc.. We will also discuss about the various applications of these biopolymer formulations in the field of biomedical engineering and industrial fields. Sugar based polymers, such as polylactides, naturally degenerate in the human body without producing any harmful side effects. Polylactides are generally used as surgical implants. Starch based biopolymers can be used for creating conventional plastic by extruding and injection molding. Biopolymers based on synthetic are used to manufacture substrate mats. Cellulose based biopolymers, such as cellophane, are used as a packaging material.

In the Thematic Issue “Transformation of POPs in the environment" the selected organic micropollutants listed by Stockholm convention as well as micropollutants listed in some other international and national law legislations will be described. There will also be characterized some other organic micropollutants that are not listed in current legislations but they cause hazard for health and people life due to their estrogenic biological activity, carcinogenic, mutagenic or teratogenic activity. The organic micropollutants include: polychlorinated dibenzodioxyns PCDD, polychlorinated dibenzofurans PCDF, polychlorinated biphenyls PCBs, selected insecticides and pesticides, polycyclic aromatic hydrocarbons (PAHs), halogenated compounds (determination as AOX) and by-products of water treatment, di-2- ethylocsylophtalans DEHP, nonylphenols NPE and ethoxylated of nonylphenols compounds NPEO and some surfactants, such as linear alkylo benzosulphonans LAS. Moreover, the current topic is the presence in the environment emerging organic contaminants as well as biologically active substances so called as endocrine disrupting compounds such as: pharmaceutics and cosmetics remains and bactericidal compounds (personal care products PCP), flame retardants Frs and preservatives and impregnates.

In the Thematic Issue “Transformation of POPs in the environment" the selected organic micropollutants listed by Stockholm convention as well as micropollutants listed in some other international and national law legislations will be described. There will also be characterized some other organic micropollutants that are not listed in current legislations but they cause hazard for health and people life due to their estrogenic biological activity, carcinogenic, mutagenic or teratogenic activity. The organic micropollutants include: polychlorinated dibenzodioxyns PCDD, polychlorinated dibenzofurans PCDF, polychlorinated biphenyls PCBs, selected insecticides and pesticides, polycyclic aromatic hydrocarbons (PAHs), halogenated compounds (determination as AOX) and by-products of water treatment, di-2- ethylocsylophtalans DEHP, nonylphenols NPE and ethoxylated of nonylphenols compounds NPEO and some surfactants, such as linear alkylo benzosulphonans LAS. Moreover, the current topic is the presence in the environment emerging organic contaminants as well as biologically active substances so called as endocrine disrupting compounds such as: pharmaceutics and cosmetics remains and bactericidal compounds (personal care products PCP), flame retardants Frs and preservatives and impregnates.

Due to their essential roles in photosynthesis, chlorophylls are omnipresent from photosynthetic prokaryotes to higher plants, being considered the most important pigments on Earth. Such vital function derives from its structure, chlorophylls can absorb light quanta effectively, but also they can release and take up electrons reversibly. Chlorophylls are cyclic tetrapyrroles carrying a characteristic isocyclic five-membered ring that are functional in light-harvesting or in charge separation in photosynthesis. The general term ‘chlorophylls’ includes several kinds of chlorophyll structures depending of the unsaturation degrees of the macrocycle. Fully unsaturated porphyrin macrocycle is present in c-type chlorophylls of chromophyte algae and some prokaryotes. The chlorin system shows a saturated bond between C17-18 and it is present for example in the chlorophylls a and b of oxygenic organism and in some bacteria. Finally, the bacteriochlorin type exhibits two saturated bonds at C7-8 and C17-18, and it has been described in bacteriochlorophylls of anoxygenic bacteria. During the last year, mass spectrometry has been used successfully to obtain information of the structural configuration of the different chlorophylls, not only related with identification and characterization but also providing insights of the mechanism of reaction. The present theme issue will review the recent developments in the field of mass spectrometry covering different chlorophyll structures.

It has become the scientific focus to advance the synthesis methods and the analysis techniques for organic materials because of these materials’ importance in food, pharmaceutical and medical industries. A good understanding of the properties of a material (e.g., composition, chirality, structure, thermal stability and phase transformation) is crucial for food processing and safety, drug design and manufacturing and medical applications. Thus there’s an increasing demand for a wide range of modern characterisation techniques. This proposed thematic issue will try to present the latest advances, trends and challenges in modern synthesis methods and analysis techniques by collecting the review articles on some emerging techniques (e.g., 3D printing, small angle X-ray scattering) as well as some more traditional techniques (e.g., nuclear magnetic resonance, differential scanning calorimetry and Xray diffraction). It will also highlight some in-situ monitoring techniques (e.g., the simultaneous X-ray diffraction- differential scanning calorimetry technique for the characterization of solid pharmaceuticals).

Chitosan, a natural polymer obtained by alkaline deacetylation of chitin, is the only cationic polysaccharide in nature. Chitosan could be chemical modified by different ways, such as oligomerization, alkylation, acylation, quternization, hydroxyalkylation, carboxyalkylation, thiolation, sulfation, phosphorylation, enzymatic modifications and graft copolymerization along with many assorted modifications. Then many derivates of chitosan could be obtained. Chitosan and its derivates show excellent biological qualities: they are biocompatible, biodegradable, mucoadhesive and non-toxic, and exhibit antimicrobial, antiviral gene transfection and immunoadjuvant properties. Chitosan and its derivates have a variety of promising applications in medicine and pharmaceutics and are presently considered as a novel carrier material in drug delivery systems, gene therapy, tissue engineering scaffold, wound healing, antibacterial, fat binder, hemostatic agent, hypocholesterolemic effect as indicated by the large number of studies published over the last few years. They can be easily processed in diverse forms, such as membranes, microparticles/nanoparticles, fibres, hydrogels or sponges, and allowing the design of a variety of medical and pharmacological devices adaptable to end purposes. In this special issue, I’ll bring together a number of top-ranked international scientists to discuss the recent advances about the strategies for design, synthesis, functionalization and applications of chitosan and its derivates for applications in medical materials. This special issue is aiming for a broad audience of readers in the field of material sciences, chemistry, medicine and pharmaceutics.

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