Green Chemistry: Opportunity in Drug Discovery Research (Part 1)

Abstract

The synthetic approaches towards the development of different varieties of organic molecules of potential medicinal interest have taken a paradigm shift in the last few decades. In contrast to the conventional approaches in the organic synthesis, where achieving the best reaction yield of a target, the molecule was the prime focus without paying much attention towards the impact of the synthetic methodology adopted for it, on the Safety, Health, and Environment (SHE), the development of environmentally benign and green synthetic reaction protocols and technology is the principal goal in the present scenario [1-3]. In that direction, the development of the concept of Green Chemistry and its twelve basic principles by Prof. Paul T. Anatsas and Prof. John C. Warner work well as a promising guiding tool for the synthetic and medicinal chemist [4]. The prevention or minimization of waste generation, increasing % atom economy, decreasing environmental factors (E Factor), catalysis, efficient use of energy, etc., are some of the notable key points of the basic green chemistry principles [4]. The applications of cost-effective, safe, easy, straight-forward, high-yielding, selective (regio-, chemo-, and sterero-), sustainable, and environmentally benign approaches for generating drug candidates or potent scaffolds that fulfill the “green chemistry” principles are incredibly imperative [5]. Toward this end, this thematic issue presents a judicious endeavor to communicate the impact of Green Chemistry in particular to their opportunity in drug discovery & development to the readers. In this thematic issue titled “Green Chemistry: Opportunity in Drug Discovery Research,” the development of common practical synthetic methodologies which are in accordance with the principles of green chemistry towards achieving the various types of organic transformations is widely covered. In particular, the application of green and eco-friendly reaction protocols for the synthesis of pharmacologically important organic scaffolds has been highlighted. This issue covers sixteen different topics (divided into two separate parts with eight manuscripts in each section) that would widely illustrate the scope of green chemistry in various aspects of sustainable synthetic strategies including, reactions in ionic media [6], aqueous condition [7], solvent-free condition [8], non-conventional energy source like microwave condition [9], ultrasonic condition [10], visible-light-induced condition [11], one-pot multi-component condition [12], biocatalysis [13], organocatalysis [14], heterogeneous catalysis [15], click condition [16, 17], etc. towards the development of pharmacologically active new chemical entities (NCE s) widely explored in drug discovery research. Total sixteen leading groups who are very active in their field have kindly accepted our invitation to participate in this thematic issue by providing an overview on the recent advances on selected emerging topics on green chemistry and contributed to this COC venture; for that, we are grateful to them for their excellent contributions. In Green Chemistry-Part 1 issue, eight eminent research groups in the field of sustainable chemistry have briefly presented their overview listed as follows: Prof. Pellissier in Organocatalytic Asymmetric Tandem/Domino Reactions Towards Access to Bioactive Products introduced a nice and interesting overview on major developments on powerful enantioselective organocatalytic asymmetric catalysis including Michael-initiated-, aldol-initiated and other domino reactions as the key steps to produce high yields of important intermediates as well as biologically relevant simple-to-complex molecular architectures [18]. Prof. Keglevich et al., in Synthesis of Phosphonates, Phosphinates and Tertiary Phosphine Oxides by Pdor Ni-Catalyzed MicrowaveAssisted P–C Coupling Reactions without the Addition of Conventional Ligands presented a typical and useful overview on microwave (MW)-induced effective tool applied for the P–C coupling reactions of vinyl/aryl halides with dialkyl phosphites in the presence of an appropriate Pdor Nicatalyst [19]. In addition to the mechanistic details to establish the optimum reaction conditions, the authors also provide the factors affecting the activity of the catalyst to form complex as well the reactivity of the reactants in the P–C coupling reactions. Also, this powerful protocol displayed a nice expansion of the reagents and catalysts predominantly for the simplification of the catalytic system to be considered as the environmentally benign tool [19]. Prof. Matsumura and his group in Oxidized Polysaccharides as Green and Sustainable Biomaterials considered the notable non-toxic, biocompatible, sustainable, and bioavailability nature of carbohydrates and described the general consideration of oxidized polysaccharidebased candidates useful for their various emerging applications in the area of biomaterials and biomedical sciences [20]. Prof. Girija Singh in Greener Approaches to Selected Asymmetric Addition Reactions relevant to Drug Development presents an interesting aspect of environmentally benign parameters (i.e., a reaction in greener solvents like aqueous media or reaction under solvent-free conditions or reaction at room temperature or reaction under non-conventional energy source, etc.) in a number of asymmetric addition reactions (e.g., aldol reaction, Michael addition, aza-benzoin reaction, and Mannich reaction) to produce a wide range of biologically relevant molecular scaffolds [21]. Prof. Diganta Sarma and his group in Synthesis of Medicinally Relevant Scaffolds-Triazoles and Pyrazoles in Green Solvent Ionic Liquids nicely explored the emerging scope of modular Click Chemistry to produce biologically potent regioselective triazole analogues under green conditions via reaction in ionic liquids [22]. The authors also present a few selected and practical syntheses of pharmacologically active pyrazole heterocycles using ionic liquid as suitable reaction media. Prof. Brahmachari et al., in Ultrasound-Promoted Organic Synthesis A Recent Update considered the inherent properties of ultrasonication to minimize wastes as well as to reduce energy or reaction time and nicely presented an interesting overview on ultrasoundpromoted organic transformations involving both C-C, C-N, C-O, and C-S bond-forming reactions [23]. Prof. Ghanshyam Bez and his group in Application of nature’s chiral pool in environmentally sustainable organic synthesis brilliantly presented emerging applications of nature’s chiral pool as suitable catalysts, solvents, or raw materials (e.g., carbohydrates, amino acids, and their readily accessible derivatives) for easy access of a diverse range of biologically active molecular scaffolds [24]. Please provide corresponding author(s) photograph size should be 4 x 4 inches