Unit of Medicinal Chemistry LIFE-EDESIA workshop Milan, Dicember 10 th 2014 THE ROLE OF CHEMICAL SYNTHESIS IN SUPPORT OF THE SUBSTITUTION PRINCIPLE Ferdinando Fiorino Elisa Perissutti Università degli Studi di Napoli Federico II (UniNA) Department of Pharmacy
Workplan The LIFE EDESIA project aims to contribute to improve implementation of the REACH Regulation by providing at least one suitable alternative for bisphenol A/BPA, phthalates and parabens. These objectives will be achieved by the following actions:;.synthesizing the selected substitutive chemicals; Creating prototypes that use the substitutive chemicals, and to assess them for release of chemicals; and Demonstrating the feasibility of the substitution of the EDCs considered in the project in industrial applications.
Activities in EDESIA ACTION B.3: Synthesis of the chemicals The synthesis will be performed applying the most modern techniques of organic synthesis, developed with particular attention to the environmental impact. Advanced synthetic technologies, such as microwave reactors specifically designed for organic synthesis and all those technologies that allow to perform reactions both in the presence of solvents, such as ionic liquids, alternative to common volatile organic solvents, and in "solvent free" conditions will be used (" Green chemistry "). The synthesized molecules will be accurately characterized in order to acquire useful information to streamline their technological characteristics of usability and interaction with living matter. In particular: Definition of lipophilicity to different ph values of physiological relevance; Determination of affinity values for membrane phospholipids and for the serum-proteins; Profiles of solubility in water at various ph; Characterization of possible decomposition products; Development of analytical methods useful for the determination of trace products in biological matrices.
Activities in EDESIA Task B.5: Prototyping and testing for industrial purposes in 3 application domains Preservatives are widely used, beside in food industry, in both cosmetic and pharmaceutical fields. The use is mainly requested for products containing water to control microbiological growth. It is important to underline that even products based on lipophilic matrices often need the addiction of preservatives since they can include more or less relevant percentages of water. This means that preservatives must be added in a large majority of cosmetic and pharmaceutical preparations, e.g. both liquid and semisolid (lotions and creams, respectively) water in oil or oil in water emulsions, hydrophilic ointments, and even water-absorbing lipophilic ointments. More relevant for public health is the addiction of preservatives in orally dosage forms such as syrups, often intended for children medication. To date, parabens, the most widely used preservatives, can be substituted (in some cases) by other preservatives but the better application profiles may be achieved by the new paraben-like compounds synthesized in the present project. This action will start at month 28 and finish at month 33.
What do we mean by Substitution Substitution is the replacement of a substance, process, product or service by another that maintains the same functionality. Substance by Substance Process by Process Product by Service Substitution will only be successful where the socioeconomic requirements of all the stakeholders can be satisfied. Substitution should aim, over the whole life cycle of the replacement, to obviate any negative impacts on human health or the environment and improve resource efficiency.
Is it an acceptable substitute? 1. Functionality: Can an acceptable functionality be delivered? 2. Compatibility: Is the substitute compatible with all other aspects? 3. Availability: Is sufficient available and is the supply secure? 4. Depth of knowledge: Is the level of knowledge of the substitute at least as good as that of the original? 5. Human & Environmental Impact: What are the impacts on human health & the environment of the original and the alternative? 6. Efficiency of resource utilisation: Does the substitution lead to any changes in resource utilisation including quality and quantity of waste production? 7. Socio-Economic Consequences: What are the socio-economic consequences of the change to the end consumer and to all the other actors in the supply chain?
Substitution decisions frequently involve difficult trade offs Substitution decision based on hard data Substance Y is safe in use but substance X has a substantially lower acute toxicity to humans. However if we substitute substance X for Y in our manufacturing process it increases the carbon footprint by 10% and produces 5% more solid waste. Substitution decision based on soft data Product A is highly effective and the brand leader in a highly competitive market. Product B is a little more expensive, is slightly less effective but has a significantly lower environmental footprint.
Examples of Successful Substitution Process for process Use of supercritical CO 2 to replace organic solvents Substance for substance Replacement of arsenic in wood preservatives Mechanism for mechanism Low friction antifouling surfaces to replace copper based paints Product for product Introduction of cold water laundry detergents Service for product Closed loop chlorinated solvent recycling
What is Green Chemistry? The design of chemical processes, products and technologies that reduces or eliminates the use and generation of hazardous substances
1- Prevention 7 - Use of Renewable Feedstocks 2 - Atom Economy 8 - Reduce Derivatives 3 - Less Hazardous Chemical Syntheses 9 - Catalysis 4 - Designing Safer Chemicals 10 - Design for Degradation 5 - Safer Solvents and Auxiliaries 11 - Real-time Analysis for Pollution Prevention 6 - Design for Energy Efficiency 12 - Inherently Safer Chemistry For Accident Prevention
Green Chemistry The focus area of the EPA s Green Chemistry Program considers : - The use of alternative synthetic pathways - The use of alternative reaction conditions - The design of safer chemicals that are, for example, less toxic than current alternatives or inherently safer with regard to accident potential.
An Ideal Chemical Reaction: Is Simple. Is Safe. Has a High Yield and Selectivity. Is Energy Efficient. Uses Renewable and Recyclable Reagents and Raw Materials.
LIFE-EDESIA kick-off meeting Rome, October 14 th 2013 Green Chemistry Methodologies - Alternative Feedstocks. - Green Solvents. - Synthesis Pathways. - Inherently Safer Chemistry.
Pollutant Chemical Industries: Acid Catalysis and Partial Oxidation Acid catalysed reactions liquid phase organic reactions. Problems Reactions are catalysed by strong Brønstread (H 2 SO 4, HF) and soluble Lewis (AlCl 3, BF 3 ) that are difficult to separate from the organic product and lead to large volumes of hazardous waste. Alternative: using heterogeneous catalysis. Partial Oxidation of organic molecules. Problems manufacturing methods include toxic and corrosive chemicals. Ex. processes based on cobaltacetic acid- bromide, or using Cr(VI) and Mn(VII). They produce large volumes of an organic acid and toxic metal waste. Alternative: less toxic catalytic agents.
Criteria to Select Solvents Concerning Pollutant Chemical Industries A. Energy Production B. Petrochemical Manufacturing and Processing C. Pulp & Paper Mills D. Chemical Compounds Production E. Pesticides Less Hazardous : Scrutinize different options to minimize all hazards. Human Health : The potential impact it might have, because of it s large quantity. Also important to consider the environmental impact. Environment (Global and Local) : Determine the potential effects. Alternative Solvents : Include supercritical fluids, aqueous applications, polymerized/immobilized solvents, ionic liquids, solvent-less systems and reduced hazard organic solvents
Alternative Reaction Pathway Selection Addition ( A + B AB) No waste needs to be treated because the reaction is direct. Substitution (AB + C AC + B) Necessarily generates stoichiometric quantities of substances as by products and waste that are not part of the target molecule. Elimination (AB A + B) Does not require other substances, but does generate stoichiometric quantities of waste that are not part of the final target molecule.
Functional Group Approach to Green Chemistry Structure Activity Relationship Used to determine a potential structural modification that may improve the substance s safety. Elimination of Toxic Functional Groups Substances in the same functional group tend to have the same toxicity. If it is possible, eliminate any substances from a given group, or mask the toxic substance s property rendering it safe. Reduction of Bioavailability Modifying or eliminating certain properties that cause toxic substances to be bioavailable. Design for Innocuous Fate Designing substances to ensure they degrade after their useful life.
Tools Medicinal Chemistry can be a useful tool to get an answer to the first end-point
CHEMICAL STRUCTURES OF SOME PHTALATE AND PARABEN DERIVATIVES n-butyl benzyl phthalate (BBP) Dibutyl phthalate (DBP) Propylparaben bis(2-ethylhexyl) phthalate Diisopropyl phthalate (DIP) Butylparaben
Microwave heating Advantages The identification of a lead compound starting from a larger compound librar is easier. Why is it so popular among Medicinal Chemists? Fast heating allows higher number of componds Use of combinatorial O S chemistry H 3 approches CH 2 COOC combined enhances library generation N H Higher yields obtained Greener procedures allowed NO 2 Just One winning compound (Drug Candidate) Compound SM-15811: Libraries IC 30 17 nm
Green Chemistry is the utilization of a set of principles that reduce or eliminate the use or generation of hazardous substances in chemistry. Its basic principle is to conduct chemical reactions simultaneously, protecting the environment, through the use of chemical processes deemed suitable to avoid pollution. In this contest, water as solvent is a good option because of its abundant, nontoxic, non-corrosive, and non-flammable nature. Although microwave assisted reactions in conventional solvents have developed rapidly, the center of attention has recently shifted to environmentally benign processes. The association with microwaves allows to overcame problems related to water traditional chemistry such as insolubility of most of organic reactants or difficulty in the product isolation from aqueous reaction mixture. In later years various examples of reaction accelerations, selectivity, and higher yields have been reported using water as solvent or in some cases without the use of any solvent (solvent free