Preface Free

The consolidation of skills in organic chemistry requires learning quite extensive concepts concerning functional groups, molecular structure, properties and reactivity for which laboratory practices are essential. Additionally, laboratory practices frequently lead to many hurdles such as those related with handling of moisture sensitive compounds or purification of mixtures, for which a proper understanding of the reaction intervenients is needed. The manipulation of organic compounds can be a very challenging task, and very skilled organic chemists are often pivotal to performing a needed synthetic modification. Fortunately, this has not prevented researchers from different fields of science from embracing organic chemistry and using their skills in the preparation of new organic compounds, new materials or even in the modification of complex biomolecules such as proteins. In this context, strengthening students from different degrees with synthetic skills can lead to a strong and rewarding asset for their professional prospective. To consolidate skills and knowledge gathered from books, tutors from different courses implement experiments that they consider appropriate toward achieving the desirable learning essentials according to the targeted teaching goals, laboratory availability and costs. This consolidation is typically achieved by selecting, adapting and/or improving experiments selected from books, specific educational journals and other resources, namely scientific journals. Comprehensive Organic Chemistry Experiments for the Laboratory Classroom (COCELC) contains 233 experiments covering a range of synthetic transformations from introductory to advanced level. It aims to remedy the lack of experimental diversity of existing sources of organic chemistry experiments for teaching. These experiments were tested in teaching laboratory environments and result from the contribution of authors from universities, colleges and other higher education institutions worldwide.

The optimisation of many laboratory experiments in terms of costs and time have allowed the introduction of organic chemistry laboratory courses in many degrees beyond chemistry majors. The transversal character of organic chemistry, spanning the synthesis of natural products to materials science, is vividly represented by the collection of experiments gathered in this book, focusing on many varied topics such as medicinal chemistry, natural products, green chemistry, polymerisations or asymmetric synthesis.

For each experiment the following details are provided: duration, hazard level, difficulty level, target students, functional groups involved, concepts involved, required chemicals, equipment and experimental techniques, background, complete experimental procedure, safety information, interpretation of results, questions for discussion with students and specific comments and advice from the authors on getting the best outcome from the experiment.

Gathering experiments from very different countries and institutions with varied curricula in their courses demanded the creation of a set of rules to ease the normalization of the experiments into different categories regarding hazard, difficulty and study levels, as follows:

• Low: no special measures are needed for the manipulation of the chemicals or the equipment involved in the experiment. Nevertheless, basic safety measures, like the use of a lab coat and safety goggles, should be considered at all times.

• Moderate: some of the chemicals used in these experiments are known to be toxic or flammable. The use of fume hoods is advisable. This level can also mean that these experiments may require the handling of some equipment that requires particular attention. For instance, the use of a rotatory evaporator or any vacuum system.

• High: such experiments deal with the manipulation of highly toxic chemicals or solvents. They should be executed by students with proper training and who are aware of the risks involved in the handling of such chemicals.

• Low: the experiment can be easily performed by all kinds of students, since it does not involve the manipulation of hazardous chemicals or any techniques besides elementary ones such as extractions, distillations or crystallizations. The product characterization for these experiments is usually performed by the melting point, infra-red spectrum or some physical aspect of the final product.

• Medium: some considerations regarding the procedure should be taken into account to successfully perform the experiment. Some specialist knowledge such as the influence of stirrer speed on the reaction outcome, or the crystallization rate of the final product are examples. This information is given by the author of the experiment to the instructor in the ESI. This level may also relate to the use of equipment for which the student should be previously trained, for instance HPLC or interpretation of NMR spectra.

• High: this type of experiment deals with more advanced laboratory techniques. The manipulation of moisture-sensitive chemicals and the need for anhydrous conditions to perform the reactions are examples of what can be found in these experiments. Preparation of compounds in which purification by column chromatography is needed also falls into this category.

Level of study: although it is assumed that students in organic chemistry usually start their studies by having a general overview of the preparation and reactivity of common functional groups, intermediate level experiments can be performed by elementary students, if emphasis on synthetic organic chemistry was given in teaching.

• Introductory: recommended for teaching classes of basic organic chemistry, for students that are dealing with organic chemistry for the first time in the laboratory (e.g. for early bachelor students). Usually, this represents the manipulation of general functional groups.

• Intermediate: recommended for students that have taken previous courses in organic chemistry and feel comfortable with unitary operations, but that are still learning about transformation of functional groups (e.g. for final-year bachelor students). Usually, this represents the transformation of more than one functional group, and the preparation of specific molecules. NMR spectral analysis of the products is usually involved.

• Advanced: recommended for students that have taken advanced courses in organic chemistry (e.g. for masters and PhD students). Experiments regarding the preparation of more demanding molecules and the use of recently developed transformations are focused on.

This book would not have been possible without the commitment and work of the authors of each experiment. They are deeply acknowledged for their contributions. More importantly, students from the different teaching institutions that were anonymously involved in the validation, reproduction, optimisation or creation of these experiments are equally acknowledged.

Carlos A. M. Afonso, Nuno R. Candeias, Dulce Pereira Simão, Alexandre F. Trindade, Jaime A. S. Coelho, Bin Tan and Robert Franzén