Undergraduate Organic Chemistry Laboratory Research Articles

Microwave-Enhanced Organic Syntheses for the Undergraduate Laboratory: Diels−Alder Cycloaddition, Wittig Reaction, and Williamson Ether Synthesis

Microwave heating enhanced the rate of three reactions typically performed in our undergraduate organic chemistry laboratory: a Diels−Alder cycloaddition, a Wittig salt formation, and a Williamson ether synthesis. Ninety-minute refluxes were shortened to 10 min using a laboratory-grade microwave oven. In addition, yields improved for the Wittig salt and ether preparations. The Diels-Alder cycloaddition of N-phenylmaleimide and 1,3-cyclohexadiene in absolute ethanol in a closed vessel and 130 °C gave 84−90% yields. Formation of the Wittig salt, benzyltriphenylphosphonium chloride, from triphenylphosphine and benzyl chloride gave yields greater than 90% when heated in acetonitrile at 200 °C Yields doubled in the Williamson ether synthesis of 2-ethoxynaphthalene, from 2-naphthol, methanolic potassium hydroxide, and iodoethane with microwave heating at 130 °C.

Palladium-Catalyzed Synthesis of a Benzofuran: A Case Study in the Development of a Green Chemistry Laboratory Experiment

A well-recognized principle of green chemistry is the use of catalysis to effect chemical transformations. It is difficult, perhaps even impossible to find a current issue of a chemical journal that does not present the use of catalysis, with reports of metathesis-type reactions and of palladium-catalyzed transformations particularly prevalent. Despite the ubiquity of palladium-catalyzed reactions in the practice of synthetic chemistry, however, it is uncommon to find examples of palladium catalysis in the undergraduate laboratory curriculum. In this article, we present our development of such an experiment, beginning from its conception and discussing the progression of modifications and improvements required to convert a reaction as reported in the primary chemical literature to a procedure suitable for the undergraduate organic chemistry laboratory. This presentation, while focused on the development of a laboratory teaching module, serves to illustrate more generally the concepts, principles, and decision-making involved in the practice of green chemistry.

Integrating Computational Molecular Modeling into the Undergraduate Organic Chemistry Curriculum

An instructional unit is described for integrating computational molecular modeling into the undergraduate organic chemistry laboratory curriculum. The approach emphasizes use of computational modeling as a readily available, efficient tool for understanding structure and reactivity, predicting products, and rationalizing the results of organic reactions performed in the laboratory. This approach has been used in a large organic chemistry lab program for five semesters with favorable results. Through individual hands-on experience with computational modeling, students gain a more complete and correct understanding of structure, bonding, and reactivity.

Synthesis of Imidazolium Room-Temperature Ionic Liquids. Exploring Green Chemistry and Click Chemistry Paradigms in Undergraduate Organic Chemistry Laboratory

Room-temperature ionic liquids have become a widely used alternative to conventional molecular organic solvents as a reaction medium. Few preparations of ionic liquids provide efficient access to these solvents; furthermore, none is fully adaptable to an undergraduate organic chemistry laboratory. In this article, several imidazolium-based ionic liquids are formed in facile and efficient one-pot procedures using water or ethanol as a solvent. These reactions are suited for a four-hour organic chemistry laboratory without special equipment.

Greener Solutions for the Organic Chemistry Teaching Lab: Exploring the Advantages of Alternative Reaction Media

A major approach for implementing green chemistry is the discovery and development of synthetic strategies that reduce the quantity of solvent needed, eliminate it altogether, or rely on new reaction media. An increasing number of examples have demonstrated that greener reaction solvents or media can enhance performance as well as reduce hazard. Here we describe four experiments designed for the undergraduate organic chemistry laboratory that illustrate both enhanced performance and a greener approach: (i) a solventless aldol condensation that involves the reaction of two solid reagents, (ii) a solvent-free, room temperature Diels–Alder reaction followed by an intramolecular nucleophilic acyl substitution, (iii) a Diels–Alder reaction in water, and (iv) a Diels–Alder reaction in polyethylene glycol (PEG) that may be conducted using microwave heating. The alternative solvents or reaction media used in these experiments not only reduce the use of hazardous and volatile organic solvents but also enhance the transformations by increasing the rate of reaction or facilitating recovery of the product. These thoroughly tested laboratory experiments are convenient, inexpensive, and rapid, thereby providing an opportunity to introduce green chemistry into educational settings easily.

Óleo essencial de limão no ensino da cromatografia em camada delgada

This paper describes a simple experiment employing the essential oil of limes which can be applied in undergraduate organic chemistry laboratory classes for the teaching of thin layer chromatography (TLC). The experiment consists in submit lime peel oil to TLC separation employing hexane and dichloromethane as the eluents and five different systems for visualization of the chromatogram. In one experiment it is possible to teach the different variables of the TLC technique. This experiment may also be performed following vapor distillation and liquid-liquid extraction technique in experimental classes.

Borohydride Reduction of Estrone. Demonstration of Diastereoselectivity in the Undergraduate Organic Chemistry Laboratory

This experiment presents a guided-inquiry approach to the demonstration of diastereoselectivity in an undergraduate organic chemistry laboratory. Chiral hindered ketones such as estrone, undergo facile reduction with sodium borohydride in a highly diastereoselective manner. The diastereomeric estradiols produced in the reaction can be analyzed and differentiated by thin-layer chromatography and melting point.

Synthesis of the Commercial Antidepressant Moclobemide

An experiment for the undergraduate organic chemistry laboratory is described in which students synthesize the commercial antidepressant drug moclobemide, marketed under the trade name Manerix. This one-step synthesis starts from commercially available material and produces moclobemide in high yield. The product is initially isolated as its hydrochloride salt via precipitation. After recrystallization and treatment with base moclobemide is isolated in pure form. The purity and identity of the product are confirmed by melting point and NMR and IR spectroscopy.

Extração de β-caroteno de cenouras: uma proposta para disciplinas experimentais de química

This paper reports on the development of a simple and fast procedure for β-carotene extraction from carrots and its quantification by UV/Vis spectroscopy. Carotenoids extracted from carrots may also be used as alternative reagents for TLC (thin layer chromatography) detection of natural compounds with antioxidant properties, replacing the commercial p.a. grade β-carotene. Although this reagent had around 10% b-carotene, it proved to be as efficient for TLC analysis as the commercial p.a. grade β-carotene. This practice is a useful alternative for teaching undergraduate organic chemistry laboratory classes.

Synthesis and Analysis of a Versatile Imine for the Undergraduate Organic Chemistry Laboratory

An important synthesis omitted from organic laboratory texts is that of imine preparation, a particularly relevant intermediate both synthetically and biologically. In this experiment students prepare and analyze N-p-methoxyphenyl (N-PMP) α-imino ethyl glyoxalate, an imine that has been used in the synthesis of biologically active molecules. In the first step, an ethyl acetate solution of p-anisidine and ethyl glyoxalate is reacted in the presence of molecular sieves at room temperature for 15 minutes or one week. The adapted literature technique used methylene chloride as the solvent, but ethyl acetate was an equally effective greener alternative. Students then vacuum distill the Celite-filtered reaction mixture to remove solvent. The imine product can then be analyzed by standard organic instrumental techniques, such as 1H NMR and GC–MS. The workup and analysis take 2–3 hours to complete, depending on instrument availability. Thus, the entire experiment can either be completed in one or two laboratory...

Synthesis of Unsymmetrical Alkynes via the Alkylation of Sodium Acetylides. An Introduction to Synthetic Design for Organic Chemistry Students

This article describes an inquiry-based experiment for the undergraduate organic chemistry laboratory. The use of acetylides as nucleophiles is a common theme used in most organic textbooks as an introduction to retrosynthetic analysis. We have developed a problem-based application of this methodology for the first-semester organic laboratory. In this experiment, students are assigned to work in teams to design a microscale synthesis of an unsymmetrical alkyne using commercially available terminal alkynes and alkyl halides. Team members work collaboratively to perform the synthesis and characterize the resulting products using TLC, IR, and 1H NMR spectroscopy. Depending on the chosen reactants, students observe both substitution and elimination products, or in some cases, no reaction at all. Therefore, data interpretation is an important component of this experiment. Students must determine the composition of their product mixtures by comparison to starting materials. The structures of expected and unexpected products must be elucidated and justified mechanistically. Our students perform this experiment prior to the investigation of elimination reactions in the lecture, which adds a discovery element. This experiment can be performed in two three-hour lab periods; however, advance preparation is required for the synthetic design of an assigned target.

A Multistep Synthesis for an Advanced Undergraduate Organic Chemistry Laboratory

A three-step procedure appropriate for an advanced-level undergraduate organic chemistry laboratory course has been developed for the synthesis of 5-(2-sulfhydrylethyl)salicylaldehyde. Two compounds, namely, 4-(2-iodoethyl)phenol and 5-(2-iodoethyl)salicylaldehyde, are isolated as intermediates from the first two steps of the method. A Grignard reagent is employed as a critical reactant for the synthesis. Several important laboratory techniques, such as TLC, column chromatography, and recrystallization, are emphasized. Spectrometric methods, including GC–MS and NMR spectroscopy, are used to identify the final product as well as the intermediates. Since each step of the procedure involves two or more hours of refluxing, parts of this experiment can be interspersed with other laboratory activities.

Microwave-Assisted Synthesis of a Natural Insecticide on Basic Montmorillonite K10 Clay. Green Chemistry in the Undergraduate Organic Laboratory

A microwave-assisted, one-pot synthesis of a naturally occurring insecticide on basic Montmorillonite K10 is described. The reaction is suitable for incorporation into the undergraduate organic chemistry laboratory course and represents a practical example of green chemistry. The described synthesis employs naturally benign, base-washed Montmorillonite K10 clay as a heterogeneous catalyst, is carried out under solvent-free conditions in a commercial-grade microwave oven, and features several interesting mechanistic considerations, including an electrophilic aromatic addition, dehydration, and intramolecular hetero-Diels–Alder cyclization.

Derivatization of Fullerenes: An Organic Chemistry Laboratory

Fullerene chemistry is a rapidly expanding research field that has grown immensely over the past decade. However, little fullerene chemistry is being incorporated into undergraduate lectures or laboratories, and there have only been two contributions in this Journal concerning this chemistry. With this in mind, two undergraduate organic chemistry laboratories were developed detailing the synthesis of fullerene derivatives, using the Bingel (carbene insertion) and Prato (1,3-dipolar addition) protocols. These experiments are appropriate for a second-semester organic chemistry laboratory. The experiments not only introduce fullerene chemistry, but they emphasize and reinforce key techniques including refluxing, IR, 1H NMR, UV–vis, TLC, and column chromatography.

Atualizando a química orgânica experimental da licenciatura

The present contribution describes three different modern experiments for possible adoption in undergraduate organic chemistry laboratories. These are: 1. electrocatalytic hydrogenation of benzaldehyde to benzyl alcohol; 2. identification of three volatile components, obtained from pineapple fruit, by mass spectrometry and 3. microwave mediated fast synthesis of N-(p-chlorophenyl)phthalamic acid from phthalic anhydride and p-chloroaniline under solvent-free conditions. The experiments can be executed in a short period of time, putting the undergraduate student in contact with a variety of topics in organic chemistry and several techniques of analysis, showing multidisciplinarity in organic chemistry.

EHPnet: Greener Education Materials for Chemists

Vol. 113, No. 11 EnvironewsOpen AccessEHPnet: Greener Education Materials for Chemists Erin E. Dooley Erin E. Dooley Search for more papers by this author Published:1 November 2005https://doi.org/10.1289/ehp.113-a737AboutSectionsPDF ToolsDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InReddit Green chemistry aims in part to help clean up chemical processing by reducing or eliminating toxic elements from production and use. One university at the forefront of the movement is the University of Oregon, which has developed a website, Greener Education Materials for Chemists (GEMS), to educate teachers on introducing green chemistry concepts to their students. Although the site, located at http://greenchem.uoregon.edu/gems.html, currently contains only materials for university-level education, the developers hope to eventually include content for K–12 teachers.The site consists of a database of print resources, which visitors can search using free text or by selecting search terms from seven categories, including chemistry concepts, laboratory techniques, green chemistry principles, and chemistry sub-disciplines. Each item in the database has an overview that summarizes its content and its connection to green chemistry as well as contact information for the person that contributed the material to the database.The different types of material that are currently available on the site, which is partially funded by the National Science Foundation, include laboratory exercises, lecture materials, course syllabi, and multimedia content. To aid educators in determining which materials best suit their needs, threaded discussions will soon be included for each item. Here educators will be able to discuss how they integrated materials into their lesson plans and relate their success in using them.The site, unveiled in June 2005 at an American Chemical Society meeting, was developed by a partnership between the university’s Green Chemistry Group and Center for Educational Technologies. Students and high school teachers were involved in the design of the site, as were more than 100 college instructors who attended national green chemistry education workshops at the university. The site’s developers have provided information on the site advising people how to contribute material to the database. They are also looking for educators to evaluate materials, test laboratory procedures, and adapt content for varying age groups. The developers want the web-site to be as inclusive as possible so it can serve as many grade levels and subject areas as possible.A link to information about the university’s Green Chemistry Center is sited in the toolbar at the top of the homepage. Here visitors can find an overview of the program’s work in developing undergraduate green chemistry curricula, the history of the program, and media coverage. A description of Green Organic Chemistry: Tools, Strategies and Laboratory Experiments, a textbook/laboratory manual released in 2004 for the undergraduate organic chemistry laboratory, is available from this page as well.FiguresReferencesRelatedDetails Vol. 113, No. 11 November 2005Metrics About Article Metrics Publication History Originally published1 November 2005Published in print1 November 2005 Financial disclosuresPDF download License information EHP is an open-access journal published with support from the National Institute of Environmental Health Sciences, National Institutes of Health. All content is public domain unless otherwise noted. Note to readers with disabilities EHP strives to ensure that all journal content is accessible to all readers. However, some figures and Supplemental Material published in EHP articles may not conform to 508 standards due to the complexity of the information being presented. If you need assistance accessing journal content, please contact [email protected]. Our staff will work with you to assess and meet your accessibility needs within 3 working days.

Generation, Isolation, and Characterization of a Stable Enol from Grignard Addition to a Bis-Ester. A Microscale Experiment for the Undergraduate Organic Chemistry Laboratory

A microscale experiment for the undergraduate organic chemistry laboratory that consists of preparing and characterizing an α-ketoester and its corresponding, remarkably stable enol form, has been developed. The reaction is that of a Grignard reagent with a bis-ester. A difference in reaction temperature is responsible for the selective generation of the α-ketoester and the enol ester. Analysis of spectral data (1H NMR and IR) and a knowledge of organic reactions allows the students to determine the detailed structure of the two reaction products and also to suggest a mechanism for their formation. This experiment introduces students to the concept of stability of the tetrahedral intermediate in acyl-transfer reactions. It also gives them a taste of the unexpected.

A Green Starting Material for Electrophilic Aromatic Substitution for the Undergraduate Organic Laboratory

Traditional experiments in the undergraduate organic chemistry laboratory involve the use of hazardous organic materials. Substitution of alternative green procedures wherever possible reduces organic waste and allows students to consider the need for environmentally sound chemistry. A green electrophilic aromatic substitution reaction (EAS), nitration of tyrosine, has been developed for use in the undergraduate laboratory. This reaction allows students to consider the varied aspects of EAS including activating and deactivating groups and o, p, m directors in a green environment. Product characterization can be accomplished by melting point, UV, or NMR.

Benzoin Condensation: Monitoring a Chemical Reaction by High-Pressure Liquid Chromatography

High-pressure liquid chromatography was successfully introduced in the undergraduate advanced organic chemistry laboratory to reinvestigate the cyanide-catalyzed condensation of benzaldehyde to benzoin. In addition to an increase in overall yield and purity of the product over the existing procedure the experiment provided the students with a practical hands-on introduction to modern HPLC and its application in process optimization.

The Synthesis and Isolation of N-tert-Butyl-2-phenylsuccinamic Acid and N-tert-Butyl-3-phenylsuccinamic Acid. An Undergraduate Organic Chemistry Laboratory Experiment

This experiment, which demonstrates that two isomeric products are obtained when an unsymmetrical anhydride is reacted with a nucleophile and that these isomers are easily separated based on their difference in acidity, is useful in introducing the topic of carboxylic acid derivatives into the organic chemistry laboratory.