Synthesis of Aryl-Substituted 2,4-Dinitrophenylamines: Nucleophilic Aromatic Substitution as a Problem-Solving and Collaborative-Learning Approach

Santos, E.; García, Irma Cruz Gavilán; Gómez, Eva Florencia Lejarazo; Vilchis‐Reyes, Miguel A.

doi:10.1021/ed100392e

Cited by 12 publications

(6 citation statements)

References 11 publications

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“…The assignment is split into two parts: In Part 1, students evaluate the sustainability of the provided S N Ar procedure, and in Part 2, the S N Ar procedure is compared with the experimental class data for the B–H procedure ( vide infra ). The conditions for the S N Ar reaction are modified from literature procedures − and given to students in the form of a synthetic outline. The amounts of reagents and solvents are stated in a table for students to know the exact quantities of materials used.…”

Section: Assignment Backgroundmentioning

confidence: 99%

Comparing Industrial Amination Reactions in a Combined Class and Laboratory Green Chemistry Assignment

et al. 2018

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This article describes a comparative assignment developed for a third-year undergraduate organic synthesis course involving a combined laboratory experiment and class exercise. In this assignment, students compare the sustainability of two industrial amination reactions to form the same target molecule (4-(n-hexylamino)benzonitrile): a nucleophilic aromatic substitution procedure (S N Ar) provided in the class exercise, and a Buchwald−Hartwig (B−H) amination procedure completed in the laboratory. The assignment is structured using a "case-study" format to provide appropriate context. Students use industrial solvent and reagent substitution guides, complete process mass intensity calculations, and apply the Twelve Principles of Green Chemistry to compare and contrast the S N Ar and B−H reactions. They finally recommend a preferred reaction procedure after considering multiple sustainability concepts in their analyses. The assignment is highly adaptable as different industry guides may be used and the S N Ar reaction procedure is easily modified. Ultimately, students learn to apply sustainable chemistry principles to industrially relevant reactions, an important skill for their future careers.

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Section: Assignment Backgroundmentioning

confidence: 99%

Comparing Industrial Amination Reactions in a Combined Class and Laboratory Green Chemistry Assignment

et al. 2018

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“…Even though aryl halides are generally inert to nucleophilic substitution, aryl halides that contain electron withdrawing groups such as a nitro group ortho or para to the halogen undergo nucleophilic aromatic substitution. Variations of S N Ar experiments have been developed for chemistry education in the past, each with distinct value. − For example, Santos et al developed a problem-solving and collaborative-learning approach to the synthesis of aryl-substituted 2,4-dinitrophenylamines to facilitate higher retention and encourage students to interpret and draw conclusions from data themselves . Avila et al redesigned the synthesis of 2-ethylbenzoic acid into a five-step microscale experiment .…”

Section: Introducing the Experimentsmentioning

confidence: 99%

A Green Nucleophilic Aromatic Substitution Reaction

Abraham

2020

J. Chem. Educ.

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This paper revisits the tie-dyeing process through a bioinspired and safer alternative to nucleophilic aromatic substitution (SNAr) reactions for an introductory organic chemistry laboratory. The simple and straightforward experiment provides students with an opportunity to gain practical experience in conducting a chemical reaction in a real-world context while applying concepts of design for biodegradability and reusability. The water-soluble reactive dye that replaces the use of a conventional SNAr substrate does not require any heavy metals, toxic substances, or mordants but utilizes a much less toxic and safer sodium carbonate to generate the cellulosate nucleophile. This reaction generates no waste, and the end-product, the tie-dyed T-shirt, is reusable and biodegradable. Through this experiment, students can see connections between chemistry and environmental health while gaining a practical insight into dyeing chemistry, making use of a systems thinking approach. This experiment serves not only to employ safer alternatives to hazardous chemicals in the undergraduate organic chemistry laboratory but also to educate students to recognize the relevance and importance of applying green chemistry wherever it is possible, emphasizing life cycle thinking and stewardship.

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“…Electrophilic aromatic substitution reactions are a cornerstone of organic chemistry laboratory experiments emphasizing the understanding of key concepts such as reaction mechanisms, aromatic directing groups, resonance and inductive effects, and regioselectivity. Many of these reactions require the use of toxic and hazardous reagents − and do not follow current trends in undergraduate laboratory experiments of implementing green chemistry principles . This experiment was designed to utilize green methods to complete a two-step synthesis that included an electrophilic aromatic substitution.…”

Section: Introductionmentioning

confidence: 99%

1-Dimensional Selective Nuclear Overhauser Effect NMR Spectroscopy To Characterize Products from a Two-Step Green Chemistry Synthesis

2018

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One dimensional (1-D) 1H and 13C NMR experiments are common tools used in undergraduate organic laboratories to characterize synthesized molecules. However, 1-D NMR spectra cannot always provide unambiguous structure determination. In research laboratories, advanced NMR spectroscopy methods are employed for structural assignments of synthesized molecules. This experiment is designed to introduce undergraduate students to the application of an advanced method of 1H NMR spectroscopy, the 1-D selective nuclear Overhauser effect (NOE) experiment, to fully characterize the structure of two compounds. The experiment features a two-step green chemistry synthesis to produce the two compounds. In the first step of the synthesis, 4-methylaniline (para-toluidine) is acetylated to form 4′-methylacetanilide (para-acetotoluidide). The 1-D selective NOE method is used to identify the two different methyl groups present in 4′-methylacetanilide and to assign the aromatic protons. For the second step of the synthesis, bromination of the aromatic ring of 4′-methylacetanilide is accomplished using Oxone and ammonium bromide in an aqueous solvent. The 1-D selective NOE method is applied to determine the regioselective product of the bromination reaction. The 1-D selective NOE experiment is readily accessible and easily implemented. Successful interpretation of the 1-D selective NOE results leaves students confident in making structural assignments that would otherwise be based solely on theory or software prediction.

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Synthesis of Aryl-Substituted 2,4-Dinitrophenylamines: Nucleophilic Aromatic Substitution as a Problem-Solving and Collaborative-Learning Approach

Cited by 12 publications

References 11 publications

Comparing Industrial Amination Reactions in a Combined Class and Laboratory Green Chemistry Assignment

Comparing Industrial Amination Reactions in a Combined Class and Laboratory Green Chemistry Assignment

A Green Nucleophilic Aromatic Substitution Reaction

1-Dimensional Selective Nuclear Overhauser Effect NMR Spectroscopy To Characterize Products from a Two-Step Green Chemistry Synthesis

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