"Double Unknown" Microscale Preparation and COSY Analysis of an Unknown Ester: An Introductory 2D-NMR Experiment

Abstract

2D-NMR experiments are becoming more commonplace for organic analysis and promise to become as routine for chemists of this decade as 1D-NMR experiments were for chemists of the 1970's. However, undergraduate students seldom if ever are exposed to such experiments despite the increasing availability of high-field, superconducting magnets, more powerful computers, and menu driven software that is extremely friendly. This article outlines an experiment that integrates NMR into the organic teaching laboratory in a way designed to highlight the power of the technique and not merely to confirm the identity of known substances.

Developing and Implementing Multioutcome Experiments in Undergraduate Teaching Laboratories To Promote Student Ownership of the Experience: An Example Multioutcome Experiment for the Oxidation of Alcohols

“…Compared to traditional single-outcome procedures, the aforementioned variances allow more unique learning experiences to occur in the classroom and create a more synergistic relationship with the associated lecture presentation. ,,, An example of an MOE recently developed and implemented into the undergraduate organic instructional laboratory explores the oxidation of alcohols. This new MOE addresses the challenges previously mentioned and also specifically reinforces the utility of NMR spectroscopy by providing access to benchtop 1 H NMR technology to undergraduate students, thereby encouraging engagement and ownership of the experiment. ,,− Commonly used NMR instruments have high operation costs, requiring the use of cryogens and specially trained staff members. Since the advent of benchtop 1 H NMR technology, spectra of neat samples spiked with tetramethylsilane (TMS) are collected in a matter of seconds and processed within a few minutes using NMR processing software such as MestreNova or TopSpin.…”

Implementation of picoSpin Benchtop NMR Instruments into Organic Chemistry Teaching Laboratories through Spectral Analysis of Fischer Esterification Products

“…The Fischer esterification reaction and its application in multioutcome experiments has been studied for many years and is commonly included in organic chemistry laboratory curricula across the country. − The reaction produces an ester and water from a carboxylic acid and an alcohol, as shown in Figure . Because this reaction is reversible, Le Châtlier’s principle can be utilized to drive the reaction toward the desired product esters.…”

Scaffolding Students’ Skill Development by First Introducing Advanced Techniques through the Synthesis and 15N NMR Analysis of Cinnamamides

“…The instruction of NMR spectroscopy typically focuses on hydrogen, carbon, and a variety of two-dimensional (2D) NMR techniques for the elucidation of both natural − and synthetic − compounds. As a mainstay of introductory and advanced organic chemistry curricula, these techniques give students valuable experience in the molecular characterization of synthetic and naturally occurring compounds.…”