Prev. Article Next Article Table of Contents

Lab-Expt

Mosher Amides: Determining the Absolute Stereochemistry of Optically-Active Amines

Your current credentials do not allow retrieval of the full text.

Purchase the full-text

PDF/HTML,
figures/images,
references and tables,
(where available)

Damian A. Allen , Anthony E. Tomaso Jr. and Owen P. Priest

Department of Chemistry, Northwestern University, Evanston, IL 60208

David F. Hindson and Jamie L. Hurlburt

Department of Chemistry, Hobart and William Smith Colleges, Geneva, NY 14456

J. Chem. Educ., 2008, 85 (5), p 698

DOI: 10.1021/ed085p698

Publication Date (Web): May 1, 2008

Abstract

The use of chiral reagents for the derivatization of optically-active amines and alcohols for the purpose of determining their enantiomeric purity or absolute configuration is a tool used by many chemists. Among the techniques used, Mosher's amide and Mosher's ester analyses are among the most reliable and one of the most often used. Despite this, these techniques are rarely introduced in the undergraduate organic laboratory. In this experiment teams of students are given optically-pure amines of known structure but unknown stereochemistry. One half of the team derivatizes a sample of the amine with optically-pure (R)-Mosher's acid chloride and the other half of the team derivatizes a sample of the amine with optically-pure (S)-Mosher's acid chloride. The resulting amide diastereomers can be analyzed by ¹H NMR spectroscopy and, using Mosher's model, distinguished from one another. Through careful analysis the students can determine the absolute configuration of their starting amine. Sample reactions are presented as well as spectral data for 18 Mosher amides that have been used in this experiment.

Keywords (Audience):

Second-Year Undergraduate

Keywords (Domain):

Laboratory Instruction

Keywords (Feature):

The Microscale Laboratory

Keywords (Pedagogy):

Collaborative / Cooperative Learning

Keywords (Subject):

Amides

View: Hi-Res PDF | PDF w/ Links

Citing Articles

View all 2 citing articles

Citation data is made available by participants in CrossRef's Cited-by Linking service. For a more comprehensive list of citations to this article, users are encouraged to perform a search in SciFinder.

This article has been cited by 2 ACS Journal articles (2 most recent appear below).

A Wet-Lab Approach to Stereochemistry Using ³¹P NMR Spectroscopy
Owen S. Fenton and Bianca R. Sculimbrene
Journal of Chemical Education2011 88 (5), 662-664
- A Wet-Lab Approach to Stereochemistry Using ³¹P NMR Spectroscopy
  Owen S. Fenton and Bianca R. Sculimbrene
  Journal of Chemical Education2011 88 (5), 662-664
  Understanding stereochemistry is an important and difficult task for students to master in organic chemistry. In both introductory and advanced courses, students are encouraged to explore the spatial relationships between molecules, but this exploration ...
  Abstract | Full Text HTML | Hi-Res PDF | PDF w/ Links
Using NMR To Probe the Regio- and Stereochemistry of the Hydration of 1-Hexene
Shahrokh Saba, Donald D. Clarke, Christa Iwanoski, and Thomas Lobasso
Journal of Chemical Education2010 87 (11), 1238-1241
- Using NMR To Probe the Regio- and Stereochemistry of the Hydration of 1-Hexene
  Shahrokh Saba, Donald D. Clarke, Christa Iwanoski, and Thomas Lobasso
  Journal of Chemical Education2010 87 (11), 1238-1241
  This undergraduate organic laboratory experiment complements previously described and popular experiments on hydration of 1-hexene where students experimentally establish the Markovnikov regioselectivity of alkene hydration. In this experiment, students ...
  Abstract | Full Text HTML | Hi-Res PDF | PDF w/ Links

Tools

SciFinder Links

Explore by:

Author of this Article Any Author Research Topic

History

Received: August 03, 2009

Select a CAS section from the 5 main topical divisions below:

Lab-Expt

Mosher Amides: Determining the Absolute Stereochemistry of Optically-Active Amines