JCE Online Journal of Chemical EducationDivision of Chemical Education, American Chemical SocietyAmerican Chemical Society
 | Subscriptions  | Software Orders  | Support  | Contributors  | Advertisers  | 

JCE Print
   Current Issue
 Previous Issues
 Supplements
 Search JCE Index

JCE Digital Library
   JCE DLib Catalog
   ChemInfo
 Data-Driven Exercises
 DigiDemos
 Featured Molecules
 LivTexts
 LrnCom
 QBank
 SymMath
 WebWare

JCE Software
   Latest Releases
 Software & Video
 Downloads
 Support

Only@JCE Online
   JCE Online Store
 JCE HS CLIC
 JCE Discussion Forums
   Biographical Snapshots
 ChemEd Resource Shelf
 Hal's Picks
 Project Chemlab
 Reviewed WWW Sites
 "Web-Ed" Articles

About JCE
   Features
 Publications
 Operations
 Outreach
 Contact Us


  Home > JCE Print > Journal of Chemical Education > Issues > 2009  > September  >
In the Classroom
The Metolachlor Herbicide: An Exercise in Today's Stereochemistry
Albrecht Mannschreck
Department of Organic Chemistry, University of Regensburg, D-93040 Regensburg, Germany

Erwin von Angerer
Department of Pharmacy, University of Regensburg, D-93040 Regensburg, Germany

Cover
September 2009
Vol. 86 No. 9
p. 1054
Abstract
Metolachlor is one of the most widely used agents registered for the protection of many cultivated plants against weeds. Because of axial and central chirality, this molecule forms four stereoisomers, the investigation of which by 1H NMR and chromatography is described. It is shown that the isomers do not interconvert at room temperature. Non-enantioselective and enantioselective preparations on industrial scales, developed by the Syngenta Company, are given, including the composition of the catalyst used for an enantioselective hydrogenation step. The bioactivities of the four separated species are discussed. The mixture of the two stereoisomers with stronger biological effects, commonly designated (S)-metolachlor, has largely replaced the 1:1:1:1 mixture in practical agriculture. The load to the environment diminishes by using a lower dosage of (S)-metolachlor instead of a higher dosage of the 1:1:1:1 mixture. The present article exemplifies several general stereochemical aspects that are placed together in the conclusion of the article.

See JCE Featured Molecules.
More Information
*
Citation
Mannschreck, Albrecht; von Angerer, Erwin. J. Chem. Educ. 2009, 86, 1054.
*
Keywords
Agricultural Chemistry; Bioorganic Chemistry; Chirality / Optical Activity; Chromatography; Diastereomers; Enantiomers; NMR Spectroscopy; Organic Chemistry; Second-Year Undergraduate; Stereochemistry; Synthesis; Textbooks / Reference Books; Upper-Division Undergraduate
*
History
Created:
Last Updated:
7/28/2009
7/28/2009
<< Previous Article Table of Contents Next Article >>
  Home > JCE Print > Journal of Chemical Education > Issues > 2009  > September  > Page 1054


Subscriptions
 Subscription Info
 Order Forms

JCE HS CLIC

Our Secondary School editors work hard to distill all the JCE materials to produce a fraction of particular interest to high school teachers. We call it CLIC.
 JCE HS CLIC

Contributions Welcome
JCE welcomes your submission
 Contributors' Corner

Advertisers
In recent years we have worked hard to better match our advertisers with our readers. When shopping for chemistry education materials, visit our advertisers' WWW sites first.
 Recent Advertisers

Be An Ambassador
Take JCE along on your outreach missions. Copies of the Journal, guest access to JCE Online, our publications catalog, and more are available for your participants.
 Outreach with JCE

Comments to
jceonline@chem.wisc.edu		 Copyright © Division of Chemical Education, Inc., American Chemical Society.
All rights reserved.