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ERIC Number: EJ853492
Record Type: Journal
Publication Date: 2009-Sep
Pages: 6
Abstractor: As Provided
Reference Count: 39
ISSN: ISSN-0021-9584
The Metolachlor Herbicide: An Exercise in Today's Stereochemistry
Mannschreck, Albrecht; von Angerer, Erwin
Journal of Chemical Education, v86 n9 p1054-1059 Sep 2009
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 [superscript 1]H 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. (Contains 3 figures, 2 schemes, 1 table, and 1 note.)
Division of Chemical Education of the American Chemical Society. Subscription Department, P.O. Box 1267, Bellmawr, NJ 08099-1267. Tel: 800-691-9846; Tel: 856-931-5825; Fax: 856-931-4115; e-mail:; Web site:
Publication Type: Journal Articles; Reports - Descriptive
Education Level: Higher Education
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A