A Coumarin Mystery-The Case Of The Missing Methyl Groups

TCE

The Chemical Educator

ISSN: 1430-4171 (electronic version)

Table of Contents

Abstract Volume 14 Issue 3 (2009) pp 105-109

A Coumarin Mystery–The Case Of The Missing Methyl Groups

Laura M. Minea and Andrew P. Dicks*

Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, Canada, M5S 3H6, adicks@chem.utoronto.ca
Received August 7, 2008 Accepted May 5, 2009.

Published online: 6 June 2009

Abstract. This article describes a discovery-oriented undergraduate experiment positioned as a “mystery” in an upper-level mechanistic organic course at the University of Toronto. Students individually undertake a trivial synthetic reaction between an aromatic salicylaldehyde and 2,2-dimethyl-1,3-dioxane-4,6-dione (Meldrum’s acid), without being informed of the product structure. They work collaboratively during the reaction time to propose both a likely product and operative mechanism given the experimental conditions and physical observations made. Finally, students obtain spectroscopic information about their synthesized compound and justify whether their predictions were sound (or otherwise).

Key Words: Laboratories and Demonstrations; organic chemistry; reaction mechanisms; microscale synthesis; discovery-oriented experiments; collaborative learning; coumarins

(*) Corresponding author. (E-mail: adicks@chem.utoronto.ca)

Article in PDF format (53 KB) HTML format

Supporting Materials:

Laboratory notes for students (including an experimental procedure and post-lab questions), additional notes for instructors and product spectroscopic information (7-(diethylamino)-3-carboxycoumarin and 6-chloro-3-carboxycoumarin ¹H NMR spectra and assignments) are available in a Zip file (499 KB)