The chemistry of the Wender’s test for Dulcin

Francisco Sánchez-Viesca * and Reina Gómez

Department of Organic Chemistry, Faculty of Chemistry, National Autonomous University of Mexico, Mexico City (CDMX), Mexico.
 
Research Article
Open Access Research Journal of Chemistry and Pharmacy, 2023, 04(01), 001–004.
Article DOI: 10.53022/oarjcp.2023.4.1.0066
Publication history: 
Received on 10 May 2023; revised on 25 June 2023; accepted on 28 June 2023
 
Abstract: 
The reaction route of Wender’s test for Dulcin, p-phenetolecarbamide, is disclosed in this article. The many steps in this interesting oxido-degradation process are fully commented and the electron flow is given. Wender used fuming nitric acid as reagent. A violent reaction takes place; however, the test is safe due to the minute quantity employed of this sweetener. Further addition of phenol solution and sulphuric acid gives a blood-red colour. The reactions that occur are as follows: nitration of the ureido group, nitrous acid removal, nitrate formation, elimination of nitrous acid, nitroso group formation, separation of nitric acid and carbon monoxide, free radical degradation to p-benzoquinone imine, hydrolysis, and formation of red phenoquinone, the colour observed in the test.
 
Keywords: 
P-Benzoquinone imine; Free radicals; Nitrourea; Oxido-degradation; P-Phenetolecarbamide; Phenoquinone
 
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