Allium ursinum
The analytical techniques used to study its pharmacology laid the groundwork for the testing of new anesthetic agents. Vinyl ether was first prepared in 1887 by Semmler from its sulfur substituted analogue, divinyl sulfide (obtained from the essential oil of "Allium ursinum" L.), by reaction with silver oxide. In 1899, Knorr and Matthes obtained low yields of vinyl ether by exhaustive methylation of morpholine.