Revision of an enamine synthesis; the preparation and reactions of 2-morpholinoisoflav-3-ene.

The condensation of $\text{N}$-styrylmorpholine with salicylaldehyde does $\text{not}$ give a product that can be oxidised to isoflavone; the product is $\text{N}$-morpholino-isoflav-3-ene which can be used to prepare other compounds related to isoflavan and upon oxidation gives 3-phenylcoumarin.