Selenium-containing heterocycles from isoselenocyanates: Base-catalyzed reaction of malononitrile with phenyl isoselenocyanate and bromoacetonitrile or alpha-halogenated ketones

Abstract

The reaction of phenyl isoselenocyanate (1a) with malononitrile (= propanedinitrile) in DMF in the presence of Et3N leads to the intermediate ketene N,Se-hemiacetal 6a, which can be trapped with bromoacetonitrile or a-halogenated ketones 12a and 12b (Scheme 3). The products are [(alkylseleno)-(phenylamino)methylene]malononitriles 10 and 13, which are obtained in good yield. In the case of the (2-oxoalkyl)seleno derivatives 13, they are in equilibrium with the cyclic hemiacetals 14. Chemical and spectroscopic evidence for the structure Show more