Selenium-Containing Heterocycles from Isoselenocyanates: 4-Methylselenazole Derivatives from the Reaction with Malononitrile and Propargyl Chloride

Aryl isoselenocyanates 1 react with malononitrile (6a) and propargyl chloride (8) in DMF in the presence of Et3N to give the corresponding 2‐(3‐aryl‐2,3‐dihydro‐4‐methyl‐1,3‐selenazol‐2‐ylidene)malononitriles 12 as major products. The analogous reaction takes place with benzoylacetonitrile (6f) instead of 6a. In some cases, the corresponding noncyclic 2‐[(arylamino)(prop‐2‐ynylselanyl)methylidene]malononitriles 9 were obtained as minor products. The structures of 9e and 11a have been established by X‐ray crystallography.