We have synthesized and pharmacologically examined compounds of this series containing a phenacylidene substituent in position 5 of the oxazolidene ring. These compounds were synthesized by recycling 5-aryl-2, 3-dihydrofuran-2, 3-diones (I) upon reacting with cyanamides [i]. The reaction proceeds readily with a non-substituted cyanamide as well as with monoalkyl-and monoarylcyanamides with the formation of 5-phenacylidene-2-imino- ...