Abstract Reactions of 5-substituted furan-2 (3 H)-ones with ethylenediamine, 2- aminoethanol, and o-aminophenol do not stop at the stage of formation of the corresponding 4-oxoalkanoic acid amides but lead to new bi-and tricyclic structures as a result of double intramolecular cyclodehydration.
![7a-propyl-2,3,6,7-tetrahydro-1H-pyrrolo[1,2-a]imidazol-5-one结构式](https://image.chemsrc.com/caspic/056/114543-38-3.png)