Reactions of 1-aminocyclopentenes with acyl aryldiazenes give 1:1 enaminic adducts or 1,3,4-oxadiazines. Isolation of these products was not always possible in the reactions of 1-(piperidin-1-yl)- and 1-(pyrrolidin-1-yl)-cyclopentene. Acidic hydrolysis gave 2-(N-acyl-N'-aryl)hydrazinocyclopentanones or 2-arylaminocyclopentenones, depending upon the amine moiety and the cyclic or open chain nature of the adducts.
