Abstract Activated enol ethers derived from esters or the dinitrile of malonic acid, or from pentane-2, 4-dione were treated with hydrazine hydrate. The structures of the obtained products–pyrazoles 5–were studied with a focus on tautomerism and supramolecular structure. A reverse addition of the reagents led to the isolation of two novel products, namely bis-enehydrazines 6 with an unsymmetrical arrangement of the formally ...
