Conversions of Coumarins Accompanied by Intermediate Opening and Recyclization of the Lactone Ring. 2. Study of the Interaction of Malonic Acid Hydrazide and Amide Derivatives with 3-Acyl(3-cyano, 3-ethoxycarbonyl)Coumarins
Reaction between the N,N′-diisopropylidene and N,N′-diacetyl derivatives of malonic acid dihydrazide and 3-acyl(3-cyano, 3-ethoxycarbonyl)coumarins under the conditions of the Michael reaction lead to the formation of N′-isopropylidene and N′-acetyl derivatives of coumarin-3-carboxylic acid hydrazide. Ethoxycarbonylacethydrazide reacts in an analogous manner. Special features have been studied of the interaction of malonic acid amide derivatives with unsubstituted coumarin and with coumarins containing electron-withdrawing groupings in position 3 of the ring.