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

Abstract

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.Keywords: 3-acyl(3-cyano, 3-ethoxycarbonyl)coumarins, malonic acid hydrazide and amide derivatives, mass spectrometric study of reaction products and reaction mixtures, opening and recyclization of the coumarin lactone ring, Michael reaction.Study of the interaction of 3-acyl(ethoxycarbonyl)coumarins with malonic acid dihydrazide under the conditions of the Michael reaction has shown that this reaction occurs analogously to the conversion of 3-acyl(ethoxycarbonyl)coumarins into 3-cyanocoumarins discovered by us previously [2, 3] with the formation of coumarin-3-carboxylic acid hydrazide 2.The resulting hydrazide 2, in its turn, interacts with the initial 3-acyl(ethoxycarbonyl)coumarins with the formation of salicylidene derivatives of coumarin-3-carboxylic acid hydrazides 4. The composition of the products essentially depends on the structure of the initial coumarin. In the case of coumarins unsubstituted in the benzene ring, and also their 6-methyl (6-Br) or 8-OMe derivatives, the salicylidene derivatives of coumarin-3-carboxylic acid hydrazides 4a-d predominate among the reaction products [4]. In the case of 3-ethoxycarbonyl(acetyl)coumarins the formation of the corresponding N,N'-biscoumarinoyl-2-hydrazines 3a-c was noted. These compounds are formed in insignificant amount and were not isolated in the pure state. Their presence in the reaction mixture was established by the presence in the mass spectra of the corresponding peaks for the molecular ions.

3-Acyl(aroyl)coumarins as synthon in heterocyclic synthesis

“…84 Furthermore, interaction of 3-substituted coumarin derivatives 1 with malonic acid dihydrazide 159 under Michael reaction conditions showed the conversion of 1 into coumarin-3-carboxylic acid hydrazide 160 (Scheme 28). 85 When the resulting hydrazide 160 was reacted with 3-substituted coumarin derivatives 1, coumarin-3-carboxylic acid hydrazone derivatives 161 were obtained (Scheme 28). 85…”

“…85 When the resulting hydrazide 160 was reacted with 3-substituted coumarin derivatives 1, coumarin-3-carboxylic acid hydrazone derivatives 161 were obtained (Scheme 28). 85…”