Synthesis of new hybrid structures based on 3H-furanone and 1H-pyrazole

Introduction

(Het)arylmethylidene derivatives of furan-2(3H)-ones rightfully occupy a special place in modern organic chemistry, since they are present in various natural compounds and also provide building blocks in the synthesis of various potential biologically active compounds. From this point of view, hybrid systems containing furan-2(3H)-one and chromen-4(4H)-one fragments are promising for research, modification of which will further expand the spectrum of biological activity of new hybrid structures

Experimental details

3-((5-(2-hydroxyphenyl)-1H-pyrazol-4-yl)methylene)-5-arylfuran-2(3H)-ones were synthesized by the reaction (E)-3-((2-oxo-5-arylfuran-3(2H)-ylidene)methyl)-4H-chromen-4-ones with excess hydrazine monohydrate in ethyl alcohol in good yields. The composition and structure of all compounds were characterized by a complex of spectroscopic methods (IR, NMR).

Results and Discussion

Taking into account the structure of the reaction products, it can be assumed that an attack of hydrazine occurs at the C₂-O bond of the chromen-4-one fragment, accompanied by ring opening with the formation of an enamine fragment; further attack of the amino group at the C=O group of the original chromen-4-one leads to the formation of a pyrazole cycle in the final reaction products.

Acknowledgments

This work received financial support from the Foundation for Assistance to Small Innovative Enterprises (FASIE) (grant no. 18695GU/2023 to Arzyamova E.M.).