Acidic Ionic Liquid-catalyzed Synthesis of Pyrano[4,3-b]pyran-5(4H)-ones using 4,4,4-trifluoro-1-phenylbutane-1,3-dione as a Building Block

Aims: synthesis of pyrano[c-2,3]chromens with Ionic Liquid catalyst with simple method. Background: Synthesis of pyrano[c]coumarins has a special place in the structure due to two bioactive compounds in its structure and attracts a great deal of attention in this research work, it has been attempted to attach chromatically valuable skeletons to them and synthesize the pyrano [c] coumarines, which can potentially have high biological properties. For this purpose, electrophilic β-ketoester ringing in the presence of ionic liquid catalysts was used. While optimizing the catalyst recovery, it is possible to synthesize several coumarine pyrano[ c]derivatives with high yield. Objective: This paper describes an efficient procedure for the multi-component reaction of aromatic aldehydes, 4,4,4-Trifluoro-1-phenyl-1,3-butanedione and 4-hydroxycoumarinwhich catalyzed by Ioniq liquid (OlmDSA), at room temperature. This catalyst was synthesized with new simple procedure. This protocol has advantages of simplicity, mild condition and high yield. Materials and Methods: After formation of a new stain corresponding to the alkene intermediate, 4-hydroxy coumarin (1 mM) was added. The reaction was progressed by thin layer chromatography in a 1: 2 ratio solvent containing ethyl acetate and hexane. The reaction mixture was then stirred for one hour. After the reaction was complete, the catalyst was first removed by washing. Ethanol was then added to the reaction residue and washed and finally filtered. The residual solid on the filter paper after drying was considered as the product and was taken to confirm. its structure, melting point and spectra. The following is a general overview of the reaction. Results and Discussion: In addition to the advantages mentioned for this tri-component reaction, the conservation of the coumarin ring is very important in this research design because it is formed in many of the reported open reactions and phenolic ring. Conclusion: The benefits of this work include simple reaction steps, review of reaction progress by TLC chromatography, simple separation of the catalyst by washing and reuse for three times without any reduction in yield and high reaction yield.