Synthesis and transformations of 4𝐻-chromene 4-hydroxy-2𝐻-pyran-2-one and 4𝐻-chromene 4-hydroxycoumarin conjugates

Journal of Chemical Sciences

Venkata Swamy Tangeti¹  H Surya Prakash Rao1¹ 

[1] Department of Chemistry, Pondicherry University, Pondicherry 605 014, India$$

关键词: 4𝐻-Chromenes;    4-hydroxy-2𝐻-pyran-2-ones;    hydroxycoumarins;    furo[3;    2-𝑐]coumarins.;   

DOI  :  

来源: Indian Academy of Sciences

【 摘 要 】

The reaction of 𝑁-methyl-4-(methylthio)-3-nitro-4𝐻-chromen-2-amine and its derivatives with 4-hydroxy-6-methyl-2𝐻-pyran-2-one in EtOH reflux for 5 min furnish 4-hydroxy-6-methyl-3-(2-(methylamino)-3-nitro-4𝐻-chromen-4-yl)-2𝐻-pyran-2-ones in quantitative yield. By extending EtOH reflux for 2 h, the 4𝐻-chromene 4-hydroxy-2-pyranone conjugates get converted into acetoacetyl coumarins. Similar reaction of 𝑁-methyl-4-(methylthio)-3-nitro-4𝐻-chromen-2-amine and its derivatives with 4-hydroxycoumarin in EtOH reflux furnish 4-hydroxy-2'-(methylamino)-3'-nitro-2𝐻,4'𝐻-3,4'-bichromen-2-ones. In contrast to earlier system, prolonging reflux in EtOH or in 𝑛-PrOH reflux the product gets transformed into trans-ethyl 3-(2-hydroxyaryl)-4-oxo-3,4-dihydro-2𝐻-furo[3,2-c]chromene-2-carboxylates. Thus, facile synthesis and characterization of 4𝐻-chromene 4-hydroxy-2-pyrone, 4𝐻-chromene 4-hydroxycoumarin conjugates, acetoacetyl coumarins and trans2,3-disubstituted dihydrofuro[3,2-c]coumarins is described.

【 授权许可】

Unknown