naa a22 4500 510734391 CHVBK 20180411083004.0 cr unu---uuuuu 180411e20130701xx s 000 0 eng 10.1007/s12039-013-0458-y doi (NATIONALLICENCE)springer-10.1007/s12039-013-0458-y Synthesis and transformations of 4 H -chromene 4-hydroxy-2 H -pyran-2-one and 4 H -chromene 4-hydroxycoumarin conjugates [Elektronische Daten] [H RAO, VENKATA TANGETI] 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. Graphical Abstract 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)-2Hpyran-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, we have found a facile synthesis of 4H-chromene 4-hydroxy-2-pyrone, 4H-chromene 4-hydroxycoumarin conjugates, acetoacetyl coumarins and trans 2,3-disubstituted dihydrofuro [3,2-c]coumarins. Indian Academy of Sciences, 2013 4 H -Chromenes nationallicence 4-hydroxy-2 H -pyran-2-ones nationallicence hydroxycoumarins nationallicence furo[3,2- c ]coumarins nationallicence RAO H. Department of Chemistry, Pondicherry University, 605 014, Pondicherry, India aut TANGETI VENKATA Department of Chemistry, Pondicherry University, 605 014, Pondicherry, India aut Journal of Chemical Sciences Springer India 125/4(2013-07-01), 777-790 0974-3626 125:4<777 2013 125 12039 https://doi.org/10.1007/s12039-013-0458-y text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s12039-013-0458-y text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- RAO H. Department of Chemistry, Pondicherry University, 605 014, Pondicherry, India aut NATIONALLICENCE 700 1- TANGETI VENKATA Department of Chemistry, Pondicherry University, 605 014, Pondicherry, India aut NATIONALLICENCE 773 0- Journal of Chemical Sciences Springer India 125/4(2013-07-01), 777-790 0974-3626 125:4<777 2013 125 12039 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer