Synthesis of Functionalized 4H-Pyrano[3,2-c]pyridines from 4-Hydroxy-6-methyl-2-pyridone and Their Reactions. Unexpected New Routes to 3,3′-Benzylidenebis[4-hydroxy-6-methyl-2(1H)-3-pyridinone]s

• DOI: 10.1246/bcsj.70.1625
• Publication Date: 2006-06-13T05:51:23Z
• Authors: Ramadan Ahmed Mek...; Nabil Helmi Mohamed; Kamal Usef Sadek
• Keywords: Piperidine; 2-Pyridone; Indoline

Abstract The reaction of 4-hydroxy-6-methyl-2-pyridone 1 with benzylidenemalononitriles in an ethanolic solution containing a catalytic amount piperidine and α-cyanoacrylic esters pyridine affords the corresponding 4H-pyrano[3,2-c]pyridines. However, it’s 3-(cyanomethylene)-2-indolinones gives either 2-amino-3-quinolinecarbonitriles or ethyl 2-amino-5′,6′-dihydro-7′-methyl-2,5′-dioxospiro-[indoline-3,4′-[4H]-pyrano[3,2-c]pyridine-3′-carboxylate. In contrast, 3-aryl-2-cyano-2-propenethioamides 3,3′-benzylidenebis[4-hydroxy-6-methyl-2(1H)-3-pyridinone]s. obtained 4H-pyrano[3,2-c]pyridines acetic anhydride fused system.