Synthesis and reactions of 4-Hydroxy-2(1H)-pyridones with thienyl and pyridyl substituents in position 6 starting with azomethines and malonates

The reaction of 4 with substituted diethyl malonates 5a , or “magic malonates” (bis-2,4,6-trichlorophenylmalonates 5b ) leads to 4-hydroxy-2(1H)-pyridones 6. The azomethines 4 are prepared via the Strecker compounds 3 starting with methyl ketones 1 , anilines, and potassium cyanide. Chlorination of pyridones 6 with sulfuryl chloride leads to compounds 7 while nitration gives 9.