Reactions of chromone-3-carboxylic acid and chromone-3-carboxamides with cyanoacetic acid hydrazide

Chromone and chromone-3-carboxylic acid react with cyanoacetic acid hydrazide in the presence of NaOEt in boiling ethanol to form 6-(2-hydroxyphenyl)-1H-pyrazolo[3,4-b]pyridin-3(2H)-one (58-62% yields), whereas reaction between chromone-3-carboxamides and cyanoacetic acid hydrazide under the same conditions affords 1-amino-2,5-dioxo-2,5-dihydro-1H-chromeno[4,3-b]pyridine-3-carbonitriles (50-67% yields).