1-ethyl-4-hydrazino-1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid, ethyl ester → 8-furfuryl-2-methyl-4H-pyrazolo[1,5-a]pyrazolo-[4',3':5,6]pyrido[3,4-e]pyrimidin-5(8H)-one

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Reaction Steps

By substituting 4-hydrazino-1-furfurylpyrazolo[3,4-b]pyridine-5-carboxylic acid, ethyl ester for the 1-ethyl-4-hydrazino-1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid, ethyl ester in Example 1(a) and proceeding as in parts (a) and (b), 8-furfuryl-2-methyl-4H-pyrazolo[1,5-a]pyrazolo[4',3':5,6]pyrido[3,4-e]pyrimidin-5(8H)-one is obtained. This compound is now processed as in Example 1, part (c), substituting bromobenzene for the methyl iodide. A small amount of copper catalyst is added to obtain 1-furfuryl-2-methyl-4-phenyl-4H-pyrazolo[1,5-a]pyrazolo[4',3':5,6]pyrido[3,4-e]pyrimidin-5(8H)-one.

Provenance & Evidence