The bacterial oxidation of nicotinic acid. N-formylmaleamic and N-formylfumaramic acids.

N-Formylmaleamic acid, a probable intermediate in the bacterial metabolism of nicotinic acid, has been synthesized by photoisomerization of its trans isomer, N-formylfumaramic acid. The compound previously reported to be N-formylmaleamic acid has been shown to be N-formylfumaramic acid.