Structural Determination of a Process Impurity in a Furan−Pyrrole Heteroatom Exchange Reaction
摘要:
Electron-deficient pyrrole (1) was derivatized by diazotization with p-nitrobenzene diazonium chloride. Reduction of the diazo intermediates gave 2- and 1-aminopyrroles (3 and 4). The 2-aminopyrrole (3) was determined to be the process impurity formed during a furan-pyrrole heteroatom exchange reaction. An oxidative mechanism for the impurity formation was hypothesized. Nitrogen sparging of the reaction mixture prior to heating eliminated formation of 3.