Chlorination of Pyrrole. N-Chloropyrrole: Formation and Rearrangement to 2- and 3-Chloropyrrole

Article abstract of DOI:10.1021/jo00345a023

N-Chloropyrrole (2) was formed in 65-72percent yield when pyrrole (1) in CCl4 was chlorinated with aqueous NaOCl.This intermediate rearranged in methanol to give chloropyrroles by two distinct reactions: a thermal rearrangement which gave 2-chloropyrrole (3) and an acid-catalyzed intermolecular reaction which gave 2-chloropyrrole (3), 3-chloropyrrole (4), and 2,5-dichloropyrrole (5).Nucleophilic attack on the N-Cl bond of 2 was demonstrated by reactions in the presence of CN^- and SCN^-.In the latter case, 2-(thiocyano)pyrrole was formed.