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Fast Halogenation of Some N ‐ Heterocycles by Means of N , N′ ‐Dihalo‐5,5‐dimethylhydantoin
Author(s) -
Sandtorv Alexander H.,
Bjørsvik HansRené
Publication year - 2013
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201200723
Subject(s) - halogenation , chemistry , bromine , chlorine , reagent , catalysis , iodine , organic chemistry , reaction conditions , combinatorial chemistry , medicinal chemistry
An instantaneous, selective and high‐yielding halogenation process is reported. The method operates with imidazoles, pyrazoles, and indoles under benign reaction conditions. The developed process involves the use of N,N′ ‐dihalo‐5,5‐dimethylhydantoins (halo=chlorine, bromine, iodine) as halogenation reagents that are activated by catalytic quantities of a strong Brønsted acid. Moreover, the halogenation process is switchable to produce either the mono‐ or di‐halogenated products. Issues related to the reaction mechanism are investigated and a proposal for a reaction mechanism is disclosed.