H. Lee, B. Palmer, M. Boyd
Jul 1, 1996
Citations
0
Influential Citations
5
Citations
Journal
Journal of Heterocyclic Chemistry
Abstract
While reaction of 2-bromo-5-nitrothiazole (2) with weakly basic secondary aliphatic amines gives the expected 2-amino products from nucleophilic displacement of the bromine, reaction of the isomeric 5-bromo-2-nitrothiazole (3) with such amines gives mixtures of the expected 5-amino products together with 2-aminated 5-nitrothiazole rearrangement products. The identity of the latter were detemined by alternative synthesis, and by X-ray crystallographic determination of a derivative. The mechanism proposed is a slow thermal isomerization of 5-bromo-2-nitrothiazole (3) to the much more reactive 2-bromo-5-nitro isomer 2 which competes, in the case of relatively weak amine nucleophiles, with the direct (but slow) nucleophilic displacement of the 5-bromo group to form the normal displacement products.