Kinetics and mechanism of bromination of 2-pyridinone and related derivatives in aqueous solution was written by Tee, Oswald S.;Paventi, Martino. And the article was included in Journal of the American Chemical Society in 1982.Electric Literature of C5H3Br2NO This article mentions the following:
The tautomeric system 2-pyridone (I) ⇄ 2-hydroxypyridine (II) reacts with aqueous Br via the principal tautomer I at pH <6 and via the conjugate anion at pH >6. Attack upon I occurs preferentially at the 3 position, whereas reaction of the anion probably involves major attack at the 5 position. The facile dibromination of I results from the comparable reactivity of the monobromopyridones at pH <1 or pH >4. These conclusions are based upon kinetic and product studies of I bromination and various derivatives in aqueous solutions at pH 0-8. With respect to their reactivity toward Br, the pyridones behave as substituted phenoxide ions. In the experiment, the researchers used many compounds, for example, 3,5-Dibromo-2-hydroxypyridine (cas: 13472-81-6Electric Literature of C5H3Br2NO).
3,5-Dibromo-2-hydroxypyridine (cas: 13472-81-6) belongs to pyridine derivatives. Pyridine has a conjugated system of six π electrons that are delocalized over the ring. The molecule is planar and, thus, follows the Hückel criteria for aromatic systems. One of the examples of pyridines is the well-known alkaloid lithoprimidine, which is an A3 adenosine receptor antagonist and N,N-dimethylaminopyridine (DMAP) analog, commonly used in organic synthesis.Electric Literature of C5H3Br2NO