Large-scale solvent-free chlorination of hydroxy-pyrimidines, -pyridines, -pyrazines and -amides using equimolar POCl3 was written by Wang, Han;Wen, Kun;Wang, Le;Xiang, Ye;Xu, Xiaocheng;Shen, Yongjia;Sun, Zhihua. And the article was included in Molecules in 2012.Quality Control of 3,5-Dibromo-2-hydroxypyridine This article mentions the following:
Chlorination with equimolar POCl3 can be efficiently achieved not only for hydroxypyrimidines, but also for many other substrates such as 2-hydroxypyridines, -quinoxalines, or even -amides. The procedure is solvent-free and involves heating in a sealed reactor at high temperatures using one equivalent of pyridine as base. It is suitable for large scale (multigram) batch preparations In the experiment, the researchers used many compounds, for example, 3,5-Dibromo-2-hydroxypyridine (cas: 13472-81-6Quality Control of 3,5-Dibromo-2-hydroxypyridine).
3,5-Dibromo-2-hydroxypyridine (cas: 13472-81-6) belongs to pyridine derivatives. Pyridine’s the lone pair does not contribute to the aromatic system but importantly influences the chemical properties of pyridine, as it easily supports bond formation via an electrophilic attack. Many analogues of pyridine are known where N is replaced by other heteroatoms . Substitution of one C閳ユ弻 in pyridine with a second N gives rise to the diazine heterocycles (C4H4N2), with the names pyridazine, pyrimidine, and pyrazine.Quality Control of 3,5-Dibromo-2-hydroxypyridine