Novel heterocyclic systems. Part 21. Synthesis of 3-hydroxypyridine-2(1H)-selone and its application in the synthesis of 1-azaphenoxaselenine and its substituted derivatives

3-Hydroxypyridine-2(1H)-selone (2) is produced by the reaction of sodium hydrogen selenide, prepared in situ, with 2-chloro-3-hydroxypyridine. Reaction of the dianion of selone (2) with 1-chloro-2-nitrobenzene produces a new heterocyclic system, 1-azaphenoxaselenine (1). The same procedure is also applied in the synthesis of a range of substituted 1-azaphenoxaselenines via reactions of the dianion of (2) with various substituted ortho-chloronitrobenzenes