查看文章

This chapter deals with condensed ring systems of 1,2,4-triazines with six and seven-membered heterocycles, and condensed ring systems with triazine in the center. The chapter considers the order of increasing number of heteroatoms in the fused ring and each is followed in turn by a heterocycle fused to a benzene ring. Each fused ring system is arrangedaccording to the order of fusion on the triazine ring. Specifically, the chapter describes pyrido[1 ,2,4]triazines, pyrano[ 1 ,2,4]triazines, diazino[1,2,4]triazines, [ 1 ,2,4]triazino-oxazines, [ 1 ,2,4]triazino-thiazines, triazino[ 1 ,2,4]triazines, triazino-oxadiazine, triazino-thiadiazine, triazino-dioxazines, and heterocyclo-triazino heterocycles. With regard to pyrido[l,2,4]triazines, it is observed that there are eight theoretically possible pyridotriazines. Four of them possess bridgehead nitrogen with faces b, c, d, and f common to the triazine ring. The other …