Chapter 49 - Compounds with Six-Membered Heterocyclic Rings containing One or More Unusual Hetero Atoms together with Nitrogen or Elements of Group VI

Abstract

The replacement of two adjacent carbon atoms in an aromatic hydrocarbon ring system by a unit consisting of adjacent boron and nitrogen atoms provides a heterocyclic system, which is isoconjugate with the parent hydrocarbon, and the expectations that such heterocyclic compounds should then display a chemical character similar to that of the parent hydrocarbon have been realized to a considerable extent. The conjugated boron-nitrogen compounds show remarkably high chemical stability, the majority being resistant to acids, bases and oxidizing agents. This complex group consists of oxa- and thia-borins, dioxaborins, dioxadiborins, trioxadiborinanes, azalumines and azaborines, diazaluminines and diazaborines, triazaborines, azadiborines, diazadialuminines and diazadiborines, and their benzologues, and triazadiborines. Silicon, germanium, tin and lead compounds include oxa-silins, -germanins and -stannins, and their thia analogues, dioxasilins, dioxagermanins, dioxastannins and their thia analogues, trioxasilacyclohexanes, trithiastannacyclohexanes, dioxadisilins, dioxagermasilins and dioxadigermalins, oxa- and dioxa-trisilacyclohexanes, azasilines, diazasilines,diazastannines, triazasilines, azadisilines, diazadisilines and analogues. Phosphorus, arsenic and antimony compounds consist of oxaphosphorins, oxarsenins and their thia-analogues, dioxaphosphorins, dioxarsenins, dioxantimonins and their thia analogues, perhydro-oxadiphosphorins (oxadiphosphorinanes), dioxadiphosphorinanes and arsenic analogues, azaphosphorines and their arsenic analogues, diazaphosphorines, triazaphosphorines, perhydro tetra-aza-phosphorines and-arsenines, diaza- and triaza-diphosphorines, diazatriphosphorines, and diazatriarsenines.