Chapter 29 - Six-membered Heterocycles Containing Phosphorus, Arsenic, Antimony and Bismuth as a Single Heteroatom

Abstract

This chapter focuses on the phosphorus, arsenic, antimony and bismuth compounds. A large number of organo-arsenic, -antimony and -bismuth compounds contain a single heteroatom in a six-membered ring system. Phosphorin is the alternative trivial name of the phosphorus analogue of pyridine. The phosphorus analogues of piperidine are malodorous liquids which react slowly with air and with elemental sulfur to give the corresponding phosphine oxides and phosphine sulfides. Phosphorinane arises from the reaction of monosodium phosphine and 1,5-dibromopentane. A large number of arsenane derivatives are prepared by using similar techniques and bear close chemical similarities to the phosphorinanes. The key compound of arsenin has been prepared from 1,4-dihydro-1,1-dibutylstannabenzene and arsenic trichloride. It is a colorless liquid. It is isolated by preparative gas-liquid chromatography and degrades rapidly in air. Antimonanes are converted in a similar manner to the phosphorus and arsenic analogues by the reaction of a pentane-l, 5-dimagnesium halide and a dichlorostibene. The only known compounds of antimony in a condensed ring system are the 5-substituted-5,10-dihydrodibenz antimonins. The only example of a six-membered heterocycle consisting of bismuth is the pyrophoric 1-ethyibisminane. It is derived by an analogous route to that used for the antimonins.