Aromatic structures sulphur-containing

Recent work ( ) with model organosulphur compounds has shown that at temperatures above 350 C and pressures in excess of 100 atm (1500 psig), the hydrolytic desulphurisation reaction occurs readily with thioethers, mercaptans and other non-thio-phenic types of organosulphur compounds. Thiophene itself is more resistant to this type of reaction but desulphurisation is significant in the 450 - 500 C range. More complex fused ring sulphur containing aromatic structures, can, however, be more reactive. 

The reaction of sulphides with (dichloroiodo)benzene can lead to several kinds of products depending on the substrate and the reaction conditions [19]. Sulphides of great structural diversity (aliphatic, aromatic, heterocyclic) were oxidized efficiently by (dichloroiodo)benzene (one equivalent) in aqueous pyridine. The reaction was almost instantaneous and not noticeably sensitive to steric or electronic effects. Ethylenic double bonds were not attacked under these conditions however, in vinylic sulphides containing an electron-withdrawing group (COOH or RSO) ft- to the sulphur atom the oxidation was accompanied by nucleophilic attack to the double bond resulting in a mixture of products. The method is suitable for the preparation of I80-labelled sulphoxides using small quantities of H2,80. 

The pale yellow colour of nitrobenzene or p- nitrotoluene turns more intense when the compound is dissolved in sulphuric acid, while solutions of nitromethane and other nitroparaffins are colourless. The yellow colour of the aromatic nitro compounds is due presumably to an ionic structure containing a quinonoid ring. 

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