Dibenzothiophene dioxide derivs prodn - 3-nitro-and 3,7-dinitro-dibenzothiophen-5,5- dioxide prodn by oxidn of dibenzothiopene in substd (cyclo) alkane and direct nitration

摘要

Prodn. of 3-nitro- and 3,7-dinitro-dibenzothiophen-5,5-dioxide (I) comprises dissolving dibenzothiophene (II) in (cyclo)aliphatic hydrocarbons (III) with one or more halogen (F, Cl, Br), NO2 or alkylsulphonyl substits., oxidising with H2O2 in the presence of a strong acid (IV) and nitrating the resultant dibenzothiophen-5,5-dioxide (V), without isolation, with a nitrating agent (VI), opt. with addn. of water-binding agent (VII). (I) are valuable intermediates for the prodn. of dyes, esp. azo dyes. The process is simple and gives good yields.