Reaction #155361

Reaction equation

anthra[2,3-b]benzo[d]thiophene

dibenzothiophene

aluminum chloride

phosphorus pentachloride

phthalic anhydride

→

anthra[2,3-b]benzo[d]thiophene-7,12-dione

Conditions

Workup

1. 1
   Otherto give 2-(2′-carboxybenzoyl)dibenzothiaphene

Procedure

The synthesis of the anthra[2,3-b]benzo[d]thiophene unit with added trialkylsilylethynyl groups is shown in Scheme 1. Commercially available dibenzothiophene undertakes a Friedel-Crafts reaction with phthalic anhydride to give 2-(2′-carboxybenzoyl)dibenzothiaphene. The acid is then treated with aluminum chloride and phosphorus pentachloride to yield anthra[2,3-b]benzo[d]thiophene-7,12-dione. The dione is alkylated with the lithium salt of the trialkylsilylacetylene reagent followed by aromatisation utilising tin (II) chloride under acidic conditions to give 7,12-bis(trialkylsilylethynyl)anthra[2,3-b]benzo[d]thiophene.

Source