Bohn-Schmidt reaction

For the sake of completeness, the so-called Bohn-Schmidt reaction should ako be mentioned. This reaction is an oxidation of anthra-quinone with fuming sulfuric acid or, under some circumstances, the oxidation of the nitro derivative in the presence of sulfur and boric acid. At the present time, these reactions are of little importance technically. 

Protection of OH groups. The Bohn-Schmidt reaction, discovered independently in rival German dye firms (Badische Company, Friedrich Bayer), consists in hydroxylation of an anthraquinone with fuming sulfuric acid and boric acid, often in the presence of a catalytic amount of mercury. Boric acid appears to be beneficial... 

Bohn-Schmidt reaction, 64-65 Boiling stones, 62-63 Bombykol, 735 Borane, 1230... 

Bohn-Schmidt reaction. Hydroxylation of anthraquinones containing at least one hydroxyl group by fuming sulfuric acid or sulfuric acid and boric acid in the presence of a catalyst such as mercury. 

This reaction was first reported by Bohn in 1889 and subsequently by Schmidt in 1891. It is the introduction of hydroxyl groups into anthraquinone molecules containing at least one hydroxyl group by the oxidizing action of fuming sulfuric acid (i.e., oleum). Therefore, it is generally known as the Bohn-Schmidt reaction. It is reported that if boric acid is added to the reaction mixture, then ordinary concentrated sulfuric acid can be used instead of the oleum, and boric acid can form esters with hydroxyanthraquinones to prevent the further oxidation. In addition, selenium, selenium oxide, and mercury can be added as catalytic agents. ... 

Other references related to the Bohn-Schmidt reaction are cited in the literature. 

Bodroux-Chichibabin Aldehyde Synthesis Bogert-Cook Synthesis Bohn-Schmidt Reaction... 

In 1901, Rend Bohn, head of the BASF alizarin laboratory, applied the indigo reaction conditions to 2-aminoanthraquinone (46) and discovered a blue colorant that he named indanthrone, from indigo and anthraquinone . He then obtained the same product more directly from 46. Later known as indanthrene blue RS (47), it was the first of the anthraquinone vat dyes, more correctly anthraquinonoid vat dyes, also known as indanthrene dyes (Scheme 18). With this innovation, three types of anthraquinone dyes became available mordant (such as alizarin), acid (Robert E. Schmidt, at Bayer, 1894) and vat. 

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