4-Chlorophenol → Quinizarin

Participants

Reaction Steps

The present invention relates to a process for the production of 1,4,5,8-tetrahydroxyanthraquinone (hereinafter referred to as diquinizarine) by reacting phthalic anhydride with p-chlorophenol in oleum and in the presence of boron catalysts to give the boron complex of 1,4-dihydroxyanthraquinone, and then chlorinating this boron complex direct with chlorinating agents, in the same reaction medium, to give the boron complex of 5,8-dichloro-1,4-dihydroxyanthraquinone, and subsequently hydrolysing this chlorinated boron complex to diquinizarine.

Provenance & Evidence