Preparation of 5-halo-2-(1-anthraquinonylamino)-benzoic acids and 4'-halo-2,1(N)-anthraquinonyl-1',2'(N)-benzacridones
AssigneeBASF SE
InventorsMichael Schmitt, Matthias Niedenbrueck, Manfred Patsch
Life of this patent
Estimating the term…
Abstract
There are described the preparation of 5-halo-2-(1-anthraquinonylamino)benzoic acids of the general formula I ##STR1## (X.sup.1 : Cl or Br; X.sup.2 : H, Cl or Br, identical or different when n>1; n: 1-6) by reacting 2-(1-anthraquinonylamino)benzoic acids II ##STR2## with the halogen in the presence of sulfuric acid, and the preparation of 4'-halo-2,1(N)-anthraquinonyl-1',2'(N)-benzacridones III ##STR3## by cyclizing condensation of the acids I.
Claims8
A process for preparing 5-bromo-2-(1-anthraquinonylamino)benzoic acids of the formula I ##STR11## where X.sup.1 is bromine,
- X.sup.2 is hydrogen, chlorine or bromine, the X.sup.2 radicals for n>1 being identical or different, and n is from 1 to 6,
- which comprises adding 1-1.5 molar equivalents of bromine to a reaction medium consisting essentially of 2-(1-anthraquinonylamino)benzoic acid of formula II ##STR12## and 96 to 100 wt. % sulfuric acid at a temperature of 0.degree.-25.degree. C.
A process for preparing 4'-bromo-2,1(N)-anthraquinonyl-1,2'(N)-benzacridones of the formula III ##STR13## where X.sup.1 is bromine,
- X.sup.2 is hydrogen, chlorine or bromine, the X.sup.2 radicals for n>1 being identical or different, and n is from 1 to 6,
- which comprises first adding 1-1.5 molar equivalents of bromine to a reaction medium consisting essentially of 2-(1-anthraquinonylamino)-benzoic acid of formula II ##STR14## and 96 to 100% sulfuric acid at a temperature of 0.degree.-25.degree. C. to form a 5-bromo-2-(1-anthraquinonylamino)benzoic acid of the formula I ##STR15## in at least 92% absolute yield and then removing excess bromine and product hydrogen bromide and then raising the temperature to 50.degree.-100.degree. C.
Dependencies are inferred from the claim text.