Process for preparing triphendioxazine compounds

A novel, simple process for preparing triphendioxazines by oxidative cyclization of 2,5-diarylaminobenzoquinones in sulphuric acid which, if necessary, contains sulphur trioxide consists in using as an oxidizing agent chlorine, bromine or an inorganic bromine compound.

The present invention relates to a novel process for preparing 
triphendioxazine compounds by oxidative cyclization of 
2,5-diarylaminobenzoquinones in sulphuric acid or sulphuric acid 
containing sulphur trioxide, characterized in that the oxidizing agent 
used is chlorine, bromine or an inorganic bromine compound. 
Inorganic bromine compounds which may be mentioned are for example: sodium 
and potassium bromide, sodium and potassium bromate and also hydrobromic 
acid. 
In this process, about 0.5 to 10, preferably 0.5 to 3 moles of chlorine, 
bromine or inorganic bromine compounds are used per mole of 
2,5-diarylaminobenzoquinone. 
The cyclization is in general carried out at 0.degree. to 60.degree. C., 
preferably at 10.degree. to 30.degree. C. 
The reaction medium employed is preferably concentrated sulphuric acid, 
monohydrate or fuming, containing up to 50% of sulphur trioxide. The 
choice of the suitable reaction medium depends mainly on the 
diarylaminobenzoquinone and the cyclization agent. In the case of 
2,5-diarylaminobenzoquinones which can be sulphated relatively easily, 
concentrated sulphuric acid up to about 5% strength fuming sulphuric acid 
is preferred. In other cases, due to the short reaction times which can be 
obtained by this method, 10 to 50% strength fuming sulphuric acid, very 
particularly 10 to 30% strength fuming sulphuric acid is preferred. 
Examples of 2,5-diarylaminobenzoquinone compounds which can be used 
according to the invention as starting compounds and which may be 
mentioned are compounds of the general formula 
##STR1## 
in which T.sup.1, T.sup.2 are independently of each other H, Cl, Br, 
C.sub.1 -C.sub.4 -alkoxy, C.sub.1 -C.sub.4 -alkyl, optionally substituted 
phenyl or phenoxy radicals, 
R.sup.1, R.sup.2 are independently of each other optionally substituted 
phenyl, naphthyl, carbazolyl, fluorenyl, chrysenyl or pyrenyl radicals. 
Suitable substituents for the optionally substituted phenyl or phenoxy 
radicals T.sup.1 and T.sup.2 are for example Cl, CH.sub.3, C.sub.2 
H.sub.5, OCH.sub.3, OC.sub.2 H.sub.5 and NO.sub.2. 
Suitable substituents for R.sup.1 and R.sup.2 are for example as follows: 
Alkyl, such as methyl, ethyl, n-propyl, n-butyl, cyclohexyl, alkoxy, such 
as methoxy, ethoxy, isopropoxy, cyclohexyloxy, fluorine, chlorine, 
bromine, carboxyl, sulpho, sulphamoyl, acylamino, such as acetylamino, 
propionylamino, ureido, benzoylamino, amino, alkylamino such as 
methylamino, ethylamino, .beta.-aminoethylamino, .gamma.-aminopropylamino, 
.gamma.-dimethylaminopropylamino, aryloxy, such as phenoxy, arylamino such 
as anilino, benzylamino, cyclohexylamino, arylthio, phenyl, benzyl, 
phenylureido, .beta.-hydroxyethylsulphonyl, .beta.-hydroxyethylamino, 
.gamma.-hydroxypropylamino, .beta.-sulphatoethylamino, 
.gamma.-sulphatopropylamino, bis-.beta.-sulphatoethylamino, 
bis-.beta.-sulphoethylamino, .beta.-hydroxyethoxy, .beta.-hydroxypropoxy, 
.beta.-hydroxyethylthio, .gamma.-hydroxypropylthio, .beta.-sulphoethoxy, 
.beta.-sulphatoethoxy, .beta.-(.beta.'-hydroxyethoxy)ethoxy, 
(.beta.-hydroxyethyl)amino, .beta.-hydroxypropylamino, 
.beta.-sulphoethylamino, .gamma.-sulphopropylamino, 
.beta.-(4-sulphophenyl)-ethylamino, 
.beta.-(2,4-disulphophenyl)-ethylamino, .beta.-(2-sulpho-4-.beta.-hydroxye 
thylsulphonyl)ethylamino, bis-(.beta.-hydroxyethyl)amino, 
N-methyl-N-(.beta.-hydroxyethyl)amino, 
N-ethyl-N-(.beta.-hydroxyethyl)amino, N-methyl-(.beta.-sulphoethyl)amino 
or N-ethyl-N-(.beta.-sulphoethyl)amino. 
The alkyl, benzyl and phenyl radicals mentioned here can themselves be 
further substituted, for example by NH.sub.2, NHCH.sub.3, OCH.sub.3, 
OC.sub.2 H.sub.5, SO.sub.3 H, COOH, NHCOCH.sub.3, Cl, Br, NHSONH.sub.2, 
OH, SCH.sub.3, SO.sub.2 NH.sub.2, CONH.sup.2+ N(CH.sub.3).sub.3, SO.sub.2 
CH.sub.2 CH.sub.2 OSO.sub.3 H. From the abundance of radicals R.sup.1 and 
R.sup.2 which are possible the following may be mentioned as examples: 
4-Amino-3-sulphophenyl, 
3-Amino-4-sulphophenyl, 
4-(4'-Amino-3'-sulphoanilino)-3-sulphophenyl, 
4-(3'-Amino-4'-sulphoanilino)-3-sulphophenyl, 
4-(2'-Aminoethylamino)-3-sulphophenyl, 
4-(3'-Aminopropylamino)-3-sulphophenyl, 
4-(4'-Aminocyclohexylamino)-3-sulphophenyl, 
4-Ethylamino-3-sulphophenyl, 
4-.beta.-Hydroxyethylamino-3-sulphophenyl, 
4-.beta.-Methoxyethylamino-3-sulphophenyl, 
6-Amino-1,5-disulpho-3-naphthyl, 
4-Benzylamino-3-sulphophenyl, 
4-Phenoxy-3-sulphophenyl, 
4-(.beta.-Aminoethylamino)-3-(.beta.-sulphoethylsulphamoyl)phenyl, 
4-(.beta.-Sulphoethylamino)-3-(.beta.-aminoethylsulphamoyl)phenyl, 
4-Ethoxy-3-(.beta.-hydroxyethylsulphonyl)phenyl, 
4-Methoxy-3-(.beta.-sulphatoethylsulphonyl)phenyl, 
4-(.beta.-Hydroxyethylamino)-3-(.beta.-hydroxyethylsulphonyl)phenyl. 
The preparation of the 2,5-diarylaminobenzoquinones from arylamines and 
1,4-benzoquinones is carried out by methods, such as are described for 
example in K. Venkataraman "The Chemistry of Synthetic Dyes" volume V, p. 
419-427 (1971) and in Ullmanns Encyclopadie der technischen Chemie 
[Ullmann's Encyclopaedia of Industrial Chemistry], 4th edition, volume 8, 
p. 240 and 241 (1974) and also in German Offenlegungsschrift No. 
2,823,828. 
Thus, the 2,5-diarylaminobenzoquinones of the formula (I) where T.sup.1 
=T.sup.2 =Cl are for example prepared from 2,3,5,6-tetrachlorobenzoquinone 
and arylamine in water at 30.degree.-50.degree. C., the pH being 
maintained at 5 to 6 by means of a basic compound, for example sodium 
carbonate. Compounds of the formula (I) where T.sup.1 =T.sup.2 =H can be 
prepared from 2,5-dihydroxybenzoquinone and an aromatic amine in glacial 
acetic acid at 20.degree. to 100.degree. C. 
2,5-Diarylaminobenzoquinones having .beta.-hydroxyethylsulphonyl or 
.beta.-hydroxyethylamino radicals are sulphated before or during the 
cyclization. 
The work-up of the reaction products obtained in the cyclization reaction 
is carried out by methods known per se. 
The process according to the invention makes it possible to carry out 
cyclization under very mild conditions. It is in particular also possible 
to cyclize in high yields compounds I where T.sup.1 =T.sup.2 =H which by 
the known methods (oxidizing agents: sulphur trioxide, alkali metal peroxy 
disulphate, sodium borate, iodine or an inorganic iodine compound) cannot 
be cyclized or are difficult to cyclize. Simultaneously with the 
cyclization, halogenation is carried out under the reaction conditions to 
give 6,13-dichloro- or dibromo-triphendioxazines (T.sup.1 =T.sup.2 =Cl, 
Br). 
By further halogenation, in particular in the presence of catalysts (for 
example I.sub.2), more highly halogenated triphendioxazines can be 
obtained. 
The triphendioxazines which can be obtained according to the invention are 
known. 
The triphendioxazines which contain sulpho groups can be used for dyeing 
wool or synthetic polyamides, while those which additionally contain amino 
groups can be used, after acylation, for example with di- or 
trihalotriazines or di-, tri- or tetrahalopyrimidines, for dyeing cotton.

EXAMPLE 1 
58.5 parts of a condensation product prepared according to DE-A No. 
3,439,756 from 48 g of 2,3,5,6-tetrachlorobenzoquinone and 102 g of 
4-.beta.-hydroxyethylamino-3.beta.-hydroxyethylsulphonylaniline in water 
at a pH of 5-6 are added at 20.degree. C. to 250 parts of 20% strength 
fuming sulphuric acid. Stirring is continued for one hour at 20.degree. to 
25.degree. C., 19 parts of bromine are rapidly added to the mixture, which 
is stirred for 2 hours at 20.degree. to 25.degree. C. with slight cooling. 
The melt is then poured onto 800 g of ice, and the product is precipitated 
by adding 200 g of potassium chloride. The precipitate is filtered with 
suction, washed with 25% strength potassium chloride solution, and the 
filter cake is dried in vacuo at 60.degree. C. The salt-containing product 
contains &lt;0.1% of organic bromine and 5.4% of organic chlorine and 
essentially corresponds to the formula 
##STR2## 
It dyes cotton in a deep blue colour having a slight red tinge. 
EXAMPLE 2 
(a) 50.4 parts of 2,5-dihydroxybenzoquinone and 209 parts of 87% strength 
4-.beta.-hydroxyethylamino-3-.beta.-hydroxyethylsulphonylaniline are added 
at 70.degree. C. in succession to 1 l of glacial acetic acid. The mixture 
is stirred for 3 hours at 70.degree. C., cooled to 20.degree.-25.degree. 
C., filtered with suction, and the product is dried in vacuo at 50.degree. 
C. The product essentially corresponds to the formula 
##STR3## 
(b) 56 parts of the intermediate product prepared according to (a) are 
added to 250 parts of 20% strength fuming sulphuric acid. The melt is 
stirred at 25.degree. C. for 1 hour. 30 parts of brom-ine-are then added 
in 2 portions and the mixture is stirred at 25.degree. C. for 5 hours. The 
melt is poured onto 800 parts of ice to which a small amount of sodium 
hydrogen sulphite solution has been added. The product is salted out by 
adding 250 g of potassium chloride, is filtered off with suction, washed 
with 20% strength potassium chloride solution and dried. The 
salt-containing product contains 9.0% of organic bromine and essentially 
corresponds to the formula 
##STR4## 
It dyes cotton in deep blue shades having a slight red tinge. 
EXAMPLE 3 
56 parts of the condensation product prepared according to Example (2a) are 
added to 300 parts of 20% strength fuming sulphuric acid, and the mixture 
is stirred at 15.degree. to 20.degree. C. for 2 hours. Chlorine is then 
passed in at 15.degree. to 20.degree. C. until, normally after 3 to 4 
hours, a worked-up sample indicates complete cyclization to the 
triphendioxazine compound. The ready-prepared melt is poured onto 1,000 
parts of ice, the product is salted out by adding 200 parts of potassium 
chloride, filtered off with suction, washed with 20% strength potassium 
chloride solution and dried in vacuo at 60.degree. C. The product is 
essentially identical with the dye prepared according to Example 1. 
EXAMPLE 4 
If the procedure of Example 3 is repeated with the exception that before 
the chlorination 0.3 g of iodine is added, a more highly halogenated 
triphendioxazine of the following formula is obtained 
##STR5## 
EXAMPLE 5 
45 parts of a product mixture obtained according to DE-A No. 3,530,830, 
Example 1, by condensation of 19 parts of 1,4-diaminobenzene-2-sulphonic 
acid and 26 parts of 
3-.beta.-hydroxyethylsulphonyl-4-.beta.-hydroxyethylaminoaniline with 26 
parts of 2,3,5,6-tetrachlorobenzoquinone are added at 20.degree. C. to 250 
parts of 10% strength fuming sulphuric acid. Stirring is continued for 2 
hours, 28 g of bromineare then rapidly added, and the mixture is stirred 
for 2 hours with slight cooling. After pouring onto ice, the mixture is 
brought to a pH of about 1.5 using calcium carbonate, and then to a pH of 
5.5 using sodium carbonate. Calcium sulphate is filtered off with suction, 
and the filtrate is concentrated by evaporation. The salt-containing 
product mixture thus isolated contains the triphendioxazine of the 
following formula 
##STR6## 
as the main component. 
It dyes cotton in a deep blue colour.