Production of 1-amino-4-hydroxyanthraquinones substituted in the 2- and/or 3-positions
United States Patent 1191 Hiller et al.  
 [451 Apr. 29, 1975 1 PRODUCTION OF l-AMINO-4-I-IYDROXYANTIIRAQUINONES SUBSTITUTED IN THE 2 AND/OR 3-POSITIONS [76] Inventors: Heinrich Hiller, Corneliusstrasse,  
 6800 Mannheim; Alfred Schuhmacher, 36 von-weber-Strasse; Helmut Goerth, 15 Rubensstrasse, both of 6700 Ludwigshafen, all of Germany 22 Filed: Dec. 15, 1974 21 Appl. No.: 315,473  
 [52] US. Cl 260/380; 260/376 [51] Int. Cl. C09b 1/50 [58] Field of Search 260/377, 376, 380  
 [56] References Cited UNITED STATES PATENTS 1,798,156 3/1931 Gubelmann et a1. 260/380 1,867,069 7/1932 Gassncr et al. 260/380 FOREIGN PATENTS OR APPLICATIONS 301.119 11/1928 United Kingdom 260/380 OTHER PUBLICATIONS Bamett, Anthracene and Anthroquinone, pp. 130-132 (1921) QD393B3.  
 Beilstein, Handrich der Organischen Chemie, 4th Ed. Band 14, p. 268, (1931).  
 Primary Examiner-Lorraine A. Weinberger Assistant ExaminerE. .lane Skelly Attorney, Agent, or Firm-Johnston, Keil, Thompson &amp; Shurtleff [57] ABSTRACT Production of 1-amino-4-hydroxyanthraquinones, which can be substituted in the 2- and 3-positions by carboxylic acid, carboxylic ester or alkyl groups or chlorine or bromine, by heating 3&#39;-nitrobenzoylbenzoic acids, which can be substituted in the 4- and 5&#39;-positions, in sulfuric acid or oleum in the presence of boric acid, boric acid esters, boron trihalides or their complex compounds to temperatures between about 120 and 200C. The reaction products are dyes or intermediates for valuable disperse dyes.  
 8 Claims, No Drawings PRODUCTION OF 1-AMINO-4-HYDROXYANTHRAQUINONES SUBSTITUTED IN THE 2- AND/ OR S-POSITIONS The invention relates to a process for the production of l-amino-4-hydroxyanthraquinones which can be substituted in the 2- and 3-positions.  
  l-amino-4-hydroxyanthraquinones substituted in the 2- and 3-positions by halogen, alkyl, carboxyl or alkoxycarbonyl are dyes or serve as intermediates for the production of dyes. For example, 1-amino-2-ch1oro-4- hydroxyanthraquinone or its 2-bromo counterpart is an important intermediate for the production of valuable disperse dyes.  
  l-amino-2-bromo-4-hydroxyanthraquinone is obtained, for example, by bromination of 1- aminoanthraquinone to 2 ,4-dibromol aminoanthraquinone and subsequent hydroxylation of the dibromo compound in sulfuric acid/boric acid. The corresponding 2-chloro compound of 1-amino-4- hydroxyanthraquinone can, for example, be obtained according to U.S. Pat. No. 1,798,156 from 3&#39;-amino- 4,6&#39;-dichlorobenzoyl-benzoic acid by ring closure in concentrated sulfuric acid and subsequent hydroxylation of the resulting dichloro-anthraquinone derivative in concentrated sulfuric acid/boric acid, but is only obtained in moderate yields. Both processes are expensive in terms of equipment and therefore not economic. Moreover, with the first process there is the disadvantage that about 50 percent of the bromine used is lost, so that the costs are still further increased.  
  The object of the present invention was to find an economic and technically simple process for the production of l-amino-4-hydroxyanthraquinones which can be substituted in the 2- and 3-positions.  
  [t has surprisingly been found that 1-amino-4- hydroxyanthraquinones of formula 1 Reduction in which X and Y have the above meanings, are heated in to weight percent sulfuric acid or in oleum containing up to 15 weight percent of free sulfur trioxide in the presence of boric acid, boric esters, boron trihalides or their complexes to about to 200C. The reaction mixture obtained is then worked up in known manner.  
  The result of the process of the invention is surprising because it is known that 3&#39;-nitro-4-ch1orobenzoy1- benzoic acid cannot be converted into the corresponding anthraquinone derivative by treatment with sulfuric acid or oleum. The ring closure to the anthraquinone derivative proceeds only after reduction of the 3 &#39;-nitrobenzoyl-benzoic acid to the corresponding amino compound. In this case, after the ring closure a mixture of 1-amino-2-chloro-and 2-amino-3-chloroanthraquinone is obtained in a ratio of 30:60 weight percent:  
 o NH2 Weight Sulfuric acid It was not to be expected that, for example, 3&#39;-nitro- 4&#39;-chlorobenzoyl-benzoic acid would be converted into l-amino-2-chloro-4-hydroxyanthraquinone by heating in sulfuric acid in the presence of boric acid or boron trihalides.  
  As alkoxycarbonyl groups for X and Y there may be mentioned, for example, methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, n-butoxycarbonyl, ibutoxycarbonyl, n-amyloxycarbonyl, i-  
 amyloxycarbonyl, n-hexoxycarbonyl and i-hexoxycar- 1O its alkali metal salts, elemental sulfur in the form of a powder, and iron in the form of a powder or turnings. An optimum yield of the reaction product is obtained when at least 4 redox equivalents of reducing agents 5 are introduced for each nitro group. In this case conversions of up to 80 percent, based on the theoretically possible conversion, are-achieved.  
  The amount of reducing agent depends, amongst other things, not only on the 3-nitrobenzoyl-benzoic acid but also on the type and the condition of the reducing agent itself. In general, however, an amount of 4 to 7 redox equivalents per nitro group is sufficient. However, larger amounts of reducing agent can also be introduced without impairing the reaction.  
  Besides boric acid itself, salts of boric acid such as sodium borate, esters such as the trimethyl ortriethyl ester, or boron trihalides such as boron trichloride, boron tribromide or boron trifluoride, or their complexes such as boron trifluoride hydrate, boron trifluoride etherate or the complexes of boron trifluoride with phosphoric acid, can be used. However, the use of boron The process of the invention is generally carried out by introducing the 3 &#39;-nitrobenzoyl-benzoic acid derivative of formula 11 into the mixture of boric acid and sulfuric acid or boric acid and oleum, and heating the resulting mixture to 120 to 200C, preferably l40 to 170C. Depending on the temperature and the nitrobenzoyl-benzoic acid introduced, the reaction is complete after 2 to 10 hours.  
  The reaction can also be carried out at temperatures above 200C but products are then obtained which are not sufficiently pure for use as dyes or as intermediates for the production of dyes, and which must therefore be purified before use.  
  Particularly high yields of anthraquinone compounds of formula I are obtained with short reaction times when the reaction in the boric acid/sulfuric acid or boric acid/oleum mixture is carried out in the presence of reducing agents. Suitable reducing agents are, for example, sodium sulfite, potassium sulfite, sodium hydrogen sulfite, hydroxymethanesulfinic acid, the alkali metal salts of thiosulfuric acid, sodium dithionite, the salts of oxalic acid, the salts of formic acid, glucose, paraformaldehyde, iron(ll) sulfate, sulfur or metals such as zinc, iron, aluminum, magnesium, nickel or copper, or even catalytically active hydrogen. When carrying out the process on a commercial scale the reducing agents that are preferred above all are paraformaldehyde, hydroxymethanesulfinic acid in the form of 40 trihalides confers no advantage over the use of boric acid.  
  The reaction of the 3&#39;-nitrobenzoyl-benzoic acid of the formula II is therefore preferably carried out in the presence of at least 4 redox equivalents of a reducing agent at temperatures between about 140 and 170C. Under these conditions an optimum yield of the reduction product is obtained in a short time with a content of to weight percent or more of the desired anthraquinone derivative of formula I. The products obtained in this way are in most cases sufficiently pure for processing into dyes or other intermediates so that they can be used without purification. If for any reason a purer product is required the content of anthraquinone derivative (I) can be easily increased to to 96 weight percent by suitable purification treatments such as sublimation or recrystallization or by redissolving in sulfuric acid and allowing crystallization to occur. These purified products satisfy practically all requirements to be met by starting materials for the synthesis of dyes or dye intermediates.  
  Because 3&#39;-nitrobenzoyl-benzoic acids of formula ll are, as a rule, produced by nitration of the corresponding benzoyl-benzoic acids in sulfuric acid, a particularly advantageous and therefore preferred variant of the process of the invention consists in producing the 3&#39;-nitrobenzoyl-benzoic acid by nitration in sulfuric acid and introducing the nitration mixture containing nitric acid and sulfuric acid. Boric acid or one of the other boron compounds mentioned is added to the nitration mixture obtained, and the water contained in the nitration mixture is converted into sulfuric acid by v the addition of oleum. After the addition of the reducing agent the mixture is heated to 120 to 200C and, 1  
 after the reaction has ended, is worked up in the usual &#39;manner.  
  This advantageous variant is particularly preferred for the production of 1-amino-4- hydroxyanthraquinone derivatives of formula lb:  
 in which X is chlorine, bromine, methyl, tert.-butyl or sec.-amyl. Benzoyl-benzoic acids of formula 11 in which Y is hydrogen are preferred in this case.  
  The reaction mixture obtained upon completion of the reaction is worked up in conventional manner, for example the reaction mixture cooled to 50 to 100C is introduced into water or ice/water and the precipitated until neutral, suitably with warm water, and if desired dried.  
  The products of the process are in some cases dyes which dye synthetic fibers. for example fibers of linear polyesters, of polyamides or of cellulose acetate, brilliant red shades. Above all, however, the products serve as intermediates for the production of valuable disperse dyes.  
 The following Examples will further illustrate the invention. The parts and percentages mentioned are by weight.  
 EXAMPLE 1 l-amin0-2-chloro-4-hydroxyanthraquinone 15 parts of boric acid and 31 parts of 3&#39;-nitro-4&#39;- 5O chlorobenzoyl-benzoic acid are added to 300 parts of 5 percent oleum. The mixture is heated in 1 hour to 170C and held at this temperature for 2 hours. Thereafter it is allowed to cool to about 100C and poured into 1200 parts of water, and the precipitated product is boiled for a short time. After filtration, washing until neutral and drying, 25 parts of a red powder with a purity of 45 percent, i.e., a yield of 40 percent of the calculated yield, is obtained.  
 EXAMPLE 2 153 parts of 3-nitro-4&#39;-chlorobenzoyl-benzoic acid, parts of boric acid and 20 parts of paraformaldehyde are added successively to 1800 parts of 5 percent oleum. The mixture is heated in 1 hour to 160C 65 and held at this temperature for 3 hours. It is allowed to cool to C and poured into 6000 parts of water, and the precipitated product is boiled for a short time.  
 After filtration, washing and drying, parts of a crude product with a purity of 55 percent, i.e., a yield of 48 percent of the calculated yield, is obtained.  
 EXAMPLE 3 310 parts of 3&#39;-nitro-4-ch1orobenzoyl-benzoic acid is dissolved in 4000 parts of 4 percent oleum and 35 parts of powdered sulfur is added. After stirring for 1 hour 160 parts of boric acid is added and the mixture is heated to C. This temperature is maintained for 5 hours. After cooling to 100C the product is precipitated by pouring into 16000 parts of water, stirred for 1 hour at 90C and filtered off whilst hot. After washing until neutral and drying, 240 parts of l-amino-4- hydroxy-2-chloroanthraquinone with a purity of 78 percent is obtained.  
 EXAMPLE 4 20 310 parts of 3&#39;nitro-4-chlorobenzoyl-benzoic acid is dissolved in 4000 parts of 4 percent oleum. After the addition of parts of boric acid and 150 parts of iron powder the mixture is heated within 2 hours to 160C and held at this temperature for a further 3 hours with vigorous stirring. After working up as described in Example 3 parts of l-amino-4-hydroxy-2- chloroanthraquinone with a purity of 80 percent is obtained.  
 EXAMPLE 5 260 parts of 4-chlorobenzoyl-benzoic acid is dissolved in 1600 parts of 96 percent sulfuric acid and nitrated at a temperature of about 35by dripping in 122 parts of a nitrating acid consisting of 52 percent nitric acid (100 percent) and 48 percent sulfuric acid (100, percent).  
  Thereafter 160 parts of boric acid, 2400 parts of 24 percent oleum and 150 parts of iron powder are added and the mixture is heated in 2 hours to 160C. The mixture is held at this temperature for a further 3 hours with vigorous stirring and thereafter worked up as described in Example 3. 260 parts of 1-amino-4-hydroxy- 2-chloroanthraquinone with a purity of 80 percent is obtained, i.e., a yield of 73.5 percent of the theory, calculated on the chlorobenzoyl-benzoic acid charged.  
 EXAMPLE 6 70 parts of 4-tert.-butylbenzoyl-benzoic acid are dissolved in 300 parts of 96 percent sulfuric acid and nitrated with 31 parts of the nitrating acid described in Example 5 at 35C. After the addition of 40 parts of boric acid, 700 parts of 24 percent oleum and 35 parts of iron powder the mixture is heated in 2 hours to 155C and afterward stirred for a further 3 hours at this temperature. After cooling to 120C the reaction mixture is poured into 4000 parts of water. The mixture is then worked up as described in Example 3. 58 parts of crude 1-amino-4-hydroxy-2-tert.-butylanthraquinone, which dyes polyester fibers in red shades, is obtained.  
 EXAMPLE 7 The procedure described in Example 6 is repeated except that in place of 4-tert.-butylbenzoyl-benzoic acid 73 parts of 4&#39;-sec.-amylbenzoyl-benzoic acid is used. 60 parts of crude 1-amino-4-hydroxy-2-sec.-  
 amylanthraquinone, which dyes polyester fabrics in red shades, is obtained.  
  7 EXAMPLE 8 31.5 parts of 3&#39;-nitro-4-carboxybenzoyl-benzoic acid, 15 parts of boric acid and 15 parts of iron powder are heated in 300 parts of 5 percent oleum to l60C in 8 EXAMPLE 21 153 parts of 3&#39;-nitro-4&#39;-chlorobenzoyl-benzoic acid, 90 parts of boric acid and 70 parts of the sodium salt of hydroxymethanesulfinic acid are stirred into 2000 1 hour. The mixture is afterward stirred for 2 hours at 5 Parts O 5 percent oleum and the mixture is heated to this temperature, then allowed to cool to 100C and I50o t 5 h urs. After Working up as depoured into 1200 parts of water. After filtration, washscribed in Example 135 Parts Of Product With a P ing until neutral and drying, 26 parts of crude l-aminoy 0f 78 P ce Of l-amin0-2-chloro-4- 4-hydroxyanthraquinone 2-carboxylic acid is obtained y y q is obtainedand can be used without further purification to dye acewe Claim: tate rayon brilliant red ViOiet and nylon 6 blue-violet. 1 A process for the production of a l-amin0 4 EXAMPLE 9 hydroxyanthraquinone of the formula 35 parts of 3&#39;-nitro-4&#39;-bromobenzoyl-benzoic acid, 0 NH parts of boric acid and 4 parts of powdered sulfur 2 are heated in 300 parts of5 percent oleum to 150C for X 5 hours. Thereafter the reaction mixture is allowed to l 1 cool and poured into 1200 parts of water. After stirring -&amp; \K Y for a short time it is filtered, washed until neutral and 0 OH dried. 28 parts of l-amino-4-hydroxy-2- bromoanthraquinone with a purity of 80 percent is obi whi h tamed X is chlorine, bromine or hydroxy and Y is hydrogen,  
  chlorine or bromine, EXAMPLE 10 wherein a 3-nitrobenzoyl-benzoic acid of the formula 28.7 parts of 3&#39;-nitro-4&#39;-hydroxybenzoyl-benzoic acid, 15 parts of boric acid and 4 parts of powdered sul- 0 N0 fur are heated in 300 parts of 5 percent oleum to 150C L X for 6 hours. The product is worked up according to Exm ample 9. 24 parts of l-amino-2,4-dihydroxyanthraqui- C Y none with a purity of percent is obtained. EXAMPLES 11-18 153 parts of 3&#39;-nitro-4&#39;-chlorobenzoyl-benzoic acid, in which X and Y having the meanings defined above, parts of boric acid and 20 parts of sulfur are succes- 35 is heated in 90 to weight percent sulfuric acid or sively added to 1800 parts of 5 percent oleum. The in oleum with up to 15 weight percent of free sulfur trimixture is reacted under the conditions given in the foloxide in the presence of boric acid, a boric ester, a lowing Table. The reaction mixture is worked up as deboron trihalide or a boron trihalide complex to to scribed in Example 2: 200C.  
 EXAMPLE ll l2 l3 l4 l5 l6 l7 l8 Temperature (C) 120 M0 160 170 I80 I90 200 Reaction time (hours) 20 20 IO 4 3 2 2 2 Yield (parts) 100 HO l20 125 120 H0 H0 H0 Purity of l-amino-2- chloro-4-hydroxyanthraquinone (71) 30 63 7O 68 65 6O 55 50 EXAMPLE l9 2. A process according to claim 1 wherein a 3&#39;- 153 parts of 3, nitro 4, chlorobenzoyl benzoic acid 50 nitrobenzoylbenzoic acid in which Y 18 hydrogen is EXAMPLE 20 153 parts of 3&#39;-nitro-4&#39;-chlorobenzoyl-benzoic acid and parts of trimethyl borate are added to 1500 parts of 5 percent oleum. The mixture is slowly heated to l55 to C and stirred at this temperature for 7 hours. After working up as described in Example 19, 90 parts of a crude product with a purity of 45 percent of l-amino-2-chloro-4-hydroxyanthraquinone is obtained. v  
 used.  
  3. A process according to claim 1 wherein the reaction is carried out in the presence of a reducing agent.  
  4. A process according to claim 3 wherein iron, sulfur, parformaldehyde or an alkali metal salt of hydroxymethanesulfinic acid is used as reducing agent. 5. A process according to claim 3 wherein at least 4 redox equivalents of reducing agent are used for each nitro group.  
  6. A process according to claim 5 wherein 4 to 7 redox equivalents of reducing agent are used for each nitro group.  
  7. A process according to claim 1 wherein the reaction is carried out at 140 to C.  
  8. A process according to claim 1 wherein the 3&#39;- nitrobenzoylbenzoic acid is produced by nitration in sulfuric acid and is introduced into the reaction in the form of the nitration mixture.  
 UNITED STATES PATENT AND TRADEMARK OFFICE CERIFIQATE OF COBECTIQN PATENT NO. 3,880,892.  
 DATED 1 April 29, 1975 INVENTOR(S) HILLER et a1 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below: 0  
 In the Heading, delete [22] Filed; December 15, 1974&#34; and insert-{22] Filed; December 15, 1972-- d In the Heading, insert--[30] Foreign Application Priority Data December 18, 1971 Germany P 21 63 059.1-- &#39;2 In Column 6, Line 26, Delete &#34;165&#34; and insert--265- Signed and geaicd this eleventh Day Of May 1976 [SEAL] Arrest:  
 : RUTH-C. MASON c. MARSHALL DANN Arresting ()f/lcer of &#34;1mm and Trademark