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Vol. 23, S o . 1
A New Group of Anthraquinone Vat Colors Containing the -CONH- Linkage‘ Ralph N. Lulek E. I. DU POXT
Older Anthraquinone Vat Colors
DB
NEMOURS & COXPANY, WILXINGTOX,DEL
It is well known that benzoylation of amino anthraquinones lightens the color of the resulting products and increases their tinctorial value, as shown in the series of the simple Algol colors. If the newly developed anthronecarboxylic acid chloride derivatives are used for substitution of aminoanthraquinones and derivatives therefrom, the following changes in the shade and properties of the resulting products are induced: (1) The anthraisothiazol-2-carbonylgroup lightens the shade, similarly to the benzoyl group, but also greatly increases the tinctorial value. (2) The anthraisoselenazol-2-carbonylgroup produces about the same tinctorial value as the anthraisothiazol-2-carbonyl group, but deepens the shade of the products. (3) The anthraisothiophene-2-carbonylgroup deepens thecolor more than the anthraisothiazol-2-carbonyl group, but decreases the tinctorial value. (4) In all the above-mentioned acid-chloride-substituted aminoanthraquinones, chlorine in the 6-position effects greater tinctorial value than alpha chlorine. (5) -0”-in the beta position of the anthrone molecule produces greater tinctorial value and enhances the depth of the shades more than -CONH- in either 4 or 5 position.
T IS desirable to review briefly the older types of a n t h r a q u i n o n e vat c o l o r s c o n t a i n i n g +e -CONH- linkage before discussing the new type described in this paper. The benzoylaminoanthraquinones are the most important substituted aminoa n t h r a q u i n o n e s . A large number of vat colors have been discovered in this field and several of these occupy important positions among the vat colors on the market today. The aminoanthraquinones, used for benzoylation, usually contain the amino group or g r o u p s in the a l p h a p o s i t i o n . The shade of the mono- and d i - a m i n o anthraquinones is red. According to the terminology in 0. N. mitt’s theory on color and constitution, benzoylation effects a “lightening” of the shade and increases the affinity for fiber. For example, a-aminoanthraquinone is a red compound of practically no tinctorial value. Alpha-benzoylaminoanthraquinone,
I
“-CO(-)
v-co-v formerly on the market as Algol Yellow WG, dyes cotton in yellow shades. Thus, the red color of a-aminoanthraquinone in very fine suspension or dry form is changed, by benzoylation, from red to yellow and the product is changed from one possessing negligible tinctorial value to a dyestuff of good affinity. The shade of the product depends upon the number and the positions of the benzoylamino groups. 1,5-dibenzoyldiaminoanthraquinone is a dyestuff of a yellow shade and is still in the trade, 1,fbDibenzoyldiaminoanthraquinone is very similar t o the 1,5 derivative but is inferior in fastness properties. NH.CO
0
I n the 1,4 positions we observe a change in shade from yellow to red, the 1,4-dibenzoyldiaminoanthraquinone being a red vat color. Three benzoylamino groups in one anthraquinone molecule “deepen” the shade still further towards the blue. The l14,5-tribenzoyltriaminoanthraquinone is B o r d e a u x red. Other substituents introduced into the aminoanthraquinone molecule also change the shade. For e x a m p l e , halogen has a tendency to l i g h t e n the shade. 1-Benzoylamino-6-c h 1or o a n t hraq u i n o n e , 1- henzoylamino-4chloroanthraquinone, and 1-b e n z o y 1 a m i n o -5-c hlor oanthraquinone are g r e e n e r than a-benzoylaminoanthraquinone itself. Hydroxy groups, on the other hand, “deepen” the shade. The a-monohydroxy and a-dihydroxy derivatives of lJ5-dibenzoy1diaminoanthraquinone are red and violet, respectively. Acid chlorides other than benzoyl chloride have been condensed with aminoanthraquinones-i. e., carbonyl chlorides of naphthalene, anthraquinone, and their derivatives. Hereafter, in this paper, the acid chloride part of the dyestuff molecule will be called the acid substitutent and the acid substituent together with the entire -CONH- linkage will be considered an auxochrome. Various results may be obtained by increasing the molecular weight of the acid substituent. Naphthoylaminoanthraquinones are very similar to the benzoylamino derivatives. Anthraquinone-0-carboxylic acid chloride is not superior to benzoyl chloride when used as acid substituent. 1-Chloroanthraquinone-2-carboxylic acid has been the subject of investigation in this field and patents have been issued on its use (6). The dyes obtained have weak tinctorial value and range from orange to weak red. The chlorine in the alpha position of the acid molecule may be substituted by an amino group either by amidation under pressure or by means of p-toluenesulfonamide. The amino group deepens the shade of the products but does not improve the affinity for fiber. The object of this investigation was to find acid chlorides which would increase the affinity of the condensation products obtained and produce new shades. Condensation Products of AnthraquinonecarboxylicAcids
(_)-CO.NH 1 Received October 11, 1930. Presented before the Division of Dye Chemistry at the 80th Meeting of the American Chemical Society, Cincinnati, Ohio, September 8 to 12, 1930.
Anthraquinonecarboxylic acids were used as acid substituents because of the stability of their chlorides, the size of the molecule, and the various possibilities for substitution and
IAYDVSTRIALdAVDESGINEERISG CHE.lfISTRE7
January, 1931
ring forination in the molecule. In all cases five membered rings nere formed, leading from the 1 to the 9 position with loss of the oxygen atom in the ketonic group. lI9-dnthraisothiazol-2-carboxylicacid was by far the most valuable of the acids prepared. The ring formation takes place very easily by heating 1-chloroanthraquinone-2-carboxylic acid with polysulfide and ammonia according to known methods. The stable acid chloride of the 1,9anthrathiazol-2-carboxylic acid thus formed is easily prepared by means of either thionyl chloride or phoqphorus pentachloride (3). 71
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derivatives. This sulistitution of one benzoyl group by an anthrathiazol group effects an increase in the affinity for the fiber as well as a change in shade from the reddish yellow of the 1,5-dibenzoyldiaminoanthraquinoneto the greenish yellow of the monoanthrathioxopl derivative. S----S
A- cI 1 -/\-coyii
Sl a
When one of the benzoyl groups in the 1.4-dibenzoyldiaminoanthraquinone is replaced by an anthraisothiazoyl group, the shade is changed from red to orange-hrown. A- ---3
Condensations were carried out between this new acid chloride and practically all the known aminoanthraquinones as well as a large number of aromatic and aliphatic amines i5). The description here will be restricted to a few condensation products with typical amines which yielded the best results. The condensation product of 1,9-anthraisothiazoI-Z-carbony1 chloride with a-aminoanthraquinone is a greenish yellow dyestuff, lighter in shade than the corresponding benzoyl compound, and is much superior to it, as a vat color, in both fastness and affinity for the fiber. h7H%
S--S I1
T h e n both amino groups in a diaminoanthraquinone are condensed with anthraisothiazolcarboxylicacid chloride, dyestuffs are obtained tvhich are inferior, in strength and other properties, to the benzoylaminoanthrathiazoyl condensation products. I n this series of vat dyestuffs, therefore, it seems that a molecule which contains one anthraquinone and two anthrathiazol nuclei is too large to yield a vat color of good dyeing properties and tinctorial power. All the new r a t colors obtained by substituting the anthrathiazol nucleus for the benzoyl group in benzoylaminoanthraquinones are cold-dyeing colors. When applied to the fiber, therefore, they behave in much the same way as the analogous benzoylamino dyes. Other new carboxylic acid chlorides of l,9-anthrathiazol lJ9-anthrathiazol-4-carbonyl were also prepared-namely, chloride and 1,9-anthrathiazol-5-carbonylchloride. N--S 11
T a t dyes were obtained by condensing different chloroaminoanthraquinones with 1,9-anthraisothiazol-2-carbonyl chloride. I-Amino-4-chloro- and I-amino-5-chloroanthraquinone, each containing chlorine in the alpha position, yield dyestuffs which possess about the same affinity and fastness properties. 1-Amino-6-chloroanthraquinone yields an excellent vat color of very greenish yellow shade, which has three times the strength of the simple aminoanthraquinone condensation product. N--S II
I
N---S I
I
1
The intermediates used for this purpose were the l-chloroanthraquinone 4-and 5-carboxylic acids, respectively. These a-carboxylic acid chlorides, when condensed with the previous mentioned aminoanthraquinones, yield products which are very inferior to the @-carboxylic acid condensation products. The new a-carboxylic acid derivatives of other cyclic anthraquinones (which will be mentioned later) also yielded condensation products which were inferior to those prepared from the corresponding @-carboxylic acids. Anthraselenazol Carboxylic Acid Condensation Products
Xlonobenzoyldiaminoanthraquinoneswere also condensed with lJ9-anthraisothiazol-2-carbony1 chloride. The condensa&ion products obtained from monobenzoyl-1, 5-diaminoanthraquinone, and monobenzoyl-l,4-diaminoanthraquinone a r e both lighter than the corresponding dibenzoyldiamino
Analogous to the new isotliiazolanthrones or anthrathiazolcarboxylic acids are the new isoselenazolanthrone- or anthraselenazolcarboxylic acids, which contain selenium in the molecule in place of sulfur. Although isoselenazolanthrone is a known compound ( I ) , there is no record indicating that vat colors have been prepared which contain this structure.
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The vat colors prepared from 1,9-anthraisoselenazol-2carboxylic acid ( 5 ) possess excellent properties and are surpassed in this line only by the anthrathiazol condensation products. The method used for the preparation of isoselenazolanthrone-2-carboxylic acid was quite analogous to that used for the preparation of the thiazol derivative. It was found necessary, however, to isolate the anthraquinone-l-selenophenol-2-carboxylic acid, while the corresponding l-mercaptoanthraquinone-2-carboxylic acid was not isolated. The subsequent selenazol ring formation takes place in the presence of ammonia in the autoclave.
7'
Seh'a
torial power, therefore, of the anthrathiazol substituent was decreased as the result of replacing the nitrogen atom in the heterocyclic ring by a methine group. Comparison of Color and Constitution of New Products
As mentioned before, if a-aminoanthraquinone or its derivatives are benzoylated the shade of the product is lightened. This is due to the modification of the auxochrome, which in this case is the amino group. A new auxochrome is formednamely, the benzoylated amino group-which gives the compound its affinity for fiber and makes it a vat color. The new acid chlorides act in the same way, but their auxochromic character is much stronger than that of the benzoyl group and dyestuffs of much better tinctorial value are produced from them. A comparison between 1,9-anthrathiazol-2-carboxylic acid and the selenium analog shows that the selenium compound is much redder than the sulfur compound. A similar comparison may be drawn between the simple a-mercapto-anthraquinone and anthraquinone-a-selenephenol, the former being yellow and the latter orange. N--s
The anthraisoselenazol-Zcarboxylic acid is more deeply colored than the analogous sulfur compound. Also, when 1,9-anthraisoselenazol-2-carbonylchloride is condensed with aminoanthraquinone, vat colors are obtained which are much deeper in shade than the corresponding sulfur containing dyestuffs. For example, the condensation product prepared from this selenazol and 1-amino-6-chloroanthraquinone
Vol. 23, No. 1
N--Se
Yellow
Orange
N--Se
The peri-ring formation, therefore, does not preclude this difference in shade. With regard to the comparative auxochromic character of the thiazol and selenazol structures, it will be noted that the latter produces the stronger auxochrome since i t deepens the color of the condensation products. \i-CO-(J-Cl If we compare the yellow anthrathiophene acid with the greenish yellow anthrathiazol acid, it can be said that the is almost as red as anthrathiazoyl-benzoyl-1,5-diaminoanthraquinone, which, of course, is considerably redder than deeper color of the former is due to the C=C linkage in the l,9-anthrathiazoyl-l-amino-6-chloroanthraquinone. The thiophene ring, which is a much stronger chromophore than the C=N linkage in the thiazol ring. This deduction is properties of the dyestuffs obtained are excellent. further verified when the structures of pyranthrone and flavanthrone, in which these chromophores appear, are reAnthraisothiophene-2-Carboxylic Acid Condensation called. The strong auxochromic character of anthrathioProducts phene readily manifests itself in the condensation products If the nitrogen atom in the anthrathiazoyl is replaced with between 1,9-anthrathiophene-2-carbonyl chloride and aminoa methine group, one obtains a thiopheneanthrone (2). The anthraquinones. Although the color of the resulting dye1,9-thiopheneanthrone-2-carboxylic acid was obtained by stuffs is deepened, their tinctorial power is weakened. condensing 1-mercaptoanthraquinone-2-carboxylicacid with Another factor is the position of the carboxylic acid group chloroacetic acid in alkali. in the anthraquinone molecule. It seems essential to have A thioglycolic acid derivative is first formed, and the thio- the carboxylic acid group in the beta position of the anthrone phene ring is then closed as Cot and HZO split off. derivative in order to obtain condensation products which possess strong affinity for the fiber. Anthrathiazol, anthraselenazol, and anthrathiophene acid substituents containing the carboxylic acid group in the 4- or 5-position, respectively, have been prepared. I n every case the dyestuffs prepared from these alpha acids were inferior in both shade and strength to those prepared from the corresponding beta acids. C,H--S
The acid chloride of this acid, when condensed with aminoanthraquinones, yields weak dyeing dyestuffs. The tinc-
Literature Cited (1) Bayer, D. R. P. 264,139 (1912); Friedl, XI. 1129 (1912). (2) Gattermann, Ann., 393, 122 (1912). (3) Lulek, U. S. Patent 1,706,981(1929). (4) Lulek, U. S. Patent 1,705,023(1929). (5) Lulek, Patent applications pending. (6) Naviasky and Sauervein, U. S. P. 1,539,689(1925); Rollett, Monatsh., 46, 131 (1925).
