New anthraquinone dyes, free of water-solubilizing groups such as --SO.sub.3 H and --CO.sub.2 H comprise anthraquinone substituted with one or more identical or different groups of the formula --NHSO.sub.2 R, wherein R is a substituted or unsubstituted linear, branched, cyclic or polycyclic alkyl group having up to 20 carbon atoms, and wherein the remaining nuclear aromatic carbon atoms of the anthraquinone may be substituted with substituents selected from the group: alkyl; the halogens F, Cl, and Br; cyano; nitro; aminosulfonyl; arylsulfonylamino; and --NHCOQ; wherein Q is hydrogen, an alkyl, an aryl, or a heterocyclic group. These dyes have improved solubility, lowered melting point, and possess outstanding resistance to light-induced fading.

CROSS-REFERENCE TO RELATED CASES 
Some of the dyes included in the claims of the present case are included in 
examples of eutectic combinations of dyes for thermal imaging in 3M patent 
application Ser. No. 193,947 filed on May 13, 1988. 
BACKGROUND TO THE INVENTION 
1. Field of Invention 
This invention relates to coloring materials and, more particularly, to 
dyes of the anthraquinone class having alkylsulfonylamino substituents. 
In the practice of the present invention, the term "sulfonylamino" is used 
to identify that the substituent is uniquely bonded to the ring through 
the nitrogen atom, i.e., RSO.sub.2 NH--. Although chemical nomenclature is 
clear on the point, the term "sulfonamido" is used in the literature to 
mean a substituent bonded either through the nitrogen (correct) or through 
the sulfur atom (incorrect) thus creating confusion. Similarly we have 
used the term "carbonylamino" to clarify the position with the carboxylic 
acid equivalents bonded through the nitrogen atom. 
2. BACKGROUND OF THE ART 
While many yellow, orange and red anthraquinone dyes are available, for 
example acylamino-substituted anthraquinones, there remains a need for 
improving properties other than purely optical and color considerations 
such as hue. The successful application of dyes to a variety of processes 
requires tailoring of properties other than color to the needs of the 
application. For example, for outdoor signs good weathering resistance of 
the dyes used is a prerequisite. In the production of colored coatings on 
objects, solubility of the dye in the coating medium is a key 
characteristic. For dyes incorporated in liquid crystal devices, a high 
order parameter is desirable. In thermal dye transfer imaging applications 
control of dye melting point is crucial to effective image formation. In 
fluorescent inks, the emission wavelength of the dye in relation to its 
absorption wavelength is an important criterion. 
Anthraquinone dyes with acylamino substituents, free of auxochromic groups 
such as amino, alkoxy and alkylthio, are well known in the art. Acylamino 
groups of the alkylcarbonylamino and arylcarbonylamino variety are known, 
the latter in particular being common (e.g., CI 60520, CI 61650, CI 
61725). 
Anthraquinones substituted solely with arylsulfonylamino groups have also 
been reported. These are described, for instance, in: F. Ullmann, Ber., 
43, 536 (1910); H. Kauffmann and H. Burckhardt, Ber., 46, 3808 (1913); F. 
Ullmann and G. Billig, Ann., 381, 11 (1911); R. Scholl et al., Ber., 62, 
107 (1929); K. Naiki, J. Soc. Org. Synth. Chem. Japan, 13, 72 (1955); and 
in German Pat. No. 224,982 and U.S. Pat. Nos. 3,274,173 and 3,240,551. 
These are, in general, high melting, poorly soluble, rather intractable 
materials. 
Anthraquinones have also been described in which arylsulfonylamino and 
arylcarbonylamino groups are simultaneously present. Such materials may be 
found in the aforementioned U.S. Pat. No. 3,240,551, in U.S. Pat. Nos. 
1,939,218 and 1,966,125, and in German Pat. Nos. 623,069 and 647,406. 
In view of the fact that anthraquinones substituted with alkylcarbonylamino 
groups have been known for over 100 years (see e.g., H. Roemer, Ber., 15, 
1786 (1882)), it is surprising that the first simple 
alkylsulfonylaminoanthraquinone was reported only in 1986 in Japanese 
Kokai JP61-10549. That patent application claims, among other materials, 
anthraquinones bearing a single lower alkyl- or lower 
haloalkylsulfonylamino substituent, with an additional substituent in each 
outer ring selected from hydrogen, lower alkyl, lower haloalkyl or 
halogen. They are described as useful for their anti-inflammatory, 
antipyretic, analgesic and diurectic activity. These materials are stated 
to be prepared by reaction of an aminoanthraquinone with an alkanesulfonyl 
chloride in the presence of pyridine, as is known in the art. All the 
concrete examples of this patent involve either the methylsulfonylamino or 
the trifluoromethylsulfonylamino substituent. We have been able to prepare 
these same derivatives in good yield by the stated method. However, in 
work on the present invention, all attempts to prepare alkylsulfonylamino 
derivatives containing two or more carbon atoms by said method were, 
surprisingly, unsuccessful. This observation may be related to the 
intervention of sulfene intermediates in these types of reaction. (See, 
for example J. F. King, Acc. Chem. Res., 8, 10 (1975)). Whatever the 
cause, we have been able to prepare mono- and poly-alkylsulfonylamino 
derivatives with two or more carbon atoms only by other methods described 
in detail below, thus providing the first access to this class of 
materials. Additional art pertinent to these materials is U.S. Pat. No. 
4,062,875, which describes a process comprising treating a 
2-acylamino-2'-carboxydiphenylmethane with an acid condensing agent, 
whereby there is formed the corresponding 4-acylaminoanthrone, which may 
be oxidized to the corresponding anthraquinone. The patent does not, 
however, disclose any example of the process operated with an acyl radical 
derived from a sulfonic acid. U.S. Pat. No. 3,558,698 concerning 
N-substituted perfluoroalkanesulfonamides claims anthraquinonyl 
derivatives, among others. The example of 
2-trifluoromethylsulfonylaminoanthraquinone is provided. This material is 
not a dye. In U.S. Pat. No. 3,278,549 there are disclosed water-soluble 
reactive dyes, exhibiting good wash fastness on cellulose and protein 
fibers, characterized by the presence of a 1,2,2-trifluorocyclobutyl 
group, optionally containing additional substituents. This group may be 
attached to a variety of dyes, including anthraquinone dyestuffs, by a 
range of amide links among which are --NHSO.sub.2 -- and --NHSO.sub.2 
CH.sub.2 CH.sub.2 -- linkages. All the examples of anthraquinone dyes 
contain at least two --SO.sub.3 H groups, and contain the 1-amino and 
4-anilino auxochromic groups. In the single instance of a --NHSO.sub.2 -- 
link this group is not attached to the anthraquinone nucleus, and the dye 
is blue. 
U.S. Pat. No. 3,617,173 claims polyester fibers dyed with 
2-aroylanthraquinones having various amino substituents in the 1- and 
4-positions. The possibility of simultaneously included 
1-arylsulfonylamino and 4-alkylsulfonylamino substituents appears to be 
considered, but no examples are provided of such materials. This is not 
surprising in view of the steric hindrance towards introduction of large 
1-substituents presented by the 2-aroyl group. Indeed, all the samples in 
this patent contain either a simple amino or a methylamino group in the 
1-position, reflecting the difficulty of synthesis of the above materials. 
Although thermal printing of textiles bears a superficial resemblance to 
diffusive thermal dye imaging, in reality quite different processes with 
distinct properties and material requirements are involved. Thermal 
printing occurs by a sublimation process, so that substantial vapor 
pressure is a prime criterion for dye selection. In diffusive dye imaging, 
high vapor pressure of the dye contributes to undesirable thermal fugacity 
of the image. For the melt state diffusion process involved in this 
situation, melting point is instead a better basis for dye selection. 
Diffusive dye transfer is a high resolution dry imaging process in which 
dye from a uniform donor sheet is transferred in an imagewise fashion by 
differential heating to a very smooth receptor, using heated areas 
typically of 0.0001 square inches or less. In contrast, the thermal 
printing of textiles is of comparatively low resolution, involving 
contemporaneous transfer by uniform heating of dye from a patterned, 
shaped or masked donor sheet over areas of tens of square feet. The 
typical receptors printed in this manner are woven or knitted fabrics and 
carpets. The distinct transfer mechanism allows such rough substrates to 
be used, while diffusive imaging, where receptors with a mean surface 
roughness of less than 10 microns are used, is unsuitable for these 
materials. Unlike diffusive thermal dye imaging, the transfer printing 
process is not always a dry process; some fabrics or dyes require 
pre-swelling of the receptor with a solvent or a steam post-treatment for 
dye fixation. Though the transfer temperatures for the two processes can 
be similar (180.degree. to 220.degree. C.), diffusive dye transfer 
generally operates at somewhat higher temperatures. However, in a manner 
strikingly reflective of the differences in mechanism involved, diffusive 
dye transfer involves times of around 5 msec, whereas thermal printing 
normally requires times of 15 to 60 sec. In accord with the sublimation 
process involved, thermal printing often benefits from reduced atmospheric 
pressure or from flow of heated gas through the donor sheet. Thermal 
printing is a technology developed for coloring of textiles and is used to 
apply uniformly colored areas of a predetermined pattern to rough 
substrates. In contradistinction, diffusive dye transfer is a technology 
intended for high quality imaging, typically from electronic sources. 
Here, a broad color gamut is built with multiple images from donors of the 
three primary colors onto a smooth receptor. The different transfer 
mechanism allows the requirement for grey scale capability to be 
fulfilled, since the amount of dye transferred is proportional to the heat 
energy applied. In thermal printing grey scale capability is expressly 
shunned, because sensitivity of transfer to temperature decreases process 
latitude and dyeing reproducibility. 
When auxochromic groups such as alkylthio, alkoxy, amino and substituted 
amino are introduced into the anthraquinone nucleus along with alkyl- or 
arylsulfonylamino groups, the resulting dyes are generally red, violet, or 
blue. Many examples of these dyes are known in the art. Typically, both 
aryl- and alkylsulfonylamino derivatives are claimed in the same patent, 
without any differentiation in properties. Examples of such materials are 
contained in U.S. Pat. Nos. 2,640,059, 3,394,133, and 3,894,060, wherein a 
single sulfonylamino substituent is present, and in U.S. Pat. No. 
3,209,016 and Japanese Kokai 63-258955, wherein two sulfonylamino groups 
may be present. In other instances, alkyl- and 
arylsulfonylaminoanthraquinones of otherwise identical structure are 
claimed in separate patents, again with no distinction between the 
properties of the two classes. Thus, U.S. Pat. No. 1,948,183 claims 
1-amino-2-alkoxy-4-arylsulfonylaminoanthraquinones, while U.S. Pat. No. 
3,072,683 claims 1-amino-2-alkoxy-4-alkylsulfonylaminoanthraquinones. 
As was stated previously, arylsulfonylaminoanthraquinones without 
auxochromic groups are rather intractable materials. In contrast, the new 
yellow, orange and red alkylsulfonylaminoanthraquinones of this invention 
are more valuable dyes by virtue of their increased solubility in 
non-aqueous solvents and reduced melting points, which render them more 
useful for a variety of applications. Despite the absence of the arylamide 
groups usually associated with good fading resistance, these dyes provide 
excellent photostability. 
SUMMARY OF THE INVENTION 
New yellow, orange, and red dyes of the anthraquinone class with improved 
solubility in non-aqueous solvents and reduced melting points are 
described. 
These dyes have excellent fade resistance and unusual fluorescence 
properties. 
The anthraquinone dyes of the present invention may be represented in one 
sense by the general formula 
##STR1## 
wherein R is an alkylsulfonylamino group 
EQU --NHSO.sub.2 R' 
wherein where R' is an alkyl group other than methyl and halogenated methyl 
and all other substituents on the central nucleus are not auxochromic 
groups as defined herein. When or if there are more than two R groups, R' 
may be methyl. 
The anthraquinone dyes in another sense of the present invention may be in 
part described as free of water-solubilizing groups, and have the general 
structure: 
##STR2## 
wherein R.sup.1 to R.sup.8 are chosen independently from the group 
hydrogen, alkyl, F, Cl, Br, cyano, nitro, aminosulfonyl, 
arylsulfonylamino, --NHCOR.sup.9 group, and --NHSO.sub.2 R group, 
providing that at least one of R.sup.1 to R.sup.8 is an --NHSO.sub.2 R 
group, and wherein groups R are selected independently from linear, 
branched, cyclic or polycyclic alkyl groups having from 1 to 20 carbon 
atoms, said groups R, for example, being unsubstituted or independently 
substituted with up to 6 groups R.sup.10 selected independently from aryl, 
substituted aryl, heteroaryl, substituted heteroaryl, F, Cl, Br, alkoxy, 
aryloxy, alkylthio, arylthio, substituted amino, carbonyl (i.e., keto, 
aldehyde, oxycarbonyl group), carbonylamino, sulfonyl, sulfonylamino and 
cyano; and wherein R.sup.9 is hydrogen, or is selected from alkyl group, 
aryl group, or a heterocyclic group, optionally substituted with up to 6 
groups selected from said R.sup.10, provided that when only one of R.sup.1 
to R.sup.8 is --NHSO.sub.2 R and additionally R has a carbon atom alpha to 
the sulfonyl group capable of taking one or more substituents R.sup.11, 
then R.sup.11 is selected independently from hydrogen, aryl, substituted 
aryl, heteroaryl, substituted heteroaryl, alkoxy, aryloxy, alkylthio, 
arylthio, substituted amino, carbonyl, carbonylamino, sulfonyl, 
sulfonylamino and cyano. 
The compounds of this invention provide dyes of improved solubility in 
non-aqueous solvents and lowered, controllable, melting point, which 
possess outstanding resistance to light-induced fading. Some of the 
compounds also exhibit fluorescence characterized by an exceptionally 
large Stokes shift. 
The compounds of this invention are useful as colorants and in 
image-forming. They are particularly useful as dyes for thermal image 
transfer either separately or in combination with other dyes. 
DETAILED DESCRIPTION OF THE INVENTION 
There are a number of alternative ways of defining the dyes of the present 
invention so that they exclude all dyes of the prior art. The dyes may be 
defined in one sense as dyes having a central nucleus of the formulae 
##STR3## 
wherein R.sup.1 is an alkyl group comprising two or more carbon atoms, and 
does not have a halogen substituent on the carbon alpha to the sulfur 
atom; R.sup.2 -R.sup.4 may be any group other than auxochromic groups. 
Auxochromic groups are undesirable in cases where yellow, orange, or red 
dyes are desired. The term auxochromic as used herein is defined as RS--, 
RO--, and R.sub.2 N-- groups where R may be an alkyl or aryl group, or 
hydrogen. The central nucleus is preferably free of any other auxochromic 
groups other than additional alkylsulfonylamino groups, arylsulfonylamino 
groups, alkylcarbonylamino groups, and arylcarbonylamino groups. 
The dyes may also be described in a more general sense as dyes having a 
central nucleus of the formula 
##STR4## 
wherein R is an alkylsulfonylamino group 
EQU --NHSO.sub.2 R' 
wherein where R' is an alkyl group other than methyl and halogenated methyl 
and all other substituents on the central nucleus are not auxochromic 
groups as defined herein. When or if there are more than two R groups, R' 
may be methyl. 
The novel dyes of this invention are free from water-solubilizing groups 
such as --SO.sub.3 H and --CO.sub.2 H, and their central structure 
comprises anthraquinone, the nuclear aromatic carbon atoms of which are 
substituted with x groups of the formula --NHSO.sub.2 R, x being an 
integer in the range 1 to 8, inclusive, wherein R is a linear, branched, 
cyclic, or polycyclic alkyl group having from y to 20 carbon atoms, 
inclusive, said groups R being unsubstituted or substituted with up to 6 
groups R.sup.10 selected from aryl and substituted aryl, heteroaryl and 
substituted heteroaryl, the halogens F, Cl, and Br, alkoxy, aryloxy, 
alkylthio, arylthio, substituted amino, carbonyl, carbonylamino, sulfonyl, 
sulfonylamino and cyano, and wherein the remaining nuclear aromatic carbon 
atoms of the anthraquinone are additionally substituted with z identical 
or different substituents from the group alkyl, F, Cl, Br, cyano, nitro, 
aminosulfonyl, arylsulfonylamino, and --NHCOR.sup.9, but excluding certain 
oxy, thio, and amino linked substituents, namely the substituents 
--OR.sup.9, --SR.sup.9, --NHR.sup.9, --NR.sup.9, wherein R.sup.9 is 
selected from hydrogen; and alkyl, aryl, and heterocyclic group which may 
be substituted with up to 6 groups R.sup.10 ; and z is in the range 0 to 
8-x, and y is 1, with the proviso that, when x is 1, y is 2 and R is not 
halogen-substituted alpha to the sulfonyl group. 
Alkylsulfonylamino groups may be placed in the alpha or beta positions of 
the anthraquinone. The preferred position is alpha; thus 1-substituted, 
1,4-bissubstituted, 1,5-bissubstituted, 1,8-bissubstituted, 
1,4,5-trissubstituted and 1,4,5,8-tetrakissubstituted 
alkylsulfonylamino-anthraquinones are preferred. Of these, the 1-, 
1,4-bis-, 1,8-bis- and 1,4,5-tris(alkylsulfonylamino) derivatives are 
particularly preferred. 
The alkyl groups in the alkylsulfonylamino moiety may contain from 1 to 20 
carbon atoms, or from 2 to 20 carbon atoms in the case of 
mono-substitution. Preferably there are at least 3 carbon atoms. A most 
preferred range is from 6 to 16 carbon atoms. A great variety of alkyl and 
substituted alkyl groups may beneficially be used. Among alkyl groups 
there may be mentioned such groups as ethyl, and the isomers of propyl, 
butyl, amyl, hexyl, heptyl, octyl, decyl, lauryl, myristyl, palmityl and 
stearyl. Among cyclic alkyl groups there may be mentioned cyclobutyl, 
cyclopentyl, cyclohexyl, and cycloheptyl. Cyclohexyl is particularly 
preferred. Mention may also be made of other groups such as hydrindanyl, 
decalinyl, or alkyl groups derived from bicyclic systems, such as 
bicyclo[2.2.1]heptane and its alkylated derivatives, and 
bicyclo[2.2.2]octane and adamantane. In this case, it is preferred that 
there be an alkylene bridge between the cyclic system and the sulfonyl 
group. Of the various alkyl groups, linear and branched alkyl groups are 
especially preferred. A wide variety of substituent groups may be 
additionally present in the alkyl moiety of the alkylsulfonylamino group. 
In the case of mono-(alkylsulfonylamino)anthraquinones it is preferred, 
however, that the alkyl group be free of electron withdrawing groups alpha 
to the sulfonyl group such as halogen, nitro, sulfonyl, carbonyl and 
cyano, since these reduce the absorption of the material in the visible 
region of the electromagnetic spectrum. Suitable representative groups 
include: aryl and substituted aryl, heteroaryl and substituted heteroaryl, 
the halogens F, Cl, and Br, alkoxy, aryloxy, alkylthio, arylthio, 
substituted amino, carbonyl, carbonylamino, sulfonyl, sulfonylamino and 
cyano. 
It is well understood in this technical area, that a large degree of 
substitution is not only tolerated, but is often advisable. As a means of 
simplifying the discussion and recitation of these groups, the terms 
"group" and "moiety" are use to differentiate between chemical species 
that allow for substitution or which may be substituted. For example, the 
phrase "alkyl group" is intended to include not only pure hydrocarbon 
alkyl chains such as methyl, ethyl, pentyl, cyclohexyl, isooctyl, 
tert-butyl and the like, but also such alkyl chains bearing conventional 
substituents in the art such as hydroxyl, alkoxy, phenyl, halo (F, Cl, 
Br), cyano, nitro, amino, etc. The phrase "alkyl moiety", on the other 
hand, is limited to the inclusion of only pure hydrocarbon alkyl chains 
such as methyl, ethyl, propyl, cyclohexyl, isooctyl, tert-butyl, and the 
like. 
In addition to the alkylsulfonylamino groups described above the 
anthraquinone nucleus may be substituted with a variety of non-auxochromic 
groups, as is known in the art. Typical groups include: alkyl, fluoro, 
chloro, bromo, cyano, nitro, aminosulfonyl, and acylamino. Of these, 
halogens and acylamino groups are especially preferred, it being 
understood that the acyl moiety of the acylamino group may be derived from 
an optionally substituted alkyl, aryl or heterocyclic carboxylic acid or 
from an arenesulfonic acid. Anthraquinones containing both 
alkylsulfonylamino and alkyl- or arylcarbonylamino groups form a 
particularly preferred class. 
The methods of preparation of alkylsulfonylaminoanthraquinones are known 
generally in the art. For example, U.S. Pat. Nos. 3,072,683 and 3,324,150 
describe two procedures: the first involves coupling of a 
haloanthraquinone with an alkanesulfonamide in the presence of a copper 
catalyst; the second acylates an aminoanthraquinone with an alkanesulfonyl 
halide. We have found the latter method to be unsuitable for preparing 
1-(alkylsulfonylamino)anthraquinones with two or more carbon atoms in the 
alkyl chain, but the method may be effective in the case of 
1,4-diaminoanthraquinones. The coupling reaction is described in F. 
Ullmann and G. Billig, Ann., 381, 11 (1911) and the acylation and other 
related reactions in Houben-Weyl, "Methoden der organische Chemie", 4 
Auflage, Band IX, p. 398-400, p. 605-627. Acylating agents other than 
sulfonyl halides may be used. For example, sulfonic acid anhydrides, both 
symmetric and unsymmetric, sulfonic acid esters, and quaternary 
alkanesulfonylammonium salts may be effective. The preferred route to the 
alkylsulfonylaminoanthraquinones is copper catalyzed coupling of the 
sulfonamide with a haloanthraquinone. 
When substituents additional to alkylsulfonylamino are present in the 
anthraquinone they may be introduced by conventional procedures well known 
in the art. These substituents may be present in the molecule prior to 
introduction of the alkylsulfonylamino groups or may be incorporated when 
they are already present. Partial hydrolysis of the alkylsulfonylamino 
groups present, as described in British Pat. No. 445,192 for 
acylaminoanthraquinones, followed by elaboration of the resultant amino 
function may also be employed.

EXAMPLES 
Examples 1 to 12 describe preparations of representative compounds of this 
invention containing only alkylsulfonylamino substituents, while Examples 
13 to 15 present syntheses of compounds containing other additional 
substituents. The materials prepared in these examples were characterized 
by one or more of the following analytical techniques: .sup.1 H nuclear 
magnetic resonance, infrared, or ultraviolet-visible spectrometry, melting 
point. Considerable structural variation is possible within the scope of 
the invention, and the preparations should be regarded as illustrative but 
not limiting. 
EXAMPLE 1 
Preparation of 1-(n-octylsulfonylamino)anthraquinone. 
A 100ml round bottom flask, equipped with a magnetic stirrer and cooling 
condenser, was charged with 1-chloroanthraquinone (2.0g), 
n-octylsulfonamide (3.0g), copper acetate (0.8g), potassium carbonate 
(0.8g) and o-dichlorobenzene (25ml). This mixture was slowly heated to 
reflux. After 2.5 hours the reaction mixture was cooled and filtered. 
Methanol was then added to induce precipitation, and after filtration the 
solid was recrystallized from a mixture of dichloromethane and methanol to 
give a yellow product. 
EXAMPLE 2 
Preparation of 1,8-bis(benzylsulfonylamino)anthraquinone. 
A 100ml round bottom flask, equipped with a magnetic stirrer and cooling 
condenser, was charged with 1,8-dichloroanthraquinone (1.0g), 
benzylsulfonamide (4.0g), copper acetate monohydrate (1.0g), potassium 
carbonate (1.4g) and chlorobenzene (20ml). This mixture was refluxed for 
2.0 hours and cooled, whereupon methanol (100ml) was added to induce 
precipitation. The solid was collected, extracted with dichloromethane, 
treated with charcoal, and recrystallized from a mixture of methanol and 
dichloromethane to afford a yellow product. 
EXAMPLES 3-12 
The compounds tabulated below were prepared by methods similar to to those 
of Examples 1 and 2, using the appropriate reagents. 
Example 3 1-(ethylsulfonylamino)anthraquinone 
Example 4 1-(n-propylsulfonylamino)anthraquinone 
Example 5 1-(iso-propylsulfonylamino)anthraquinone 
Example 6 1-(n-butylsulfonylamino)anthraquinone 
Example 7 1-(n-hexadecylsulfonylamino)anthraquinone 
Example 8 1-(benzylsulfonylamino)anthraquinone 
Example 9 1,5-bis(n-octylsulfonylamino)anthraquinone 
Example 10 1,4-bis(n-octylsulfonylamino)anthraquinone 
Example 11 1,4,5-tris(n-octylsulfonylamino)anthraquinone 
Example 12 1,4,5,8-tetrakis(n-octylsulfonylamino)anthraquinone 
EXAMPLE 13 
Preparation of 1-n-octylsulfonylamino-5-chloroanthraquinone. 
1,5-dichloroanthraquinone (1.0g), n-octanesulfonamide (0.77g), potassium 
carbonate (1.0g), cupric acetate monohydrate (1.0g) and chlorobenzene 
(15ml) were refluxed for 4 hours. The solvent was evaporated at reduced 
pressure and the residue was extracted with toluene. After filtration the 
extract was separated by chromatography on silica using toluene as eluent 
to give the desired product as the second fraction. 
EXAMPLE 14 
Preparation of 
1-n-octylsulfonylamino-8-(1'-ethylhexanoylamino)anthraquinone 
1-(n-octylsulfonylamino)-8-aminoanthraquinone was prepared as follows. 
1-amino-8-chloroanthraquinone (1.0g), n-octanesulfonamide (1.0g), 
potassium carbonate (1.0g), cupric acetate monohydrate (0.85g) and 
chlorobenzene (16.0g) were refluxed for 5.5 hours. The cooled mixture was 
filtered and aqueous methanol was added to the filtrate. The supernatant 
liquid was decanted and the remaining oil was dissolved in 
dichloromethane. On addition of methanol and partial evaporation of the 
solvent, the product separated as a red solid. 
1-(n-octylsulfonylamino)-8-aminoanthraquinone (0.25g), 1-ethylhexanoyl 
chloride (0.5g) and nitrobenzene (5ml) were heated at reflux for 10 mins. 
After addition of methanol (10ml), the mixture was heated on a steam bath 
for a further 10 mins to destroy excess acid chloride. 0n evaporation of 
low-boiling material, the remaining liquid was diluted with toluene 
(100ml) and separated by chromatography on a silica gel column. 
Nitrobenzene eluted first, and the material eluted with a 50:50 mixture of 
toluene:ethyl acetate was collected. The solvent was evaporated and 
ethanol was added to the residue, which upon trituration afforded the 
product as a yellow solid. 
EXAMPLE 15 
Preparation of 
1-n-octylsulfonylamino-8-(4'-tolylsulfonyl)aminoanthraquinone 
1-(n-octylsulfonylamino)-8-aminoanthraquinone was prepared as in Example 
14. This material (0.30g), 4-toluenesulfonyl chloride (0.30g) and 
nitrobenzene (3ml) were refluxed for 10 mins. The reaction mixture was 
diluted with toluene (100ml) and separated by chromatography on silica 
gel. Evaporation of the yellow fraction eluted with toluene gave the 
product as a golden solid. 
The improved coloring abilities of the dyes of this invention, which result 
from their enhanced solubility, are described in Examples 16 and 17. Alkyl 
derivatives of three or more carbon atoms give superior solubilities 
compared to corresponding aryl derivatives, both in extremely non-polar 
and in moderately polar solvents. 
EXAMPLE 16 
Solubility of 1-(alkylsulfonylamino)anthraquinones in n-heptane. 
The sulfonylaminoanthraquinones tabulated below were suspended in n-heptane 
and mechanically shaken. After filtration, the peak absorbances of the 
supernatant solutions were determined using a 1 cm path length, with the 
results below. 
______________________________________ 
1-Substituent Absorbance 
______________________________________ 
4'-tolyl 0.15 
methyl 0.10 
ethyl 0.19 
-n-octyl 0.74 
______________________________________ 
EXAMPLE 17 
Solubility of bis(alkylsulfonylamino)anthraquinones in n-butyl acetate. 
The sulfonylaminoanthraquinones tabulated below were suspended in n-butyl 
acetate and mechanically shaken. After filtration, the peak absorbances of 
the supernatant solutions were determined and corrected to a 1 cm path 
length, with the results below. 
______________________________________ 
Substituents Absorbance 
______________________________________ 
1,5-bis(4'-tolyl) 
&lt;0.1 
1,5-bis( -n-octyl) 
1.4 
1,4-bis(mesityl) 
0.7 
1,4-bis(4'-tolyl) 
4.8 
1,4-bis( -n-octyl) 
12.7 
______________________________________ 
The reduction in melting points obtained with the 
alkylsulfonylaminoanthraquinones of this invention is shown in Example 18 
by comparison to analogous arylsulfonylamino derivatives. It can be seen 
that useful reductions in melting point can be achieved with alkyl groups 
as small as ethyl, and that substitution in the alkyl group can be 
tolerated without detrimental effect. 
EXAMPLE 18 
Melting points of dyes 
Melting points were determined for the tabulated alkyl- and 
arylsulfonylaminoanthraquinones by differential scanning calorimetry with 
a heating rate of 10.degree. C. per minute. Certain of these materials 
also exhibited thermal transitions other than melting. 
______________________________________ 
Substituent Melting point (.degree.C.) 
______________________________________ 
1-methyl 217 
1-ethyl 191 
1- -n-propyl 168 
1- -n-butyl 140 
1- -n-octyl 135 
1- -n-hexadecyl 
131 
1-benzyl 190 
1-(mesityl) 249 
1-(4'-tolyl) 234 
1,4-bis(4'-tolyl) 
248 
1,4-bis( -n-octyl) 
178 
______________________________________ 
The practical utility of control of melting point in the compounds of this 
invention is illustrated by application to a thermal dye transfer imaging 
system in Example 19. 
EXAMPLE 19 
Thermal transfer 
A coating solution was prepared as follows: 
1,4-bis(n-octylsulfonylamino)anthraquinone (0.030 gm); Goodrich 
Temprite.TM. 678.times.512 chlorinated polyvinyl chloride (0.025 gm); 
60/40 blend of octadecyl acrylate and acrylic acid (0.007 gm); 
tetrahydrofuran (1.50 gm); 2-butanone (0.10 gm). The solution was coated 
on 6 micron polyester film using a number 8 wire-wound coating rod and 
dried in a current of air at ambient temperature. This dye donor sheet was 
contacted with a Hitachi VY-S Video Print Paper.TM. receptor sheet and 
imaged with a Kyocera KMT.TM. thermal print head. A satisfactory orange 
image was obtained with good transfer efficiency. 
The image formed by thermal transfer in the above Example 19 was evaluated 
for heat and light stability as described in Example 20. The heat fastness 
and fade resistance of the image were excellent. As is taught in the art, 
the presence of the sulfonylamino group may also be expected to confer 
good sublimation resistance. 
EXAMPLE 20 
Heat and light stability of the thermal image 
The image obtained in Example 19 was exposed in an Atlas UVICON.TM. at 350 
nm and 50.degree. C. A portion was screened from the light by a thick, 
opaque, black-film, and was thus subject only to heat. For both 
light-struck and screened portions of the image the change in (L,a,b) 
color coordinates, DELTA E, was measured as a function of time, and is 
tabulated below. A DELTA E of 2.0 or less is not perceptible to the eye. 
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DELTA E 
Exposure (hours) 
Heat Only Heat and Light 
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24 0.77 0.85 
48 0.66 0.92 
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Anthraquinone dyes are known to exhibit fluorescence to a greater or lesser 
degree. The peak wavelength of the fluorescence emission is Stokes shifted 
to the red of the peak absorption wavelength. The amount of this Stokes 
shift is typically about 3000 to 6000 wavenumbers in aprotic solvents (H. 
Inoue et al., J. Phys. Chem., 86, 3184 (1982)). It is, therefore, 
surprising that certain of the compounds of this invention exhibit 
exceptionally large Stokes shifts in excess of 7000 wavenumbers. Some 
representative results for anthraquinones substituted solely with 
alkylsulfonylamino groups are presented in Example 21. The exceptional 
Stokes shift is seen to be associated with a 1-mono-substitution and with 
a 1,5- and 1,8-di-substitution pattern. A large Stokes shift can be 
valuable in the design of radiation sensors and detectors, for example. 
EXAMPLE 21 
Stokes shifts of alkylsultonylamino-anthraquinones 
Absorption and emission spectra of the tabulated compounds were determined 
in dilute methylene chloride solution. The Stokes shifts were determined 
from the absorption and emission maxima by difference. 
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Substitution Pattern 
Stokes Shift (wavenumbers) 
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1- -n-octyl 9200 
1,4-bis( -n-octyl) 
4130 
1,5-bis( -n-octyl) 
7500 
1,8-bis(benzyl) 4530, 7225 (dual emission) 
1,3,5-tris(n-octyl) 
3005 
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