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Description  |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to heat-sensitive recording elements useful for
making color images, to a method of imaging using said elements and to
novel organic compounds useful as the image-forming materials in said
heat-sensitive recording elements.
2. Description of the Prior Art
A variety of thermal imaging systems for producing color images have been
proposed, and several have been mentioned in Kosar, J., Light-Sensitive
Systems: Chemistry and Application of Nonsilver Halide Photographic
Processes, New York, John Wiley and Sons, Inc., 1965, pp. 402-19. In one
type of heat sensitive recording system, a first sheet containing a first
reagent is superposed with a second sheet containing a second reagent and
one of the reagents is melted or vaporized by the imagewise application of
heat and transferred for reaction with the other reagent to form a color
image. In another type of "transferring system", images are formed by
sequentially transferring two or more dyes carried on separate donor
sheets to a common receptor sheet by melting or volatilization. In thermal
imaging systems of the "self-containing" type, a single sheet is used and
the imagewise heating of the heat-sensitive sheet produces a color image,
for example, by rendering a coating layer transparent to reveal the color
of a background layer, by initiating the chemical reaction of two or more
reagents to form a colored product or by bleaching, coloring or changing
the color of a single reagent.
A number of compounds of the latter type, that is, single compounds which
undergo a color change upon application of heat have been disclosed. U.S.
Pat. No. 3,488,705 discloses thermally unstable organic acid salts of
triarylmethane dyes useful in electrophotographic elements as sensitizing
dyes that are decomposed and bleached upon heating. U.S. Pat. No.
3,745,009 reissued as U.S. Pat. No. Re. 29,168 and U.S. Pat. No. 3,832,212
disclose heat-sensitive compounds for thermography containing a
heterocyclic nitrogen atom substituted with an --OR group, for example, a
carbonate group that decolorize by undergoing homolytic or heterolytic
cleavage of the nitrogen-oxygen bond upon heating to produce an RO+ ion or
RO' radical and a dye base or dye radical which may in part fragment
further. U.S. Pat. No. 4,380,629 discloses styryl-like compounds which
undergo coloration or bleaching, reversibly or irreversibly via
ring-opening and ring-closing in response to activating energies such as
light, heat, electric potential, and copending U.S. Patent application
Ser. No. 646,771 of Alan L. Borror, Ernest W. Ellis and Donald A. McGowan
filed Sept. 4, 1984, now U.S. Pat. No. 4602263 discloses organic compounds
that undergo color formation or color bleaching by an irreversible
unimolecular fragmentation of at least one thermally unstable carbamate
moiety, for example, triarylmethane compounds including bridged
triarylmethane compounds comprising a carbamate moiety, such as,
##STR1##
SUMMARY OF THE INVENTION
The present invention is concerned with thermal imaging systems employing
certain di- and triarylmethane compounds comprising a moiety ring-closed
on the meso carbon atom, i.e., the methane carbon atom, that are
substantially colorless initially and become colored as a result of a
thermal fragmentation reaction to unmask a group for effecting an
intramolecular nucleophilic substitution reaction whereby the di- or
triarylmethane compound becomes irreversably ring-opened. In a preferred
embodiment, the ring-closed moiety is bonded to the meso carbon atom
directly through a nitrogen atom and upon heating undergoes intramolecular
acylation on said nitrogen atom whereby a new moiety is formed which
cannot bond to the meso carbon atom and which irreversibly "traps" the di-
or triarylmethane compound in an open, colored form.
Because the subject compounds undergo an intramolecular reaction to effect
a color change, coloration can be achieved without the need for
transferring a reagent or for contacting two reagents, and because
coloration can be achieved at moderately elevated temperatures, any
conventional heating means for effecting imagewise heating may be
employed. Also, di- and triarylmethane compounds useful in the subject
thermal imaging systems may be selected to provide a wide range of colors
including black as may be desired not only in the production of
monochromes and bichromes but in the production of full color images as
well.
It is, therefore, the primary object of the present invention to provide a
method of thermal imaging for producing color images.
It is another object of the present invention to provide heat-sensitive
recording elements useful in said method.
It is yet another object of the present invention to provide a new class of
heat-sensitive compounds useful in the subject thermal imaging systems.
Other objects of the invention will in part be obvious and will in part
appear hereinafter.
The invention accordingly comprises the methods involving the several steps
and the relation and order of one or more of such steps with respect to
each of the others, and the products and compositions possessing the
features, properties and the relation of elements which are exemplified in
the following detailed disclosure, and the scope of the application of
which will be indicated in the claims.
For a fuller understanding of the nature and objects of the invention,
reference should be had to the following detailed description.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In accordance with the present invention, a method of thermal imaging is
provided which comprises heating imagewise a heat-sensitive element
comprising a support carrying at least one layer of a colorless di- or
triarylmethane compound possessing within its di- or triarylmethane
structure an aryl group substituted on a carbon atom in the ortho position
to the meso carbon atom with a moiety ring-closed on the meso carbon atom
to form a 5- or 6-membered ring, said moiety possessing a nitrogen atom
bonded directly to said meso carbon atom and said nitrogen atom being
bound to a group, e.g., a phenyl group substituted with a masked acyl
substituent that undergoes fragmentation upon heating to liberate the acyl
group for effecting intramolecular acylation of said nitrogen atom to form
a new group in the ortho position that cannot bond to the meso carbon
atom, said imagewise heating effecting the formation of said new group in
the ortho position whereby said di- or triarylmethane compound is rendered
colored in an imagewise pattern corresponding to said imagewise heating.
Preferably, the masked acylating substituent is a masked carbonyl group
that undergoes thermal fragmentation in the presence of heat to liberate a
reactive carbonyl group for effecting said intramolecular acylation
reaction.
Typical diarylmethane and triarylmethane compounds that may be used in the
present invention are the novel color-forming compounds represented by the
formula
##STR2##
wherein ring B represents a carbocyclic aryl ring, e.g., of the benzene or
naphthalene series or a heterocyclic aryl ring, e.g., pyridine or
pyrimidine; C.sub.1 represents the meso carbon atom; X represents
##STR3##
Y represents a substituent that undergoes fragmentation upon heating to
liberate a group capable of acylating said nitrogen atom; E is hydrogen,
an electron donating group, an electron-withdrawing group or a group,
either an electron-donating group or an electron-neutral group, that
undergoes fragmentation upon heating to liberate a new group that renders
the overall reaction more efficient, preferably an electron-withdrawing
group; s is 0 or 1; and Z and Z' taken individually represent the moieties
to complete the auxochromophoric system of a diarylmethane or a
triarylmethane dye when said N-containing ring is open and Z and Z' when
taken together represent the bridged moieties to complete the
auxochromophoric system of a bridged triarylmethane dye when said
N-containing ring is open. In a preferred embodiment, B represents a
benzene ring and Z and Z' taken individually represent the aryl moieties,
the same or different, to complete the auxochromophoric system of a
triarylmethane dye when said N-containing ring is open and Z and Z' when
taken together represent the bridged aryl moieties to complete the
auxochromophoric system of a bridged triarylmethane dye when said
N-containing ring is open. Usually, at least one of Z and Z' whether taken
individually or together possesses as an auxochromic substituent, a
nitrogen, oxygen or sulfur atom or a group of atoms containing nitrogen,
oxygen or sulfur.
In the triarylmethane compounds represented in formula I above, the aryl
moieties Z and Z', when taken individually, may be the same or different
and typically represent heterocyclic aryl groups containing nitrogen,
oxygen or sulfur as the heterocyclic atom, particularly N-heterocyclic
aryl groups such as julolidin-3-yl, indol-3-yl, pyrr-2-yl, carbazol-3-yl,
and indolin-5-yl wherein the N atom of the indolyl, pyrryl, carbazolyl and
indolinyl groups may be substituted with hydrogen or alkyl having 1 to 6
carbon atoms, or the aryl moieties Z and Z' typically may be carbocyclic
aryl, particularly phenyl or naphthyl groups which include an
appropriately positioned auxochromic substituent, i.e., an atom or group
that produces an auxochromic effect, which substituent is usually
positioned para to the meso carbon atom. Typically, Z and Z' when taken
together represent aryl groups bridged by a heteroatom, such as, oxygen,
sulfur or nitrogen to form, for example, 4H-chromeno [2,3-C] pyrazole ad
particularly represent carbocyclic aryl groups, such as, phenyl groups
bridged with a heteroatom, preferably oxygen, sulfur or nitrogen
substituted with hydrogen or an alkyl group having 1 to 6 carbon atoms to
provide a xanthene, thioxanthene or an acridine dye, which dyes possess an
auxochromic substituent(s) para to the meso carbon atom, i.e., in the
3-position or in the 3,6-positions or meta and para to the meso carbon
atom, i.e., in the 3,7-positions.
In the diarylmethane compounds, one of Z and Z' may be heterocyclic aryl or
carbocyclic aryl as discussed above and the other of Z and Z' may be, for
example, phenoxy, thiophenoxy, alkoxy containing 1 to 20 carbon atoms,
alkylthio containing 1 to 20 carbon atoms, --N,N-(disubstituted)amino
wherein each said substituent may be alkyl containing 1 to 20 carbon
atoms, carbocyclic aryl containing 6 to 12 carbon atoms, aralkyl
containing 7 to 15 carbon atoms particularly phenyl- and
naphthyl-substituted alkyl or alkaryl containing 7 to 15 carbon atoms
particularly alkyl-substituted phenyl and naphthyl. Representative alkyl
groups include methyl, butyl, hexyl and octadecyl and representative aryl
groups include phenyl and naphthyl. Representative alkaryl groups include
p-octylphenyl, o-methylnaphthyl and p-hexylphenyl, and representative
aralkyl groups include phenethyl, benzyl and naphthylmethyl.
Examples of useful auxochromic substituents include --OR.sub.1 wherein
R.sub.1 is hydrogen, alkyl usually having 1 to 6 carbon atoms, aralkyl
usually having 7 to 15 carbon atoms, alkaryl usually having 7 to 15 carbon
atoms or carbocyclic aryl usually having 6 to 12 carbon atoms; --SR.sub.2
wherein R.sub.2 has the same meaning given for R.sub.1 ; --NR.sub.3
R.sub.4 wherein R.sub.3 and R.sub.4 each represent hydrogen, alkyl usually
having 1 to 6 carbon atoms, .beta.-substituted ethyl, cycloalkyl usually
having 5 to 7 carbon atoms, aralkyl usually having 7 to 15 carbon atoms,
alkaryl usually having 7 to 15 carbon atoms or
##STR4##
wherein R.sub.5 and R.sub.6 each are hydrogen, alkyl usually having 1 to 6
carbon atoms, halo such as chloro, bromo, fluoro and iodo, nitro, cyano,
alkoxycarbonyl wherein said alkoxy has 1 to 6 carbon atoms, sulfonamido
(--NHSO.sub.2 R.sub.0), sulfamoyl (--SO.sub.2 NHR.sub.0), sulfonyl
(--SO.sub.2 R.sub.0), acyl (--COR.sub.0) or carbamyl (--CONR.sub.0)
wherein R.sub.0 usually is alkyl having 1 to 6 carbon atoms, benzyl or
phenyl and R.sub.3 and R.sub.4 taken together represent the atoms
necessary to complete a heterocyclic ring usually piperidino, pyrrolidino,
N-methylpiperidino, morpholino or
##STR5##
wherein q is an integer 2 to 5 and R.sub.7 has the same meaning as
R.sub.5,
##STR6##
wherein R.sub.8 and R.sub.9 each are hydrogen, alkyl usually having 1 to 6
carbon atoms or
##STR7##
wherein R.sub.11 and R.sub.12 have the same meaning as R.sub.5 and R.sub.6
and R.sub.10 is --COR.sub.13, --CSR.sub.13 or --SO.sub.2 R.sub.13 wherein
R.sub.13 is hydrogen, alkyl usually having 1 to 6 carbon atoms, phenyl,
--NH.sub.2, --NHR.sub.14, --N(R.sub.14).sub.2 or --OR.sub.14 wherein
R.sub.14 is hydrogen, alkyl usually containing 1 to 6 carbon atoms or
phenyl. Representative alkyl groups include methyl, ethyl, propyl, butyl
and hexyl. Representative .beta.-substituted ethyl groups include
.beta.-methoxymethoxyethyl and .beta.-2'-tetrahydropyranyloxyethyl.
Representative aralkyl groups include phenyl and naphthyl-substituted
alkyl, such as, benzyl, phenethyl and naphthylmethyl and representative
alkaryl groups include alkyl-substituted phenyl and naphthyl, such as,
o-methylphenyl, o-methylnaphthyl and p-hexylphenyl. Representative
carbocyclic aryl groups include phenyl and naphthyl and representative
cycloalkyl groups include cyclopentyl, cyclohexyl and cycloheptyl. It will
be appreciated that the auxochromic substituent(s) will be selected for a
given diarylmethane, triarylmethane or bridged triarylmethane compound to
provide the desired chromophore color upon opening of the N-containing
ring and to achieve facile color formation.
Representative electron-donating groups for E include alkyl groups such as
methyl, ethyl, t-butyl and hexyl, alkoxy groups such as methoxy, ethoxy,
propoxy and butoxy, and amino, (monoalkyl)amino and (dialkyl)amino wherein
said alkyls each contain 1 to 6 carbon atoms. Representative
electron-withdrawing groups include cyano, dibenzylsulfonamido,
dimethylsulfonamido, methylsulfonyl, phenylsulfonyl, p-tolylsulfonyl,
carboxy, acetyl, carboethoxy, carbamyl, isothiocyano, benzoyl,
trifluoromethyl and halo, e.g., chloro, bromo, fluoro and iodo. Useful
electron-donating or electron-neutral groups that undergo fragmentation
upon heating to liberate an electron-withdrawing group include
##STR8##
wherein p is an integer 1 to 4, --CH--O--CH.sub.2 --O--R' and
##STR9##
wherein R' is alkyl usually having 1 to 20 carbon atoms, aryl usually
having 6 to 12 carbon atoms, aralkyl usually having 7 to 15 carbon atoms
and alkaryl usually having 7 to 15 carbon atoms and R" and R'" each are
hydrogen, alkyl usually having 1 to 6 carbon atoms, aryl having 6 to 12
carbon atoms, aralkyl usually having 7 to 15 carbon atoms and alkaryl
usually having 7 to 15 carbon atoms. Typical alkyl, aryl, aralkyl and
alkaryl groups for R', R" and R'" are those mentioned above.
As used herein and as well known in the art, an electron-withdrawing group
is a group having a positive sigma value. An electron-donating group is a
group having a negative sigma value and an electron-neutral group is a
group having a sigma value of 0. In addition to the groups specified
above, a number of other groups together with their sigma values are
listed in Lang's Handbook of Chemistry and in H. H. Jaffe, A Reexamination
of the Hammett Equation, Chem. Reviews, 1953, pp. 222-23. It will be
understood that the electron-donating and the electron-neutral groups
selected to provide an electron-withdrawing group will undergo
fragmentation under the same heating conditions, i.e., in the same
temperature range as required for the fragmentation reaction that unmasks
the group for effecting the intramolecular nucleophilic substitution
reaction.
In addition to the auxochromic substituents, Z and/or Z' and/or the ring B
of the ring-closing moiety may possess one or more additional substituents
as may be desired that do not interfere with the intended utility for the
dye. Typical substituents include carboxy; hydroxy; cyano; thiocyano;
mercapto; sulfo; nitro; sulfonamido (--NHSO.sub.2 R.sub.0); sulfamoyl
(--SO.sub.2 NHR.sub.0); sulfonyl (--SO.sub.2 R.sub.0); acyl (--COR.sub.0);
carbamyl (--CONR.sub.0); halomethyl such as trifluoromethyl; alkyl usually
having 1 to 20 carbon atoms such as methyl, octyl, hexadecyl; alkoxy
usually having 1 to 20 carbon atoms such as methoxy, ethoxy, propoxy and
butoxy; alkoxycarbonyl having 1 to 6 carbon atoms such as methoxy- and
ethoxycarbonyl; aralkyl usually having 7 to 15 carbon atoms, for example,
phenyl or naphthyl-substituted alkyl such as benzyl, phenethyl and
naphthylmethyl; alkaryl usually having 7 to 15 carbon atoms, for example,
alkyl-substituted phenyl or naphthyl such as o-methylphenyl,
o-methylnaphthyl and p-hexylphenyl; aralkyloxy usually having 7 to 15
carbon atoms, for example, phenyl or naphthyl-substituted alkoxy, such as
benzyloxy, phenethyloxy and naphthylmethyloxy; aryloxy usually containing
6 to 12 carbon atoms such as phenoxy and naphthoxy; thioalkyl groups
usually having 1 to 20 carbon atoms such as methylthio, ethylthio and
hexylthio; thioaryl and thioaralkyl groups containing up to 15 carbon
atoms such as phenylthio, naphthylthio, benzylthio and phenethylthio, halo
such as chloro, bromo, fluoro and iodo; amino including mono- and
disubstituted amino such as --NR.sub.8 R.sub.9 wherein R.sub.8 and R.sub.9
each are hydrogen, alkyl usually having 1 to 20 carbon atoms, aralkyl
usually having 7 to 15 carbon atoms, alkaryl usually having 7 to 15 carbon
atoms, and carbocyclic aryl usually having 6 to 12 carbon atoms; and a
fused substituent such as a fused benzene ring.
Preferred compounds of the present invention are those represented by the
formula
##STR10##
wherein C.sub.1 represents the meso carbon atom; X represents
##STR11##
E is hydrogen, an electron-donating group, an electron-withdrawing group
or a group, either an electron-donating group or an electron-neutral
group, that undergoes fragmentation upon heating to liberate an
electron-withdrawing group; L is a leaving group that departs upon thermal
fragmentation to unmask --N.dbd.C.dbd.O; G is hydrogen, alkyl having 1 to
6 carbon atoms, alkoxy having 1 to 6 carbon atoms, alkoxycarbonyl having 1
to 6 carbon atoms, carboxy, cyano, thiocyano, nitro, sulfo, sulfonamido,
sulfamoyl, sulfonyl, acyl, carbamyl, halo, --OR wherein R is hydrogen,
alkyl having 1 to 6 carbon atoms, benzyl or phenyl, --SR.sup.0 wherein
R.sup.0 has the same meaning as R or --NR.sup.5 R.sup.6 wherein R.sup.5
and R.sup.6 each are hydrogen, alkyl having 1 to 6 carbon atoms,
.beta.-substituted ethyl, benzyl or phenyl; A and A', the same or
different, are selected from phenyl substituted in the 4-position with
--OR.sup.1 wherein R.sup.1 has the same meaning as R, --SR.sup.2 wherein
R.sup.2 has the same meaning as R or --NR.sup.5 R.sup.6 wherein R.sup.5
and R.sup.6 have the same meaning given above and substituted in the 2-,
3-, 5- and 6-positions with hydrogen, alkyl having 1 to 6 carbon atoms,
alkoxy having 1 to 6 carbon atoms or chloro or substituted in the 5- and
6-positions with a fused benzene ring; indol-3-yl substituted in the 1 and
2 positions with hydrogen, alkyl having 1 to 6 carbon atoms, benzyl or
phenyl; pyrr-2-yl substituted in the 1-position with hydrogen, alkyl
having 1 to 6 carbon atoms, benzyl or phenyl; and carbazol-3-yl
substituted in the 9-position with hydrogen, alkyl having 1 to 6 carbon
atoms, benzyl or phenyl; and A and A' taken together represent phenyl
groups bridged by a heteroatom selected from oxygen, sulfur and nitrogen
substituted with hydrogen or alkyl having 1 to 6 carbon atoms to form
xanthene, thioxanthene or acridine (a) substituted in the 3- and
6-positions with a group, the same or different, selected from --OR.sup.3
wherein R.sup.3 has the same meaning as R, --SR.sup.4 wherein R.sup.4 has
the same meaning as R and --NR.sup.7 R.sup.8 wherein R.sup.7 is hydrogen
or alkyl having 1 to 6 carbon atoms and R.sup.8 is alkyl having 1 to 6
carbon atoms, benzyl or
##STR12##
wherein R.sup.9 and R.sup.10 each are hydrogen, alkyl usually having 1 to
6 carbon atoms, alkoxy having 1 to 6 carbon atoms, chloro, nitro, cyano,
alkoxycarbonyl wherein said alkoxy has 1 to 6 carbon atoms, sulfonamido,
sulfamoyl, sulfonyl, acyl, or carbamyl and R.sup.9 and R.sup.10 taken
together represent indolino and
##STR13##
wherein R.sup.11 and R.sup.12 each are hydrogen, alkyl having 1 to 6
carbon atoms or
##STR14##
wherein R.sup.14 and R.sup.15 have the same meaning as R.sup.9 and
R.sup.10 and R.sup.13 is --COR.sup.16 wherein R.sup.16 is hydrogen, alkyl
having 1 to 6 carbon atoms or phenyl and substituted in the 1-, 2-, 4-,
5-, 7- and 8-positions with hydrogen, alkyl having 1 to 6 carbon atoms,
alkoxy having 1 to 6 carbon atoms or chloro or (b) substituted in the
3-position with --NR.sup.17 R.sup.18 wherein R.sup.17 is hydrogen, alkyl
having 1 to 6 carbon atoms, cycloalkyl having 5 to 7 carbon atoms, benzyl
or phenyl and R.sup.18 is alkyl having 1 to 6 carbon atoms, cycloalkyl
having 5 to 7 carbon atoms, benzyl or phenyl and R.sup.17 and R.sup.18
taken together represent piperidino, pyrrolidino, N-methylpiperidino or
indolino and (1) substituted in the 7- and 8-positions with a fused
benzene ring or (2) substituted in the 7-position with hydrogen,
--NR.sup.17 R.sup.18 wherein R.sup.17 and R.sup.18 have the same meaning
given above, alkyl having 1 to 6 carbon atoms, alkoxy having 1 to 6 carbon
atoms or chloro and substituted in the 1-, 2-, 4-, 5-, 6- and 8-positions
with hydrogen, alkyl having 1 to 6 carbon atoms, alkoxy having 1 to 6
carbon atoms or chloro. Preferably, X is
##STR15##
Leaving groups are well known and various leaving groups have been reported
by Charles J. M. Stirling. Acc. Chem. Res. 12,198 (1979) and Charles J. M.
Stirling, et al., J. Chem. Soc. Chem. Commum., 941 (1975). Examples of
leaving groups that can be employed as L include imidazolyl; --SMe; --SPh;
--SO.sub.2 Me; --SO.sub.2 Ph; --SePh; --OPh; --OMe; --P(O)(OEt).sub.2 ;
--C(Me).sub.2 NO.sub.2, --N(Me)Ts; --N(Me)Ac; --N(Ph)Ac; --N(Ph)Ts;
--N(Ph)CO.sub.2 CH.sub.2 Ph; and --N(Me)CO.sub.2 Ph wherein Me, Et, Ph, Ac
and Ts represent methyl, ethyl, phenyl, acetyl and tosyl, respectively.
The Ph and Ts groups may be substituted with one or more substituents, for
example, alkyl, alkoxy, halo, carboxy, nitro, cyano, --SO.sub.2 alkyl,
--SO.sub.2 phenyl, tosyl and N,N-(dialkyl)amino. Preferably, L is phenoxy
unsubstituted or substituted with carboxy, nitro, cyano, halo, such as,
chloro, bromo, iodo or fluoro, alkyl having 1 to 6 carbon atoms, alkoxy
having 1 to 6 carbon atoms, N,N-(dialkyl)amino wherein said alkyl contains
1 to 6 carbon atoms, --SO.sub.2 phenyl, --SO.sub.2 alkyl containing 1 to 6
carbon atoms or tosyl.
The compounds of the foregoing formula may be synthesized in a conventional
manner by treating a di- or triarylmethane compound possessing, for
example, a lactone or sultone ring-closing moiety with phosphorus
oxychloride or other suitable reagent to give the corresponding carbonyl
or sulfonyl chloride followed by reacting with an ortho-phenylene diamine
derivative and then with the appropriate chloroformate derivative to give
the desired N-substituted lactam or sultam, by treating a di- or
triarylmethane compound possessing an unsubstituted lactam or sultam
ring-closing moiety with a base, such as sodium hydride, to give the
corresponding lactam or sultam anion followed by reacting with an
ortho-fluoro-nitrobenzene derivative, reducing the nitro group and finally
reacting the resulting amino group with the appropriate chloroformate
derivative to give the desired N-substituted lactamor sultam, or by
reducing both the lactone and the dye to the leuco form followed by
halogenating or tosylating the alcohol and reacting the latter compound
with an ortho-substituted aniline derivative and then oxidizing the leuco
dye to give the desired N-substituted benzylamine product. The following
represents a schematic illustration of the above-described syntheses.
##STR16##
wherein Z and Z' have the same meaning given above.
Various diarylmethane and triarylmethane dyes including bridged
triarylmethanes possessing, for example, a lactone or sultone ring-closing
moiety or capable of being derivatized with these moieties have been
disclosed in the art. For example, various such dyes have been described
in Venkataraman, K., The Chemistry of Synthetic Dyes, Academic Press,
Inc., New York, 1952, pp 705-760 and 1111 and in U.S. Pat. Nos. 3,491,111;
3,491,112; 3,491,116; 3,509,173; 3,509,174; 3,514,310, 3,514,311,
3,775,424, 3,853,869, 3,872,046, 3,931,227, 3,959,571, 4,341,403,
4,304,833, 4,354,017, 4,535,172 and 4,535,348.
If the starting materials possess hydroxy, carboxy, mercapto or other
substituents that may require blocking during synthesis, conventional
protecting groups may be employed as described by McOmie, J. F. W.,
Protective Groups in Organic Chemistry, Plenum Press, New York, 1973 and
by Greene, Theodora W., Protective Groups in Organic Synthesis, John Wiley
& Sons, New York, 1981.
The following examples are given to further illustrate the preparation of
the foregoing compounds.
EXAMPLE 1
Preparation of the compound having the formula
##STR17##
To 2.1 g of the compound having the formula
##STR18##
was added 30 ml of phosphorus oxychloride and the solution was stirred at
60.degree. C. for about 4 hours. The excess phosphorus oxychloride was
stripped off and the residue was treated with two 30 ml portions of
toluene, each subsequently evaporated in a vacuum. The resulting solid was
dissolved in methylene chloride and the resulting solution was added
dropwise to 5 g of ortho-phenylene diamine and 440 mg of
4-dimethylaminopyridine dissolved in methylene chloride at ice bath
temperature. After stirring overnight, the reaction mixture was combined
with another reaction mixture prepared in substantially the same manner
except that 5 g of Compound 1A, 75 ml of phosphorus oxychloride and 10 g
of ortho-phenylene diamine were employed without the
dimethylaminopyridine. The combined reaction mixtures were purified by
high pressure liquid chromotography to yield 1.5 g of the following white
compound.
##STR19##
0.5 gram of Compound 1B was dissolved in 6 ml of methylene chloride. Sodium
bicarbonate (1 equivalent) was added and the resulting solution was
stirred at room temperature vigorously while one equivalent (0.9 ml) of
phenylchloroformate dissolved in 2 ml of methylene chloride was added
dropwise. Another addition of 3 equivalents each of sodium bicarbonate and
phenylchloroformate were required to drive the reaction to completion.
Silica gel TLC of a sample using 25% ethylacetate in hexane showed that
the reaction was substantially complete and gave a colorless compound that
became intensely magenta upon heating. The reaction mixture was filtered,
evaporated and redissolved in a small amount of methylene chloride for
purification by silica gel medium pressure liquid chromotography to yield
500 mg of the title compound as a slightly pink solid. M/e.sup.+ 826.
EXAMPLE 2
##STR20##
To a solution of 66 g (0.09 mole) of Compound 2A of the following formula
dissolved in 450 ml of methylene chloride
##STR21##
was added 20.56 ml (0.216 mole) of dimethyl sulfate and 3.06 g of
tetrabutylammonium hydrogen sulfate. A sodium hydroxide solution, 9.24 g
(0.231 mole) in 150 ml of water, was added to the reaction mixture
dropwise over 90 minutes. The resulting mixture was stirred at room
temperature for four hours after the addition was complete. Another
solution of 16.5 g (0.42 mole) of sodium hydroxide in 280 ml of water was
added in one portion to the reaction mixture which was then stirred for an
additional five hours. The organic layer was separated and diluted with
330 ml of methylene chloride. This solution was then dried by distilling
off approximately 300 ml of solvent and the residue comprising the
corresponding bis N-methyl compound (Compound 2B) was cooled to room
temperature.
##STR22##
To the dried residue (2B) was added 21.9 ml (0.234 mole) of phosphorus
oxychloride and 1.5 ml (0.015 mole) of N-methylpyrrolidinone. The reaction
mixture was heated to reflux and stirred for six hours and then cooled to
room temperature. 22 g (0.18 mole) of 4-dimethylaminopyridine in a minimum
amount of methylene chloride was added dropwise followed by the
portionwise addition of 48 g (0.45 mole--5 equivalents) of o-phenylene
diamine in 400 ml of methylene chloride over 30 minutes. The reaction
temperature during and after addition was maintained between 20.degree.
and 25.degree. C. The reaction was stirred at 20.degree. C. for four hours
and then at 40.degree. C. for two hours. Silica gel TLC of a sample in 20%
ethylacetate in hexane indicated that the reaction was substantially
complete. The reaction mixture was filtered, reduced in volume to about
200 ml and purified by silica gel high pressure liquid chromatography to
give the following compound.
##STR23##
4.2 grams (0.006 mole) of Compound 2C was dissolved in a minimum amount of
methylene chloride and stirred briskly with 2 g. of sodium bicarbonate at
room temperature under nitrogen. 3.0 ml of phenylchloroformate dissolved
in a few mls of methylene chloride was added dropwise over 30 minutes. The
reaction mixture turned an intense magenta color. After several hours of
stirring, silica gel TLC of a sample using 25% ethylacetate in hexane
showed substantially complete conversion to a new colorless compound which
turned magenta upon heating the TLC plate to 130.degree.-180.degree. C.
The reaction mixture was purified by silica gel chromotography (elution
with hexane followed by 5%, 10%, 15%, 20%, 25% ethylacetate in hexane) to
give the title compound as a light pink solid (3.74 g; 76% by weight
yield). M/e.sup.+ 826
EXAMPLE 3
Preparation of the compound having the formula
##STR24##
8 grams of the compound having the fomula
##STR25##
and 5.84 g of phosphorus oxychloride dissolved in 120 ml of chloroform
were refluxed for 5 hours and then allowed to stand at room temperature
overnight. The reaction mixture was stirred vigorously with 42 ml water
for about 20 minutes, then transferred to a separatory funnel and the
organic layer separated. The chloroform layer was washed twice with 50 ml
portions of water then dried over magnesium sulfate. After filtering to
remove the magnesium sulfate, the solution was cooled to 0.degree. C. and
8.55 g of 4-dimethylaminopyridine was added portionwise over 10 minutes. A
small amount of chloroform was added for dilution. Then 7.56 g of
o-phenylene diamine dissolved in a minimum amount of chloroform was added
dropwise to the solution over 30 minutes. The reaction mixture was allowed
to come to room temperature and stirring was continued for 4 hours. The
reaction mixture was filtered and the volume reduced to about 80 ml. The
mixture was then injected onto a high pressure silica gel column and
eluted with 2 liters of hexane followed by 2 liters each of 5%
ethylacetate/hexane, 10% ethylacetate/hexane, 15% ethylacetate/hexane and
20% ethylacetate/hexane. 770 mg of the following compound was recovered.
##STR26##
770 mgs. of Compound 3B was dissolved in a minimum of methylene chloride.
Sodium bicarbonate (4 equivalents) was added and the reaction mixture was
stirred biskly under nitrogen. Four equivalents of phenylchloroformate was
added dropwise over 30 minutes at room temperature and the reaction was
allowed to stir overnight. The reaction mixture was filtered and applied
to a medium pressure silica gel column conditioned with hexane and eluted
with hexane, 5% ethylacetate/hexane, 10% ethylacetate/hexane, 15%
ethylacetate/hexane and 20% ethylacetate/hexane. 340 mg of the title
compound was recovered as a light greenish-white solid. M/e.sup.30 781
EXAMPLE 4
Preparation of the compound having the formula
##STR27##
0.128 grams of the compound having the formula
##STR28##
and 0.126 g of 2-carbophenoxyaminoaniline were mixed in approximately 3 ml
of N-methylpyrrolidinone to give an amber solution. After two days at room
temperature, the reaction mixture was added to 20 ml of saturated aqueous
sodium chloride solution. The green-gray precipitate that formed, was
filtered, washed with water and pressed partly dry before being dissolved
in 30 ml methylene chloride. Sodium sulfate was added to the methylene
chloride solution and after a brief drying period, the solution was
filtered. The green filtrate was concentrated to about 20 ml and applied
to a medium pressure silical gel column preconditioned with methylene
chloride. The column was eluted with methylene chloride and 60 mgs of the
following compound was recovered as a colorless oil.
##STR29##
60 mgs of the colorless oil obtained above was dissolved in 5 ml of
methylene chloride and 24 mgs of o-chloranil was added giving a dark
purple solution. After 10 minutes, TLC indicated that oxidation was
complete. The reaction solution was applied to a gravity silica column
preconditioned with 80:20 hexane/ethylacetate. The column was eluted with
80:20 hexane/ethylacetate and 20 mg of the title compound was recovered as
a white solid. M/e.sup.+ 671
The aniline used in Example 4 above was prepared according to the procedure
described in L. Raiford, E. Conrad and W. Coppock, J. Org. Chem. 7, pp.
346-53 (1942).
Compound 4A employed as the starting material in Example 4 was prepared
from the commercially available lactone, Compound (i), as follows:
##STR30##
A solution of 30 g of Compound (i) in 500 ml of dry tetrahydrofuran was
added dropwise to a slurry of 37.9 g. of lithium aluminum hydride in 500
ml of tetrahydrofuran under a nitrogen atmosphere with rapid mechanical
stirring during 40 minutes. The resulting mixture was refluxed for 40
minutes. After cooling to room temperature, an aliquot was examined by
silica gel TLC which showed the reaction to be complete. The excess
lithium aluminum hydride was destroyed by the dropwise addition of 100 ml
of ethyl acetate to the reaction mixture at about 0.degree. C. followed by
9.6 ml of water, 9.6 ml of 15% sodium hydroxide and finally 28.8 ml of
water. The reaction mixture was filtered through Celite to yield an
orange-yellow filtrate and the solvent removed under reduced pressure. The
residue was crystallized from 150 ml of ethanol (absolute) to give 14.6 g
of the following compound as orange crystals.
##STR31##
14.6 g of Compound (ii) was added to a saturated solution of hydrogen
bromide in 75 ml of methanesulfonic acid under a nitrogen atmosphere at
room temperature and stirred overnight. The reaction mixture was poured
into 1,000 ml of water and the blue-gray precipitate collected by
filtration. The pasty solids were dissolved in about 350 ml of methylene
chloride and washed once with 200 ml of saturated sodium bicarbonate in
water before drying the solution over sodium sulfate. The solution was
filtered and the filtrate treated with 15 g of silica gel, filtered again
and the solvent removed under reduced pressure to give 19.15 g of an
orange solid. The solid was triturated with 100 ml of ether and filtered
to yield 15.3 g of Compound 4A as a pale orange solid.
EXAMPLE 5
Preparation of the compound having the formula
##STR32##
To 5.0 g of the compound having the formula
##STR33##
was added 40 ml of phosphorus oxychloride and the resulting solution was
stirred at 70.degree. C. in an oil bath for 6 hours and then allowed to
stand overnight. The excess phosphorus oxychloride was removed by
distillation and the residue treated with 75 ml of toluene. After removing
the toluene, the residue was dissolved i | | |
