Note: Descriptions are shown in the official language in which they were submitted.
1~37~
--1--
This invention relates to furopyridinones and
furopyazinones useful as color formers in pressure-sensitive
carbonless duplicating systems and thermal marking systems,
to processes for the preparation thereof and to pressure-
sensitive duplicating systems and thermal marking systemscontaining the same.
Several classes of organic compounds of widely
diverse structural types are known to be useful as color
formers for carbonless duplicating systems. Among the more
widely recognized classes are phenothiazines, for example,
benzoyl leuco methylene blue; fluorans, for example, 2'-
anilino-6'-diethylaminofluoran; phthalides, for example,
crystal violet lactone, and various other types of color
formers currently employed in commercially acceptable carbon-
less duplicating systems. Typical of the many such systemstaught in the prior art are those described in U.S. Patents
2,712,507, 2,800,457 and 3,041,289. Many of the color
formers in the prior art, however, suffer one or more dis-
advantages such as low tinctorial strength, poor light
stability, low resistance to sublimation and low solubility
in common organic solvents.
U.S. Patent 3,775,424 and Belgian Patent 412,406
disclose furopyridinones and furopyrazinones for pressure-
sensitive record material and Belgian Patent 862,217 discloses
a series of phthalides useful as color formers in pressure-
sensitive carbonless duplicating systems, thermal marking
systems and hectographic or spirit-reproducing copying
systems.
The present invention relates to a series of
'~
1~l37~7~
7-(and 5-)(2-R3-4-NR4R5-phenyl) or (1-R6-2-R7-3-indolyl)-7-
~and 5-)[(Yl-Y2-phenyl)(Y3-Y4-phenyl)amino]furo[3,4-b]-
pyridine-5(7~)-[and 7(5H)-]ones, 3-(and 1-)(2-R3-4-NR4R5-
phenyl) or (l-R6-2-R7-3-indolyl)-3-(and 1-)[(Yl-Y2-phenyl)-
(Y3-Y4-phenyl)amino]furo[3,4-c]pyridine-1(3H)-[and 3(1H)-]-
d 7 (2-R -4-NR4R5-phenyl) or (1 R6 7
7-[~Yl-Y2-phenyl)~Y3-Y4-phenyl)amino]furo[3,4-b]pyrazine-
5~7H)ones which are useful as color formers in pressure-
sensitive carbonless duplicating systems and thermal marking
systems. The compounds develop colored images of good to
excellent tinctorial strength; possess high resistance to
sublimation, enhanced solubility in common organic solvents
and have the particular advantage of excellent light stability.
More specifically, the compounds of the invention
have the Formula I:
,~
N~4
Y~
1 2 Formula I
wherein A is a divalent radical of the formula:
`~ N' ~ ~ or ~ ;
N / ~ ~ / ~
(a) (b) ~c) (d) (e)
Yl, Y2 ~ Y3 and Y4 are the same or different hydro-
gen, halo, lower alkoxy, alkyl having from 1 to 9 carbon
atoms, phenyl-lower-alkyl or NRlR2 where Rl is hydrogen or
lower alkyl and R2 is hydrogen, lower alkyl, lower alkanoyl,
phenylsulfonyl or lower-alkyl-substituted phenylsulfonyl;
Z is a monovalent radical of the formula:
~ ,1
9t77
--3--
R4R5N ~ R3 or ~ ~ R7
(f) ~g) 6
in which:
R3 is hydrogen, lower alkyl, lower alkoxy, halo
or di-lower-alkylamino;
R4 is lower alkyl;
R5 is lower alkyl or benzyl;
R6 is hydrogen or non-tertiary alkyl having from
1 to 18 carbon atoms; and
R7 is hydrogen, phenyl or non-tertiary lower alkyl.
Preferably A is ~a) or td) and Z is ~f) above. Preferred
compounds within the ambit of this particular embodiment are:
7-[4-(dimethylamino)phenyl]-7-(diphenylamino)furo-
[3,4-b]pyridine-5(7H)-one
5-[4-(dimethylamino)phenylJ-5-~diphenylamino)furo-
[3,4-b]pyridine-7(5H)-one
7-[4-(dimethylamino)phenyl]-7-[bis(4-octylphenyl)amino]-
furo[3,4-b]pyridine-5(7H)-one
5-[4-(dimethylamino~phenyl]-5-[bis(4-octylphenyl)amino]-
furo[3,4-b]pyridine-7(5H)-one
7-[4-(diethylamino)-2-methylphenyl]-7-[bis(4-octyl-
phenyl)amino]furo[3,4-b]pyridine-5(7H)-one
5-[4-(diethylamino)-2-methylphenyl]-5-[bis(4-octyl-
phenyl)amino]furo[3,4-b]pyridine-7(5H)-one
7-(1-ethyl-2-methyl-3-indolyl)-7-(diphenylamino)furo-
[3,4-b]pyridine-5(7H)-one
5-(1-ethyl-2-methyl-3-indolyl)-5-(diphenylamino)furo-
[3,4-b]pyridine-7(5H)-one
7-(1-ethyl-2-methyl-3-indolyl)-7-[bis(4-octylphenyl)-
amino]furo[3,4-b]pyridine-5(7H)-one and
5-(1-ethyl-2-methyl-3-indolyl)-5-[bis(4-octylphenyl)-
amino]furo[3,4-b]pyridine-7~5H)-one.
One can prepare the compounds of Formula I herein-
above by a process which comprises reacting a pyridine-
~l37~
carboxylic acid having Formula II:
~ O~H
~1
\C=O
~ Formula II
with a diarylamine having Formula III:
Yz ~ ~ Formula III
in the presence of an anhydride of an alkanoic acid having
from 2 to 5 carbon atoms where in Formulas II and III, A,
Z, Yl, Y2, Y3 and Y4 have the previously given meanings.
One can also produce the compounds of Formula I
by reacting a pyridinecarboxylic acid of Formula II with
thionyl chloride, phosphorus oxychloride, phosphorus tri-
chloride or phosphorus pentachloride followed by reaction
of the resulting product with a diarylamine of Formula III
in the presence of an organic base where in Formulas II and
III, A, Z, Yl, Y2, Y3 and Y4 have the previously given
meanings.
The invention also deals with a pressure-sensitive
carbonless duplicating system or thermal marking system
containing a color-forming substance comprising a compound
having Formula I as described above. A particular embodi-
ment resides in a pressure-sensitive transfer sheet adapted
for use with a receiving sheet having an electron accepting
layer comprising a support sheet coated on one side with a
layer of pressure-rupturable microcapsules, said micro-
capsules containing a liquid solution of a color-forming
substance comprising at least one compound having Formula I.
Another embodiment resides in a heat-responsive record
material comprising a support sheet coated on one side with
a layer containing a mixture comprising at least one color-
forming compound having Formula I and an acidic developer
arranged such that application of heat will produce a mark-
~3~7'~
forming reaction between the color-forming compound and
the acidic developer.
As used herein the term "halo" includes chloro,
fluoro, bromo and iodo. Chloro is the preferred halo sub-
stituent because of the relatively low cost and ease of prep-
aration of the required chloro-substituted intermediates and
because the other halogens offer no particular advantages
over chloro. However, the other above-named halo substi-
tuents are also satisfactory. The terms "lower-alkyl",
"lower-alkoxy" and "di-lower-alkylamino" denote saturated
acyclic groups having from 1 to 4 carbon atoms which may be
straight or branched as exemplified by methyl, ethyl,
propyl, isopropyl, butyl, sec-butyl, isobutyl, tert-butyl,
methoxy, ethoxy, propoxy, isopropoxy, butoxy, sec-butoxy,
isobutoxy, tert-butoxy, dimethylamino, diethylamino, ethyl-
methylamino, dipropylamino, dibutylamino, isobutylmethyl-
amino, di-tert-butylamino and the like.
The term "lower-alkanoyl" denotes saturated
acyclic acyl groups having from 1 to 5 carbon atoms which
may be straight or branched as exemplified by formyl,
acetyl, propionyl, butyryl, isobutyryl, valeryl, 2-methyl-
butyryl, isovaleryl, pivalyl and the like.
The term "phenyl-lower-alkyl" includes benzyl,
2-phenylethyl, 2-phenylpropyl, 3-phenylpropyl, l-phenyl-
butyl, 2,2-dimethyl-2-phenylethyl and the like. If desired,
the phenyl group may contain a lower alkyl or lower alkoxy
substituent.
As used herein, the term "alkyl having from 1 to
9 carbon atoms" denotes saturated monovalent straight or
branched chain aliphatic hydrocarbon radicals including
methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-
butyl, amyl, l-methylbutyl, 3-methylbutyl, hexyl, isohexyl,
heptyl, isoheptyl, octyl, isooctyl, 2-ethylhexyl, nonyl,
3-ethylheptyl and the like.
The term "non-tert-alkyl having from 1 to 18
carbon atoms" includes in addition to the above-named alkyl
groups having from 1 to 9 carbon atoms, excluding, of course,
1~37'~7~
any tertiary alkyl groups, saturated monovalent straight
or branched chain aliphatic hydrocarbon radicals such as
n-decyl, n-undecyl, n-tridecyl, n-dodecyl, n-tetradecyl,
n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, 1,3,5-
trimethylhexyl, 1,5-dimethyl-4-ethylhexyl, 5-methyl-2-butyl-
hexyl, 2-propylnonyl, 2-butyloctyl, 2-pentylnonyl, 1,2-di-
methyltetradecyl and the like.
Anhydrides of alkanoic acids of 2 to 5 carbon
atoms include acetic anhydride, propionic anhydride,
butyric anhydride, isobutyric anhydride, valeric anhydride,
isovaleric anhydride, ~-methylbutyric anhydride, pivalic
anhydride and the like.
Acetic anhydride is preferred because of its low
cost and high reactivity. However, the other above-named
anhydrides are also satisfactory.
In the usual practice of the first process describ-
ed above, one reacts approximately equimolar amounts of the
pyridinecarboxylic acid of Formula II and the diarylamine
of Formula IIIin the presence of an anhydride of an alkanoic
acid having from 2 to 5 carbon atoms such as acetic anhydride
with or without an inert diluent at a temperature of about
0C. to 100C. for approximately 10 minutes to 72 hours.
The reaction is usually carried out in the absenae of an
inert diluent at about 20-50C. for approximately 0.5 to 2
hours. The product thus obtained can be isolated by filtra-
tion if it is insoluble in the reaction medium or by dilu-
tion of the reaction medium with a miscible solvent in which
the product is insoluble such as a lower alkanol or low
molecular weight hydrocarbon, for example, isopropyl alcohol
or hexane, or a mixture of these in order to effect precipi-
tation of the product. Alternatively, the reaction mixture
can be poured into aqueous base such as dilute ammonium
hydroxide, sodium hydroxide, sodium carbonate or sodium bi-
carbonate and the product extracted with an organic solvent
such as benzene or toluene followed by evaporation of the
organic solvent leaving the product as a residue. The product
once isolated, can be purified by conventional means such as
1~3 1~9c7~7
trituration or recrystallization from a suitable solvent.
In the above reaction the diarylamine of Formula
III serves as a basic catalyst. However, if desired an
additional organic base such as pyridine, collidine, tri-
lower-alkylamines, urea and the like can be employed.
Ordinarily pyridine and urea are preferred.
In the usual practice of the second process de-
scribed above, a compound of Formula I can be prepared in
two steps which comprise, first, reacting a pyridine
carboxylic acid of Formula II with an excess of an inorganic
acid chloride such as thionyl chloride, phosphorus oxy-
chloride, phosphorus trichloride or phosphorus pentachloride
with or without an inert diluent such as benzene, toluene,
chloroform, 1,2-dichloroethane or N,N-dimethylformamide at
20-80C. for about 0.5 to 2 hours, followed by a reaction
~`3 ~r the resulting product which, while not having been isolat-
ed, is presumed to be a chloride having Formula IV:
1 Formula IV
in which A and Z have the previously given meanings, with a
diarylamine of Formula III hereinabove in an inert solvent
in the presence of an organic base such as pyridine, collid-
ine, tri-lower-alkylamines or urea at a temperature in the
range of 0-80C. for about 1 to 48 hours. The product can
be isolated and purified in conventional fashion.
The pyridinecarboxylic acids and pyrazinecarboxylic
acids of Formula II hereinabove which are required as start-
ing materials in the preparation of the final products of
Formula I are generally known, for example, as disclosed in
U.S. Patents 3,936,564 and 3,775,424 and Japanese Patent
30 Publications 73/8727, 73/3205 and 73/8729. Those pyridine-
carboxylic acids and pyrazinecarboxylic acids which are
novel can be prepared in accordance with the procedures de-
scribed for the preparation of the known compounds, i.e., by
1~379t7r,)
reacting an anhydride having Formula V:
`~
A ¦l O
` _~. /
~ Formula V
with an appropriate aniline of Formula VI or an indole of
Formula VII:
\R7
NR4R5 6 Formula VII
Formula VI
wherein A, R3, R4, R5, R6 and R7 in the above formulas have
the previously given meanings, in the presence of a Lewis
acid, for example, aluminum chloride or zinc chloride, and
with a diluent such as benzene, chlorobenzene or o-dichloro-
benzene at a temperature of about 0-100C. The reaction is
conveniently carried out in benzene in the presence of
aluminum chloride at about 0-25C. The more reactive indoles
~Formula VII) can be reacted with the anhydrides (Formula V)
in the absence of a Lewis acid by simply heating the react-
ants together in an inert solvent at about 80-150C.
It will, of course, be appreciated that reaction
of the inherently unsymmetrical anhydrides of Formula V
wherein A is:
~ or
'~ ~
with an aniline of Formula VI or an indole of Formula VII
can produce isomers or a mixture of isomers of Z-CO-pyridine-
carboxylic acids (Formula II). For example, reaction of 2,3-
pyridinedicarboxylic anhydride ~Formula Va hereinbelow) with
an aniline or an indole of Formula VI or VII, respectively,
(Z-~ hereinbelow) can produce either a 2-(Z-CO)-3-pyridine-
113~ 7!7
carboxylic acid (Formula Ila~ or a 3-(Z-CO)-2-pyridine-
carboxylic acid ~Formula IIb) or a mix~ure of these. It
will, of course, be appreciated that the ratio of isomers
obtained will depend on various reaction conditions such as
temperature, solvent, catalyst and the relative solubility
of the isomers in the reaction medium. Ordinarily, when
carried out as described herein the reaction produces a
mixture of isomers with the 2-~Z-CO)-3-pyridinecarboxylic
acid (Formula IIa) predominating in the isolated product.
If desired, the mixture of isomeric Z-CO-pyridinecarboxylic
acids can be separated by conventional means such as selec-
tive precipitation at different pH, fractional crystalliza-
tion or chromatography and each of the individual isomers
IIa and IIb can then be reacted with an appropriate diaryl-
amine of Formula III to produce a furo-[3,4-b]pyridine-5(7H)-
one of Formula Ia and a furo-[3,4-b]pyridine-7(5H)-one of
Formula Ib, respectively. It is generally preferred however,
to simply react the isolated mixture of isomeric Z-CO-
pyridinecarboxylic acids of Formulas IIa and IIb with a di-
arylamine to produce an isomer mixture of furopyridinonesof Formulas Ia and Ib which can be separated by conventional
means if desired. However, since both isomers are useful as
color formers it is economically advantageous to simply use
the isolated mixture thereof in the practice of this invention.
~ ~ 2~ ~ 23 Y ~ ~ ~ y3
~ Z-H = ~ ~ = Y2 Y4
Va IIa Z IIb >
4+ ~4
1~3~9t77
--10--
In general, it has been found that the reaction of
2,3-pyridinedicarboxylic anhydride with an indole of Formula
VII in the manner described herein produces a mixture of
isomers of Formulas IIa and IIb ~Z is ~ ~
R7
in which isomer IIa predominates in the isolated product by
a factor greater than about 7. Moreover, it has been further
observed that the more abundant isomer (i.e. IIa) is also the
more reactive. ~ccordingly, subsequent reaction of the
isomeric mixture of IIa and IIb with a diarylamine of Formula
III produces almost exclusively furo[3,4-b]-pyridine-5(7H)-
one (Formula Ia) with isomer Ib being observed only in trace
amounts.
The reaction of 2,3-pyridinedicarboxylic anhydride
with an aniline of Formula VI in accordance with the pro-
cedures described herein also produces a mixture of isomersof Formulas IIa and IIb ~Z is ,~ ) and although
I
R4R5N ~ ~ ~ R3
isomer IIa again predominates in the isolated product,
significant amounts of isomer IIb are also obtained. Thus,
although isomer IIa is more reactive, a sufficient concen-
tration of the less reactive IIb is present in the mixture
to afford upon reaction with a diarylamine of Formula III a
mixture of isomeric furo[3,4-b~pyridinones of Formulas Ia
and Ib in which isomer Ia is predominant and isomer Ib is
present in minor, but significant amounts.
In like fashion, reaction of 3,4-pyridinedicarb-
oxylic anhydride (Formula Vb hereinbelow) with an aniline of
Formula VI or an indole of Formula VII (Z-H hereinbelow)
produces a mixture of 3-(Z-CO)-4-pyridinecarboxylic acid
(Formula IIc) and 4-(Z-CO)-3-pyridinecarboxylic acid
~Formula IId). The mixture is in turn reacted with a di-
arylamine of Formula III to produce an isomeric mixture of
1~l3~7!7
furo[3,4-c]pyridine-1(3H)-one (Formula Ic) and furo[3,4-c]-
pyridine-3(lH~-one (Formula Id).
p
~02H N~ 12H Y13
Vb IIc IId
4 + ~ _ ~ 4
Ic 1 2 i 2 Id
The diarylamines of Formula III which are also
required as starting materials in the processes of the in-
vention, belong to a well-known class of compounds and are
either commercially available or readily obtained by con-
ventional procedures well known in the art.
The novel compounds of Formula I hereinabove are
essentially colorless in the depicted formO When contacted
with an acidic medium, for example, silica gel, or one of
the types ordinarily employed in pressure-sensitive carbon-
less duplicating systems such as silton clay or phenolic
resins, the compounds of Formula I develop a yellow to black
colored image of good to excellent tinctorial strength and
possessing resistance to sublimation, xerographic copiability
and especially excellent light stabilityO The compounds
are thus highly suitable for use as colorless precursors,
that is, color-forming substances in pressure-sensitive
carbonless duplicating systems. Compounds which produce a
yellow to red color can be used as toners in admixture with
other color formers to produce images of a neutral shade
7~
-12-
which desirably are readily copiable by xerographic means.
The compounds of Formula I wherein one or more Yl, Y2, Y3
and Y4 are alkyl of 1 to 9 carbon atoms have excellent
solubility in common and inexpensive organic solvents, such
as odorless mineral spirits, kerosene, vegetable oils and
the like thereby avoiding the need for more expensive and
specialized solvents such as polyhalogenated or alkylated
biphenyls which have ordinarily been used to prepare micro-
encapsulated solutions of the color formers of the prior art.
The compounds of this invention may be incorporat-
ed in any of the commercially accepted systems known in the
carbonless duplicating art. A typical technique for such
application is as follows: solutions containing one or more
colorless precursor compounds of Formula I optionally in
admixture with other color formers in suitable solvents are
microencapsulated by well-known procedures, for example, as
described in U.S. Patent 3,649,649. The microcapsules are
coated on the reverse side of a transfer sheet with the aid
of a suitable binder and the coated transfer sheet is then
assembled in a manifold with the microcapsule-coated side
in contact with a receiving sheet coated with an electronic
accepting substance, for example, silton clay or a phenolic
resin. Application of pressure to the manifold such as
that exerted by a stylus, typewriter or other form of writ-
ing or printing causes the capsules on the reverse side torupture. The solution of the color former released from the
ruptured microcapsules flows to the receiving sheet and on
contact with the acidic medium thereon forms a yellow to
black image of good tinctorial strength and of superior light
stability. It is, of course, obvious that variants of this
mode of application can be utilized For example, the
receiving sheet in a manifold can alternatively be coated
with the subject compounds and the acidic developing agent
can be contained in microcapsules applied on the reverse
side of the top sheet in the manifold; or the receiving
sheet can be coated with a mixture containing both the acidic
developing agent and the microencapsulated color former.
1~7~7~
-13-
It has also been found that when the compounds
of Formula I are intimately mixed with an acidic developer
of the type generally employed in thermal papers such as
described in U.S. Patent 3,539,375, that is, papers which
produce a colored image when contacted with a heated stylus
or heated type, for example bisphenolA,heating of the mix-
ture produces a colored image of varying shades from yellow
to purple depending on the particular compound of the in-
vention employed. The ability of the compounds of Formula
I to form a deep color when heated in admixture with an
acidic developer such as bisphenol A makes them useful in
thermal paper marking systems either where an original or
duplicate copy is prepared by contacting the thermal paper
with a heated stylus or heated type in any of the methods
generally known in the art.
The molecular structure of the compounds of this
invention were assigned on the basis of the modes of
synthesis, elemental analyqis and study of their infrared,
nuclear magnetic resonance and mass spectra. The identity
and relative abundance of individual isomers in mixtures
of Z-CO-pyridinecarboxylic acids and furopyridinones were
determined on the basis of thin layer chromatography and
nuclear magnetic resonance spectroscopy using the shift re-
agent tris(dipivalomethanato)europium ~III) [Eu(DPM)3].
The following examples will further illustrate the
invention without, however, limiting it thereto.
EXAMPLE 1
A. To a mixture containing 10 g. of 2,3-pyridinedi-
carboxylic anhydride and 26 g. of N,N-diethyl-m-phenetidine
30 in 100 ml. of benzene was added 27 g. of aluminum chloride.
After stirring at about 40C. for 20 hours the reaction mix-
ture was filtered and the solid obtained was added to 800
ml. of ice-water. The resulting precipitate was collected,
washed with water and then dissolved in 600 ml. of 10%
aqueous sodium hydroxide. After filtering to remove a
small amount of insoluble material, the basic aqueous solu-
tion was acidified with dilute hydrochloric acid to pH 6.
1~37~
The resulting precipitate was collected, washed with water
and dried to give 13.4 g. of product. The filtrate was set
aside for further work-up as described in part B hereinbelow.
The 13.4 g. of solid material was again dissolved in
aqueous base. The resulting solution was filtered and the
filtrate adjusted to pH 6 with dilute hydrochloric acid.
The pale yellow solid which precipitated was collected,
washed with water and dried. The dried material was then
slurried in a mixture of 100 ml. of toluene and 10 ml. of
ethanol and the pale yellow solid was collected and dried
to give 2.6 g. of 3-[4-(diethylamino)-2-ethoxybenzoyl]-2-
pyridinecarboxylic acid, m.p. 264-270C. (dec.).
B. The filtrate which had been set aside was further
acidified to pH 2. The resulting light yellow precipitate
was collected, washed with water and dried to give 6.0 g. of
product. Recrystallization from ethanol-toluene afforded
4.0 g. of 2-[4-(diethylamino)-2-ethoxybenzoyl]-3-pyridine-
carboxylic acid, m.p. 209-210C.
C. A mixture containing 1.7 g. of 2-[4-(diethylamino)-
2-ethoxybenzoyl]-3-pyridinecarboxylic acid, 1.0 g. of di-
phenylamine, 0.5 g. of urea and 20 ml. of acetic anhydride
was stirred 20 hours at room temperature. Almost immediately
after the reactants had been combined, the mixture became
deep red in color indicating a rapid reaction. The reaction
mixture was poured into 300 ml. of toluene and 200 ml. of 5%
aqueous ammonium hydroxide. The toluene layer was separated,
washed successively with water and saturated aqueous sodium
chloride and then passed through a short column of silica
gel. The desired product was eluted from the silica gel
column with acetone. Evaporation of the acetone under
vacuum and crystallization of the residue from 2-propanol-
hexane afforded 1.7 g. of 7-[4-(diethylamino)-2-ethoxy-
phenyl]-7-~diphenylamino)furo[3,4 b]pyridine-5(7H)-one as
a light tan solid, m.p. 183.5-185C. This product produced
a red image on acid clay and phenolic resin.
D. Following a procedure similar to that described in
part C above, but employing 2.5 g. of 3-[4-(diethylamino)-2-
~;37~77
ethoxybenzoyl]-2-pyridinecarboxylic acid, 1.5 g. of di-
phenylamine, 0.5 g. of urea and 30 ml. of acetic anhydride
and allowing the reaction mixture to stir at room tempera-
ture for 2 days (the lack of a color change in the reaction
mixture after 5 hours indicated a slow reaction), there was
obtained 0.2 g. of 5-[4-(diethylamino)-2-ethoxyphenyl]-5-
(diphenylamino)furo[3,4-b]pyridine-7(5H)-one as a brown,
gummy material. This product produced a red image on
acidic clay and phenolic resin.
EXAMPLE 2
Following a procedure similar to that described in
Example lC hereinabove, but employing 1.7 g. of 2-[4-(di-
ethylamino)-2-ethoxybenzoyl]-3-pyridinecarboxylic acid,
1.1 g. of 3-chloro-N-phenylaniline, 0.5 g. of urea and 20
ml. of acetic anhydride, there was obtained 1.0 g. of 7-[(3-
chlorophenyl)phenylamino]-7-[4-~diethylamino)-2-ethoxy-
phenyl]furo[3,4-b]pyridine-5(7H)-one as a light tan solid,
m.p. 130-131C. This product produced a red image on
acidic clay and phenolic resin.
EXAMPLE 3
A mixture containing 2.0 g. of an isomer mixture
comprising 3-[4-(diethylamino)-2-methylbenzoyl]-2-pyridine-
carboxylic acid and 2-[4-(diethylamino)-2-methylbenzoyl]-3-
pyridinecarboxylic acid, 0.81 g. of 4,4'-bis(dimethylamino)-
diphenylamine, 6 ml. of acetic anhydride and 0.5 ml. of
pyridine was stirred 1 hour at room temperature and then
poured into 200 ml. of 5% aqueous ammonium hydroxide and
100 ml. of toluene. The toluene layer was separated, washed
with water and saturated aqueous sodium chloride and
evaporated to dryness under vacuum. The residue was slurried
in a minimum amount of acetone to give 0.5 g. of an isomer
mixture comprising 7-[4-(diethylamino)-2-methylphenyl]-7-
{bis[4-(dimethylamino)phenyl]amino}furo[3,4-b]pyridine-5(7H)-
one and 5-[4-(diethylamino)-2-methylphenyl]-5-{bis[4-(di-
methylamino)phenyl]amino}furo[3,4-b]pyridine-7(5H)-one, as
a light green solid, m.p. 184-186C. A chloroform solution
of the product contacted with acidic clay or phenolic resin
1~3~77
-16-
developed a black image.
EXAMPLE 4
A. A mixture containing 3~2 g. of an isomer mixture
comprising 2-[4-~diethylamino)-2 methylbenzoyl]-3-pyridine-
carboxylic acid and 3-[4-(diethylamino)-2-methylbenzoyl]-2-
pyridinecarboxylic acid, 2.05 g. of 4,4'-dioctyldiphenyl-
amine, 6 ml. of acetic anhydride and 1.1 ml. of pyridine
was stirred 45 minutes at room temperature. After diluting
the reaction mixture with 6 ml. of 2-propanol and 3 ml. of
hexane, the product was collected, washed with 2-propanol
and dried to give 1.5 g. of an isomer mixture comprising
7-[4-~diethylamino)-2-methylphenyl]-7-[bis-(4-octylphenyl)-
amino]furo[3,4-b]pyridine-5~7H)-one and 5-[4-(diethylamino)-
2-methylphenyl]-5-[bis~4-octylphenyl)amino]furo[3,4-b]-
pyridine-7~5H)-one as a light purple solid, m.p. 194-195C.
(dec.).
The filtrate was poured into 5% aqueous ammonium
hydroxide and the product was extracted with toluene. The
organic extracts were washed with water and saturated
aqueous sodium chloride and evaporated to dryness under
vacuum. Crystallization of the residue from 2-propanol
afforded 1.0 g. of additional product as a white solid. A
toluene solution of the product contacted with acidic clay
or phenolic resin developed a reddish-purple image.
B. To a mixture containing 1.4 g. of an isomer mix-
ture comprising 2-[4-~diethylamino)-2-methylbenzoyl]-3-
pyridinecarboxylic acid and 3-[4-(diethylamino)-2-methyl-
benzoyl]-2-pyridinecarboxylic acid, 1.0 ml. of thionyl
chloride and 60 ml. of N,N-dimethylformamide was added a
solution containing 1.84 g. of 4,4'-dioctyldiphenylamine
and 0.5 ml. of pyridine in 40 ml. of N,N-dimethylformamide
at room temperature. After stirring for one hour, the re-
action mixture was poured into 5% aqueous ammonium hydroxide.
The precipitate was collected, washed with water and air-
dried. The solid was then slurried in a mixture of 30 ml.of hexane and 10 ml. of 2-propanol and filtered to give
1.03 g. of product essentially identical to the product of
~l3747~
-17-
part A above.
C. A mixture containing 3.13 g. of an isomer mixture
comprising 2-[4-(diethylamino)-2-methylbenzoyl-3-pyridine-
carboxylic acid and 3-[4-(diethylamino~-2-methylbenzoyl]-2-
pyridinecarboxylic acid, 3.94 g. of 4,4'-dioctyldiphenyl-
amine, 6 ml. of acetic anhydride, 6 ml. of acetic acid and
0.75 g. of urea was stirred 2 hours at room temperature,
then poured into 5% aqueous ammonium hydroxide and extracted
with toluene. The organic extract was washed with water and
saturated aqueous sodium chloride and evaporated to dryness.
The residue was analyzed by thin layer chromatography and
infrared spectroscopy and shown to contain the desired
product identical to the product of part A above.
D. The reaction of part C above was carried out in
the absence of urea. The reaction mixture was poured into
5% aqueous ammonium hydroxide and extracted with toluene.
The toluene extract was washed with water, saturated aqueous
sodium chloride and evaporated to dryness. The residue was
analyzed by thin layer chromatography and infrared spectro-
scopy and shown to contain the desired product identical tothe product of part A above.
EXAMPLE 5
Following a procedure similar to that described in
Example 4A but employing 1.6 g. of an isomer mixture compris-
ing 2-[4-~diethylamino)-2-methylbenzoyl]-3-pyridinecarboxylic
acid 3-[4-(diethylamino)-2-methylbenzoyl]-2-pyridinecarboxylic
acid, 0.6 g. of 4-isopropoxy-N-phenylaniline, 0.5 ml. of
pyridine and 6 ml. of acetic anhydride there was obtained
0.7 g. of an isomer mixture comprising 7-[4-tdiethylamino)-
2-methylphenyl]-7-[4-isopropoxyphenyl)phenylamino]furo[3,4-b]-
pyridine-5(7H)-one and 5-[4-(diethylamino)-2-methylphenyl]-
5-[~4-isopropoxyphenyl)-phenylamino]furo[3,4-b]pyridine-7(5H)-
one as a white solid, m.p. 180-181C. A toluene solution of
the product contacted with acidic clay or phenolic resin
developed a reddish-purple image.
EXAMPLE 6
Following a procedure similar to that described in
7'7
Example 4A but employing 1.55 g~ of an isomer mixture com-
prising 2-[4-(diethylamino)benzoyl]-3-pyridinecarboxylic
acid and 3-[4-(diethylamino)benzoyl]-2-pyridinecarboxylic
acid, 1.2 g. of 4-isopropoxy-N-phenylaniline, 0.5 ml. of
pyridine and 6 ml. of acetic anhydride there was obtained
0.7 g. of an isomer mixture comprising 7-[4-tdiethylamino)-
phenyl]-7-[~4-isopropoxyphenyl)phenylamino]furo[3,4-b]-
pyridine-5(7H)-one and 5-[4-(diethylamino)phenyl]-5-[~4-iso-
propoxyphenyl)phenylamino]furo[3,4-b]pyridine]-7(5H)-one
as white solid, m.p. 173-175C. A toluene solution of the
product contacted with acidic clay or phenolic resin develop-
ed an orange image.
EXAMPLE 7
Following a procedure similar to that described in
Example 3 but employing 1.55 g. of an isomer mixture compris-
ing 2-[4-(diethylamino)benzoyl]-3-pyridinecarboxylic acid
and 3-[4-(diethylamino)benzoyl]-2-pyridinecarboxylic acid,
1.33 g. of 4,4'-bis-~dimethylamino)diphenylamine, 0.5 ml. of
pyridine and 6 ml. of acetic anhydride there was obtained
0.83 g. of an isomer mixture comprising 7-[4-(diethylamino)-
phenyl]-7~bis[4-(dimethylamino)phenyl]amino}furo[3,4-b]-
pyridine-5(7H)-one and 5-[4-diethylamino)phenyl]-5{bis[4-
(dimethylamino)phenyl]amino}furo[3,4-b]-7(5H)-one as a
light gray-brown solid, m.p~ 187C. (dec.). A toluene solu-
tion of the product contacted with acidic clay or phenolicresin developed a dark-brown image.
EXAMPLE 8
A mixture containing O . 2 g. of an isomer mixture
comprising 2-[4-(diethylamino)benzoyl]-3-pyridinecarboxylic
acid and 3-[4-~diethylamino)benzoyl]-2-pyridinecarboxylic
acid, 0.15 g. of diphenylamine and 5 ml. of acetic anhydride
was stirred 3 hours at room temperature. The reaction mix-
ture was poured into 100 ml. of toluene and 100 ml. of 5%
aqueous ammonium hydroxide~ The toluene layer was separated
washed successively with water and saturated a~ueous sodium
chloride and evaporated to dryness under vacuum. Crystal-
lization of the residue from hexane afforded 0.1 g. of an
1~3~7~
--19--
isomer mixture comprising 7-[4-(diethylamino)phenyl]-7-(di-
phenylamino)furo[3,4-b]pyridine-5(7H)-one and 5-[4-(diethyl-
amino)phenyl]-5-~diphenylamino)furo[3,4-b]pyridine-7(5H)-one
as a tan solid, m.p. 168-169C. This product produced a
deep orange image on acidic clay and phenolic resin.
EXAMPLE 9
A mixture containing 2.7 g. of an isomer mixture
comprising 2-[4-(dimethylamino)benzoyl]-3-pyridinecarboxylic
acid and 3-[4-(dimethylamino)benzoyl]-2-pyridinecarboxylic
acid and 25 ml. of acetic anhydride was heated to 50C.
After a solution formed, 1.7 g. of diphenylamine was added.
The mixture was stirred 2.5 hours at 25C., 50C. for 1.5
hours and then cooled to 5C. The resulting solid was
filtered and washed with isopropanol to give 1.3 g. of an
isomer mixture comprising 7-[4-(dimethylamino)phenyl]-7-~di-
phenylamino)furo[3,4-b]pyridine-5(7H)-one and 5-[4-(dimeth-
ylamino)phenyl]-5-(diphenylamino)furo[3,4-b]pyridine-7(5H)-
one as a very light orange solid, m.p. 175-179C. A toluene
solution of the product contacted with acidic clay or
phenolic resin developed an orange image.
EXAMPLE 10
Following a procedure similar to that described in
Example 9 but employing 2.7 g. of an isomer mixture compris-
ing 2-[4-(dimethylamino)benzoyl]-3-pyridinecarboxylic acid
and 3-[4-(dimethylamino)benzoyl]-2-pyridinecarboxylic acid,
4.0 g. of 4,4'-dioctyldiphenylamine and 25 ml. of acetic
anhydride there was obtained 2.7 g. of an isomer mixture com-
prising 7-[4-(dimethylamino)phenyl]-7-[bis(4-octylphenyl)-
amino]furo~3,4-b]pyridine-5~7H)-one and 5-[4-(dimethylamino)-
30 phenyl]-5-[bis(4-octylphenyl)amino]furo[3,4-b]pyridine-7(5H)-
one as a light peach solid, m.p. 203-208C. A toluene solu-
tion of the product contacted with acidic clay or phenolic
resin developed an orange image.
EXAMPLE 11
Following a procedure similar to that described in
Example 3 but employing 1.6 g. of an isomer mixture compris-
ing 3-[4-(diethylamino)-2-methylbenzoyl]-4-pyridinecarboxylic
7~
-2t)-
acid and 4-[4-(diethylamino)-2-methylbenzoyl]-3-pyridine-
carboxylic acid, 1.3 g. of 4,4'-bis(dimethylamino)diphenyl-
amine and 6 ml. of acetic anhydride there was obtained 1.5
g. of 3-[4-(diethylamino)-2-methylphenyl]-3{bis[4-(dimethyl-
amino)phenyl]amino}furo[3,4-c]pyridine-1(3H)-one and 1-[4-
(dimethylamino)-2-methylphenyl]-l{bis[4-(dimethylamino)-
phenyl]amino}furo[3,4-c]pyridine-3(lH)-one as a semi-solid.
A toluene solution of the product contacted with acidic clay
or phenolic resin developed a black image.
EXAMPLE 12
Following a procedure similar to that described in
Example 3 but employing 1.6 g. of an isomer mixture compris-
ing 3-[4-(diethylamino)-2-methylbenzoyl]-4-pyridinecarboxylic
acid and 4-[4-(diethylamino)-2-methylbenzoyl]-3-pyridine-
carboxylic acid, 0.9 g. of diphenylamine and 6 ml. of aceticanhydride there was obtained an isomer mixture comprising
3-[4-(diethylamino)-2-methylphenyl]-3-(diphenylamino)furo-
[3,4-c]pyridine-1(3H)-one and 1-[4-(diethylamino)-2-methyl-
phenyl]-l-(diphenylamino)furo[3,4-c]pyridine-3(1H)-one. A
toluene solution of the product contacted with acidic clay
or phenolic resin developed a red-grape image.
EXAMPLE 13
Following a procedure similar to that described in
Example 3 but employing 1.55 g. of an isomer mixture compris-
ing 3-[4-(diethylamino)benzoyl]-4-pyridinecarboxylic acid and
4-[4-(diethylamino)benzoyl]-3-pyridinecarboxylic acid, 1.3
g. of 4,4'-bis-(dimethylamino)diphenylamine, 0.5 ml. of
pyridine and 6 ml. of acetic anhydride there was obtained
1.5 g. of an isomer mixture comprising 3-[4-(diethylamino)-
phenyl]-3{bis[4-(dimethylamino)phenyl]amino}furo[3,4-c]-
pyridine-1(3H)-one and 1-[4-(dimethylamino)phenyl]-l{bis[4-
~dimethylamino)phenyl]amino}furo[3,4-c]pyridine-3(lH)-one as
a viscous oil. A toluene solution of the product contacted
with acidic clay or phenolic resin developed a brown image.
EXAMPLE 14
Following a procedure similar to that described in
Example 3 but employing 1.55 g. of an isomer mixture compris-
ing 3-[4-(diethylamino)benzoyl]-4-pyridinecarboxylic acid and
1~37gt77
-2~-
4-[4-(diethylamino~benzoyl]-3-pyridinecarboxylic acid,
1.2 g. of 4-acetamido-N-phenylaniline, 0.5 ml. of pyridine
and 6 ml. of acetlc anhydride there was obtained 1.5 g. of
an isomer mixture comprising 3-[4-(diethylamino~phenyl]-3-
[~4-acetamidophenyl~phenylamino]furo[3,4-c]pyridine-1(3H~-
one and 1-[4-(diethylamino)phenyl]-1-[(4-acetamidophenyl~-
phenylamino]furo[3,4-c]pyridine-3~1H)-one as a red-brown
solid, m.p. 102-116C. A toluene solution of the product
contacted with acidic clay or phenolic resin developed an
orange-red image.
EXAMPLE 15
3.0 Grams of an isomer mixture comprising 3-[4-
(diethylamino)benzoyl]-4-pyridinecarboxylic acid and 4-[4-
(diethylamino)benzoyl]-3-pyridinecarboxylic acid in 30 ml.
of acetic anhydride was heated to 40C. After a solution
formed, 4.0 g. of 4,4'-dioctyldiphenylamine was added, the
mixture was stirred 7 hours, and then allowed to stand
another 40 hours. The resulting solution was poured into
100 ml. of ice-water containing 76 ml. of concentrated
ammonium hydroxide. The product was extracted into 75 ml.
of toluene which was separated, dried over anhydrous calcium
chloride and evaporated leaving an oil. Crystallization
from hexane yielded ~.8 g. of an isomer mixture comprising
3-[4-(diethylamino)phenyl]-3-~bis(4 octylphenyl)amino]furo-
25 [3,4-c]pyridine-1(3H)-one and 1-[4-(diethylamino)phenyl]-
l-[bis(4-octylphenyl)amino]furo[3,4-c]pyridine-3(lH)-one as
a tan solid, m.p. 114-117C. A toluene solution of the
product contacted with acidic clay or phenolic resin de-
veloped an orange image.
EXAMPLE 16
Following a procedure similar to that described in
Example 3 but employing 3.0 g. of an isomer mixture compris-
ing 3-[4-~diethylamino)benzoyl]-4-pyridinecarboxylic acid
and 4-[4-(diethylamino)benzoyl]-3-pyridinecarboxylic acid,
1.7 g. of diphenylamine and 30 ml. of acetic anhydride there
was obtained 1.4 g. of an isomer mixture comprising 3-[4-~di-
ethylamino)phenyl]-3-(diphenylamino)furo[3,4-c]pyridine-1(3H)-
one and l-[4-(diethylamino)phenyl]-1-(diphenylamino)furo-
7~
[3,4-c]pyridine-3(1H)-one as a light orange solid, m.p. 135-
141C. A toluene solution of the product contacted with
acidic clay or phenolic resin developed an orange image.
EXAMPLE 17
2.6 Grams of an isomer mixture comprising 3-[4-
(diethylamino)-2-methylbenzoyl]-4-pyridinecarboxylic acid
and 4-[4-(diethylamino)-2-methylbenzoyl]-3-pyridinecarboxylic
acid in 30 ml. of acetic anhydride was heated to 40C. and
then 4.0 g. of 4,4'-dioctyldiphenylamine was added. The
mixture was stirred for 3 hours at room temperature then
poured into 100 ml. of ice-water and 76 ml. of concentrated
ammonium hydroxide to yield 5.7 g. of an isomer mixture com-
prising 3-[4-(diethylamino)-2-methylphenyl]-3-[bis(4-octyl-
phenyl)amino]furo[3,4-c]pyridine-1~3H)-one and 1-[4-(di-
ethylamino)-2-methylphenyl]-1-[bis(4-octylphenyl)amino]furo-
[3,4-c]pyridine-3(lH)-one as a red solid, m.p. 58-105C.
A toluene solution of the product contacted with acidic clay
or phenolic resin developed a violet image.
EXAMPLE 18
Following a procedure similar to that described in
Example 3 but employing 1.63 g. of 3-[4-(diethylamino)-2-
methylbenzoyl]-2-pyrazinecarboxylic acid, 1.3 g. of-4,4'-bis-
(dimethylamino)diphenylamine, 0.5 ml. of pyridine and 6 ml.
of acetic anhydride there was obtained 0.9 g. of 7-[4-(di-
ethylamino)-2-methylphenyl]-7{bis[4-~dimethylamino)phenyl]-
amino}furo[3,4-c]pyrazine-5~7H)-one as a light orange solid,
m.p. 193.5-195C. (dec.). A toluene solution of the product
contacted with acidic clay or phenolic resin developed a
black image.
EXAMPLE 19
Following a procedure similar to that described in
Example 3 but employing 1.6 g. of 3-[4-(diethylamino)-2-
methylbenzoyl]-2-pyrazinecarboxylic acid, 0.9 g. of diphenyl-
amine, 0.5 ml. of pyridine and 6 ml. of acetic anhydride
35 there was obtained 0.1 g. of 7-[4-(diethylamino)-2-methyl-
phenyl]-7-(diphenylamino)furo[3,4-c]pyrazine-5(7H)-one, m.p.
189.5-191C. (dec.). A toluene solution of the product con-
-23-
tacted with acidic clay or phenolic resin developed a red-
grape image.
EXAMPLE 20
Following a procedure similar to that described
in Example 3 but employing 0.43 g. of 3-[4-(diethylamino)-
benzoyl]-2-pyrazinecarboxylic acid, 0.34 g. of 4,4'-bis-
(dimethylamino)diphenylamine, 0.5 ml. of pyridine and 6 ml.
of acetic anhydride there was obtained 0.59 g. of 7-[4-(di-
ethylamino)phenyl]-7{bis-[4-(dimethylamino)phenyl]amino}furo-
[3,4-b]pyrazine-5(7H)-one, m.p. 61-74C. A toluene solution
of the product contacted with acidic clay or phenolic resin
developed a red-brown image.
EXAMPLE 21
Following a procedure similar to that described in
Example 3 but employing 0.5 g. of 3-[4-~diethylamino)benz-
oyl]-2-pyrazinecarboxylic acid, 0.38 g. of 4-isopropoxy-N-
phenylaniline, 0.5 ml. of pyridine and 6 ml. of acetic an-
hydride there was obtained 0.6 g. of 7-[4-(diethylamino)-
phenyl]-7-[(4-isopropoxyphenyl)phenylamino]furo[3,4-b]-
pyrazine-5(7H)-one, m.p. 75-82C. A toluene solution of
the product contacted with acidic clay or phenolic resin
developed an orange-brown image.
EXAMPLE 22
A mixture containing 0.7 g. of 3-[4-(dimethyl-
amino)benzoyl]-2-pyrazinecarboxylic acid, 1.0 g. of 4,4'-di-
octyldiphenylamine and 7 ml. of acetic anhydride was stirred
and gently heated in a warm water bath for one hour. The
product, 7-[4-(dimethylamino)phenyl]-7-[bis(4-octylphenyl)-
amino]furo[3,4-b]pyrazine-5(7H)-one was isolated by column
chromatography as a rust-colored solid, m.p. 158-168C. A
toluene solution of the product contacted with acidic clay
or phenolic resin developed a reddish-brown image.
EXAMPLE 23
A mixture of 0.1 g. of 3-[4-(diethylamino)benzoyl]-
2-pyrazinecarboxylic acid, 0.1 g. of diphenylamine and 2 ml.
of acetic anhydride was warmed for several hours and then
allowed to stand for three days. The product, 7-[4-(diethyl-
~1.3~
-24-
amino)phenyl]-7-(diphenylamino)fuxo[3,4-b]pyrazine-5(7H)-
one was isolated by column chromatography as a light orange
solid, m.p. 140-142.6C. A toluene solution of this product
contacted with acidic clay or phenolic resin developed a red
image.
EXAMPLE 24
A mixture containing 0.15 g. of 3-[4-(diethylamino)-
benzoyl]-2-pyrazinecarboxylic acid, 0.18 g. of 4,4'-dioctyl-
diphenylamine and 3 ml. of acetic anhydride was gently heat-
ed for 5 hours and then allowed to stand overnight. Theproduct, 7-[4-(diethylamino)phenyl]-7-[bis(4-octylphenyl)-
amino]furo[3,4-b]pyrazine-5(7H)-one was isolated by column
chromatography followed by crystallization from hexane to
give a peach solid, m.p. 180-181C. A toluene solution of
this product contacted with acidic clay or phenolic resin
developed a red image.
EXAMPLE 25
A mixture containing 3.1 g. of 3-[4-(diethylamino)-
2-methylbenzoyl]-2-pyrazinecarboxylic acid, 3.1 g. of 4,4'-
dioctyldiphenylamine and 25 ml. of acetic anhydride wasstirred in a warm water bath for 3 hours. The reaction mix-
ture was poured into water and the resulting solid was
collected and recrystallized from hexane to give 7-[4-(di-
ethylamino)-2-methylphenyl]-7-[bis(4-octylphenyl)amino]furo-
[3,4-b]pyrazine-5(7H)-one as a light tan solid, m.p. 180-
187C. A toluene solution of this product contacted with
acidic clay or phenolic resin developed a violet image.
EXAMPLE 26
Following a procedure similar to that described in
Example 3 but employing 4.5 g. of an isomer mixture compris-
ing 2-[(1-ethyl-2-methyl-3-indolyl)carbonyl]-3-pyridinecarb-
oxylic acid and 3-[(1-ethyl-2-methyl-3-indolyl)carbonyl]-2-
pyridinecarboxylic acid, 3.6 g. of 4-ethoxy-N-phenylaniline,
1 ml. of pyridine and 8 ml. of acetic anhydride there was
obtained 5.5 g. of 7-(1-ethyl-2-methyl-3-indolyl)-7-[(4-
ethoxyphenyl)phenylamino]furo[3,4-b]pyridine-5(7H)-one as a
tan solid, m.p. 122-129C. ~dec.). A toluene solution of
7~7?7
-25-
the product contacted with acidic clay or phenolic resin
developed an orange image.
EXAMPLE 27
Following a procedure similar to that described in
Example 3 but employing 1.6 g. of an isomer mixture compris-
ing 2-~1-ethyl-2-methyl-3-indolyl)carbonyl]-3-pyridine-
carboxylic acid and 3-[(1-ethyl-2-methyl-3-indolyl)carbonyl]-
2-pyridinecarboxylic acid, 2.0 g. of 4,4'-dioctyldiphenyl-
amine, 0.5 ml. of pyridine and 6 ml. of acetic anhydride
there was obtained 0.9 g. of 7-(1-ethyl-2-methyl-3-indolyl)-
7-[bis(4-octylphenyl)amino]furo[3,4~b]pyridine-5(7H)-one as
a light tan solid, m.p. 187C. (dec.). A toluene solution
of the product contacted with acidic clay or phenolic resin
developed an orange image.
EXAMPLE 28
Following a procedure similar to that described in
Example 3 but employing 1.6 g. of an isomer mixture compris-
ing 2-[(1-ethyl-2-methyl-3-indolyl)carbonyl]-3-pyridine-
carboxylic acid, and 3-[(1-ethyl-2-methyl-3-indolyl)carbonyl]-
2-pyridinecarboxylic acid, 1.1 g. of 4-(dimethylamino)-N-
phenylaniline, 0.5 ml. of pyridine and 6 ml. of acetic
anhydride there was obtained 1.3 g. of 7-(1-ethyl-2-methyl-
3-indolyl)-7~[4-(dimethylamino)phenyl]phenylamino~furo~3,4-b]-
pyridine-5(7H)-one as a gray soiid, m.p. 191-192C. (dec.).
A chloroform solution of the product contacted with acidic
clay or phenolic resin developed a brown image.
EXAMPLE 29
Following a procedure ~imilar to that described in
Example 3 but employing 1.6 g. of an isomer mixture compris-
ing 2-[(1-ethyl-2-methyl-3-indolyl)carbonyl]-3-pyridine-
carboxylic acid and 3-[(1-ethyl-2-methyl-3-indolyl)carbonyl]-
2-pyridinecarboxylic acid, 1.3 g. of 4,4'-bis-(dimethylamino)-
diphenylamine, 0.5 ml. of pyridine and 6 ml. of acetic
anhydride there was obtained 0.35 g. of 7-(1-ethyl-2-methyl-
3-indolyl)-7-~bis[4-(dimethylamino)phenyl]amino~furo[3,4-b]-
pyridine-5(7H)-one as a white solid, m.p. 205-206C. ~dec.).
A chloroform solution of the product contacted with acidic
1~l.3~77
-26-
clay or phenolic resin developed a brown image.
EXAMPLE 30
Following a procedure similar to that described in
Example 3 but employing 1.6 g. of an isomer mixture compris-
ing 2-[~1-ethyl-2-methyl-3-indolyl)carbonyl]-3-pyridinecarb-
oxylic acid and 3-[(1-ethyl-2-methyl-3-indolyl)carbonyl]-2-
pyridinecarboxylic acid, 0.95 g. of N-phenyl-m-toluidine,
0.5 ml. of pyridine and 6 ml. of acetic anhydride there was
obtained 7-(1-ethyl-2-methyl-3-indolyl)-7-(m-tolylphenyl-
amino)furo[3,4-b]pyridine-5(7H)-one as a yellow solid, m.p.
178-190C. (dec.). A toluene solution of the product con-
tacted with acidic clay or phenolic resin developed an
orange image.
EXAMPLE 31
A mixture containing 4.5 g. of an isomer mixture
comprising 2-[(1-ethyl-2-methyl-3-indolyl)carbonyl]-3-
pyridinecarboxylic acid and 3-[(1-ethyl-2-methyl-3-indolyl)-
carbonyl]-2-pyridinecarboxylic acid, 2.5 g. of diphenylamine
and 30 ml. of acetic anhydride was stirred 6.5 hours, then
treated with one ml. of pyridine and allowed to stand over-
night. The reaction mixture was poured into 750 ml. of
water and the resulting solid product was purified by column
chromatography affording 7-(1-ethyl-2-methyl-3-indolyl)-7-
(diphenylamino)furo~3,4-b]pyridine-5(7H)-one as a light
orange solid, m.p. 132.5-136C. A toluene solution of the
product contacted with acidic clay or phenolic resin develop-
ed an orange image.
EXAMPLE 32
Following a procedure similar to that described in
Example 3 but employing 1.6 g. of an isomer mixture compris-
ing 3-[(1-ethyl-2-methyl-3-indolyl)carbonyl]-4-pyridine-
carboxylic acid and 4-[(1-ethyl-2-methyl-3-indolyl)carbonyl]-
3-pyridinecarboxylic acid, 0.9 g. of diphenylamine, 0.5 ml.
of pyridine and 6 ml. of acetic anhydride there was obtain-
ed 1-(1-e~hyl-2-methyl-3-indolyl)-1-~diphenylamino)furo[3,4-
c]pyridine-3~1~)-one as a viscous oil. A toluene solution of
the product contacted with acidic clay or phenolic resin
~.3~7'~
-27-
developed an orange image.
EXAMPLE 3 3
Following a procedure similar to that described in
Example 3 but employing 3.1 g. of 3-[~1-ethyl-2-methyl-3-
indolyl)carbonyl]-2-pyrazinecarboxylic acid, 2.2 g. of
4-ethoxy-N-phenylaniline, 2 ml. of pyridine and 10 ml. of
acetic anhydride there was obtained 1.1 g. of 7-(1-ethyl-2-
methyl-3-indolyl)-7-[~4-ethoxyphenyl)phenylamino]furo~3,4-b]-
pyrazine-5(7H)-one as a light brown solid, m.p. 120-135C.
(dec.)O A toluene solution of the product contacted with
acidic clay or phenolic resin developed a reddish-orange
image.
EXAMPLE 34
Following a procedure similar to that described in
Example 3 but employing 0.8 g. of 3-[(1-ethyl-2-methyl-3-
indolyl)carbonyl]-2-pyrazinecarboxylic acid, 1.0 g. of 4,4'-
dioctyldiphenylamine, 0.25 ml. of pyridine and 3 ml. of
acetic anhydride there was obtained 7-(1-ethyl-2-methyl-3-
indolyl)-7-[bis(4-octylphenyl)amino]furo[3,4-b]pyrazine-5(7H)-
one as a semi-solid. A toluene solution of the product con-
tacted with acidic clay or phenolic resin developed an
orange image.
EXAMPLE 35
A mixture containing 4 g. of 3-[(1-ethyl-2-methyl-
3--1ndolyl)carbonyl]-2-pyrazinecarboxylic acid, 1.7 g. of di-
phenylamine and 15 ml. of acetic anhydride was stirred 1
hour at room temperature and then 30 minutes with gentle
warming. The product, 7-(1-ethyl-2-methyl-3-indolyl)-7-tdi-
phenylamino)furo[3,4-b]pyrazine-5(7H)-one was isolated by
column chromatography as a red solid, m.p. 98-100C. A
toluene solution of this product contacted with acidic clay
or phenolic resin developed an orange image.
It is contemplated that by following procedures
similar to those described in the foregoing examples but
employing the appropriate Z-CO-pyridinecarboxylic acids of
Formula II and appropriately substituted diarylamines of
Formula III there will be obtained the compounds of Formula I,
Examples 36-65, presented in the following Table.
79~
--28-- c~ -
I o C~ C~
~ ~ o o
C~ ~ ~ ~ o I -
I ~ o
~_~ W N W E E
N E 0 o
C~ ~ ~ Z ~ C~ Z
~Y ~ ~ X ~
O ~)
~ X ~ X ~ X ~ 0
c I X ~ X ~ X
In
_~ ~ X X X ~ X X X X ~
Il ~ ~ ~ m
W ~C~ ~ ~0 ~
~: ~ R
:Y; I I I I ~ ~: C ) R I R
3:
r~ W
X~ Xc~
,o
I ~ _ _ _ _ _ _ _ _ ,~ ~,
X ~ o ~1 C~l ~ ~ ~ C!~
~3~9!7'7
--29--
2~)
* C~ * Ln
~, 2 ~, 2
~ ~ ,~
r~ r,J N ra N O a-
2~ ~ V~ ~, cn ~
~ y 0 y z ~ y z m y y y
~ i J ~r) J X ~ ~> ~ X X:~ ~ 2 (~ U~ X ~1
C~ ~ .
2 2 y O
r~ ~ X 2 ,2, X 2 X X XX ,2 N ,2 ~ ~ ~ :i' Il)
1 2'1 2~ 2-1 2~ 2'
N ~ :~ ,2 ~ C X ~ i X ~ ul X X C~
--1 N O
¦ 2 X ~ ~ 2 2 X ~ 2 X N ~2 ,2 C ~ 2 ,2
~J 2U~ m
$'
~ ~o
~tD I I I I X X X Rl al x I I I Y~
a~
¦ X ~'7 X X C~ ~'7 C)
Ir~ N ,2 (D N ~ ~2 ~V ¦ 2
xa~ ~
C~
U~
$ ~ ~ ~
0~. N ~ N ,2, ,2 2 1 1 I >~ O
h a~
o Z
N N ~
8 2'J' ~ a
z c~
N ~ N C.~ ~, 'rl
O ~ ~ Xo
2 2 ~ 2 a~ O'ri
C~ N C~ 2 ~ al ~ ~q m I I 1 8 ~
~ a o ~I N ~i' L~ O a> O ~ *0 C~
1~l371'~7~
--30--
In
J c~
C~
Z X
~ ~ SO ~`
~ ~ ~ 1~ N
I
~r~ 1 3 X
U~
:::
P~ ~
".~ ~ C`l
P~ I I C~ C~
~I I C~
1~
X ~ ~ ~ U~
D (D
~37~77
--31--
EXAMPLE 6 6
A solution containing 1.46 g. of the color former
of Example 28 in 60 ml. of isopropylbiphenyl and a solution
containing 5 g. sf carboxymethylcellulose in 200 ml. of water
were mixed and emulsified by rapid stirring. The desired
particle size (5 microns~ was checked by microscope. To the
emulsion was added a solution containing 15 g. of pigskin
gelatin in 120 ml. of water. The pH was adjusted to 6.5 with
10% aqueous sodium hydroxide with rapid stirring, and follow-
ing the gradual addition of 670 ml. of water at 50C. the pHwas adjusted to 4.5 with 10% aqueous acetic acid with con-
tinued rapid stirring. After 5 minutes the mixture was
cooled to 15C., treated with 10 g. of 25% aqueous glutar-
aldehyde and rapidly stirred for 15 minutes. The resulting
microcapsule dispersion was stirred more slowly overnight,
diluted with water to 1120 g. and coated on white typewriter
paper sheets (0.0015 in. film thickness). The sheets were
air dried. Duplicate typewritten images were made on
receiving sheets coated with either phenolic resin or acidic
clay. The color former of Example 28 produced a brown image
on both types of receiving sheets.
EXAMPLE 67
A polyvinyl alcohol dispersion of the color former
of Example 28 was prepared by shaking 1 hour on a paint
shaker a mixture containing 2.0 g. of the color former, 3.7
g. of water, 8.6 g. of 10% a~ueous polyvinyl alcohol and 10
g. of zirconium grinding beads. A polyvinyl alcohol dis-
persion of bisphenol A was prepared by shaking a mixture con-
taining 9.8 g. of bisphenol A, 18.2 g. of water, 42 g. of 10%
aqueous polyvinyl alcohol and 70 ml. of zirconium grinding
beads. The coating mixture was made by combining and
thoroughly mixing 2.1 g. of the polyvinyl alcohol dispersion
of the color former with 47.9 g. of the polyvinyl alcohol
dispersion of bisphenol A. The coating mixture was applied
(at thicknesses of 0.003 and 0.0015 inches) to white mimeo
paper sheets and the sheets were dried at room temperature.
Contacting the coated sheets with a heated stylus at a
temperature between 110C. and 150C. produced a purple image.
