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Description  |
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The present invention refers to a new class of cyanine dyes and their use
as spectral sensitizers in direct positive photographic materials.
The new class of cyanine dyes of the present invention comprises at least
one heterocyclic nucleus comprising a 5 or 6-membered ring joined by a
methine linkage to a second heterocyclic nucleus or a para-amino phenyl
group, the first of said heterocyclic nuclei being a nucleus of the
benzoxazole or benzothiazole series having at least 2-halogen atoms as
substituents in the phenyl group thereof, joined to the methine linkage in
the 2 -position of said nuclei; the second nucleus is a nucleus suitable
to complete a cyanine dye. The second nucleus conveniently contains a
heterocyclic nitrogen atom or para-amino phenyl group and the methine
chain consists of a polyenic chain, containing an equal number of
alternating single and double bonds, one terminal carbon atom of which is
the carbon atom in the 2-position of a nucleus of the benzoxazole or
benzothiazole series, characterized in that it has at least 2-halogen
atoms as substituents in the phenyl group, the other terminal carbon atom
of the chain being comprised by the second nitrogen containing
heterocyclic nucleus. Preferably, the second nucleus of these dyes is a
desensitizing nucleus (known in the prior art, for example, as in U.S.
Pat. No. 3,431,111, col. 1, line 60 -col. 2, line 6, and F. M. Hamer, "The
Cyanine Dyes and Related Compounds" pp. 728-729, Interscience Publishers,
1964).
In another embodiment, the present invention refers to merocyanine dyes
comprising two nuclei joined together by a methine chain containing an
equal number of alternating single and double bonds; the first of said
nuclei being a nucleus of the benzoxazole or benzothiazole series, having
at least 2 halogen atoms as substituents in the phenyl group, joined to
the methine chain through its carbon atom in the 2-position; and the other
nucleus being a nitrogen containing ketomethylenic nucleus, having
therefore a methylene group activated by a carbonyl group being comprised
in the cyclic ring.
In a further embodiment, the present invention relates to styryl dyes
comprising a nucleus derived from di-halogen-benzoxazoles, or
di-halogen-benzothiazoles, joined through a methine chain having an equal
number of alternating single and double bonds, one terminal atom of the
chain being the carbon atom in the 2-position of said di-halogenated
benzo-azole nuclei, the other terminal carbon atom being in the benzene
ring, substituted in the para-position with a dialkylamino group.
In still another embodiment, the present invention refers to dyes
containing 2 nuclei of the di-halogen substituted benzoxazole or
benzothiazole series joined together by a chain having an equal number of
alternating single and double bonds through the carbon atoms in the
2-position of the heterocyclic nucleus. The methine chain joining the two
nuclei preferably consists of 3 methine groups.
The new dyes according to the present invention derived from benzoxazoles
ane benzothiazoles having two halogen atoms as substituents in the phenyl
group, can be represented by the following general formulas:
##STR1##
wherein: Y is oxygen or sulfur;
n is a positive integer equal to 2,3,4;
m is 1 or 2;
n is 1 or 2;
q is a positive integer of from 1 to 3;
R and R.sub.1, equal or different, represent two halogen atoms, such as
chlorine, bromine, fluorine and iodine;
R.sub.2 is a hydrogen atom or an alkyl group having from 1 to 4 carbon
atoms;
R.sub.3 represents an alkyl, cycloalkyl or substituted alkyl group, such as
for instance methyl, ethyl, propyl, isopropyl, butyl, hexyl, cyclohexyl,
decyl, or dodecyl; an alkoxy-alkyl group, such as for instance .beta.
-methoxyethyl or .omega.-buthoxy-butyl; an hydroxy-alkyl group, such as
for instance .beta. -hydroxyethyl or .omega.-hydroxybutyl; a carboxy-alkyl
group, such as for instance carboxy-methyl, .beta. -carboxyethyl, .delta.
carboxypropyl, .omega. -carboxybutyl; a sulfoalkyl group, such as for
instance .beta. -sulfoethyl, .delta. -sulfopropyl, .delta.-sulfobutyl,
.omega. sulfobutyl, etc.; a alkoxy-carbonyl-alkyl group, such as for
instance .beta. -methoxycarbonyl-ethyl or .omega.-methoxy-carbonyl-butyl;
an alkenyl group, such as for instance alkyl, 1-propenyl, 2-butenyl, etc.;
an aryl group, such as for instance phenyl, tolyl, xilyl, chlorophenyl,
methoxyphenyl, naphthyl, etc.;
R.sub.4 represents a hydrogen atom or an alkyl group having from 1 to 3
carbon atoms, such as for instance methyl, ethyl, propyl;
R.sub.5 and R.sub.6, equal or different, each represent an alkyl group
contining containing 1 to 6 carbon atoms;
X- represents an acid anion, such as for instance chloride, bromide,
iodide, sulfamate, perchlorate, p-toluensulfonate, methyl-sulfate, etc.;
Z represents the non-metallic atoms required to complete a sensitizing or
desensitizing heterocyclic nucleus containing from 5 to 6 atoms in the
heterocyclic nucleus, which may also include more than a hetero-atom, such
as for instance oxygen, sulfur, selenium or nitrogen, for instance the
following nuclei:
a nucleus of the series of the thiazole, for instance thiazole,
4-methyl-5-phenyl-thiazole, 5-methyl-thiazole, 5-phenyl-thiazole,
4,5-dimethyl-thiazole, 4,5-diphenylthiazole, 4-(2-thienyl)-thiazole or
4-nitro-thiazole; of the benzothiazole (e.g. benzothiazole,
4-chlorobenzothiazole, 5-nitro-benzothiazole, 5-chloro-benzothiazole,
6-nitro-benzothiazole, 5,6-dinitro-benzothiazole, 6-chloro-benzothiazole,
7-chloro-benzothiazole, 4-methylbenzothiazole, 5-methyl-benzothiazole,
6-methyl-benzothiazole, 5-bromo-benzothiazole, 6-bromo-benzothiazole,
5-phenyl-benzothiazole, 6-phenyl-benzothiazole, 1-methoxybenzothiazole,
5-methoxy-benzothiazole, 6-methoxy-benzothiazole, 5-bromo-benzothiazole,
5-iodo-benzothiazole, 6-iodo-benzothiazole, 4-ethoxy-benzothiazole,
5-ethoxybenzothiazole, tetrahydro-benzothiazole,
5,6-dimethoxybenzothiazole, 5,6-dioxymethylene-benzothiazole,
5-hydroxybenzothiazole, 6-hydroxy-benzothiazole); of the naphthothiazole
(e.g. .alpha.-naphthothiazole, .beta.-naphthothiazole,
5-methoxy-.beta.-naphthothiazole, 5-ethoxy-.beta.-naphthothiazole,
8-methoxy-.alpha.-naphthothiazole, 7-methoxy-.alpha.-naphthothiazole); of
the naphthothiazoles having nitro-substituent; of the oxazole (e.g.
4-methyl-oxazole, 4-nitro-oxazole, 5-methyl-oxazole, 4-phenyl-oxazole,
4,5-diphenyl-oxazole, 4-ethyl-oxazole, 4,5-dimethyl-oxazole,
5-phenyl-oxazole); of the benzoxazole (e.g. benzoxazole,
5-chloro-benzoxazole, 5-nitro-benzoxazole, 5-methyl-benzoxazole,
5-phenylbenzoxazole, 6-nitro-benzoxazole, 6-methyl-benzoxazole,
5,6-dinitro-benzoxazole, 5,6-dimethyl-benzoxazole,
4,6-dimethyl-benzoxazole, 5-methoxy-benzoxazole, 5-ethoxybenzoxazole,
5-chloro-benzoxazole, 5-bromo-benzoxazole, 5-iodo-benzoxazole,
6-methoxy-benzoxazole, 5-hydroxybenzoxazole, 6-hydroxy-benzoxazole); of
the naphthoxazole (e.g. .alpha.-naphthoxazole, .beta.-naphthoxazole); of
the naphthoxazoles substituted with a nitro-group; of the selenazole (e.g.
selenazole, 4-methyl-selenazole, 4-phenyl-selenazole); of the
benzoselenazole (e.g. benzoselenazole, 4-nitrobenzoselenazole,
6-nitro-benzoselenazole, 5-chlorobenzoselenazole,
5-methoxy-benzoselenazole, 5-hydroxybenzoselenazole,
5-nitro-benzoselenazole, tetrahydrobenzoselenazole); of the
naphtho-selenazole (e.g. .alpha.-naphthoselenazole,
.beta.-naphtho-selenazole); of the naphtho-selenazoles substituted with a
nitro-group; of the thiazoline (e.g. thiazoline, 4-methyl-thiazoline,
4-nitro-thiazoline, etc.); of the pyridine (e.g. pyridine, 2-pyridine,
5-methyl-2-pyridine, 4-pyridine, 3-methyl-4-pyridine); pyridine
substituted with a nitro-group; of the quinoline (e.g. quinoline,
2-quinoline, 3-methyl-quinoline, 5-ethylquinoline, 6-chloro-quinoline,
8-chloro-quinoline, 6-methoxy-quinoline, 8-ethoxy-quinoline
8-hydroxy-quinoline); of the 4-quinoline (e.g. 6-methoxy-4-quinoline,
1-methoxy-4-quinoline, 7-methyl-4-quinoline, 8-chloro-4-quinoline); of the
1-isoquinoline (e.g. 3,4-dihydro-1-isoquinoline); 3-isoquinoline;
quinolines having a nitro-substituent; of the 1,1-dialkyl-indolenine (e.g.
1,1-dimethyl-5 or 6-cyano-indolenine, 1,1-dimethyl-5 or
6-nitro-indolenine, 1,1-dimethyl-5-chloro-indolenine); of the imidazole
(e.g. imidazole, 1-alkyl-imidazole, 1 -alkyl-4-phenyl-imidazole,
1-alkyl-4,5-dimethyl-imidazole); of the benzimidazole (e.g.
1-alkyl-benzimidazole, 1-aryl-5,6-dichloro-benzimidazoles); of the
naphthimidazole (e.g. 1-alkyl-.alpha.-naphthoimidazole,
1-aryl-.beta.-naphtho-imidazole,
1-alkyl-5-methoxy-.alpha.-naphtho-imidazole).
The nuclei, wherein Z represents the atoms required to make a
nitro-substituted heterocyclic nucleus, give densitizing dyes particularly
useful to make direct positive emulsions and materials using such
emulsions, according to the present invention. Particularly, the preferred
nuclei are selected from the groups formed by nitro-benzothiazoles (e.g.
5-nitro-benzothiazole, 6-nitrobenzothiazole,
5-chloro-6-nitro-benzothiazole); or from the groups formed by the
homologous derivatives obtained by substituting sulfur with oxygen or
selenium, or from the groups formed by imidazo[4,5-b]quinoxalines (e.g.
imidazo[4,5-b]quinoxaline, 1,3-dialkyl-imidazo[4,5-b]quinoxaline,
1,3-diethyl-imidazo[4,5-b]quinoxaline,
6-chloro-1,3-diethyl-imidazo[4,5-b]quinoxaline,
1,3-dialkenyl-imidazo[4,5-b]quinoxaline, 1,3-diallyl-imidazo
[4,5-b]quinoxaline, 6,7-dichloro-1,3-diallyl-imidazo [4,5-b]quinoxaline,
1,3-diaryl-imidazo[4,5-b]quinoxaline
1,3-diphenyl-imidazo[4,5-b]quinoxaline,
6-chloro-1,3-diphenyl-imidazo[4,5-b]quinoxaline); or from the groups
formed by 3H-pyrrolo[2,3-b]pyridine (e.g.
3,3-dialkyl-3H-pyrrolo[2,3b]pyridine, 3,3-diethyl or
3,3-dimethyl-3H-pyrrolo[2,3-b]pyridine); or from the groups formed by
3H-nitro-indoles (e.g. 3,3-dialkyl-3H-nitro-indole, 3,3-dimethyl or
3,3-diethyl-5-nitro-3H-indole); from the groups formed by
thiazole[4,5-b]quinoline or formed by nitro-quinoline (e.g.
5-nitro-quinoline, 6-nitroquinoline, etc.).
Q represents the non-metallic atoms required to complete a 5 to 6-membered
heterocyclic nucleus, such as for instance a 2-pyrazolin-5-one nucleus
(e.g. 3-methyl-1-phenyl-2-pyrazolin-5-one, 1-phenyl-2-pyrazolin-5-one,
1-(2-benzothiazolyl)-3-methyl-2-pyrazolin-5-one, etc.); an isoxazolone
nucleus (e.g. 3-phenyl-5(4H)-isoxazolone, 3-methyl-5(4H)-isoxazolone,
etc.); an oxindole nucleus (e.g. 1-alkyl-2,3-dihydro-2-oxindoles, etc.); a
2,4,6-triketohexahydro-pyrimidine nucleus (e.g. barbituric acid or
2-thio-barbituric acid and their 1-alkyl derivatives, such as for instance
1-methyl, 1-ethyl, 1-propyl, etc.; 1,3-dialkyl derivatives, such as for
instance 1,3-dimethyl, 1,3-diethyl, 1,3-dipropyl, etc.; 1,3-diaryl
derivatives, such as for instance 1,3 -diphenyl, 1,3-di(p-chlorophenyl),
etc.; 1-aryl derivatives, such as for instance 1-phenyl, 1
-p-chlorophenyl; 1-alkyl-3-aryl derivatives, such as for instance
1-ethyl-3-phenyl, 1-n-heptyl-3-phenyl, etc.); a
2-thio-2,4-thiazolidine-dione nucleus (rhodanine) (e.g. rhodanine
3-alkyl-rhodanine, such as for instance 3-methylrhodanine,
3-ethyl-rhodanine, 3-alkyl-rhodanine; 3-carboxy-alkyl-rhodanines, such as
for instance 3-.beta.-carboxy-ethyl-rhodanine, 3-carboxy-methyl-rhodanine,
etc.; 3-sulfo-alkyl-rhodanines, such as for instance
3-.beta.-sulfo-ethyl-rhodanine, 3-.delta.-sulfo-propyl-rhodanine, etc;
3-aryl-rhodanines, such as for instance 3-phenylrhodanine,
3-p-sulfo-phenyl-rhodanine, etc.); a 2-thio-2,4-oxazolidine-dione nucleus
(e.g. 3-ethyl-2-thio-2,4-oxazolidin-dione,
3-.beta.-sulfo-ethyl-2-thio-2,4-oxazolidinedione,
3-p-sulfo-phenyl-2-thio-2,4-oxazolidine-dione,
3-.delta.-sulfo-butyl-2-thio-2,4-oxazolidine-dione,
3-.delta.-carboxy-propyl-2-thio-2,4-oxazolidin-dione, etc.); a
thianaphthenone nucleus (e.g. 3-(2H)-thianaphthenone, etc.); a
2-thio-2,5-thiazolidine-dione nucleus (e.g.
2-thio-2,5-(3H,4H)-3-ethyl-thiazolidin-dione, etc.); a
2-4-thiazolidine-dione nucleus (e.g. 3-ethyl-2,4-thiazolidine-dione,
3-phenyl-2,4-thiazolidine-dione,
3-.alpha.-naphthyl-2,4-thiazolidine-dione, etc.); a thiazolidinone nucleus
(e.g. 4-thiazolidinone, 3-ethyl-4-thiazolidinone,
3-phenyl-4-thiazolidinone, 3-.alpha.-naphthyl-4-thiazolidinone, etc.); a
2-thiazolin-4-one nucleus (e.g. 2-ethyl-mercapto-2-thiazolin-4-one,
2-alkylphenylamino-2-thiazolin-4-one, 2-diphenylamino-2-thiazolin-4-one,
etc.); a 2-imino-4-oxazolidinone (i.e. pseudohydantoin) nucleus; a
2,4-imidazolidine-dione (hydantoin) nucleus (e.g. 2,4-imidazolidine-dione,
3-ethyl-2,4-imidazolidine-dione, 3-phenyl-2,4-imidazolidine-dione,
3-.alpha.-naphthyl-2,4-imidazolidine-dione,
1,3-diethyl-2,4-imidazolidine-dione,
1-ethyl-3-phenyl-2,4-imidazolidinedione,
1-ethyl-3-.alpha.-naphthyl-2,4-imidazolidine-dione,
1,3-diphenyl-2,4-imidazolidine-dione, etc.); a
2-thio-2,4-imidazolidine-dione (i.e. 2-thio-hydantoin) nucleus (e.g.
2-thio-2,4-imidazolidine-dione, 3-ethyl-2-thio-2,4-imidazolidine-dione,
3-.omega.-sulfobutyl-2-thio-2,4-imidazolidine-dione,
3-.beta.-carboxyethyl-2-thio-2,4-imidazolidine-dione,
3-phenyl-2-thio-2,4-imidazolidinedione,
3-.alpha.-naphthyl-2-thio-2,4-imidazolidine-dione,
1-ethyl-3-phenyl-2-thio-2,4-imidazolidine-dione,
1-ethyl-3-.alpha.-naphthyl-2-thio-2,4-imidazolidine-dione,
1,3-diphenyl-2-thio-2,4-imidazolidine-dione, etc.).
Except where already limited in the above descriptions of dependent groups,
such dependent groups as R.sub.3, X.sup.-, and the second nucleus
(heterocyclic or para-amino phenyl) do not substantially effect the
performance of the types by even extreme variation in size. The following
limitations are derived mainly from economic considerations in the
selection of size limit for dependent groups.
Group R.sub.3 is generally preferred to have no more than 18 carbon atoms,
more preferred to have no more than 12 carbon atoms and most preferred to
have no more than 4 carbon atoms. It is generally preferred to have no
more than 8 non-metallic heteroatoms and more preferably no more than 5
such heteroatoms.
The second nucleus is generally preferred to have no more than 50 carbon
atoms, more preferably no more than 30, and most preferably no more than
20 carbon atoms. It is generally preferred to have no more than 10
heteroatoms in the second nucleus, with no more than 5 heteroatoms in the
heterocyclic ring.
According to the present invention, the dyes represented by general
formulas [1], [2], [3], [4] can be conveniently prepared by using new
compounds of formula:
##STR2##
wherein: R, R.sub.1, R.sub.2, R.sub.3 and X.sup.- have the above mentioned
meanings.
The new compounds of formula [5] can be advantageously prepared by
cyclizaton of suitable intermediates according to whether Y is oxygen or
sulfur.
The symmetrical carbocyanines having general formula [1] can be
conveniently prepared by reacting 2 moles of a compound selected among
those represented by general formula [5] with 1 mole, or with 1 mole +
100% in excess, of ethyl-ortho-formate or diethoxymethylacetate to prepare
carbocyanines (n = 2) wherein R.sub.4 is hydrogen; with 1 mole, or with 1
mole + 100% excess, of triethylorthoacetate to prepare carbocyanines (n =
2) wherein R.sub.4 is a methyl group; with 1 mole, or with 1 mole + 100%
excess, of triethylorthopropionate to prepare carbocyanines (n = 2)
wherein R.sub.4 is an ethyl group; with trimethoxypropene or
acroleynaldehyde dianylhydrochloride to give dicarbocyanines (n = 3), etc.
To prepare the unsymmetrical cyanines of general formula [2], wherein n =
2, 3, 4, a compound selected among those represented by general formula
[5] is reacted with a compound selected among those represented by general
formula:
##STR3##
wherein: n, R.sub.3, Z and X.sup.- have the above mentioned meanings;
R.sub.7 is an aryl group (such as for instance phenyl, tolyl, etc.); and
R.sub.8 is an alkyl group having from 1 to 18 carbon atoms.
The reaction is carried out in an inert solvent in the presence of a basic
catalyst.
Particularly, the unsymmetrical cyanines represented by general formula
[3], wherein n=2, can be prepared by reacting a compound represented by
general formula [5] with a compound selected among those represented by
general formula:
##STR4##
wherein: R.sub.3, Z and m have the above-mentioned meanings.
The condensations are conveniently carried out in acetic acid or acetic
anhydride; the dye separated by cooling is purified by one or more
crystallizations from a suitable solvent.
Styryl dyes having general formula [3] can be prepared by heating a mixture
of a compound selected among those represented by general formula [5] with
a suitable N,N-di-substituted-p-amino-benzaldehyde or
N,M-di-substituted-p-amino-cinnamaldehyde, preferably in a suitable
solvent and in the presence of a basic catalyst.
The merocyanines represented by general formula [4] can be prepared by
reacting a compound of general formula [5] with a compound of general
formula:
##STR5##
wherein: R.sub.9 represents an aryl group (such as for instance phenyl,
tolyl, etc.);
R.sub.10 represents an alkyl group having from 1 to 12 carbon atoms. The
reactions are conveniently carried out in an inert solvent and in the
presence of a basic catalyst.
The following examples will better illustrate the present invention in its
different aspects, viz. preparation of intermediates, dyes as well as
their use in light-sensitive emulsions.
EXAMPLE 1
2-acetylamino-4,6-dibromo-phenol
##STR6##
A mixture of 89 g. of 2-nitro-4,6-dibromo-phenol, 270 ml. of methyl
alcohol, 50ml. of 30% NaOH aqueous solution and 2,400 ml. of demineralized
water was heated up to 50.degree.-55.degree. C., obtaining a yellow
solution. To this solution, 178 g. of Na.sub.2 S.sub.2 O.sub.3 were added
in small portions, by keeping the temperature at 50.degree. C. The
reaction mixture was then stirred for 30 minutes by keeping the
temperature at 65.degree. C. and finally for 30 minutes at room
temperature. By cooling, 44.2 g. of 2-amino-4,6-dibromo-phenol were
obtained, having a melting point equal to 89.degree.-92.degree. C.
44.2 g. of 2-amino-4,6-dibromo-phenol were processed with 85.5 ml. of
acetic anhydride keeping the temperature under 50.degree. C. By cooling,
the 2-acetylamino-4,6-dibromo-phenol separated; it was collected on a
filter and crystallized from ethyl alcohol. 30 g. of pure product were
obtained. M.P. = 175.degree.-176.degree. C.
Percent analysis: C% calculated 31.10, found 31.11.
H% calculated 2.28, found 2,29.
N% calculated 4.53, found 4.54.
EXAMPLE 2
2-methyl-5,7-dibromo-benzoxazole
##STR7##
A mixture of 40 g. of 2-acetylamino-4,6-dibromophenol and 1.5 g. of
anhydrous sodium acetate was heated at 180.degree. C. for some minutes,
obtaining a liquid slurry which was distilled under vacuum, by collection
the fraction passed from 150.degree. C. to 155.degree. C. at 1.6 mm. Hg.
The distilled oil by standing became a solid which was crystallized from
ligroin, obtaining 25 g. of 2-methyl-5,7-dibromo-benzoxazole. M.P. =
122.degree.-124.degree. C.
Percent analysis: C% calculated 33.02, found 33.14. H% calculated 1.73,
found 1.70. N% calculated 4.81, found 4.92.
EXAMPLE 3
2-acetylamino-5-methyl-4,6-dichloro-phenol
##STR8##
To a mixture of 68.4 g. of 2-amino-5-methyl-4,6-dichloro-phenol
hydrochloride and 96 ml. of N,N-diethylaniline in 750 ml. of acetone, 23.4
ml. of acetyl chloride were added slowly by keeping the temperature under
20.degree. C. At the end, the reaction mixture was heated to reflux for an
hour. After cooling, the solution was poured into water; the solid
product, thus obtained, was collected on a buckner, washed with water
until the washings were neutral and dried in a desicator at 50.degree. C.
The raw product obtained was purified by crystallization from ethyl
alcohol, yielding 44 g. of a pure product with M.P. =
175.degree.-176.5.degree. C.
EXAMPLE 4
2,6-dimethyl-5,7-dichloro-benzoxazole
##STR9##
A mixture of 79 g. of 2-acetylamino-5-methyl-4,6-di-chloro-phenol and 3.6
g. of anhydrous sodium acetate was heated at 180.degree. C. for some
minutes. The liquid obtained was distilled under vacuum, collecting the
fraction passed from 140.degree. C. to 145.degree. C. at 1.2 mm. Hg. The
distilled oil became a mass of crystals which was purified by
crystallization from ligroin. 36 g. of pure base were obtained. M.P. =
80.degree.-82.degree. C.
Percent analysis: C% calculated 50.05, found 50.02. H% calculated 3.27,
found 3.16. N% calculated 6.49, found 6.55.
EXAMPLE 5
2,3-dimethyl-5,7-dibromo-benzoxazole methyl-sulfate
##STR10##
A mixture of 2.9 g. of 2-methyl-5,7-dibromo-benzoxazole and 2.5 ml. of
dimethyl-sulfate were heated at 150.degree. C. for 5 minutes. By cooling,
a solid cake was obtained. It was then ground in a mortar by washing
repeatedly with ethyl ether. The product was employed without further
purification for the dye synthesis.
EXAMPLE 6
2-methyl-3-ethyl-5,7-dibromo-benzoxazole ethyl-sulfate
##STR11##
The compound was prepared as described in Example 5 using diethysulfate
instead of methylsulfate.
EXAMPLE 7
2,6-dimethyl-3-ethyl-5,7-dichloro-benzoxazole ethyl-sulfate
##STR12##
The compound was prepared as described in Example 5 using
2,6-dimethyl-5,7-dichloro-benzoxazole and diethylsulfate.
EXAMPLE 8
2,6-dimethyl-3-ethyl-5,7-dichloro-benzoxazole p-toluene sulfonate
##STR13##
A mixture of 2.1 g. of 2,6-dimethyl-5,7dichloro-benzoxazole and 2 g. of
ethyl-p-toluene-sulfonate was heated at 150.degree. C. for 30 minutes. By
cooling, a pick cake was obtained. It was ground in a mortar by washing
repeatedly with ethyl ether. The product, thus obtained, was dried and
used without further purification for the synthesis of dyes.
EXAMPLE 9
Anhydro-2,6-dimethyl-3-.gamma.-sulfo-propyl-5,7-dichloro-benzoxazole
hydroxide
##STR14##
A mixture of 4.32 g. of 2,6-dimethyl-5,7-dichloro-benzoxazole and 3.66 g.
of 1,3-propane-sulfone was heated at 150.degree. C. for 15 minutes. The
pick cake, obtained by cooling, was ground in a mortar by washing
repeatedly with ethyl ether. The hygroscopic solid, thus obtained, was
dried under vacuum and used immediately without any further purification
for the dye synthesis.
EXAMPLE 10
2-methyl-5,6-dichlorobenzothiazole
##STR15##
A mixture of 66 g. of 2,4,5-trichloro-1-nitrobenzene and 120 ml. of ethyl
alcohol was poured into a 750 ml. flask equipped with reflux condenser,
mechanical stirrer and dropping funnel and heated to reflux. Through the
funnel, a sodium disulfide aqueous solution, obtained by dissolving 72 g.
of Na.sub.2 S . H.sub.2 O and 9.6 g. of sulfur in 45 ml. of boiling water,
was dropped into. At the end, the reaction mixture was heated to reflux
under stirring for half an hour. By cooling, a gum separated which became
solid on standing overnight and by washing with hot water.
61.8 g. of 2,2'-dinitro-4,5-4',5'-tetrachlorodiphenyl-disulfide was
obtained and poured immediately into a 1,500 ml. keller equipped with
mechanical stirrer, thermometer and reflux condenser, containing 394 ml.
of acetic acid and mounted on a sand bath. To this mixture, heated up to
90.degree. C., 112 g. of Zn-powder was added in small portions. At the end
the heating was continued for two hours and a half, then 45 ml. of acetic
anhydride were added and the reflux heating continued for 2 hours. The hot
mixture was hot filtered on a buckner, washing the solid with hot acetic
acid and then cooled and made basic with ammonia. The gum obtained on
standing became solid. It was then ground in a mortar by washing with
ammonia aqueous solution and then air dried. The solid was distilled under
reduced pressure collecting the fraction from 190.degree. C. to
200.degree. C. at 2 mm. Hg. The distilled oil, on standing, became a mass
of white crystals which were purified by crystalization from ligroin. 20
g. of pure base were obtained, having a melting point equal to
165.degree.-170.degree. C.
Percent analysis: N% calculated 6.4, found 6.0.
EXAMPLE 11
3,3'-diethyl-5,7-5',7'-tetrabromo-oxacarbocyanine perchlorate
##STR16##
A mixture of 2.91 g. of 2-methyl-5,7-dibromobenzoxazole and 2.6 g. of
ethyl-p-toluene-sulfonate was heated to 140.degree. C. for 4 hours. The
pick cake obtained by cooling was ground in a mortar by washing repeatedly
with ethyl ether. The resulting solid was dissolved in 15 ml. of anhydrous
pyridine and 2.5 ml. of triethylorthoformiate and the solution was heated
to reflux for 15 minutes. By cooling, the dye separated as gum which was
dissolved in a minimum quantity of ethyl alcohol. An ammonium perchlorate
aqueous solution was added to the dye solution. By standing, the raw dye
separated; it was collected on a filter, washed and crystallized from
ethyl alcohol. 0.85 g. of pure dye were obtained having an M.P. =
283.degree.-6.degree. C. .lambda. max. = 495 nm. (ethyl alcohol).
EXAMPLE 12
3,3'-diethyl-5,7-5',7'-tetrabromo-oxacarbocyanine iodide
##STR17##
The dye was prepared as described in Example 11, using potassium iodide
instead of ammonium perchlorate. After crystallization from ethyl alcohol,
a pure dye was obtained, having a M.P. = 278.degree.-281.degree. C.
.lambda. max = 495 nm. (ethyl alcohol).
EXAMPLE 13
3,3'-dimethyl-5,7,5',7'-tetrabromo-9-ethyl-oxacarbocyanine perchlorate
##STR18##
A mixture of 4.17 g. of 2,3-dimethyl-5,7-dibromobenzoxazole methyl-sulfate
in 15 ml. of pyridine and 2.5 ml. of triethyl-ortho-propionate was heated
to reflux for an hour. After cooling, the reaction mixture was poured into
ethyl ether. The yellow gum separated, was washed with ethyl ether and
dissolved in a minimum quantity of hot ethyl alcohol. To this solution, an
ammonium perchlorate aqueous solution was added. The dye, separated by
cooling, was collected on a buckner, dried under vacuum and crystallized
from dimethylformamide, 0.1 g. of pure dye was obtained having a M.P. =
330.degree. C. .lambda. max. = 500 nm. (ethyl alcohol -
dimethylformamide).
EXAMPLE 14
3,3',9-triethyl-5,7-5',7'-tetrabromo-oxacarbocyanine perchlorate
##STR19##
The dye was prepared as reported in Example 12 using
triethylorthopropionate as condensing agent, instead of
triethylorthoformiate. The raw dye was purified by crystallization from
ethyl alcohol. M.P. = 281.degree.-4.degree. C. .lambda. max. = 499 nm.
(ethyl alcohol).
EXAMPLE 15
3-ethyl-3'-methyl-5,7-dibromo-5',6'-dimethyl-oxacarbocyanine iodide
##STR20##
A mixture of 4.17 g. of 2,3-dimethyl-5,7-dibromobenzoxazole methyl-sulfate
and 4.62 g. of 2- .omega.
-acetanilido-vinyl-3-ethyl-5,6-dimethyl-benzoxazole-iodide in 20 ml. of
anhydrous pyridine and 2 ml. of triethylamine, was heated to reflux for 20
minutes. The reaction solution was chilled into ethyl ether : the
separated dye was collected on a filter, dried and crystallized from ethyl
alcohol. 1.2 g. of pure dye were obtained. M.P. - 256.degree.- 258.degree.
C. .lambda. max. = 495 nm. (ethyl alcohol).
EXAMPLE 16
(3-methyl-5,7-dibromo-benzoxazole-2)-(3-ethyl-thiazolidine-2)-trimethine-cy
anine iodide
##STR21##
A mixture of 2.08 g. of 2,3-dimethyl-5,7-dibromobenzoxazole methyl sulfate
and 2.01 g. of 2-.omega.-acetanilido-vinyl-3-ethyl-thiazolidine iodide in
15 ml. of anhydrous pyridine and 1 ml. of triethylamine was heated to
reflux for 20 minutes. The raw dye, separated from the reaction mixture by
adding ethyl ether, was collected on a buckner and washed repeatedly with
ethyl ether. After crystallization from a mixture of ethyl alchol ethyl
ether, the pure dye was obtained having a M.P. = 165.degree.-173.degree.
C. .lambda. max. = 465 nm. (ethyl alcohol).
EXAMPLE 17
(3-methyl-5,7-dibromo-benzoxazole-2)-(3-ethyl-6-nitro-benzothiazole-2)-trim
ethinecyanine methyl sulfate
##STR22##
A mixture of 2.08 g. of 2,3-dimethyl-5,7-dibromobenzoxazole methylsulfate
and 1.25 g. of 2-formyl-methylene-3-ethyl-6-nitrobenzothiazoline in 30 ml.
of acetic anhydride, was heated to reflux for 6 minutes. After cooling,
the crude dye was collected on a buckner, washed with acetic anhydride
ethyl ether and ethyl alcohol and purified by repeatedly boiling with
acetic acid. 1.9 g. of pure dye were obtained having an M.P. =
297.degree.-299.5.degree. C. .lambda. max, = 539 nm. (ethyl
alcohol-dimethylformamide).
EXAMPLE 18
3,3' -diethyl-5,7-5', 7'-tetrachloro-6,6'-dimethyl-oxacarbocyanine ethyl
sulfate
##STR23##
A solution of 3.6 g. of 2,6-dimethyl-3-ethyl-5,7-di-chloro-benzoxazole
ethyl-sulfate in 20 ml. of anhydrous pyridine and 3 ml. of
triethyl-ortho-formiate was boiled for 6 minutes and after cooling poured
into ethyl ether. The crude dye was collected on a buckner, washed
repeatedly with ethyl ether and then boiled with ethyl alcohol. After
recrystallization, 1.0 g. of pure dye was obtained having an M.P. -
263.degree.-270.degree. C. .lambda. max. = 497 nm. (ethyl
alcohol-dimethylformamide).
EXAMPLE 19
Anhydro-3,3'-(.delta.-sulfo)-propyl-5,7-5',
7'-tetrachloro-6,6'-dimethyl-oxacarbocyanine hydroxide
##STR24##
A mixture of 3.38 g. of
anhydro-2,6-dimethyl-3-.delta.-sulfo-propyl-5,7-dichloro-benzoxazole-hydro
xide in 25 ml. of nitrobenzene and 5 ml. of triethylorthoformiate was
heated to reflux for 15 minutes. After cooling, the solution was poured
into ethyl ether and acetone, the crude dye was collected and boiled with
water. After crystallization from a 3:1 mixture of ethyl alcohol and
dimethylformamide, 0.8 g. of pure dye was obtained. M.P. -
299.degree.-303.degree. C. .lambda. max. = 499 nm. (ethyl
alcohol-dimethylformamide).
EXAMPLE 20
(3-ethyl-5,7-dichloro-6-methyl-benzoxazole-2)-(3-ethyl-6-nitro-benzothiazol
e-2)-trimethinecyanine ethyl-sulfate
##STR25##
A mixture of 3.6 g. of 2,6-dimethyl-3-ethyl-5,7-di-chloro-benzoxazole ethyl
sulfate and 2.5 g. of 2-formylmethylene-3-ethyl-6-nitro-benzothiazoline in
15 ml. of acetic anhydride and 7 ml. of acetic acid, was boiled for 6
minutes. After cooling, the reaction mixture was poured into ethyl ether:
the dye separated as gum. It was then boiled with absolute ethyl alcohol
until a dark-green powder was obtained.
The crude dye was purified by boiling it repeatedly with absolute ethyl
alcohol and the pure dye collected on a buckner and washed with ethyl
ether. 1.7 g. of pure dye dye were obtained. M.P. =
194.degree.-197.degree. C. .lambda. max. = 541 nm. (ethyl
alcohol-dimethylformamide).
EXAMPLE 21
3-ethyl-5-[(3-ethyl-5,7-dichloro-6-methyl-benzoxazoline-2-ylidene)-ethylide
ne]-rhodanine
##STR26##
4.44 g. of 2,6-dimethyl-3-ethyl-5,7-dichlorobenzoxazole ethyl sulfate and
2.16 g. of 3-ethyl-5-.omega.-acetanilido-methylene-rhodanine were
dissolved in a mixture of 25 ml. of pyridine and 2.5 ml. of triethylamine
and the solution heated to reflux for 45 minutes. After cooling overnight,
the crude dye was collected on a buckner, washed with ethyl alcohol and
crystallized from dimethylformamide. 1.5 g. of pure dye were obtained.
M.P. = 154.degree.-5.degree. C. .nu. max. - 489 nm. (ethyl
alcohol-dimethylformamide).
EXAMPLE 22
2-p-diethyl-amino-styryl-3-ethyl-5,7-dichloro-6-methyl-benzoxazole
ethyl-sulfate
##STR27##
A mixture of 3.6 g. of 2,6-dimethyl-3-ethyl-5,7-dichloro-benzoxazole
ethyl-sulfate and 1.77 g. of p-diethylaminobenzaldehyde in 10 ml. of
acetic anhydride and 5 ml. of acetic acid was boiled for 10 minutes.
After cooling, the reaction mixture was poured into ethyl ether; the pick
cake, thus obtained, was ground in a mortar by washing with ethyl ether,
collected on a buckner and dried. The raw dye was purified by washing it
repeatedly with ethyl alcohol. 3.5 g. of pure dye were obtained with ethyl
alcohol. .lambda. max. = 525 nm. (ethyl alcohol).
EXAMPLE 23
3,3'-diethyl-5,6-5',6'-tetrachloro-thiacarbocyanine ethylsulfate
##STR28##
A mixture of 2.2 g. of 2-methyl-5,6-dichlorobenzothiazole and 2 ml. of
diethylsulfate was heated at 120.degree. C. for 20 minutes. After cooling,
the pick cake was ground in a mortar by washing with ethyl ether and
dried. The solid product, thus obtained, was dissolved in 15 ml. of
anhydrous pyridine and 1.8 ml. of triethylorthoformiate and the solution
heated to reflux for 40 minutes. After cooling, the crude dye was
precipitated with a large quantity of ethyl ether, collected on a filter
and dried in a desicator. After boiling repeatedly with ethyl alcohol and
ethyl ether, 0.8 g. of pure dye was obtained. M.P. -
260.degree.-270.degree. C. .lambda. max. = 578 nm. (ethyl alcohol).
EXAMPLE 24
3,3'-diethyl-5,6-5'-6'-tetrachloro-thiacarbocyanine bromide
##STR29##
The dye was prepared as reported in Example 23, precipitating the dye with
a potassium bromide aqueous solution. M.P. = 233.degree.-238.degree. C.
.lambda. max. - 568 nm. (ethyl alcohol).
EXAMPLE 25
3,3',9 -triethyl-5,6-5',6'-tetrachloro-thiacarbocyanine ethyl-sulfate
##STR30##
A mixture of 2.2 g. of 2-methyl-5,6-dichlorobenzothiazole and 2 ml. of
diethylsulfate was heated at 120.degree. C. for 20 minutes; the pick cake,
obtained by cooling, was ground in a mortar by washing with ether and
dried. The solid, thus obtained, was dissolved in 20 ml. of anhydrous
pyridine and 2 ml. of triethylorthopropionate and the solution boiled for
40 minutes. After cooling, the reaction mixture was poured into ethyl
ether; the crude dye was purified by boiling repeatedly with water. 0.5 g.
of pure dye was obtained. M. P. = 134.degree. - 139.degree. C. .lambda.
max. = 5.77 nm. (ethyl alcohol).
EXAMPLE 26
3,3',9-triethyl-5,6-5',6'-tetrachloro-thiacarbocyanine-p-toluene-sulfonate
##STR31##
The dye was prepared as reported in Example 25, by using
ethyl-p-toluene-sulfonate, instead of diethyl-sulfate, as quaternary
agent. M.P. = 129.degree.-133.degree. C. .lambda. max. = 589 nm. (ethyl
alcohol).
EXAMPLE 27
3,3'-diethyl-5,7-5',7'-tetrachloro-thia-carbocyanine iodide
##STR32##
The dye was prepared as described in Example 23, using
2-methyl-5,7-dichloro-benzothiazole instead of
2-methyl-5,6-dichloro-benzothiazole and employing potassium iodide as
precipitating agent of the dye. M.P. = 234.degree.-240.degree. C. .lambda.
max. - 569 nm. (ethyl alcohol).
EXAMPLE 28
3,3',9-triethyl-5,7-5',7'-tetrachloro-carbocyanine iodide
##STR33##
The dye was prepared as described in Example 25, using
2-methyl-5,7-dichloro-benzothiazole, instead of
2-methyl-5,6-dichloro-benzothiazole and precipitating the crude dye with
an aqueous solution of potassium iodide. M.P. = 225.degree.-230.degree. C.
.lambda. max. - 561 nm. (ethyl alcohol).
EXAMPLE 29
2-methyl-5,7-dichloro-benzoxazole
##STR34##
A mixture of 61.8 g of 2-acetylamino-4,6-dichloro-phenol and 4.12 g of
anhydrous sodium acetate was heated for some minutes, obtaining a liquid
slurry which was distilled under reduced pressure, by collecting the
fraction distilled between 145.degree. - 155.degree. C at 1,4 mm Hg. The
distilled oil upon standing became a solid which was crystallized from
ligroin, obtaining 28 g of 2-methyl-5,7-dichloro-benzoxazole. M.P. =
110.degree. - 113.degree. C.
Percent analysis - C% Calc. 47,56, Found 47,41. H% 2,49, 2.54. N% 6,93,
6,90.
EXAMPLE 30
2-methyl-3-ethyl-5,7-dichloro-benzoxazole ethyl-sulphate.
##STR35##
A mixture of 2.0 g of 2-methyl-5,7-dichloro-benzoxazole and 2.5 ml of
diethyl-sulphate was heated at 150.degree. C for 40 minutes. By cooling, a
solid cake was obtained. It was then ground in a mortar by washing
repeatedly with ethyl ether. The product was employed without further
purification.
EXAMPLE 31
3,3'-diethyl-5,7-5',7'-tetrachloro-oxa-carbocyanine perchlorate
##STR36##
A mixture of 3.5 g of 2-methyl-5,7-dichloro-benzoxazole-ethyl-sulphate in
15 ml of pyridine and 2.5 of triethylorthopropionate was heated to reflux
for 90 minutes. After cooling, the reaction mixture was poured into ethyl
ether. The yellow gum which separated was washed with ethyl ether and
dissolved in a minimum quantity of hot ethyl alcohol. To this solution, an
ammonium perchlorate aqueous solution was added. The dye, separated upon
cooling, was collected on a buchner and washed with ethyl alcohol, water
and ethyl ether. 0.1 g of dye was obtained having M.P. = 268.degree. -
271.degree. C. .lambda. max = 498 nm (ethyl alcohol-dimethylformamide).
EXAMPLE 32
3,3'-dimethyl-5,7-5',7'-tetrachloro-oxa-carbocyanine perchlorate
##STR37##
The dye was prepared as reported in the previous example using the N-methyl
quaternary salt of the base. M.P. = 275.degree. - 8.degree. C .lambda. max
= 496 nm (ethyl-alcohol-dimethyl formamide).
The dyes of the present invention are powerful desensitizers for
light-sensitive silver halide emulsions and therefore can be used in those
photographic elements wherein desensitization is required, such as for
instance in the manufacture of emulsions used for the production of direct
positive images, as described by Kendall and col. in U.S. Pat. No.
2,541,472 or in U.S. Pat. No. 2,669,515 and by Hillson and col. in U.S.
Pat. No. 3,062,651, etc.
The cyanine dyes of this invention, such as for instance those represented
by examples 11, 12, 13, 14, 18, 24, 27, 28 are useful electron acceptor
spectral sensitizers for direct positive emulsions, since the direct
positive emulsions, which contain them, have an improved sensitivity.
To prepare photographic emulsions, the dyes according to the present
inven | | |
