DE1937251C - Direct positive photographic silver halide emulsion - Google Patents

Description

The invention relates to a direct positive, an indole dimethine cyanine dye and optionally a silver halide photographic emulsion containing a color coupler.

It is known, for example, from U.S. patent documents 2,930,694 and 3,314,796, direct positive photographic .silver halide emulsions, dimethine cyanine dyes and to add trimethine cyanine dyes which have an 1-alkyI-2-phenylindole ring. Direct positive photographic silver halide emulsions containing such dyes, no matter whether it is a dimethine or trimethine dye have corresponding sensitivities.

It is also known from Belgian patent 695 360 to use direct positive photographic Silver halide emulsions 1,2-diarylindole trimethine cyanine dyes to add.

The object of the invention is to provide direct positive silver halide emulsions indicate whose sensitization remains stable even in the presence of color couplers within long storage times, and which characterized by high sensitivity.

The subject matter of the invention is based on a direct positive, an indole dimethine cyanine dye and optionally a silver halide photographic emulsion containing a color coupler and is characterized in that the cyanine dye in the emulsion is one of the formula

Z

R ₁ -N (= CH-CH) "= fC-L ₁ = L ₂ -C

N-R, X contain color formers or color couplers, and / was both a monomeric and a polymeric Color couplers, e.g. B. one of the usual color couplers of the pyrazolone, phenolic and naphtholic type Compounds, heterocyclic compounds and the type of open-chain coupler with a reactive methylene group, as found in a wide variety of patents, for example the USA patents 2,600,788 and 2,983,608, bekanni

ίο are. In direct positive, containing a cyan in dye Silver halide emulsions according to the invention with a color coupler thus remain the spectral The emulsion remains sensitive even if the emulsion is stored for a longer period of time.

The direct positive silver halide photographic emulsions of the invention are notable by a considerably greater sensitivity, generally about twice as great a sensitivity compared to corresponding emulsions

from which a corresponding 1,2-diaryltrimethine indole dye contain.

The use of the new cyanine dyes leads, in particular, to improved incubation stability, in particular the loss of _Dax which usually occurs during incubations being reduced and no losses in sensitivity occurring. These improvements can be achieved if the emulsions are used in conventional black-and-white developers, e.g. B. Elon hydroquinone developers, and usual color developers.

In the structural formula given, L ₁ and L ₂ preferably have the meanings of methine radicals optionally substituted by an alkyl radical or an aryl radical, ie. For example, L, and L ₂ can be methine residues of the following structural formulas:

and

-CH = C (CH.,) =

-C (C ₁ H,) =

contains, v / orin mean: L ₁ . L _{2 is in} each case an optionally substituted methine radical, R an optionally substituted alkyl. Alkenyl or aryl, R ₂ and R ₃ optionally substituted aryl radicals c. R _{4 is} a hydrogen or halogen atom or an alkyl, alkoxy, aryloxy or nitro resl. / 1 = I © der 2, Z the five or six-membered units to complete a common sensitiser. leteroeyclis

By the 1,2-di- ■ rylindole dimethine dyes used according to the invention will have better inventory stability and / or higher sensitivity compared to known corresponding emissions with corresponding 1-alkyl-2-arylindole rings achieved.

A particular advantage of the cyanine dyes used according to the invention is that they do not lose their sensitizing effect in emulsions which contain color formers or color couplers. It is known that practically all photographic color couplers tend to rob sensitizing dyes of their effectiveness in direct positive emulsions. As a result, the new cyanine dyes of the invention are advantageously suitable for the preparation of direct-sensitive photographic silver halide mules which have an R, the meaning of an optionally substituted alkyl radical. so it preferably has from 1 to 12, in particular from 1 to 4 carbon atoms. R ₁ can thus be, for example, a methyl, ethyl. Propyl, isopropyl. Butyl, hexyl, cyclohexyl. Decyl or dodccyl radical. If R, has the meaning of a substituted alkyl radical, the. ^ R can be, for example, a hydroxyalkyl radical. z. B. a // - Hydroxyüthyl- or a r -.- Hydroxybutylrest or an Alkoxyalkylrcst, z. B. a // - Methoxyäthyl- or m-Butoxybutylrest. or a carboxyalkyl radical, e.g. B. a / f-Carboxyäthyl- or / n-Carboxybutylrest. or a sulfoalkyl radical. z. B. a / i-sulfoethyl or «i-sulfobutyl radical. or a sulfaloalkyl radical. ζ. B. a // - sulfatoethyl or m-sulfatobutylrcst. or an acyloxyalkyl radical. /. B. a // - Acetoxyäthyl-, j-Acctoxypropyl- or fi-Butyryloxybutylrest, or an Alkoxycarbonylalkylrest, z. B. a // * methoxycarbonylethyl or m-ethoxycarbonylbutyl radical, or an aralkyl radical. for example a benzyl or phenethyl radical.

If R _{1 has} the meaning of an optionally substituted alkenyl radical, this preferably has up to 4 carbon atoms and can, for example

fts consist of an allyl, 1-propynyl or 2-butynyl radical.

If R _{1 has} the meaning of an optionally substituted aryl radical, this preferably exists

1937 3

»From an aryl radical of the phenyl or nitro series, i.e., R can be, for example, a phenyl-, ToIyI-, N.iphthyl, methoxyphenyl or chlorophenyl radical.

R, and Rj preferably consist of aryl radicals of the phenyl or naphthyl series, ie, R ₁ and R ₃ can each be, for example, a phenyl, toly, naphthyl, chlorophenyl or nitrophenyl radical.

If R _{4 has} the meaning of an alkyl radical, this preferably has 1 to 12, in particular 1 to 4 carbon atoms, ie, R ₄ can be, for example, a methyl, ethyl, propyl, iso-

up to U in particular 1 to 4 carbon

rest. ie, R ₄ can be, for example, a phenoxy or tolyloxy radical.

R _{4 has} the meaning of a halogen atom. this consists, for example, of a chlorine or bromo aiom.

For example, X can be chloride, bromide. Iodide-. Sulfamate. Perchlorate p-toluenesulfonate or Methyl sulfate anion.

Z represents the complement to some nasty desensitizing effect. 5- or 6-membered, heterocycle -hen ring represents the atoms required. The ring completed by Z can thus be, for example, a nitrobenzothiazole ring, e.g. B. a 5-nitrobenzothiazole. 6-N-trob ^ nzothiazole or S-chloro-o-nitrobenzothiazole ring: a nitrobenzox; i / ol ring, e.g. B. a 5-nitrobenzoxazole-. 6-nitrobenzoxazole or S-chloro-o-nitrobenzoxazole ring: a nitrohenzosylcnazole ring. ζ B. a 5-nitrobenzoselenazole-. 6-nitrobenzoselenazole or D-chloro-o-nitrobenzoselenazole ring: an imidazo [4,5-b] quinoxaline ring, e.g. An imidazo [4.5-b] quinoxaline ring, e.g. B. a 1,3-dialkylimidazo [4.5-b] quinoxaline ring. such as a 1,3-diethylimidazo [4.5-b] quinoxaline or 6-chloro-1,3-diethylimidazo [4.5-b] quinoxaline ring; a 1.3-dialkylimidazof4.5-b] quinoxaline ring. for example a 1.3-diallylimidazo [4,5-b] quinoxaline or oJ-dichloro-1.-vdiallylimidazo [4 .. 'ib] quinoxaline ring, or a 1,3-diarylimidazo [4,5-b] quinoxaline ring. 1 .. B. a 1,3-Diphcnylimida / o [4.5-b] quinoxaline or 6-chlorol, 3-diphcnylimidazof4.5-b] quinoxaline ring: a 3.3-dialkyl-3H-pyrrolo [2.3-b] pyridine ring, z. B. a 3.3-diniethyl-31l-pyrrolo [2.3-bjpyridine or 3.3-diethyl-3 H - pyrrolof2.3 - b] pyridine ring; a 3,3-dialkyl-311-nitrmndole ring. r. B. a 3,3-dimethyl-5-nitro-311-indole-. 3.3-Diiithyl-5-nitro-3H -indole- or 3.3-Dimethyl-6-nitro-3H-indole ring: a thiazolof4.5-b] chini) lin ring or a Nilroehinolinring, /..B. a 5-nitroquinoline or ft-nitroquinoline ring.

Z can also represent, for example, the atoms required to complete of a nitrothiazole nitronaphthothiazole, nitrooxazole, Nitronaphthoxazole, nitroselinazole, nitronaphthoselcnazole or nitropyridine rings.

Those of the structural formula given have proven to be particularly advantageous dyes. where Z stands for the non-metallic atoms necessary to complete an imidazof4,5-b] quinoxa- 6 <s linringes are required.

Particularly advantageous desensitizing heterocyclic rings are those which, when included in 'J

251 ~

In the form of a symmetrical carbocyanine dye and a gelatin-silver chlorobromide emulsion are added, their silver halide to 4 <) mol percent of chloride and 60 mol percent consists of bromide, at a concentration of 0.01-0.2 grams of dye per mole of silver, by electron capture lead to an at least 8n% loss of the emulsiou's sensitivity to blue, when exposed sensitometrically and for 3 minutes in a developer of the following composition ^ development at room temperature:

Nalmimsulfil (anhydrous 90. "

BS ^ Äim *. :: ■ ■■■■ S f

Very particularly advantageous desensitizing effects Rings are those which are in the form of a symmetrical carbocyanine dye in the described Way tested to a practically complete desensitization of the test emulsion to bluer Conduct radiation, d. H. to a greater than about 90 to 95% loss in sensitivity to blue radiation.

The for the preparation of the direct positive photographic silver halide emulsions according to the Ετfindung suitable asymmetrical cyanine dyes of the specified structural formula can be easily produce.

_{If L 1} and L ₂ in the formula given represent unsubstituted methine radicals, the dyes can be prepared by reacting a mixture of

_{ejnem, do, the fo dcn S, ru} kturformel:

C - CHO

wherein R ₂ , R ₃ and R _{4 have} the meaning already given, with

2) a heterocyclic compound of the following structural formula:

R ₁ - .. N (= CH CH) ₁₁ ^ t ¹ C-CH ₃
I.
χ

in which n, R ₁ , X and Z have the meanings already given. Preferably, approximately equimolar amounts of the reactants I) and 2) are reacted with one another in an inert solvent, for example hot acetic anhydride. The resulting crude dye can then be recrystallized by one or more recrystallizations from a solvent , for example methanol .

Has in the given formula L ₁ the meaning of a substituted Meihin residue, z. B. of a radical of the formula - C (CHj) = or -C (C ₁₁ II ₅ ) =, such dyes can be prepared by reacting an indole of the formula given with a quaternary salt of the following structural formula:

R ₁ -Nf = CH-CH) _n = C-CH ₂ -R ₅ X

wherein R ₁ , Z, η and X have the meaning given and R ₅ z. B. is a methyl or phenyl radical. Has in the given formula L ₂ the meaning of a substituted methine radical, z. B. a radical of the formula —C (CH ₃ ) =, such dyes can be prepared by reacting a fine indole of the formula

wherein R ₂ , R ₁ and R _{4 have} the meaning given, with a halogen, z. B. Chlorine compound of the following structural formula:

Z.

R ₁ -Nf = CH-CH) _n = C-CH = C-CHj X '

Adhesive metal compounds with a metal that is more electroposilient than silver are, for example, compounds of gold, rhodium, platinum, palladium, iridium and the like, with soluble salts being preferably used, e.g. B. potassium chloroaurate, aurichloride, (NH ₄ I ₂ PdCL, etc.

The ones used to obscure the emulsions

. determined concentrations of reducing agents

Compound and metal compound (e.g. metal salt)

ίο can be very different. It has proven advantageous to use about 0.05 to 50 mg of reducing compound per mole of silver halide and 0.5 to 15.0 mg of metal compound per mole of silver halide. Particularly advantageous results are obtained when the concentrations of reducing compound and metal compound are in the lower ranges of the specified concentration ranges.
The concentration of the added cyanine dye (s) can also vary widely. It has proven to be expedient to use about 50 to 2000 mg, preferably about 400 to 800 mg of dye per mole of silver halide.

Particularly advantageous veiled direct positives.

Emulsions containing a cyanine dye are those whose silver halide grains are fogged in such a way that they result in a density of at least 0.5 when they are developed without being exposed for 5 minutes at 20 ° C. in a developer of the composition given below, when the emulsion has been applied to a layer support in such a way that 50 to 500 mg of silver are present ^{on a support area of 0.09 m 2.}

Cl

40

wherein R ₁ , Z, η and X have the meaning given, in the presence of an acidic catalyst, for. B. phosphorus oxychloride.

The direct positive photographic silver halide emulsion of the invention may contain one or contain several cyanine dyes of the structural formula given. The silver halide photographic emulsion according to the invention can be obfuscated by any of the usual known methods be, for example, by the action of L'cht 5η or by the action of chemical abrasives. for example stannous chloride, formaldehyde. Thiourea dioxide and the like

In a particularly advantageous manner, the emulsion have been obscured by adding a reducing compound, for example thiourea dioxide, and a compound of a metal more electropositive than silver, for example one Cioldsalzes, z. B. potassium chloroaurate, as is known from British patent 723 019.

Advantageous reducing compounds which can be used to obscure the direct-positive photographic silver halide emulsion containing a cyanine dye according to the invention are, for example, stannous salts, / .. 13. Stannous chloride. Hydra.-r, sulfur compounds, / .. B. Thiohiirnstoffdioxyd. Phosphonium salt c. z. B. Tetra-hydroxymethyl) -phosprionriimehlorid and the like. Advantage developer

N-methyl-p-aminophynol sulfate 2.5 g

Sodium sulfite (anhydrous) 30.0 g

Hydroquinone 2.5 g

Sodium metaborate 10.0 g

Potassium bromide 0.5 g

Made up to 1.0 1 with water

The new cyanine dyes described have proven to be extremely effective Elcktronenakzeptoren Proven for high sensitivity direct positive silver halide emulsions; H. for emulsions with fogged silver halide grains and a compound that traps or accepts electrons, for example of the type known from Belgian patent 695,366.

Such silver halide emulsions have silver halide grains which are so fogged that they are. if they are applied in the form of a pholographic silver halide emulsion to a layer support in such a way that they are developed for 6 minutes in a developer at 20 ^° C. of the following composition:

N-methyl-p-aminophenol sulfate 2.5 g

Sodium sulfil (anhydrous) 30.0 g

Hydroquinone 2.5 g

Sodium metaborate 10.0 g

Potassium bromide 0.5 g

Made up to 1.0 l with water

a maximum density of at least I result in a maximum density by at least; 30% greater than the maximum density in a corresponding manner on a substrate

. clragenen emulsion, which was developed for 6 minutes in Clem dikes developer hoi 20 ( 'post-Il ¹ IH it about IO minutes at 20 C in a Bleichlad the following composition:

Potassium Cyanide 50 mg

Glacial acetic acid 3.47 ml

Sodium acetate 11.49 ml

Potassium bromide 119 mg

Made up to 1.0 l with water

has been bleached.

The silver halide grains of such emulsions lose at least about 25 percent. generally at least about 40% of their haze when placed in a potassium cyanide bleach bath at 20 C for 10 minutes the specified composition can be bleached.

Such a loss of smear can be illustrated by plotting the silver halide grains in FIG In the form of a photographic silver halide emulsion on a support to achieve a maximum Density of at least about 1.0 after 6 minutes of development at 2ºC in a developer the specified composition (Kodak DK-50) and comparison of the density of such an emulsion layer with that of a corresponding layer that was left in the same developer for 6 minutes at 20 ° C after being in the potassium cyanide bleach bath specified for about 10 minutes at 20 ° C Composition has been bleached. As stated earlier, the maximum density is the unbleached Layer at least about 30% larger, generally at least 60% larger, than the maximum Density of the bleached layer.

The silver halide grains of the direct positive silver halide emulsion according to the invention can be made from any of the commonly known silver halides which are suitable for the preparation of direct positive photographic silver halide emulsions are. d. H. for example from silver bromide. Silver iodide. Silver chloride. Silver chlorobromide. Silver bromoiodide and silver chlorobromoiodide.

Such direct-positive silver halide emulsions according to the invention have proven to be particularly advantageous whose silver halide grains have an average grain size of less than about I microns, especially less than about 0.5 microns. The silver halide grains can be regular be and have any of the commonly known shapes, i.e. H. for example cubic or octahedral be, for example, in the Belgian patent specification 695 366.

Advantageously, the direct positive photographic silver halide emulsion according to the Invention a uniform silver halide grain diameter frequency distribution on. as for example from the Belgian patent specification 695 366 is known. Advantageously, therefore, have at least 95 percent by weight of the silver halide grains a diameter knife that is no longer al-, do τ 40%. preferably deviates from the mean grain diameter by no more than ± 30%.

The minimum grain diameter, i.e. H. the average Grain size. HiBi determine yourself according to known procedures, for example according to the one from f> s the magazine "The Photographic Journal". Vol. LWIX 11949 !. p. 33i> to 33S. known procedures.

The fogged silver halide grains of this type of direct positive photographic silver halide emulsions according to the invention produce a density of at least 0.5. when exposed without to be for 5 minutes at 20 C in a developer of the specified composition (Kodak DK-50) if they are in the form of an emulsion with a layer of starch corresponding to 50 up to about 5 (X) mg silver per 0.09 nr on a layer support be applied.

Such direct-positive photographic silver halide emulsions have proven to be particularly advantageous proven, the silver halide of which consists of at least 50 mole percent of silver bromide, with whole particularly advantageous emulsions are those which consist of silver bromoiodide emulsions, especially those which contain less than about 10 mole percent iodide.

The direct-positive photographic silver halide emulsions can expediently be applied to conventional layer supports in such a way that the silver coverage amounts to about 50 to about 5 (K) mg of silver per 0.09 m ^{2 of support} area.

The color couplers can be used in direct positive silver halide emulsions incorporated according to the invention, for example, with conventional color coupler solvents wv »'den. as for example from the USA patent specification 2,322,027 are known.

Color couplers can be added with particular advantage to such direct positive silver halide emulsions, the silver halide grains of which have a core or a center made of a water-insoluble silver salt have and an outer shell made of a water-insoluble silver salt, which turns into silver, developed without being exposed. The production of such emulsions is, for example, from U.S. Patent 3,367,778 is known.

For the production of direct positive silver halide emulsions according to the invention with color couplers it has been found particularly advantageous to use di-n-butyl phthalate as the coupler solvent. Particularly advantageous color couplers are the known Cjanamidophcnol couplers. like them for example from US Pat. No. 2,895,826, and also combinations of one Amidophene coupler and a phenolic blue-green coupler of the type known, for example, from ISA patent 2,474,293.

The addition of the new cyanine dyes to the L-emulsion takes place in an advantageous manner to the washed, finished silver halide emulsion, the or the It is desirable to distribute dyes as uniformly as possible in the emulsion. Incorporation the dyes in the emulsion are carried out by customary known methods. That’s the way it was For example, the dyes have proven advantageous in the form of solutions in suitable solvents to be incorporated into the emulsion, for example in solutions, their solvent from Mrthanol. Isopropanol. Pyridine and water or mixtures thereof.

The direct positive silver halide emulsion of the invention can be prepared using one of or more of the commonly known hydrophilic colloids can be prepared, for example using of gelatin. Albumin. Agar Agar. Gum arabic. Alginic acid, or even in contrast to naturally occurring binders synthetic hydrophilic resins. /. B. polyvinyl alcohol

109 637 3V

Polyvinyl pyrrolidone. Cellulose ethers. partially hydrolyzed Cellulose esters, especially partially hydrolyze CeIIu loseaceta ten

The binders can also decompose dispersed polymerized vinyl compounds hold, as for example from the LSA patents 3142568. 3193 3X6. 3062674 and 3220X44 are known. Such polymerized vinyl compounds consist, for example, of insoluble in water Polymers of alkyl acrylates and alkyl η Bid acrylates. Acrylic acid. Sulfoalkyl acrylates and or sulfoalkyl methacrylates

The direct positive photographic silver halide

Senide emulsions according to the invention can be applied to conventionally known photographic layer supports wear, for example on those made of glass. Film carrier dus cellulose acetate. Cellulose acetate butyrate. Polyester. C B polyethylene terephthalate. Paper, baryta paper, paper coated with polyolefins, ζ Β with Polyethylene or polypropylene coated paper. if necessary to improve the emulsion ■ dhesion may have been irradiated with electrons

The silver halide photographic emulsions according to the invention can be mixed with conventionally known ones Hardening agents are hardened, for example Aide-:, kydhärtem. ζ. Β formaldehyde and mucochloric acid. Aziridine hardeners. Hardeners, the derivatives of Dioti is, or Owpolysaccharide, ζ Β oxidized Starch or oxidized vegetable gums.

The emulsions can also contain additional additives such as are usually added to direct-positive photographic emulsions, for example lubricants or coating aids. Stabilizers, sensitivity increasing compounds, absorbing dyes. Plasticizers. GegebenenTalls the emulsions can of "Eiteren additional spectral sensitizing dyes Furthermore, the emulsions can optionally be developed with solutions that color couplers or other color-producing connects _4C fertilize included

The emulsions can also be developed with customary developers, for example polyhydroxybenzenes. Aminophenols and 3-pyrazolidones.

The following examples are intended to illustrate the invention in more detail.

For the specified processes for the preparation of the cyanine dyes used according to the invention No protection is claimed for their preliminary products.

Example 1 describes the manufacture and use of a trimethine dye Belgian patent 695,360, this example serving as a comparative example.

Example I.
i \ comparison example i

A. Manufacture of l.r.2.2'-Tetrapheny! - ^

3.3 indoiocarbocyanine perchlorate

2.S3 and 1.2-diphenylindole were dissolved in 25 ml of acetic acid. whereupon the solution was heated to boiling. Then 1.99 g of p-toluenesulfonic acid and finally 4 g of tinethoxypropene were added, f.5 After 1 minute, the mixture was allowed to cool and poured into 150 ml of water which contained 3 g of sodium perchlorate. The dye formed was filtered and purified by crystallization from ethanol. The howl of the purified dye was 0.7 g. 2l according ⁿ o of theory Melting point of dye lan at 232-233 C idjc.i

B. Use of the dye

The dye prepared in the manner described and containing two 1,2-diphenylindole rings was on its usefulness as an electron acceptor and spectral sensitizing dye for eiiu directly posi ti se veiled silver halide idemulsior according to the following procedure; ictesiet.

Fine gelatin silver broinoiodide emulsion mn 2.5 mole percent iodine id as a halide and one through The average grain size of the silver halide grains about 0.2 microns was prepared by using a aqueous solution of potassium bromide and potassium iodide and an aqueous solution of silver nitr.i at the same time to a vigorously agitated aqueous gelatin solution at a temperature of 70 C inside the hall over a period of 35 minutes. The emulsion was then quenched, noodle and washed with cold water in the usual manner

The emulsion was dam with a-ir reduce effective connection and a gold connection disguised by initially adding 0.2 mg thiourine mofl Dioxide added per mole of silver, the emulsioi Heated to 65 C for 60 minutes. 4.0 mg of potassium chloroaurate per mole of silver are added and the Fniul sion was heated again 60 mnrites to 65 ° C

The Far! ¹ fabric was made in the manner described here. provided veiled emulsion at a concentration of 650 mg per mole of silver added

The resulting emulsion was then applied to a. usual cellulose acetate film layers in this way worn that on a support surface of 0.Ov: r 100 mg of silver and 400 mg of gelatine were used

A test strip of the record obtained;.: - materials was then in a usual sensitonic: of the Eastman Ib type, where a tungsten lamp was used as the Lic ': source Dar .'... the exposed recording material was then stored in an I for 6 minutes at room temperature develop winder of the following composition,

N-methyl-p-aminophenol sulfate 2.0 g

Sodium sulfite (anhydrous I QO.0 *:

Hydroquinone S.O ^

Sodium carbon.it (Monohuir.it). 52.5> j

Potassium bromide 5. (^ Ll

\ Ih water filled to 1.0 i

The ^ recording material was then used in the following way: " Way fixed, washed and dried. The err ..: The results are presented in the following 1 cure 1 compiled

H c 1

ρ 1

The experiment was repeated, iecU \ this time such a dye was used! which was produced in the manner described but using 1-Mc; hyi-2-phcr.) indole.

As can be seen from the following table I, lie! Sensitivity and contrast when using this The dye is slightly higher than when it is used d Dye of Example 1. The T

Belle I shows, however, that both the emulsion of the Example I and the emulsion of Example I Λ do not show the favorable results, as they do with Use of originally used dyes be educated.

Example 2

Λ. Production of I.3-I3iäthyl-IM'-diphcnyl-

imidazof4.5-b] quinoxatino-'V-indolocarbocyanine p-toluenesulfonate

4.12 g (0.01 mol) 1.3 - diethyl - 2 - methyl [4.5 - b J-

# hinoxalinium-p-toluenesulfonate and 2.97 g (0.01 mol) IJ-Diphcnylindol-.Vcarboxaldehyd in 25 ml of vinegar | Fluorine anhydride were boiled for 1 minute heated. After the reaction mixture had cooled, it was diluted with ether. The out- The precipitated dye was filtered off and washed with ether I wash. After two recrystallization from topropyl alcohol, .1.2 g of pure dye, ent Correspondingly 46% of theory with a melting point of ton 231 to 232 C (dec. »Obtained.

B. Use of the dye

The dye that acts as a desensitizing agent hung a 1,2-diphenylimidazof4,5-b] quinoxaline ring tnt kept, was on his reversal. Awareness and Stability properties according to that in Example I.

Beschricbt.icn procedure tested. The received The results are again summarized in Table I below.

The table shows that when this dye is used, densities of 1.80 and 0.04 for the unexposed or exposed areas can be achieved with a maximum sensitivity at 545 nm and a relative sensitivity of 13R0.

From these data it can be seen that the dye ίο is an extremely effective electron acceptor and an excellent spectral sensitizing dye for fogged direct positive emulsions is. As can also be seen, the stability properties of this dye are extraordinary Cheap.

Example 2A

The procedure was repeated, but this time a dye was used which is associated with I-methyl

zo 2-phenylindole was produced. As can be seen from table I results in about the same densities and sensitivities when using this dye obtained as when using the dye of Example 2. When storing the emulsion however, as can be seen from the table, a density loss of 55.6% occurs. whereas the loss of density when using the dye of Example 2 is only about 36.7%.

Example 3
A. Preparation of IJ-diphenyl-.V-ethyl-fc'-nilroindolothiacarbocyanine-p-toluenesulfonate

NO,

CH-CH

C ₂ H ₅

The dye was prepared according to the procedure described in Example 2 with the exception however, that 3.95 g (0.01 mol) of 3-ethyl-2-methyl-6-nitrobenzothiazolium p-toluenesulfonate instead of 1.3 - diethyl - 2-methylimidazo [4.5 - b] quinoxalinium p-toluoisulfonate were used. After two recrystallizations from methanol, 3.7 g of dye, corresponding to 55% of theory, were added a melting point of 271 to 272 C (dec.).

B Use of the dye

The dye prepared in the manner described, which contained a 3-ethyl-6-nitrobenzothiazole ring as a desensitizing ring, was reversed. Sensitization and stability properties according to the N ■ - QH _{5 described in Example I.}

QH ₅

Procedure tested. The results obtained are summarized in Table I below

As can be seen from the data obtained, the densities of the unexposed and exposed were Districts at 1.02 and 0.07. the maximum sensitivity was 570 nm and the relative Sensitivity was 1450.

The results obtained show that the dye substance an excellently effective electron acceptor and spectral sensitizing dye for before laminated direct positive emulsions.

Example 3 A

^{The dye 3. Λ} produced for comparison purposes shows significantly poorer properties than the corresponding dye according to the invention.

example

Preparation of 6-chloro-l.r.2'.3-tetraphenylimidazo [4.5-b] quinoxalino-3-indolocarbocyanine-p-toluenesulfonai

QH ₅

ei - ■ '■

N N

χ χ ,;

N N

CH = CH

N - QH,

OSO ₂ C ₇ H ₇

QH ₅ QH ₅

2046

i 937 251

The dye was according to the example 2 method described, with the exception, however, that 5.43 g (0.01 mol) of 6-chloro-2-methyll.3-diphynylimidazo [4,5-b] quinoxalinium p-toluenesulfonate instead of l..l-Diäihyl-2-mclhylimidazo [4.5-b] ehinoxaliniump-ioluenesulfonatcs were used. After two recrystallization from a mixture of methanol and isopropyl alcohol were 4.1 g of pure dye, corresponding to 50% of theory, with a melting point of 291 to 292 C (dec.).

B. Use of the dye

The dye produced in the manner described, the desensitizing ring contained a U-diphenylimidazo [4.5-b] quinoxaline ring, was tested according to the procedure described in Example I. The results obtained are in

of Table I below. From these results, it can be seen that the dye an extremely effective electron accelerator and spectral sensitizing dye for veiled direct positive photographic silver halide emulsions is. The densities obtained were 1.02 and 0.05 for the unexposed and exposed, respectively Districts, with a maximum sensitivity at 580 nm and a relative sensitivity of 1380. When the stability test was carried out, there was a loss of density of 27.5%. ·

Example 4Λ

For the sake of comparison, the procedure was repeated, this time, however, the dye used was that derived from! -Methyl-2-phcnylindole was produced. When this dye was used, the stability test was found to be a 34.5% loss in density.

Example 5
A. Preparation of lJ ^ -trimethyl-S-nitro-r ^ '- diphenylindo-S'-indolocarbocyanine-p-toluenesulfonate

CH., CH., ~ '\

CII = CU <NC "H ₅ OSO ₂ C ₇ H ₇

ν /

The dye was prepared according to the procedure described in Example 2 with the exception however, that 3.9 g (0.01 mol) of 1,2.3.3-tramethyl-5-nitroindolium-p-toluene sulfonate instead of 1.3 - diethyl - 2 - methylimidazo [4,5 - b] quinoxalinium p-toluenesulfonate were used. After two recrystallization from ethanol, 4.6 g of pure dye, corresponding to 69% of theory, obtained with a melting point of 175 to 177 C.

B. Use of the dye

The dye produced with a 1,3,3-trimethyl-5-nitro-3H-indole ring was tested according to the procedure described in Example 1. The results obtained are as follows later Table I compiled.

As can be seen from Table I, the densities of the unexposed and exposed areas were 1.06 or 0.05, with a maximum sensitivity at 575 nm and a relative sensitivity of 1380.

Example 5 A

The attempt with a dye repeated starting from l-methyl-2-phenylindole produced V; 'rdc. The received Sensitivities were about the same as when the dye of Example 5 was used.

However, it was found that the stability properties of the dye of Example 5 were significantly cheaper than those of Example 5A. So was when using of the dye of Example 5 found a C.htc loss of only 27.9%, whereas the Density loss when using the dye from Example 5 was 33.6%.

Example 6 Λ. Preparation of 1.2-diphenyl-r.3.3'-trimethyl-3-indolo-3 H-pyrrolo [2.3-b] pyridocarbocyanine perchlorate

CH ₃ CH,

CH =

CK) ₄

N N

CH,

The dye was made according to the procedure described in Bcispid 2 with the exception however, that a mixture of 1.74g (0.01 mol) 1.2 - dihydro - 1.3.3 - trimethyl - 2 - methylenpyrrolofts [2.3-b] pyridine and 1.9 g of p-toluopinic acid monohydrate instead of 1,3-diethyl-2-meihy! imida7.o- [~ 4.5-b] quinoxalinium-p-toluene sulfonate has been used. The crude dye was obtained by recrystallization

s; iiii! ii us methanol yereinigl. After two times Ijinkristallisalion were 2.5 g of dye, accordingly 40% of theory, with a melting point from 289 to 291 C (drc.).

B. Use of the dye

The dye obtained with a 1,3.3-trimethylpyrrolo ["2,3-b] pyridiiiring was tested according to the procedure described in Example I. The received The results are compiled in Table I below.

As can be seen from Table I, when the dye was used, densities for the unexposed and exposed areas of 1.06 and 0.05, respectively, were determined. The maximum sensitivity was 535 µm. with a relative sensitivity wedge of 1320 and a density loss of 29.2 ⁿ _n .

Example 6Λ

For the sake of comparison, the procedure was repeated this time, however, a dye was used based on 1-methyl-2-phenylindole was produced. When using this dye, densities of 0.88 and 0.05 were obtained. the maximum sensitivity was 535 nm and the relative sensitivity was 1320. The loss of density was 48.9%.

It follows that the color scheme of the example Figure 6 shows significantly improved stability compared to the dye of Example 6A.

ίο The dye of Example 6 is thus an excellent one effective dye for a fogged direct positive silver halide emulsion, being excellent spectral sensitizing properties and is an extremely effective electron acceptor.

The following table shows the Dyes 1, 2, 3, 4, 5 and 6 to dyes according to the invention, whereas the dyes are ΙΛ. 2A. 3Λ. 4Λ. 5Λ and 6A around comparison dyes is that starting from I-methyl-2-phenylindole were manufactured.

Hot example

IA

2Λ

3Λ

4Λ

5Λ

6Λ

l-'iirhstoIT-kon / cnlraiion
ηιμ MdI silver

650

150
500
500
650
5 (K)
350
500
500
440
450
850

V,

crequalsmalerial

Relative limpness

100 525 1380 1450 1450 1100 1380 1910 1380 1320 1320 1320 density

Max

1.02 1.44 1.80 1.80 1.02 0.97 1.02 0.98 1.06 1.04 1.06 0.88 min
Uc / irke

0.05
0.09
0.04
0.05
0.07
0.05
0.05
0.05
0.05
0.05
0.05
0.05

no comment

""""",-Loss
after I week
\ u (hc »; ihrunu at
• WC and 50 ¹ V
humidity
Γη) Maximum
sensitivity
(nm) 31.4 650 77.8 640 36.7 545 55.6 550 42.1 570 42.3 580 27.5 580 34.5 585 27.9 575 33.6 575 29.2 535 48.9 535

As can be seen from the data compiled in the table, the new cyanine dyes are not only excellently effective elephant acceptors and spectral sensitizing dyes for veiled ones direct positive silver halide emulsions but also lead / u emulsions with a greatly improved stability during storage of the Emulsions. In addition, the emulsions prepared using the new dyes have emulsions improved sensitivities to such emulsions. the corresponding dimcthin color ss substances, starting from 1-methyl-2-phcnylindolcn. contain and also better sensitivities than emulsions, the 1,2-diaryllrimelhinindolc as dyes contain.

Olcichgünstige results were then erhallen, <io when dircklposilive pholographische Silberhalogcnidemulsionen were prepared using the following cyanine:

l ^ -Diphcnyl-.V-älhyl ^ '- nilroindolooxaearbocyaninsal / cM.

1.2-1) iplicnyl-.V-melhyl-6'-nilroindolusclciiacarboevaninsal / en.

f'i 1.3-Diallyl-6-chloro-r.2'-diphenylimidazo [4.5-b] quinoxalino-3-indolocarbocyanine salts.

1.3-diethyl-5-methyl-2 .2 -diphynylimida / o | 4.5-b] quinoxalino-3 -indolocarbocyanine salt / cn.

5-methoxy-1.2-diphenyl-3'-ethyl-ft'-nilroindolothiacarbocyaninsal / en.

5'.6-dichloro-l.r.2'.3 -lelraphenylimida / o | 4.5-b | quinoxalino-3'-indolocarboi; yaninsii I / cn.

the salts, for example, as chlorides. Bromides. .Iodides, perchlorates and ρ-toluene sulfonalc used became.

As particularly advantageous dyes for the production of direct positive photographic silver halide emulsions According to the invention, those have also been found which have an 1- | nitroaryl) -2-arylindolling exhibit

In the following examples, the production such dyes are described sewing.

17 18

Example 7

Production of I _t 3-Diiith> l-I '- (4-nilrophcny |) -2'-phi.Miyliini (Jn ^ o [4,5-h | quinoxalino-

illlf

3'-indoiocarboeyanine-p-loluenesulfomite

C, H ₅

ν ν

|| '[V-CH = CFI-

'N ⁷ N

CFI ₅

Nf "-NO, OSO ₂ C ₇ H ₇

C _n Il,

HUg (0.003 mol) 1- | 4-nitrophenyl) -2-phenylindole-3-carhoxaldehyde and 1.23 g (0.003 mol) 1,3-Diithvl 2-methylimidazo [4.5-b] quinoxalinum p-toluenesulfonate in 10 ml acetic anhydride were 2 minutes heated to the boil. The cooled solution was then diluted with ether, whereupon the precipitated dye was filtered off. After two recrystallizations from methanol, 1.0 g of pure dye, corresponding to 45% of theory, with a melting point of ¹¹ ) 8 to 2 (M) C were obtained.

Example 8
Preparation of 3-ethyl-6'-nitro-1- (4-nitropheii> l) -2-phenyl-3-indoloihiaearboc} anine-p-toluenesulfonate

y— N C. Π = CH - γ C ₂ FI ₅ C ₁

OSO ₁ CH,

The dye was prepared according to the procedure described in Example 7, with the exception that. 1.2g (according to (K) 3 mol) 3-ethyl-2-methyl-6-nitrobenzolhiazolium-p-toluenesulfonal instead of 1.3-diethyl-2-melhy! imidazo [4.5-b] ehinoxalinium-p-loluenesulfonates were used. After two recrystallizations. " Methanol was 1.0 g of pure dye, corresponding to 45% of theory, with a melting point of 286 bi; 287 C (dec.) Obtained.

Example ^l )

Preparation of r..V.3'-Trimc (hyI-1- (4-nitrophcnyl) -2-phenyl-3-iiulolo-3 H-pyrrolo [2.3-bJpyridocarbofyanine-p-toluenesulfonate

FI ₁ C

CH,

( ji
VN

Ν- <ζ> -ΝΟ ₂ OSO ₂ CH ₇

c; h,

The dye was ^{prepared according to the method described in Example 7} , with the exception that a mixture of 0.52 g (0.003 mol) of 1.2-dihydro-1.3.3-trimethyl-2-methylene pyrrolo- [2.3-bJpyridine and 0.6 g. The dye was purified by recrystallization from ethanol. After two repeated use of crystallization, 0.9 g of dye, corresponding to 41% of theory, with a melting point of 251 to 253 ° C. (dec.) Were obtained.

Example IO

Production of 1,3,3-trimethyl-5-nitro-r- (4-nitrophcnyl) -2'-phenylindo-
-V-iridolocarbocyanine-p-toluenesulfonal

I,)

OSO ₂ C ₇ H ₇

CH ₁

CJU

The dye was made according to that described in Example 7 Process produced, with the exception, however, that »1.17 g (Ο, (ΚΟΜιιΙ) 1,2,3,3-tetramethyl-3 - niiroindolium - ρ - toluolsiilfona! instead of I..1 - Diulhyl - 2-methylimidazo [4,5 -b] quinoxalinium fi-toluenesulfonate were used. After two times crystallization from ethanol, 1.2 g became more pure larbslolT, corresponding to 56% of theory, with a melting point of 268 to 27 (1 C (dec.).

A comparison of the effectiveness of the dyes derived from l- (Milroaryl) -2-arylindole with Dyes from 1,2-diarylindoles shows that the dyes substituted by a nitroresl have a more favorable Incuhationsstabiliiät.

In the following the production of a veiled, direct positive silver halide emulsion according to the invention are described in more detail:

A. To 4.08 kg of a gelatin-silver chloride emulsion. «Lic contained the equivalent of KX) g sugar nitrate, were 0.017g of one of the dyes of the invention, for example the dye from Example 2 is added. The resulting emulsion was then coated on a non-glossy paper support lind flashed with white light, creating a Density of 1.2 was achieved when the emulsion layer with a developer of the composition given below after diluting with 2 parts of water was developed:

N-methyl-p-aminophenol sulfate .... 3.1g

_s sodium sulfu (dehydrated) 45 g

Hydroquinone 12g

Sodium carbonate (dehydrated) 67.5 g

Potassium bromide 1.9 g

Made up to 1.01 with water

ίο That in this way by exposure to light Fogged recording material is provided by a Wrattenfiker with image-appropriate exposure No.! 5 modulated light produces a direct positive image. B. 3.17 kg of a gelatin silver chloride emulsion,

containing the equivalent of 100 g of super nitrate, were heated to 40 C, whereupon the pH value of the Emulsion was adjusted to 7.8. Then 8 ml of a 40% formaldehyde solution were added, whereupon the emulsion was heated to 40 ° C. for 10 minutes

-o was heated. The pH was then adjusted to 6.0, whereupon 0.125 g of one of the dyes of the invention, for example the dye of Example 4, was added.

The emulsion was then applied to a support

applied. The recording material performed better for producing directly positive images Use quality.

Example Il

A. Preparation of 2- [2- (1-p-Acetamidophenyl-2-phenyl-3-indolyl) vinyl] -I 3-diethyl-1 H-imidazo [4.5-b] ethinoxalinium p-toluenesulfonate

C ₂ H ₅

N N

v- CH = CH - ^ N- <

NHCOCH., 'OSC) ₂ C ₇ H,

N N

The dye was used according to the example 2Λ indole-3-carboxaldehyde. The color

The method described prepared with the material was in a yield of 23% of theory

take that instead of 1,2-diphenylindole-3-carb-,

oxaldehyde this time I-p-acetamidophenyl-2-phenyl- 45 The melting point was 292 to 294 C.

B. Use of the dye in a concentration of 6 (X) mg / mol of silver in a conventional fogged silver bromoiodide emulsion gave the following results

Without dye. With dye

Relative sensitivity

"mm ^UI1 '

bclichlele Districts

1.70
1.64

K ,,

exposed

Districts

0.06
0.04

M.mm.ile H-sensitive wedge

(nm)

450
550

Example 12

A. Preparation of 2- [2- (1-p-acetamidophenyl-2-phenyl-3-indolyl) vinyl] -3-ethyl-6-nitrobenzothiazolium p-toluenesulfonate

CH- / N- / ~~ V-NHCOCH ₁ "OSOjC ₁ H ₇

P (L /

22nd

The dye was according to the Silberbromojodideinulsinn in Example 3Λ led to CnI-

manufactured according to the procedures described. The yield lowing results:

of dye was 61% of theory. The melting

point was 276 C.

B. Use of the dye

The use of the dye in a con / without dye tralion of 600 mg / mole of silver in a usual ratio. With dye

Relative sensitivity

166

575

helicliieie Districts

1.70 1.60

Maximum heliclileie Sensation Districts opportunity I n nil 0.06 450 0.04 550

example

Λ. Preparation of 2- [2- (l-p-Acetamidoplienyl-2-phenyl-3-indolyljviny! II.3.3-bimethyl-3 H-pyrrolo [2.3-b] pyijdinium p-loluo isulfonate

H, C CH.,

N - <> - NHCnCH., OSO ₂ C ₇ H,

QH,

The dye was written according to the silver bromoiodide emulsion shown in Example 9 Process made. The yield of 30 g results: dye was 44% of theory. The melting point of the dye was 195 to 197 C.

B. Use of the dye

The use of the dye in one concentration of 600 mg / mol of silver in a conventional

Relative D "" un- exposed Maximum Sensation bclichtlc Districts Sensation opportunity Districts opportunity 0.06 (nm) Without dye 166 1.70 0.03 450 With colorant 832 1.60 530

example

A. Preparation of 2- [2- | l-p-Acctamidophenyl-2-phcnyl-3-indolyl) vinyl] -6-ehloro-1,3-diphynyl-i H-imidazo [4.5-b] quinoxalinium p-toluenesulfonate

/. NN> ■■■ -;

Cl ~ i

I '

N N

CH-CH

NHCOCH., OSO ₂ C ₇ H ₇

QH.,

The dye was added according to the silver bromoiodide emulsion obscured in Example 4

schricbcncn process produced. The yield of r> o the following results:

Dye was 39% of theory. The melting point

of the dye was 320 to 322 C.

B. Use of dye 6? ^

The use of the dye in a con / without dye tralion of 600 mg mol of silver in a usual co-dye

450 580

23

H e i s ρ i c 1

Λ. I lays out 2- | 2- (lp-Aectamidophen> l-2phenvl-3-indolvl) vinvlJ- 1.3.3-1 riincth> l-5-nitr "> - 3 I l-indolium-p-toluenesulfonai

H ₁ C til,

CH ΠΙ

"NIlCOCH, OSO ₂ C-II-

N
CII.,

The pulp was dissolved by the selected silver bromoiodide emulsion, which led to the following procedure, which was essential in Example 5. The yield of the dye in the product was 34%. Its melting point was around
211 to 214 C.

H. Use of the dye ■

The use of the I arbstolTes in a Kotven without dye tration of 600 mg'Mol silver in a common use with dye

Relative
Flmpfind-
lich wedge IK., Un-
imagery
Districts n _m "
exposed
Districts 166 1.70 0.06 1105 1.65 0.03

Maximum"

Sensitive wedge

Ium]

450 560

(Icicli favorable results. as described in the preceding examples, were obtained when using di receive the following dyes:

CII CH

NO,

O, N

N (MI,

OSO, (MI-

O, N

CH = ■■■ CH

NHCOCH,

CIO ₄

(St.

IU

CH,

(Ml ₅

O, N

(Ή - CW

NO,

OSO, C-H-

(III

Cl

109 687

2046

25th

(H ₁ O

2 <ί

(H (Il

O, N ι -

N
C, M,

ΠΙ, ΠΙ CU;

N N

; ';.> cn cn

N N

(11, (11 (H, (ΊΙ, ίΙΙ (H,

N N

; ': n cn

N N

CII.CH (II,

Cl

C ,, IU

NO,

ClO ₄

NO,

OSO, C H-

NHC (K II, Mr

C ,, H,

N (H , ( II, Oll ( Il C. N N- N N (Il NO JIs N
CH , C Ή, ΟΗ : N C ₁ , 1 ( H Il N N cn Il N C. CJ NO

No,

OSO.C-Il

(VIh

(VMIl

N N

CH - (H.

N - · ■ - NO,

(IXl

2046

I 937 251

Manufacture of for manufacture

of the new dyes needed

/ wipe connections

The following describes the preparation of 1,2-aryl indole-3-carboxy-alkyl intermediate compounds are described in more detail, which are required for the preparation of the new cyanine dyes according to the invention.

Λ. 1,2 - [) iphenylindol-3-carboxulde dehyde

18 g of 1,2-diphenyl cylindrical. produced as in J. (hem.

fmc, 1944. p. 674., were in 40 ml ) dissolved imethylformamide, whereupon the solution obtained is a mixture of 7 ml of l'hosphoryl chloride and ml of dimethylformamide, cooled in an ice bath,

was added. The resulting mixture was then removed from the ice bath for 1 hour warmed up to !! 5C for a long time. After pouring on ice were K) OmI of an IO% sodium hydroxide solution added, whereupon the mixture on the Steam bath was heated for 10 minutes. The reaction product was from the cooled mixture nitrated and recrystallized from acetic acid. There were 17.2 g of pure aldehyde, corresponding to 86% of the Theory, obtained with a melting point of 232 to 234 C.

H. 1- (4-Nitrophenyl) -2-phenylindole

The connection can be established according to the following reaction scheme:

jc;, h _s

Il

NaOl I
DMF

N Na ¹

T-cji,

1- (4-Nitrophenyl) -2-phenylindole converts to the corresponding aldehyde by a Vilsmeicr reaction implement according to the following reaction scheme:

CHO

C ₁ , H,

! PL

I KON (CH,),

NC),

The aldehyde can then be used to prepare the dyes of Examples 7-10.

To a suspension of sodium hydride (0.8 g of a 50% dispersion in mineral oil) in dry Dimethylformamide was added in small portions to 4 g of 2-phenylindole. After the development of hydrogen had ceased, 2.8 g of 4-nitrofluorobenzene were added. The reaction mixture was left at room temperature for 2 days stirred and then poured onto ice. The deposited solid precipitate was filtered off and extracted from acetic acid recrystallized. 3.2 g of reaction product with a melting point of 115 to 125 ° C. were obtained receive. The reaction product was purified by chromatography using neutral aluminum oxide. By eluting with a mixture of ligioin and chloroform in the ratio 9 :! were 2.5 g of a solid yellow body. After recrystallization from ethanol, 2.1 g of reaction product, corresponding to 33% of theory, with a Melting point of 138 to 140 ° C obtained.

NO,

, o Analysis for C _2n Hi ₄ N ₂ O ₂ :

Calculated ... C 76.4. H 4.5. N 8.9:
found ... C 76.4. 114.6. N 8.7.

The implementation was repeated using is the following amounts of reactants:

2-t'henylindole 40 g

Sodium hydride (dispersion) 8 g

4-nitrofluorobenzene 35 g

The reaction mixture was left to stand at 40 ° C. over Nachi and then poured into ice water. the ". gummy precipitate obtained by decanting the aqueous layer was heated with 200 ml of ethano and filtered. After one-time recrystallization 36 g of reaction product with a melting point of 136 to 138 ° C. were obtained from acetic acid. The reaction product was found to be sufficiently pure for further conversion.

C. 1- (4-Nitrophenyl) -2-phenylindole-3-carboxaldehyde

5 g of phosphoryl chloride became 150 m at OC given dry dimethylformamide. Then 9 g of 1- (4-nitrophenyl) -2-phenylindoi were added, whereupon the reaction mixture was heated to 55 to 60 "C for 75 minutes. The mixture was then heated poured onto ice and made basic with 100 ml of a 10% sodium hydroxide solution, whereupon si < Was heated to 90 ° C for 5 minutes. After quenching, the precipitated reaction product filtered off and recrystallized from acetic acid. You yield of aldehyde with a melting point of voi 241 to 242 ° C. was 8 g, corresponding to 65% of theory.

Analysis for C ₂₁ H ₁₄ N ₂ O ₃ :

Calculated ... C 73.7. H 4.1, N 8.2;
Found ... C 73.6, H 4.0, N 8.4.

2046

D. I-p-Acctamido ^ -phenylindole

I · '. l-p-nitrophenyl-S-nilro ^ -phcnylindole

V.

'ν

NO,

NHCOCH.,

NO ₂

A suspension of 45 g of slannochloride dihydrate in 75 ml of acetic acid was treated with gaseous HCl until it became homogeneous. Ig lp-nitrophenyl-2-phcnylindole was dissolved in 80 ml of the resulting solution with heating. The yellow color disappeared. After 12 hours the mixture was poured into a 20% potassium hydroxide solution. The solution was then extracted with ether. The crude amine isolated by concentrating the ether extract was heated on the steam bath for 2 hours with 50 ml of acetic anhydride. The reaction mixture was then ^{poured onto (:} .is. After several hours, 8.5 g of reaction product were filtered off and recrystallized from methanol. The melting point of the pure compound hg at 201 ° C.

Analysis for C
Calculated
found

C 81.0. H 5.6. N 8.6;
C 81.2. H 5.9. N 8.6.

A solution of 3.14 g of lp-nitrophen / l-2-phcnylindole in 20 ml of 95% strength sulfuric acid was cooled to −2 ° C. and a solution of 0.85 g of sodium nitrate in 10 ml of 95% strength sulfuric acid was added dropwise. After stirring for 30 minutes, the mixture was ^{poured onto L:} is. The reaction product was filtered off and crystallized from acetic acid. The yield was 2.8 g. The melting point was 238 to 240 C.

25 analysis for C ₂₁ , 111 , N ₁ O ₄ : I 3.7. N I 1.7: Calculated . . . C. 66.9. I. I 3.8. N I 1.8. Found . . . C. 67.0. I.

C .. I-

P-Nitrophcnvl-5 ~ nitro-2-ph '; nvlindole
3-carho \ aldehvd

CHO

NO,

E. l-p-Acetamidophenyl-2-phenylindole-3-carboxaldechvd

C ₁ . H ₅

CHO

^x N

NHCOCH ₁

~ .lg of lp-acetamido-2-phenylindole in 30 ml of dimethylformamide were added at 0 ° C. to a mixture of 3.6 g of phosphoryl chloride in 40 ml of dimethylformamide. The reaction mixture was stirred at room temperature for 3 hours and then poured onto F.is. The resulting solution was basified by the addition of 10% sodium hydroxide and then heated on the steam bath for 10 minutes. The reaction product was filtered off and then recrystallized from ethanol. The yield hctrue 6 ü corresponding to "S ' ¹ ". The melting point was 246 to 24SC.

An.iKse for C _; ..H, _S N _; O,:

Calculate! . . C "SO H 5.1.
Found . . C ". <\ 11 5.2.

NO,

^{1.44 g of IP-N} : 'trophenyl-5-nitro-2-phenylindole were added to a mixture of 1 g of phosphorus chloride and 20 ml of dimethylformamide. The solution was heated to 70 ° C. for 2 hours, allowed to cool with 5 ml of 10% sodium hydroxide solution and heated on the steam bath for 10 minutes. The precipitated reaction product was filtered off from the resulting solution. After crystallization from acetic acid, the reaction product was *. in a yield of 1.1 g. The melting point was 205 C.

Analysis for C _{; i} H ,, N, O ₅ :

Calculated ... C 65.1. H 3.4. N

Found . . . C 65.4. H 3.t \ N

Claims (5)

Patent claims: 1. Direktpositive, an Indolmothm.-v.ininfarbsioff and optionally a 1 .irhkuppler containing, photographic silver halide emulsion, d a d u r c h g e k e η η ζ e 1 c h net. d.ilJ> it ? 046 as the cyanine dye, one of the formula ₁ = L ₂ -C NR ₂ C XS contains, in which: L ₁ , L ₂ each represent an optionally substituted methine radical, R an optionally substituted alkyl, alkenyl or aryl radical, R ₃ and R ₃ optionally substituted aryl radicals, R ₄ a hydrogen or halogen atom or an alkyl, Alkoxy, aryloxy or nitro radical, η = 1 or 2, Z the atoms required to complete a conventional desensitizing, 5- or ole-membered, heterocyclic ring and X an acid anion customary for cyanine dyes. 2. Direct positive emulsion according to claim 1, characterized in that it is a cyanine dye of the formula given, in which the desensitizing, heterocyclic ring contains a nitro radical or a 3,3-dialkyl-3H-pyrrolo [2,3-b] pyridine, Imidazo [4,5-b] quinoxaline, nitrobenzothiazole, nitrobenzoxazole, nitrobenzoselenazole or 3,3-dialkyl-3 H -nitroindole ring. 3. Direct positive emulsion according to claim 1, characterized in that it contains a cyanine dye of the formula indicated in which the 1,2-di2rylindole ring from a 1- (nitroaryl) -2-arylindole ring consists. 4. Direct positive emulsion according to claim 1, characterized in that the silver halide grains of the emulsion are obscured, preferably by a reducing compound and a gold compound. 5. Direct positive emulsion according to claim 1, characterized in that it is used as a cyanine dye one 1,3-diethyl-1 ', 2'-diphenylimidazo [4,5-b] - quinoxalino-S'-indolocarbocyanine salt, 1,2-diphenyl-3'-ethyl-o'-nitroindolothia- carbocyanine salt,
6-chloro-1,1 ', 2 \ 3'-tetraphenylimidazo [4,5-b> quinoxalino-3-indolocarbocyaniralz, 1, S ^ -trimethyl-S-nitro-1 ', 2'-diphenylindo- 3 '-indolocarbocyanine salt, U-diphenyl-r ^' - triraethylO-indolo- 3 H-pyrrolo [2,3-b] pyridocarbocyanine salt, 1,3-diethyI-1 '- (4-nitrophcnyl) -2'-phenylimidazo [4,5-b] quinoxalino-3'-indolo- carbocyaninialz,
3'-ethyl-6'-nitro-l- (4-nitrophenyl) -2-phenyl- 3-indolothiacarbocyanine salt, 1 ', 3', 3 '-Trimethy 1-1 - (4-nitropheny l> -2-pheny 1-3-indolo-3H-pyrrolo [2,3-b] pyridocarbo- cyanine salt or a
1,3,3-trimethyl-5-nitro-l '- (4-nitrophenyl) - Contains 2'-phenylindo-3'-indolocarbocyanine salt. 109 687/312