DE1035660B - Process for the preparation of color developing agents - Google Patents

Description

GERMAN

The invention relates to the production of color developer substances, the z. B. are suitable for the execution of photographic transfer processes, after which colored direct positives after the diffusion transfer process can be produced.

According to the invention, color developing agents of the formula

R2_n = N - R ³ - C - NH- (lower alkyl) «- D '"

in which D 'is a developer unit, R ^{2 is} a substituted or unsubstituted aryl group, R ^{3 is} an aryl group substituted by OH in the o-position to the carboxamido group and preferably a naphthyl group and η = 0 or 1. D 'is an organic radical which is substituted in such a way that, in a known manner, it has properties which develop in relation to exposed silver halide. According to the invention, these compounds are ^{prepared by coupling a diazonium ao} derivative of the aryl group R ² with a compound of the following formula:
O

Method of manufacture
of color developing agents

Applicant:

International Polaroid Corporation,
Jersey, NJ (V. St. A.)

Representative:

Dr.-Ing. H. Ruschke, Berlin-Friedenau, Lauterstr. 37,

and Dipl.-Ing. K. Grentzenberg, Munich 27,

Patent attorneys

Claimed priority:
V. St. v. America March 9, 1954

Milton Green, Newton Highlands, Mass.,
and Howard Garnder Rogers, Weston, Mass.

(V. St. A.),
have been named as inventors

R ³ - C - NH - (lower alkyl) »- D '

Color developing agents of this type can, for. B. be prepared by suitable diazonium coupling, as explained in the following example.

example

A solution of 0.38 g of 2,5-dimethoxyaniline in 1.2 ecm 6 η-hydrochloric acid is cooled to 0 ° C. and diazotized by adding 0.18 g of sodium nitrite in 0.5 g of water. The diazotized product is then slowly added at 5 ° C. to 1 g of a monobenzoate of 2-oxy-N- (2 ', 5'-dioxyphenyl) -3-naphthamide, which is dissolved in 50 ecm of ethanol, 25 ecm of acetone and 50 drops of pyridine is added. After adding 20 drops of 25% sodium carbonate, the solution is stirred for 30 minutes, a precipitate being formed. The precipitate is separated and purified by dissolving in 20 cc of 50 ° / ₀ hydrolyzed aqueous ethanol and adding 4 g of sodium hydroxide in 6 cc of water. The mixture is left to stand in vacuo for 1 hour and then filtered rapidly. The filtrate is acidified and cooled, whereupon 1 g of a compound of the following formula precipitates:

.Λ.

-OH

OCH ₃
OH

(I)

OH

809 580/586

Claims (4)

An example of another color developing agent which can be prepared in the same manner as described above is OC2H6 0 N = N-OC2H5-OH-C-NH- <^ -NH-C- <r OH (Π) OH containing substituents than those which cause a silver halide developing property if these substituents do not destroy the silver halide developing effect. Examples of such substituents are alkyl, oxy, amino, halogen, etc. Attention should be paid to e.g. B. the use of toluhydroquinonyl or aminohydroquinonyl groups. The terms alkyl, aryl, amino, etc. mean both unsubstituted and substituted groups. In the same way, sulfo- or carboxyl also mean salts of acids such as sodium sulfonate. In certain cases it can be useful to protect the oxy or amino groups of the radical D 'during the synthesis of the color developer substance by suitable acylation. These protecting groups can be removed by hydrolysis before use. Here, too, D 'is an organic radical which bears substituents, as a result of which the radical has properties which develop in relation to silver halide. In some of the above explanations one can think of the developing residue D 'as derived from the hydroquinone, i.e. H. D 'consists of the hydroquinonyl group OH OH. There are various other organic radicals which contain substituents which give them silver halide developing properties, such as: 3,4-dioxyphenyl; 1-oxy-4-aminophenyl; l-oxy-4-methylaminophenyl; 1,2,3-trioxyphenyl and 1-oxy-2-aminonaphthyl. These examples of the evolving groups are illustrative only and other substituents may be used which will function as well. In a preferred embodiment, D 'contains an aryl nucleus, e.g. B. a benzene or naphthalene nucleus. If D 'contains a benzene nucleus, the silver halide-developing property can be brought about in a known manner by amino, alkylamino and / or oxy groups arranged in the o- or p-position to one another. For the chemical constitution of the silver halide developing groups, reference is made to The Theory of the Photographic Process, C.E.K. Mees (1942), The MacmiUan Co., New York, N.Y., p. 342 ff. Of course, D 'can also have other sub-Pa τ ι: ν τ λ ns ι * κ rc mc: 1. Process for the preparation of color developing agents of the general formula R ² - N = N - R ³ - C - NH - (lower alkyl) «- D ' in which D 'is an organic radical which is substituted in such a way that it has a developing effect on exposed silver halide, R ^{2 is} a substituted or unsubstituted aryl group, R ^{3 is} an aryl group substituted by an oxy group in o-position to the carboxyamido group and preferably one Naphthyl group and η = O or 1, characterized in that a diazonium derivative of the aryl group R ² with a compound of the general formula R ³ - C - NH - (lower alkyl) «- D ' is coupled. 2. The method according to claim 1, characterized in that a hydroquinonyl group is used for D ' will. 3. The method according to claim 1 or 2, characterized in that diazotized dimethoxyaniline coupled with 2-oxy-N- (2 ', 5'-dioxyphenyl) -3-naphthamide and the product worked up in the usual way will. 4. The method according to claim 1 or 2, characterized in that diazotized 2,5-diethoxy-4-benzamidoaniline with 2-oxy-N- (2 ', 5'-dioxyphenyl) -3-naphthamide is coupled. θ & 09 580/5 & 6 7.5 p