DE621404C - Process for the production of intermediates for dyes of the polymethine series - Google Patents

Description

Process for the preparation of intermediates for dyes the Polymethine Series The invention relates to a process for the production of intermediates for dyes of the polyrmethine series. It was found that diarylformamidines with heterocyclic nitrogen compounds, the reactive methyl or methylene groups and can either be in the form of ammonium salts or their bases, react, and there & one to the intermediate products of the dyes of the polymethine series can get.

For example, 2: 3: 3 trimethylindolene iodine methylate is used with diphenylformamidine treated by taking the components either on their own or in a suitable Solvents, e.g. B. acetic anhydride heated. One obtains in this way if the action between the components takes place in the ratio of i: i that desired intermediate. The procedure is general to heterocyclic ammonium salts applicable to the reactive methyl groups, or to the corresponding pseudobases, which contain reactive methylene groups.

Corresponding products are also obtained if you z. B. the halomethylates or ethylates of 2- or 4-methylquinoline, 2-methylbenzoxazole or 2-methylbenzthiazole or the corresponding pseudobases are used. You can do the procedure sometimes with The advantage of changing a salt of the diarylformamidine together with the pseudobases used. It seems necessary that the acid is present when the pseudobase is applied an acid generating solvent such as acetic anhydride may suffice.

The intermediate compounds formed from equimolecular amounts of the components seem, when using diphenylformamidine, for example, aniline vinyl compounds of the heterocyclic salt. If acetic anhydride is used as a solvent, the acetyl derivative of this aniline vinyl compound is obtained in this way. Submit this Acetyl derivative of a suitable hydrolytic treatment, for example by heating with concentrated hydrochloric acid, the acetyl group is split off. If you i: 3: 3-trimethylmethyleneindoline-simply heated with diphenylformamidine chloride, see above the corresponding 3: 3-dimethyl-2-anilinevinylindolenine chloromethylate is obtained right away. You can also, for example, a molecular amount i : 3: 3-: trimethylmethyleneindoline to a molecular amount of free diarylforinamidine; Dissolved in hot acetic anhydride, leave to act or to a molecular level of diarylformamidine chloride alone or in acetic anhydride or in pyridine or dissolved in a neutral solvent, or you can use a molecular amount of the pseudobase and an equivalent amount of acid, preferably mineral acid, or a molecular amount of the corresponding halide with a molecular amount of diarylformamidine heat, or you can have a molecular amount of the heterocyclic salt: with one Molecular amount of diarylformamidine salt in the presence of a molecular amount of sodium acetate let react.

The method according to the invention offers over the known modes of operation for the production of polymethine dyes the advantage that it provides intermediate products, from which are formed by condensation with suitable heterocyclic nitrogen compounds gain asymmetrical dyes of the polymethine series as new products. The diarylformaimidines used are easily available because Diphenylformami: din can be prepared for example by heating aniline and formic acid. The aniline can be regained. In addition, the diphenylformamidines are more general Applicability.

The invention is illustrated by the following examples. the Parts are parts by weight.

Example i 6 parts 2: 3: 3-Trimethylindoleninjodmethylat and q. Parts Diphenylformamidine are mixed with so parts of acetic anhydride and the mixture boiled on the reflux condenser for 40 minutes. The new compound separates as it cools down as a crystal mass, which is filtered off and washed with acetic anhydride will. This product is the acetyl derivative of the product of Example 2. It has a melting point of 260 ° C, at which it decomposes.

Example 2 The product from Example i is dissolved in hot concentrated hydrochloric acid. A new crystalline substance is excreted almost immediately. When the separation is complete, the suspension is cooled and filtered. When recrystallized from water or dilute alcohol, the body shows a melting point of 243 to 2q.4, ° C. The compound likely has the formula below: Example 3 3o parts 2: 3: 3-trimethylindolene iodine methylate and 20 parts diphenylformamidine are mixed together and heated at 200.degree. The mixture quickly turns into a dark red melt, which is allowed to cool slowly to 120 ° C. 60 parts of alcohol are added and the crystalline product is filtered off, washed with alcohol and recrystallized from water. The product is identical to that of Example 2. A small amount of the dye i: 3: 3: i ': 3': 3'-hexamethylindocarbocyanine iodide can be deposited as a by-product from the alcoholic mother liquors and washing waters.

Example [A solution of 58 parts of i-methylbenzoxazole iodoethylate and q.o parts of diphenylformamidine in 250 parts of acetic anhydride is 20 minutes cooked. The new compound separates on cooling, probably acetanilidovinylbenzoxazole iodoethylate the end. Melting point at 227 ° C with decomposition.

.Example A solution of 90 parts of i-methylbenzthiazole iodoethylate and 66 parts of diphenylformamidine in 500 parts of acetic anhydride is 20 minutes cooked. Upon cooling, a crystalline product separates from the melting point 22g ° C, probably Acetanfdovinylbenzthiazoljodäthylat, from.

Example 6 6o parts of quinaldinjodäthylat and 40 parts of diphenylformamidine are intimately mixed and slowly heated to 180 ° C. The mixture becomes mushy or liquid at first, but later stiffer and firmer. It will be out taken out of the reaction vessel, pulverized, for the purpose of removing the aniline, which occurs as a by-product of the reaction, treated with dilute hydrochloric acid, then washed with water and dried.

Instead of diphenylformamidine, other diarylformamidines, for example pp = dichlorodiphenylformamidine, dip-tolylformamidine, etc., use.

Claims (1)

PATENT CLAIM: Process for the production of intermediate products for Dyes of the polymethine series, characterized in that z moles of a heterocyclic Nitrogen compound with a reactive methyl or methylene group in the form an ammonium salt or the corresponding pseudobase in the presence of an equivalent Amount of acid, preferably # mineral acid, act on x moles of a diarylformamidine leaves.