DE128955C - - Google Patents

Description

IMPERIAL

PATENT OFFICE.

C ₀

In the representation of phenylglycine-ocarboxylic acid a small amount of anthranilic acid and monohaloacetic acid is formed as a by-product, one through two acetic acid residues Anthranilic acid substituted in the amido group, which can be referred to as anthranilodiacetic acid is, and which is evidently the constitution

_{N /} CH ₂ .COOH

^ CH ₂ -COOH COOH

comes to.

It has now been shown that this body is obtained in good yield if one instead of ι molecule 2 molecules of monohaloacetic acid can act on anthranilic acid, or if you have equimolecular amounts of monohaloacetic acid and phenylglycine - ο - carboxylic acid brings into reaction. In both cases it is advantageous to react in the presence to let go of alkali.

The new body, which melts at 21 5 ^0, is easily soluble in hot water, less readily in alcohol and in ether. The solutions show an intense blue fluorescence.

It has now also been shown that this acid is eminently capable of to be transformed into indoxyl compounds with ring formation, which in turn can easily be converted into Indigo resp. Indigo derivatives can be converted. This ring closure lets itself through cause the most varied of condensation agents, and that is obtained depending on the choice of these means and, depending on the working conditions, various intermediate, ducts or various indigo dyes.

So you get by heating the acid in an aqueous solution with alkalis or alkaline earth to an indoxyl derivative, which presumably the constitution

C O OH

C (OH)

and should therefore be referred to as indoxyloacetic acid. The same product can you get when you get sodium acetate, zinc chloride or. Sulfuric acid is used as a condensation agent or if acetic anhydride is used on the salts of the anilodiacetic acid has an effect. In the case of the use of the latter condensation agent arises first acetylindoxyloacetic acid, which z. B. by heating with soda solution in the indoxyloacetic acid can be converted.

The indoxyloacetic acid crystallizes from hot water in yellow, at 165 °, with decomposition melting crystals. Your aqueous solution has an intense green fluorescence.

The reaction in the formation of this indoxyl compound proceeds very probably in such a way that the escape of water between the carboxyl group of the nucleus and one of the two C H ₂ groups of the vinegar

acid residues the indoxyl ring closes and first the indoxyloacetic acid

H _n - COOH

₆ X

C (O H)

forms, which then passes into the indoxyloacetic acid through the escape of carbonic acid.

It is indeed possible to isolate this intermediate product, the indoxyloacetic acid, if one uses the dry salts of anthranilodiacetic acid with caustic alkalis heated at temperatures around 200 ° and the melt in the cold with diluted mineral acids treated.

The Indoxyloessigcarbonsäure thus obtained melts with decomposition at 150 ⁰ and their aqueous solution läfst by simply heating under carbon dioxide elimination smoothly into the Indoxyloessigsäure transform.

The two indoxyl derivatives mentioned can also be weakly oxidized by oxidizing agents alkaline, neutral or acidic solution easily transferred into the corresponding indigo body will.

This crystallizes from hot water, in dark green leaflets, melting with decomposition at 190 ^0th It is easily soluble in alcohol as well as in ether.

If, on the other hand, the dry salts of anthranilodiacetic acid with caustic alkalis, with or without the addition of quick lime, are heated to higher temperatures, the indoxyloacetic acid which is likely to be formed initially splits off the carboxyl of the indole ring as well as that of the residue - CH ₂ - CO ₂ H , with formation of sodium methylindoxyl, and finally the latter is converted into indoxyl itself. Accordingly, when heated to 280 to 300 °, a melt is obtained, the aqueous solution of which can be converted directly into indigo by oxidizing agents, while at temperatures between 200 and 280 ° melts are formed which, on oxidation, yield several indigo derivatives, including dimethyl indigo. The formation of a product which is sparingly soluble in water is also observed, which is probably an indigo or methyl indigomonoacetic acid.

The procedure is illustrated by the following examples:

Example 1.

Presentation of anthranilodiacetic acid.

ι 37 kg of anthranilic acid, igo kg of chloroacetic acid and 165 kg of calcined soda are in 10001 Dissolved water and the solution was heated to 80 ° for 10 hours. By felling with mineral acids the anthranilodiacetic acid is obtained in the form of colorless leaflets.

Example 2.
Preparation of indoxyloacetic acid.

253 kg Anthranilodiessigsäure are dissolved in 500 ⁰ B. 40 kg of sodium hydroxide. It is boiled on the reflux condenser for 10 hours. The solution is then diluted with water and poured into cold sulfuric acid. The indoxyloacetic acid falls in yellow crystals

Example 3.

Representation of the indoxyloacetic acid.

CH ₂ -CO OH

C-C

C (OH).

C ₆ H ^ yC-COOH

319 kg neutral sodium salt of Anthranilodiessigsäure are mixed with 500 kg of potash and the mixture heated for 1 hour at 200 ^0th The cooled melt is powdered and poured into cold, dilute sulfuric acid, the indoxyloacetic acid separating out as a poorly soluble powder that soon turns blue in the air.

As already mentioned above, the indoxyloacetic carboxylic acid obtained can be removed simply by means of it Boil their aqueous solution gently into the indoxyloacetic acid described in Example 2 convict.

Example 4.
Preparation of indigodiacetic acid.

The melt obtained according to Example 2 or 3 is dissolved in 10 cbm of water by introducing it the indigo body is formed by air and separated by adding mineral acid. He colors Wool in an acid bath to blue-green.

Example 5.
Depiction of indigo.

319 kg of the sodium salt of anthranilodiacetic acid are mixed with 500 kg of potash and 300 kg of quick lime. The mixture is then heated ^{to 300 ° for 1 hour.} After cooling, it is dissolved in water and, after filtering off, the indigo is separated off by passing in air.

Example 6.

253 kg of anthranilodiacetic acid or 319 kg of the sodium salt of this acid are used in 1000 kg boiling acetic anhydride entered. With evolution of carbonic acid, the acid goes respectively. the salt in solution. After the evolution of carbonic acid has ended, the excess acetic anhydride is distilled off in vacuo and the Treated residue with water. The acetyl compound which separates out in the process can be dissolved

by heating with soda solution into the indoxyloacetic acid convict.

Example 7.

31g kg of the sodium salt of anthranilodiacetic acid are intimately mixed with 400 kg of zinc chloride. The mixture is heated to 200 to 250 ^{0 for 1 hour.} After cooling, it is dissolved in water and the resulting salt of indoxyloacetic acid is converted into the salt of indigoacetic acid by air.

Claims (1)

Patent claim:
Process for the preparation of indigodiacetic acid and indigo, consisting in that one resp. By the action of haloacetic acid on anthranilic acid. Phenylglycine-o-carboxylic acid generated anthranilodiacetic acid, treated by treatment with the known condensing agents suitable for converting phenylglycine and its derivatives into indoxyl compounds, and oxidized the indigoleucobody obtained.