DE1251736B - - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE ^

EDITORIAL

Jflt. Cl.

C 07 c ς

German class: 12 ο -15

Number: 1 251 736

File number: C 29055IV b / 12 ο

Filing date: February 1, 1963

Open date: October 12, 1967

It has been found that alkyl 2,3,4-trichloroanthraquinone-1-carboxylates can be obtained in an elegant manner if you get the Diels-Alder adduct of 5,5-dialkoxy-l, 2,3,4-tetrachlorocyclopentadienes and 1,4-naphthoquinone (formula I) in organic solvents, preferably in an aliphatic one Halogenated hydrocarbons, subjected to the action of chlorine or bromine at elevated temperature and the halogen addition product obtained in this way in an organic solvent which is at least so high boiling like acetic acid, heated. 'The implementation takes place according to the following formula:

CI2 or ΒΓ2

Il

O Cl

The compounds of the formula I to be used as starting materials can be made equimolecular by heating Amounts of a 5,5-dialkoxy, especially 5,5-dimethoxy-1,2,3,4-tetrachlorocyclopentadiene and 1,4-naphthoquinone can be obtained (cf. German Auslegeschrift 1 186 053).

Examples of organic solvents suitable for the present process are aliphatic ones Halogenated hydrocarbons, such as chloroform, carbon tetrachloride, tetrachloroethane, or aliphatic ones Carboxylic acids, such as acetic acid or chlorinated acetic acid, called.

The halogen exposure takes place at an elevated temperature, i. H. at temperatures between 50 ° C and the boiling point of the solvent used. Probably this will be halogen first attached to the isolated double bond of the Diels-Alder adduct, whereupon with ring opening Hydrogen halide and alkyl halide ab manufacturing processes

of 2,3,4-trichloroanthraquinone-

1-carboxylic acid alkyl esters

Applicant:

CIBA Aktiengesellschaft, Basel (Switzerland)
Representative:

Dr.-Ing. Dr. jur. F. Redies,
Dr. rer. nat. Β. Redies, Dr. rer. nat. D. Turk
and Dipl.-Ing. Ch. Gille, patent attorneys,
Düsseldorf-Benrath, Erich-Ollenhauer-Str. 7th

Named as inventor:

Dr. Paul Kniel, Muttenz (Switzerland)

Claimed priority:

Switzerland of February 2, 1962 (1310)

are split and aromatization of the molecule with rearrangement of the ketal group into the carboalkoxy group entry.

If the addition of halogen is carried out in a solvent with a relatively low boiling point, such as chloroform or carbon tetrachloride, the reaction must be completed after its removal in a higher-boiling solvent such as glacial acetic acid.
The 2,3,4-trichloroanthraquinone-1-carboxylic acid esters obtained in good yield and purity can be removed from the reaction mixture by filtration. When carrying out the reaction in distribution agents in which 2,3,4-trichloroanthraquinone-1-carboxylic acid esters are very soluble, such as trichlorobenzene, it is advisable to evaporate the solution to dryness and remove the residue from an appropriate solvent before separating the reaction product recrystallize. Glacial acetic acid is particularly suitable for this.

The 2,3,4-trichloroanthraquinone-1-carboxylic acid ester is obtained by saponification under mild conditions the free 2,3,4-trichloroanthraquinone-1-carboxylic acid. Both the acid and the ester are valuable represent new intermediates that can be used for a wide variety of purposes, such as the Manufacture of vat dyes, disperse dyes or pigments.

709 677/415

Claims (2)

In the following examples, unless otherwise stated, the parts are parts by weight, the percentages are percentages by weight, and the temperatures are given in degrees Celsius. For example 5 50 parts of the adduct of 5,5-dimethoxy-1,2,3,4-tetrachlorocyclopentadiene and 1,4-naphthoquinone are dissolved in 600 parts by volume of hot chloroform. The solution is then allowed to cool to room temperature and 78 parts of bromine are added. In the course of one hour, the mixture is heated to the boiling point and refluxed for 5 hours. The mixture is left to cool for 12 hours while stirring and then evaporated to dryness. The residue is taken up in 320 parts by volume of glacial acetic acid, dissolved while hot and, after a little activated charcoal has been added, boiled for one hour, during which time there is strong elimination of hydrogen halide. The hot solution is filtered to separate the activated carbon. The mixture is then allowed to cool to room temperature, filtered, the filter cake is washed with glacial acetic acid and water and dried. 37 parts, corresponding to 84.6% of theory, of pure 2,3,4-trichloroanthraquinone-1-carboxylic acid methyl ester with a melting point of 194 ° to 195 ° are obtained. C16H7O4Cl3; Calculated C 52.00, H 1.91, Cl 28.78, CH3 4.07%; found C 51.90, H 2.04, Cl 28.76, CH3 4.06%. For characterization, the following reactions are carried out with the methyl 2,3,4-trichloroanthraquinone-1-carboxylate: a) The 2,3,4-trichloroanthraquinone-1-carboxylic acid is obtained by saponification with alcoholic sodium hydroxide solution at room temperature. Yellow glacial acetic acid prisms that melt at 272 to 273.5 ° (uncorrected). Ci5H5O4Cl3; Calculated ... C 50.67, H 1.42, Cl 29.92%; found ... C 50.70, H 1.51, Cl 2.9.93%. When titrating with alkali lye, 99.8% of the amount of alkali calculated on the basis of the molecular weight 355.5 was consumed. b) The 2,3,4-trichloroanthraquinone-1-carboxylic acid can easily be converted with thionyl chloride into the acid chloride, which can be converted into 2,3,4-trichloroanthraquinone-1-carboxamide by reaction with ammonia, which can be converted from glacial acetic acid into pale yellow needles crystallized, which melt at 282 to 282.5 ° (uncorrected). B e 1 s ρ 1 e 1 2 10 parts of the adduct of 5,5-dimethoxy-1,2,3,4-tetrachlorocyclopentadiene and 1,4-naphthoquinone are distributed in 120 parts by volume of glacial acetic acid. A weak stream of chlorine is passed into the suspension and the mixture is heated under reflux until the elimination of hydrogen chloride no longer occurs. The mixture is then allowed to cool to room temperature, the reaction product crystallizing out. It is filtered off, the filter cake is washed with glacial acetic acid and with 736 water and dried. 6.8 parts, corresponding to 78% of theory, of crude 2,3,4-trichloroanthraquinone-1-carboxylic acid methyl ester with a melting point of 175 ° to 183 ° are obtained. The pure compound with a melting point of 195 ° is obtained by recrystallization from glacial acetic acid. Example 3 If 56.6 parts of the adduct of 5,5-di-η-propoxy -1,2,3,4-tetrachlorocyclopentadiene and 1,4-naphthoquinone are used and the rest of the procedure as in Example 1 is used, the result is in a yield of 74.7% of theory, the 2,3,4-trichloroanthraquinone-1-carboxylic acid n-propyl ester with a melting point of 132 ° to 133 °. Recrystallization from glacial acetic acid gives pale yellow needles with a melting point of 133 ° to 133.5 °. Calculated ... Cl 26.8%; found ... Cl 26.6%. For characterization, the propyl ester is converted by saponification into the 2,3,4-trichloroanthraquinone-1-carboxylic acid with a melting point of 272 ° to 273.5 °, which has already been obtained from the methyl ester. Example 4 15 parts of the adduct of 5,5-dimethoxy-1,2,3,4-tetrachlorocyclopentadiene and 1,4-naphthoquinone are dissolved in 150 parts by volume of trichlorobenzene by heating. At 90 °, 9.2 parts by volume of bromine are added dropwise with stirring in one hour. Stirring is then continued at the same temperature. After about an hour, an exothermic reaction occurs with vigorous elimination of hydrogen halide, the temperature rising briefly to 97 °. The batch is kept on the whole at 90 ° for 6 hours, then left to stand overnight at room temperature and then heated to 120 ° for a further 3½ hours. After this time, the elimination of hydrogen halide is complete. The clear yellow solution is evaporated to dryness under reduced pressure and the yellow residue is recrystallized once from glacial acetic acid with the addition of a little chromium trioxide. 10.25 parts, corresponding to 78% of theory, of pure 2,3,4-trichloroanthraquinone-1-carboxylic acid methyl ester with a melting point of 194 to 195 ° are obtained. 1. Procedure for. Production of 2,3,4-trichloroanthraquinone-l-carboxylic acid alkyl esters, characterized in that the Diels-Alder adduct of 5,5-dialkoxy-i, 2,3,4-tetrachlorocyclopentadienes and 1,4-naphthoquinone in organic solvents, preferably in an aliphatic halogenated hydrocarbon, subjected to the action of chlorine or bromine at elevated temperature and that at the same time obtained halogen addition product in an organic solvent which is at least so high boiling like acetic acid, heated. 2. The method according to claim I _i, characterized in that at least 60 parts of bromine are allowed to act on 50 parts of the Diels-Alder adduct.