DE2233430B2 - Process for the preparation of 3-hydroxy-bromoquinophthalones - Google Patents

Description

(Br) _n

in 10- to
brominated.

75% dilute sulfuric acid. If necessary, the bromination in dilute sulfuric acid of the specified type or a catalyst, ζ. B. iodine, add, in general However, the sulfuric acid itself acts as a catalyst, so that it also acts as a conversion medium and Catalyst is used

The reaction takes place at temperatures of approximately 20 ^° C. up to the boiling point, which can be increased by pressure. The reactions at about 40 to 110 ⁰ C are preferably made.

The German Offenlegungsschrift 16 70880 describes the monobromination of 3'-hydroxyquinophthalone in 80 to 100% sulfuric acid at 20 to 40 ° C known.

Under the given conditions it is not possible to introduce more than one bromine atom to reach.

Furthermore, it is bound to the very narrow temperature range because increasingly done in about 80% sulfuric acid at temperatures above 4O ⁰ C a rearrangement of quinophthalones to colorless compounds.

Surprisingly, it enables the use of dilute 10 to 75% sulfuric acid, even more to introduce bromine as an atom, and it is still possible to start the reaction by increasing the temperature to accelerate, d. H. to shorten the response time significantly.

Since the previously known methods of bromination require relatively harsh conditions, it was not foresee that the comparatively mild conditions of the process according to the invention the introduction allow one or two bromine atoms.

Information about parts and percentages, unless otherwise stated, is based on weight.

example 1

The invention relates to a process for the preparation of compounds of the formula I.

in which η denotes 0 or 1, by bromination of 3'-hydroxyquinophthalones of the formula II

(Br) _n (II)

289 parts of 3'-hydroxyquinophthalone are introduced into 6000 parts of 20% strength sulfuric acid. the 10 parts of iodine are added to the suspension and the mixture is heated to 100.degree. Now one drips with stirring within 165 parts of bromine under the surface of the liquid for 2 hours. After that, the dye becomes still warm Aspirated and washed neutral with warm water. After drying, 367 parts are obtained 3'-Hydroxy-4'-bromo-quinophthalone with a bromine - content of 22.0%.

B e i s ρ i e 1 2

289 parts of 3'-hydroxy-quinophthalone are dissolved in 3000 parts of 96% strength sulfuric acid at room temperature solved. 1800 parts of water are added dropwise in such a way that the temperature rises to 60.degree. Of the The dye precipitates in a fine suspension. It is mixed with 6 parts of iodine and dripped within 165 parts of bromine under the surface of the liquid for 2 hours with stirring. Then you give 2000 parts Water, sucks off and washes neutral. After drying, 366 parts of 3'-hydroxy-4'-bromoquinophthalone are obtained with a bromine content of 21.9%.

in 10 to 75%, preferably 20 to 70%, dilute sulfuric acid.

Example 3

289 parts S'-hydroxy-chinophtlialon are dissolved at 20 to 30 ⁰ C in 3000 parts of 90% sulfuric acid. Are added dropwise 600 parts of water and can thereby the temperature to 6O ⁰ C increase. The suspen-

sion is now mixed with 12 parts of iodine and by adding dropwise 300 parts of bromine within 4 hours brominated. Then you dilute with 2400 parts of water and work as described in Example 1, on. 421 parts of brominated 3'-hydroxyquinophthalone with a bromine content of 31.7% are obtained.

Example 4

To a solution of 2S9 parts! '- Hydroxy- ίο quinophthalone in 2500 parts of 96% sulfuric acid is added dropwise with external cooling 700 parts of water, whereby the product precipitates in fine distribution. This suspension is at room temperature within a solution of 10 parts of iodine in rs 165 parts of bromine was added dropwise over a period of 4 hours. Then you put more 2000 parts of water and works as described in Example 1 on. 36 J parts of 3'-hydroxy-4'-bromo-quinophthalone are obtained with a bromine content of 21.2%.

Example 5

368 parts of 3'-hydroxy-6'-b.Om-quinophthalone are dissolved in 3120 parts of 96% strength sulfuric acid. The colorant is finely precipitated by the dropwise addition of 2880 parts of water and the suspension stirred at 8O ⁰ C. At this temperature, 175 parts of bromine are allowed to run under the surface of the liquid over the course of 2 hours, then stirred for a further 15 minutes and diluted with 1500 parts of water. After working up as in Example 1, 440 parts of 3'-hydroxy-4 ', 6'-uibromo-quinophthalone with a bromine content of 37.3% are obtained.

Example 6

35

368 parts of 3'-hydroxy-4-bromo-quinophthalone are introduced into 2330 parts of 96% strength sulfuric acid and the mixture is stirred until the dye has completely dissolved. The concentration of the sulfuric acid is then reduced to about 40% by gradually adding 3270 parts of water, the finely divided dye precipitating out. 8 parts of iodine are added and 10 parts of bromine are allowed to run under the surface of the liquid ^{at 90 ° C. over a period of 2 hours while stirring.} After a further 10 minutes, the mixture is diluted with 1000 parts of water and worked up as described in Example 1. 429 parts of 3'-hydroxy-4,4'-dibromoquinophthalone with a bromine content of 36.5% are obtained.

Example 7

368 parts of 3'-hydroxy-4'-bromo-quinophthalone are dissolved in 2920 parts of 96% strength sulfuric acid. The dye is precipitated again by the dropwise addition of 1080 parts of water and the suspension is ^{stirred at 105 °} C. After addition of 12 parts of iodine, 180 parts of bromine are added dropwise under the surface of the liquid over the course of 3 hours. The mixture is stirred for a further hour at 105 ^° C. and then 2500 parts of water are added. After working up as in Example 1, 443 parts of 3'-hydroxy-4 ', X-dibromo-quinophthalone with a bromine content of 37.0% are obtained.

Example 8

One by dissolving 289 parts of 3'-hydroxyquinophthalone in 2200 parts of 96% sulfuric acid and reprecipitation with 4800 parts of water is placed in an enamel kettle of 10 000 parts of volume filled. 5 parts of iodine and 165 parts of bromine are added all at once and lock the kettle. The mixture is stirred for 1 hour at 110 ° C., a slight excess pressure of less than 1 atm. Then the boiler is depressurized and the reaction product on a stoneware suction filter pulled the trigger. After washing with water and drying, 365 parts of 3'-hydroxy-4'-bromo-quinophthalone are obtained with a bromine content of 21.6%.

Claims (1)

Claim: Process for the preparation of 3'-hydroxybromoquinophthalones of the formula where O or 1 means, characterized that one 3'-hydroxyquinophthalones of the formula