DE2313030C3 - Process for the recrystallization of 3-aryl-7- (1,23-triazol-2-yl) coumarins and compounds of this type in the β-modification - Google Patents

Description

R is a hydrogen atom or an aliphatic or aromatic radical and

Ar is an aromatic carbocyclic or heterocyclic radical

(H)

(III)

in the /! modification, characterized by the J values in the X-ray diffraction diagram: 21.55 Ä, 5.98 Ä, 3.60 Ä, 3.22 A.

6. A method for producing the compound of claim 5 in the /! Modification, characterized in that that one dissolves the α-modification of the compound in sulfuric acid and cools the solution.

7. Use of the compound according to claim 5 as an optical brightener for organic materials.

The invention relates to a process for the recrystallization of coumarin compounds in general Formula I.

10

15th

20th

means,

characterized in that the compounds are dissolved in sulfuric acid and allowed to crystallize out by cooling.
2. The compound of formula II

30th

in the /! modification, characterized by the cZ values in the X-ray diffraction diagram: 14.98 Ä, '7.56AASSA, 3.45 A.

3. A process for the preparation of the compound of claim 2 in the /! Modification, characterized in that that one dissolves the α-modification of the compound in sulfuric acid and cools the solution.

4. Use of the compound according to claim 2 as an optical brightener for organic materials.

5. The compound of formula III

faO

65

wherein

R is a hydrogen atom or an aliphatic or aromatic radical and

Ar is an aromatic carbocyclic or heterocyclic radical

mean.

Preferred compounds are those in which R for Ci-Q-alkyl or hydrogen and Ar for optionally substituted phenyl, pyrazolyl, 1,2,4-triazolyl and Imidazolyl stands.

The compounds of general formula I, their preparation and use as lightening agents are known, e.g. from DE-OS 16 95 817, 15 94 845 and 16 94 362. However, according to the previously described process in dci cyclization of the precursors to the triazole always products that are colored by By-products which give the crystal a yellow-brownish color Give color, as is correctly described in DE-OS 16 95 817, are contaminated. By Recrystallization from organic solvents removes these impurities, which are the coloristic Significantly reduce the effect, only partially eliminate it.

It has now been found that highly pure preparations of the brighteners of the general formula I. obtained when crude compounds of the general formula I are dissolved in hot sulfuric acid and passed through Allow to cool again to crystallize out. The compounds of general formula I in recovered high purity form without lowering the yield.

The optimal concentration of sulfuric acid depends on the structure of the respective compound and fluctuates within wide limits.

When recrystallizing the compounds of the general Formula I in hot sulfuric acid generally undergoes a modification conversion. the new /! modifications form with the by-products no more mixed crystals and are therefore obtained in pure form.

The /! Modifications are due to a crystal habit marked, which delivers a good pourable product. The color of the crystals of the /! Modification is greener, the melting point lower than with the α-modification.

The /! Modifications can be restored by simply dissolving them from an organic solvent transfer into the original ot-form, which can now be obtained in a highly pure form. The /! Modifications can also be used as whitening agents themselves.

The highly pure preparations of the /! Form and the "modifications purified by them give rise to organic Materials, especially synthetic fibers, brilliant and very strong lightening.

By crystallization of the ß-form from dioxane can

one sometimes even deeper melting j> -modifications obtain.

The invention also relates to the modification of 3-phenyl-7- (4-phenyl-5-methyll, 2,3-triazol-2-yl) coumarin (formula II), characterized by the rf values in the X-ray diffraction diagram: 14.98 Å, 7.56 Å, 4.58 Å, 3.45 Å, the ^ -modification of 3- (4-chloropyrazolyl) -7- (4-phenyl-5-methyl-1,2 , 3-triazol-2-yl) coumarin (formula III), characterized by the d values in the X-ray diffraction diagram: 21.55 Å, 5.98 Å, 3.60 Å, 3.22 Å, the respective process cm their Manufactured by dissolving the known crude α-modification in sulfuric acid and cooling and using it to lighten organic materials, especially synthetic fibers.

For the product with the Summenfermel 024H
and the molecular weight of 379, the following analysis values were determined:

5 -

f / -Wcrle [Al
α JS

Intensities α β

14.98
13.0
6.56
3.75

14.98
7.46
4.58
3.45

14.98
7.20
3.52
3.24

100

78

100

57

52

The ^ modification of the compound of formula II was further recrystallized from glycol monoethyl ether. The Debye-Scherrer diagram shows the identity with the «modification obtained by dissolving from toluene has been received.

65

Calculated Found ^ Modification /-Modification 76.1
75.8 C. 76.05 76.0
76.2 11.6
11.4 H 11.09 11.1
11.2

example 1

400 ml 83% sulfuric acid (d = 1,760 ²⁰⁾ are placed in a provided with a stirrer Bechcrglas and heated to 100 ⁰ C. During the heating, 100 g of crude 3-PhenyI-7- (4-phenyl-5-methyl-l, 2,3-triazol-2-yl) -coumarin (fabrication warc - formula II), which has a brown-black coloration of the The contents of the cup go into 2 ^r > solution. The mixture is kept at this temperature for 30 minutes and stirred while it is cold. At about 70 ⁰ C begins the deposition of the ^ modification, which is complete after reaching room temperature. It is filtered off, washed first with 50 ml of cold 83% sulfuric acid, then with 500 ml of water. The suction cake, which still reacts acidic, is now washed with 1000 ml of water containing 50 ml of concentrated ammonia solution until the discharge reacts alkaline. It is then washed with pure water until the effluent reacts neutral. The light green j ^r> product is dried, it dissolves in Glykolmonomcthyläther on clear and melts at 149-! 50 ⁰ C. The melt solidifies immediately, and then finally to melt at 161 -162 ° C. The pure «modification is obtained by dissolving from toluene (1: 5).

Conversion to the y-modification

100 g of the / J-modification of 3-phenyl-7- (4-phenyl-5- 4 ^r > niethyl-1,2,3-triazol-2-yl) -coumarin (formula II) are dissolved in 450 ml of dioxane , from which 91 g of pale yellow crystals with a melting point of 142-143 ° C crystallize on cooling. After evaluating the X-ray diffraction diagrams with the help of the Bragg equation, the three modifications give the following d values:

The «- and the / ^ - modifications were 6% in water dispersed with the help of a commercially available dispersant. The «modification became very unmixed strong, hence the dispersion stability was insufficient. With the ^ modification there was hardly any segregation, the Dispersion stability was therefore satisfactory.

Example 2

32.5 g of 3-phenyl-7- (4-phenyl-1,2,3-triazol-2-yl) -coumarin are dissolved in 200 ml of 85% sulfuric acid (d ²⁰ = 1.780), pale green crystals separate on cooling the ^ modification, which are worked up as described in Example 1. 28 g of crystals are obtained, the X-ray diffraction diagrams of which give the following cZ values:

f / value Jl intensity JS a 18.4 a 43 17.33 6.0 48 84 5.91 4.67 83 37 3.55 3.50 100 100 3.30 46

100 63

37 w) 28

Example 3

20 g of manufactured goods of 3- (4-chloropyrazolyl) -7- (4-phenyl-5-methy! -1,2,3-triazo! -2-yl) -coumarin (formula III) are dissolved in 150 ml of sulfuric acid of density d = 1.670 dissolved hot. On cooling, 15 g of crystals of the jS modification with a melting point of 225-228 ° C. separate out and are worked up as described in Example 1. Furthermore, the modification ^ (239-240 ⁰ mp. C) was converted by redissolution of chlorobenzene in the "modification. The evaluation of the X-ray diffraction diagram provided the values:

r / - \ Vert

intensity

Ji

21.55
5.98
3.60
3.22

67

49

73

100

5 6

The following analysis values were determined:

Calculated Found Found

/ -Modification ff-modification

C 60.7

Cl 8.5

N 16.9

60.6
60.3 61.7
61.8 8.4
8.4 8.7
8.8 16.8
16.9 17.5
17.7

Claims (1)

Patent claims: 1. Process for the crystallization of 3-aryl-7- (1,2,3-triazol-2-yl) -coumarins the general formula (D wherein