DE2947525A1 - ALKYL SUBSTITUTED BENZOTHIAZOLYLPHENOLS - Google Patents

Description

T.EDTKE - BüHLING - KlNNE Grupe - Pellmann

Dipl.-Ing. R Group 2947525 Dipl.-Ing. B. Pellmann

Bavariaring 4, Postfach 202403 8000 Munich 2

Tel .: 0 89-539653

Telex: 5-24 845 tipat

cable: Germaniapatent Munich

November 26, 1979 DE 0056 / Docket No. 5604

Uniroyal, Inc.

New York, New York 10020 / USA

Alkyl substituted benzothiazolyl

phenols

The invention relates to alkyl substituted benzothiazolylphenols, specifically to 2- (2-B «; nzothiazolyl) phenols which have alkyl substituents on the phenyl ring.

Of the many hydroxyphenylbenzothiazoles known from the literature or F.er.zothiazolylphenolen two compounds are known which have two alkyl substituents have on the phenyl ring. One of these compounds, 4- (2-benzothiazolyl) -2,6-bis (t-butyl) phenol, is from US Pat German patent 2 COR 414 known. This connection is unsatisfactory in terms of its chelating ability. From the literature are present no other benzothiazolylbis (t-butyl) phenols known.

2- (2-Benzothiazolyl) -6- (t-butyl) -3-methylphenol, another benzothiazolyl dialkylphenol, has ^{been reported in the Journal of Physical Chemistry 7.4, # 26} ' ⁴⁴⁷³ (1970). This compound is not satisfied with its suitability as a fluorescent substance-

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Deutsche Bank (Munich) KIo 51/61 070 Dresdner Bank (Munich) KIo 3939844 Posischeck (Munich! Klo 670-43-804

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putting. Fluorescent compounds are used as optical brightening agents.

With the exception of the two above-mentioned, from German patent specification 2 008 414 and from Journal of Physical Chemistry 7_4, # 26, 4473 (1970) known benzothiazolyldialkylphenols are from the No benzothiazolyldialkylphenols known from literature.

The object of the invention are those alkyl-substituted on the phenyl ring Benzothiazolylphenols, similar to the known benzothiazolyldialkylphenols in terms of ability for chelation or the fluorescence properties

are superior.
15th

This invention is characterized in claim 1 by the alkyl substituted benzothiazolyl phenols solved.

The alkyl-substituted benzothiazolylphenols according to the invention have a tendency to form chelates and have a strong fluorescence capacity.

The preferred compound of the invention is enzothiazolyl) -4,6-bis (t-butyl) pheno has the following structural formula:

2- (2-Benzothiazolyl) -4,6-bis (t-butyl) phenol, which is the

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This compound is an isomer of the compound known from German Patent 2 008 414, which has not yet been reported in the literature.
5

The alkyl-substituted benzothiazolylphenols according to the invention are isolates such as the 4- (2-benzothiazolyl) -2,6-bis (t-butyl) phenol known from German patent 2 008 414 superior in chelating ability. In terms of their suitability as Fluorescent substances are the alkyl-substituted according to the invention Benzothiazolylphenols also from Journal of Physical Chemistry 7_4, # 26, 4473 (1970) known 2- (2-benzothiazolyl) -6- (t-butyl) -3-methylphenol

15 far superior.

There are numerous references relating to the preparation of benzothiazoles of this type. Two of the most relevant references are U.S. Patents 3,669,979 (H. B. Freyermuth) and 3,647,812 (R. F. Smith). The two cited US patents relate to the preparation of benzothiazoles by reacting an o-aminothiophenol with an aromatic acid in the presence of phosphorus trichloride. These processes are used for making the Compounds according to the invention modified accordingly been.

The preparation of the preferred compound of the invention according to the equation

Ho Mooc Jo

_KX:

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is shown in Example 1.

example 1

Production of 2- (2-benzothiazolyl) -4,6-bis- (t-butyl) phenol

451 g (1.8 mol) of 3,5-bis (t-butyl) salicylic acid and 255 g (1.8 mol) of 2-aminothiophenol were dissolved in 1800 ml of toluene. Then, phosphorus trichloride is added dropwise while maintaining a reaction temperature of 55 ⁰ C, 247 g (1.8 mol). When the evolution of HCl had subsided, the solution was refluxed for 4 h at 115 ⁰ C, cooled and removed from a

'5 viscous oil that remained in the flask is decanted. The toluene solution was concentrated to give a viscous oil. The oil was heated and dissolved in isopropyl alcohol. The product crystallized out on cooling. After recrystallization from isopropyl

90
^w alcohol and subsequent whitewash nit cold iso propyl alcohol to obtain pure, pale yellow crystals in an amount of 425 g (yield: 70%; melting point: 112 to 114 ⁰ C). The structure was determined by IR

and confirmed NMR readings.
25th

Elementary analysis:

Calculated for C ₃₁ H ₂₅ NOS: C: 74.31; H: 7.42; N: 4.13 Found: C: 74.30; H: 7.31; N: 4.16

The acid used as the starting compound, 3,5-bis {t-butyl) salicylic acid, is not readily available; however, it can be replaced by the procedure described by WH Meek and CH Fuchsman in J. Chem. and Eng. Data, 14 (3), 388-391 (1969) described method prepared the who. The preparation of this acid is described in Example 2 .

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Example 2

69.0 g (3.0 mol) of metallic sodium was dissolved in 1500 ml of ethanol, and a solution of 206 g (1.0 mol) of 2,4-bis (t-butyl) phenol in 500 ml of ethanol was added as a whole or . added in one serving. 150 g (3.3 mol) of carbon dioxide were bubbled through the solution ^{at 55 ° C.} During the addition, which took 1 hour 45 minutes, the reaction mixture became relatively thick due to the formation of a precipitate.

500 ml of Ν, Ν-dimethylacetamide were added and the solvent was distilled off until a reaction ^{temperature of 180 °} C. had been reached. For best results, the temperature must be carefully monitored and very thorough stirring is required. The temperature of 180 ⁰ C was over a period of 1 h 15 min

^ maintain; periodic removal of solvent was necessary during this time. The mixture was then cooled to 90 ⁰ C. 2500 ml of water was added and the mixture was extracted with three 500 ml portions of toluene. The aqueous layer was acidified with concentrated hydrochloric acid and the resulting oil was taken up in ether. The solution was dried over anhydrous magnesium sulfate. Evaporation of the ether gave a solid as the crude product, which after recrystallization from acetonitrile

melted at 162 to 164 ⁰ C (amount: 144 g, corresponding to a yield of 58%).

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Example 3

The compounds according to the invention given below were essentially applied using " the procedures described in Examples 1 and 2, with the introduction of those corresponding to the various substituents Changes made:

1 2 R. 3 R. 4th R. R_ methyl methyl t-butyl methyl methyl Isopropyl t-butyl Isopropyl ethyl Isopropyl t-butyl t-butyl t-butyl t-butyl H t-butyl ethyl t-butyl t-butyl Isopropyl methyl Isopropyl H Isopropyl Isopropyl t-butyl H t-butyl Isopropyl Isopropyl H Isopropyl

It has been found that the compounds of the invention are capable of forming a complex with metal ions and of removing metal ions from aqueous solution. The compounds of the invention are much more effective in this regard than the closest known compounds.

The ability to chelate has been established with respect to copper ions, which are preferred, however, the procedure can apply to others

ο + px px. px px px ρ + ρ +

Ions like Bi ^{i +} , Be ^ ⁺ , Mg, Ca ^ ⁺ , Sr, Ba ^, Zn _t Cd *,

Al ³⁺ , Ga ³⁺ , In ³⁺ , Tl ³⁺ , Yt ³⁺ , La ³⁺ , Pb ²⁺ , Sb ³⁺ , Cr ³⁺ , B ³⁺ , MoO ₂ ²⁺ , Mn ²⁺ , Fe ³⁺ , Co ²⁺ , Ni ²⁺ , Pd ²⁺ , Ce ³⁺ and_Pr ³⁺ oc may be applicable.

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The metal ions can be removed from very dilute aqueous solutions. There were concentrations of some 8GC ppm applied, but could also do a lot lower concentrations such as 1 ppm or less and higher concentrations (up to 5%) can be used.

A solution of the invention is used for extraction purposes Compound applied in an organic solvent. Almost all solvents can be used which dissolve the compounds according to the invention and are insoluble in water. examples for such solvents are chloroform, carbon tetrachloride, 1,2-dichloroethane, toluene, ether and ethyl acetate.

The concentration of the compounds according to the invention in the solvent is not critical, however the more concentrated solutions appear to be more effective than dilute solutions. Concentrations can be used whose limit values are 0.001 molar solutions

and saturated solutions.

The pH of the solution is somewhat critical and varies depending on what is extracted in the individual case Ion. In the case of copper, one

pH below 4.5 only a very small amount extracted. On the other hand, the copper can be in the form of the hydroxide fail and make extractions difficult if a pH above 5.3 is maintained for any length of time will. The pH can be adjusted using a solution of sodium acetate or small amounts of sulfuric acid can be set.

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The complex of the preferred compound according to the invention with the metal ions is in the organic Solvent formed a dark amber yellow hue. The complex can easily be treated with aqueous acid be split or destroyed. Any strong mineral acid can be used for this purpose. Man found that the complex can be destroyed more effectively by 1 η hydrochloric acid than by 6 η hydrochloric acid.

Example 4 is shown to be the preferred compound of the present invention in terms of removal of copper from aqueous solution is more effective than that mentioned above from the German patent 2 008 414 known compound.

Example 4 Comparison of the extraction of copper

The standard solutions described below were used manufactured:

100 ml of a 0.1 M solution of 2- (2-benzothiazolyl) -4,6-bis (t-butyl) phenol (hereinafter referred to as "A") in chloroform,

100 ml of a 0.1 M solution of 4- (2-benzothiazolyl) -2,6-bis (t-butyl) phenol (hereinafter referred to as "B ^H ) in chloroform and

a solution of 0.2786 g CuBr ₀ in 100 ml

mineralized water.

From 1.0 ml of a 10% solution of sodium acetate and 20.0 ml of the copper described above bromide solution, a solution was made. These

Solution was extracted four times with 20 ml portions of the solution from A. To the aqueous solution became

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a drop of concentrated sulfuric acid is added, whereupon the solution to determine the amount of not extracted copper by atomic absorption analysis was subjected. The combined chloroform extracts were four times with portions of 10 ml of 1 η HCl extracted and the combined aqueous extracts were diluted to 40 ml. This solution became one Subjected to analysis to determine the amount of copper extracted by the solution of A.

A similar experiment was carried out in which instead of using the solution from A with the solution from B was extracted. In this case, emulsions were formed, the phases of which slowly separated. aside from that the chloroform extracts had to be filtered with Celite (trademark) to clarify the solution, whereby the some incomplete recovery of copper is explained. The aqueous copper solutions were analogous Way analyzed.

The following table summarizes the analysis results in relation to the copper found:

Initial CuBr-- ³⁰ solution

Remaining Cu after extraction with A

Remaining Cu after extraction with B Cu extracted with A Cu extracted with B

Cu (ppm) % of the total 35 Theoretically Found lot 56. 72 793 827 30th 755 267 755 421 396 286 396 120

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The experiments described above were used to confirm the reproducibility of the results repeated, whereby the following analytical values were obtained:

Cu (ppm) % of the total Theoretically Found lot 791 750 41 753 310 58 753 436 70 396 279 18th 396 72

Initial CuBr - '0 solution

Remaining Cu after extraction with A

Remaining Cu after extraction with B Cu extracted with A Cu extracted with B

Fluorescence properties

2- (2-benzothiazolyl) phenols are useful as fluorescent compounds are known, while the m- and p-hydroxyl derivatives venig or no fluorescence (J. Phys. Chem. 7_4, 4473 (1970), US-PS 3,647,812 and

nc U.S. Patent 3,669,979). The extent of fluorescence of o-hydroxyl derivatives varies considerably, depending on the additional substituents are on the phenyl ring. Most of the time, the amount of fluorescence of the compounds is reduced by the presence of additional substituents, but in the case of the known compound 2- (2-benzothiazolyl) -6- (t-butyl) -3-methylphenol (hereinafter referred to as "C") a stronger fluorescence observed to a small extent. The fluorescence of A and C was compared. It was found that A fluoresces much more strongly than C. These comparative experiments are explained in more detail in Example 5.

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Example 5

Solutions of Λ and C in methanol with a concentration of 10.0 mg / 1 each were prepared, d. H. a 2.94 10 m solution of A and a 3.37 χ 10 m solution of C. The intensity of the fluorescence these solutions were measured. A fluorescence spectrometer (Perkin-Elmer model 203) used, with a xenon lamp as the light source, two grating monochromators (one for the excitation and one for analysis), a photoelectron multiplier and a micro-ammeter as a display device were applied. Complete spectra were recorded with excitation irradiations of 295 nm at 330 nm.

'- * men, and the intensity of the fluorescence was between 220 and 550 nm registered. The measured values are shown in Tables 1 and 2. As can be seen from these measured values, A fluoresces a lot at all wavelengths

more intense than C.
20th

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Excitation wavelength: 330 nm. Sensitivity 5,

Selector X 1,% 100

Λ on 220 / Intensive 4.1 C. Relation of the on the Kon A to the on the Ratio of 1.5 Analyzer 250 / being- <1 centration-related interests Concentration related Intensities * ■>
1.6 (nm) ι 300 units 1 sity of Intensity of C per (mol / l) * «
1.8
2.2 10 I. 350 A. 59 Ratio of 2.3 360 70 Intensities 2.6 370
380 76
82 per (w / v) 2.6 390 92 -0- 2.9 400 110 -0- 3.0 15th 410 109 1 3.2 420 109 44 3.2 430 102 50 1. 3 3.4 440 91 47
44 '.
1.4 j, ^
3.6 450 76 46 1.6
1.9 -> f "
3.8 460 63 17th ··· WY
2.0 3.9 20th 470 50 47 C- f \ J
2, 3 ^, 1 480 40 44 2. 3 r
4.6 490 31 39 * ·, J
2.5 H, 8 500 25th 33 2.6 6.1 510 20th 27 C- f \ J
2 8 V /, -I
6.3 520 17th 21 cf υ
2.8 10 530 14th 16 C f \ J
"K 0 25th 540 11 12th J, ^u
3.1 550 9 9 3. 3 56Ο 6.5 7th 3.4 5 ~ J r
3.6 4th Ij, 0 2.5 7 '
4.2 2 5.6 30th 1 5.5 <1 ^ ψ ^
Q •

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/ j-effect wavelength: 2 95 nm. Sensitivity 7, Selector X10,% 100.

λ am 220 Intensity / / Relation to the conc aur aie bigwig - Ratio of - Analyzer 250 units / / tration-related intensity tration-related intensity 1.5 Intensities 1.7 (nm) 300 from A to the by C 1.3 per (mol / 1) 1/5 10 310 A. Ratio of 1.2 320 Intensities - 1.2 330 per (w / v) - - 3'IO -0- 1.3 350 -0- If " 15th 360 -0- 53 1.6 1.8 370 -0- 35 1.7 2.0 380 80 59 1.9 2.2 390 44 84 2.0 2.3 400 70 82 2.2 2.5 410 97 70 2.5 2.9 420 99 56 2.5 2.9 20th 430 90 42 2.7 3.1 440 78 32 2.9 3.3 450 65 25th 3.2 3.7 460 54 20th . 3.2 ³ 'I. 470 45 16 3.3 ? '? 480 40 13th 4.6 490 36 11 3.5 4.0 25th 500 32 9 6.0 6.9 510 28 7th 5.0 5.8 520 24 5 - - 530 20th 4th - - 540 16 3 550 13th 2 10 2 on 8th 1 JU 7th 1 6th CX 5 <1 5 <1 4th 3

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Claims (8)

Claims 1, alkyl-substituted benzothiazolylphenols of the general formula 20th 12 3
wherein R, R and R, which can be the same or different, are hydrogen or linear or branched alkyl groups having 1 to 4 carbon atoms and wherein R is either hydrogen or a t-butyl group, where provided that at least two of the groups 12 3 4 R, R and R are alkyl groups when R is hydrogen and that at least one of the groups R, R and R 4th
is an alkyl group when R is a t-butyl group. 2. Benzothiazolylphenols according to claim 1, characterized 1 2 characterized in that at least one of the groups R, R and R is a secondary or tertiary alkyl group. 3. Benzothiazolylphenols according to claim 1 or 2, characterized in that at least one of the groups 1 2 3
R, R and R is a tertiary alkyl group. XI / rs 030023/0807 Deutsche 8ank (Munich) KIo 51/61070 ORIGINAL INSfEClED - 2 - DE 0056 4. Benzothiazolylphenols according to claim 1, characterized 4 indicated that R is hydrogen. 5. benzothiazolylphenols according to claim 4, characterized in that at least two of the groups R, R and R are secondary or tertiary alkyl groups. 6. benzothiazolylphenol according to claim 5, characterized 1 indicated that R and R are t-butyl groups 2 10 and that R is hydrogen. 7. Benzothiazolylphenol according to claim 1 having the formula 2- (2-benzothiazolyl) -4,6-bis (t-butyl) phenol. 15th 8. Use of the alkyl-substituted benzothiazolylphenols according to claim 1 for chelating with metal ions from aqueous solution. 030023/0807