AT521203A1 - Synthesis of alkylthio-substituted poly (p-phenylene-vinylene) polymers - Google Patents

Abstract

The invention relates to a process for the preparation of 2,5-di (alkylthio) -α, α'-dihalo-p-xylenes of the following formula (3), wherein R and R 'are each independently selected from saturated, linear, branched or cyclic C1 -C20-Aikylresten is selected and X is selected from Cl and Br, comprising the reaction of 1,4-diiodobenzene (1a) to 1,4-di (alkylthio) benzenes (2) and their para-halomethylation by reaction with formaldehyde ( CH2O) in the presence of the corresponding hydrogen halide (HX) to the corresponding 2,5-di (alkylthio) -α, α'-dihalo-p-xylenes (3), where either: i) when R = R ', 1, 4-diiodobenzene (1a) directly with 2 mol of thiol of the formula R-SH to the corresponding 1,4-di (alkylthio) benzene (2) and then to the corresponding 2,5-di (alkylthio) -α, α'-dihalogeno p-xylene (3) is reacted; or ii) when R ≠ R ', 1,4-diiodobenzene (1a) is first reacted with 1 mol of alkyl iodide of formula RI to give the corresponding 4- (alkylthio) iodobenzene (1b), then with 1 mol of thiol of formula R'-SH mixed 1,4-di (alkylthio) benzene (2) and finally reacted with formaldehyde in an analogous manner as above to give the mixed 2,5-di (alkylthio) -α, α'-dihalo-p-xylene (3).

Description

The present invention relates to the production of 2,5-di (alkylthio) -a, a'-dihalogen-xylenes and their use as monomers for the production of alkylthio-substituted poly (p-phenylene-vinylene) polymers.

STATE OF THE ART

Poly (p-phenylene-vinylene) polymers (PPVs) are conjugated backbone polymers that consist of alternating phenylene and vinylene units. These have shaped the field of organic electronics and new applications are already emerging, e.g. Bioimaging and drug delivery that take advantage of the excellent fluorescence properties, low toxicity and biocompatibility of PPVs.

For many applications, substituents are attached to the conjugated PPV main chain. The substituents serve to solubilize the polymers, but are also useful for adjusting electronic, spectral, morphological and self-assembly properties. Alkoxy substituents (häufigsten-PPVs) are most frequently chosen, with 2,5-dialkoxy-substituted PPVs with methoxy and 2-ethylhexyloxy (MEH-PPVs) or methoxy and 3,7-dimethyloctyl (MDMO-PPVs) as the most studied substituents represent substituted PPVs.

MEH-PPV

MDMO-PPV

Recent applications of these two polymers include moisture sensors, thermoelectric devices, wave modulators, memory devices, studies of mixing and crosslinking in OLEDs, light emitting electrochemical / 60

-1 cells, hole transport layers in perovskite solar cells, photodetectors, donor-acceptor systems in micelles and a study on the formation mechanism of PPV nanoparticles. Nanoparticles of dialkoxy-substituted PPVs have recently been used for light-curing composites, charge transfer studies, long-term tumor cell tracking and as bioimaging probes for cell examinations that demonstrate biocompatibility.

Interestingly, despite the diverse uses of Anal-PPVs, dialkylthio-substituted analogues of Ο-PPVs, i.e. S-PPVs, have not been described in the peer-reviewed literature. This is surprising since the simple structure of PPVs means that possible structural variations are very limited and it is known that the replacement of oxygen by the larger sulfur atom is a minor but very effective variation for PPVs due to the expected weaker electron donor properties of the alkylthio substituents can. This effect has already been investigated for other classes of conjugated polymers (see the review by Cui and Wong, Effects of Alkylthio and Alkoxy Side Chains in Polymer Donor Materials for Organic Solar Cells, Macromol. Rapid Comm. 37, 287-302 (2016)).

For S-PPVs, it can be assumed that similar conformation effects as reported for O-PPVs will also play a major role. For the alkylthio-substituted PPVs (Yoon et al., J. Polym. Se. Part A: Polym. Chem. 35, 2253-2258 (1997); Shim et al., Synth. Met. 101, 134 -135 (1999); Hou et al., J. Polym. Sci. Part A: Polym. Chem. 44, 1279-1290 (2006)):

-23/60, each with only one alkylthio substituent on the phenylene units and either none or methoxy as the second substituent, however, an effect similar to that for dialkoxy-substituted O-PPVs was not reported and is also not to be expected.

However, advantageous properties have not only been found for S-PPVs, but also for SO2PPVs, i.e. Dialkylsulfonyl-substituted PPVs, i.e. the oxidation products of S-PPVs, are expected and reported in one case: Hubijar et al. (J. Phys. Chem. B 117, 4442-4448 (2013)) disclose the synthesis of 1,4-dibromo-2,5-di (2-ethylhexylthio) benzene 2, the subsequent oxidation to 1,4-dibromo 2,5-di (2-ethylhexylsulfonyl) benzene 3 and its polymerization to the corresponding SO2-PPV:

Diiodobenzene is first used in the presence of 20 mol% copper (l) iodide and neocuproin, a special chelate complexing agent for Cu (l) ions, and 4 equivalents of K3PO4 in DMF with 2-ethylhexanethiol at 115 ° C for 48 hours for the 1st , 4-Di (2-ethylhexylthio) benzene 1, which is then subjected to para-dihalogenation with Br2 in the presence of I2 in CH2CI2 at room temperature for 3 d to obtain 2. According to Hubijar et al., See above, its oxidation to 3 took place with H2O2 in acetic acid under reflux.

-34 / 60

The polymerization of 3 to di (2-ethylhexyl) -SO2-PPV (SO2EH-PPV) was carried out via a Stille coupling reaction with trans-1,2-bis (tri-n-butylstannyl) ethylene with palladium catalysis with tetrakis (triphenylphosphine) ) palladium (0), Pd (PPhs) 4, in toluene under reflux for 24 h.

This way of obtaining SO2-PPVS by polymerization using a Stille coupling is consequently very complex and costly and, moreover, only provided a relatively low molecular weight SO2-PPV (M _n : 10,600, M _w : 27,800). The usual polymerization method for obtaining PPVs are therefore different variants of the Gilch reaction, especially starting from optionally substituted α, α'-dihalogen-p-xylenes with the elimination of hydrogen halide in the presence of a base, for example potassium tert-butoxide:

For S-PPVs, however, such a polymerization reaction was just as little described in the peer review literature as the synthesis of suitable 2,5-di (alkylthio) -a, a'-dihalogen-p-xylenes. There are two preprints by authors from the same working group (Gutierrez et al., Polymer Preprints 45 (1), 172-173 (2004); and Zepeda et al., PMSE Preprints - Polymerie Materials: Science and Engineering 99, 815- 816 (2008)), in which the same general synthetic route for the preparation of 2,5-di (2-ethylhexylthio) -a, a'-dibromo-p-xylene or 2,5-di (3,7-dimethyloctylthio) - a, a'-dibromo-p-xylene and their polymerization to the corresponding S-PPVs is described. However, both publications were never examined, the reaction conditions for the synthetic route to obtain the monomers are not fully specified in both articles (molar ratios, order of addition and reaction time are missing), and characterizations of the products obtained based on physical data are completely absent.

-45 / 60

The synthesis route from Zepeda et al., See above, for obtaining 2,5-di (3,7 dimethyloctylthio) -a, a'-dibromo-p-xylene is shown below:

That of 2,5-di (2-ethylhexylthio) -a, a'-dibromo-p-xylene from Gutierrez et al., So, is essentially identical, except for the use of 2-ethylhexyl bromide instead of 3.7- Dimethyloctyl bromide as the reagent in the penultimate stage and THF instead of Et2O as the solvent in the last stage.

In any case, even assuming that this reaction scheme actually proceeds as indicated, such a five-step synthesis is very complex and costly, and it is doubtful that the respective product can be obtained in acceptable overall yield - over five steps.

Against this background, the aim of the invention was to develop a new, less complex synthetic route for the preparation of 2,5-di (alkylthio) -a, a'-dihalogen-pxylene monomers as starting products for Gilch polymerization reactions to obtain corresponding alkylthio-substituted S -PPVs or their sulfonyl-substituted oxidation products.

-56 / 60

SUMMARY OF THE INVENTION

The present invention achieves this aim in a first aspect by providing a process for the preparation of 2,5-di (alkylthio) -a, a'-dihalogen-p-xylenes of the formula (3) below,

^s \

R ’(3) wherein R and R 'are each independently selected from saturated, linear, branched or cyclic Ci-C2o-alkyl radicals and

X is selected from CI and Br, comprising the conversion of 1,4-diiodobenzene (1a) to 1,4-di (alkylthio) benzenes (2) and their para-halomethylation by reaction with formaldehyde (CH2O) in the presence of the corresponding hydrogen halide (HX) to the corresponding 2,5-di (alkylthio) -a, a'-dihalogen-p-xylenes (3), either:

i) if R = R ', 1,4-diiodobenzene (1a) directly with 2 mol thiol of the formula R-SH to the corresponding 1,4-di (alkylthio) benzene (2) and then to the corresponding 2,5-di (alkylthio) -a, a'-dihalogen-p-xylene (3) is reacted:

or ii) if R * is R ', 1,4-diiodobenzene (1 a) first with 1 mol of alkyl iodide of the formula R1 to the corresponding 4- (alkylthio) iodobenzene (1b), then with 1 mol of thiol of the formula R'-SH to the mixed 1,4-di (alkylthio) benzene (2) and finally in analog

-67 / 60

Way as above with formaldehyde to the mixed 2,5-di (alkylthio) -a, a'-dihalogen-p-

This new synthesis enables the desired 2,5-di (alkylthio) α, α'-dihalogen-p-xylenes of the formula (3) to be prepared in only two stages for products with identical alkyl radicals R and R 'or three stages for mixed Products, including those with two different alkyl radicals R and R '. The reaction sequence represents a new combination of known individual reactions which, moreover, almost all have been optimized by the inventors, as explained below. The only exception is the reaction from (1a) to (1b), which also in preferred embodiments of the present invention to those known from the literature (Sevez and Pozzo, Dyes Pigments 89, 246-253 (2011)) only for R = CH3 Way is carried out.

This means that the reaction of 1,4-diiodobenzene (1a) to the corresponding 4- (alkylthio) iodobenzene (1b) preferably in a manner known per se with 1 mol of alkyl iodide of the formula R1 in the cold using n-butyllithium (n -BuLi) and elemental sulfur (Se) in a solvent, preferably in diethyl ether:

-78 / 60

However, according to Sevez and Pozzo, see above, the product (1 b) is subsequently not reacted with a thiol as in the present invention, but with a bromothiophene.

The reaction of 1,4-diiodobenzene (1 a) or 4- (alkylthio) iodobenzene (1 b) to give the respective 1,4-di (alkylthio) benzene (2) is carried out in accordance with preferred embodiments of the invention with 2 mol of thiol of the formula R. -SH or 1 mol thiol of the formula R'-SH using copper (I) iodide (Cul) as catalyst and a suitable base, preferably potassium phosphate (K3PO4), carried out in the heat:

i

i (1b)

The reaction mixture is particularly preferably heated to a high temperature of 160-200 ° C., more preferably about 180 ° C., which drastically shortens the reaction time compared to the literature, namely to 2 to 3 hours instead of 12 or 48 hours, which will be discussed in more detail below. In particular, the heating according to the present invention is carried out by means of microwave radiation, as a result of which the reaction can be completed within 2 hours and the products can be obtained in yields of up to 90%.

A similar reaction is used for the first case, i.e. the implementation of (1a) to (2), as mentioned previously, by Hubijar et al. described for 2-ethylhexylthiol. However, first of all, the 1,4-di (2-ethylhexylthio) benzene obtained is directly one

-89 / 60 para-dihalogenation to 1,4-dibromo-2,5-di (2-ethylhexylthio) benzene and no para-dihalomethylation. Secondly, the use of neocuproin as a ligand for complexing the Cu (l) ions is imperatively disclosed, DMF is used as the solvent and a reaction temperature of 115 ° C. is selected, which results in a reaction time of 48 h. Also Thomas et al., Tetrahedron Lett. 56, 6560-6564 (2015), disclose reaction conditions similar to Hubijar et al. For the reaction of 4-iodoanisole with thiophenol. (Cul, 80-120 ° C, 12 h), and there too the presence of a Cu-complexing ligand is disclosed as being essential, but four different ligands were investigated and with variation of the solvent, the base and the reaction temperature. The inexpensive DABCO, diazabicyclo [2.2.2] octane, gave the best results as a ligand.

Surprisingly, however, upon closer examination of the reaction from (1a) or (1b) to (2), the inventors found that the presence of a ligand is not necessary at all at even higher reaction temperatures of 180-200 ° C.: With and without DABCO practically identical sales achieved, as the later examples demonstrate. The preferred use of a microwave oven for rapid heating of the reaction mixture also made it possible to reduce the reaction time to 2 hours. According to the present invention, the solvent used is preferably dimethoxyethane (DME) (ethylene glycol dimethyl ether), which is also preferred according to Thomas et al., See above, while Hubijar et al. Use DMF, just like the others by Thomas et al. investigated solvents (acetonitrile, water, toluene, THF, DMSO, t-BuOH) can also generally be used according to the present invention. However, the high-boiling water-miscible DME is preferred as the solvent. As a base, Thomas et al. K2CO3, while according to the present invention K3PO4 is used, as also in Hubijar et al., In order to avoid excessive pressure increases due to the release of CO2 at the preferred high temperatures.

The final reaction from 1,4-di (alkylthio) benzene (2) to the corresponding 2,5-di (alkylthio) -a, a'-dihalogen-p-xylene (3) is preferably carried out according to the present invention using the powdered and therefore easy to handle -910 / 60

Paraformaldehyde (PFA) in the form of a solution in a suitable solvent, preferably in an acidic solvent, to cause it to decompose to formaldehyde at room temperature, more preferably in formic acid (HCOOH) or a mixture of trifluoroacetic acid (TFA) and trifluoroacetic anhydride (TFAA) as Reaction medium and introduction or addition of a solution of the corresponding hydrogen halide (HX), more preferably with heating, carried out:

For example, acetic acid can also be used as the medium instead of formic acid, but the reaction products (3) are not precipitated. The mixture of trifluoroacetic acid (TFA) and trifluoroacetic anhydride (TFAA) is preferably used when both R and R 'contain very long alkyl chains, especially when R = R' and both are selected from alkyl radicals with more than 10 carbon atoms.

As mentioned, the hydrogen halide can be introduced as a gas or in the form of a solution, e.g. in the same acid, which is preferably used as the reaction medium, or independently of the choice of the reaction medium in readily available and inexpensive acetic acid. In particularly preferred embodiments, hydrogen bromide is used as the hydrogen halide instead of the more aggressive hydrogen chloride, more preferably as a solution in glacial acetic acid, which is commercially available.

The reaction is preferred to accelerate the course of the reaction and to ensure complete decomposition of paraformaldehyde to formaldehyde

-1011 / 60 with heating, more preferably carried out at a temperature of 70 ° C to 80 ° C.

In preferred embodiments of the process according to the invention, R and R 'are selected from linear or branched Ci-Ci2-alkyl radicals, more preferably C1-C10alkyl radicals. On the one hand, because cyclic residues, for which the person skilled in the art can assume with almost certainty that they can be produced in an analogous manner, may not have the same positive effects on the optoelectronic properties due to steric effects in the later S-PPV molecule, e.g. the HOMO and LUMO energy levels (see Cui and Wong, supra) that polymers have. And on the other hand, with a longer chain length or number of carbon atoms of the radicals, no further increase in the positive effect of the substituents on the optoelectronic properties can be expected, but the production is made more difficult. This has already been shown, for example, with chain lengths of 12 carbon atoms, as has already been indicated and as the later examples demonstrate. R and R 'are particularly preferred from methyl, 2-ethylhexyl,

3.7- dimethyloctyl, n-hexyl and n-dodecyl, in particular from methyl, 2-ethylhexyl,

3.7- Dimethyloctyl and n-hexyl selected, with which good results have already been achieved.

In further aspects, the invention relates to the 2,5-di (alkylthio) -a, a'-dihalogen-p-xylenes of the formula (3), in particular the following, prepared by the process according to the first aspect, in particular by the inventors in the examples established connections:

2.5- di (2-ethylhexylthio) -a, a’-dibromo-p-xylene (3a),

2.5- di (3,7-dimethyloctylthio) -a, a'-dibromo-p-xylene (3b),

2.5- di (hexylthio) -a, a'-dibromo-p-xylene (3c),

2.5- di (dodecylthio) -a, a'-dibromo-p-xylene (3d), 2- (2-ethylhexylthio) -5-methylthio-a, a'-dibromo-p-xylene (3e), 2- ( 3,7-dimethyloctylthio) -5-methylthio-a, a'-dibromo-p-xylene (3f), 2-hexylthio-5-methylthio-a, a'-dibromo-p-xylene (3g) and 2-dodecylthio -5-methylthio-a, a'-dibromo-p-xylene (3h),

-11 12/60 and their use as monomers in polymerization reactions for the preparation of alkylthio-substituted poly (p-phenylene-vinylene) polymers (S-PPVs) (4) with elimination of hydrogen halide in the presence of a base (analogous to the Gilch reaction ):

- HX

(3) (4)

For this purpose, the particular 2,5-di (alkylthio) -a, a'-dihalogen-pxylene is preferably in a dry solvent, more preferably THF, either at room temperature or, more preferably, initially at low temperatures, particularly preferably at about -60 ° C to about -50 ° C, and then allowed to warm to room temperature and in the presence of a base, more preferably potassium tert-butoxide, polymerized, since the inventors could show that this reaction procedure the best sales in the production of S- PPVs (4) delivers.

For the production of PWs and O-PPVs 2 ^nd Ed., Zhigang Rick Li (eds.), CRC Press, for example, in Organic Light-Emitting Materials and Devices, (2015), for various types of Gilch Reaction temperatures between about 60 ° C and about 220 ° C disclosed to achieve the highest possible sales. In diametrical contrast to this, the present inventors have found that for the production of S-PPVs, work should preferably be carried out first at room temperature or more preferably at low temperatures between -60 ° C. and -50 ° C. with subsequent heating to room temperature. In this way, yields of S-PPVs of over 50% or over 90% could be achieved after a reaction time of only 5 h.

-1213 / 60

In particularly preferred embodiments of the use according to the invention of the 2,5-di (alkylthio) -a, adihalogen-p-xylenes (3) prepared by the process according to the first aspect for the preparation of polymers, the alkylthio-substituted S-PPVs (initially obtained) 4) subsequently oxidized to alkyl sulfone-substituted polymers (SO2-PPVS) (5):

(4)

(5)

The inventors are thus the first to have oxidized S-PPVs to SOz-PPVs, i.e. an oxidation of the S-PPVs (4) obtained initially by polymerization of the 2,5-di (alkylthio) -a, a'-dihalogen-p-xylenes (3) to SO2-PPVS (5) was successful. The only SO2-PPV disclosed so far is that mentioned at the beginning, by Hubijar et al. produced poly [2,5-di (2-ethylhexylsulfonyl) phenylene-vinylene] (as SO2-EH-PPV, referred to herein as polymer (4a)), which, however, was obtained from a monomer which had already been oxidized before the polymerization, the subsequent polymerization thereof , as mentioned, was carried out by means of a Stille coupling under palladium catalysis for 24 h.

The oxidation according to the present invention, however, takes place only after the polymerization using a conventional oxidizing agent, such as e.g. H2O2, but preferably using dimethyldioxirane (DMDO), since the inventors' working group had had good experience with this oxidizing agent in the oxidation of other alkylthio-substituted polymers in the past (see Glöcklhofer et al., J. New J. Chem. 38, 2229-2232 (2014); Glöcklhofer et al., J. React. Funct. Polym. 86, 16-26 (2015)). The oxidation reaction is even more preferred by simply stirring a solution of the S-PPV to which DMDO has been added for 10 minutes

-1314 / 60 (4) in a suitable solvent, e.g. Acetone, carried out at room temperature.

In a further aspect, the present invention also relates to the products of the above polymerization reaction, i.e. Alkylthio-substituted poly (p-phenylene-vinylene) polymers (S-PPVs) of the formula (4) prepared in accordance with the invention, in particular one of the following polymers:

Poly [2,5-di (2-ethylhexylthio) phenylene vinylene] (4a),

Poly [2,5-di (3,7-dimethyloctylthio) phenylene vinylene] (4b),

Poly [2,5-di (hexylthio) phenylene vinylene] (4c),

Poly [2,5-di (dodecylthio) phenylene vinylene] (4d),

Poly [2- (2-ethylhexylthio) -5-methylthiophenylene vinylene] (4e), poly [2- (3,7-dimethyloctylthio) -5-methylthiophenylene vinylene] (4f),

Poly [2-hexylthio-5-methylthiophenylene vinylene] (4g) and poly [2-dodecylthio-5-methylthiophenylene vinylene] (4h).

In yet another aspect, the present invention also relates to the products of the above oxidation reaction, i.e. Alkylsulfonyl-substituted poly (p-phenylene-vinylene) polymers (SO2-PPVS) of the formula (5) prepared according to the invention. In particular, the invention relates to one of the following polymers:

Poly [2,5-di (2-ethylhexylsulfonyl) phenylene vinylene] (5a) with a number average molecular weight M _n > 30,000 Da,

Poly [2,5-di (3,7-dimethyloctylsulfonyl) phenylene vinylene] (5b),

Poly [2,5-di (hexylsulfonyl) phenylene vinylene] (5c),

Poly [2,5-di (dodecylsulfonyl) phenylene vinylene] (5d),

Poly [2- (2-ethylhexylsulfonyl) -5-methylsulfonylphenylene vinylene] (5e),

Poly [2- (3,7-dimethyloctylsulfonyl) -5-methylsulfonylphenylene vinylene] (5f), poly [2-hexylsulfonyl-5-methylsulfonylphenylene vinylene] (5g) and

Poly [2-dodecylsulfonyl-5-methylsulfonylphenylene vinylene] (5h).

-1415 / 60

And in a last aspect, the invention relates to several new 2,5-di (alkylthio) -a, a'-dihalogen-p-xylene monomers of the formula (3), which were first produced and characterized by the inventors, namely:

2,5-di (2-ethylhexylthio) -a, a'-dibromo-p-xylene (3a):

2,5-di (3,7-dimethyloctylthio) -a, a'-dibromo-p-xylene (3b):

2,5-di (hexylthio) -a, a'-dibromo-p-xylene (3c):

-1516 / 60

2,5-di (dodecylthio) -a, a'-dibromo-p-xylene (3d):

2- (2-ethylhexylthio) -5-methylthio-a, a'-dibromo-p-xylene (3e):

(3e)

2- (3,7-Dimethyloctylthio) -5-methylthio-a, a'-dibromo-p-xylene (3f):

-1617 / 60

2-Hexylthio-5-methylthio-a, a'-dibromo-p-xylene (3g):

EXAMPLES

The present invention is described in more detail below with the aid of illustrative examples, which, however, are only to be regarded as exemplary and not as a restriction of the scope of protection defined exclusively in the appended claims.

All starting products and reagents were obtained from commercial sources and used directly without further purification, unless otherwise stated. The chemical names and abbreviations have the usual meanings that are well known to those of ordinary skill in the art.

-1718 / 60

Examples 1 to 4, stage 1

Preparation of 1,4-di (alkylthio) benzenes (2a) to (2d) with identical alkyl radicals

R.

S

S.

(1a) (2)

General procedure for the preparation of compounds (2a) to (2d)

1,4-diiodobenzene (990 mg, 3.0 mmol, 1.0 equiv.), Cul (57 mg, 0.3 mmol, 0.1 equiv.) And K3PO4 (2.61 g, 12.3 mmol, 4.1 equiv.) Were weighed into a 20 ml reaction vial and purged with argon. The respective alkylthiol (6.6 mmol, 2.2 equiv.) And 1,2-dimethoxyethane (DME) as solvent (15 ml, 0.2 M) were filled into the vial in a stream of argon, after which it was sealed and stirred was heated to 180 ° C in a microwave oven. When 180 ° C was reached, which usually took about 15-20 minutes, this temperature was held for 2 hours. The reaction mixture was then poured onto 100 ml of water and extracted three times with CH2Cl2 (2x 100 ml, 1x 50 ml). The combined organic phases were dried over Na2SO4 and evaporated in vacuo. The residue was applied dry to a 40 g silica gel column (the respective compound was first dissolved in CH2Cl2, 8 g silica gel was added and the solvent was removed in vacuo) and using petroleum ether (PE) as eluent by means of flash chromatography cleaned.

Scale-up for compounds (2a) and (2b):

Four batches were carried out in a microwave oven as described above, poured together onto 250 ml of water and extracted three times with CH2Cl2 (2x 200 ml, 1x 100 ml). The combined organic phases were dried over Na2SO4 and evaporated in vacuo. The residue was applied dry to a 90 g silica gel column (the respective compound was first dissolved in CH2CI2,

-1819 / 60 g of silica gel were added and the solvent was removed in vacuo) and purified using petroleum ether (PE) as eluent by means of flash chromatography.

Example 1, Step 1: Preparation of 1,4-di (2-ethylenhexylthio) benzene (2a)

( ^1a ) (2a)

The synthesis was carried out according to the general procedure above using 2-ethylhexanethiol (966 mg, 1.15 ml, 6.6 mmol, 2.2 equiv.). Column chromatography gave 838 mg (2.29 mmol, 76%) (2a) as a yellowish liquid. In the scale-up: 3.96 g (10.8 mmol, 90%). ¹ H-NMR (600 MHz, CDCb): δ = 7.23 (s, 4H), 2.87 (d, J = 6.4 Hz, 4H), 1.58-1.52 (m, 2H) , 1.51-1.33 (m, 8H), 1.32-1.22 (m, 8H), 0.91-0.85 (m, 12H) ppm. ¹³ C-NMR (APT) (150 MHz, CDCb): δ = 135.0 (C), 129.7 (CH), 39.0 (CH / CH3), 38.6 (CH2), 32.4 ( CH2), 28.9 (CH2), 25.6 (CH2), 23.1 (CH2), 14.2 (CH / CH3), 10.9 (CH / CH3) ppm.

Example 2, Step 1: Preparation of 1,4-di (3,7-dimethyloctylthio) benzene (2b)

-1920 / 60

The synthesis was carried out according to the general procedure above using 3,7-dimethyloctanethiol (1.15 g, 6.6 mmol, 2.2 equiv.). Column chromatography gave 914 mg (2.16 mmol, 72%) (2b) as a yellowish liquid. In a scale-up: 4.45 g (10.5 mmol, 88%). ¹ H-NMR (600 MHz, CDCb): δ = 7.23 (s, 4H), 2.95-2.83 (m, 4H), 1.67-1.42 (m, 8H), 1, 32-1.19 (m, 6H), 1.16-1.08 (m, 6H), 0.89 (d, J = 6.6 Hz, 6H), 0.86 (d, J = 6, 7 Hz, 12H) ppm. ¹³ C-NMR (APT) (150 MHz, CDCb): δ = 134.5 (C), 129.7 (CH), 39.3 (CH ₂ ), 37.0 (CH ₂ ), 36.3 ( CH ₂ ), 32.4 (CH / CH3), 31.9 (CH ₂ ), 28.1 (CH / CH3), 24.8 (CH ₂ ), 22.8 (CH / CH3), 22.7 (CH / CH3), 19.5 (CH / CH3) ppm.

Example 3, Step 1: Preparation of 1,4-di (hexylthio) benzene (2c)

(1a) (2c)

The synthesis was carried out according to the general procedure above using 1-hexanethiol (780 mg, 0.94 ml, 6.6 mmol, 2.2 equiv.). Column chromatography gave 661 mg (2.13 mmol, 71%) (2c) as a white solid. ¹ H NMR (600 MHz, CDCb): δ = 7.23 (s, 4H), 2.88 (t, J = 7.4 Hz, 4H), 1.62 (quint, J = 7.5 Hz , 4H), 1.41 (quint, J = 7.4 Hz, 4H), 1.33-1.24 (m, 8H), 0.88 (t, J = 6.9 Hz, 6H) ppm. ¹³ C-NMR (APT) (150 MHz, CDCb): δ = 134.5 (C), 129.8 (CH), 34.1 (CH ₂ ), 31.5 (CH ₂ ), 29.2 ( CH2), 28.6 (CH ₂ ), 22.7 (CH ₂ ), 14.2 (CH3) ppm.

Example 4, Step 1: Preparation of 1,4-di (dodecylthio) benzene (2d)

-2021 / 60

The synthesis was carried out according to the general procedure above using 1-dodecanethiol (1.34 g, 1.58 ml, 6.6 mmol, 2.2 equiv.). Column chromatography gave 1.15 g (2.37 mmol, 79%) (2d) as a white solid. ¹ H-NMR (600 MHz, CDCh): δ = 7.23 (s, 4H), 2.88 (t, J = 7.4 Hz, 4H), 1.62 (quint, J = 7.5 Hz , 4H), 1.40 (quint, J = 7.4 Hz, 4H), 1.32-1.21 (m, 32H), 0.88 (t, J = 7.0 Hz, 6H) ppm. ¹³ C-NMR (APT) (150 MHz, CDCh): δ = 134.5 (C), 129.7 (CH), 34.1 (CH2), 32.1 (CH2), 29.80 (CH2) , 29.78 (CH2), 29.73 (CH2), 29.65 (CH2), 29.5 (CH2), 29.31 (CH2), 29.27 (CH2), 29.0 (CH2), 22.8 (CH2), 14.3 (CH3) ppm.

Examples 5 to 8, stage 1

Preparation of 1-iodo-4- (methylthio) benzene (1b) (1a)

1,4-Diiodobenzene (4.95 g, 15.0 mmol, 1.0 equiv.) Was weighed into a 250 ml three-necked round bottom flask equipped with a septum, thermometer and argon balloon. The flask was purged with argon and 150 ml dry dimethyl ether (Et20) was added to dissolve the starting material. The reaction mixture was stirred and cooled to -80 ° C using a cooling bath of acetone and liquid N2. Then 6.6 ml of n-BuLi (2.5 M in hexane, 16.5 mmol, 1.1 equiv.) Were slowly added, and the reaction mixture was stirred for 40 min and allowed to warm up slowly to -65 ° C. The reaction mixture was then cooled to -70 ° C and elemental sulfur (553 mg, 17.25 mmol, 1.15 equiv.) Was added all at once. The reaction mixture was stirred again for 40 minutes after which methyl iodide (4.26 g, 1.87 ml, 30.0 mmol, 2.0 equiv.) Was added. The reaction mixture was then left in the cooling bath and allowed to warm slowly to room temperature overnight. Then 90 ml of a saturated aqueous NH4CI solution were added and the mixture was poured into a

-21 22/60

Transfer funnel. After phase separation, the aqueous phase was extracted three times with Et2O (2x 100 ml, 1x 50 ml). The combined organic phases were washed with water and brine, dried over Na2SO4 and evaporated in vacuo to give 3.31 g (13.2 mmol, 88%) of the crude compound (1b) which then slowly crystallized. ¹ H NMR (400 MHz, CDCb): δ = 7.57 (d, J = 8.5 Hz, 2H), 6.99 (d, J = 8.6 Hz, 2H), 2.45 (s, 3H) ) ppm (without signals of impurities). ¹³ C-NMR (APT) (100 MHz, CDCb): δ = 138.7 (C), 137.7 (CH), 128.3 (CH), 89.3 (C), 15.8 (CH3) ppm (without signals of impurities).

Examples 5 to 8, stage 2

Preparation of 1,4-di (alkylthio) benzenes (2e) to (2h) with different alkyl radicals

R'-SH

(2)

General procedure for the preparation of compounds (2e) to (2h)

Crude 1-iodo-4- (methylthio) benzene (1b) (750 mg, 3.0 mmol, 1.0 equiv), Cul (57 mg, 0.3 mmol, 0.1 equiv) and K3PO4 (2, 61 g, 12.3 mmol, 4.1 equiv.) Were weighed into a 20 ml reaction vial and flushed with argon. The respective alkylthiol (3.6 mmol, 1.2 equiv.) And 1,2-dimethoxyethane (DME) as solvent (15 ml, 0.2 M) were flushed with argon and filled into the vial, after which it was sealed and was heated to 180 ° C. while stirring in a microwave oven. When 180 ° C was reached, which usually took about 15-20 minutes, this temperature was held for 2 hours. The reaction mixture was then poured onto 100 ml of water and extracted three times with CH2Cl2 (2x 100 ml, 1x 50 ml). The combined organic phases were dried over Na2SO4 and evaporated in vacuo. The residue was applied dry to a 40 g silica gel column

-2223 / 60 (the respective compound was first dissolved in CH2Cl2, 6 g of silica gel were added and the solvent was removed in vacuo) and purified using petroleum ether (PE) as eluent by means of flash chromatography.

Example 5, Step 2: Preparation of 1- (2-ethylhexylthio) -4-methylthiobenzene (2e)

(1b) (2e)

The synthesis was carried out according to the general procedure above using 2-ethylhexanethiol (527 mg, 0.62 ml, 3.6 mmol, 1.2 equiv.). Column chromatography gave 643 mg (2.39 mmol, 80%) (2e) as a yellowish liquid. ¹ H NMR (600 MHz, CDCb): δ = 7.26 (d, J = 8.5 Hz, 2H), 7.17 (d, J = 8.5 Hz, 2H), 2.86 (d , J = 6.4 Η, 2H), 2.47 (s, 3H), 1.54 (sept, J = 6.3 Hz, 1H), 1.51-1.33 (m, 4H), 1 , 32-1.21 (m, 4H), 0.91-0.85 (m, 6H) ppm. ¹³ C-NMR (APT) (150 MHz, CDCI3): δ = 135.9 (C), 134.3 (C), 130.0 (CH), 127.5 (CH), 39.0 (CH / CH3), 38.8 (CH2), 32.4 (CH2), 28.9 (CH2), 25.6 (CH2), 23.1 (CH2), 16.3 (CH / CH3), 14.2 (CH / CH3), 10.9 (CH / CH3) ppm.

Example 6, Step 2: Preparation of 1- (3,7-Dimethvloctylthio) -4-methylthiobenzene (2f)

The synthesis was carried out according to the general procedure above using 3,7-dimethyloctanethiol (628 mg, 3.6 mmol, 1.2 equiv.). Column chromatography gave 704 mg (2.37 mmol, 79%) (2f) as a yellowish liquid. ¹ H NMR (600

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MHz, CDCb): δ = 7.26 (d, J = 8.5 Hz, 2H), 7.18 (d, J = 8.5 Hz, 2H), 2.95-2.82 (m, 2H) ), 2.47 (s, 3H), 1.66-1.40 (m, 4H), 1.32-1.18 (m, 3H), 1.16-1.07 (m, 3H), 0.88 (d, J = 6.6 Hz, 3H), 0.86 (d, J = 6.6 Hz, 6H) ppm. ¹³ C-NMR (APT) (150 MHz, CDCb): δ = 136.2 (C), 133.6 (C), 130.1 (CH), 127.4 (CH), 39.3 (CH ₂ ), 37.0 (CH ₂ ), 36.4 (CH ₂ ), 32.3 (CH / CH3), 32.2 (CH ₂ ), 28.1 (CH / CH3), 24.8 (CH ₂ ), 22.8 (CH / CH3), 22.7 (CH / CH3), 19.5 (CH / CH3), 16.3 (CH / CH3) ppm.

Example 7, Step 2: Preparation of 1-Hexylthio-4-methylthiobenzene (2q)

(1b) (2g)

The synthesis was carried out according to the general procedure above using 1-hexanethiol (426 mg, 0.51 ml, 3.6 mmol, 1.2 equiv.). Column chromatography gave 568 mg (2.36 mmol, 79%) (2g) as a white solid. ¹ H NMR (600 MHz, CDCb): δ = 7.26 (d, J = 8.5 Hz, 2H), 7.18 (d, J = 8.5 Hz, 2H), 2.87 (t , J = 7.3 Hz, 2H), 2.47 (s, 3H), 1.61 (quint, J = 7.5 Hz, 2H), 1.40 (quint, J = 7.4 Hz, 2H ), 1.33-1.24 (m, 4H), 0.88 (t, J = 7.0 Hz, 3H) ppm. ¹³ C-NMR (APT) (150 MHz, CDCb): δ = 136.2 (C), 133.6 (C), 130.2 (CH), 127.4 (CH), 34.3 (CH ₂ ), 31.5 (CH ₂ ), 29.3 (CH ₂ ), 28.6 (CH ₂ ), 22.7 (CH ₂ ), 16.3 (CH3), 14.2 (CH3) ppm.

Example 8, Step 2: Preparation of 1-dodecylthio-4-methylthiobenzene (2h)

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The synthesis was carried out according to the general procedure above using 1-dodecanethiol (729 mg, 0.86 ml, 3.6 mmol, 1.2 equiv.). Column chromatography gave 759 mg (2.34 mmol, 78%) (2h) as a white solid. ¹ H NMR (600 MHz, CDCb): δ = 7.26 (d, J = 8.5 Hz, 2H), 7.18 (d, J = 8.5 Hz, 2H), 2.87 (t , J = 7.4 Hz, 2H), 2.47 (s, 3H), 1.61 (quint, J = 7.5 Hz, 2H), 1.39 (quint, J = 7.3 Hz, 2H) ), 1.32-1.21 (m, 16H), 0.88 (t, J = 7.2 Hz, 3H) ppm. ¹³ C-NMR (APT) (150 MHz, CDCb): δ = 136.2 (C), 133.6 (C), 130.2 (CH), 127.4 (CH), 34.3 (CH2) , 32.1 (CH2), 29.79 (CH2), 29.78 (CH2), 29.73 (CH2), 29.65 (CH2), 29.5 (CH2), 29.31 (CH2), 29.30 (CH2), 28.9 (CH2), 22.8 (CH2), 16.3 (CH ₃ ), 14.3 (CH3) ppm.

Examples 1 to 4, stage 2; Examples 5 to 8, level 3

Preparation of 2,5-di (alkylthio) -a, a'-dibromo-p-xylenes (3a) to (3h)

(2) Ο)

General procedure for the preparation of compounds (3a) to (3c) and (3e) to (3h)

The respective 1,4-di (alkylthio) benzene (2) (2.0 mmol, 1.0 equiv.) And paraformaldehyde (PFA) (240 mg, 8.0 mmol, 4.0 equiv.) Were mixed in one with Weighed a 25 ml three-neck round-bottom flask equipped with a thermometer and a reflux condenser with a drying tube (CaCb). Thereafter, 10 ml of formic acid and 2.8 ml of HBr (30% in acetic acid) were added, and the reaction mixture was heated to 70 ° C. After 1 h, 2 h and 3 h reaction time, further PFA (240 mg, 8.0 mmol, 4.0 equiv.) And 2.8 ml HBr (30% in acetic acid) were added. The reaction mixture was stirred at 70 ° C overnight and then allowed to cool to room temperature to ensure complete precipitation of the product. The precipitate was filtered off, washed with a small amount of methanol and dried in vacuo. The

The solid obtained was recrystallized from acetonitrile (agitation facilitates crystallization), filtered off and washed with a small amount of acetonitrile.

Scale-up for compounds (3a) and (3b):

The reactions were carried out as described above, but with 10.0 mmol of 1,4-di (alkylthio) benzene (2) and correspondingly larger amounts of reagents and solvents.

Example 1, stage 2: preparation of 1,4-di (2-ethylenhexylthio) -a, a'-dibromoxylene (3a)

(2a)

The synthesis was carried out according to the general procedure above using 1,4-di (2-ethylhexylthio) benzene (2a) (733 mg, 2.0 mmol, 1.0 equiv.). as a starting product. Recrystallization gave 780 mg (1.41 mmol, 71%) (3a) as an off-white solid. In a scale-up: 3.89 g (7.04 mmol, 70%). ¹ H NMR (600 MHz, CDCh): δ = 7.36 (s, 2H), 4.64 (s, 4H), 2.93 (d, J = 6.2 Hz, 4H), 1.59 (sept, J = 6.3 Hz, 2H), 1.54-1.36 (m, 8H), 1.34-1.24 (m, 8H), 0.92-0.88 (m, 12H) ) ppm. ¹³ C-NMR (APT) (150 MHz, CDCh): δ = 138.3 (C), 135.7 (C), 131.9 (CH), 39.1 (CH / CH3), 38.9 ( CH2), 32.5 (CH2), 31.4 (CH2), 28.9 (CH ₂ ), 25.8 (CH2), 23.1 (CH2), 14.3 (CH / CH3), 11, 0 (CH / CH3) ppm.

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Example 2, stage 2: preparation of 1 ^ -DiOT-dimethyloctvIthioj-a.a'-dibromxylene (3b)

s s

(2b) (3b)

The synthesis was carried out according to the general procedure above using 1,4-di (3,7-dimethyloctylthio) benzene (2b) (846 mg, 2.0 mmol, 1.0 equiv.). as a starting product. Recrystallization gave 793 mg (1.30 mmol, 65%) (3b) as an off-white solid. In a scale-up: 4.75 g (7.81 mmol, 78%). ¹ H-NMR (600 MHz, CDCh): δ = 7.36 (s, 2H), 4.63 (s, 4H), 3.02-2.90 (m, 4H), 1.71-1, 56 (m, 4H), 1.54-1.45 (m, 4H), 1.33-1.20 (m, 6H), 1.18-1.09 (m, 6H), 0.91 ( d, J = 6.5 Hz, 6H), 0.86 (d, J = 6.6 Hz, 12H) ppm. ¹³ C-NMR (APT) (150 MHz, CDCh): δ = 138.3 (C), 135.2 (C), 131.8 (CH), 39.3 (CH2), 37.0 (CH2) , 36.2 (CH2), 32.4 (CH / CH3), 32.2 (CH2), 31.3 (CH2), 28.1 (CH / CH3), 24.8 (CH2), 22.9 (CH / CH3), 22.8 (CH / CH3), 19.5 (CH / CH3) ppm.

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Example 3, Step 2: Preparation of 1,4-di (hexvlthio) -a, a'-dibromxvlol (3c)

(2c) (3c)

The synthesis was carried out according to the general procedure above using 1,4-di (hexylthio) benzene (2c) (621 mg, 2.0 mmol, 1.0 equiv.). as a starting product. Recrystallization gave 618 mg (1.24 mmol, 62%) (3c) as a white solid. ¹ H NMR (600 MHz, CDCb): δ = 7.35 (s, 2H), 4.63 (s, 4H), 2.95 (t, J = 7.4 Hz, 4H), 1.66 (quint, J = 7.5 Hz, 4H), 1.44 (quint, J = 7.4 Hz, 4H), 1.35-1.26 (m, 8H), 0.89 (t, J = 7.0 Hz, 6H) ppm. ¹³ C-NMR (APT) (150 MHz, CDCb): δ = 138.3 (C), 135.2 (C), 131.9 (CH), 34.4 (CH ₂ ), 31.5 (CH ₂ ), 31.3 (CH ₂ ), 29.1 (CH ₂ ), 28.7 (CH ₂ ), 22.7 (CH ₂ ), 14.2 (CH ₃ ) ppm.

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Example 4, Step 2: Preparation of 1,4-di (dodecvlthio) -a, a'-dibromoxylene (3d)

1,4-Di (dodecylthio) benzene (2d) (1.20 g, 2.5 mmol, 1.0 equiv.) And paraformaldehyde (PFA) (450 mg, 15.0 mmol, 6.0 equiv) were added to weighed a 20 ml reaction vial. Trifluoroacetic acid (2.5 ml, 0.1 M), trifluoroacetic anhydride (0.5 ml) and 1.75 ml HBr (30% in acetic acid) were added, the vial was sealed, the contents stirred and opened for 24 hours Heated to 80 ° C. The reaction mixture was then allowed to cool to room temperature to form a precipitate which was filtered off and washed with water and methanol. The solid so obtained was purified by recrystallization from acetonitrile to give 838 mg (1.26 mmol, 50%) (3d) as a white solid. ¹ H-NMR (600 MHz, CDCh): δ = 7.35 (s, 2H), 4.63 (s, 4H), 2.95 (t, J = 7.4 Hz, 4H), 1.66 (quint, J = 7.5 Hz, 4H), 1.43 (quint, J = 7.3 Hz, 4H), 1.33-1.22 (m, 32H), 0.88 (t, J = 7.0 Hz, 6H) ppm. ¹³ C-NMR (APT) (150 MHz, CDCh): δ = 138.3 (C), 135.2 (C), 131.9 (CH), 34.4 (CH2), 32.1 (CH ₂ ), 31.3 (CH2), 29.80 (CH2), 29.79 (CH2), 29.7 (CH2), 29.6 (CH2), 29.5 (CH2), 29.3 (CH2) , 29.1 (CH2), 29.0 (CH2), 22.8 (CH2), 14.3 (CH3) ppm.

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Example 5, Step 3: Preparation of 1- (2-Ethylhexylthio) -4-methylene thio-a, a'-dibromoxylene (3e)

br

br

(2e) (3e)

The synthesis was carried out according to the general procedure above using 1- (2-ethylhexylthio) -4-methylthiobenzene (2e) (537 mg, 2.0 mmol, 1.0 equiv.). as a starting product. Recrystallization gave 498 mg (1.10 mmol, 55%) (3e) as an off-white solid. ¹ H NMR (600 MHz, CDCb): δ = 7.36 (s, 1H), 7.27 (s, 1H), 4.66 (s, 2H), 4.59 (s, 2H), 2 , 92 (d, J = 6.2 Hz, 2H), 2.52 (s, 3H), 1.61-1.36 (m, 5H), 1.34-1.24 (m, 4H), 0.90 (t, J = 7.4 Hz, 6H) ppm. ¹³ C-NMR (APT) (150 MHz, CDCb): δ = 138.7 (C), 136.75 (C), 136.66 (C), 135.0 (C), 132.1 (CH) , 129.2 (CH), 39.12 (CH / CH3), 39.11 (CH ₂ ), 32.5 (CH ₂ ), 31.5 (CH ₂ ), 31.0 (CH ₂ ), 28 , 9 (CH ₂ ), 25.7 (CH ₂ ), 23.1 (CH ₂ ), 16.5 (CH / CH3), 14.2 (CH / CH3), 10.9 (CH / CH3) ppm ,

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Example 6, Step 3: Preparation of 1- (3,7-Dimethvloctylthio) -4-methylthio-a, a'-dibromoxylene (3f)

(2f) (3f)

The synthesis was carried out according to the general procedure above using 1- (3,7-dimethyloctylthio) -4-methylthiobenzene (2f) (593 mg, 2.0 mmol, 1.0 equiv.). as a starting product. Recrystallization gave 578 mg (1.20 mmol, 60%) (3f) as an off-white solid. ¹ H-NMR (600 MHz, CDCb): δ = 7.35 (s, 1H), 7.27 (s, 1H), 4.66 (s, 2H), 4.59 (s, 2H), 3 , 01-2.89 (m, 2H), 2.53 (s, 3H), 1.70-1.44 (m, 4H), 1.331.19 (m, 3H), 1.17-1.09 (m, 3H), 0.91 (d, J = 6.6 Hz, 3H), 0.86 (d, J = 6.6 Hz, 6H) ppm. ¹³ C-NMR (APT) (150 MHz, CDCI3): δ = 138.8 (C), 136.9 (C), 136.7 (C), 134.3 (C), 132.1 (CH) , 129.2 (CH), 39.3 (CH2), 37.0 (CH2), 36.2 (CH2), 32.43 (CH2), 32.39 (CH / CH3), 31.4 (CH ₂ ), 31.0 (CH2), 28.1 (CH / CH3), 24.8 (CH2), 22.9 (CH / CH3), 22.8 (CH / CH3), 19.5 (CH / CH3), 16.5 (CH / CH3) ppm.

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Example 7, Step 3: Preparation of 1-Hexvlthio-4-methvlthio-a, a'-dibromoxylene (3g)

(2g) (3g)

The synthesis was carried out according to the general procedure above using 1-hexylthio-4-methylthiobenzene (2g) (481 mg, 2.0 mmol, 1.0 equiv.). as a starting product. Recrystallization gave 538 mg (1.26 mmol, 63%) (3g) as an off-white solid. ¹ H-NMR (600 MHz, CDCh): δ = 7.35 (s, 1H), 7.27 (s, 1H), 4.66 (s, 2H), 4.59 (s, 2H), 2 , 94 (t, J = 7.5 Hz, 2H), 2.53 (s, 3H), 1.65 (quint, J = 7.5 Hz, 2H), 1.44 (quint, J = 7, 4 Hz, 2H), 1.34-1.26 (m, 4H), 0.89 (t, J = 7.0, 3H) ppm. ¹³ C-NMR (APT) (150 MHz, CDCh): δ = 138.8 (C), 136.9 (C), 136.7 (C), 134.3 (C), 132.2 (CH) , 129.2 (CH), 34.6 (CH ₂ ), 31.5 (CH ₂ ), 31.4 (CH ₂ ), 31.0 (CH ₂ ), 29.1 (CH ₂ ), 28, 6 (CH ₂ ), 22.7 (CH ₂ ), 16.5 (CH ₃ ), 14.2 (CH ₃ ) ppm.

Example 8, stage 3: preparation of 1-dodecvlthio-4-methvlthio-a.a'-dibromxvlol (3h)

-3233 / 60

The synthesis was carried out according to the general procedure above using 1-hexylthio-4-methylthiobenzene (2g) (481 mg, 2.0 mmol, 1.0 equiv.). as a starting material, but in this case heating was carried out to 80 ° C instead of 70 ° C. Recrystallization gave 721 mg (1.41 mmol, 71%) (3h) as an off-white solid. ¹ H-NMR (600 MHz, CDCb): δ = 7.35 (s, 1H), 7.27 (s, 1H), 4.66 (s, 2H), 4.59 (s, 2H), 2 , 94 (t, J = 7.4 Hz, 2H), 2.53 (s, 3H), 1.65 (quint, J = 7.5 Hz, 2H), 1.43 (quint, J = 7, 5 Hz, 2H), 1.33-1.22 (m, 16H), 0.88 (t, J = 7.0 Hz, 3H) ppm. ¹³ C-NMR (APT) (150 MHz, CDCb): δ = 138.8 (C), 136.9 (C), 136.7 (C), 134.3 (C), 132.2 (CH) , 129.2 (CH), 34.6 (CH ₂ ), 32.1 (CH ₂ ), 31.4 (CH ₂ ), 31.0 (CH ₂ ), 29.80 (CH ₂ ), 29, 78 (CH ₂ ), 29.7 (CH ₂ ), 29.6 (CH ₂ ), 29.5 (CH ₂ ), 29.3 (CH ₂ ), 29.1 (CH ₂ ), 29.0 ( CH ₂ ), 22.8 (CH ₂ ), 16.5 (CH ₃ ), 14.3 (CH3) ppm.

Examples 1 to 4, stage 3: Examples 5 to 8, stage 4

Preparation of the poly [2,5-di (alkylthio) phenylene-vinylene] polymers (4a) to (4h)

br

br

-HX (3)

General procedure for the production of S-PPV polymers

A) At room temperature:

The respective 2,5-di (alkylthio) -a, a'-dibromo-p-xylene (3) (0.30 mmol, 1 equiv.) Was weighed into a 100 ml three-necked round-bottomed flask equipped with a septum and an argon balloon , The flask was purged with argon and 30 ml of degassed, dry THF was added. The resulting solution was bubbled with argon for 15 minutes. In the meantime, 1.5 ml of potassium tert-butoxide (KOtBu) (1.0 M in THF, 1.50 mmol, 5.0 equiv.) Was diluted with 3 ml of dry THF (to prevent precipitation

-3334 / 60 prevent), bubbled with argon for 2 min and then added all at once into the flask. The reaction mixture was stirred at room temperature for 5 hours and then slowly poured into 150 ml of methanol to precipitate the product. The solid obtained was filtered off and dried in vacuo to determine the crude yield. For cleaning, the solid was first treated with methanol (1 h) and then with hexane (1 h) in a Soxhlet extractor to remove impurities. Finally, the soluble fraction was extracted with CHCb and evaporated, leaving the respective pure polymer as a red solid.

B) At -60 ° C:

The above procedure was repeated, except that the monomer (3) and THF solution was cooled to -60 ° C using a CHCh-liquid N2 cooling bath before the KOfBu solution was added to start the polymerization and the reaction mixture for 3 h at -60 ° C to -55 ° C, then warmed to room temperature within 1 h and then stirred for a further 1 h at room temperature. The processing and cleaning were analogous to the above.

Scale-up for compounds (4a) and (4b):

The reactions were carried out according to procedure B) above, but in a 250 ml three-necked round bottom flask and using 1.0 mmol of the monomers (3) as starting material and correspondingly larger amounts of KOfBu solution and solvents. The monomer solution was bubbled with argon for 30 minutes, the KofBu solution for 4 minutes.

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Example 1, Step 3: Preparation of poly [2,5-di (2-ethylhexylthio) phenylene-vinylene1 (4a)

(3a) (4a)

The synthesis was carried out according to the general procedure above using 2,5-di (2-ethylhexylthio) -a, a’-dibromo-p-xylene (3a) (166 mg, 0.30 mmol, 1 equiv.). as a starting product. The yields were as follows:

A) at room temperature: crude yield 71 mg (61%) and pure yield 65 mg (55%)

B) at -60 ° C: crude yield 85 mg (73%) and pure yield 79 mg (68%), in scale-up: crude yield 352 mg (90%), pure yield 346 mg (89%), each on red solid (4a) ,

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Example 2, Step 3: Preparation of poly [2,5-di (3,7-dimethyloctvlthio) phenylene-vinylene1 (4b)

The synthesis was carried out according to the general procedure above using 2,5-di (3,7-dimethyloctylthio) -a, a'-dibromo-p-xylene (3b) (183 mg, 0.30 mmol, 1 equiv.) , as a starting product. The yields were as follows:

A) at room temperature: raw yield 70 mg (52%) and pure yield 63 mg (47%)

B) at -60 ° C: raw yield 86 mg (64%) and pure yield 75 mg (56%), in scale-up: raw yield 342 mg (77%), pure yield 299 mg (67%), each on red solid (4b) ,

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Example 3, Step 3: Preparation of Poly [2,5-di (hexvlthio) phenvlen-vinvlen1 (4c)

The synthesis was carried out according to the general procedure B) above at -60 ° C. using 2,5-di (hexylthio) -a, a'-dibromo-p-xylene (3c) as the starting product with yields of 62% (crude) or 19% (pure).

Example 4, Step 3: Preparation of Polvi2,5-di (dodecylthio) phenylene-vinvlenl (4d)

/ 60

The synthesis was carried out in accordance with the general procedure B) above at -60 ° C. using 2,5-di (dodecylthio) -a, a'-dibromo-p-xylene (3d) as starting product with yields of 60% (crude) or 17% (pure).

Example 5, Step 4: Preparation of Poly [2- (2-ethylhexylthio) -5-methylthiophenylenevinylenl (4e)

Br (4e)

The synthesis was carried out in accordance with general procedure B) above at -60 ° C. using 2- (2-ethylhexylthio) -5-methylthio-a, a'-dibromo-p-xylene (3e) as starting product with yields of 67% (raw) or 4% (pure).

Example 6, Step 4: Preparation of poly [2- (3,7-dimethyloctylthio) -5-methylthiophenylene vinylenl (4f)

S

br

br

S

- HX

S

S n

(3f) (4f)

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The synthesis was carried out according to the general procedure B) above at -60 ° C. using 2- (3,7-dimethyloctylthio) -5-methylthio-a, a ^, -dibromo-p-xylene (3f) as a starting product with yields of 49% (raw) or 6% (pure).

Example 7, Step 4: Preparation of Poly [2-hexvlthio-5-methvlthiophenvlen-vinvlenl (4g)

(3g)

- HX

(4g)

The synthesis was carried out according to the general procedure B) above at -60 ° C using 2-hexylthio-5-methylthio-a, a'-dibromo-p-xylene (3g) as a starting product with yields of 41% (crude) or 8% (pure).

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Example 8, Step 4: Preparation of Polv [2-dodecvlthio-5-methylthiophenvlen-vinvlen1

14h)

The synthesis was carried out according to the general procedure B) above at -60 ° C using 2-dodecylthio-5-methylthio-a, a'-dibromo-p-xylene (3h) as a starting product with yields of 37% (crude) or . 5% (pure).

The optimization of the polymerization conditions for the production of the S-PPVs - in particular with regard to the selection of the solvent, since in some cases the product has precipitated during the polymerization - is the subject of current research.

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Examples 1 to 4, Level 4; Examples 5 to 8, level 5

Preparation of the poly [2,5-di (alkylsulfonyl) phenylene-vinylene] polymers (5a) to (5h)

R \ s

s \ n

R '(4)

(5)

General procedure for the preparation of the SCh-PPV polymers

The respective poly [2,5-di (alkylthio) phenylene vinylene] polymer (4) obtained (according to procedure B) was dissolved in 30 ml of CHCh and 8.8 ml of dimethyldioxirane (DMDO) (0.077 M in acetone, 0 , 68 mmol, 4.5 equiv.) Were added and the reaction mixture was stirred for 10 min at room temperature, after which the solvent and excess DMDO were distilled off, the respective oxidized polymer remaining as a yellow solid.

Example 1, Step 4: Preparation of Polyf2,5-di (2-ethlhexyl sulfonyl) phenylene-vinylene1 (5a)

DMDO, RT n

S

n

The synthesis was carried out according to the general procedure above, using poly [2,5-di (2-ethylhexylthio) phenylene vinylene] (4a) as the starting product,

-41 42/60 whereby the polymer (5a) was obtained as a light yellow solid in quantitative yield. Polymer (5a) was found to be insoluble in all common solvents.

Example 2, Step 4: Preparation of Polv [2,5-di (3,7-dimethvloctvlsulfonyl) phenylenevinylenl (5b)

The synthesis was carried out according to the general procedure above using poly [2,5-di (3,7-dimethyloctylthio) phenylene vinylene] (4b) as the starting product, the polymer (5b) being obtained as an orange-yellow solid in quantitative yield has been. Polymer (5b) was found to be insoluble in all common solvents.

-4243 / 60

Example 3, Step 4: Preparation of Poly [2,5-di (hexvlsulfonvl) phenvlen-vinvlen1 (5c)

The synthesis was carried out according to the above general procedure using poly [2,5-di (hexylthio) phenylene-vinylene] (4c) as the starting product, the polymer (5c) being obtained as a yellow solid in quantitative yield. Polymer (5c) was found to be insoluble in all common solvents.

-4344 / 60

Example 4, Step 4: Preparation of poly [2,5-di (dodecvlsulfonvl) phenylene-vinylene1 (5d)

The synthesis was carried out according to the general procedure above, using poly [2,5-di (dodecylthio) phenylene vinylene] (4d) as the starting product, the polymer (5d) being obtained as a yellow solid in quantitative yield. Polymer (5d) was found to be insoluble in all common solvents.

Example 5, Step 5: Preparation of Polyf2- (2-ethvlhexylsulfonvl) -5-methvlsulfonylphenylene-vinylenl (5e)

-4445 / 60

The synthesis was carried out according to the general procedure above, using poly [2- (2-ethylhexylthio) -5-methylthiophenylene vinylene] (4e) as the starting product, the polymer (5e) being obtained as a yellow solid in quantitative yield. Polymer (5e) was found to be insoluble in all common solvents.

Example 6, Step 5: Preparation of poly [2- (3,7-dimethvloctvlsulfonvl) -5-methvl sulfonylphenylene-vinylenl (5f)

The synthesis was carried out according to the above general procedure using poly [2- (3,7-dimethyloctylthio) -5-methylthiophenylene vinylene] (4f) as the starting product, the polymer (5f) being obtained as a yellow solid in quantitative yield. Polymer (5f) was found to be insoluble in all common solvents.

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Example 7, Step 5: Preparation of Poly [2-hexvlsulfonvl-5-methvlsulfonylphenvlenvinylenl (5g)

(4g) (5g)

The synthesis was carried out according to the general procedure above using poly [2-hexylthio-5-methylthiophenylene vinylene] (4g) as the starting product, the polymer (5g) being obtained as a yellow solid in quantitative yield. Polymer (5g) was found to be insoluble in all common solvents.

Example 8, Step 5: Preparation of Poly [2-dodecvlsulfonyl-5-methvlsulfonvlphenvlen vinylenl (5h)

-4647 / 60

The synthesis was carried out according to the general procedure above using poly [2-dodecylthio-5-methylthiophenylene vinylene] (4h) as the starting product, the polymer (5h) being obtained as a yellow solid in quantitative yield. Polymer (5h) was found to be insoluble in all common solvents.

Molar masses of SCh-PPV polymers:

Due to the insolubility of the oxidized polymers in all common solvents, it was impossible to determine the molar mass directly. Based on the first results of GPC molecular weight determinations of the precursors, ie the S-PPVs (4a) to (4h), and assuming that the degree of polymerization does not change to any appreciable extent during the oxidation reaction to the sulfonyl-substituted polymers, can with it is almost certainly certain that at least the two oxidized polymers of Examples 1 and 2, ie poly [2,5-di (2ethylhexylsulfonyl) phenylene-vinylene] (5a) and poly [2,5-di (3,7- dimethyloctylsulfonyl) phenylene-vinylene] (5b) have a number average molecular weight M _n of at least 30,000 Da and a weight average molecular weight Mw of at least 90,000 Da.

This corresponds in each case to around three times the values that have been given for the only poly [2,5-di (alkylsulfonyl) phenylene-vinylene] polymer that has been adequately characterized in the literature to date, namely the polymer referred to as SO2EH-PPV according to Hubijar et al. , for which an M _n of 10,600 Da and an Mw of 27,800 Da are given.

Although this literature-known SO2-PPV formally corresponds to the poly [2,5-di (2-ethylhexylsulfonyl) phenylene-vinylene] (5a) according to the present invention, it was, however, in completely different ways, namely, as mentioned at the beginning, by polymerizing an already oxidized monomer receive. The latter was also not a di (alkylsulfonyl) dibromoxylene, which is converted to SO2-PPV by homopolymerization, but a di (alkylsulfonyl) dibromobenzene, which was treated with trans-1,2-bis (tri-n-butylstannyl) ethylene under palladium-catalyzed silence Coupling was copolymerized, what

-4748 / 60 represents a logical explanation for the person skilled in the art that Hubijar et al. could obtain a polymer with only a relatively low molecular weight.

As a result, the Hubijar et al. but also properties that differ significantly from those of poly [2,5-di (2-ethylhexylsulfonyl) phenylene vinylene] (5a) according to the present invention - above all good solubility in common organic solvents (readily soluble in common organic solvents, such as THF, chloroform and toluene). This good solubility is described by Hubijar et al. attributed to the two alkylsulfonyl side chains, which seems to be incorrect in view of the insolubility of the two SO2-PPVS (5a) and (5b) according to the invention in all common solvents.

Because of these enormous differences, there is no doubt that the Hubijar et al. was a substance other than the high molecular weight poly [2,5di (2-ethylhexylsulfonyl) phenylene vinylene] (5a) of the present invention, which is why the SO2-PPV (5a) with a number average molecular weight Mn> 30,000 Da is also within the scope of the present invention Invention should lie.

Claims (4)

1. Process for the preparation of 2,5-di (alkylthio) -a, a'-dihalogen-p-xylenes of the following formula (3), ^R \ ^ R '(3) wherein R and R' are each independently selected from saturated, linear, branched or cyclic Ci-Czo-alkyl radicals and X is selected from CI and Br, comprising the conversion of 1,4-diiodobenzene (1a) to 1,4-di (alkylthio) benzenes (2) and their para-halomethylation by reaction with formaldehyde (CH2O) in the presence of the corresponding hydrogen halide (HX) to the corresponding 2.5- di (alkylthio) -a, a'-dihalogen-p-xylenes (3), where either: i) if R = R ', 1,4-diiodobenzene (1a) directly with 2 mol thiol of the formula R-SH to the corresponding 1,4-di (alkylthio) benzene (2) and then to the corresponding 2.5- di (alkylthio) -a, a'-dihalogen-p-xylene (3) is reacted: or ii) if R φ R ', 1,4-diiodobenzene (1a) first with 1 mol alkyl iodide of the formula Rl to the corresponding 4- (alkylthio) iodobenzene (1b), then with 1 mol thiol of the formula R'-SH to mixed 1,4-di (alkylthio) benzene (2) and finally in analog -5050 / 60 How to react with formaldehyde to give mixed 2,5-di (alkylthio) -a, a'-dihalogen-pxylene (3): (1a) (3) 2. The method according to claim 1, characterized in that the reaction of 1,4-diiodobenzene (1a) with 1 mol of alkyl iodide of the formula R1 to the corresponding 4- (alkylthio) iodobenzene (1 b) in a known manner in the cold under Use of n-butyllithium (n-BuLi) and elemental sulfur (Se), preferably in diethyl ether, is carried out: 3. The method according to claim 1 or 2, characterized in that the reaction of 1,4-diiodobenzene (1a) or 4- (alkylthio) iodobenzene (1b) to the respective 1,4-di (alkylthio) benzene (2) with 2 mol of thiol of the formula R-SH or 1 mol of thiol of the formula R'-SH using copper (l) iodide (Cul) as a catalyst and potassium phosphate (K3PO4) as a base is carried out in the heat: -51 51/60 4. The method according to claim 3, characterized in that the reaction mixture is heated to a temperature of 160-200 ° C, preferably about 180 ° C. 5. The method according to claim 3 or 4, characterized in that the heating takes place by means of microwave radiation. 6. The method according to any one of claims 1 to 5, characterized in that the reaction of 1,4-di (alkylthio) benzene (2) to the corresponding 2,5-di (alkylthio) α, α'-dihalogen-p-xylene (3) using paraformaldehyde (PFA) in formic acid (HCOOH) or a mixture of trifluoroacetic acid (TFA) and trifluoroacetic anhydride (TFAA) as the reaction medium and adding a solution of the corresponding hydrogen halide (HX), preferably with heating: PFA in HCOOH or TFA / TFAA, HX (2) (3) -5252 / 60 7. The method according to claim 6, characterized in that the 1,4-di (alkylthio) benzenes (2) are reacted with paraformaldehyde (PFA) in the presence of a solution of hydrogen bromide (HBr) in acetic acid (AcOH) in order to heat to obtain the corresponding 2,5-di (alkylthio) -a, a'-dibromo-p-xylenes of the formula (3): PFA in HCOOH or TFA / TFAA, HBr in AcOH ΔΗ (2) (3) 8. The method according to claim 7, characterized in that the reaction is carried out at a temperature of 70 ° C to 80 ° C. 9. The method according to any one of claims 6 to 8, characterized in that when R and R 'are selected from alkyl radicals having more than 10 carbon atoms, a mixture of trifluoroacetic acid (TFA) and trifluoroacetic anhydride (TFAA) is used as the reaction medium. 10. The method according to any one of claims 1 to 9, characterized in that R and R 'are selected from linear or branched Ci-Ci2-alkyl radicals. 11. The method according to claim 10, characterized in that R and R 'are selected from the following radicals: methyl, 2-ethylhexyl, 3,7-dimethyloctyl, n-hexyl and n-dodecyl. 12. 2,5-di (alkylthio) -a, a'-dihalogen-p-xylene of the formula (3), prepared by a process according to any one of claims 1 to 11. 13. 2,5-di (alkylthio) -a, a'-dihalogen-p-xylene according to claim 12, characterized in that it is selected from the following compounds: -5353 / 60 2.5- di (2-ethylhexylthio) -a, a'-dibromo-p-xylene (3a), 2.5- di (3,7-dimethyloctylthio) -a, a'-dibromo-p-xylene (3b), 2.5- di (hexylthio) -a, a'-dibromo-p-xylene (3c), 2.5- di (dodecylthio) -a, a'-dibromo-p-xylene (3d), 2- (2-ethylhexylthio) -5-methylthio-a, a'-dibromo-p-xylene (3e), 2- (3,7-dimethyloctylthio) -5-methylthio-a, a'-dibromo-p-xylene (3f), 2-hexylthio-5-methylthio-a, a'-dibromo-p-xylene (3g) and 2-dodecylthio-5-methylthio-a, a'-dibromo-p-xylene (3h). 14. Use of 2,5-di (alkylthio) -a, a'-dihalogen-p-xylenes of the formula (3), prepared by a process according to any one of claims 1 to 11 or as defined in claim 12 or 13, as Monomers in polymerization reactions for the preparation of alkylthio-substituted poly (p-phenylene-vinylene) polymers (S-PPVs) (4) with elimination of hydrogen halide in the presence of a base: -HX (4) 15. Use according to claim 14, characterized in that the respective 2,5-di (alkylthio) -a, a'-dihalogen-p-xylene (3) in a dry solvent, preferably THF, at low temperatures in the presence of potassium tert-butoxide is polymerized as a base. 16. Use according to claim 15, characterized in that the polymerization is carried out at room temperature or initially at a temperature of about -60 ° C to -50 ° C. -5454 / 60 17. Use according to one of claims 14 to 16, characterized in that the alkylthio-substituted poly (p-phenylene-vinylene) polymers (SPPVs) (4) obtained subsequently to alkylsulfone-substituted polymers (SO ₂ -PPVs) (5) are oxidized: (4) (5) 18. Use according to claim 17, characterized in that the oxidation is carried out with dimethyldioxirane. 19. Alkylthio-substituted poly (p-phenylene-vinylene) polymer (S-PPV) of the formula (4), prepared according to one of claims 14 to 16. 20. alkylthio-substituted poly (p-phenylene-vinylene) polymer (S-PPV) according to claim 19, characterized in that it is selected from the following polymers: Poly [2,5-di (2-ethylhexylthio) phenylene vinylene] (4a), poly [2,5-di (3,7-dimethyloctylthio) phenylene vinylene] (4b), Poly [2,5-di (hexylthio) phenylene vinylene] (4c), Poly [2,5-di (dodecylthio) phenylene vinylene] (4d), poly [2- (2-ethylhexylthio) -5-methylthiophenylene vinylene] (4e), Poly [2- (3,7-dimethyloctylthio) -5-methylthiophenylene vinylene] (4f), poly [2-hexylthio-5-methylthiophenylene vinylene] (4g) and Poly [2-dodecylthio-5-methylthiophenylene vinylene] (4h). -5555 / 60 21. Alkylsulfonyl-substituted poly (p-phenylene-vinylene) polymer (SO2-PPV) of the formula (5), prepared according to claim 17 or 18. 22. Alkylsulfonyl-substituted poly (p-phenylene-vinylene) polymer (S-PPV) according to claim 21, characterized in that it is selected from the following polymers: Poly [2,5-di (2-ethylhexylsulfonyl) phenylene vinylene] (5a) with a number average molecular weight Mn> 30,000 Da, Poly [2,5-di (3,7-dimethyloctylsulfonyl) phenylene vinylene] (4b), poly [2,5-di (hexylsulfonyl) phenylene vinylene] (4c), Poly [2,5-di (dodecylsulfonyl) phenylene vinylene] (4d), poly [2- (2-ethylhexylsulfonyl) -5-methylsulfonylphenylene vinylene] (4e), poly [2- (3,7-dimethyloctylsulfonyl) - 5-methylsulfonylphenylene vinylene] (4f), poly [2-hexylsulfonyl-5-methylsulfonylphenylene vinylene] (4g) and poly [2-dodecylsulfonyl-5-methylsulfonylphenylene vinylene] (4h). 23. 2,5-Di (2-ethylhexylthio) -a, a'-dibromo-p-xylene (3a): 24th (3a) 2,5-di (3,7-dimethyloctylthio) -a, a'-dibromo-p-xylene (3b): (3b) -5656 / 60 27. 2- (2-ethylhexylthio) -5-methylthio-a, a'-dibromo-p-xylene (3e): (3e) -5757 / 60 28. 2- (3,7-Dimethyloctylthio) -5-methylthio-a, a'-dibromo-p-xylene (3f): 29. 2-Hexylthio-5-methylthio-a, a'-dibromo-p-xylene (3g): 30. 2-dodecylthio-5-methylthio-a, a'-dibromo-p-xylene (3h): (3h)