DE102004029774A1 - New 3,4-alkylenedioxy-2,5-dialkoxy-tetrahydrofuran and/or 3,4-arylendioxy-2,5-dialkoxy-tetrahydrofuran compounds useful for preparing e.g. 3,4-alkylenedioxythiophene and/or 3,4-arylenedioxythiophene and 3,4-alkylenedioxyselenophene - Google Patents

Abstract

3,4-alkylenedioxy-2,5-dialkoxy-tetrahydrofuran and/or 3,4-arylendioxy-2,5-dialkoxy-tetrahydrofuran compounds (III) are new. 3,4-alkylenedioxy-2,5-dialkoxy-tetrahydrofuran and/or 3,4-arylendioxy-2,5-dialkoxy-tetrahydrofuran compounds of formula (III) are new. X : 2-30C alkylene or 6-30C arylene (both optionally substituted); and R, Ra : 1-12C alkyl. Independent claims are also included for: (1) the preparation of (III); and (2) the use of (III) for preparing 3,4-alkylenedioxythiophene and/or 3,4-arylenedioxythiophene compounds. [Image].

Description

The The present invention relates to novel 3,4-alkylenedioxy-2,5-dialkoxytetrahydrofurans or 3,4-arylenedioxy-2,5-dialkoxy-tetrahydrofurans and a two-stage Process for their preparation starting from 2,5-dialkoxydihydrofurans. The invention further relates to the use thereof for the production of S, Se, and N containing Heterocycles, in particular of 3,4-alkylenedioxythiophenes.

3,4-alkylenedioxythiophenes including 3,4-ethylenedioxythiophene, are known. They become, for example used in the electronics industry, especially after polymerization to electrically conductive Polythiophenes. The polymers are used, for example, as electrodes, Sensors, for the production of capacitors or of electroluminescent Displays and other electro-optical components, photovoltaic devices, used as electrochromic layers or in ion exchange membranes.

to Synthesis of 3,4-alkylenedioxythiophenes is a 4-step process known. In the 1st stage, oxalic acid esters and 2,2'-thiodiacetic acid esters to 3,4-dihydroxythiophene-2,5-dicarboxylic acid esters condensed. In the 2nd stage, the hydroxy groups with a suitable Alkylating agent, such as, for example, 1,2-dichloroethane to form 3,4-ethylenedioxythiophene-2,5-dicarboxylic reacted. In the 3rd stage, the ester groups become free carboxylic acid groups saponified, and the carboxylic acid is decarboxylated to EDOT in the 4th stage. This method or individual stages thereof are described, for example, in EP-A 1 167 368, EP-A 1 142 888, DE-A 100 29 078 or EP-A 1 298 133. A 4-stage Synthesis, however, is very complicated and accordingly expensive.

It is also known, 3,4-dialkoxythiophene starting from 3,4-dibromothiophene to synthesize (Z. Z. Mortensen, B. Hedegaard, S.-O. Lawesson, Tetrahedron 1971, 27, 3839-3851). The difficult synthetic approach to 3,4-dibromothiophene makes a technical implementation but little attractive because of direct bromination of thiophene derivatives arise primarily 2-bromo and 2,5-Dibromthiophene.

task The invention therefore was a more economical synthesis of To provide 3,4-alkylenedioxythiophenes.

Was solved the task by providing novel 3,4-alkylenedioxy-2,5-dialkoxy-tetrahydrofurans or 3,4-arylenedioxy-2,5-dialkoxy-tetrahydrofurans, and a two-step process for their preparation starting from dialkoxydihydrofurans. The novel compounds can for the preparation of 3,4-alkylenedioxythiophenes or 3,4-arylenedioxythiophenes are used. They let themselves in a simple way by means of a one-step reaction in convert the corresponding thiophene derivatives.

More specifically, the following is to be accomplished for the invention:
The novel 3,4-alkylenedioxy-2,5-dialkoxy-tetrahydrofurans or 3,4-arylenedioxy-2,5-dialkoxy-tetrahydrofurans have the general formula (III).

at the rest X is a linear or branched, optional substituted alkylene groups having 2 to 30 carbon atoms or one substituted or unsubstituted arylene radical having 6 to 30 carbon atoms. at the arylene radicals are vicinal radicals, i. the link with the O atoms are via adjacent C-atoms.

Prefers it is an alkylene radical having 2 to 12 carbon atoms, especially preferably with 2 to 6 carbon atoms and very particularly preferably around one Alkylene radical with 2 or 3 C atoms.

The radical X may be, for example, 1, ω-alkylene radicals of the general formula - (CH ₂ ) _n han spindles. Here, n preferably represents a natural number of 2 to 12, particularly preferably 2 to 6 and very particularly preferably 2 or 3. It may be, for example, an ethylene, 1,3-propylene, 1,4-butylene or 1 , 6-Hexylenrest act.

The alkylene radicals may optionally be substituted. They may have one or more substituents R ^{1 of the} same or different type. Suitable substituents are, in particular, linear or branched alkyl, aralkyl, aryl or alkylaryl radicals having 1 to 12 C atoms.

Examples linear or branched alkyl radicals include methyl, ethyl, 1-propyl, 2-propyl, 1-butyl, 2-butyl, t-butyl, 1-pentyl, 1-hexyl, 2-ethyl-1-hexyl, 1-octyl, 1-decyl or 1-dodecyl groups. They are preferably linear alkyl groups.

at Aralkyl groups are in a known manner with Aryl groups substituted alkyl groups. Examples include a Benzyl or phenylethyl group. An aryl radical may be for example, be a phenyl group. For alkylaryl radicals it is in a known manner to alkyl-substituted Aryl radicals. For example it may be a 4-alkylphenyl radical, in particular a 4-methylphenyl radical act.

The radicals R ¹ may also have further substituents, in particular those selected from the group of -F, -Cl, -Br, -OH or = O and / or may be non-adjacent non-terminal C atoms in the radicals by O. Atoms are substituted.

The substituents R ^{1 are} preferably linear or branched alkyl radicals having 1 to 6 C atoms.

Further preferably, the alkylene groups have not more than two identical or different substituents R ¹ . The alkylene groups particularly preferably have only one substituent R ¹ . Two different substituents R ¹ , in particular substituents arranged on adjacent C atoms of the alkylene group, may also be connected to one another in a ring. Particularly preferred are 5-rings or 6-rings. For example, it may be a 1,2-cyclopentylene or a 1,2-cyclohexylene.

The alkylene radicals are preferably an ethylene radical -CH ₂ -CH ₂ - or a singly substituted ethylene radical -CHR ¹ -CH ₂ -. Examples of substituted ethylene radicals include -CH (CH ₃ ) -CH ₂ -, -CH (C ₂ H ₅ ) -CH ₂ -, -CH (nC ₃ H ₇ ) -CH ₂ -, -CH (iC ₃ H ₇ ) - CH ₂ -, -CH (C ₄ H ₉ ) -CH ₂ -Reste.

The arylene radicals are preferably arylene radicals having 6 to 14 C atoms. The arylene radicals may each also be substituted with one or more radicals R ^1, where R ¹ has the above described meaning.

Examples of suitable arylene radicals include 1,2-phenylene, 1,2-naphthylene or 3,4-naphthylene radicals. Preference is given to 1,2-phenylene or substituted 1,2-phenylene radicals of the general formula (V) or (Va)

at the radicals R and R 'act it - independently - around linear or branched alkyl groups having 1 to 12 C atoms, preferred to linear alkyl groups having 1 to 6 carbon atoms. Especially preferred these are methyl groups.

The Compounds of the invention (III) each exist in several different isomers. The residues OR or OR 'can in Cis or trans position may be located on the tetrahydrofuran ring. Correspondingly the O atoms of the -O-X-O unit in each case in the cis or trans position relative to each other or to the radicals OR or OR 'arranged be.

Prefers Compound (III) is 3,4-ethylenedioxy-2,5-dimethoxytetrahydrofuran (IIIa).

The Compounds of the invention (III) starting from 2,5-dialkoxydihydrofurans (I) are made. The radicals R and R 'have already been defined above.

at a preferred starting material is 2,5-dimethoxydihydrofuran (DMDH). DMDH is commercially available.

In a first synthesis step (A), the 2,5-dialkoxydihydrofuran (I) is reacted with a diol of the general formula HO-X-OH and with Cl ₂ and / or Br ₂ according to the general reaction scheme (A) X is an alkylene radical or an arylene radical as defined above. Here, the tetrahydrofuran derivative (II) is formed 2,5-dialkoxy-3-hydroxyalkoxy-4-chlorotetrahydrofuran, or the corresponding bromine-substituted and / or aryl-substituted products. Preferably, Cl _{2 is used} as a reactant.

at the diols HO-X-OH used can be alkylene diols 2 to 30 carbon atoms, preferably 2 to 12, more preferably 2 to 6 and most especially preferably 2 or 3 C atoms act.

at The alkylene diols may be, for example, 1, ω-alkylene diols act. Examples of such diols include ethylene glycol, 1,3-propylene glycol, 1,4-butylene glycol, 1,6-hexylene glycol or 1,12-dodecylene glycol. Examples of other suitable alkylene diols include linear 1,2-alkylene glycols such as, for example, 1,2-propylene glycol, 1,2-butylene glycol or cyclic diols such as 1,2-cyclopentanediol or 1,2-cyclohexanediol. To be favoured Ethylene glycol, 1,2-propylene glycol or 1,3-propylene glycol used, particularly preferably ethylene glycol.

Furthermore, it may be vic-Dihydroxyarylverbindungen having 6 to 30 carbon atoms, preferably 6 - 14 C-atoms act. Examples of suitable diols include dihydroxyaryl compounds, in particular 1,2-dihydroxybenzene or R ¹ -substituted 1,2-dihydroxybenzene.

The Reaction can be carried out by adding a mixture of 2,5-dialkoxydihydrofuran (I) with the desired Diol HO-X-OH in a suitable reaction vessel and presents chlorine gas passes the mixture.

Advantageous can be at liquid Diolen HO-X-OH a surplus of the alcohol are used. The diol then serves simultaneously as a solvent.

The Of course, reaction can be in the presence of an additional solvent be performed. Examples of suitable solvents include, for example, ethylene glycol dialkyl ethers or diethylene glycol dialkyl ethers.

The reaction is usually at a temperature of -20 ° C to + 40 ° C, without the invention should be limited to this area. Preferably, the temperature is -10 ° C to + 20 ° C and more preferably 0 to 5 ° C.

It is regularly recommended, the reaction in the presence of a soluble or solid basic compound perform. Suitable basic compounds are preferred selected by at least one base from the group of alkali metal hydroxides, carbonates, bicarbonates, Alkaline earth metal hydroxides, carbonates and bicarbonates. Particularly preferred is sodium bicarbonate.

The Amount of the base is chosen by the skilled person depending on the desired conditions. Has proven an amount of 1 to 5 mol, preferably 2 to 4 mol of the basic Connection regarding DMDH, without the invention being restricted thereto.

chlorine or bromine is advantageously used in a slight excess.

The Isolation of the formed Tetrahydrofuranderivates (II) can by means of conventional organic-chemical methods are made. The crude product can be purified after isolation by known methods, for example, with the aid of liquid chromatography.

The obtained tetrahydrofuran derivative (II) is in a second step of the synthesis (B) to the novel 3,4-alkylenedioxy-2,5-dialkoxy-tetrahydrofurans or 3,4-arylenedioxy-2,5-dialkoxy-tetrahydrofurans (III) implemented.

Of the Ring closure occurs via an intramolecular ether formation and is in the presence of a suitable Base made. Suitable bases are for example to alkali or alkaline earth metal hydroxides, such as NaOH or KOH or alkali or alkaline earth metal alcoholates, such as potassium tert-butoxide. Particularly preferred as the base is KOH.

Prefers the reaction is carried out in an organic solvent. suitable Solvents are for example, dimethyl sulfoxide, dimethylformamide or dimethylacetamide.

The Base can be in the solvent soluble or may be preferred in the course of the reaction to solid form be used finely powdered.

The Reaction is usually at a temperature of 40 ° C to 160 ° C, preferably 70 ° C to 140 ° C and particularly preferably carried out at 90 to 110 ° C.

The Isolation of the compounds of the invention (III) can by means of customary organic-chemical methods are made. The crude product can be purified after isolation by known methods, for example, with the aid of liquid chromatography.

At the Reaction Scheme B, the compounds of the invention are formed as a mixture of isomers. All certain isomers can isolated therefrom by methods known in principle to those skilled in the art become.

The Compounds of the invention (III) for the preparation of 3,4-alkylenedioxythiophenes or 3,4-arylenedioxythiophenes (IV) can be used. The production can be carried out by means of a one-step process according to synthesis scheme (C).

in this connection be the compounds of the invention (III) reacted with sulphidic sulfur in the presence of a strong acid.

Sulfidic sulfur can be hydrogen sulfide or salts thereof, ie, hydrogen sulfides or sulfides. Sulfides and hydrogen sulfides can be present in particular as alkali metal salts. Examples include Na ₂ S, NaHS or Na ₂ S ₂ .

Examples of suitable acids include mineral acids such as HCl, H ₂ SO ₄ , HNO ₃ or H ₃ PO ₄ . H ₂ SO ₄ and / or HNO ₃ are preferably used as dilute acids. Preference is given to HCl.

The Reaction can be carried out, for example, as a two-phase reaction, by reacting the starting compound (III) in a suitable, inert organic solvents solves. in this connection it may be, for example, inert aliphatic and / or aromatic Hydrocarbons, such as alkanes with appropriate Boiling point, or alkyl aromatics such as toluene or xylene act. For this Are the proposed organic solution, a suitable aqueous solution sulfidic Sulfur as well as the acid to. The acid can For example, added as a concentrated aqueous solution who the. The Implementation should take place with intimate mixing of the two phases, for example by means of an intensively acting stirrer.

The Reaction is usually at a temperature of 0 ° C to 100 ° C, preferably 20 ° C to 80 ° C and especially preferably at 40 to 60 ° C carried out.

The Isolation of the thiophene derivatives (IV) can be carried out by means of customary organic-chemical methods are made. The crude product can be purified after isolation by known methods, for example with the help of liquid chromatography.

at Use of compound (IIIa) as starting material can be by the synthesis step (C) very particularly elegant 3,4-ethylenedioxythiophene (EDOT). The synthetic route to EDOT using the Compounds of the invention (III) comprises only 3 stages and not 4 as in the known one Process for the preparation of EDOT.

In analogous way can be 3,4-alkylenedioxyselenophene or To produce 3,4-arylenedioxyselenophene, by substituting the sulfidic compounds for corresponding Se compounds starts.

Farther can Also 3,4-alkylenedioxypyrroles or 3,4-Arylendioxypyrrole produced be prepared by reacting the compounds (III) with amines, such as Reacting alkylamines or the corresponding amine hydrochlorides. This can be done in analogous application to that described in A. Merz, T. Meyer, Synthesis 1999, no. 1,94-99 Conditions are fulfilled. This initially produces an N-alkylpyrrole. The Alkyl group can also be cleaved under suitable conditions.

The The following examples are intended to explain the invention in more detail:

Example 1:

Preparation of the compound (II)

In a reaction vessel were 130.0 g (1.0 mol) Dimethoxydihydrofuran (DMDH) together with Dissolved 205.0 g (2.44 mol) of sodium bicarbonate in 400 ml of ethylene glycol and cooled to 5 ° C. Then 178 g (2.5 mol) of chlorine gas were introduced within one hour. After complete addition of chlorine was allowed to stir for 60 min at 5 ° C. The mixture was then warmed to room temperature and stirred for a further 2 hours at room temperature. Subsequently, it was mixed with 500 ml of water and extracted three times with 300 ml of methyl tert-butyl ether. The combined organic extracts were then dried over Na ₂ SO ₄ and freed from solvent on a rotary evaporator. There was obtained 151 g of a clear, pale yellow colored residue with a purity of 64 FI% GC. This corresponds to a yield of 42%. Further purification to 80% by volume GC was carried out by liquid chromatography on SiO ₂ using MTBE as solvent.

Example 2:

Preparation of the compound of the invention (III)

3.3 g (0.05 mol) of potassium hydroxide in 20 ml of dimethyl sulfoxide were placed in a reaction vessel. A solution of 4.5 g (80% = 0.016 mol) of the product (II) obtained in Example 1, dissolved in 20 ml of dimethyl sulfoxide, was added slowly with stirring. Thereafter, it was heated to 100 ° C for 3 h. After cooling, it was taken up in 100 ml of water and extracted twice with 70 ml of chloroform each time. The combined chloroform extracts were dried over Na ₂ SO ₄ and concentrated on a rotary evaporator. There were obtained 15 g of crude product which still contained 80% DMSO (GC-AnalSye). The compound (III) according to the invention, 3,4-ethylenedioxy-2,5-dimethoxy-tetrahydrofuran, was obtained as a mixture of isomers in 33% yield (FI% GC).

Example 3:

Use of 3,4-ethylenedioxy-2,5-dimethoxy-tetrahydrofuran (IIIa) for the production of EDOT

In a reaction vessel were 8.4 ml of water together with 16 ml of toluene and 11.2 g (0.12 mol) of conc. hydrochloric acid (37%) submitted. Then the apparatus was sealed. simultaneously were a solution of 15.7 g (63% = 0.052 mol) of 3,4-ethylenedioxy-2,5-dimethoxy-tetrahydrofuran in 20 ml of toluene and a solution of 11.2 g (30% NaSH = 0.06 mol) are added in 10 ml of water, so that the overpressure 20 mbar not exceeded. After dosing, the mixture was stirred at 60 ° C for 60 min. It was allowed to cool and led a phase separation by. The organic phase was first with a little 10% hydrochloric acid and then washed with 10% sodium bicarbonate solution. The watery Phases were extracted with dichloromethane. Finally were concentrated the combined organic extracts on a rotary evaporator. There were 5.5 g of a pale brown colored liquid with a purity obtained from 80% by volume GC. This corresponds to a yield of 60% EDOT.

Claims (13)

Compounds of the general formula (III)

wherein X is a linear or branched, substituted or unsubstituted alkylene radical having 2 to 30 carbon atoms or a substituted or unsubstituted arylene radical having 6 to 30 carbon atoms, and R and R 'independently of one another for linear or branched alkyl groups having 1 to 12 C atoms are. Compounds according to claim 1, characterized in that the radical X has 2 to 12 carbon atoms. Compounds according to claim 1, characterized in that X is an ethylene radical -CH ₂ -CH ₂ - or a substituted ethylene radical -CHR ¹ -CH ₂ -, wherein R ¹ is a radical selected from the group of linear or branched alkyl, aralkyl, aryl or alkylaryl radicals having 1 to 12 carbon atoms. Connection according to one the claims 1 to 3, characterized in that R and R 'are each methyl groups is. A compound according to claim 1, characterized in that it is 3,4-ethylenedioxy-2,5-dimethoxytetrahydrofuran (IIIa).

A process for the preparation of compounds of the general formula (III) comprising the following steps: (A) reaction of 2,5-dialkoxydihydrofurans with diols of the general formula HO-X-OH and Cl ₂ and / or Br ₂ , where X is a linear or branched, substituted or unsubstituted alkylene radical having 2 to 30 carbon atoms or a substituted or unsubstituted arylene radical having 6 to 30 carbon atoms, followed by (B) intramolecular cyclization of the reaction product formed in the presence of a base. Method according to claim 6, characterized in that the step (A) in the presence of a basic compound performs. Method according to claim 7, characterized in that it is in the basic compound selected by at least one from the group of alkali metal hydroxides, carbonates, bicarbonates, alkaline earth metal hydroxides, carbonates and bicarbonates. Method according to one the claims 6 to 8, characterized in that one stage (A) at a temperature from -20 ° C to + 40 ° C performs. Use of compounds of the general formula (III) for the preparation of 3,4-alkylenedioxythiophenes or 3,4-arylenedioxythiophenes. Use according to claim 10, characterized in that the compounds (III) with sulfidic sulfur in the presence of strong acids. Use of compounds of the general formula (III) for the preparation of 3,4-alkylenedioxyselenophenes or 3,4-arylenedioxyselenophenes. Use of compounds of the general formula (III) for the preparation of 3,4-alkylenedioxypyrroles or 3,4-arylenedioxypyrroles.