Method for producing materials for use in electronic devices

Abstract

The invention relates to a method for producing indolo[3,2,1-jk]carbazole and derivatives by reacting a compound of formula (1) and at least one nitrosyl cation source.

Description

[0001] Process for producing materials for use in electronic devices

[0002] The present invention relates to processes, in particular for the preparation of materials for use in electronic devices, in particular in organic electroluminescent devices.

[0003] Electronic devices containing organic, organometallic, and / or polymeric semiconductors are becoming increasingly important. Due to their cost and performance, these semiconductors are used in many commercial products. Examples include organic-based charge transport materials (e.g., triarylamine-based hole transporters) in copiers, organic or polymeric light-emitting diodes (OLEDs or PLEDs) in display devices, and organic photoreceptors in copiers. Organic solar cells (O-SCs), organic field-effect transistors (O-FETs), organic thin-film transistors (O-TFTs), organic switching elements (O-ICs), organic optical amplifiers, and organic laser diodes (O-lasers) are at an advanced stage of development and have the potential to become highly important in the future.

[0004] Electronic devices within the meaning of this invention are understood to be organic electronic devices that contain organic semiconductor materials as functional materials. In particular, the electronic devices represent electroluminescent devices such as OLEDs.

[0005] The structure of OLEDs, which use organic compounds as functional materials, is known to those skilled in the art. Generally, OLEDs are electronic devices that have one or more layers comprising organic compounds and emit light when a voltage is applied.

[0006] In electronic devices, especially OLEDs, there is a great need to improve performance, particularly lifetime, efficiency, and operating voltage. No satisfactory solution has yet been found for these aspects.

[0007] Electronic devices typically comprise a cathode, an anode, and at least one functional, preferably emissive, layer. In addition to these layers, they may contain further layers, for example, one or more hole-injection layers, hole-transport layers, hole-blocking layers, electron-transport layers, electron-injection layers, exciton-blocking layers, electron-blocking layers, and / or charge-generation layers.

[0008] The hole transport layers and electron transport layers have a major influence on the performance of electronic devices.

[0009] Indolo[3,2,1-jk]carbazole is a very important structural unit in such materials, especially in e- and h-TMM (electron-conducting or hole-conducting tandem matrix materials), narrowband SEB (blue singlet emitter), HTM (hole-transport materials) and EBM (electron-blocking materials).

[0010] In the known processes, the second ring is closed starting with an N-arylated carbazole. This makes it impossible to control the regioisomers, as the ring can be closed with either of the two six-membered rings of the carbazole.

[0011]

[0012] Depending on the ring closure reaction, X' can represent H or a corresponding reactive group.

[0013] Known ring-closing reactions include pyrolysis (Wharton et al., Chem. Eur. J. 15 (2009) 5482), oxidative cyclization (Jones et al., Adv. Synth. Catal. 357 (2015) 945), transition metal catalysis (Lv et al., Tetrahedron Letters 53 (2012) 5248) and diazotization (Hiraga et al., Tetrahedron 94 (2021) 132317; Hiraga et al., Tetrahedron 86 (2021) 132049).

[0014] However, the yields are often low and the reaction conditions often do not allow for additional groups.

[0015] Pyrolysis is complex in terms of equipment and requires extreme conditions. It is also only applicable to vaporizable groups.

[0016] Transition metal catalysis often requires high temperatures and long reaction times, as well as the use of transition metals. Low to no regioselectivity is observed. Large catalyst loadings are often required. Diazotization has been reported to produce low yields and show little to no regioselectivity.

[0017] Chatterjee et al., Org. Lett. 19 (2017) 1906, reported the preparation of carbazoles by a light-catalyzed intramolecular ring closure reaction from a biphenyldiamine in the presence of t-BuONO in an oxygen atmosphere. The reaction requires an oxygen atmosphere and intensive light exposure. Only low yields were achieved, and higher reaction temperatures did not improve yields.

[0018] The object of the present invention is to provide a process for the preparation of indolo[3,2,1-jk]carbazole and derivatives thereof.

[0019] The present invention therefore provides a process for the preparation of indolo[3,2,1-jk]carbazole and derivatives thereof comprising the following steps: a) providing a composition comprising a compound of formula (1) and at least one nitrosyl cation source; b) converting the composition from a) to a diazonium salt; c) optionally isolating the diazonium salt according to formula (2); d) converting to a compound according to formula (3); and wherein the symbols used are:

[0020] Ar 1 , Ar 2 , Ar 3are, identically or differently at each occurrence, an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which may be substituted by one or more radicals R, where two or more R may together form an aromatic or heteroaromatic ring system;

[0021] Y 1 , Y 2 are, identical or different at each occurrence, a single bond, S, CO, O, NR, BR, C=CR2, CR2, SO2, SiR2, GeR2, P(O)R, Se or Te;

[0022] R is the same or different at each occurrence and is H, D, F, CI, Br, I, OAr', N(R 1 )2, N(Ar')2, SAr', B(OR 1 )2, CHO, C(=O)R 1 , CR 1 =C(R 1 )2, CN, C(=O)OR 1 , C(=O)NR 1 , Si(R 1 )3, NO2, P(=O)(R 1 )2, OSO2R 1 , OR 1 , S(=O)R 1 , S(=O)2R 1 , SR 1, a straight-chain alkyl group having 1 to 20 C atoms or an alkenyl or alkynyl group having 2 to 20 C atoms or a branched or cyclic alkyl group having 3 to 20 C atoms, wherein the alkyl, alkenyl or alkynyl group is each substituted by one or more radicals R 1 may be substituted, with one or more non-adjacent CH2 groups being replaced by -R 1 C=CR 1 -, - S-, SO or SO2, or an aromatic or heteroaromatic ring system with 5 to 60 aromatic ring atoms, preferably with 5 to 40 aromatic ring atoms, each substituted by one or more radicals R 1 may be substituted, where two or more R radicals preferably bound to the same cycle may form an aliphatic, heteroaliphatic, aromatic or heteroaromatic ring system which may be substituted with one or more R radicals 1 can be substituted;

[0023] Ar' is at each occurrence, identically or differently, an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which is substituted by one or more radicals R 1 may be substituted, where two or more R 1 can form an aromatic or heteroaromatic ring system with each other;

[0024] R 1 is the same or different at each occurrence H, D, F, I, B(OR 2 )2, CHO, C(=O)R 2 , CR 2 =C(R 2 )2, CN, C(=O)OR 2 , Si(R 2 )3, NO2, P(=O)(R 2 )2, OSO2R 2 , SR 2 , OR 2 , N(R 2 )2, S(=O)R 2 , S(=O)2R 2 , a straight-chain alkyl group having 1 to 20 C atoms or an alkenyl or alkynyl group having 2 to 20 C atoms or a branched or cyclic alkyl group having 3 to 20 C atoms, wherein the alkyl, alkenyl or alkynyl group is each substituted by one or more radicals R 2and wherein one or more CH2 groups in the above-mentioned groups are substituted by -R 2 C=CR 2 -, -CEC-, Si(R 2 )2, C=O, C=S, -C(=O)O-, NR 2 , CONR 2 , P(=O)(R 2 ), -O-, -S-, SO or SO2 and where one or more H atoms in the above-mentioned groups can be replaced by D, F, CI, Br, I, CN or NO2, or an aromatic or heteroaromatic ring system with 5 to 30 aromatic ring atoms, each of which is substituted by one or more radicals R 2 may be substituted, where two or more radicals R 1 can form an aliphatic, heteroaliphatic, aromatic or heteroaromatic ring system; R 2is, identically or differently at each occurrence, H, D, F, CN or an aliphatic, aromatic or heteroaromatic organic radical having 1 to 20 C atoms, in which one or more H atoms may be replaced by D or F; two or more substituents R 2 be linked together and form a ring;

[0025] Z" is an anion, preferably from the nitrosyl cation source.

[0026] In a preferred embodiment of the invention, Ar 1 , Ar 2 and Ar 3 at each occurrence, identically or differently, denotes an aryl or heteroaryl group having 6 to 13 aromatic ring atoms or a fluorene group, where the aryl or heteroaryl groups or the fluorene group may each be substituted by one or more radicals R. Particular preference is given to Ar 1 , Ar 2 and Ar 3at each occurrence, identically or differently, an aryl group having 6 to 10 aromatic ring atoms or a heteroaryl group having 6 to 13 aromatic ring atoms or a fluorene group, where the aryl or heteroaryl groups or the fluorene group may each be substituted by one or more radicals R. Very particular preference is given to Ar 1 , Ar 2 and Ar 3 at each occurrence, identically or differently, phenyl, naphthyl, fluorene, dibenzofuran, dibenzothiophene, carbazole, azadibenzofuran or diazadibenzofuran. Particular preference is given to Ar 1 , Ar 2 and Ar 3 at each occurrence, identically or differently, denote phenyl, dibenzofuran or carbazole, where preferably at least two of the groups Ar 1 , Ar 2 and Ar 3 stand for phenyl.

[0027] In a preferred embodiment of the invention, the compounds of formulas (1), (2) and (3) are compounds of formula (1-1), (2-1) and (3-1):

[0028] Formula (3-1) where additionally:

[0029] X is the same or different at each occurrence CR or N with the proviso that a maximum of two groups X per cycle represent N;

[0030] It is also possible for the compound of formula (1) or (1-1) to have more than one structural unit for carrying out the reaction according to the invention. This makes it possible to produce more complex structures in one step by multiple ring closures. Compounds with one, two, or three, preferably one or two, structural units are preferred for carrying out the reaction according to the invention. Examples of such a structure with two structural units are, for example, the following structures of formula (1a), (2a), or (3a):

[0031] The symbols used correspond to the symbols of formula (1), (2), and (3), respectively, and the preferred embodiments also correspond to the preferred embodiments of formula (1), (2), and (3), respectively. The bond between the two six-membered rings containing N and Y 1 on Ar 3 be either cis- or trans-positioned, as shown below for formula (3a):

[0032] For formulas (1a), (2a) and (3a) the same preferences apply for Ar 1 , Ar 2 , Ar 3 , Y 1 and Y 2 , as described above.

[0033] Preferred compounds with two structural units are compounds of the formula (1-1 a), (2-1 a) and (3-1 a):

[0034] Formula (1-1 a) Formula (2-1 a)

[0035] Formula (3-1 a)

[0036] The symbols used correspond to the symbols of the formula (1-1), (2-1) and (3-1) respectively.

[0037] Analogously, the compounds of the following formulas (1-1 b) to (1-1 h) can be converted to the compounds of the following formulas (3-1 b) to (3-1 h):

[0038] The symbols used have the meanings mentioned above.

[0039] An aryl group within the meaning of this invention contains 6 to 40 C atoms; a heteroaryl group within the meaning of this invention contains 5 to 40 C atoms and at least one heteroatom, with the proviso that the sum of C atoms and heteroatoms is at least 5. The heteroatoms are preferably selected from N, O and / or S. An aryl group or heteroaryl group is understood to be either a simple aromatic ring, i.e. benzene, or a simple heteroaromatic ring, for example pyridine, pyrimidine, thiophene, etc., or a condensed (fused) aryl or heteroaryl group, for example naphthalene, anthracene, phenanthrene, quinoline, isoquinoline, etc. Aromatics linked to one another by a single bond, such as biphenyl, are not referred to as aryl or heteroaryl groups, but as an aromatic ring system.

[0040] An aromatic ring system within the meaning of this invention contains 6 to 60 C atoms, preferably 6 to 40 C atoms in the ring system. A heteroaromatic ring system within the meaning of this invention contains 1 to 60 C atoms, preferably 1 to 40 C atoms and at least one heteroatom in the ring system, with the proviso that the sum of C atoms and heteroatoms is at least 5. The heteroatoms are preferably selected from N, O and / or S. An aromatic or heteroaromatic ring system within the meaning of this invention is to be understood as a system that does not necessarily contain only aryl or heteroaryl groups, but in which several aryl or heteroaryl groups can also be linked by a non-aromatic unit (preferably less than 10% of the atoms other than H), such as a C, N or O atom or carbonyl group. This also includes systems in which two or more aryl or heteroaryl groups are directly linked to one another, such as:Biphenyl, terphenyl, bipyridine, or phenylpyridine. For example, systems such as fluorene, 9,9'-spirobifluorene, 9,9-diarylfluorene, triarylamine, diaryl ether, stilbene, etc. are also to be understood as aromatic ring systems within the meaning of this invention, as are systems in which two or more aryl groups are linked, for example, by a linear or cyclic alkyl group or by a silyl group. Preferred aromatic or heteroaromatic ring systems are simple aryl or heteroaryl groups, as well as groups in which two or more aryl or heteroaryl groups are directly linked to one another, for example biphenyl, terphenyl, quaterphenyl, or bipyridine, as well as fluorene or spirobifluorene.

[0041] An electron-rich heteroaromatic ring system is characterized by the fact that it is a heteroaromatic ring system that contains no electron-deficient heteroaryl groups. An electron-deficient heteroaryl group is a six-membered ring heteroaryl group with at least one nitrogen atom or a five-membered ring heteroaryl group with at least two heteroatoms, one of which is a nitrogen atom and the other oxygen, sulfur, or a substituted nitrogen atom, to which further aryl or heteroaryl groups may be fused. In contrast, electron-rich heteroaryl groups are five-membered ring heteroaryl groups with exactly one heteroatom selected from oxygen, sulfur, or substituted nitrogen, to which further aryl groups and / or further electron-rich five-membered ring heteroaryl groups may be fused.Examples of electron-rich heteroaryl groups include pyrrole, furan, thiophene, indole, benzofuran, benzothiophene, carbazole, dibenzofuran, dibenzothiophene, or indenocarbazole. An electron-rich heteroaryl group is also referred to as an electron-rich heteroaromatic radical. An electron-poor heteroaromatic ring system is characterized by containing at least one electron-poor heteroaryl group and, particularly preferably, no electron-rich heteroaryl groups.

[0042] In the context of the present invention, the term "alkyl group" is used as a generic term for both linear or branched alkyl groups and cyclic alkyl groups. Analogously, the terms "alkenyl group" and "alkynyl group" are used as generic terms for both linear or branched alkenyl or alkynyl groups, as well as for cyclic alkenyl or alkynyl groups.

[0043] A cyclic alkyl, alkoxy or thioalkoxy group in the sense of this invention is understood to mean a monocyclic, a bicyclic, a tricyclic or a polycyclic group.

[0044] In the context of the present invention, an aliphatic hydrocarbon radical or an alkyl group or an alkenyl or alkynyl group which may contain 1 to 40 C atoms and in which individual H atoms or CH2 groups may be substituted by the above-mentioned groups, preferably the radicals methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, s-butyl, t-butyl, 2-methylbutyl, n-pentyl, s-pentyl, t-pentyl, 2-pentyl, neo-pentyl, cyclopentyl, n-hexyl, s-hexyl, t-hexyl, 2-hexyl, 3-hexyl, neo-hexyl, cyclohexyl, 1-methylcyclopentyl, 2-methylpentyl, n-heptyl, 2-heptyl, 3-heptyl, 4-heptyl, cycloheptyl, 1-methylcyclo-hexyl, n-octyl, cyclooctyl, 2-ethylhexyl, 1-bicyclo[2,2,2]octyl, 2-bicyclo[2,2,2]octyl, 2-(2,6-dimethyl)octyl, 3-(3,7-Dimethyl)octyl, adamantyl, trifluoromethyl, pentafluoroethyl, 2,2,2-trifluoroethyl, 1 , 1 -dimethyl-n-hex-1 -yl, 1 , 1 -dimethyl-n-hept-1 -yl, 1 , 1 -dimethyl-n-oct-1 -yl, 1 , 1 -dimethyl-n-dec-1 -yl, 1 , 1-Dimethyl-n-dodec-1-yl,1 , 1 -Dimethyl-n-tetradec-1 -yl, 1 , 1 -Dimethyl-n- hexadec-1 -yl, 1 ,1 -Dimethyl-n-octadec-1 -yl, 1 , 1 -Diethyl-n-hex-1 -yl, 1 ,1 - Diethyl-n-hept-1 -yl, 1 , 1 -Diethyl-n-oct-1 -yl, 1 , 1 -Diethyl-n-dec-1 -yl, 1 ,1 - Diethyl-n-dodec-1 -yl, 1 , 1 -Diethyl-n-tetradec-1 -yl, 1 , 1 -Diethyl-n-hexadec-1 - yl, 1 ,1 -Diethyl-n-octadec-1 -yl, 1 -(n-Propyl)-cyclohex-1 -yl, l -(n-Butyl)- cyclohex-1 -yl, 1 -(n-Hexyl)-cyclohex-1 -yl, 1 -(n-Octyl)-cyclohex-l -yl und 1 - (n-Decyl)-cyclohex-l -yl, Ethenyl, Propenyl, Butenyl, Pentenyl, Cyclo- pentenyl, Hexenyl, Cyclohexenyl, Heptenyl, Cycloheptenyl, Octenyl, Cyclooctenyl, Cyclooctadienyl, Ethinyl, Propinyl, Butinyl, Pentinyl, Hexinyl, Heptinyl oder Octinyl verstanden. Unter einer Alkoxygruppe OR, 1mit 1 bis 40 C-Atomen werden bevorzugt Methoxy, Trifluormethoxy, Ethoxy, n-Propoxy, i-Propoxy, n-Butoxy, i-Butoxy, s-Butoxy, t-Butoxy, n-Pentoxy, s-Pentoxy, 2-Methylbutoxy, n-Hexoxy, Cyclohexyloxy, n-Heptoxy, Cyclo- heptyloxy, n-Octyloxy, Cyclooctyloxy, 2-Ethylhexyloxy, Pentafluorethoxy und 2,2, 2-Trifluorethoxy verstanden. Unter einer Thioalkylgruppe SR 1mit 1 bis 40 C-Atomen werden insbesondere Methylthio, Ethylthio, n-Propyl- thio, i-Propylthio, n-Butylthio, i-Butylthio, s-Butylthio, t-Butylthio, n-Pentyl- thio, s-Pentylthio, n-Hexylthio, Cyclohexylthio, n-Heptylthio, Cycloheptyl- thio, n-Octylthio, Cyclooctylthio, 2-Ethylhexylthio, Trifluormethylthio, Pentafluorethylthio, 2,2,2-Trifluorethylthio, Ethenylthio, Propenylthio, Butenylthio, Pentenylthio, Cyclopentenylthio, Hexenylthio, Cyclohexenyl- thio, Heptenylthio, Cycloheptenylthio, Octenylthio, Cyclooctenylthio, Ethinylthio, Propinylthio, Butinylthio, Pentinylthio, Hexinylthio, Heptinylthio oder Octinylthio verstanden.In general, alkyl, alkoxy, or thioalkyl groups according to the present invention may be straight-chain, branched, or cyclic, wherein one or more non-adjacent CH2 groups may be replaced by the above-mentioned groups; furthermore, one or more H atoms may be replaced by D, F, Cl, Br, I, CN, or NO2, preferably F, Cl, or CN, particularly preferably F or CN.

[0045] An aromatic or heteroaromatic ring system with 5 - 60 aromatic ring atoms, preferably 5 - 40 aromatic ring atoms, which may also be substituted by the above-mentioned radicals or a hydrocarbon radical and which may be linked to the aromatic or heteroaromatic ring via any desired positions, is understood to mean, in particular, groups derived from benzene, naphthalene, anthracene, benzanthracene, phenanthrene, pyrene, chrysene, perylene, fluoranthene, naphthacene, pentacene, benzopyrene, biphenyl, biphenylene, terphenyl, triphenylene, fluorene, spirobifluorene, dihydrophenanthrene, dihydropyrene, tetrahydropyrene, cis- or trans-indenofluorene, cis- or trans-indenocarbazole, cis- or trans-indolocarbazole, cis- or trans-monobenzoindenofluorene, cis- or trans-dibenzoindenofluorene, Truxene, isotruxene, spirotruxene, spiroisotruxene, furan, benzofuran, isobenzofuran, dibenzofuran, thiophene, benzothiophene, isobenzothiophene, dibenzothiophene, pyrrole,Indol, Isoindol, Carba- zol, Pyridin, Chinolin, Isochinolin, Acridin, Phenanthridin, Benzo-5,6-chino- lin, Benzo-6,7-chinolin, Benzo-7,8-chinolin, Phenothiazin, Phenoxazin, Pyrazol, Indazol, Imidazol, Benzimidazol, Naphthimidazol, Phenanthrimi- dazol, Pyridimidazol, Pyrazinimidazol, Chinoxalinimidazol, Oxazol, Benz- oxazol, Naphthoxazol, Anthroxazol, Phenanthroxazol, Isoxazol, 1 ,2- Thiazol, 1 ,3-Thiazol, Benzothiazol, Pyridazin, Hexaazatriphenylen, Benzo- pyridazin, Pyrimidin, Benzpyrimidin, Chinoxalin, 1 ,5-Diazaanthracen, 2,7- Diazapyren, 2,3-Diazapyren, 1 ,6-Diazapyren, 1 ,8-Diazapyren, 4,5-Diaza- pyren, 4,5,9, 10-Tetraazaperylen, Pyrazin, Phenazin, Phenoxazin, Pheno- thiazin, Fluorubin, Naphthyridin, Azacarbazol, Benzocarbolin, Phenan- throlin, 1 ,2,3-Triazol, 1 ,2,4-Triazol, Benzotriazol, 1 ,2,3-Oxadiazol, 1 ,2,4- Oxadiazol, 1 ,2,5-Oxadiazol, 1 ,3,4-Oxadiazol, 1 ,2,3-Thiadiazol, 1 ,2,4-Thia- diazol, 1 ,2,5-Thiadiazol, 1 ,3,4-Thiadiazol, 1 ,3,5-Triazin, 1 ,2,4-Triazin, 1 ,2,3-Triazine, Tetrazole, 1,2,4,5-tetrazine, 1,2,3,4-tetrazine, 1,2,3,5-tetrazine, purine, pteridine, indolizine and benzothiadiazole or groups derived from combinations of these systems.

[0046] For the purposes of this description, the phrase "two or more residues can form a ring system" is understood to mean, among other things, that the two residues are linked by a chemical bond with the formal elimination of two hydrogen atoms. This is illustrated by the following scheme:

[0047] In education

[0048] Furthermore, the above formulation should also be understood to mean that if one of the two residues represents hydrogen, the second residue binds to the position to which the hydrogen atom was bonded, forming a ring. This is illustrated by the following scheme:

[0049] In a first step, a composition comprising a compound of formula (1) and at least one nitrosyl cation source is provided.

[0050] A nitrosyl cation source is defined as a compound or combination of compounds that releases nitrosyl cations under the reaction conditions. The nitrosyl cation can be already present in the source, as in the case of a nitrosyl salt, or it can be generated in situ, as in the case of a nitrite compound with an acid.

[0051] Preferably, the nitrosyl cation source is soluble in the composition.

[0052] In a preferred embodiment, the nitrosyl cation source is selected from at least one nitrosyl salt and / or the combination of a nitrite compound with an acid, preferably at least one nitrosyl salt and / or the combination of an organic nitrite compound with an acid. The acid is preferably a protic acid compound. This allows the nitrosyl cation to be formed by elimination of water and / or alcohol.

[0053] Examples of nitrosyl salts are nitrosyl fluoride, nitrosyl chloride, nitrosyl bromide, nitrosyl cyanide, nitrosyl azide, nitrosyl perchlorate, nitrosyl perfluoroborate, and nitrosyl hexafluorophosphate. The use of nitrosyl salts avoids the use of an acid, allowing the presence of acid-labile groups in the compound of formula (1).

[0054] Examples of nitrite compounds are inorganic nitrite salts, such as sodium nitrite, potassium nitrite, or ammonium nitrite. Organic nitrite compounds, in particular alkyl nitrites (nitrous acid esters), are preferred, preferably selected from ethyl nitrite, propyl nitrite, isopropyl nitrite, 1-butyl nitrite, tert-butyl nitrite, amyl nitrite, or iso-amyl nitrite.

[0055] Nitrite compounds release nitrosyl cations in the presence of an acid. The acid is preferably a protic acid compound, such as nitric acid, sulfuric acid, hydrochloric acid, glacial acetic acid, trifluoroacetic acid, toluenesulfonic acid, especially anhydrous or as monohydrate, trifluoromethanesulfonic acid, tetrafluoroboric acid, or ammonium salts, such as ammonium tetrafluoroborate. Profaned complexes of these acids with, for example, diethyl ether can also be used. Examples of suitable compounds are oxonium ions HOR'2. +, where R' is identical or different and represents H, an alkyl group, or an aryl group, as defined above. Preferably, R' is identical or different at each occurrence and represents H or a straight-chain, branched, or cyclic alkyl group having 1 to 20 carbon atoms.

[0056] The composition preferably comprises at least one organic solvent, preferably a polar solvent, particularly preferably acetonitrile, dichloromethane, tetrahydrofuran, 1,4-dioxane, dimethylformamide, dimethyl sulfoxide, dimethylacetamide, methanol, ethanol, n-propanol, isopropanol, diethyl ether, tert-butyl methyl ether or tert-butyl ethyl ether, particularly preferably dichloromethane.

[0057] Preferably, the composition is a solution of the compound of formula (1).

[0058] The concentration can be adjusted depending on the reactants and the solvent. A concentration of the compound according to formula (1) of up to 10 mmol / L, preferably up to 5 mmol / L, is preferred.

[0059] In a preferred embodiment of the invention, the at least one nitrosyl cation source is added to the compound of formula (1). In a preferred embodiment, the nitrosyl cation source is added at a temperature below 10°C, in particular below 8°C, particularly preferably below 5°C. The temperature is selected such that the composition can still be stirred. A temperature of -10 to 5°C is preferred, particularly preferably 0°C.

[0060] In the case of a combination of acid and nitrite compound, the acid is preferably added first, followed by the nitrite compound. Preferably, at least the nitrite compound is added at the temperatures mentioned above; particularly preferably, both the acid and the nitrite compound are added at the temperatures mentioned above.

[0061] The nitrosyl cation source is preferably added while stirring the composition. In the case of a solution, the addition is carried out dropwise. In the case of a solid, such as nitrosyl salts, the addition is preferably carried out in several portions.

[0062] After each addition, it may be advantageous to stir the composition for 5 minutes to 2 hours, preferably at the same temperature as at the time of addition.

[0063] In a preferred embodiment, the nitrosyl cation source is added to the compound of formula (1) in an equimolar amount or in excess, based on the nitrosyl cations, preferably at least 1 equivalent, more preferably at least 1.01 equivalent, in particular at least 1.02 equivalent. 1.02 to 1.1 equivalents are particularly preferred. If the compound of formula (1) has multiple amino groups for diazotization, the equivalents refer to the number of amino groups for diazotization present in the compound of formula (1).

[0064] In the case of a nitrite compound, the equivalents refer to the nitrite compound. The acid is preferably added in at least equimolar amounts, in particular at least 1.02 equivalents, especially at least 1.5 equivalents, very particularly at least 2 equivalents, based on the amino groups for diazotization in the compound of formula (1). It may be necessary to adjust the amount of acid so that after protonation of the compound of formula (1), at least 1 equivalent of protons is still available for protonation of the nitrite compound.

[0065] The reaction in step a) is preferably carried out under a protective gas, preferably nitrogen or argon. A low-oxygen to oxygen-free atmosphere is preferred. This means an oxygen content of preferably less than 10 vol.%, in particular less than 5 vol.%, most preferably less than 1 vol.%.

[0066] In the case of nitrosyl salts as the nitrosyl cation source, the reaction is preferably carried out using dried reactants and solvents. In the case of nitrite compounds, especially inorganic nitrite salts, the reaction can also be carried out in the presence of water. For example, hydrates of the acids or aqueous solutions of the acids, e.g., HBF4 as a 30% aqueous solution, can be used. It might then also be possible to carry out the reaction with an aqueous and an organic phase.

[0067] The process is preferably carried out without exposure to light, meaning that no specific illumination of the reaction vessel is used. This allows the reaction to be carried out in an opaque vessel. The cleavage of the diazonium salt occurs upon heating.

[0068] The reaction is preferably carried out under normal pressure.

[0069] Optionally, the resulting diazonium salt of formula (2) can be isolated. Depending on the nitrosyl cation source, the anion Z is preferably the anion of the nitrosyl salt or the anion of the acid used.

[0070] When isolating the diazonium salt, the solvent for the composition in step c) can also be changed. The solvent is preferably selected from the solvents for step a). For the ring-closure reaction, a composition comprising a compound of formula (2) is provided. This can be achieved by dissolving a compound of formula (2) or by the reaction in step a).

[0071] In a preferred embodiment, the composition is added at a temperature below 10°C, in particular below 8°C, particularly preferably below 5°C. The temperature is selected such that the composition can still be stirred. A temperature of -10°C to 5°C is preferred, particularly preferably 0°C.

[0072] The composition is then converted to a compound of formula (3). Nitrogen is released during this process. This is preferably done by heating the composition relative to the temperature in step a). The heating can be controlled according to the nitrogen evolution. The temperature difference from step a) is preferably at least 10 °C.

[0073] Heating to at least 20°C is preferred, preferably to at least 30°C. Heating to up to 200°C, preferably up to 150°C, particularly preferably up to 100°C is particularly preferred.

[0074] Heating to 20 °C to 200 °C, in particular 20 °C to 150 °C, very particularly 20 °C to 100 °C, in particular 20 °C to 60 °C is particularly preferred.

[0075] The degree of conversion can be determined by measuring the amount of nitrogen released. The conversion is preferably carried out until a molar amount of nitrogen corresponding to at least 80%, in particular at least 90%, and most preferably at least 95%, based on the molar amount of the reactant has been released.

[0076] The reaction is preferably carried out until the release of nitrogen is complete. The release of nitrogen can be modulated by controlling the temperature.

[0077] The reaction in step c) is preferably carried out under a protective gas, preferably nitrogen or argon. An oxygen-free atmosphere is preferred. A low-oxygen to oxygen-free atmosphere is preferred. This means an oxygen content of preferably less than 10 vol.%, in particular less than 5 vol.%, most preferably less than 1 vol.%.

[0078] The reaction is preferably carried out using dried reactants and solvents.

[0079] The reaction is preferably carried out under pressure equalization with the environment.

[0080] The resulting product of formula (3) is preferably isolated. This can be done by precipitation, extraction, and / or solvent removal. The resulting solid can be washed and dried. Furthermore, the product can be further purified by standard methods of organic chemistry, for example, recrystallization, chromatography, and / or sublimation.

[0081] The conversion of the compound of formula (1) to formula (3) is preferably carried out to at least 60% up to quantitative yield based on the molarity.

[0082] The process according to the invention allows the preparation of the indolo-[3,2,1-jk]carbazole framework in high regioselectivity, under mild conditions and in high yields.

[0083] In a preferred embodiment, Y 1 and Y 2 selected from the following combinations:

[0084]

[0085]

[0086]

[0087]

[0088] In a preferred embodiment, a maximum of two X groups represent N and all further X groups represent CR, particularly preferably in combination with the embodiments of the table above. Particularly preferably, a maximum of one X group represents N and very particularly preferably all X groups represent CR, particularly preferably in combination with the embodiments of the table above.

[0089] In a preferred embodiment of the invention, Y 1 represents a single bond, BR, CR2, CO, N or O, particularly preferably a single bond, BR, N or O. In a further preferred embodiment of the invention, Y 2 for a single bond, BR, CR2, CO, N or O, particularly preferably for a single bond, BR, N or O and most preferably for a single bond.

[0090] In a particularly preferred embodiment, Y 1 and Y 2 selected from the following combinations:

[0091] In a preferred embodiment, a maximum of two X groups represent N and all further X groups represent CR, particularly preferably in combination with the embodiments of the table above. Particularly preferably, a maximum of one X group represents N, and very particularly preferably, all X groups represent CR, particularly preferably in combination with the embodiments of the table above.

[0092] Particularly preferred combinations of Y 1 and Y 2 are the combinations listed in the following table:

[0093] In a preferred embodiment, a maximum of two X groups represent N and all further X groups represent CR, particularly preferably in combination with the embodiments of the table above. Particularly preferably, a maximum of one X group represents N and very particularly preferably all X groups represent CR, particularly preferably in combination with the embodiments of the table above.

[0094] In the following, preferred substituents R, Ar', R 1 and R 2 In a particularly preferred embodiment of the invention, the following preferences for R, Ar', R 1 and R 2 simultaneously and apply to the structures of formula (1 ) as well as to all preferred embodiments listed above.

[0095] In a preferred embodiment of the invention, R is selected on each occurrence, identically or differently, from the group consisting of H, D, F, CN, OR 1, a straight-chain alkyl group having 1 to 10 C atoms or an alkenyl group having 2 to 10 C atoms or a branched or cyclic alkyl group having 3 to 10 C atoms, wherein the alkyl or alkenyl group is each substituted by one or more radicals R 1 may be substituted, but is preferably unsubstituted, and wherein one or more non-adjacent CH2 groups may be replaced by O, or an aromatic or heteroaromatic ring system having 6 to 30 aromatic ring atoms, each substituted by one or more radicals R 1may be substituted; two radicals R can also form an aliphatic, aromatic or heteroaromatic ring system with each other. Particularly preferably, R is selected, identically or differently at each occurrence, from the group consisting of H, F, CN, a straight-chain alkyl group having 1 to 6 C atoms, in particular having 1, 2, 3 or 4 C atoms, or a branched or cyclic alkyl group having 3 to 6 C atoms, where the alkyl group is substituted in each case with one or more radicals R 1 may be substituted, but is preferably unsubstituted, or an aromatic or heteroaromatic ring system having 6 to 24 aromatic ring atoms, each substituted by one or more radicals R 1 , preferably non-aromatic residues R 1, may be substituted. Very particularly preferably, R is selected at each occurrence, identically or differently, from the group consisting of H or an aromatic or heteroaromatic ring system having 6 to 24 aromatic ring atoms, each substituted by one or more radicals R 2 , preferably non-aromatic residues R 2 , can be substituted.

[0096] Suitable aromatic or heteroaromatic ring systems R are selected from phenyl, biphenyl, in particular ortho-, meta- or para-biphenyl, terphenyl, in particular ortho-, meta-, para- or branched terphenyl, quaterphenyl, in particular ortho-, meta-, para- or branched quaterphenyl, fluorene, which can be linked via the 1-, 2-, 3- or 4-position, spirobifluorene, which can be linked via the 1-, 2-, 3- or 4-position, naphthalene, which can be linked via the 1- or 2-position, indole, benzofuran, benzothiophene, which can be linked via the 1-, 2-, 3- or 4-position, dibenzofuran, carbazole, which can be linked via the 1-, 2-, 3- or 4-position, dibenzothiophene, which can be linked via the 1-, 2-, 3- or 4-position can, indenocarbazole, indolocarbazole, pyridine, pyrimidine, pyrazine, pyridazine, triazine, quinoline, quinazoline, benzimidazole, phenanthrene, triphenylene or a combination of two or three of these groups,which are each substituted with one or more radicals R, 1 may be substituted. If R represents a heteroaryl group, in particular triazine, pyrimidine or quinazoline, aromatic or heteroaromatic radicals R 1 at this heteroaryl group may be preferred.

[0097] The groups R, when they represent an aromatic or heteroaromatic ring system, are preferably selected from the groups of the following formulas R-1 to R-166,

[0098] R-19 R-20 R-21 - where R 1 has the meanings given above, the dashed bond represents the bond to formula (1 ) and furthermore:

[0099] Ar 3is at each occurrence, identically or differently, a bivalent aromatic or heteroaromatic ring system having 6 to 18 aromatic ring atoms, each of which is substituted by one or more radicals R 1 can be substituted;

[0100] A 1 is the same or different each time it occurs BR 1 , C(R 1 )2, NR 1 , 0 or S, preferably C(R 1 )2, 0 or S;

[0101] A 2 is the same or different at each occurrence C(R 1 )2, NR 1 , 0 or S; p is 0 or 1 , where p = 0 means that the group Ar 3 is not present and that the corresponding aromatic or heteroaromatic group is directly bonded to the corresponding atom, for example a carbon atom or to a heteroatom such as nitrogen. r is 0 or 1 , where r = 0 means that no group A is present at this position. 1and the corresponding carbon atoms are instead bound to residues R 1 are bound.

[0102] In a preferred embodiment, Ar comprises 3 bivalent aromatic or heteroaromatic ring systems based on the groups R-1 to R-166, where p is 0 and the dashed bond and an R 1 represent the bond to the aromatic or heteroaromatic group after R-1 to R-166. If the above-mentioned groups R-1 to R-166 represent several groups A 1 all combinations from the definition of A 1 Preferred embodiments are then those in which a group A 1 for C(R 1 )2, NR 1 , 0 or S and the other group A 1 for C(R 1 )2 or in which both groups A 1 represent S or 0 or in which both groups A 1 stand for 0 or S.

[0103] If A 1for NR 1 the substituent R 1 which is bonded to the nitrogen atom, preferably represents an aromatic or heteroaromatic ring system having 5 to 24 aromatic ring atoms, which can also be substituted by one or more radicals R 2 In a particularly preferred embodiment, this substituent R 1 identically or differently on each occurrence represents an aromatic or heteroaromatic ring system having 6 to 24 aromatic ring atoms, preferably having 6 to 12 aromatic ring atoms, which does not contain any condensed aryl groups or heteroaryl groups in which two or more aromatic or heteroaromatic 6-ring groups are directly condensed to one another, and which in each case also comprises one or more radicals R 2Particularly preferred are phenyl, biphenyl, terphenyl and quaterphenyl with linkage patterns as listed above for R-1 to R-35, where these structures are substituted by one or more radicals R 1 may be substituted, but are preferably unsubstituted.

[0104] If A 1 for C(R 1 )2, the substituents R 1 which are bonded to this carbon atom, preferably identically or differently on each occurrence, represent a linear alkyl group having 1 to 10 C atoms or a branched or cyclic alkyl group having 3 to 10 C atoms or an aromatic or heteroaromatic ring system having 5 to 24 aromatic ring atoms, which can also be substituted by one or more radicals R 2 R is particularly preferably 1 represents a methyl group or a phenyl group. The radicals R 1also form a ring system with each other, which leads to a spiro system.

[0105] In a further preferred embodiment of the invention, R 1 , identical or different at each occurrence, selected from the group consisting of H, D, F, CN, OR 2 , a straight-chain alkyl group having 1 to 10 C atoms or an alkenyl group having 2 to 10 C atoms or a branched or cyclic alkyl group having 3 to 10 C atoms, wherein the alkyl or alkenyl group is each substituted by one or more radicals R 2 may be substituted and wherein one or more non-adjacent CH2 groups may be replaced by O, or an aromatic or heteroaromatic ring system having 6 to 30 aromatic ring atoms, each substituted by one or more radicals R 2 may be substituted; two or more radicals R 1together form an aliphatic ring system. In a particularly preferred embodiment of the invention, R 1 identically or differently on each occurrence selected from the group consisting of H, a straight-chain alkyl group having 1 to 6 C atoms, in particular having 1, 2, 3 or 4 C atoms, or a branched or cyclic alkyl group having 3 to 6 C atoms, where the alkyl group is substituted with one or more radicals R 2 may be substituted, but is preferably unsubstituted, or an aromatic or heteroaromatic ring system having 6 to 24 aromatic ring atoms, each substituted by one or more radicals R 2 can be substituted, but is preferably unsubstituted.

[0106] In a further preferred embodiment of the invention, R 2identical or different on each occurrence H, F, an alkyl group having 1 to 4 C atoms or an aryl group having 6 to 10 C atoms, which may be substituted by an alkyl group having 1 to 4 C atoms, but is preferably unsubstituted.

[0107] In a further preferred embodiment of the invention, all radicals R 1 , insofar as they represent an aromatic or heteroaromatic ring system, or R 2 as long as they represent aromatic or heteroaromatic groups selected from the groups R-1 to R-166, which, however, are then each substituted with R 2 , or the one at R 2 mentioned groups are substituted.

[0108] In a preferred embodiment of the invention, all aromatic or heteroaromatic groups of the radicals R, R 1 or R 2 selected from the corresponding groups R-1 to R-166, preferably selected from the groups R-1 to R-166, where A 1 for C(R1 )2 or the corresponding residue C(R 2 )2 or C(R 3 )2, or 0 or S.

[0109] In a preferred embodiment, the radicals R do not form any further aromatic or heteroaromatic groups fused to the basic structure of formula (1).

[0110] The above-mentioned preferred embodiments can be combined with each other as desired within the limitations defined in claim 1. In a particularly preferred embodiment of the invention, the above-mentioned advantages occur simultaneously.

[0111] The compounds of formula (1) used in the process according to the invention can be prepared by synthesis steps known to the person skilled in the art, such as bromination, Suzuki coupling, Ullmann coupling, Heck reaction, Hartwig-Buchwald coupling, etc.

[0112] The 1-(2-aminoaryl)carbazoles (3) required for the preparation of indolocarbazoles (4) can be prepared, for example, from literature-known, 1-functionalized carbazoles (1) and 2-functionalized anilines (2) in a Suzuki coupling, whereby in each case a Cl, Br, I or OTf is reacted with a boronic acid or boronic acid ester function B(OR)2 (step 1 in Scheme 1). Instead of the 2-functionalized anilines (2), 2-functionalized nitroaromatics can also be used. The 1-(2-nitroaryl)carbazoles thus obtained can then be reduced to the 1-(2-aminoaryl)carbazoles (3) by methods common to the person skilled in the art, e.g., transition metal-catalyzed (homogeneous or heterogeneous) with hydrogen as the reducing agent or in an acidic medium with Sn or Zn. In addition, syntheses of 1-(2-aminoaryl)carbazoles (3) from 2,3'-biindolyls and ketones are known, see WE Noland et al., Tetrahedron, 2018, 74, 2391 ; P. Huang, et al., Org. & Biomol. Chem., 2017, 15(45), 9622.

[0113] The resulting 1-(2-aminoaryl)carbazoles are diazotized, preferably under anhydrous conditions in an inert solvent such as tetrahydrofuran, dioxane, dichloromethane (DCM), or acetonitrile (MeCN), under acid catalysis, preferably with tetrafluoroboric acid etherate and an alkyl nitrite as the diazotizing agent, preferably with t-butyl, amyl, or iso-amyl nitrite. After adding the diazotizing agent and briefly stirring, the mixture is slowly warmed to room temperature, forming the product (4) with evolution of nitrogen and cyclization. The exothermic reaction can be moderated by suitable temperature control; if necessary, the reaction is completed by gentle heating.

[0114] For the sake of clarity, the representation of substituents on (1), (2), (3), and (4) has been omitted below. The reactant (1) can be part of a larger condensed system, e.g., an indenocarbazole, indolocarbazole, benzofurocarbazole, benzothiophenocarbazole, etc., while the reactant (2) can be part of a naphthyl, anthracenyl, phenanthrenyl, triphenylenyl, fluorenyl, spirobifluorenyl, dibenzofuranyl, dibenzothiophenyl, carbazolyl, etc.

[0115] Scheme 1 :

[0116] 3 4 Similarly, with a group Y 2 bridged amines (5) are converted to (6), whereby the Y 2 bridged carbazoles (7) (Scheme 2). Scheme 3 shows the analogous reaction of with groups Y 1 and Y 2 bridged amines (8), yielding the doubly bridged compounds (9).

[0117] Scheme 2:

[0118] Y 1: Single bond, BR, CR2, SiR2, GeR2, NR, P(O)R, O, S, SO2, Se, Te

[0119] Y 2 : BR, CR2, SiR2, GeR2, NR, P(O)R, O, S, SO2, Se, Te. The invention is further illustrated by the following examples, without intending to limit it. Those skilled in the art can, from the descriptions, practice the invention within the entire disclosed scope and, without inventive step, apply the inventive process to other compounds that can be used in electronic devices.

[0120] Examples:

[0121] Unless otherwise stated, the following syntheses are carried out under a protective gas atmosphere in dried solvents. The metal complexes are also handled in the absence of light or under yellow light. The solvents and reagents can be obtained, for example, from Sigma-ALDRICH or ABCR. The respective information in square brackets or the numbers given for individual compounds refer to the CAS numbers of the known compounds. For compounds that can exhibit multiple enantiomeric, diastereomeric, or tautomeric forms, one form is shown as a representative example.

[0122] Literature-known Synthone LS:

[0123] A) Synthesis of synthons S:

[0124] Example B1:

[0125] Step 1 : Synthesis of LS1 Variant 1 : Suzuki coupling in the presence of water

[0126] Preparation according to M. Moustakim et al., Bioorganic & Medicinal Chemistry (2018), 26(11 ), 2965. Preparation: 24.6 g (100 mmol) 1-bromo-9-H-carbazole [16807-11-7], 15.1 g (110 mmol) 2-aminophenylboronic acid [5570-18-3], 31.8 g (300 mmol) sodium carbonate, 1.16 g (1 mmol) tetrakis-triphenylphosphinopalladium(O) [14221-01-3], 200 ml dioxane, 100 ml EtOH, 100 ml water, 90 °C, 16 h. Workup: Addition of 500 ml ethyl acetate (EE) and 500 ml water, org. Separate the phase, extract the aqueous phase twice with 200 ml of EA each. Wash the combined organic phases twice with 300 ml of water each, twice with 200 ml of saturated sodium chloride solution each, dry over magnesium sulfate, and remove the EA in vacuo. Purification: chromatography on silica gel, n-heptane: dichloromethane (DCM), Torrent column chromatography from A. Semrau. Yield: 21.7 g (83 mmol) 83%; Purity: approx. 99% pure. 1 H-NMR.

[0127] Variant 2: Suzuki coupling under anhydrous conditions. Preparation: 24.6 g (100 mmol) 1-bromo-9-H-carbazole [16807-11-7], 15.1 g (110 mmol) 2-aminophenylboronic acid [5570-18-3], 63.7 g (300 mmol) tripotassium phosphate, 817 mg (1 mmol) 1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II), complex with dichloromethane [95464-05-4], 400 ml dioxane, reflux, 16 h. Workup: While still warm (70 °C), filter through a Celite bed pre-slurried with dioxane, rinse, and concentrate the filtrate in vacuo. Add 500 ml of DCM and 500 ml of water, separate the organic phase, and extract the aqueous phase twice with 200 ml of DCM each. Wash the combined organic phases twice with 300 ml of water and twice with 200 ml of saturated sodium chloride solution each, dry over magnesium sulfate, and remove the DCM in vacuo. Purification: chromatography on silica gel, n-heptane: dichloromethane (DCM), Torrent column chromatography system from A. Semrau. Yield: 25.0 g (96 mmol) 96%; Purity: approx. 99% pure. 1 H-NMR.

[0128] Step 2: Diazotization and cyclization Variant 1: Diazotization with alkyl nitrites

[0129] A well-stirred solution of 25.8 g (100 mmol) of LS1 in 1500 ml of dichloromethane (DCM) cooled to 0 °C is treated dropwise with 27.2 ml (200 mmol) of HBF4X Et2O, ~ 54 % [67969-82-8] over a period of approximately 15 min and then stirred for 10 min. A mixture of 15.9 ml (120 mmol) of t-butyl nitrite [540-80-7] (90%) and 100 ml of DCM is then added dropwise to the viscous, well-stirred reaction mixture over a period of 1 h. The mixture is stirred at 0 °C for 1 h. The mixture is then slowly warmed to approx. 20 °C over a period of approx. 5 h. The reaction is then completed by stirring for a further 10 h at approx. 20-25 °C. Caution: Nitrogen evolution! The exothermic reaction can be moderated by controlling the temperature. Once the nitrogen evolution has ceased, 200 ml of saturated sodium bicarbonate solution is slowly added (Caution: Foaming!), the mixture is stirred for a further 30 min., and the organic phase is separated.

[0130] The phase is separated, dried over magnesium sulfate, filtered off the desiccant, and the filtrate is concentrated at approximately 40 °C, replacing the distilled DCM with the continuous addition of approximately 200 ml of ethanol. The precipitated product is filtered off, washed twice with 50 ml of ethanol each time, and dried in vacuo. Yield: 16.5 g (68 mmol), 68%; Purity: approximately 98% pure. 1 H-NMR. Further purification can be carried out by chromatography (silica gel, n-heptane / DCM 2:1 > 1:1, or alternatively mobile phase), by recrystallization or by hot extraction crystallization (common organic solvents, e.g., DCM / acetonitrile mixtures), and by fractional sublimation under vacuum or high vacuum.

[0131] Instead of t-butyl nitrite [540-80-7], iso-amyl nitrite [110-46-3] can be used as an alternative.

[0132] Variant 2: Diazotization with nitrosyl salts

[0133] Procedure analogous to variant 1, whereby the t-butyl nitrite is replaced with 12.3 g (105 mmol) of nitrosyl tetrafluoroborate [14635-75-7], which is added as a solid in portions over 5-10 minutes. Yield: 15.3 g (63 mmol), 63%; Purity: approximately 98% pure. 1 H-NMR. When using di-, tri-, tetra-, etc. amino (-NH2) or bromine (-Br) building blocks, the stoichiometry in steps 1 and 2 is adjusted accordingly.

[0134] Analogously, the following compounds can be prepared via the two steps of Suzuki coupling and cyclization, with yields typically of 40-90% for monocyclizations and 20-60% for dicyclizations.

Claims

Patent claims Process for the preparation of indolo[3,2,1-jk]carbazole and derivatives thereof comprising the following steps: where in formula (1a), (2a) and (3a) the bond of the two rings containing Y 1 and N and Ar 3 cis- or trans-position, a) providing a composition comprising a compound of formula (1) or (1a) and at least one nitrosyl cation source; b) converting the composition from a) to a diazonium salt; c) optionally isolating the diazonium salt according to formula (2) or (2a); d) converting to a compound according to formula (3) or (3a); and wherein the symbols used are: Ar 1 , Ar 2 , Ar 3 are, identically or differently at each occurrence, an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which is linked by one or more radicals R may be substituted, where two or more R may form an aromatic or heteroaromatic ring system; Y 1 , Y 2 are, identical or different at each occurrence, a single bond, Se or R is the same or different at each occurrence and is H, D, F, CI, Br, I, OAr', N(R 1 )2, N(Ar')2, SAr', B(OR 1 )2, CHO, C(=O)R 1 , CR 1 =C(R 1 )2, CN, C(=O)OR 1 , C(=O)NR 1 , Si(R 1 )3, NO2, P(=O)(R 1 )2, OSO2R 1 , OR 1 , S(=O)R 1 , S(=O)2R 1 , SR 1 , a straight-chain alkyl group having 1 to 20 C atoms or an alkenyl or alkynyl group having 2 to 20 C atoms or a branched or cyclic alkyl group having 3 to 20 C atoms, wherein the alkyl, alkenyl or alkynyl group is each substituted by one or more radicals R 1may be substituted, with one or more non-adjacent CH2 groups being replaced by -R 1 C=CR 1 -, - S-, SO or SO2, or an aromatic or heteroaromatic ring system with 5 to 60 aromatic ring atoms, preferably with 5 to 40 aromatic ring atoms, each substituted by one or more radicals R 1 may be substituted, where two or more R radicals preferably bound to the same cycle may form an aliphatic, heteroaliphatic, aromatic or heteroaromatic ring system which may be substituted with one or more R radicals 1 can be substituted; Ar' is at each occurrence, identically or differently, an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which is substituted by one or more radicals R 1 may be substituted, where two or more R 1can form an aromatic or heteroaromatic ring system with each other; R 1 is the same or different at each occurrence H, D, F, I, B(OR 2 )2, CHO, C(=O)R 2 , CR 2 =C(R 2 )2, CN, C(=O)OR 2 , Si(R 2 )3, NO2, P(=O)(R 2 )2, OSO2R 2 , SR 2 , OR 2 , N(R 2 )2, S(=O)R 2 , S(=O)2R 2 , a straight-chain alkyl group with 1 to 20 C atoms or an alkenyl or alkynyl group having 2 to 20 C atoms or a branched or cyclic alkyl group having 3 to 20 C atoms, wherein the alkyl, alkenyl or alkynyl group is each substituted with one or more radicals R 2 and wherein one or more CH2 groups in the above-mentioned groups are substituted by -R 2 C=CR 2 -, -C=C-, Si(R 2 )2, C=O, C=S, -C(=O)O-, NR 2 , CONR 2 , P(=O)(R 2), -O-, -S-, SO or SO2 and where one or more H atoms in the above-mentioned groups can be replaced by D, F, CI, Br, I, CN or NO2, or an aromatic or heteroaromatic ring system with 5 to 30 aromatic ring atoms, each of which is substituted by one or more radicals R 2 may be substituted, where two or more radicals R 1 can form an aliphatic, heteroaliphatic, aromatic or heteroaromatic ring system; R 2 is, identically or differently at each occurrence, H, D, F, CN or an aliphatic, aromatic or heteroaromatic organic radical having 1 to 20 C atoms, in which one or more H atoms may be replaced by D or F; two or more substituents R 2 be linked together and form a ring; Z" is an anion, preferably from the nitrosyl cation source.

2. The process according to claim 1, wherein the process comprises the compounds of formula (1-1), (2-1) and (3-1): Formula (1-1) Formula (2-1) Formula (3-1 ) where the symbols used have the meanings given in claim 1 and additionally: X is the same or different at each occurrence CR or N with the proviso that a maximum of two groups X per cycle represent N.

3. A process according to claim 1, wherein the compounds of the formulas (1-1 a) to (1-1 h) are each converted into the compounds of formulas (3-1 a) to (3-1 h), where the symbols used have the meanings given in claim 1 and additionally: X is the same or different at each occurrence CR or N with the proviso that a maximum of two groups X per cycle represent N; W is BR, CR2, NR or 0.

4. The method according to one or more of claims 1 to 3, wherein the nitosyl cation source is soluble in the composition.

5. The process according to one or more of claims 1 to 4, wherein the nitrosyl cation source is selected from at least one nitrosyl salt and / or the combination of a nitrite compound with an acid.

6. The method according to one or more of claims 1 to 5, wherein the composition comprises at least one organic solvent.

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