"HELICAL DISPIRODIINDENOPYRIDINES AND

DISPIRODIINDENOPYRIDAZINES, AND PREPARATION AND USES

THEREOF"

DESCRIPTION

Technical Field of the Invention

The present invention concerns dispiroindenopyridines and/or dispiroindenopyridazines and derivatives thereof, methods for their preparation, the study and definition of their properties, and their uses. In particular, the present invention relates to the preparation of new classes of helical molecules represented by the following general formulae A) and/or A') and/or B) and/or B') for use in applications in the field of organic electronics, since they have proved to have greater and more advantageous properties in comparison with the other organic molecules that may be taken into consideration as candidates for the same use.

In said formulae, A), A') and B), B') represent, respectively, derivatives of heical dispiroindenopyridines and dispiroindenopyridazines , as will be described in detail in the following description .

Description of the Prior Art

Drawbacks and/or Problems

At present, inorganic electronics is essentially based on materials characterized by good electron mobility due to the presence of ionic or covalent bonds in their crystalline structure; however, it still has a number of drawbacks such as, for example, the need for complex equipment, high costs, and lack of mechanical flexibility .

Organic-based electronics is expected to shortly replace inorganic electronics because of its numerous potential advantages in terms of, for example, flexibility, low cost, easy material deposition, possibility of production in environmentally-friendly conditions, appropriate modulation of the electronic properties by chemical synthesis, and so forth. Nevertheless, the current research has not yet provided a competitive practical solution that could be used as an alternative to those currently known and implemented in the art.

Technical Problem

Therefore, the need is still felt in the art for novel organic compounds having the above-mentioned favourable characteristics, so as to fulfil a greater number of requirements than the other known molecules for applications in the electronics field in general, and particularly in the organic electronics field.

Summary of the invention

While tackling the above-described problem, the present inventor conducted an in-depth study on the correlation between the structure and the properties of organic molecules that may potentially be used in the field of organic electronics. As a result of said study, the inventor found that two novel classes of helical dispiroindenopyridines and/or, respectively, dispiroindenopyridazines, and their derivatives, could provide an adequate solution to the above-mentioned technical problem. It is therefore one object of the present invention to provide two classes of molecules (helical dispiroindenopyridines and/or dispiroindenopyridazines, and derivatives thereof) represented by the general formulae A) and/or A') and/or B) and/or B'), respectively, as set out in the following description and in the appended independent claim.

It is another object of the present invention to provide a method for the preparation of said molecules, as set out in the following description and in the appended independent claim.

It is a further object of the present invention to provide the use of said molecules in the field of organic electronics, as set out in the following description and in the appended independent claim. It is yet another object of the present invention to provide novel intermediates for the preparation of said molecules, as set out in the following description and in the corresponding claims appended hereto. Further aspects of the present invention are set out in the appended dependent claims.

Detailed Description of the Invention The present invention concerns two novel classes of molecules represented by, respectively, the following general formulae A) and/or A') and/or B) and/or B'): wherein A), A'), B), B') represent each, respectively, derivatives of helical dispiroindenopyridines [A) and A')] and dispiroindenopyridazines [B) and B')]; and wherein R and R' independently represent hydrogen, an optionally substituted C ₁ -C ₆ hydrocarbon group (wherein the substituents may be straight-chain or, preferably, branched-chain ones in order to further stiffen the molecular structure and promote fluorescence), an optionally substituted aromatic group (e.g. phenyl, benzyl, p-tolyl, 4-methoxyphenyl, 4-bromophenyl, (trifluoromethyl)benzyl, thiophen-3-yl, naphthalen-1- yl, o-tolyl), or a trimethylsilyl group;

The X's represent each, independently, an optionally substituted C ₁ -C ₆ hydrocarbon group (wherein the substituents may be straight-chain or, preferably, branched-chain ones in order to further stiffen the molecular structure and promote fluorescence), a trifluoromethyl group, a difluoromethyl group, a phenyl group, a benzyl group, or an alcoxyl group.

Preferred methods according to the present invention for the preparation of the compounds of general formulae A) and B) and, respectively, A') and B') are summarized below by way of example in the following summary diagrams Summary Diagram 1 and Summary Diagram 2,,which also fall within the scope of the invention.

Summary Diagram 1

2,6-dibromobenzaldehydeanditsderivativeswithX=-CH ₃ ,- CH ₂ -CH ₃ ,C ₆ H ₅ -,-OCH ₃ and-OCH ₂ CH ₃ inposition4or -OCHsand-CH ₃ inposition3arecommerciallyavailable

2-bromobenzaldehydeanditsderivativeswith X=H andR=C ₆ H ₅ -orX=-OCH ₃ and-CF ₃ inposition4andR=H arecommercially available

ThecompoundwithR’=H andX=H is

Sonogashiracoupling commerciallyavailable

Sonogashiracoupling

R’=H orR

(thecorrespondingalkyneis X=H ororganicresidue commerciallyavailable)

Nucleophilicadditionof2molesof cyanideion,hydrogencyanideor alkylsilylcyanidewithsubsequent

Alkynylation deprotection

Nucleophilicadditionof1moleofcyanide ion,hydrogencyanideoralkylsilylcyanide Cocyclotrimerization withsubsequentdeprotection

R”=H ororganicresidue

Cocyclotrimerization

1)Oxidation

2)2-LiC ₆ H ₄ -Ph

1)Oxidation

2)2-LiC ₆ H ₄ -Ph Summary Diagram 2

Commerciallyavailable

Sonogashiracoupling

Nucleophilicadditionof2molesof cyanideion,hydrogencyanideor alkylsilylcyanidewithsubsequent deprotection

Nucleophilicadditionof1moleofcyanide ion,hydrogencyanideoralkylsilylcyanide withsubsequentdeprotection

B') The key phase of said preparation methods of the present invention is the so-called " Cocyclotrimerization" reaction, which provides the intermediate compounds 6a, 6b (Summary Diagram 1), 11a, lib (Summary Diagram 2), respectively .

Said cocyclotrimerization reaction was found to be particularly preferable because of its peculiar advantageous properties, such as, for example, high atomic economy, mild reaction conditions, triple-bond selective catalysts, tolerance for different functional groups, regioselectivity in intramolecular reactions. Experimental procedures for effecting this cocyclotrimerization reaction apply a general method for the cyclotrimerization of the compounds 5a and 5b of Summary Diagram 1 and 10a and 10b of Summary Diagram 2_, respectively, in the presence of a metallic catalyst M based on complexes of Rh and/or Co and/or Ni and/or Ir.

By way of non-limiting example, said catalyst M may be selected among the group including known complexes of rhodium (e.g. Wilkinson's catalyst

(chlorotris(triphenyl-phosphine)rhodium(I), RhCl(PPh ₃ ) ₃ ) and the like), cobalt (CpCo(L ₂ ) and the like), nickel (Ni(cod) ₂ + 3PPh _s , and the like), iridium (IrCl(cod) ₂ and the like).

The following will illustrate, by way of non-limiting example, some of the most preferred embodiments of said cocyclotrimerization reaction according to the present invention .

Procedure 1) A dry microwave vial is loaded with the starting material, which is dissolved in a solvent like, for example, tetrahydrofuran (THE) under argon atmosphere. After the addition of a catalyst, e.g. the above-mentioned Wilkinson's catalyst, and of additional Ag ₂ CO ₃ , the reaction vessel is sealed and heated in a microwave reactor. The reaction mixture is then cooled to room temperature and the solvent is evaporated under reduced pressure to give the raw final product.

The modes of operation and the reagent quantities employed were inferred and gathered from publication: Angew. Chem. Int. Ed. 2019, 58, 17169-17174, which is therefore attached hereto by reference.

Procedure 2) A catalyst like, for example, cyclopentadienyl cobalt dicarbonyl, is added as a single portion to a solution of the starting compound in a solvent like, for example, p-xylene, in a carousel tube. The reaction vessel is heated in a carousel under argon atmosphere. If the reaction is slow, an additional quantity of catalyst is added during the reaction until the starting material is consumed. After cooling to room temperature, the mixture is diluted with dichloromethane (CH ₂ CI ₂ ), filtered through a thin layer of silica gel, and concentrated under a vacuum. The subsequent purification of the residue by flash chromatography on silica gel gives the desired cyclized product .

The modes of operation and the reagent quantities employed were inferred and gathered from: Chem. Eur. J. 2014, 20, 8477-8482, which is therefore incorporated herein by reference in its entirety.

Procedure 3) A catalyst like, for example, cyclopentadienyl cobalt dicarbonyl, is added as a single portion to a solution of the starting product in a solvent like, for example, THF, under argon atmosphere. The reaction mixture is pumped through a flow reactor under high pressure and at high temperature. The resulting mixture is then filtered and concentrated under a vacuum. The subsequent purification of the residue by flash chromatography on silica gel gives the desired cyclized product.

The modes of operation and the reagent quantities employed were inferred and gathered from: Chem. Eur. J. 2014, 20, 8477-8482, which is therefore incorporated herein by reference in its entirety.

Procedure 4) A round-bottom side-arm flask containing Col2(dppe) and Zn is emptied and purged with nitrogen gas. The starting product and a solvent like, for example, acetonitrile (CH3CN) are then added into the flask by means of syringes. The reaction is then stirred. When the reaction is complete, the mixture is diluted with CH ₂ CI ₂ and filtered through celite and silica gel, and then the filtrate is concentrated. The raw residue is then purified through a column of silica gel to give the pure final product.

The modes of operation and the reagent quantities employed were inferred and gathered from: Org. Lett., Vol.9, No.3, 2007, which is therefore incorporated herein by reference in its entirety.

Procedure 5) The starting product is dissolved in pyridine and acetic anhydride (AC ₂ O) along with several crystals of dimethylaminopyridine (DMAP). The reaction is stirred at room temperature. Finally, the reaction mixture is concentrated under a vacuum to give the raw final product, which is then purified by flash chromatography on silica gel.

The modes of operation and the reagent quantities employed were inferred and gathered from: Org. Lett., Vol.9, No.3, 2007, which is therefore incorporated herein by reference in its entirety.

Procedure 6) Cyclopentadienyl cobalt dicarbonyl is added as a single portion to a solution of the starting product in p-xylene in a carousel tube. The reaction vessel is heated in a carousel to 140°C under argon atmosphere. If the reaction is slow, more cyclopentadienyl cobalt dicarbonyl is added as 0.5 equivalent portions during the reaction until the starting material is completely consumed. When the reaction is complete, the mixture is cooled to room temperature, diluted with CH ₂ CI ₂ , filtered through a thin layer of silica gel and concentrated under a vacuum. The residue is purified by flash chromatography through silica gel to give the desired purified final product.

The modes of operation and the reagent quantities employed were inferred and gathered from: Chem. Eur. J. 2014, 20, 8477-8482, which is therefore incorporated herein by reference in its entirety.

The following Examples will also summarize and describe the particularly preferred synthetic steps shown in the above-illustrated Summary Diagrams 1 and 2, respectively .

Of course, those skilled in the art will encounter no difficulty, in light of the bibliographic references broadly reported herein and of their own experience in the field of organic chemical synthesis, in reproducing the same processes without having to resort to any undue additional experimentation. Example 1

Commercial 2,6-dibromobenzaldehyde is dissolved in anhydrous CH ₂ CI ₂ . Propanediol, triethylorthoformate and ZrCl ₄ are added at room temperature and kept under agitation overnight. NaOH is then added and stirring is continued for one hour. The organic phase is separated, and the aqueous phase is extracted with Et ₂ O. The united organic phases are washed with water and dried on MgSC ₄ , then the volatile components are removed under a vacuum to give the acetal as a yellowish solid. Subsequently, the acetal is dissolved in THE and then n-BuLi is added at -78°C for 25 minutes, followed by other 90 minutes of agitation at the same temperature. The reaction mixture is then treated with methyl iodide and stirred for 25 minutes at -78°C. The reaction mixture is then left to heat to room temperature for about 1.5 hours. The resulting solution is quenched with HCl and stirred at room temperature for 1.5 hours.

The complete deprotection of the aldehyde is verified by gas chromatography (GC) analysis.

The reaction mixture is subsequently extracted with Et ₂ O, the united organic layers are washed with a solution of 10% aqueous sodium thiosulfate and water, dried on MgSO ₄ , filtered and evaporated under a vacuum. The resulting yellowish solid is purified by distillation in a Kugelrohr apparatus to give the final product as white crystals. The modes of operation and the reagent quantities employed were inferred and gathered from: Krzeszewski, M; et al., Chemistry-A European Journal 2016, 22(46), 16478, which is therefore incorporated herein by reference in its entirety.

Example 2

2 ,6-Dibromobenzaldehyde, phenylboronic acid, K ₂ CO ₃ and Pd(OAc) ₂ are introduced into a Schlenk flask, and all is purged with argon before use.

A toluene/water mixture (1:1, v:v) is added into the flask, and the resulting mixture is stirred at 80°C for 16 hours. After cooling, the two phases are separated and the aqueous phase is extracted with ethyl acetate. The organic phases are combined and the solvent is evaporated. The raw product thus obtained is then purified by flash chromatography through silica gel.

The modes of operation and the reagent quantities employed were inferred and gathered from: Krzeszewski, M; et al., Chemistry-A European Journal 2016, 22(46), 16478, which is therefore incorporated herein by reference in its entirety.

Example 3

63% 2,6-Dibromobenzaldehyde, 2- (tributylstannyl)thiophene and [Pd(PPh ₃ ) ₄ ] are introduced into a Schlenk flask, and all is purged with argon before use.

Toluene is added into the flask, and the resulting mixture is stirred for additional 15 minutes. Then the two phases are separated and the aqueous phase is extracted with ethyl acetate. The organic phases are combined and dried, and then the solvent is evaporated. The raw product thus obtained is purified by flash chromatography through silica gel.

The modes of operation and the reagent quantities employed were inferred and gathered from: Krzeszewski, M; et al., Chemistry-A European Journal 2016, 22(46), 16478, which is therefore incorporated herein by reference in its entirety.

Example 4

Dibromobenzaldehyde, benzo [b]thien-3-yl-boronic acid, K ₂ CO ₃ , PPh ₃ and Pd(OAc) ₂ are introduced into a Schlenk flask, and all is purged with argon before use. A mixture of toluene/water (1:1, v:v) is added into the flask, and the resulting mixture is stirred for 16 hours at 80°C. After cooling, the two phases are separated and the aqueous phase is extracted with ethyl acetate. Then the organic phases are combined and dried, and the solvent is evaporated. The raw product thus obtained is purified by flash chromatography through silica gel.

The modes of operation and the reagent quantities employed were inferred and gathered from: Krzeszewski, M; et al., Chemistry-A European Journal 2016, 22(46), 16478, which is therefore incorporated herein by reference in its entirety.

Example 5

O

96%

2-Bromobenzaldehyde, PdCl ₂ and CuI are dissolved in a mixture of triethylamine and anhydrous THE, then the desired corresponding alkyne is added and the reaction is stirred by reflux for 3 hours. The reaction mixture is then cooled, filtered through a layer of celite/silica gel using Et ₂ O as a solvent. The organic fraction is concentrated under reduced pressure, and a chromatography of the residue through a column of silica gel gives the above purified final product 3. The modes of operation and the reagent quantities employed were inferred and gathered from: Kaiser, Reinhard P.; et al., Angew. Chem. Int. Ed. 2019, 58, 17169, which is therefore incorporated herein by reference in its entirety.

Example 6

A solution of 2-ethynylbenzaldehyde in THE is added by syringe to a mixture of 2-bromobenzaldehyde, Pd (PPh3)2C12, CuI and Et3N in anhydrous THE at room temperature under hydrogen atmosphere. The reaction mixture is heated to 80°C under agitation for 1.5 hours. The reaction mixture is filtered and the precipitate is washed with water. The filtrate is then concentrated under reduced pressure, and the residue thus obtained is purified by chromatography through a column of silica gel to give the above compound 3.

The modes of operation and the reagent quantities employed were inferred and gathered from: Sota, Yumi; et al., Chemistry-A European Journal 2015, 21(11), 4398, which is therefore incorporated herein by reference in its entirety.

Example 7

The starting compound, CuI and Et ₃ N are added to a mixture of dichlorobis (triphenylphosphine)palladium and aryl halide in THE. The resulting mixture is stirred at 50°C overnight, then the reaction mixture is diluted with a saturated aqueous solution of NH ₄ CI. The resulting mixture is extracted three times with ethyl acetate, then the organic extracts are combined, washed with brine and dried on Na2SO4. The mixture is filtered and evaporated under reduced pressure. Finally, the residue is purified by chromatography through silica gel to give the above final product 3.

The modes of operation and the reagent quantities employed were inferred and gathered from: Yoshida, Kazuhiro; et al., Chemistry-A European Journal 2011, 17(1), 344, which is therefore incorporated herein by reference in its entirety.

Example 8

Trimethylsilylacetylene, CuI and Et ₃ N are added to a mixture of dichlorobis (triphenylphosphine)palladium and aryl halide in THE. The resulting mixture is kept under agitation at 50°C overnight, then the reaction mixture is diluted with a saturated aqueous solution of NH ₄ CI. The resulting mixture is extracted three times with ethyl acetate, then the organic extracts are combined, washed with brine and dried on Na2SO4. The mixture is filtered and evaporated under reduced pressure. Finally, the residue is purified by chromatography through silica gel to give the product. K ₂ CO ₃ is added to acetylene protected with trimethylsilyl. The mixture is diluted with water and then extracted three times with CH ₂ CI ₂ . The organic layers are then united, washed with brine and dried on Na2SO4. The mixture is filtered and evaporated under reduced pressure, and the residue is purified by chromatography through a column of silica gel to give the product. The latter, CuI and Et ₃ N are added to a mixture of dichlorobis (triphenylphosphine)palladium and aryl halide in THF. The resulting mixture is kept under agitation at 50°C overnight, then the reaction mixture is diluted with a saturated aqueous solution of NH ₄ CI. The resulting mixture is extracted three times with ethyl acetate, then the organic extracts are combined, washed with brine and dried on Na2SO4. The mixture is filtered and evaporated under reduced pressure. Finally, the residue is purified by chromatography through silica gel to give the above final product 3.

The modes of operation and the reagent quantities employed were inferred and gathered from: Yoshida, Kazuhiro; et al., Chemistry-A European Journal 2011, 17(1), 344, which is therefore incorporated herein by reference in its entirety. Example 9

2-Bromobenzaldehyde, PdCl ₂ (PPh ₃ ) ₂ and CuI are dissolved in a mixture of triethylamine and anhydrous THE, then the corresponding alkyne is added and the reaction is stirred by reflux for 3 hours. Subsequently, the reaction mixture is cooled and filtered through a layer of celite/silica gel using Et ₂ O as a solvent. The organic fraction is concentrated under reduced pressure and then a chromatography through a column of silica gel of the residue gives the above final product 3.

The modes of operation and the reagent quantities employed were inferred and gathered from: Angew. Chem. Int. Ed. 2019, 58, 17169-17174, which is therefore incorporated herein by reference in its entirety.

Example 10

Cyanideion(2moles), hydrogencyanideor alkylsilylcyanide/deprotection

Theseintermediateproductsarenovel,sincetheydonotexistinth eliterature

This type of reaction is a reaction of addition of 2 moles of cyanide ion, hydrogen cyanide or alkylsilyl cyanide (with subsequent deprotection) to the aldehyde. The reaction is novel, but the reaction type is classical and generally feasible. To the inventor's knowledge, the intermediate product 5b (cyanohydrin or cyanohydrin silyl ether) is not known in the literature; therefore, it is a part of the present invention.

There are many scientific publications about the reaction of addition of cyanide ion, hydrogen cyanide or cyanohydrin silyl ether to the aldehyde. The following may be mentioned as non-limiting examples: a)

Bandgar, B.P., et al., Green Chemistry 2001, 3(5), 265; or b)

Yoneda, R., et al., Chem. Pharm. Bull. 1987, 35(9), 3850; or, as an alternative, the general procedure for the alkynylation reaction may be followed, which uses the same reagent (2,2'-ethyne-1,2-diyl)dibenzaldehyde and/or derivatives thereof), as described in Kaiser,

R.P., et al., Angew. Chem. Int Ed. 2019, 58, 17169,

but, instead of the alkyne, in the present invention 2 cyanide ions, hydrogen cyanide or cyanohydrin silyl ether are used to give the cyanohydrin of the 5b type of the invention.

The modes of operation and the reagent quantities employed for this reaction were inferred and gathered from the aforementioned Angew. Chem. Int. Ed. 2019, 58, 17169, which is therefore incorporated herein by reference in its entirety.

This reaction is then followed by the cocyclotrimerization reaction previously described herein, to give the pyridazinic compound 6b.

Example 11

To the inventor's knowledge, the starting compound (6b) and the oxidized product obtained therefrom are not known in the scientific literature; therefore, they are also a part of the present invention. Many scientific publications exist about the oxidation reaction, but the most interesting and preferable one for the purposes of the present invention is described in Angew. Chem. Int. Ed. 2019, 58, 17169, wherein:

PCC (Precipitated Calcium Carbonate) and celite are added to a solution of the diol in anhydrous CH ₂ CI ₂ under argon atmosphere, and the resulting mixture is stirred for 3 hours at 25°C. Subsequently, the reaction mixture is filtered through a layer of silica gel/celite, washed with CH ₂ CI ₂ and concentrated under reduced pressure. A chromatography through a column of silica gel gives the desired oxidized product.

The modes of operation and the reagent quantities employed for the oxidation reaction of the present example were inferred and gathered from the aforementioned Angew. Chem. Int. Ed. 2019, 58, 17169, which is therefore incorporated herein by reference in its entirety.

Example 12

A solution of 2-bromobiphenyl in anhydrous THE is cooled to -78°C and n-BuLi is added dropwise thereto. The resulting solution is stirred for 30 minutes, followed by the addition of the starting product in THF, and initially kept under agitation at -78°C, but subsequently allowed to reach room temperature. The reaction mixture is then poured in a saturated aqueous solution of NaHCO ₃ and extracted with Et ₂ O. The organic fractions are united, dried on MgSO ₄ filtered and concentrated under reduced pressure, and then the excess 2-bromobiphenyl is removed by chromatography through silica gel. The raw product is dissolved in CH ₃ COOH and HC1, and the resulting solution is stirred by reflux for 2 hours. The reaction mixture is subsequently diluted with water and neutralized with a saturated solution of K ₂ CO ₃ , then extracted with Et ₂ O. The organic fractions are united, dried on MgSO ₄ , filtered and concentrated under reduced pressure. A chromatography through a column of silica gel gives the desired final product B).

The modes of operation and the reagent quantities employed for this reaction were inferred and gathered from the aforementioned Angew. Chem. Int. Ed. 2019, 58, 17169, which is therefore incorporated herein by reference in its entirety.

Example 13 To the inventor's knowledge, the intermediate product 4 is not known in the scientific literature; therefore, it is also a part of the invention. n-BuLi is added dropwise to a solution of alkyne in anhydrous THE at -78°C. After stirring, the starting compound in THE is added and the reaction mixture is first stirred at -78°C and then allowed to heat to room temperature, still under agitation. Subsequently, an aqueous solution of NH ₄ CI is used in order to quench the reaction mixture, which is then extracted with Et ₂ O. The organic fractions are united, washed with a saturated solution of NaCl, separated and dried on Na2SO4, filtered and concentrated under reduced pressure. A chromatography through a column of silica gel of the obtained residue gives the desired product 4.

The modes of operation and the reagent quantities employed for this alkynylation reaction were inferred and gathered from the aforementioned Angew. Chem. Int. Ed. 2019, 58, 17169, which, among the numerous scientific publications on this topic, turned out to be the most suitable for the purposes of the present invention, and is therefore incorporated herein by reference in its entirety.

Example 14 To the inventor's knowledge, the starting compound 4 and the intermediate 5a are not known in the scientific literature; therefore, they are also a part of the invention.

As previously described, this type of reaction is a reaction of addition of a cyanide ion, hydrogen cyanide or alkylsilyl cyanide (with subsequent deprotection) to the aldehyde. Among the many scientific publications about the reaction of addition of cyanide ion, hydrogen cyanide or cyanohydrin silyl ether to the aldehyde, a particularly preferred one for the purposes of the present invention turned out to be Kaiser, Reinhard P.; et al., Angew. Chem. Int. Ed. 2019, 58, 17169. The modes of operation and the reagent quantities employed for this reaction were, in fact, inferred and gathered from the same publication, which is therefore incorporated herein by reference in its entirety.

This reaction is then followed by the above-described cocyclotrimerization reaction to give the pyridinic compound 6a.

Example 15

To the inventor's knowledge, the starting compound 6a and the corresponding oxidized intermediate thus obtained are not known in the scientific literature; therefore, they are also a part of the invention.

The two reactions of this example, wherein the pyridinic derivative A of Summary Diagram 1 is formed, are similar to those previously described for the preparation of the pyridazinic compound B of Summary Diagram 1 in Examples 11 and 12, and are executed in the same way. In this case as well, the modes of operation and the reagent quantities employed for these reactions were inferred and gathered from the aforementioned Angew. Chem. Int. Ed. 2019, 58, 17169, which is therefore incorporated herein by reference in its entirety.

Example 16

The phenyl derivative of 2-bromobenzaldehyde (the above-described compound 7 of Summary Diagram 2), PdCl ₂ (PPh ₃ ) ₂ and CuI are dissolved in a mixture of Et ₃ and anhydrous THE, then the corresponding alkyne is added and the reaction is stirred by reflux for 3 hours. The reaction is then cooled and filtered through a layer of celite/silica gel using Et ₂ O as a solvent. The organic fraction is then concentrated under reduced pressure and the residue is purified by chromatography through silica gel to give the product 8.

The modes of operation and the reagent quantities employed for this reaction were inferred and gathered from Angew. Chem. Int. Ed. 2019, 58, 17169, which is therefore incorporated herein by reference in its entirety.

Example 17

To the inventor's knowledge, the intermediate product 10b (cyanohydrin, but also cyanohydrin silyl ether) is not described in the scientific literature; therefore, it is a part of the invention.

This reaction is a reaction of nucleophilic addition of 2 moles of cyanide ions, hydrogen cyanide or alkyl silyl cyanide (with subsequent deprotection) which is similar to those previously described herein, and is therefore carried out, for example, in the same conditions and with substantially the same quantities as in the similar reaction previously described in Example 10.

This reaction is then followed by the above-described cocyclotrimerization reaction to give the pyridazinic compound lib.

EXAMPLE 18

To the inventor's knowledge, the starting compound lib and the corresponding oxidized intermediate thus obtained are not known in the scientific literature; therefore they are also a part of the invention.

The two reactions of this Example, wherein the pyridazinic derivative B') of Summary Diagram 2 is formed, are similar to those previously described for the preparation of the pyridazinic derivative B) of Summary Diagram 1 in Examples 11 and 12, and are executed in the same way. In this case as well, the modes of operation and the reagent quantities employed for these reactions were inferred and gathered from the aforementioned Angew. Chem. Int. Ed. 2019, 58, 17169, which is therefore incorporated herein by reference in its entirety.

Example 19

To the inventor's knowledge, the intermediate product 9 is not described in the scientific literature; therefore, it is a part of the invention. n-BuLi is added dropwise to a solution of alkyne in anhydrous THE at -78°C, and the reaction is first stirred at -78°C and then left to heat to room temperature, still under agitation. The reaction mixture is then quenched by adding an aqueous solution of NH ₄ CI and extracted with Et ₂ O, and the organic phases are united, washed with a saturated solution of NaCl, dried on anhydrous Na2SO4, filtered and concentrated under reduced pressure. The residue thus obtained is purified by chromatography through a column of silica gel to give the above intermediate product 9.

The modes of operation and the reagent quantities employed for this alkynylation reaction were inferred and gathered from the aforementioned Angew. Chem. Int. Ed. 2019, 58, 17169, which is therefore incorporated herein by reference in its entirety. Example 20

To the inventor's knowledge, the starting product 9 and the intermediate product 10a are not described in the scientific literature; therefore, they are also a part of the invention.

This reaction is a reaction of nucleophilic addition of a cyanide ion, hydrogen cyanide or alkylsilyl cyanide (with subsequent deprotection) to the aldehyde which is similar to the one previously described herein, and is therefore carried out, for example, in the same conditions and with substantially the same quantities as in the similar reaction described in Example 14.

This reaction is likewise followed by the above-described cocyclotrimerization reaction to give the pyridinic compound 11a.

Example 21 To the inventor's knowledge, the starting compound 11a and the oxidized intermediate product are not known in the scientific literature; therefore, they are also a part of the invention.

The two reactions of this Example, wherein the pyridinic derivative A') of Summary Diagram 2 is formed, are similar to those previously described for the preparation of the pyridinic derivative A) of Summary Diagram 1 in Example 15, and are executed in the same way. In this case as well, the modes of operation and the reagent quantities employed for these reactions were inferred and gathered from the aforementioned Angew. Chem. Int. Ed. 2019, 58, 17169, which is therefore incorporated herein by reference in its entirety.

Example 22

Suzuki reaction

The Suzuki reaction, previously mentioned in Summary Diagram 1, is a cross-coupling reaction where the coupling partners are a boronic acid and an organohalide catalyzed by a Pd(0) complex. It was first published in 1979 by Akira Suzuki (Miyaura, N.; Yamada, K.; Suzuki, A.; et al.; Tetrahedron Lett. 1979, 36, 3437).

In this type of reaction, a carbon-carbon single bond is formed by coupling an organoboron species with a halide using a palladium catalyst and a base.

The Suzuki coupling is effected via three key steps:

- Oxidative Addition,

- Transmetalation,

- Reductive Elimination.

Through this type of reaction it is possible to obtain the above-described compounds 2 of Summary Diagram 1.

Example 23

Sonogashira reaction

The Sonogashira reaction (Sonogashira, K.; Tohda, Y.;

Hagihara, N.; Tetrahedron Lett. 1975, 50, 4467), previously mentioned in Summary Diagram 1 and Summary Diagram 2, is a cross-coupling reaction where the coupling partners are a terminal alkyne and an aryl- or vinyl- halide. It uses a Pd(0) catalyst and a Cu (I) cocatalyst to form a carbon-carbon single bond.

The Sonogashiara coupling is effected via four key steps:

- Oxidative Addition,

- Transmetalation,

- trans/cis Isomerization,

- Reductive Elimination.

Through this type of reaction it is possible to obtain the above-described compounds 3 of Summary Diagram 1 and the above-described compound 8 of Summary Diagram 2. Advantages of the Invention

Advantageously, the novel heical molecules of dispirodiindenopyridines and dispirodiindenopyridazines of the present invention have proved to have greater and better characteristics for organic electronics applications, in comparison with the other known molecules that may be taken into consideration as candidates for the same use. Said characteristics can be attributed, in particular, to the presence of: 1) largely conjugated systems, 2) chiro-optical properties due to helicity, 3) spiro residues (which confer increased morphologic stability, while at the same time maintaining the electronic properties and having higher solubility than the corresponding compounds without spiro groups), 4) increased fluorescence due to the presence of the pyridazine residue and to the rigid structure of the spiro residue, and 5) functionalization due to the presence of nitrogen atoms (which may lead to formation of a so-called "push-pull" system, modulability through formation of pyridinium and pyridazinium salts, formation of N-oxides or N,N'-dioxides as anchoring groups for solar cells, and so forth).

It is also worth mentioning that dispirodiindenopyridazines seem to be the only existing class of molecules which possess two fluorophores groups (fluorene and pyridazine); thus, they permit a better modulation of optoelectronic properties such as, for example, multicolor fluorescence, and may originate new uses for making special materials such as, for example, smart luminescent materials.

Being spiro compounds, dispirodiindenopyridines and dispirodiindenopyridazines are characterized by steric factors that prevent solid-state packing; as a consequence, they have proved to be capable of reducing intermolecular interaction, thereby preserving the color purity and spectral stability of the fluorescence.

Moreover, due to the presence of spiro residues, they have an interesting potential for use as active materials for OLEDs, OTFTs, photodetectors, solar cells or lasers.

The chiro-optical properties of the helical dispirodiindenopyridines and dispirodiindenopyridazines are important in organic electronics, e.g. for the electronic circular dichroism or for use in chiral sensors. In fact, chirality is an additional property which is advantageous for organic electronics.

The protonation of the nitrogen atom may originate multicolor fluorescence because of the emission variation; this is essential for a smart luminescent material.

Furthermore, the presence of the nitrogen atom permits the functionalization and formation of a system characterized by the presence of a donor and an acceptor of electrons; all this is fundamental for the polarization of a "push-pull" system.

In addition, the formation of N-oxide turned out to be essential to confer the organic sensitizer property on the anchoring in a solar cell in order to increase absorption, i.e. to attain higher energy conversion efficiency.

The study of the present invention on the preparation of the novel classes of molecules, i.e. dispirodiindenopyridines and dispirodiindenopyridazines, and on their potential uses started from a preliminary study on candidate organic molecules for use in electronics: spiro compounds, helicenes and dispiroindenofluorenes.

Although efficient, such molecules have a limited number of properties useful for organic electronics in comparison with the dispirodiindenopyridines and dispirodiindenopyridazines of the present invention. Today, the technologies based on crystalline silicon are dominating the production of photovoltaic panels. Crystalline silicon offers many advantages, such as abundance, a radicated basic technology, the fact that it is a high-quality, high-stability material. Nevertheless, the most important drawbacks connected with silicon use are its indirect energy gap and the high costs incurred for fabricating silicon-based materials and devices.

In turn, the most interesting aspect of organic cells is the use of the potentials of the thin-film technology: the very small thicknesses, of the order of a few millionths of a millimeter, permit the realization of panels on flexible and light plastic substrates. In addition to lightness and flexibility characteristics, organic cells have the advantage that they can have different hues. The derivative compounds of dispirodiindenopyridines and dispirodiindenopyridazines of the present invention have thus proven to be particularly promising and useful for use in the organic electronics field. Industrial Applicability

The present invention has made it possible to realize novel derivative heical molecules of dispirodiindenopyridines and dispirodiindenopyridazines , and derivatives thereof, which have proven to be particularly useful in organic electronics applications, in comparison with both the inorganic compounds currently in use and the other organic molecules currently being taken into account as possible competitive candidates for such applications.

List of the most important commercially available compounds

2.6-dibromo-4-methylbenzaldehyde (Aldrich Partners Product-USA, AK Scientific Product Catalog, Manchester Organics Limited, AbaChemScene Product List, etc.)

2.6-dibromo-4-ethylbenzaldehyde (FCH Group Reagents for Synthesis, Aurora Building Blocks 5 and HE Chemical Product List)

3.5-dibromo- [1,1'-biphenyl]-4-carbaldehyde (Chemieliva Pharmaceutical Product List and Hong Kong Chemhere Co., Ltd)

2.6-dibromo-4-methoxybenzaldehyde (Aldrich Partners Product-USA, BIONET Screening and Fragments Library, BIONET Research Intermediates, FCH Group Reagents for Synthesis, etc.)

2.6-dibromo-4-ethoxybenzaldehyde (FCH Group Reagents for Synthesis, Aurora Building Blocks 8 and HE Chemical Product List)

2.6-dibromo-3-methoxybenzaldehyde (AOBChem USA

Product List, FCH Group Reagents for Synthesis, Aurora

Building Blocks 5, HE Chemical Product List, etc.) 2,6-dibromobenzaldehyde (Aldrich Partners Product- USA, TCI America Research Chemicals, TCI Europe Research Chemicals, TCI UK Research Chemicals, etc.)

2-bromobenzaldehyde (TCI America Research Chemicals, TCI Europe Research Chemicals, TCI UK Research Chemicals, BIONET Screening and Fragments Library)

3-dibromo-[1,1'-biphenyl]-2-carbaldehyde

(Chemieliva Pharmaceutical Product List)

2-bromo-4-methoxybenzaldehyde (Aldrich Partners Product-USA, Accela ChemBio Product List, BIONET Research Intermediates, Synthonix Product List, etc.)

2-bromo-4-trifluoromethylbenzaldehyde (Aldrich Partners Product-USA, BIONET Research Intermediates, Synthonix Product List, ALDRICH, etc.)

2-ethynylbenzaldehyde (BIONET Screening and Fragments Library, Accela ChemBio Product List, BIONET Research Intermediates, Synthonix Product List, etc.)

1-bromo-2-naphthaldehyde (TCI America Research Chemicals, TCI Europe Research Chemicals, TCI UK Research Chemicals, TCI Shanghai Research Chemicals, etc.)

2-bromo-6-methylbenzaldehyde (Aldrich Partners Product-USA, BIONET Research Intermediates, Synthonix Product List, ALDRICH, etc.)

2,2'-(ethyne-1,2-diyl)dibenzaldehyde (Aurora Building Blocks 7)

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