JPH03261793A - Quinoxaline-palladium complex and production thereof - Google Patents

Abstract

NEW MATERIAL:A compound expressed by formula I [R<1> to R<4> are H, halogen, (halo)alkyl, alkoxy(carbonyl) or trialkylsilylmethyl, provided that both R<1> and R<4> are not H and R<2> and R<3> may link to form naphthalene ring; R<5> to R<7> are alkyl; X is halogen; n is >=1]. EXAMPLE:A compound expressed by formula II. USE:An intermediate for medicines and electrical and electronic materials. A raw material for quinomycin-based medicines can be derived from the low- molecular weight compound and electrically conductive polymers can be derived from the high-molecular weight compound by reduction. PREPARATION:Diisocyanobenzenes expressed by formula III are reacted with a palladium complex expressed by formula IV in an inert solvent such as preferably diethyl ether at 30-120 deg.C.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention is directed to a compound of the formula (I) (wherein R', R2, R3, R' are a hydrogen atom, a halogen atom, an alkyl group, a haloalkyl group, an alkoxy group) , represents an alkoxycarbonyl group, or a trialkylsilylmethyl group.However, R' and R' are not both hydrogen atoms.Also, R2 and R3 may combine to form a naphthalene ring.R5+R'+R7 represents an alkyl group, and X represents a halogen atom.

n represents a numerical value of 1 or more. ) and a method for producing the same.

<Prior Art and Problems to be Solved by the Invention> Palladium-based complexes in which three molecules of cyclohexyl isocyanide are inserted into a methyl-palladium bond are known.

However, nothing is known about quinoxaline-palladium complexes in which 1,2-diisocyanobenzenes are inserted to form a quinoxaline skeleton.

Further, the present inventors have discovered that 1,2-diisocyanobenzenes are polymerized by organozinc compounds to produce quinoxaline polymers, or the complexes are unstable and cannot be isolated.

<Means for Solving the Problems> As a result of intensive studies on the reaction between 1,2-diisocyanobenzenes and transition metals, the present inventors discovered that methyl It has been found that a quinoxaline-palladium complex can be obtained in which two adjacent isocyano groups are successively inserted into a -palladium bond to form a heteroaromatic ring, a quinoxaline skeleton.

Furthermore, when diisocyanobenzenes are present in excess,
The polymerization reaction proceeds to give a polymer while forming a xaline skeleton, and the isolated quinoxaline-palladium complex is not only stable in the air, but also when diisocyanobenzenes are further reacted with it, the xaline skeleton is formed. While forming , a living polymerization reaction proceeds to give a polymer with a higher degree of polymerization, and when a hydride or an alkylating agent is applied to the palladium complex, the terminal palladium-containing group becomes a hydrogen or alkyl group, etc. They found that it can be easily converted and completed the present invention.

That is, the present invention provides compounds of the formula (I) (wherein R', R2, R3, R' represent a hydrogen atom, a halogen atom, an alkyl group, a haloalkyl group, an alkoxy group, an alkoxycarbonyl group, a trialkylsilylmethyl group) However, R' and R' are not both hydrogen atoms.Also, R2 and R3 may combine to form a naphthalene ring.R5, Ra.

R7 represents an alkyl group, and X represents a halogen atom.

n represents a numerical value of 1 or more. ) a quinoxaline-palladium complex represented by R' (wherein R', R", R', and R' represent the same meanings as above), and a diisocyanobenzene represented by formula (III) R5Pd (PPhR'R')2X (I
II) (wherein Hs, Ra, R7 represent an alkyl group or an aralkyl group, and X represents a halogen atom). Production method, and (3) formula (IV) (wherein R1, R2, R3
, R4, Ra, R6, R7 represent the same meanings as above. m represents a numerical value satisfying l≦m. ) and the above-mentioned diisocyanobenzenes (I
I) (wherein R',
R', R', R', Rs, Rs, R' represent the same meanings as above. m is a number that satisfies 1≦m, l is a positive number and represents a number that satisfies 1<m+1+).

A method for producing a quinoxaline-palladium complex represented by
and (4) a quinoxaline represented by the above formula (I).
Palladium complex and metal hydride compound or MR”
,,Y.

(M is a metal from group IA to IIIA of the periodic table, IIB, p is M
valence, q is a number satisfying 0≦q<p, R1 is an alkyl group, a haloalkyl group, a trialkylsilylmethyl group,
An aralkyl group, an aryl group, and Y represent a halogen atom or an alkoxy group. ) is reacted with the formula (V
I) It is useful as an intermediate for drugs and electrical and electronic materials; for example, by reducing it, low molecular weight products can be used as raw materials for quinomycin drugs and semiconductor materials, and high molecular weight products can be used as raw materials for conductive polymers. can.

The present invention will be explained in detail below.

The diisocyanobenzenes used as raw materials in the present invention have the formula (n) (R', R", R", R', R5 and n have the same meanings as above. R9 is hydrogen or the above R8 The present invention provides a method for producing quinoxalines represented by the following.

The quinoxaline-palladium complex of the present invention has the following properties: (However, R' and R' are not both hydrogen atoms. In addition, R'' and R3 may combine to form a naphthalene ring.), and preferably the above-mentioned group. Alkyl groups, alkoxy groups, haloalkyl groups, and alkoxycarbonyl groups have 1 to 6 carbon atoms, especially 1 to 6 carbon atoms.
2 is preferred, and specifically, the alkyl group in the methyl, ethyl, propyl, trifluoromethyl, difluoromethyl, monofluoromethyl, trifluoroethyl, trialkylsilylmethyl group is preferably a methyl or ethyl group. These diisocyanobenzenes are disclosed in, for example, JP-A-1-1
It can be produced by a known method such as the method described in Japanese Patent No. 43850.

In addition, as a palladium complex, general formula (III) R6P
d(PPhR'R')2X (I[[) (wherein R
5, R11 and R7 represent an alkyl group or an aralkyl group, and X represents a halogen atom. ), where R5 is an alkyl group having 1 to 5 carbon atoms such as methyl or ethyl group, R', R
' is preferably an alkyl group having 1 to 6 carbon atoms such as methyl, ethyl, propyl, or hexyl group.

As shown in the following formula, the reaction involves two adjacent isocyano groups of the ortho-diisocyanobenzene compound being successively inserted into the R'-Pd bond to form a heteroaromatic ring and a quinoxaline skeleton, and a polymerization reaction is carried out. progresses. The growing end is a palladium complex attached to the quinoxaline backbone and can be isolated.

Furthermore, when the above-mentioned quinoxaline-palladium complex and diisocyanobenzenes are reacted, as shown in the following formula, PhR'R'P A quinoxaline-palladium complex with a high degree of polymerization can be obtained.

These reaction behaviors indicate that the polymerization is a living polymerization.

The reaction temperature is not particularly limited, but is generally preferably room temperature to 150°C and below the boiling point of the solvent, more preferably 30 to 120°C.

The reaction solvent is usually 1,2-diisocyanobenzene compound, and any solvent that dissolves the above palladium complex and the palladium complex produced and does not react with them can be used without particular limitation, but diethyl ether, tetrahydrofuran, etc. Preferred are ethers such as , tetrahydropyran and ethylene glycol dimethyl ether, aromatic hydrocarbons such as toluene and xylene, and halogenated hydrocarbons such as chloroform, chlorobenzene and methylene chloride.

Furthermore, since the reaction between quinoxaline and palladium complex is a living polymerization reaction, the average degree of polymerization of quinoxaline in the resulting quinoxaline-palladium complex is approximately proportional to the molar ratio of 1,2-diisocyanobenzene compound/palladium complex. Therefore, the molar ratio of quinoxaline and palladium complex can be adjusted as appropriate depending on the desired degree of polymerization. For example, when obtaining a quinoxaline-palladium complex in which n has an average number of quinoxaline chains of 1 to 200, the molar ratio is selected in the range of 1 to 200.

However, depending on the type of substituent, as the degree of polymerization increases, it becomes insoluble in the solvent, so the product may precipitate, and the degree of polymerization may not increase that much. Since the silylmethyl group has a high solubility of the resulting polymer in organic solvents, it is possible to obtain a palladium complex having a quinoxaline with a higher degree of polymerization.

The quinoxaline-palladium complex of the present invention is stable even in air and is easily isolated. In addition, even if it is isolated, it has the ability to restart polymerization when dissolved in a solvent and in the presence of a 1,2-diisocyanobenzene compound, and in that case, quinoxaline with a higher degree of polymerization - A palladium complex is obtained.

Therefore, quinoxaline with a quinoxaline polymerization degree of l
When a palladium complex and a 1,2-diisocyanobenzene compound are reacted to obtain a quinoxaline-palladium complex with an average number of quinoxaline chains of m+1, 1.2 per mole of the quinoxaline-palladium complex with an average number of quinoxaline chains of m. - One mole of the diisocyanobenzene compound may be used.

Moreover, the quinoxaline-palladium complex of the present invention is a metal hydride compound or MR', X.

(M is a metal from group IA to I [IA, IIB of the periodic table, p is M
, q is a number satisfying 0≦q<p, R8 is an alkyl group, haloalkyl group, trialkylsilyl methyl group, and X is a halogen atom or an alkoxy group. ) by reacting with an organometallic compound represented by Pd(PPhR'R')! X can be converted to -R'' (hydrogen or R'' above).

Specific examples of R8 include alkyl groups having 1 to 20 carbon atoms such as methyl, ethyl, n-propyl, 1so-propyl, n-butyl, 5eC-butyl, t-butyl, pentyl, hexyl, and pentadecyl, and their like. Examples include halogen substituted products and trialkylsilylmethyl groups.

Hydride compounds include NaB)I4, LiAI
Examples of the organic metals include Grignard reagent [R"MgBr (R" is the same as above)], AI
Organic aluminums such as R", AIR", CI, BR
Organic boron compounds such as ",", organic lithium compounds such as "LiR", etc.
Examples include organic zincs such as znR''□.

For example, by reducing with NaBH4, the terminus can be changed to -Pd
(PPhR'R')! X to -H and to -R8 by reduction with a Grignard reagent (R"MgC1:R" is an alkyl group, trimethylsilylmethyl group, aralkyl group, haloalkyl group), e.g. (CHs)asic
-CH25i(CH3
)3.

〔Effect of the invention〕

The quinoxaline-palladium complex of the present invention is useful as an intermediate for pharmaceuticals and electrical and electronic materials. For example, by reducing it, a low molecular weight one can be used as a raw material for quinomycin drugs and a semiconductor material, and a high molecular weight one can be used as a conductive material. It can be derivatized into polymers.

〔Example〕

Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited in any way by these Examples. -Diisonanobenzene (2a) was heated to 60°C in tetrahydrofuran (hereinafter referred to as THF), and the reaction was completed in 2 to 3 hours.

When the obtained quinoxaline-palladium complex was isolated and elemental analysis was performed, it was found that C: 52.55%, H: 5.67
%, N: 4.24% (calculated value C of the structure of (3a) below:
52.62%, H: 5.63%, N: 4.23%).

Further, when H'NMR (200MHz, CDC1z) measurement was performed, δ: 2.68.2.57.2.41.
2.37 and 2.29 (S, 3Hx 5. PtrC
H3), 7.10-7.45 (m, P-Ph, 10
)1), 1.52(t, 6H,j p,: 3.6Hz
) and 1.48 (t, 6H, Jp-H: 3.6Hz
) a peak appeared.

From the above results, this quinoxaline-palladium complex (3
It was confirmed that a) is equivalent to the methylpalladium complex (1 mmol) represented by PhMetP Br .

Example 2 T containing 0.5 mmo I (3a) obtained in Example 1
The HF solution was cooled to 0 °C and CCHx )ssicHJg
cI (1,4M, diethyl ether solution) was added dropwise using a syringe.

After the dropwise addition, the reaction solution was heated to reflux THF and allowed to react for 30 minutes. A pH 7 buffer was added to quench the excess Grignard reagent and extracted with chloroform. The organic layer was dried over anhydrous sodium sulfate, and precipitated Pd powder was removed using a short column of silica gel. The solvent was removed and evaporated using an evaporator to obtain a solid.

This solid was subjected to H'NMR (200MHz, CDC1a)
Upon measurement, δ: 0.09(S, 9H, 5i(
CHs)s), 2.52 (S, 2H, Ar-CH5)
, 2.4NS, 6H, Ar-CH5), 2.67,
A peak appeared at 2.71.2°73 (S, 3H, Ar-CHa).

This compound (4a) is now transferred to Me-1. It was confirmed that it was H2Si(Me)s.

As a result, this palladium complex (3a) can be easily converted to (C
H3) Reacts with 3SicHzMgc1, and the terminal becomes C
It turns out that it can be converted to H2SCH2S1 (.

Example 3 Methyl para, 3.4 per radium complex (1 mmol)
．． The same procedure as in Example 1 was carried out except that twice the mole of 5.6-tetramethyl-1,2-diisocyanobenzene (2a) was used. After the reaction is completed, the obtained quinoxaline-palladium complex is separated by liquid chromatography, and 2 of them are separated.
The species was analyzed.

-Product 5-a-1+ H'NMR (200MHz, CDC11) δ: 1.
4-1.6 (m, 12H, P-CH3) 1.71.2
．． 11.2.45"2.26.2.39.2.41゜2.49", 2,65.2.72.2.81.3.1
8゜(s, 3HX 9.6Hx 2”, Ar-CH
5) 6.7~6.8.7.3~7.4 (m, IOH,
P-Ph) Elemental analysis measurement value H: 6°06. C+61.69. N:8.0
7 Calculated value H: 5.97. C.61.78. N:8.
16.Product 5-a-2: H'NMR (200MHz, CDCl5) δ:
1.2-1.3 (m, 6H, P-CH3) 1.43
~1.56 (m, 6H, P-CH3) 1.71. 2.
11. 2.45"2.26. 2..39. 2.4
1°2.49", 2.65. 2.72. 2.8
1. 3.18゜(s, 3Hx7,6Hx 1", Ar
-CI5) 6.7-6.8. 7.3-7.4 (m,
10)1. P-Ph) From the above results, it was found that the two types of products were (n=3.5 for product 5-a-1 and n=2 for product 5-a-2).

Example 4 3,4.5.6-tetramethyl-1,2-diisocyanobenze: / (2a) 24.5 mg (0,13 mmo
l), 20.2 mg of methyl palladium complex (la) (
0,042 mmol) was dissolved in THF4- dried with LiAl84 under a nitrogen atmosphere, and this solution was heated to
The HF was refluxed and reacted for 15 minutes. The reaction solution was heated to 0°C.
Cool to
gC1] (1,4M diethyl ether solution) 0.2d
(0.28 mmol) was added dropwise using a syringe. The reaction solution was then heated to reflux the THF and allowed to react for 300 minutes.

A pH 7 buffer solution was added to quench the excess Grignard reagent, extracted with chloroform, and the organic layer was dried over anhydrous sodium sulfate, and precipitated palladium powder was removed using a short column of silica gel. . The solid obtained by distilling off the solvent with an evaporator was separated and purified using preparative recycling GPC (solvent: chloroform), and as a result, four types of products were obtained.

The analysis results for each product are shown below.

H'NMR (CDCl2) measurement results/Product 6-a
-1 δ: 0.07 (s, 9H, Si(Mez)s).

2.71 (s, 2H, CHzSi) 2.44. 2.46. 2.48”, 2.73.
2.78. 2.79゜2゜82(s, 3Hx
7.6Hx 1”, Ar-CF(a)・Product 6
-a-2 δ: 0.14 (s, 9H, Si(Met)s).

3.06 (s, 2H, CHzSi) 2.12. 2.14. 2.20. 2.21. 2
．． 32. 2.33°2.52”, 2.68.2
．． 72. 2.81. 2.85, 3.02 (s, 3H
X 11,6HX 1”, Ar-CI5)・Product 6-
a-3 δ: 0,06 (s, 9)1. Si(Mez)3).

2.68 (s, 2H, CH25i) 1.98. 2.03. 2.18. 2.21. 2
．． 25. 2.27°2.34", 2.37", 2.4
1”, 2.71”, 2.74”.

2.75 (s, 3Hx7, 6Hx5.Ar-CI5)・
Product 6-a-4 δ: 0.15 (s, 9H, Si(Mez)3).

3.07 (s, 2H, CHzSi) 1.93", 2.09", 2.12', 2.16", 2
．． 21°2.22. 2.25. 2.26. 2,3
4. 2.36. 2.41°2.43. 2.74.
2.76, 2.80. 2.83. 3.05 (s
, 3Hx7, 6Hx5. Ar-CI5) As a result, these compounds are represented by the following formula (6a), and the yield is n = 2 (6-a-1) is 20X Xn ~ 3 (
6-a-2) was 49X, n~4(6-a-3) was 16X, n~5(6-a-4) was 2X, and the total yield was 87X. From this result, it was confirmed that a palladium complex of the following formula (7a) (n is 2.3.4 and 5) was produced.

Example 5 Reaction was carried out in the same manner as in Example 4 except that the reaction molar ratio of 3,4.5.6-dicyanobenzene (2a) and methylpalladium complex (la) was changed to the molar ratio shown in Table 1. Separated and purified.

The results are shown in Table 1.

Table 1

Claims (4)

[Claims] (1) A quinoxaline-palladium complex represented by formula (I). ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, R^1, R^2, R^3, R^4 are hydrogen atoms,
Represents a halogen atom, an alkyl group, a haloalkyl group, an alkoxy group, an alkoxycarbonyl group, and a trialkylsilylmethyl group. However, R^1 and R^4 are not both hydrogen atoms. Further, R^2 and R^3 may be combined to form a naphthalene ring. R^5, R^6, R^
7 represents an alkyl group, and X represents a halogen atom. n represents a numerical value on one side. ) (2) Formula (II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) (In the formula, R^1, R^2, R^3, R^4 are hydrogen atoms,
Represents a halogen atom, an alkyl group, a haloalkyl group, an alkoxy group, an alkoxycarbonyl group, and a trialkylsilylmethyl group. However, R^1 and R^4 are not both hydrogen atoms. Further, R^2 and R^3 may be combined to form a naphthalene ring. ) Diisocyanobenzenes represented by formula (III) R^5
Pd(PPhR^6R^7)_2X(III) (in the formula, R
^5, R^6 and R^7 represent an alkyl group, and X represents a halogen atom. ) The method for producing a quinoxaline-palladium complex (I) according to claim 1, characterized in that the quinoxaline-palladium complex (I) is reacted with a palladium complex represented by: (3) Formula (IV) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(IV) (In the formula, R^1, R^2, R^3, R^4 are hydrogen atoms,
Represents a halogen atom, an alkyl group, a haloalkyl group, an alkoxy group, an alkoxycarbonyl group, and a trialkylsilylmethyl group. However, R^1 and R^4 are not both hydrogen atoms. Further, R^2 and R^3 may be combined to form a naphthalene ring. R^5, R^6, R^
7 represents an alkyl group, and X represents a halogen atom. m represents a numerical value satisfying 1≦m. Formula (V) characterized in that the quinoxaline-palladium complex represented by ) is reacted with the diisocyanobenzene (II) according to claim 2 in an amount of 1 mole in terms of palladium. ▲ Numerical formula, chemical formula, table etc.▼(V) (In the formula, R^1, R^2, R^3, R^4, R^5, R
^6 and R^7 each represent the same meaning as above. m is 1
A number that satisfies ≦m, l is a positive number, and represents a number that satisfies 1<m+l. ) A method for producing a quinoxaline-palladium complex. (4) The following formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, R^1, R^2, R^3, R^4 are hydrogen atoms,
Represents a halogen atom, an alkyl group, a haloalkyl group, an alkoxy group, an alkoxycarbonyl group, and a trialkylsilylmethyl group. However, R^1 and R^4 are not both hydrogen atoms. Further, R^2 and R^3 may be combined to form a naphthalene ring. R^5, R^6, R^
7 represents an alkyl group, and X represents a halogen atom. n represents a number of 1 or more. ) A quinoxaline-palladium complex and a metal hydride compound or MR^8_p_-_qY_q (M is a metal of group IA to IIIA of the periodic table, IIB group, p is the valence of M,
q is a number satisfying 0≦q<p, R^8 is an alkyl group, haloalkyl group, trialkylsilylmethyl group, aralkyl group, or aryl group, and Y is a halogen or alkoxy group. ) Formula (VI) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (R^1, R^2, R^3, R^4, R^5 and n are the above (Means the same thing as R^8. R^9 means hydrogen or the same thing as R^8 above.) A method for producing a quinoxaline represented by: