JPH02131466A - Method for producing pyridine analogues using methoxycarbonylcyclopentadienyl cobalt complex - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved production method for producing pyridine derivatives from alkynes and nitriles using a complex having the structure of methoxy-luponyl-pentadienyl cobaltborienes as a catalyst.

A method for producing substituted pyridines from alkynes and nitriles using cyclopentadienyl cobalt cyclic diene complexes and cyclopentadienyl cobalt cyclic diene complexes as catalysts is already known. For example, it is known that using a cycloalkagenyl cobalt cycloalkadiene complex and the same as a catalyst, two molecules of alkyne and one molecule of nitrile are bonded and cyclized at their triple bonds to obtain a substituted pyridine (Japanese Patent Application Laid-Open No. 50-13508
4, Japanese Unexamined Patent Publication No. 52-25780, US Pat. No. 4,267,329). However, it has been extremely difficult to synthesize a W jh cyclopentadienyl cobaltboriene complex compound in which an electron-withdrawing group is bonded to cyclopentadiene.

The present invention solves this difficulty by a novel preparation method, and η5
The present invention discloses that a -methoxycarbonylcyclopentadienylcobalt η4-polyene complex was obtained in good yield and that this complex is particularly effective as a catalyst for the production of pyridine and its homologs. The η5-methoxyluponylpentadienylcobaltboriene complex compound according to the present invention is prepared by the following route.

In the L formula (IV), X is halogen, and in the formula (I,
R1 is an unsubstituted polyene having 2 to 4 double bonds and having 4 to 12 carbon atoms, or a substituted polyene having 1 to 4 substituents (the substituent is an alkyl group having 1 to 4 carbon atoms, a phenyl group, or cyanomethylene group). However, R1 excludes boriene consisting only of aromatic rings. ] Or instead of formula (V), formula (Vl) or formula (V
■) According to

[In the formulas (■!) and (Vll), Rt2 is substituted or unsubstituted acetylene (the substituent is an alkyl group having 1 to 4 carbon atoms or a phenyl group, the number of substituents is 1 to 2),
R2 is a meclocyclic cyclopentadiene residue composed of an R'22 molecule and a cobalt atom, and corresponds to the substituent B12. The starting material of formula IV, methoxypentadienyl sodium, was prepared by the method according to Rausch'4 [J. Am. Ch
em. Soc, 102, 1196 (I980)
] can be obtained. Among the doristrifenylphosphine cobalt heptanohalogenides, for example, tristriphenylphosphine cobalt monochloride can be easily obtained by reacting cobalt chloride and triphenylphosphine in the presence of a reducing agent [Ino
rg. Chim. Acta, 3, 227 (i9
69)]. The reaction of formula (IV) is carried out by adding about the corresponding molar amount or a slight excess of methoxycarbonyl pentadienyl sodium in a solvent at a temperature of 0°C to 80°C from 0.1 to 24°C.
This can be done by reacting for a period of time. The reaction product obtained here can be purified by a fraction of a millimeter, or can be used as it is for the next reaction. (V, Vl. ■
) In the reaction of formula (IV), polyene or acetylene corresponding to the target substance is added to the reaction solution of formula (IV), and the temperature is heated from 0°C to 1°C.
This can be carried out by reacting at 50°C for 0.5 to 24 hours.

The Borien used here can be selected from a wide range, but
For example, butadiene, isobrene, substituted or unsubstituted cyclopentadiene, dicyclopentadiene, hexadiene, norpornadine, indene, cyclooctadiene,
These include cyclooctatetraene, azulene, cyclododecatriene, alkyl or phenyl substituted products thereof, and cyanomethylene substituted products. However, it does not include polyenes that only have aromatic rings, such as benzene, toluene, and xylene. Examples of acetylenes include acetylene, methylacetylene, ethylacetylene, phenylacetylene, diphenylacetylene, and the like. All reactions are preferably conducted in an inert atmosphere free of moisture, oxygen, carbon gas, etc. After the reaction product solution is concentrated, it can be separated and purified using column chromatography.

The obtained ηS-methoxycarbonylcyclopentadienyl cobaltboriene complex is relatively stable in air. The product obtained by formula (V) is a complex in which a methoxycarbonylcyclobentadienyl group is bonded to a cobalt atom in the form of nl1, and furthermore, the polyene defined by Rl forms a cobalt complex with the localized electrons of the diene moiety. It has a structure in which η4 bonds are formed with atoms. That is, this complex has the formula (I) [In formula (I), R is an unsubstituted polyene having 4 to 12 carbon atoms having 2 to 4 double bonds or a substituted polyene having 1 to 4 substituents. The cobalt atom is a cobalt atom that is bonded to the localized electron of the diene in the polyene (the substituent is an alkyl group having 1 to 4 carbon atoms, a phenyl group, or a cyanomethylene group). However, the borienes exclude borienes consisting only of aromatic rings. ].

In addition, in formula (Vl), instead of R, two molecules of acetylene or its derivative (R'2) react, and the product is a metallocyclic cyclopentadiene ring formed by the triple bond of the acetylene and cobalt. , and is a substance in which triphenylphosphine is coordinately bonded with cobalt. That is, the structure of this iron body is represented by the formula (II).
~4 alkyl groups or phenyl groups, number of substituents is 1
~4 pieces). ].

On the other hand, in formula (■), instead of the triphenylphosphine of the reaction product of formula (Vl), η6-methoxylponylcyclopentadienyl cobalt is bonded to form a cobalt-to-cobalt bond, and the cobalt-cyclopentadienyl ring is further bonded. It has a diene-coordinated structure. That is, the structure of this complex is the formula (II+) [In formula (01), R2 is the same as R2 in formula (II). ].

The η6-methoxyluponylcyclopentadienylcobalt η4-boriene complex shown in the present invention has extremely high activity when used as a catalyst in the reaction of alkynes and nitriles to produce substituted or unsubstituted pyridines. discovered.

Cycloalkyl dienyl cobalt complexes generally have catalytic activity in the synthesis of pyridine derivatives through the cocyclization reaction of alkyne and nitrile, but substituted cyclopentadienyl cobalt complexes in which cyclopenc diene is substituted with an electron-withdrawing group have even higher activity. It is.

Therefore, the η6-methoxyluponylpentadienylcobaltboriene complex disclosed in the present invention exhibits extremely excellent catalytic performance.

As for the reaction raw materials, even if the above catalyst is used, it can be applied to a wide range of alkynes and nitriles as in the prior art.

Examples of alkynes include acetylene. terminal alkynes, such as alkyl-, alkenyl- and aryl-acetylene;
Disubstituted acetylenes such as dialkyl-, diaryl-alkylalkenyl-acetylene and alkylaryl-acetylene, these alkynes may also be mixtures of different alkynes.

On the other hand, examples of nitriles include alkyl and aryl. Mononitrile such as alkenyl nitrile, and polyfunctional nitrile having a plurality of nitrile groups can be suitably used.

The molar ratio of alkyne to nitrile can be appropriately selected within the range of 0.01 to 100. However, in order to reduce by-products, it is better to have an excess of nitrile than alkyne.

In the method of the present invention, the reaction can proceed by adding a catalyst and optionally a solvent to an excess of nitrile in the presence or absence of a solvent, and adding the alkyne at a temperature of 50 to 200°C. can. As a solvent, it is not necessary to use saturated hydrocarbons, aromatic hydrocarbons,
Ethers, esters, alkylcarboxamides, etc. can be widely used. Moreover, it is of course possible to use the production compound obtained in the present invention immediately for the synthesis of pyridine and its homologues without separation and purification. This process is an advantageous choice for industrial use as a catalyst.

The method of the present invention is characterized by strong catalytic activity and high reaction rate.

Another major feature is that aromatic hydrocarbons produced as by-products along with the production of pyridine and its analogues can be significantly reduced. As a result, industrially satisfactory productivity and product concentration can be easily obtained.

In particular, when a lower alkyne such as acetylene is used as a raw material, the reaction can proceed at a sufficiently practical rate at a much lower pressure than in known systems. This fact is extremely important from a practical standpoint, considering that lower alkynes have an extremely high risk of decomposition and explosion due to pressurization.

With the present invention, for example, vinylpyridine, which is an industrially important product, can be produced for the first time. α-Vicolin. It can be said that it has become possible to industrially easily produce trisine and the like from acetylene and nitrile.

The embodiments of the present invention will be described below with reference to Examples, but the scope of the present invention is not limited by these embodiments. In addition,
Examples 1 to 6 show examples of catalyst synthesis, and Examples 7 to 15 show examples of pyridine production.

Example 1 Production of η4-norbornadiene-η5-methoxycarbonylpentadienyl cobalt.

Dimethyl carbonate (I.5mj!) is added to a tetrahydrofuran solution of cyclopentadienyl sodium (2m moil/nil solution is 7m!!) and heated under a nitrogen atmosphere for 1 hour. The resulting reaction solution was mixed with tristriphenylphosphine cobalt monochloride (
8.81g. 10m ma&') of benzene (2
0+ni') into the suspension. The mixture immediately becomes a red liquid, but after stirring occasionally to complete the reaction, norbornadiene (31j) is added, and the mixture is heated under reflux on a dry bath for 1 hour.

After cooling, pass through a short alumina column to remove insoluble matter, and collect the red-orange liquid eluted with benzene. The solvent was distilled off under reduced pressure and heating, and hexane (20 al) was added to the residue, which was left overnight. Precipitated triphenylphosphine (4.64g
) and remove the red liquid from the alumina chromatograph. Further triphenylphosphine (2.06 g) is recovered from the colorless liquid flowing out with hexane.

The solvent was distilled off under reduced pressure from the red-orange liquid flowing out with benzene/hexane (I:1), and the residue was dissolved by heating in hexane and left in the refrigerator to give orange crystals (2.0g; yield 73%).
) is obtained. Melting point 50-51t.

Analysis values C 61.27%, H 5.52%. CI41
Calculated value C B1.32% as 11502GO,
85.51%. IR (Nu Jol) 1720,
1700cl' (C=0). 'H-NMR (CD2
CI! 2) +δ0.77, 2.91, 3.14 (
Cylla); 3.81 (CH3); 4.8
8,4.91911In (C, +14) Production of η'-1,5-cyclooctadiene-η5-methoxycarbonyl pentadienyl cobalt.

In the same manner as in Example 1, bistriphenylphosphine-η5-methoxy cyclopentadienyl cobalt i9? After preparing 1,5-cyclooctadiene (2+aj) and leaving it at room temperature for 1 day. The treatment was carried out in the same manner as in Example 1 to obtain reddish brown crystals (0.45
8; yield 38%).

Melting point 8B-87℃. Analysis value C 62.13%, 86.5
9%. Calculated value C62 as C,sH,,02Co
．． 07%. H6.60%, IR (NuJol)
: 1720, 1700cm-'(C-0).
'H-NMR (CDCjs): δ1.63, 2.
3B, 3.58 (CaH+2); 3.95 (C
Hs) ; 4.40, 5.039911 (CsH
4) -1 fl η'-1,5-cyclooctatetraene-ηS-methoxycarbonyl pentadienyl cobalt. Example 1
Accordingly, a bistriphenylphosphine-η6-methoxycarbonylpentadienyl cobalt solution (5+
*moj) and cyclooctatetraene (Laj
) and then reflux for 1 hour under a nitrogen atmosphere. Distill the solvent off, dissolve in hexane, and chromatograph on alumina.
Triphenylphosphine (2.8 g) is recovered from the colorless liquid flowing out with benzene/hexane (I:1). Concentrate the reddish-brown liquid eluted with benzene/hexane (2:1), add hexane, and leave to stand to obtain reddish-brown crystals (0.46g).
．． yield of 32%). Melting point 67-68℃. Analysis value C B2.84%, H5.25% @ Cllllll
(Calculated value C as I2co 62.95%, H5.
28%, IR (NuJol): 1720, 17
00(C=0); 1B30cm-"(C=C).'
H-NMR (CIhCjz): δ3.64, 5.5
8 (CaHa); 3.90 (Clls); 4.
55, s. Production of tlppm(CsH4) -Ll η4-butadiene-ηS-methoxycarbonylpentadienyl cobalt. The bistriphenylphosphine-η6-methoxycarbonyl-pentadienyl cobalt solution (2.5+*s+oj') prepared according to Example 1 was added to 100+aj
Pour into a flask, replace the upper space with butadiene, cap tightly, and mix. After standing overnight at room temperature, the solvent was distilled off and the mixture was applied to alumina chromatography. Triphenylphosphine (I.5 g) is recovered from the colorless liquid flowing out with hexane. The red liquid obtained by elution with benzene/hexane (I:1) is dried under reduced pressure and left to stand to crystallize the residual dark red oil (0.25 g. Yield 42%).

Melting point 40-42°C (in a nitrogen-filled cavity). IR
(NuJol): 1710cm-' (C-0
), 'H-NMR (CDaCj2): δ-0.28,
1.84, 5.11 (C4Ha); 3.74 (
CHs); 4.9B, 5.291) I) II (CsH4
) -Production of triphenylphosphine-η6-methoxycarbonylpentadienyl (tetraphenylcobaltapentadiene). Bistriphenylphosphine-η5- according to Example 1
A methoxycarbonyl pentadienyl cobalt solution (5o+a+oj) was prepared and diphenylacetylene (I
．． Add 78g (low moj) and leave for 1 day. After concentration, alumina chromatography was performed, and the flowing reddish brown solution was concentrated with benzene/hexane (2:1), and hexane was added to give dark brown crystals (I.6 g; yield: 40
%). Melting point 153-155℃. Analysis value C 79.
84%, HS. 42%. Calculated value C as CS3H4202PCO 79.49%, 85.29%. IR
(Nujol): 1720cm"" (C-0
). 'l{-NMR (CDCjs): δ3.82
(C}Is); 4.69, 5.43 (CsH4);
6.4-7.41) 9m (C6HS).

衷ILdan [η5-methoxycarbonyl pentadienyl (cobalt pentadiene)] Production of η1-methoxycarbonyl pentadienyl cobalt (Co-Co).

According to Example 1, bistriphenylphosphine-η5
- A methoxycarbonyl cobalt solution (4+++ moj) is prepared and placed in a 200 mj flask, and the upper space is replaced with acetylene. Seal tightly and shake for 10 minutes. After concentration, it is applied to alumina chromatography. After thoroughly washing the column with benzene/hexane (I:1), the dark brown liquid eluted with benzene was concentrated, hexane was added, and the mixture was allowed to stand to give black crystals (0.24 g).

Furthermore, the green liquid that flows out is dried with benzene, xyhexane is added, and it is left in the refrigerator to produce green crystals (0.05 g; yield 3%).
). Melting point: 68-70°C (in a capillary filled with nitrogen) Analysis: C 51.94%, H 4.34%.

Calculated value C as C+aHtaO4CO2 51.9
5%, H4.36%. IR (Nujol): 1
710,1695ca+-'(C-0).

'H-NMR (CDCjs): δ3.85.3
．． 90(C}13); 4.92,5.10,5
．． 52.5.58 (I; sH4); 4.99, 8.2
5ppll (C<L). CIL η'-1. prepared by the method of Example 2 in a 100a+jl stainless steel autoclave under an argon atmosphere. 5
-cyclooctadiene-η5-methoxycarbonylcyclopentadienyl cobalt (catalyst I) 78 mg (0
．． 26m mojl) was dissolved in toluene 601, and then 20g of acrylonitrile was added. The autoclave was replaced with acetylene, and the temperature was reduced to 150 ml from normal pressure.
After heating to ℃, acetylene is constantly 13kg/cm2G.
I supplied it so that it would be. 2-vinylpyridine was synthesized by reacting for 60 minutes, and the reaction solution was analyzed by gas chromatography.

In addition, the acetylene supply pressure was changed from 13 kg/cc2G to 5
The reaction was carried out in exactly the same manner as above, except that the concentration was changed to kg/cm2G. The results of these reactions are shown in Table 1.

A: Triphenylphosphine-η5-methoxyluponylpentadienyl (tetraphenylcobaltacyclopentadiene) (catalyst II) prepared by the method of Example 5 as a catalyst 53 mg (0.07o+llo1).
5.0 g of acrylonitrile and the amount of 1.luene are aoa
The reaction was carried out in exactly the same manner as in Example 7 except that +i' was changed. The reaction pressure was 13 kg/cm2G. The reaction results are shown in Table 1. 63 II lg (0.23 l
lmojJ), 17.8g of acrylonitrile and 54aij of toluene! The reaction was carried out in the same manner as in Example 7 except that the reaction was changed to . The reaction pressure was 13 kg/cw2G. The reaction results are shown in Table 1.

Example 10 [η5-Methoxycarbonyl pentadienyl (cobalt pentadiene)] [η5-methoxycarbonyl pentadienyl cobalt ((:o-Go)] prepared by the method of Example 6 as a catalyst (catalyst rv)
Example 7 using 33B (0.08 m moi!), 6 g of acrylonitrile and 18 wj+ of toluene.
reacted in the same way. The reaction results are shown in Table 1.

The same operation as in Example 7 was repeated using a known catalyst. As a catalyst, bisic pentadienyl cobalt (catalyst V
), η'-1,5-cyclooctadiene-η5-cyclopentadiene cobalt (catalyst ■1) and η'-1-e
xo-cyanomethylcyclopentadiene-η5-cyclopentadienyl cobalt (catalyst ■) was added in an amount of 0.26 m moj equivalent to the catalyst (I).

Acrylic nitrile 5.0g, toluene 80+ as m agent
I prepared nj. Acetylene is supplied and the reaction pressure is 13 kg.
/cm2G. The results of these reactions are shown in Table 2.

(Left below) The complexes prepared by the methods of Examples 1 to 6 have high catalytic efficiency;
It is clear that the by-product of benzene is also small. Example 11 η'-1,5-cyclooctadiene-η5- as a catalyst
Methoxycarbonyl pentadienyl cobalt (catalyst 1) 26mg (0.09m wo1). Phenylacetylene log, acetonitrile 20g, and toluene 50+aj were charged and reacted at a temperature of 130°C for 120 minutes. Analysis of the product by liquid chromatography revealed that the amount of 2-methyldiphenylpyridine produced was 2.24 g, and the catalyst efficiency was loOmoj/Cog atoms. Acetylene and benzonitrile were reacted in 11 dishes using 76 mg of the same catalyst as in Example 1. The amount of preparation is benzonitrile 2
0g, toluene 6G+sj, reaction temperature 130℃
The reaction pressure was 10 kg/cm2G for 60 minutes. As a result of analyzing the product by gas chromatography, it was found that 20.2
g of 2-phenylpyridine was obtained, and the catalyst efficiency was 458
It was a+ofl/Co g atom. power i 4911
Using hydrogen cyanide instead of penzonitrile, 15-1
The same procedure as in Example 12 was carried out except that the reaction was carried out at 8 kg/cm2G. As a result, pyridine was obtained and the catalyst efficiency was 4.
It was 6 oj/Cog atoms. When the same reaction was carried out using catalysts (V) to (■) of Comparative Examples 1 to 3 instead of catalyst (I), only traces of pyridine formation were observed. In a 100A+J pressure-resistant glass reactor under an argon stream, 3hg of n4-cyclooctatetraene-n%-methoxycarbonylpentadienyl cobalt (0
．． 107m mof). After charging 2.5 g of acetonitrile and 60 mj of toluene, ethyl acetylene was blown in little by little while the reactor was deeply cooled to condense about 10 mj of liquid ethyl acetylene. Seal the reactor 12
Heated at 0°C for 4 hours.

After cooling, the reaction solution was analyzed using a gas chromatograph.
0.72 g of 2-methyldiethylpyridine was obtained, and the catalyst efficiency was 44 mo17 COg atoms.

25 mg (0.10
The reaction was carried out in exactly the same manner as in Example 14, except that 4m a+oj) was used.

Claims (1)

[Claims] 1) In the reaction of producing unsubstituted or substituted pyridine from algines and nitriles through a cyclization reaction, formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼…………( I) [In formula (I), R_1 is an unsubstituted polyene having 2 to 4 double bonds and 4 to 12 carbon atoms or a substituted polyene having 1 to 4 substituents, and the cobalt atom is It has a η^4 bond with the localized electron of the diene moiety in the polyene (the substituent is an alkyl group having 1 to 4 carbon atoms, a phenyl group, or a cyanomethylene group). However, this polyene excludes polyenes consisting only of aromatic rings. ] Or formula (II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼…………(II) [In formula (II), R_2 is a substituted or unsubstituted metallocyclic cyclopentadiene residue (the substituent has 1 carbon number) ~4
alkyl group or phenyl group, the number of substituents is 1 to 4
). ] Or formula (III) ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(III) [In formula (III), R_2 is the same as R_2 in formula (II). ] A manufacturing method characterized in that a η^5-methoxycarbonylcyclopentadienyl cobalt polyene complex shown in the following is present as a catalyst.