JPS5837324B2 - Method for producing 6-vinylindolo[2,3-b]quinoxaline polymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for preparing novel indolo[2,3-b)quinoxaline derivative polymers for use as photoconductors.

Conventionally, many organic substances have been known as organic photoconductors, including poIJ-N-vinylcarbazole.
These organic materials used as organic photoconductors have several advantages, such as being easy to form a film as a photoconductive layer, and the film is transparent and flexible. Generally, the sensitivity as a photoconductor is low, and methods have been proposed to increase the sensitivity by adding a sensitizer, but this low sensitivity has been a major obstacle to practical application. There is.

The present invention has been made with the object of eliminating the above-mentioned defects and providing an organic photoconductor having satisfactory photosensitivity as a photosensitive material for electrophotography.The present invention will be described below.

A haloethyl group is introduced into 6H-indolo(2,3-b)quinoxaline represented by the formula using a haloethylating agent in the presence of a base to form a 6-haloquinoxaline represented by the formula (wherein X is a halogen). By obtaining ethyl indolo[2,3-b]quinoxaline and dehydrohalogenating it, 6-vinylindolo(2,3-b)quinoxaline represented by the formula was obtained, and by radial polymerization of this, A polymer of 6-vinylindolo(2,3-b)quinoxaline is obtained.

6H-indolo (2.31b) represented by the above formula (I)
Quinoxaline is Ber. 28 2528 (1895
) or J-Org. Chem. 37589 (197
2) The 6-haloethyl indolo(2.3-b)quinoxaline represented by the above formula (II) can be prepared by combining the above 6H-indolo(2,3-b)quinoxaline with an appropriate solvent. It is obtained by dissolving the metal salt in sodium hydroxide, potassium hydroxide, sodium amide, thallium ethoxide, etc. to form a metal salt, and adding P-toluenesulfonic acid haloethyl ester, dihalogenated ethane, etc. to this and reacting it. .

In the above, sodium hydroxide, sodium amide, thallium ethoxide, etc. and P-toluenesulfonic acid haloethyl ester, dihalogenated ethane, etc. are used in equimolar amounts, and these are 6H-indolo(2.3-b)quinoxaline, etc. It is used in an amount of 1 to 5 moles per mole of.

Furthermore, when dihalogenated ethane is used in the above, it is desirable to use a combination of halides with different activities in order to suppress its side reactions.
Chloriodoethane is the most suitable.

Suitable examples of the above solvent include N,N-dimethylformamide, dioxane, acetone, tetrahydrofuran and acetonitrile.

6-vinylindolo[2,3-
b] Quinoxaline has the formula (
It is obtained by dehydrohalogenating the 6-haloethyl indo-(2.3-b) quinoxaline of n) using a base such as an alkali hydroxide or an alcoholate as a catalyst.

6-vinylindolo [2,3-b
] Quinoxaline easily undergoes radical polymerization to give a polymer represented by the following formula.

This polymer has photoconductivity and film-forming ability by itself, and is suitably used to form a photoconductive layer of an electrophotographic light-sensitive material.

The method for producing the above-mentioned 6-vinylindolo(2.3-b)quinoxaline polymer will be specifically explained below with reference to Examples.

Example 33.0 g of 6H-indolo(2.3-b)quinoxaline of formula (I) and 10.0 g of potassium hydroxide were dissolved in 500 g of N,N-dimethylformamide, and this solution was 35.2 g of p-toluenesulfonic acid mono-β-chloroethyl ester was added thereto for about 1 hour, and then kept at 65-75° C. for about 10 hours to react.

Next, a solution of 17.6 g of p-toluenesulfonic acid-β-chloroethyl ester and 5,0 g of potassium hydroxide dissolved in 100 TfLl of N,N-dimethylformamide was added, and the mixture was maintained at 65 to 75°C for 5 hours.

After cooling, the reaction solution was poured into a large amount of water, and the resulting yellow precipitate was filtered out, washed with water, and then dried.

This yellow precipitate was recrystallized from ethyl alcohol to obtain yellow needle crystals.

Yield: 30.3 g (yield: 72%). Melting point 1 3 8.5
In the ~139.5°co infrared absorption spectrum, the amine absorption observed in 6H-indolo(2.3-b)quinoxaline disappeared, and 2950 crrt
New methylene absorption was observed at 1' and 2900 cTL-'.

? C H N Cl calculated value (to) as elementary analysis C16H1N3Cl (X in formula (n) is CI)
68.20 4.29 14.93 12.58
Actual value (to) 68.07 4.14 14.85
12.81 The above results show that 6-(2-chloroethyl)indolo(2,3b]quinoxaline of formula was obtained.

6-(2-chloroethyl)indolo(2.3-b)quinoxaline thus obtained 14. '1 was dissolved in a mixture of 150 TL of tetrahydrofuran and 100 ml of ethyl alcohol, and a solution of 100 g of potassium hydroxide dissolved in 300 TL of methyl alcohol was added thereto, and the mixture was refluxed for 3 hours.

After cooling, the reaction solution was poured into about 14 g of ice water, and the yellow precipitate formed was filtered off, washed with water, and dried.

This precipitate was recrystallized from methyl alcohol to obtain yellow needle crystals.

Yield: 9.6 g (yield 78%). Melting point 142-143°C
(The above yellow crystals are 6-(2-chloroethyl)indolo(
2,3-b) When mixed with quinoxaline, the melting point decreased.

) In the infrared absorption spectrum, 2950C7TL-
' and 2900crrL-1 absorption disappears and new? 640 (X-1) and 960 cwL-1 showed terminal vinyl absorption.

As for elemental analysis C16H1N3 (Formula ■), C H N Calculated value 78.35 4.52 17.13 Actual value Hook 78.16 4.50 17.25 Based on the above results, 6-vinylindolo[2,3] of formula (III) -b
] It can be seen that quinoxaline was obtained.

6-vinyl indogate [2,3-b] thus obtained
11rrL of chlorobenzene obtained by rectifying 2.5g of quinoxaline and 3m9 of α,α′-azobisisobutyronitrile
1 and kept at 80° C. for 11 hours while blowing dry nitrogen gas.

After cooling, the reaction solution was poured into a large amount of ethyl alcohol.
The recovered yellow precipitate was filtered out, washed with methyl alcohol, and then dried.

After dissolving this in tetrahydrofuran, it was purified by pouring it into methyl alcohol for precipitation to obtain a yellow powder.

Yield: 2.0 g (yield: 80%).

When this powder is measured by infrared absorption spectrum,
1640Cr/L-1 and 960 due to the vinyl group found in 6-vinyl indo(2.3-b) quinoxaline
No absorption of crrL-' was observed, confirming that this powder was a polymer.

This polymer is easily dissolved in, for example, tetrahydrofuran, and a uniform film of the polymer can be prepared from the solution, and this film can be used as a photosensitive layer for electrophotography.

Claims (1)

[Claims] A haloethyl group is introduced into 6H-indolo(2,3-b)quinoxaline represented by formula 1 using a haloethylating agent in the presence of a base, and By obtaining 6-haloethylindolo(2,3-b)quinoxaline represented by 6, characterized by being polymerized;
- Process for producing a polymer of vinylindolo(2,3-b)+noxaline.