JPH07333872A - Electrophotographic photoreceptor - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic photoreceptor having satisfactory intense exposure characteristics, high sensitivity, low residual potential and high durability. CONSTITUTION:This electrophotographic photoreceptor has a photosensitive layer contg. an arylaminehydrazone compd. represented by formula I, wherein A is a group represented by formula II and III, etc., Q is a group represented by formula IV, n is an integer of >=1 when A is the group represented by the formula II or III, X is alkylene Ar is aryl or a heterocyclic group, each of B, D and E is a benzene ring, each of R<1>-R<3> is H, alkyl, etc., R<4> is alkyl, aryl, etc., and each of R<10> and R<11> is aryl, a heterocyclic group, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photoreceptor. More specifically, it relates to a high-sensitivity electrophotographic photoreceptor having a photosensitive layer containing an organic photoconductive substance.

[0002]

2. Description of the Related Art Conventionally, inorganic photoconductive substances such as selenium, cadmium sulfide and zinc oxide have been widely used in the photosensitive layer of electrophotographic photoreceptors. However, selenium and cadmium sulfide need to be recovered as poisons, selenium has poor heat resistance because it is crystallized by heat, cadmium sulfide and zinc oxide have poor moisture resistance, and zinc oxide has no printing durability. However, the efforts for developing a new photoconductor have been continued. Recently, studies have been conducted on the use of organic photoconductive materials in the photosensitive layer of electrophotographic photoconductors, and some of them have been put to practical use. Compared with inorganic photoconductive materials, organic photoconductive materials have advantages such as light weight, easy film formation, easy photoconductor production, and transparent photoconductor production depending on the type. Have.

Recently, a so-called function-separated type photoconductor, in which separate functions of charge carrier generation and transfer are shared by different compounds, has become the mainstream of development because it is effective for high sensitivity. The organic photoconductor is also put into practical use. Charge carrier transfer medium (hereinafter "CT
Abbreviated as "M". Examples of () include a case where a high molecular weight photoconductive compound such as polyvinylcarbazole is used and a case where a low molecular weight photoconductive compound is dispersed and dissolved in a binder polymer.

[0004]

In particular, organic low-molecular-weight photoconductive compounds can easily select mechanical properties as a binder because they have excellent film-forming properties, flexibility and adhesive properties. (See Japanese Patent Application Laid-Open No. 63-172161, Japanese Patent Application Laid-Open No. 63-174053, Japanese Patent Application Laid-Open No. 4-26726).
No. 1 and Japanese Patent Publication No. 5-15259).

Here, the performances required for an electrophotographic photoreceptor are (1) high chargeability due to corona discharge in a dark place, and (2) small attenuation of surface potential due to corona charge in a dark place. (3) Large attenuation of surface potential due to light irradiation, (4) Small residual potential after light irradiation, (5) Fluctuation of surface potential after repeated use, decrease in sensitivity, accumulation of residual potential. And (6) decrease in surface potential and sensitivity when exposed to strong light, little increase in residual potential, and quick recovery thereof.

Particularly when the residual potential is large, the electric charge remains in the exposed area, and when toner development is performed, the toner is also developed in the non-image area, resulting in a so-called fog image. Further, in reversal development, which is often used in printers and the like, the image density or contrast is lowered, and in an extreme case, a defect in which toner does not adhere to the image area occurs, resulting in a so-called white image. Both of these markedly reduce the reproducibility of the image and cannot be put to practical use.

Further, when the photoconductor is exposed to strong light, the surface potential and sensitivity are lowered, and the reproducibility of the image is remarkably lowered when the residual potential is greatly increased. It is desirable that the rise in potential be small and that they be recovered quickly. The behavior when the photoreceptor is exposed to strong light is called the strong exposure characteristic.In particular, the degree of decrease in surface potential is indicated by the strong exposure storage rate, and the degree of recovery of decrease in surface potential is indicated by the strong exposure return rate. The larger the value, the more preferable.

With the recent widespread use of reversal development type laser printers and the like, CTMs having high sensitivity, low residual potential and excellent durability suitable for combination with a charge generating material for long wavelength light such as phthalocyanine pigments. Development is strongly desired. In addition, laser printers are likely to be exposed to strong light during maintenance.
Good strong exposure characteristics are required for CTM.

[0009]

DISCLOSURE OF THE INVENTION The inventors of the present invention have keenly studied an organic low-molecular photoconductive compound which provides an electrophotographic photoreceptor having excellent strong exposure characteristics, high sensitivity, low residual potential and high durability. As a result of research, they found out that a specific arylamine hydrazone compound is suitable, and arrived at the present invention. That is, the gist of the present invention resides in an electrophotographic photoreceptor characterized by having a photosensitive layer containing an arylamine hydrazone compound represented by the following general formula [I] on a conductive support.

[0010]

[Chemical 2]

N is an integer of 1 or more when A is a group represented by the general formula [II] or [III], and 0 or 1 or more when A is a group represented by the general formula [IV]. Is an integer; X represents an alkylene group which may have a substituent;
Ar represents an aryl group which may have a substituent or a heterocyclic group which may have a substituent; B, D and E each represent a benzene ring which may have a substituent; May be the same or different from each other; R ¹ , R ² , R
³ , R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ are each a hydrogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent or a substituent which may have a substituent. Is a heterocyclic group, and when n is 2 or more, R ¹ in each structural unit may be different and R ² is the same; R ⁴ is an alkyl group which may have a substituent. Represents an aryl group which may have a substituent, a heterocyclic group which may have a substituent or an aralkyl group which may have a substituent;
R ¹⁰ and R ¹¹ are each an aryl group which may have a substituent, a heterocyclic group which may have a substituent, an alkyl which may have a substituent, and a substituent which may have a substituent. It represents an aralkyl group or an allyl group, and R ¹⁰ and R ¹¹ may be linked directly or via a bonding group. )

The present invention will be described in detail below. The electrophotographic photoreceptor of the present invention contains the arylamine hydrazone compound represented by the general formula [I] in the photosensitive layer.
In the above general formula [I], A is a general formula [II]

[0013]

[Chemical 3]

Represents a group represented by the following general formula [II]
Alternatively, the group represented by [IV] is preferable, and the group represented by the general formula [IV] is more preferable. Q represents a group represented by the following general formula [V].

[0015]

[Chemical 4]

When n is a group represented by the general formula [II] or [III], n is an integer of 1 or more, preferably any integer of 1 to 3, and 1 is preferable. A is a general formula [I
V] is a group represented by V], n is 0 or an integer of 1 or more,
Preferably, it is an integer of 0 to 3, 0 or 1
Is preferred. X represents an alkylene group such as a methylene group, an ethylene group or a propylene group, and a methylene group is particularly preferable. These alkylene groups may have a substituent, and examples of the substituent include a lower alkyl group such as a methyl group and an ethyl group; a lower alkoxy group such as a methoxy group and an ethoxy group; a halogen atom such as a chlorine atom and a bromine atom. An aryl group such as a phenyl group and a naphthyl group.

Ar is an aryl group such as a phenyl group, a naphthyl group or an anthracenyl group; a pyrrolyl group, a thienyl group,
It represents a heterocyclic group such as a furyl group or a carbazolyl group, and a phenyl group is particularly preferable. These aryl group and heterocyclic group may have a substituent, and examples of the substituent include a halogen atom such as a chlorine atom, a bromine atom and an iodine atom; a methyl group, an ethyl group, a propyl group, a butyl group, Alkyl group such as hexyl group; alkoxy group such as methoxy group, ethoxy group, butoxy group; allyl group; aralkyl group such as benzyl group, naphthylmethyl group, phenethyl group; phenoxy group,
Aryloxy group such as a triloxy group; an arylalkoxy group such as a benzyloxy group and a phenethyloxy group; an aryl group such as a phenyl group and a naphthyl group; an arylvinyl group such as a styryl group and a naphthylvinyl group, a dimethylamino group, a diethylamino group and the like Dialkylamino group; diphenylamino group; diarylamino group such as dinaphthylamino group; diaralkylamino group such as dibenzylamino group, diphenethylamino group; diheterocyclic amino group such as dipyridylamino group, dithienylamino group A diallylamino group, a disubstituted amino group in which the above-mentioned amino group substituents are combined, and the like.

B, D and E each represent a benzene ring which may have one or more substituents, and the substituents include halogen atoms such as chlorine atom, bromine atom and iodine atom; methyl group;
Alkyl groups such as ethyl group and propyl group; alkoxy groups such as methoxy group, ethoxy group and propyloxy group; aryl groups such as phenyl group and naphthyl group; dialkylamino groups such as dimethylamino group and diarylamino groups such as diphenylamino group Group, a diaralkylamino group such as a dibenzylamino group; a diheterocyclic amino group such as a dipyridylamino group, a diallylamino group, or a substituted amino group such as a disubstituted amino group which is a combination of the above-mentioned amino group substituents. And these may be the same or different from each other, in particular, a hydrogen atom,
A methyl group and a methoxy group are preferred. These alkyl group, alkoxy group and aryl group may have a substituent, and as the substituent, a hydroxyl group; a halogen atom such as a chlorine atom, a bromine atom or an iodine atom; a methyl group, an ethyl group or a propyl group Groups, butyl groups, hexyl groups, and other alkyl groups; methoxy groups, ethoxy groups, butoxy groups, and other alkoxy groups; aryl groups; benzyl groups, naphthylmethyl groups, phenethyl groups, and other aralkyl groups; phenoxy groups, triloxy groups, and other aryl groups An oxy group; an arylalkoxy group such as a benzyloxy group and a phenethyloxy group; a phenyl group,
Aryl group such as naphthyl group; Divinylamino group such as styryl group, arylvinyl group such as naphthylvinyl group, dimethylamino group, diethylamino group; Diarylamino group such as diphenylamino group, dinaphthylamino group; Dibenzylamino group, Diaralkylamino groups such as diphenethylamino groups; diheterocyclic amino groups such as dipyridylamino groups and dithienylamino groups; diallylamino groups, and disubstituted amino groups in which the above amino group substituents are combined. .

R ¹ , R ² , R ³ , R ⁵ , R ⁶ , R ⁷ , R
⁸ and R ⁹ are each a hydrogen atom; an alkyl group such as a methyl group, an ethyl group or a propyl group; an aryl group such as a phenyl group, a naphthyl group or an anthracenyl group; a hetero group such as a pyrrolyl group, a thienyl group, a furyl group or a carbazolyl group. Represents a ring group. These alkyl group, aryl group and heterocyclic group may have a substituent, and as the substituent, a chlorine atom,
Halogen atom such as bromine atom, iodine atom; alkyl group such as methyl group, ethyl group, propyl group, butyl group, hexyl group; alkoxy group such as methoxy group, ethoxy group, butoxy group; allyl group; benzyl group, naphthyl Aralkyl groups such as methyl group and phenethyl group; aryloxy groups such as phenoxy group and triloxy group; arylalkoxy groups such as benzyloxy group and phenethyloxy group; phenyl group,
Aryl group such as naphthyl group, styryl group, aryl vinyl group such as naphthyl vinyl group, dialkylamino group such as dimethylamino group, diethylamino group; diarylamino group such as diphenylamino group, dinaphthylamino group; dibenzylamino group, Diaralkylamino groups such as diphenethylamino groups; diheterocyclic amino groups such as dipyridylamino groups and dithienylamino groups; diallylamino groups, and disubstituted amino groups in which the above amino group substituents are combined. .

When n is 2 or more, each R ¹ and R ²
May be the same or different. R ⁴ is an alkyl group such as a methyl group, an ethyl group or a propyl group; an aryl group such as a phenyl group, a naphthyl group or an anthracenyl group; a heterocyclic group such as a pyrrolyl group, a thienyl group, a furyl group or a carbazolyl group; a benzyl group; It represents an aralkyl group such as a phenethyl group and is preferably an alkyl group. These alkyl group, aryl group, heterocyclic group and aralkyl group may have a substituent, and examples of the substituent include a halogen atom such as chlorine atom, bromine atom and iodine atom; methyl group, ethyl group, Alkyl groups such as propyl group, butyl group, hexyl group; alkoxy groups such as methoxy group, ethoxy group, butoxy group; allyl group; aralkyl groups such as benzyl group, naphthylmethyl group, phenethyl group; phenoxy group, triloxy group, etc. Aryloxy group; arylalkoxy group such as benzyloxy group and phenethyloxy group; aryl group such as phenyl group and naphthyl group; arylvinyl group such as styryl group and naphthylvinyl group; dialkylamino group such as dimethylamino group and diethylamino group; Diaralkylamino groups such as diphenylamino group and diphenethylamino group;
Examples thereof include diheterocyclic amino groups such as dipyridylamino group and dithienylamino group; diallylamino groups, and disubstituted amino groups in which the above-mentioned amino group substituents are combined.

R ^{10 and} R ¹¹ are each an aryl group such as a phenyl group, a naphthyl group and an anthracenyl group; a heterocyclic group such as a pyrrolyl group, a thienyl group, a furyl group and a carbazolyl group; a methyl group, an ethyl group, a propyl group and the like. An alkyl group of
An aralkyl group such as a benzyl group and a phenethyl group; an allyl group. These aryl group, heterocyclic group, alkyl group and aralkyl group may have a substituent, and examples of the substituent include halogen atoms such as chlorine atom, bromine atom and iodine atom; methyl group, ethyl group, Propyl group, butyl group,
Alkyl group such as hexyl group; methoxy group, ethoxy group,
Alkoxy group such as butoxy group; allyl group; benzyl group,
Aralkyl groups such as naphthylmethyl group and phenethyl group; aryloxy groups such as phenoxy group and triloxy group; arylalkoxy groups such as benzyloxy group and phenethyloxy group; aryl groups such as phenyl group and naphthyl group, styryl group, naphthylvinyl group Groups such as aryl vinyl groups, dimethylamino groups, diethylamino groups such as dialkylamino groups; difetylamino groups, dinaphthylamino groups, etc. diarylamino groups; dibenzylamino groups, diphenethylamino groups, etc., diaralkylamino groups A diheterocyclic amino group such as a dipyridylamino group and a dithienylamino group; a diallylamino group; and a disubstituted amino group in which the above-mentioned amino group substituents are combined. Especially among R ¹⁰ and R ¹¹ ,
At least one is preferably an aryl group which may have a substituent.

R ¹⁰ and R ¹¹ may be connected directly or via a bonding group. As the bonding group, an alkylene group such as a methylene group, an ethylene group or a trimethylene group;
A hetero atom such as —S—, —O—, or —N—;
In particular -S -, - O -, - CH ₂ - are preferred, and further -
S- is preferred. Examples of preferred Q when R ¹⁰ and R ¹¹ are linked via a bonding group include the following general formula [V],
Examples include [VI], [VII], and [VIII].

[0023]

[Chemical 5]

(F and G are each a halogen atom as a substituent, an alkyl group which may have a substituent,
It represents an alkoxy group which may have a substituent, an aryl group which may have a substituent or a benzene ring which may have a substituted amino group, and these may be the same or different from each other. ) Representative examples of the arylamine hydrazone compounds represented by the general formula [I] will be given below. However, these representative examples are shown for the purpose of illustration. It is not limited to the example.

[0025]

[Chemical 6]

[0026]

[Chemical 7]

[0027]

[Chemical 8]

[0028]

[Chemical 9]

[0029]

[Chemical 10]

[0030]

[Chemical 11]

[0031]

[Chemical 12]

[0032]

[Chemical 13]

[0033]

[Chemical 14]

[0034]

[Chemical 15]

[0035]

[Chemical 16]

[0036]

[Chemical 17]

[0037]

[Chemical 18]

[0038]

[Chemical 19]

[0039]

[Chemical 20]

The arylamine hydrazone compound represented by the general formula [I] can be produced by a known method. As a preferred production method, (1) A is represented by the general formula [I
In the case of the group represented by I] and (2) A is represented by the general formula [III]
The case of the group represented by and the case of (3) A is the group represented by the general formula [IV] will be described respectively. (1) When A is a group represented by the general formula [II] For example, a known arylamine compound is used to carry out a known carbonyl-introducing reaction, and then a known etherification reaction is carried out, and then a desired number of times is known. The Wittig reaction and a known carbonyl introduction reaction are sequentially performed, and a dehydration reaction with a desired hydrazine compound is performed to obtain the target compound. To explain this method in detail, first of all,

[0041]

[Chemical 21]

When R ¹ = H: General formula [X] (in the general formulas [X] and [XI], B, D,
E and R ¹ have the same definition as in formula [I]. ) In the presence of phosphorus oxychloride, an arylamine compound represented by the formula N, N-dimethylformamide, N
-Reaction with a formylating agent such as methylformanilide gives an aldehyde derivative represented by the general formula [XI]. The formylating agent may be used in a large excess to serve as the reaction solvent, but an inert solvent for the reaction such as O-dichlorobenzene or benzene may be used.

In the case of R ¹ ≠ H, the arylamine compound represented by the general formula [X] is generally treated in the presence of a Lewis acid such as aluminum chloride, iron chloride or zinc chloride in a solvent such as nitrobenzene, dichloromethane or carbon tetrachloride. A ketone body represented by the general formula [XI] is obtained by reacting with an acid chloride represented by the formula Cl-CO-R ¹ . (Carbonyl introduction reaction) Then, an arylamine compound represented by the general formula [XI] and a general formula W-
X-Ar (W represents a halogen atom such as a chlorine atom, a bromine atom and an iodine atom, Ar and X are the same as those in the general formula [I]), and potassium hydroxide or hydroxide By reacting in the presence of a base such as sodium, pyridine or triethylamine in a solvent inert to the reaction such as toluene, benzene, tetrahydrofuran, dioxane or N, N-dimethylformamide, the compound of the general formula [XII] (the general formula [XII] Medium, B, D, E and R ¹
Has the same definition as in formula [I]. An arylamine compound represented by (Etherification reaction)

[0044]

[Chemical formula 22]

Next, the arylamine compound represented by the general formula [XII] and the general formula [R ₂ —CH ₂ PPh ₃ ] ⁺ w
^- (W represents a halogen atom such as chlorine atom, bromine atom, iodine atom and the like, Ph represents a phenyl group), and N, N in the presence of a base such as sodium methoxide or sodium hydride. By reacting in a solvent inert to the reaction such as dimethylformamide, dioxane, toluene, benzene, tetrahydrofuran or the like, the compound of the general formula [XIII] (in the general formula [XIII], B, D, E and R ¹ are I] has the same definition as in).
An arylamine compound represented by is obtained. (Wi
(ttig reaction)

[0046]

[Chemical formula 23]

In the case of n ≧ 2, the arylamine compound represented by the general formula [XIII] is subjected to the above-mentioned carbonyl introduction reaction and then the above-mentioned Wittig reaction (n-1) times to carry out the general formula [ XIV] (in the general formula [XIV], B, D, E, R ¹ , R ² and n have the same definitions as those in the general formula [I]), and thus an arylamine compound is obtained.

[0048]

[Chemical formula 24]

Then, the arylamine compound represented by the general formula [XIV] is subjected to the above-mentioned carbonyl introduction reaction to give the general formula [XV] (in the general formula [XV],
B, D, E, R ¹ , R ² , R ³ and n are represented by the general formula [I]
Has the same definition as in. An arylamine compound represented by

[0050]

[Chemical 25]

Then, the arylamine compound represented by the general formula [XV] is subjected to a dehydration condensation reaction with the hydrazine represented by the general formula H ₂ NQ to give an arylamine hydrazone compound represented by the general formula [I]. Is obtained.

[0052]

[Chemical formula 26]

The dehydration condensation reaction may be carried out at a temperature of 50 ° C. to 1 if necessary.
Under heating at 50 ° C., in a solvent inert to the reaction such as methanol, ethanol, tetrahydrofuran, cellosolve, N, N-dimethylformamide, benzene and toluene,
Paratoluenesulfonic acid as a reaction accelerator, if desired,
You may use auxiliary agents, such as hydrochloric acid and sodium acetate. (Hydrazone reaction)

(2) When A is a group represented by the general formula [III] For example, a known arylamine compound is used to carry out a known carbonyl introduction reaction, and a desired number of known wit
In this method, the desired compound is obtained by sequentially performing a tig reaction and a known carbonyl introduction reaction, then a known esterification reaction, and then a dehydration reaction with a desired hydrazine compound.

This method will be described in detail. Using the arylamine compound represented by the general formula [XI] obtained by the above-mentioned carbonyl-introducing reaction, the above-mentioned Wittig reaction and the above-mentioned carbonyl-introducing reaction are sequentially carried out a desired number of times. General formula [XVI] (in the general formula [XVI],
B, D, E, R ¹ , R ² , R ³ and n are represented by the general formula [I]
Has the same definition as in. ) Is obtained.

[0056]

[Chemical 27]

Then, the obtained arylamine compound represented by the general formula [XVI] is inactive in the reaction of toluene, benzene, tetrahydrofuran, dioxane, N, N-dimethylformamide or the like in the presence of a base such as pyridine or triethylamine. By reacting with an acid chloride represented by the general formula Cl-CO-R ⁴ in a general solvent [XV
II] (in the general formula [XVII], B, D, E, R ¹ , R ² , R
³ and n have the same definition as in general formula [I]. An arylamine compound represented by

[0058]

[Chemical 28]

Then, the arylamine compound represented by the general formula [XVII] is used to carry out the above-described hydrazone-forming reaction to obtain an arylamine hydrazone compound represented by the general formula [I]. (3) When A is represented by the general formula [IV] n = 0 For example, a known arylamine compound is used to carry out a known carbonyl-introducing reaction, and then a known etherification reaction. Is a method of obtaining the target compound by performing a dehydration reaction with hydrazines of.

This method will be explained in detail. The following general formula [XVIII obtained by the above-mentioned carbonyl introduction reaction is obtained.
[In the general formula [XVIII], B, D, E and R ³ have the same meanings as in the general formula [I].] And the arylamine compound represented by the general formula W-CR ⁵ R ⁶ -C.
R ⁷ = CR ⁸ R ⁹ (W represents a halogen atom such as a chlorine atom, a bromine atom or an iodine atom, and R ⁵ , R ⁶ , R ⁷ and R ⁸
And R ⁹ have the same definition as in formula [I]. By carrying out the above-mentioned etherification reaction using a halide represented by the formula: [XIV] (in the general formula [XIV], B, D, E, R ³ , R ⁵ , R ⁶ , R ⁷ ,
R ⁸ and R ⁹ have the same definition as in formula [I]. An arylamine compound represented by

[0061]

[Chemical 29]

Then, the arylamine compound represented by the general formula [XIV] is used to carry out the above-mentioned hydrazone-forming reaction to obtain an arylamine hydrazone compound represented by the general formula [I]. In the case of n ≧ 1 For example, a known arylamine compound is used to carry out a known carbonyl introduction reaction, and a known number of times of known wit
In this method, the target compound is obtained by sequentially performing a tig reaction and a carbonyl introduction reaction, and then performing a dehydration reaction with desired hydrazines.

This method will be described in detail. The arylamine compound represented by the general formula [XVI] and the halide represented by the general formula W-CR ⁵ R ⁶ -CR ⁷ = CR ⁸ R ⁹ are used. By performing the etherification reaction described above, by the general formula [XX] (in the general formula [XX],
B, D, E, R ¹ , R ² , R ³ , R ⁵ , R ⁶ , R ⁷ , R
⁸ and R ⁹ have the same definition as in formula [I]. ) Is obtained.

[0064]

[Chemical 30]

Next, the arylamine compound represented by the general formula [XX] is subjected to the above-mentioned hydrazone-forming reaction to obtain an arylamine hydrazone compound represented by the general formula [I]. In these reactions, in some cases, after the completion of each step, or after the completion of all the steps, a highly purified product can be obtained by a known purification means such as recrystallization purification, sublimation purification, column purification and the like.

The electrophotographic photoreceptor of the present invention has a photosensitive layer containing one or more arylamine hydrazone compounds represented by the above general formula [I]. The arylamine hydrazone compound represented by the general formula [I] exhibits extremely excellent performance as an organic photoconductor. In particular, when it is used as a charge transport medium, it gives a photoreceptor having high sensitivity and excellent durability.

Various forms of the photosensitive layer of the electrophotographic photosensitive member are known, and any of them may be used as the photosensitive layer of the electrophotographic photosensitive member of the present invention. For example, a photosensitive layer in which a dye such as an arylamine hydrazone compound and a sensitizer or an electron-withdrawing compound is added to a binder, photoconductive particles that generate charge carriers with extremely high efficiency when absorbing light, and an arylamine Photosensitive layer containing a hydrazone compound in a binder, charge transport layer consisting of an arylamine hydrazone compound and a binder, and photoconductive particles that generate charge carriers with extremely high efficiency when absorbing light, or consisting of this and a binder Examples thereof include a photosensitive layer in which a charge generation layer is laminated.

In these photosensitive layers, along with the arylamine hydrazone type compound represented by the general formula [I], other known arylamine compounds, hydrazone compounds and stilbene type compounds having excellent performance as an organic photoconductor are contained. Etc. may be mixed. In the present invention, when the arylamine hydrazone compound represented by the above general formula [I] is used in the charge transport layer of the photosensitive layer comprising the charge generation layer and the charge transport layer, the sensitivity is particularly high and the residual potential is high. It is possible to obtain a photosensitive member which is small and has little fluctuation in surface potential, decrease in sensitivity, accumulation of residual potential, and the like when repeatedly used or exposed to strong light.

In the electrophotographic photoreceptor of the present invention, the arylamine hydrazone compound represented by the above general formula [I] is dissolved in a suitable solvent together with a binder according to a conventional method.
Conducts a coating solution obtained by adding photoconductive particles, sensitizing dyes, electron-withdrawing compounds, or plasticizers, pigments and other additives that generate charge carriers with extremely high efficiency when absorbing light as needed. It can be manufactured by coating on a transparent support and drying it to form a photosensitive layer having a thickness of usually several μm to several tens μm, preferably 10 μm to 40 μm.
In the case of a photosensitive layer composed of two layers of a charge generation layer and a charge transport layer, the above-mentioned coating liquid is applied onto the charge generation layer, or the charge generation layer is applied onto the charge transport layer obtained by applying the above-mentioned coating liquid. It can be manufactured by forming.

As the solvent for adjusting the coating liquid, ethers such as tetrahydrofuran and 1,4-dioxane; ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene and xylene; N, N-dimethylformamide, acetonitrile, N-methylpyrrolidone,
Aprotic polar solvents such as dimethyl sulfoxide; esters such as ethyl acetate, methyl formate and methyl cellosolve acetate; solvents for dissolving arylamine hydrazone compounds such as chlorinated hydrocarbons such as dichloroethane and chloroform. Of course, it is necessary to select one that dissolves the binder from these. Further, as the binder, styrene, vinyl acetate, vinyl chloride,
Polymers and copolymers of vinyl compounds such as acrylic acid ester, methacrylic acid ester, butyene, polyvinyl acetal, polycarbonate, polyester, polysulfone, polyphenylene oxide, polyurethane, cellulose ester, cellulose ether, phenoxy resin, silicon resin, epoxy resin Examples include various polymers that are compatible with the styrene compound. The amount of binder used is usually based on the arylamine hydrazone compound,
It is in the range of 0.5 to 30 times by weight, preferably 0.7 to 10 times by weight.

Well-known photoconductive particles, dye pigments, and electron-withdrawing compounds can be used in the photosensitive layer. Photoconductive particles that generate charge carriers with extremely high efficiency when absorbing light include selenium, selenium-tellurium alloys, selenium-arsenic alloys, cadmium sulfide,
Inorganic photoconductive particles such as amorphous silicon; metal-containing phthalocyanine, perinone pigment, thioindigo, quinacridone, perylene pigment, anthraquinone pigment, azo pigment, bisazo pigment, trisazo pigment, tetrakis azo pigment, cyanine pigment And the like. In particular, when combined with a metal-containing phthalocyanine, the sensitivity to laser light is improved and an excellent photoreceptor having a small residual potential can be obtained.

Examples of the dyes include triphenylmethane dyes such as methyl violet, brilliant green and crystal violet, thiazine dyes such as methylene blue, quinone dyes such as quinizarine, cyanine dyes, pyrylium salts, thiabilylium salts and benzopyrylium salts. Can be mentioned. Examples of the electron-withdrawing compound that forms a charge transfer complex with the arylamine hydrazone compound include, for example, chloranil and 2,3-dichloro-1,4-
Quinones such as naphthoquinone, 1-nitroanthraquinone, 1-chloro-5-nitroanthraquinone, 2-chloroanthraquinone and phenanthrenequinone; aldehydes such as 4-nitrobenzaldehyde; 9-benzoylanthracene, indandione, 3,5-dinitro Benzophenone, 2,4,7-trinitrofluorenone, 2,
4,5,7-tetranitrofluorenone, 3,3 ',
Ketones such as 5,5′-tetranitrobenzophenone;
Acid anhydrides such as phthalic anhydride and 4-chloronaphthalic anhydride; tetracyanoethylene, terephthalalmalononitrile, 9-anthrylmethylidenemalononitrile, 4-nitrobenzalmalononitrile, 4- (p-nitrobenzoyloxy) ) Cyano compounds such as benzalmalononitrile; 3-benzalphthalide, 3- (α-cyano-p-nitrobenzal) phthalide, 3- (α-cyano-p-nitrobenzal) -4,5,6,7-tetrachlorophthali Examples thereof include electron-withdrawing compounds such as phthalides.

Further, the photosensitive layer of the electrophotographic photoreceptor of the present invention may contain a well-known plasticizer in order to improve film-forming property, flexibility and mechanical strength. Therefore, examples of the plasticizer added to the coating solution include phthalic acid esters, phosphoric acid esters, epoxy compounds, chlorinated paraffins, chlorinated fatty acid esters, and aromatic compounds such as methylnaphthalene. When the arylamine hydrazone compound is used as the charge transporting medium in the charge transporting layer, the coating solution may have the above composition, but the photoconductive particles, dye pigment, electron withdrawing compound, etc. may be removed or added in a small amount. Good. In this case, as the charge generation layer, a coating solution obtained by dissolving or dispersing the photoconductive particles in a solvent such as a binder polymer, an organic photoconductive substance, a dye pigment, or an electron-withdrawing compound as necessary is applied and dried. Examples thereof include a thin layer or a layer formed by forming the photoconductive particles by a method such as vapor deposition.

Further, the photosensitive layer of the electrophotographic photosensitive member of the present invention may contain a well-known additive in order to improve the electrical characteristics or the durability upon repeated use. Therefore, examples of the coating agent added to the coating liquid include phenol compounds, organic phosphorus compounds, organic sulfur compounds and the like. It goes without saying that the photoreceptor thus formed may also have an adhesive layer, an intermediate layer, a transparent insulating layer, etc., if necessary. As the conductive support on which the photosensitive layer is formed, any of those known in electrophotographic photoreceptors can be used. Specific examples thereof include metal drums such as aluminum, stainless steel, and copper, sheets, laminates of these metal foils, and vapor-deposited materials. Furthermore, a metal film, carbon black, copper iodide, a plastic film which has been subjected to a conductive treatment by applying a conductive substance such as a polymer electrolyte together with a suitable binder,
Examples include plastic drums, paper, paper tubes, and the like. Also,
Examples include conductive plastic sheets and drums containing conductive materials such as metal powder, carbon black, and carbon fibers.

[0075]

The electrophotographic photosensitive member of the present invention has a very high sensitivity and a small residual potential which causes fogging, and in particular, since light fatigue is small, accumulation of residual potential due to repeated use and strong exposure, It is characterized by small changes in surface potential and sensitivity and excellent durability.

[0076]

EXAMPLES Next, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following production examples and examples as long as the gist thereof is not exceeded. In the examples, "part" means "part by weight". (Production Example 1) (p-hydroxy) diphenylamine

[0077]

[Chemical 31]

5.2 g of N, N-dimethylformamide was dissolved in 20 ml, and then 5.5 m of phosphorus oxychloride.
1 was added, and then the mixture was reacted at 65 ° C. for 5 hours. After cooling down,
The reaction solution was discharged into 100 ml of ice water, hydrolyzed with sodium hydroxide, and then subjected to extraction, concentration and purification treatment by a conventional method to obtain 5.4 g of a formyl compound represented by the following structural formula.

[0079]

[Chemical 32]

2.0 g of the obtained formyl compound, 1.3 g of α-bromo-p-xylene and 0.2 g of tetra-n-butylammonium bromide were dissolved in 20 ml of tetrahydrofuran, and 0.6 g of potassium hydroxide was added,
The reaction was carried out at 0 ° C for 2 hours. After allowing to cool, the reaction solution is cooled to 100 ml of ice water.
It is discharged into a liquid, extracted, concentrated and purified by a conventional method, and the arylamine compound represented by the following structural formula 2.
5 g was obtained.

[0081]

[Chemical 33]

Then, 2.3 g of triphenylphosphine
Was dissolved in 10 ml of N, N-dimethylformamide, and 1.9 g of methyl iodide was gradually added dropwise to form a phosphonium salt, 2.5 g of the obtained arylamine compound was added, and sodium methylate 0 After adding 1.9 g little by little, it was made to react at 50 degreeC for 2 hours. After cooling down,
The reaction solution was discharged into 50 ml of ice water, and extracted, concentrated and purified by a conventional method to obtain 2.1 g of an arylamine compound represented by the following structural formula.

[0083]

[Chemical 34]

2.1 g of the obtained arylamine compound was dissolved in 23 ml of N, N-dimethylformamide, 0.6 ml of phosphorus oxychloride was added, and then the mixture was reacted at 60 ° C. for 3 hours. After allowing to cool, the reaction solution was discharged into 50 ml of ice water, hydrolyzed with sodium hydroxide, and then subjected to extraction, concentration, and purification treatments by a conventional method to obtain an arylamine compound represented by the following structural formula 2. 1 g was obtained.

[0085]

[Chemical 35]

Next, 2.1 g of the obtained arylamine compound and 1.4 g of 1,1-diphenylhydrazine were added to 30 ml of tetrahydrofuran and 2 ml of methanol under the acetic acid catalyst.
Reaction was carried out at 60 ° C. for 5 hours in a mixed solution of 5 ml. After cooling, the reaction solution was discharged into 150 ml of ice water, and extracted, concentrated and purified by a conventional method to give yellow crystals (m.p.
p. 159-161 degreeC) 2.8g was obtained. According to the following elemental analysis values and infrared absorption spectrum (FIG. 1), this compound was identified as No. It was found to be an arylamine hydrazone compound represented by the structural formula of 4.

[0087]

[Table 1] (Elemental analysis value) C ₄₁ H ₃₅ N ₃ O C% H% N% Calculated value 84.07 6.02 4.78 Measured value 83.98 6.00 4.73 (Mass spectrometry measurement result) ) As C ₄₁ H ₃₅ N ₃ O, Mw = 585 M ⁺ = 585

(Production Example 2) Triphenylphosphine 2.
7 g was dissolved in 7 ml of N, N-dimethylformamide,
Then, 2.1 g of methyl iodide was gradually added dropwise. Then, 2.0 g of the formyl compound obtained in the middle of Preparation Example 1 was added, and a 28% methanol solution of sodium methylate was added.
7 g was gradually added dropwise. Then, it was made to react at 50 degreeC for 2 hours. After cooling, the reaction solution was discharged into 100 ml of ice water and subjected to extraction, concentration and purification treatments by a conventional method to give the arylamine compound 1.
8 g was obtained.

[0089]

[Chemical 36]

Next, 1.8 g of the obtained arylamine compound was dissolved in 20 ml of N, N-dimethylformamide, and then 2.8 g of phosphorus oxychloride was added to 60 ° C.
And reacted for 3 hours. After cooling, the reaction solution was discharged into 50 ml of ice water, hydrolyzed with sodium hydroxide, and then subjected to extraction, concentration and purification treatments by a conventional method.
1.9 g of an arylamine compound represented by the following structural formula
Got

[0091]

[Chemical 37]

Then, 1.9 g of the obtained arylamine compound and 1.0 ml of pyridine were dissolved in 30 ml of toluene, and 0.5 ml of enanthyl chloride was gradually added dropwise. Then, it was made to react at 80 degreeC for 2 hours. After cooling, the mixture was discharged into 100 ml of ice water, extracted, concentrated and purified by a conventional method to obtain 2.0 g of an arylamine compound represented by the following structural formula.

[0093]

[Chemical 38]

Next, 2.0 g of the obtained arylamine compound was reacted with 1.3 g of 1,1-diphenylhydrazine in a mixed solution of 30 ml of tetrahydrofuran and 25 ml of methanol under an acetic acid catalyst at 60 ° C. for 5 hours. After cooling, the reaction solution was discharged into 150 ml of ice water, and extracted, concentrated, and purified by a conventional method to give a yellow oily substance 2.
3 g was obtained. According to the following elemental analysis values and infrared absorption spectrum diagram, this compound was identified as No. It was found to be an arylamine hydrazine compound represented by the structural formula of 19.

[0095]

[Table 2] (Elemental analysis value) C ₄₀ H ₃₉ N ₃ O ₂ C% H% N% Calculated value 80.91 6.62 7.08 Measured value 80.86 6.59 7.06 (Mass spectrometry measurement Results) As C ₄₀ H ₃₉ N ₃ O ₂ , Mw = 593 M ⁺ = 593

(Production Example 3) 2.0 g of the formyl compound obtained in the course of Production Example 1, 0.9 g of allyl bromide and 0.2 g of tetra-n-butylammonium bromide.
Was dissolved in 20 ml of tetrahydrofuran, 0.6 g of potassium hydroxide was added, and the mixture was reacted at 60 ° C. for 2 hours. After allowing to cool, the reaction liquid was discharged into 100 ml of ice water, and extracted, concentrated and purified by a conventional method to obtain 2.2 g of an arylamine compound represented by the following structural formula.

[0097]

[Chemical Formula 39]

Next, 2.2 g of the obtained arylamine compound and 1.9 g of 1,1-diphenylhydrazine were treated with acetic acid catalyst in 40 ml of tetrahydrofuran and 3 ml of methanol.
The reaction was carried out in 0 ml of a mixed solvent at 60 ° C for 5 hours. After cooling, the reaction solution was discharged into 200 ml of ice water, and extracted, concentrated and purified by a conventional method to give yellow crystals (m.p.
p. 123-124.5 ° C) 3.1 g was obtained. According to the following elemental analysis value and infrared absorption spectrum diagram (FIG. 2), this compound No. It was found to be an arylamine hydrazone compound represented by the structural formula 29.

[0099]

[Table 3] (Elemental analysis value) C ₃₄ H ₂₉ N ₃ O C% H% N% Calculated value 82.40 5.90 8.48 Measured value 82.29 5.88 8.45 (Mass spectrometry measurement result) ) As C ₃₄ H ₂₉ N ₃ O, Mw = 495 M ⁺ = 495

Production Example 4 The arylamine compound 1.9 obtained in the course of Production Example 2 and 0.8 g of allyl bromide.
And tetra-n-butylammonium bromide.
2g was melt | dissolved in 20 ml of tetrahydrofuran, 0.7g of potassium hydroxide was added, and it was made to react at 60 degreeC for 2 hours. After cooling, the reaction solution was discharged into 100 ml of ice water and extracted, concentrated and purified by a conventional method to obtain 2.1 g of an arylamine represented by the following structural formula.

[0101]

[Chemical 40]

Next, 2.1 g of the obtained arylamine compound and 1.9 g of 1,1-diphenylhydrazine were added to 40 ml of tetrahydrofuran and 3 ml of methanol under the acetic acid catalyst.
The reaction was carried out in 0 ml of a mixed solvent at 60 ° C for 5 hours. After cooling, the reaction solution was discharged into 200 ml of ice water, and extracted, concentrated and purified by a conventional method to give yellow crystals (m.p.
p. (78-80 ° C.) 2.2 g was obtained. According to the following elemental analysis values and infrared absorption spectrum diagram (FIG. 3), this compound was identified as No. It was found to be an arylamine hydrazone compound represented by the structural formula of 43.

[0103]

[Table 4] (Elemental analysis value) C ₃₆ H ₃₁ N ₃ O C% H% N% Calculated value 82.90 5.99 8.06 Measured value 82.20 5.97 8.05 (Mass spectrometry measurement result) ) As C ₃₆ H ₃₁ N ₃ O, Mw = 521 M ⁺ = 521

Example 1 In the X-ray diffraction spectrum, the Bragg angle (2θ ± 0.2 °) 9.3 °, 10.6
°, 13.2 °, 15.1 °, 15.7 °, 16.1
Titanium oxyphthalocyanine pigment 1.0 showing strong diffraction peaks at 2 °, 20.8 °, 23.3 ° and 27.1 °
Parts to 14 parts of dimethoxyethane and dispersed with a sand grinder, then 14 parts of dimethoxyethane and 4-part
Methoxy-4-methylpentanone-2 (Mitsubishi Kasei Co., Ltd.)
(Manufactured by the company) and diluted with 14 parts, and further 0.5 parts by weight of polyvinyl butyral (manufactured by Denki Kagaku Kogyo KK, trade name Denka Butyral # 6000-C) and phenoxy resin (manufactured by Union Carbide Co., Ltd., Trade name: UCAR (registered trademark) PKHH) 0.5 parts dimethoxyethane 6 parts, 4-
Mixing was performed with a liquid dissolved in a mixed solvent of 6 parts of methoxy-4-methylpentanone-2 to obtain a dispersion liquid. This dispersion is 7
The amino vapor deposition layer vapor-deposited on a polyester film having a thickness of 5 μm was coated with a wire bar so that the weight after drying was 0.4 g / m ² , and then dried to form a charge generation layer. 70 parts of the arylamine hydrazone compound prepared in Preparation Example 1 and the following polycarbonate resin

[0105]

[Chemical 41]

A coating solution prepared by dissolving 100 parts in a mixed solvent of 585 parts of tetrahydrofuran and 315 parts of dioxane was applied and dried to form a charge transport layer having a film thickness of 17 μm.
When the sensitivity, that is, the half-exposure amount was measured with the electrophotographic photosensitive member having the photosensitive layer composed of two layers thus obtained, it was 0.49 μJ / cm ² .

The half-exposure amount is 50 μm in the dark.
780 nm obtained by negatively charging by corona current of A and then passing 20 lux white light through an interference filter
It was determined by measuring the amount of exposure required to attenuate the surface potential from -450V to -225V by exposing to light (exposure energy 10 μW / cm ² ). Furthermore, when the surface potential when the exposure time was set to 9.9 seconds was measured as the residual potential, it was -4V. This operation was repeated 2000 times, but no increase in residual potential was observed.

The surface potential when the photoreceptor was negatively charged with a corona current of 50 μA in the dark was set to V ₀ , and the photoreceptor was irradiated with white light of 3000 lux for 5 minutes, and then similarly negatively charged. The surface potential at time is V, and (V / V ₀ )
When x100 (%) was determined as the strong exposure retention rate, it was 9
It was 2.1%. Furthermore, negative charging-exposure process 1
The surface potential when negatively charged after repeating 00 times is V ′
Then, (V ′ / V ₀ ) × 100 (%) was determined as the strong exposure recovery rate, and it was 93.5%.

Example 2 Instead of the titanium oxyphthalocyanine pigment used in Example 1, in the X-ray diffraction spectrum, the Bragg angle (2θ ± 0.2 °) was 9.5 °,
Example 1 except that a titanium oxyphthalocyanine pigment showing strong diffraction peaks at 27.1 ° and 27.3 ° was used.
The half-exposure amount of the photoconductor prepared in the same manner as above was exposed to light having a wavelength of 780 nm and was 0.12 μJ / cm ² . The residual potential is -5 V, and the strong exposure retention rate is 9
The recovery rate for strong exposure to light was 1.3% and 92.8%.

(Example 3) A photoconductor prepared in the same manner as in Example 1 except that a naphthalic acid-based bisazo pigment represented by the following structural formula was used in place of the phthalocyanine-based pigment used in Example 1 was subjected to white light. It was 0.78 lux.sec. The residual potential was -5 V, the strong exposure retention rate was 90.5%, and the strong exposure recovery rate was 91.6%.

[0111]

[Chemical 42]

(Example 4) A photoconductor prepared in the same manner as in Example 1 except that a naphthalic acid-based bisazo pigment represented by the following structural formula was used in place of the phthalocyanine-based pigment used in Example 1 was treated with white light. It was 0.99 lux.sec. The residual potential was -8 V, the strong exposure retention rate was 90.3%, and the strong exposure recovery rate was 92.0%.

[0113]

[Chemical 43]

(Examples 5 to 12) Instead of the arylamine hydrazone compound used in Example 1, Production Examples 1 to
The sensitivity, residual potential and strong exposure retention of the electrophotographic photosensitive member prepared in the same manner as in Example 1 except that the arylamine hydrazone compounds shown in Table 1 below, which were synthesized in the same manner as in Example 4, were used. Show.

[0115]

[Table 5] Table 1 Example Example Compound No. Sensitivity (μJ / cm ² ) Residual potential (V) Strong exposure retention rate (%) 5 12 0.50 -5 91.8 6 14 0.49 -4 90. 3 7 18 0.56 -10 92.1 8 22 0.58 -9 91.5 9 29 0.47 -3 91.1 10 30 0.48 -5 92.0 11 39 39 0.51 -7 91. 7 12 43 0.45 -2 92.2

(Examples 13 to 20) Instead of the arylamine hydrazone compound used in Example 3, Production Example 1
Table 4 shows the sensitivity, residual potential and strong exposure holding ratio of the electrophotographic photosensitive member prepared in the same manner as in Example 3 except that the arylamine hydrazone compounds shown in Table 2 below were used. Shown in.

[0117]

[Table 6] Table 2 Example Compound No. Sensitivity (lux · sec) Residual potential (V) Strong exposure retention rate (%) 13 12 0.81 -6 91.0 14 14 0.79 -5 90.8 15 18 0.90-11 93.0 16 22 0.95-10 92.4 17 29 29 0.83 -4 90.7 18 30 0.82-5 91.9 19 39 39 0.85-12 90.5 20 43 0.76 -4 91.4

Comparative Example 1 An electrophotographic photosensitive member was obtained in the same manner as in Example 1 except that Comparative Compound 1 shown below was used instead of the arylamine hydrazone compound used in Example 1. Comparative compound 1

[0119]

[Chemical 44]

Then, in the same manner as in Example 1, the sensitivity, residual potential and strong exposure retention rate were measured. The results are shown in Table 3 together with the measurement results for the photoconductor of Example 1. (Comparative Example 2) A photoconductor was prepared in the same manner as in Comparative Example 1 except that Comparative Compound 2 shown below was used instead of Comparative Compound 1 used in Comparative Example 1, and the sensitivity, residual potential and strong exposure holding ratio were measured. It was measured. The results are shown in Table 3. Comparative compound 2

[0121]

[Chemical formula 45]

Comparative Example 3 A photoconductor was prepared in the same manner as in Comparative Example 1 except that Comparative Compound 3 shown below was used in place of Comparative Compound 1 used in Comparative Example 1, and sensitivity, residual potential and strong exposure were used. The retention rate was measured. The results are shown in Table 3. Comparative compound 3

[0123]

[Chemical formula 46]

[0124]

[Table 7] Table 3 Example Sensitivity (μJ / cm ² ) Residual potential (V) Strong exposure retention rate (%) Comparative Example 1 0.60-27 85.9 Comparative Example 2 0.59-12 90.0 Comparative Example 3 0.59-11 81.3 Example 1 0.49-4 92.1

It is apparent from Table 3 that the compound of Example 1 shows superior numerical values in terms of sensitivity, residual potential and strong exposure holding ratio as compared with the compounds of Comparative Examples 1, 2 and 3. Recognize.

[Brief description of drawings]

FIG. 1 is an infrared absorption spectrum diagram of an arylamine hydrazone compound obtained in Production Example 1.

FIG. 2 is an infrared absorption spectrum diagram of the arylamine hydrazone compound obtained in Production Example 3.

FIG. 3 is an infrared absorption spectrum diagram of the arylamine hydrazone compound obtained in Production Example 4.

Claims (1)

[Claims] 1. A structure represented by the following general formula [I] on a conductive support.
Containing an arylamine hydrazone compound
An electrophotographic photoreceptor having a photosensitive layer. [Chemical 1]n is a group represented by the general formula [II] or [III]
Is an integer of 1 or more, and A is represented by the general formula [IV]
When it is a group, it is 0 or an integer of 1 or more, X represents an alkylene group which may have a substituent; Ar
Has an aryl group which may have a substituent or has a substituent
Represents a heterocyclic group which may be present; B, D and E are respectively
Represents a benzene ring which may have one or more substituents,
May be the same or different from each other; R¹, R²，
R³, R^Five, R⁶, R⁷, R⁸And R⁹Respectively
Hydrogen atom, an alkyl group which may have a substituent, a substituent
Optionally substituted aryl group, optionally substituted heterocycle
Represents a group, and when n is 2 or more, in each structural unit
R ¹Each may be different, R²As well
R; R^FourIs an alkyl group which may have a substituent, a substituent
Optionally substituted aryl group, optionally substituted heterocycle
Represents an aralkyl group which may have a group or a substituent;
R^TenAnd R¹¹Are each optionally substituted
Reel group, optionally substituted heterocyclic group, or substituted
Represents an aralkyl group or an allyl group which may be
R^TenAnd R¹¹Linked directly to or via a linking group
May be. )