JPH01186858A - Production of 4-alkylthio-substituted phenol compound - Google Patents

Abstract

PURPOSE:To obtain a compound useful as a synthetic intermediate for dye, agricultural chemical or medicine, cyan coupler in photographic chemical, etc., in one process and good yield, by reacting a phenol compound with an asymmetric disulfide in the presence of a base. CONSTITUTION:A phenol compound expressed by formula I or formula II (R1 is a group capable of substituting at aromatic ring and is not substituted at 4 position of phenol or naphthol; m is 0-4; n is 0-6) is reacted with an asymme tric disulfide expressed by formula III (R2 is aliphatic; X is O, S, Se, Te, N or methine; Y is N or methine; Z forms non-metallic atom group of 5 or 6-mem bered ring together with X and Y or may have condensed ring) in the presence of a base (e.g., NaOH) in a solvent such as N,N-dimethylformamide at -78-250 deg.C to provide the aimed product expressed by formula IV or formula V.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides 4-thio substituted phenol compounds, 4-alkylthio-1-phenol and 4-alkylthio-1
-This invention relates to a method for producing naphthol derivatives.

(Prior Art) 4-Alkylthio-1-phenol and 4-alkylthio-1-naphthol derivatives are important as synthetic intermediates for dyes and physiologically active compounds (medicines, agricultural chemicals, etc.).

Additionally, 4-thio-substituted-1-phenol and 4-thio-substituted-1-naphthol derivatives are known in the field of photochemistry as 2-equivalent base cyan color-forming couplers. For example, U.S. Pat. Japanese Patent Publication No. 60-5053
Examples can be found in No. 3, No. 60-91355, No. 61-201247, and No. 62-173467. By the way, 4-thio-substituted-1-phenol and 4-
Among the thio-substituted-1-naphthol derivatives, compared to 4-heterocyclic thio-1-phenol, 4-heterocyclic thio-1-naphthol, 4-arylthio-1-phenol and 4-arylthio-1-naphthol derivatives There are not many known examples of 4-alkylthio-1-naphthol derivatives being actually used, and the main reason for this is the difficulty of synthesis or the low synthesis yield.

On the other hand, conventionally, a method using arylsulfenyl chloride has been generally used as a method for introducing an arylthio group into the 4-position of 1-phenol and 1-naphthol derivatives.

(U.S. Patent No. 3,227,551:
554) This arylsulfenyl chloride is relatively stable and can therefore be used in one synthesis. On the other hand, alkylsulfenyl chloride has been considered difficult to use in synthesis due to its instability. Therefore, 1-
It has never been used as a method for alkylthiolation at the 4-position of phenol and 1-naphthol.

To date, only the following two methods are known for alkylthioating the 4-position of 1-phenol and 1-naphthol.

That is, when disulfur dichloride is applied to l-naphthol or 1-phenol, a mixture of the corresponding sulfide, disulfide, and trisulfide is obtained. Reduction of disulfide and J trisulfide with summer lead gives the corresponding mercaptan. 4-Alkylthio-1-naphthol can be synthesized by reaction with an alkyl halide in the presence of a base (U.S. Patent No. 3,479,407: New Experimental Chemistry Course■.

1740; Chew, ^bgtr,, 72.31
445 (1970) ) (X=(J, Br)
This is a reaction in which copper mercaptide (R5 is an alkyl group) is reacted with 4-herogenol-l-naphthol to form an alkylthion at the 4-position (Chem-Abstr, 53.1
6145 (1959)).

(Problems to be solved by the invention) However, in method (2), depending on the type of 1-naphthol, the reaction may not proceed at all or the yield may be low (New Experimental Chemistry Course M, 1740) and the purpose The disadvantage is that it requires a long number of steps to obtain the product.

Method (2) has the disadvantage that the yield is low because reduction occurs as a side reaction.

As described above, in the conventionally known synthesis method of 4-alkylthio-1-naphthol derivatives, 4-alkylthio-1-phenol or 4-naphthol derivatives with unsubstituted 4-position can be synthesized in good yield. Alkylthio
It is not possible to convert it into 1-naphthol derivatives.

Therefore, an object of the present invention is to provide a general synthetic method for obtaining 4-alkylthio-1-phenol or 4-alkylthio-1-naphthol derivatives in higher yields than the corresponding 1-phenol or 1-naphthol derivatives. be.

(Means for Solving the Problems) As a result of various studies to overcome the shortcomings of these conventional methods, the present inventor has developed a method in which a l-phenol or 1-naphthol derivative is reacted with an asymmetric disulfide in the presence of a base. It has been found that the corresponding 4-alkylthiol-1-phenol or 4-alkylthio-1-naphthol derivatives can be synthesized with good yield, and based on this knowledge, the present invention has been accomplished.

That is, the present invention provides a method for combining a phenol compound represented by formula (I-a)t or (I-b) (I-a) (I-b) and an asymmetric disulfide represented by general formula (n) with a base. A 4-thio-substituted phenol compound, which is obtained by reacting in the presence of a 4-thio-substituted phenol compound represented by the general formula (m-a) or (m-b) (m-a) (m-b) A manufacturing method is provided.

(In the formula, R1 represents a group that can be substituted on an aromatic ring.

4-position of phenol and 4-position of naphthol are not substituted. 0m represents an integer from 0 to 4, n represents an integer from 0 to 6, R2 represents an aliphatic group, X represents an oxygen atom,
represents a sulfur atom, a selenium atom, a tellurium atom, a nitrogen atom or a methine group, Y represents a nitrogen atom or a methine group,
2 represents a nonmetallic atomic group constituting a 5- or 6-membered ring together with X and Y, and 2 may further have a fused ring.) Next, general formulas (I-a), (I The compounds represented by -b) and (II) and the bases used in the reactions will be described in detail.

- In the compound represented by formula (I-a) or (I-b), R1 is a group that can be substituted on an aromatic ring, such as a halogen atom, an alkyl group, an alkenyl group, an aryl group, a carboxyl group, a sulfo group , hydroxyl group, cyano group, carbamoyl group, sulfamoyl group, ureido group, carbonamide group, sulfonamide group, alkoxy group, aryloxy group, heterocyclic group, amino group, alkylsulfonyl group, arylsulfonyl group, alkoxycarbonyl group, Aryloxycarbonyl group, alkoxysulfonyl group, aryloxysulfonyl group, sulfamoylamino group, alkoxycarbonylamino group, acyl group, nitro group, etc. 0m is an integer from 0 to 4, and when m is plural, A plurality of R1s may be the same or different, and a plurality of R1s may be bonded to each other to form an aromatic hydrocarbon ring, an aliphatic ring, or a heterocycle.
n is an integer from 0 to 6, and when n is multiple, multiple R1 may be the same or different, and multiple R1 may be bonded to each other to form an aromatic hydrocarbon ring, an aliphatic ring, or a heterocyclic ring. “It may form a ring.

In more detail, the exemplified groups for R1 above include those having further substituents, such as halogen atoms, alkyl groups, alkenyl groups, aryl groups, carpoxyl groups, Sulfo group, hydroxyl group, cyano group, carbamoyl group, sulfamoyl group, ureido group, carbonamide group, sulfonamide group,
Alkoxy group, aryloxy group, heterocyclic group, amino group, alkylsulfonyl group, arylsulfonyl group, alkoxycarbonyl group, aryloxycarbonyl group,
Examples include an alkoxysulfonyl group, an aryloxysulfonyl group, a sulfamoylamino group, an alkoxycarbonylamino group, an acyl group, and a nitro group.

In the compound represented by general formula (II), R2 represents an optionally substituted straight chain, branched chain, or cyclic alkyl group, alkenyl group, etc.;

Y and 2 are as described above.

The asymmetric disulfide represented by general formula (II) is (τ
+ Endo, H, τasss and T, Is
Higashi, Chew.

Lett,, 1975.813) and (T, M
ukaiyama and K, Takahaghi,
τetrahedron Latt,, 1968.5
It can be synthesized with good yield by the method described in 907).

- The substituents preferably used in the present invention for the compound represented by formula (I-a) or (I-b) are as follows. That is, R1 is a halogen atom (
fluorine atom, chlorine atom, bromine atom, iodine atom), alkyl groups having 1 to 19 carbon atoms (e.g. methyl, ethyl, i-
propyl, 7-butyl, trifluoromethyl, n-dodecyl, n-octadecyl), aralkyl groups having 1 to 19 carbon atoms (eg, benzyl, phenethyl), carboxyl groups, sulfo groups, hydroxyl groups, cyano groups.

Carbamoyl group having 1 to 37 carbon atoms (e.g., carbamoyl, N,N-dimethylcarbamoyl, N.

N-diethylcarbamoyl, N-methylcarbamoyl,
N-Butylcarbamoyl% N-cyclohexylcarbamoyl, N,N-diethylcarbamoyl, N-(2-carboxylethyl)carbamoyl, N-hexadecylcarbamoyl, N-dodecylcarbamoyl% N-(3-)'
decyloxypropyl)carbamoyl, N-(3-(2
, 4-di-1-pentylphenoxy)propyl]carbamoyl, N-[4-(2,4-di-t-pentylphenoxy)butylsulfmoyl), sulfamoyl group having 0 to 36 carbon atoms (e.g. sulfamoyl, N- Methylsulfamoyl, N-butylsulfamoyl, N,N-dimethylsulfamoyl, N,N-diethylsulfamoyl,
N-dodecylsulfamoyl, N-octadecylsulfamoyl), carbon amide groups having 1 to 36 carbon atoms (e.g. formamide group, acetamido group, trifluoroacetamide group, propionamide group, benzamide group, p
-Nitrobenzamide, n-1'decaneamide, n-octadecanamide, i-butanamide, t-butanamide, 2-ethylbexanamide, 2-(2,4-di-
t-pentylphenoxy)butanamide, trichloroacetamide.

p-chlorobenzamide, pentafluorobecizamito, 2-(2,4-di-t-pentylphenoxy)hexanamide%2-(2,4-di-1'pentylphenoxy)octanamide%z-(3 -pentadecylphenoxy)butanamide, 2-(4-dodecylphenylthio)octanamide, 2-(4-butanesulfonamidophenoxy)tetradecanamide, 2-(2,4-
di-t-octylphenoxy)octanamide, 2-
(2,4-di-t-pentylphenoxy)tetradecanamide, 2-(4-(p-hydroxybenzenesulfonyl)phenoxy)tetradecanamide, 2-(2-chloro-4-(3'-chloro-4'-hydroxy) Benzenesulfonyl)phenoxy)dodecaneamide% 2-(2-chloro-4-carboxylphenoxy)tetradecanamide, 2-(3-t-butyl-4-hydroxyphenoxy)tetradecanamide), sulfonamide group having 1 to 36 carbon atoms (e.g. methanesulfonamide, ethanesulfonamide, n-butanesulfonamide, trifluoromethanesulfonamide, benzenesulfonamide, p-)luenesulfonamide, phenylmethanesulfonamide,
n-hexadecanesulfonamide, n-octadecanesulfonamide, m-nitromethanesulfonamide, p-
dodecylbenzenesulfonamide), aryloxy groups having 6 to 36 carbon atoms (e.g. phenoxy, p-methylphenoxy, p-methoxyphenoxy, p-nitrophenoxy, 0-chlorophenoxy), alkoxy groups having 1 to 36 carbon atoms (e.g. Methoxy, ethoxy, methoxyethoxy, benzyloxy, 2-pyranoxy, n-butoxy, n
-dodecyloxy, n-octadecyloxy), an alkoxycarbonyl group having 2 to 36 carbon atoms (eg, methoxycarbonyl, ethoxycarbonyl, n-octylcarbonyl, n-octadecylcarbonyl), and an amino group.

Alkylamino groups having 1 to 36 carbon atoms (e.g. methylamino, dimethylamino, morpholino, n-octylamino), nitro groups, acyl groups having 1 to 36 carbon atoms (e.g. formyl, acetyl, benzoyl, propionyl, n-butyryl, cyclohexanecarbonyl, n-decanoyl, n
-octadecanoyl), alkoxycarbonylamino groups having 1 to 36 carbon atoms (e.g. methoxycarbonylamino,
Ethoxycarbonylamino, i-butoxycarbonylamino, benzyloxycarbonylamino.

n-butoxycarbonylamino, t-butoxycarbonylamino, n-octyloxycarbonylamino, 'n
-tcdecyloxycarbonylamino, n-octadecyloxycarbonylamino), ureido groups having 1 to 36 carbon atoms (e.g. ureido, N-methylureido, N-
Ethylureido, N-phenylureido, N-(p-cyanophenyl)ureido, N-(m-chloro-p-cyanophenyl)ureido, N-propanesulfonylphenylureido, N-butanesulfonylphenylureido,
N-(m,p-dichlorophenyl)ureido, N-(o
-chloro-p-cyanophenyl)ureido, N-(4-
cyanonaphthyl)ureido, N-(m-cyanophenyl)ureido, N-methanesulfonylphenylureido,
N-(p-chlorophenyl)ureido, N-(p-methylphenyl)ureido, and N-(m-methanesulfonamidophenyl)ureido) are each preferred.

The substituent R1 is preferably introduced at least at the 2- and 5-positions in the compounds of formulas (I-a) and (I-b).

Among the compounds represented by the general formula (I-a) or (I-b), those having the following structures (V), (V
I) is preferred.

Here, R1 has the same meaning as R1 described above. Ar represents an alkylcarbonamide, and the alkyl may be substituted; R'-N- represents a monosubstituted amino group; more specifically, an alkylcarbonamide, an arylcarbonamide, an alkoxycarbonylamino, an aryloxycarbonylamino, It represents alkanesulfonamide, arylsulfonamide, etc., and alkyl and aryl may be substituted.

R2 in the compound represented by general formula (n) is an alkyl group having 1 to 40 carbon atoms (for example, methyl, ethyl, n
-propyl, i-propyl, n-butyl, n-hexyl, n-octyl, t-butyl, n-1<decyl, n-
octadecyl, cyclohexyl, cyclohexylmethyl, oleyl, benzyl, phenethyl, propargyl, crotyl).

Alkenyl groups having 1 to 40 carbon atoms (e.g., vinyl, allyl, isopropenyl, 1-butenyl, 2-butenyl, 2
-methylallyl, 2-pentenyl, 2,4-cyclohexagenyl, styryl, cinnamyl, cyclohexenyl), and the number of carbon atoms in these groups is preferably in the range of 1 to 10. Furthermore, these groups include halogen atoms, nitro, cyano , hydroxyl, alkoxy, aryloxy, acyloxy, sulfonyloxy, carboxyl, carboxylic acid ester, carbamoyl, sulfo, sulfonic acid ester, sulfamoyl, alkylthio, arylthio, sulfonyl, acyl, amino, acylamino, sulfonamide, ureido, urethane, sulfinyl, It may be substituted with a substituent such as sulfenyl, mercapto, aryl, or heterocycle.

In general formula (II), when X and Y are both methine groups, typical preferred groups are phenyl and naphthyl groups, and when X and Y are not methine groups, specific examples include pyridyl, pyrrolyl, oxasilyl, thiazolyl, benzoxasilyl, benzthiazolyl, quinolyl,
These include furyl, thienyl, indolyl, pyrazinyl, and pyrimidinyl. These groups are the herogen atom, nitro.

Cyano, alkyl, hydroxy, alkoxy, aryloxy, acyloxy, sulfonyloxy, carboxy, carbodiate ester, carbamoyl, sulfo, sulfonate ester, sulfamoyl, alkylthio, arylthio, sulfonyl, acyl, amino, acylamino,
Sulfonamide, ureido, urethane, sulfenyl,
It may be substituted with mercapto, aryl, petero ring groups, etc.

As the base used in the present invention, bases used in ordinary organic reactions can be used. For example, sodium hydroxide, lithium, potassium hydroxide, lithium hydroxide, sodium carbonate, potassium carbonate, lithium carbonate, hydrogen carbonate. Sodium, potassium hydrogen carbonate, sodium hydride,
potassium hydride, lithium hydride, sodium amide,
Calcium oxide, barium oxide, potassium t-butoxy, guanidine, 1.8-diazabicyclo [5°4.0]
-7-undecene (DBU), 1,5-diazabicyclo[4,3,O] -5-nonene (DBN)% n-butyllithium, n-methyllithium, 5ec-butyllithium% i-butyllithium, t- Butyl lithium, i-
Propyllithium, methylmagnesium bromide, potassium trimethylsilyloxy, sodium acetate, triethylamine, pyridine, sodium methoxide, potassium methoxide, lithium methoxide.

Examples include sodium ethoxide. Among these bases, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium hydride, DBU, potassium trimethylsilyloxy, and the like are preferred.

Next, the reaction conditions of the present invention will be described in detail.

Solvents used in the reaction of the present invention include methylene chloride, chloroform% 1.2-dichloroethane, acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, N-methylpyrrolidone, tetrahydrofuran, dioxane, dimethoxyethane. , diglyme, diethyl ether, benzene, toluene, hexamethylphosphoryl triamide, sulfolane, diethyl carbonate, 1,3-dimethyl-2-imidazolitone, methanol, ethanol, isopropyl alcohol, ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, xylene, Examples include acetic acid and water,
Among them, N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, tetrahydrofuran, methanol, ethanol, etc. are preferred.

In the present invention, the molar ratio of the asymmetric disulfide represented by the general formula (n) to the compound represented by the general formula (I-a) or (I-b) is 0.01 to 1000,
Preferably 0.1-20, more preferably O,S-1
It is 0.0.

The reaction temperature is -78°C to 250°C, preferably -20°C to
The temperature is 200°C, more preferably -4°C to 160°C.

The reaction time is 1 minute to 72 hours, preferably 20 minutes to 36 hours, more preferably 30 minutes to 24 hours.

(Specific examples of compounds) Specific examples of compounds to which the method of the present invention is applied are shown below.
It is not limited to these.

- Specific examples of compounds represented by formula (I-a) or (I-b) are shown below, and the following structural formulas % -C(CH3)2CH2C(CH3)3 are respectively represented.

Ou (I-18) Ou (I-19) H (I-20) H H (I-24) UNI to F3 (υ (I-26) C,H,0CONH ^U (I-31) r■ 1 (I-32) OH (I-34) c+5l (st (company) (I-37) (I-38) OH (I-39) OH Cl-40) (I-44) (I-45) 0M OH (I-48) (I-49) OH (I-51) OH (I-52) OH ShiH3S31Nfl (I-54) ＾Sweet (I-55) 0 Cl-56) (ilc4H@0CONH (I-59) (I-61) R (I-63) 0 (I-64) H OM u Specific examples of compounds represented by general formula (n) t-C4H9
-3-3QC observation (■-2) C113υ - Specific examples of the compound represented by the formula (m-a) or (m-b) are shown below.

0M u 0 Sweet (II-6) 0M r■1 OI H 0■ u (II-13) 0 Kidney OI H H H H 0M U H 0M (II-30) (I-31) 0M (!l-33 ) H 0 rental u (I-37) H H (1-39)゛H (summer-40) (IN-41) (I-42) (II-43) (I-44) 0 sweet (IN-46) ) H ('l-47) (IN-48) H H H H (I[-53) u (II-55) H OH OH OH u (I[-61) 0M u (I-63) OH OH 5CH2COOCzHs (Ift-65) OH R (Effect of the invention) According to the present invention, an alkylthio group or an alkenylthio group is introduced into the 4-position of a phenol compound such as a 1-phenol or l-naphthol derivative to form a target 4-alkyl Alternatively, an alkenylthio-substituted phenol compound can be obtained in a good yield.According to the present invention, the synthesis process is completed in one step, so it is extremely suitable for industrial implementation.

(Example) Next, the present invention will be explained in more detail based on examples.

Example 1 (Synthesis of exemplified compound m-56) l-56 (2.64 g, 5.0 l-ol) under nitrogen stream
in tetrahydrofuran solution at room temperature.

Potassium carbonate (0-70 g, 10,0 mmol) was added, and after stirring for 5 minutes, compound 1-4 (1.38 g) was added.

5.0 ■■ ol) was added and heated under reflux for 5 hours. Add water and extract three times with ethyl acetate. The organic layer is washed with saturated aqueous sodium bicarbonate solution, water, and saturated brine, and dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure, and column chromatography (developing solvent: hexane: ethyl acetate = 4
:l) to give compound lll-56 (1.84g,
9.76°C, 62%) was obtained.

Example 2 (Synthesis of Exemplified Compound ■-67) Under nitrogen flow, 8 of l-56 (2.0 g, 3.8 ■■ product)
Potassium carbonate (288
After stirring for 5 minutes, compound If-6 (1.3 g, 4.2 mmol) was added and heated under reflux for 1 hour. Add water and extract three times with ethyl acetate.

The organic layer is washed with a saturated aqueous sodium bicarbonate solution, water, and saturated brine, and dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure, and the compound m-6 was purified by column chromatography (developing solvent: hexane: ethyl acetate - 4:1).
7 (2.2 g, 90%) was obtained.

Example 3 (Synthesis of exemplified compound m-a) I-6 (9.77 g, 15.0 mmol) under nitrogen stream
Potassium carbonate (2,
After stirring for 15 minutes, compound 11-14 (5.08 g, 16.5-mol) was added and heated under reflux for 1 hour. Add water and extract three times with ethyl acetate. The organic layer was diluted with saturated aqueous sodium bicarbonate solution, water,
Wash with saturated saline and dry with anhydrous sodium sulfate. The solvent was distilled off under reduced pressure, and the residue was purified by column chromatography (developing solvent: hexane:ethyl acetate = 3:1) to obtain compound m-6 (7.74 g, 68%).

Comparative Example 1 (Synthesis of Exemplified Compound 1-56) Disulfur dichloride (6.80 g) was added to a methylene chloride (500 complement) solution of Compound 1-56 (52.8 g, 0.1 mol) under a nitrogen stream.
, 0.05 mol) and heated under reflux for 12 hours. After cooling, water is added, extracted twice with methylene chloride, and the organic layer is dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure and purified by silica gel column chromatography (developing solvent: hexane: ethyl acetate = 4:1), but the desired disulfide was not obtained and the raw material was recovered. For this reason, it was impossible to synthesize exemplified compound m-56 by the conventional method using disulfur dichloride.

Comparative Example 2 (Synthesis of Exemplified Compound ■-56) Under nitrogen stream, 4
-bromo-5-isobutoxycarbonylamino-2-(
3-dodecyloxypropylaminocarbonyl)-1-
Copper mercaptide of 2-hydroxyethanethiol (18.5 g) in a solution of naphthol (60.8 g, 0.10 o1) in quinoline (200 ml) at room temperature.

Add a pyridine (10 supplement) solution of 0.11 O1),
Heat and stir at 80°C for 1 hour.

After cooling, 0.1N hydrochloric acid is added and extracted three times with ethyl acetate. The organic layer is washed with saturated brine and dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure, and silica gel column chromatography (developing solvent; hexane: ethyl acetate =
4:1), 5-isobutoxycarbonylamino-2-(3-dodecyloxypropylcarbamoyl)-1-naphthol (48.0 g, 91%) was recovered. In this way, the reduction of the herogen atom at the 4-position progresses, so the example compound ■
It was not possible to synthesize -56.

Claims (1)

[Claims] General formula ( I -a) or ( I -b) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ ( I - a) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ ( I - b) A phenol compound represented by the general formula (II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) Reacts with an asymmetric disulfide represented by the formula (II) in the presence of a base ▲There are mathematical formulas, chemical formulas, tables, etc.▼(III-a ) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (III-b) A method for producing a 4-thio substituted phenol compound, which is characterized by obtaining a 4-thio substituted phenol compound represented by the following. (In the formula, R_1 represents a group that can be substituted on the aromatic ring, and is not substituted at the 4-position of phenol or the 4-position of naphthol. m represents an integer from 0 to 4, and n represents an integer from 0 to 6. , R_2 represents an aliphatic group, X represents an oxygen atom, sulfur atom, selenium atom, tellurium atom, nitrogen atom or methine group, Y represents a nitrogen atom or a methine group, Z
represents a group of nonmetallic atoms that together with X and Y constitute a 5- or 6-membered ring. Moreover, Z may further have a condensed ring. )