JPH11116650A - Optically active aromatic isocyanate polymer or copolymer and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject (co)polymer having excellent optical physical properties and capable of being expected as an optical functional material by introducing an optically active ester group onto an aromatic group. SOLUTION: This polymer has, mainly, a unit of formula I R<1> is an optically active ester group of formula II [R<2> and R<3> are each a 6-14C monofunctional aromatic group or a 1-14C alkyl, with the proviso that R<2> and R<3> are each a different group; (n) is 0 or 1 and exhibiting number of methylene], e.g. a group of formula III} and has >=5 polymerization degree and has an optically active ester group at the side chain. The polymer consisting essentially of the unit of formula I can be obtained by subjecting, e.g. an optically active aromatic isocyanate to anionic polymerization in the presence of a polymerization initiator. The polymer includes also a copolymer consisting essentially of the unit of formula I and a unit of formula IV (R<4> is a 1-14C alkyl or a 6-14c monofunctional aromatic group) and having >=5 polymerization degree.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a polymer or copolymer of an optically active aromatic isocyanate and a method for producing the same. The optically active aromatic isocyanate polymer or copolymer has a large optical rotation, and can be expected as an optically functional material such as a material for separating an optically active substance.

[0002]

2. Description of the Related Art Many optically active synthetic macromolecular substances used as functional materials such as optical resolving agents, liquid crystals, and nonlinear optical materials have been known. For example, JP-A-56-106907 discloses an optically active polymer of triphenylmethyl methacrylate, which has a helical structure, exhibits a high optical rotation, and is useful as an optical resolving agent. It is stated that there is. JP-A-56-167708 discloses an optically active polymer of acrylic acid amide.This substance exhibits a large optical rotation based on its molecular asymmetry and may be used as an optical resolving agent. Are listed. Further, JP-A-63-
No. 1446 discloses an optically active poly (meth) acrylamide compound, which has an optically active group in a side chain, and an adsorbent for separating a racemic mixture into their enantiomers. Is useful. Japanese Patent Application Laid-Open No. 1-79230 discloses a liquid crystal composition using an optically active synthetic polymer compound. Furthermore, the present inventors have found that a polymer or copolymer of an aromatic isocyanate having an optically active amide group has a stable helical structure even in a solution, and that excellent optical properties can be expected. (See Japanese Patent Application No. 8-280413).

[0003] However, these synthetic polymers each have unique properties, but their application range is naturally narrow. For example, racemic compounds to be separated are limited even if the above-mentioned synthetic polymer compound is applied to an optical resolving agent. Therefore, in order to expand such an application range, it is necessary to increase the types of novel polymer compounds having unique properties.

[0004] Based on such a background, an object of the present invention is to provide a novel polymer compound which can be expected to have excellent optical properties and a method for producing the same.

[0005]

The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have found that a novel optically active aromatic isocyanate having an optically active ester group introduced on an aromatic group. The present inventors have found a polymer or copolymer of the present invention and have completed the present invention.

That is, the present invention provides an optically active aromatic isocyanate having a structural degree represented by the following formula (I) as a main component and having a degree of polymerization of 5 or more and having an optically active ester group in a side chain. It is intended to provide a polymer and a method for producing the polymer.

[0007]

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[Wherein R ¹ is the formula (II)

[0009]

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[0010] (R ² and R ³ represents a monovalent aromatic group or an alkyl group having 1 to 14 carbon atoms of 6 to 14 carbon atoms. However, R ² and
R ³ is a different group, and R ² and R ³ may be combined to form an aliphatic ring. n is a number of 0 or 1 indicating the number of methylene groups. ) Represents an optically active ester group. The present invention also relates to an optically active ester having a degree of polymerization of 5 or more, which is mainly composed of a structural unit represented by the above formula (I) and a structural unit represented by the following formula (VII). It is intended to provide a copolymer of an optically active aromatic isocyanate having a group and an achiral isocyanate, and a method for producing the same.

[0011]

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(In the formula, R ⁴ represents an alkyl group having 1 to 14 carbon atoms or a monovalent aromatic group having 6 to 14 carbon atoms.)

[0013]

Embodiments of the present invention will be described below in detail.

The aromatic isocyanate polymer of the present invention mainly comprises a structural unit represented by the formula (I) in which an optically active ester group represented by the formula (II) is introduced on an aromatic group. Is what you do. In the formula (II) representing an optically active ester group, R ² and R ³ represent a monovalent aromatic group having 6 to 14 carbon atoms or an alkyl group having 1 to 14 carbon atoms. ~ 6 alkyl groups are preferred. However, R ² and R ³ are different groups, and R ² and R ³ may be combined to form an aliphatic ring. The aliphatic ring formed by R ² and R ³ together is preferably a menthyl group.

Particularly preferred groups among the optically active ester groups represented by the formula (II) are groups represented by the following formulas (III) to (VI).

[0016]

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The aromatic isocyanate copolymer of the present invention is represented by the formula (I) in which an optically active ester group represented by the formula (II) is introduced on the above aromatic group. And a structural unit represented by the above formula (VII). In the formula (VII), R ⁴ has 1 to 1 carbon atoms.
4 represents an alkyl group or a monovalent aromatic group having 6 to 14 carbon atoms, preferably a phenyl group, a phenyl group substituted with an alkoxy group having 1 to 6 carbon atoms, an alkyl group having 1 to 6 carbon atoms, A methoxyphenyl group is more preferred.

The aromatic isocyanate polymer mainly comprising the structural unit represented by the formula (I) of the present invention is represented by the following formula (VIII)
Can be produced by anionic polymerization of an optically active aromatic isocyanate represented by the following formula in the presence of a polymerization initiator.

[0019]

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(Wherein, R ¹ has the above-mentioned meaning.)
The structural unit represented by the above formula (I) of the present invention, and the above formula
(VII) The copolymer of an optically active aromatic isocyanate and an achiral isocyanate having a constitutional unit represented by the following formula (VIII) is an optically active aromatic isocyanate represented by the formula (VIII): Anionic polymerization of an achiral isocyanate represented by the following formula (IX) R ⁴ -N = C = O (IX) (wherein R ⁴ has the above-mentioned meaning) in the presence of a polymerization initiator It can be manufactured by doing.

The aromatic isocyanate having an optically active ester group introduced on the aromatic group represented by the formula (VIII) can be produced by a known method. That is, after converting a carboxylic acid monoester synthesized from the corresponding dicarboxylic acid dichloride and the corresponding optically active alcohol into an acyl azide, Curt
Synthesized by ius rearrangement.

[0022] As the polymerization initiator used in the anionic polymerization of the present invention, SrR ⁵ ₂ (R ⁵ represents an organic group. Hereinafter the _{^{same), CaR 5 2, R 5}} K 2, R 5 Na, R 5 Li, ^{R 5 OH, R 5 ONa,} R 5 OL
i, pyridine, NR ⁵ _3, and the like, a lithium compound is preferably represented by the following formula (X), in particular n- butyl lithium, lithium amide of piperidine is preferred.

R ⁵ Li (X) (wherein R ⁵ represents an organic group) The anionic polymerization in the present invention is carried out in a solvent. The solvent may be any solvent as long as it dissolves the monomer and the polymer at least between the low polymers.
Those that inhibit anionic polymerization and optically active polymerization cannot of course be used. Specific examples of the solvent used include benzene, toluene, dioxane, diethyl ether, a hexane-benzene mixture, a hexane-toluene mixture, and tetrahydrofuran. The polymerization temperature in the present invention is -150 ° C to 0 ° C, preferably -120 ° C to -50 ° C.
° C.

The production of the optically active aromatic isocyanate polymer and the copolymer of the optically active aromatic isocyanate and the achiral isocyanate of the present invention is carried out by living polymerization. It is preferable to block the ends with such as.

The optically active aromatic isocyanate polymer having an optically active ester group introduced on the aromatic group of the present invention, and the optically active aromatic isocyanate having an optically active ester group introduced on the aromatic group. The degree of polymerization of the copolymer of the nate and the achiral isocyanate is 5 or more, preferably 20 to 10,000. This polymer is characterized by having a rigid main chain of 1-nylon consisting only of amide bonds and having high optical rotation.

[0026]

EXAMPLES The present invention will be described below in more detail with reference to Synthesis Examples and Examples, but the present invention is not limited to these Examples. In the following Synthesis Examples and Examples, the optical rotation was measured with a Jasco DIP-181 polarimeter.
The molecular weight of the polymer was measured by a light scattering method using Shodex GPC SYSTEM-21 + DAWN DSP-F equipped with Shodex KF-806L and KF-803 GPC columns. CD spectrum is Jasco J-720L
Was measured by ¹ H-NMR spectrum is Varian VXR-500
(500MHz) or Varian Gemini-2000 (400MHz)
Measured in ° C.

Synthesis Example 1 4-[(S) -α-methylbenzyloxycarbonyl] f
Synthesis of phenyl isocyanate

[0028]

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Under nitrogen, anhydrous tetrahydrofuran (TH
F) 21.0 g of terephthalic acid dichloride dissolved in 150 ml
(S) -α-methylbenzyl alcohol
A mixed solution of 11.9 g (0.097 mol) and 8.6 g (0.109 mol) of pyridine was slowly added dropwise with stirring. At this time, the rate of dropping was adjusted to such an extent that reflux did not occur because heat was generated gently. After completion of the dropwise addition, the mixture was refluxed for 1 hour and allowed to cool. There, 0.1N H
An aqueous solution of Cl and 150 ml of saturated saline were added for washing, and the organic phase was dried over anhydrous magnesium sulfate. The solvent was distilled off to obtain a crude product containing dicarboxylic acid and diester. This was dissolved in 200 ml of chloroform, and the insoluble portion (terephthalic acid) was removed by filtration through a glass filter packed with celite. Chloroform was distilled off under reduced pressure, and the residue was recrystallized (benzene: hexane = 1: 3) to remove the diester, and
[(S) -α-methylbenzyloxycarbonyl] benzoic acid was obtained. White solid, yield 14.2 g (50.9% yield).

4-[(S) -α-methylbenzyloxycarbonyl] benzoic acid 10.0 g (37.0 mmol) was added to acetone 150
The solution was cooled to 0 ° C. in an ice-salt bath, and 4.6 g (45.6 mmol) of triethylamine was added. When 4.9 g (45.6 mmol) of ethyl chloroformate was slowly added dropwise so that the internal temperature did not exceed 5 ° C., a white precipitate was deposited. At 0 ° C
After stirring for 1.5 hours, sodium azide 4.2g (65.1mm
ol) in 30 ml of water was added dropwise. After stirring at 0 ° C for 1.5 hours, the mixture was poured into ice water, and the separated oily substance was dissolved in toluene.
The mixture was extracted with 100 ml, the extract was dried over anhydrous magnesium sulfate, and this toluene solution was heated as it was in a 110 ° C. oil bath for 2 hours. After cooling, toluene was distilled off under reduced pressure to obtain a pale yellow liquid, which was distilled under reduced pressure to give 4-[(S) -α-methylbenzyloxycarbonyl] represented by the above formula (XI).
Phenyl isocyanate was obtained. bp 143-145 ° C / 0.
25mmHg, colorless high viscosity liquid, yield 3.4g (34% yield),
[Α] ₃₆₅ ²⁵ = + 377.0 °, [α] _D ²⁵ = + 72.9 ° (c =
0.8, THF).

Synthesis Example 2 3-[(S) -α-methylbenzyloxycarbonyl] f
Synthesis of phenyl isocyanate

[0032]

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In the same manner as in Synthesis Example 1, 3-phthalic acid was obtained from isophthalic acid dichloride and (S) -α-methylbenzyl alcohol.
[(S) -α-methylbenzyloxycarbonyl] benzoic acid was obtained. White solid, yield 11.9 g (40.6% yield).

From the obtained 3-[(S) -α-methylzindyloxycarbonyl] benzoic acid, Curtius rearrangement was carried out in the same manner as in Synthesis Example 1 to give 3- (S) represented by the above formula (XII).
[(S) -α-methylbenzyloxycarbonyl] phenyl isocyanate was obtained at bp 145 ° C./0.3 mmHg, colorless high-viscosity liquid, yield 4.1 g (38% yield), [α] ₃₆₅ ²⁵ = +
222.7 °, [α] _D ²⁵ = + 48 ° (c = 0.8, THF).

Synthesis Example 3 3-[(-)-menthoxycarbonyl] phenyliso
Synthesis of cyanate

[0036]

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In the same manner as in Synthesis Example 1, 3-[(-)-menthoxycarbonyl] benzoic acid was obtained from isophthalic dichloride and (-)-menthol. However, since the crude product did not crystallize, it was purified by silica gel column chromatography (developing solvent: chloroform: hexane = 1: 1 → chloroform only) to remove dicarboxylic acid and diester. White solid, yield 20.5 g (43.3% yield).

From the obtained 3-[(-)-menthyloxycarbonyl] benzoic acid, Curtiu was prepared in the same manner as in Synthesis Example 1.
By the s rearrangement, 3-[(-)-menthoxycarbonyl] phenyl isocyanate represented by the above (XIII) was obtained. bp 144 ° C / 0.3mmHg, colorless high viscosity liquid, yield 2.9
g (yield 29%), [α] ₃₆₅ ²⁵ = -204.2 °, [α] _D
²⁵ = -67.5 ° (c = 0.6, THF).

Synthesis Example 4 3-[(S) -2-methylbutoxycarbonyl ] phenyl
Synthesis of luisocyanate

[0040]

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In the same manner as in Synthesis Example 1, 3-[(S) was prepared from isophthalic dichloride and (S) -2-methylbutanol.
-2-Methylbutoxycarbonyl] benzoic acid was obtained. White solid, yield 21.5 g (40.8% yield).

From the obtained 3-[(S) -2-methylbutoxycarbonyl] benzoic acid, in the same manner as in Synthesis Example 1,
Due to the Curtius rearrangement, the 3-
[(S) -2-Methylbutoxycarbonyl] phenyl isocyanate was obtained. bp 91-94 ° C / 0.25 mmHg, colorless high-viscosity liquid, yield 4.4 g (40% yield), [α] ₃₆₅ ²⁵ = +
14.7 °, (c = 2.6, THF).

Synthesis Example 5 3-[(S) -sec-butoxycarbonyl] phenyl
Synthesis of isocyanates

[0044]

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In the same manner as in Synthesis Example 1, isophthalic dichloride and (S) -sec-butanol were converted to 3-[(S)-
[sec-butoxycarbonyl] benzoic acid. White solid, yield 13.8 g (38.9% yield).

From the obtained 3-[(S) -2-methylbutoxycarbonyl] benzoic acid, in the same manner as in Synthesis Example 1,
3-[(S)-represented by the formula (XV) by the Curtius rearrangement
2-methylbutoxycarbonyl] phenyl isocyanate was obtained. bp90 ℃ / 0.25mmHg, colorless high viscosity liquid, yield
8.6 g (67% yield), [α] ₃₆₅ ²⁵ = + 87.1 °, [α]
_D ²⁵ = + 28.6 ° (c = 0.7, THF).

Synthesis Example 6 (Preparation of polymerization initiator) A mixed solution of 0.10 g (1.2 mmol) of piperidine and 6.0 ml of THF was added at room temperature to a pentane solution of tert-butyllithium (1.71 g).
N) 0.61 ml (1.04 mmol) was added to prepare lithium amide of piperidine.

Example 1 4-[(S) -α-methylbenzyloxycarbonyl] f
Polymerization of phenyl isocyanate Polymerization was carried out in a glass ampoule under a nitrogen atmosphere. A glass ampoule was charged with 0.50 g (1.9 mmol) of 4-[(S) -α-methylbenzyloxycarbonyl] phenyl isocyanate and THF (5 ml), and cooled to -98 ° C.
The polymerization initiator obtained in (1) (lithium amide of piperidine) was added with a 1/50 equivalent syringe of the monomer to start the reaction.
After 0.5 hour, the reaction was stopped with hydrochloric acid-methanol 10 times the amount of the polymerization initiator, and then poured into a large amount of methanol to precipitate, collected by centrifugation, and dried in vacuum at room temperature.
Yield 56%, number average molecular weight (Mn) = 3.1 × 10 ⁴ , molecular weight distribution (Mw / Mn) = 1.5, [α] ₃₆₅ ²⁵ = −1309 ° (TH
F).

Example 2 3-[(S) -α-methylbenzyloxycarbonyl] f
Polymerization of phenyl isocyanate Instead of 4-[(S) -α-methylbenzyloxycarbonyl] phenyl isocyanate, 3-[(S) -α-
[Methylbenzyloxycarbonyl] phenyl isocyanate was used to obtain a polymer in the same manner as in Example 1 except that the polymerization time was changed to 4 hours. Yield 77%, number average molecular weight (M
n) = 3.4 × 10 ⁴ , molecular weight distribution (Mw / Mn) = 1.5,
[Α] ₃₆₅ ²⁵ = -1783 ° (THF).

Example 3 3-[(-)-menthoxycarbonyl] phenyliso
Polymerization of cyanate Instead of 4-[(S) -α-methylbenzyloxycarbonyl] phenyl isocyanate, 3-[(−)-menthoxycarbonyl] phenyl isocyanate is used,
A polymer was obtained in the same manner as in Example 1 except that the polymerization time was changed to 4 hours. Yield 64%, number average molecular weight (Mn) = 2.1 × 10
⁴ , molecular weight distribution (Mw / Mn) = 1.2, [α] ₃₆₅ ²⁵ = -19
24 ° (THF).

Example 4 3-[(S) -2-methylbutoxycarbonyl ] phenyl
Polymerization of luisocyanate Instead of 4-[(S) -α-methylbenzyloxycarbonyl] phenyl isocyanate, 3-[(S) -2-
Methylbutoxycarbonyl] phenyl isocyanate was used to obtain a polymer in the same manner as in Example 1 except that the polymerization time was changed to 4 hours. Yield 40%, number average molecular weight (Mn) =
2.7 × 10 ⁴ , molecular weight distribution (Mw / Mn) = 1.1, [α] ₃₆₅
²⁵ = + 58 ° (THF).

Example 5 3-[(S) -sec-butoxycarbonyl] phenyl
Polymerization of isocyanate Instead of 4-[(S) -α-methylbenzyloxycarbonyl] phenyl isocyanate, 3-[(S) -se
A polymer was obtained in the same manner as in Example 1 except that the polymerization time was changed to 4 hours using [c-butoxycarbonyl] phenyl isocyanate. Yield 51%, number average molecular weight (Mn) = 2.6
× 10 ⁴ , molecular weight distribution (Mw / Mn) = 1.1, [α] ₃₆₅ ²⁵ =
+1272 [deg.] (THF).

The optical rotation of the polymers obtained in Examples 1 to 5 was revealed by a CD spectrum to be mainly derived from a helical structure which was biased in one direction winding of the main chain. FIG. 1 shows CD spectra of the isocyanate polymers obtained in Examples 1 to 5.

Further, the specific rotation of the isocyanate polymer obtained in Example 4 sharply increases at low temperature, and at -78 ° C.
It reached 1465 °. It is considered that this is because in a low temperature state, a one-way spiral structure is formed due to the chirality of the side chain.

More interestingly, the sign of the specific rotation of the isocyanate polymer obtained in Example 5 was reversibly inverted with temperature. The CD absorption pattern of the amide region of the main chain changed to an almost symmetric pattern corresponding to the reversal of the sign of the optical rotation. Therefore, it is considered that reversible helix-helix rearrangement occurs in this polymer depending on temperature. FIG. 2 shows the CD spectra of the isocyanate polymer obtained in Example 5 at 25 ° C. and −45 ° C.

Examples 6 to 12 3-[(S) -α-methylbenzyloxycarbonyl] f
Phenyl isocyanate and m-methoxyphenyl isocyanate
Copolymerization polymerization with inert during glass ampules were run under a nitrogen atmosphere. The 3-[(S) -α-methylbenzyloxycarbonyl] phenyl isocyanate monomer, m-methoxyphenyl isocyanate monomer and tetrahydrofuran obtained in Synthesis Example 2 are placed in a glass ampule, and cooled to -98 ° C. Polymerization initiator obtained in 6 (lithium amide of piperidine)
Was added 50 times the amount of the monomer to start the reaction. Four hours later,
After terminating the reaction with hydrochloric acid-methanol 10 times the amount of the polymerization initiator, the reaction was poured into a large amount of methanol to precipitate, collected by centrifugation, and dried in vacuum at room temperature. The composition of the copolymer was determined by ¹ H-NMR spectrum.

The ratio of the two monomers used, the yield, the copolymer composition, the optical rotation ([α] ₃₆₅ ²⁵ ), the number average molecular weight (Mn),
Table 1 shows the molecular weight distribution (Mw / Mn). FIG. 3 shows a sixth embodiment.
11 shows the relationship between the optical rotation ([α] ₃₆₅ ²⁵ ) and the composition ratio of the copolymers obtained in Nos. 1 to 11.

[0058]

[Table 1]

Note) [A]: 3-[(S) -α-methylbenzyloxycarbonyl] phenyl isocyanate [B]: m-methoxyphenyl isocyanate In the polymers obtained in Examples 7 to 12, The sign of the optical rotation was inverted due to the composition of the coalescence. Since the sign of the absorption in the main chain region in the CD spectrum is also inverted in accordance with the change in the optical rotation, it is considered that the spiral direction is inverted according to the composition ratio.

[Brief description of the drawings]

FIG. 1 is a CD spectrum of the isocyanate polymers obtained in Examples 1 to 5.

FIG. 2 shows a diagram of the isocyanate polymer obtained in Example 5.
It is a CD spectrum at 25 ° C and -45 ° C.

FIG. 3 is a graph showing the relationship between the optical rotation ([α] ₃₆₅ ²⁵ ) and the composition ratio of the copolymers obtained in Examples 6 to 11.

Claims (8)

[Claims] 1. A polymer of an optically active aromatic isocyanate having an optically active ester group in a side chain and mainly comprising a structural unit represented by the following formula (I) and having a degree of polymerization of 5 or more. Embedded image [Wherein R ¹ is a group represented by the formula (II): (R ² and R ³ represents a monovalent aromatic group or an alkyl group having 1 to 14 carbon atoms of 6 to 14 carbon atoms. However, R ² and R ³ are each different group, and R ² and R ³ may be combined to form an aliphatic ring, and n is an optically active ester group represented by the following formula: ] 2. An optically active ester group represented by the following formula (III):
The polymer according to claim 1, which is a group represented by (VI). Embedded image 3. An optically active ester group having a degree of polymerization of 5 or more, which is mainly composed of a structural unit represented by the above formula (I) and a structural unit represented by the following formula (VII), Copolymer of an optically active aromatic isocyanate and an achiral isocyanate. Embedded image (In the formula, R ⁴ is an alkyl group having 1 to 14 carbon atoms or 6 to
It represents 14 monovalent aromatic groups. ) 4. An optically active ester group represented by the formula (III):
The copolymer according to claim 3, which is a group represented by (VI). 5. The process for producing a polymer according to claim 1, wherein an optically active aromatic isocyanate represented by the following formula (VIII) is anionically polymerized in the presence of a polymerization initiator. . Embedded image (Wherein, R ¹ has the meaning described above.) 6. An optically active aromatic isocyanate represented by the above formula (VIII), and a compound represented by the following formula (IX) R ⁴ —NOC ＝ O (IX) (wherein R ⁴ has the same meaning as described above.) 5. The method for producing a copolymer according to claim 3, wherein the achiral isocyanate represented by the formula (1) is anionically polymerized in the presence of a polymerization initiator. 7. The method according to claim 5, wherein the polymerization initiator is a lithium compound represented by the following formula (X). R ⁵ Li (X) (wherein, R ⁵ represents an organic group.) 8. The lithium compound represented by the formula (X) is n
The method according to claim 7, which is lithium amide of -butyllithium or piperidine.