Compound, liquid crystal composition, and liquid crystal display element

Abstract

The present invention provides a compound that sufficiently satisfies at least one of high stability to heat or light, high clearing point (or high upper limit temperature of the nematic phase), low lower limit temperature of the nematic phase, small viscosity, appropriate optical anisotropy, positive or negative and large dielectric anisotropy, appropriate elastic constant, good compatibility with other liquid crystal compounds, and other properties. The compound is represented by formula (1), wherein, for example, R1 and R2 are alkyl groups having 1 to 20 carbon atoms, ring A1 is 1,4-cyclohexylene, 1,4-cyclohexenylene or 1,4-phenylene, Z1 is a single bond, -(CH2)2-, -CH2O- or -OCH2-, and a is 0, 1, 2 or 3.

Description

Compounds, liquid crystal compositions and liquid crystal display elements Technical Field

[0001] This invention relates to a liquid crystal compound, a liquid crystal composition, and a liquid crystal display element. More specifically, it relates to a compound having benzothiophene, a liquid crystal composition containing the compound and having a nematic phase, and a liquid crystal display element containing the composition. Background Technology

[0002] In liquid crystal display elements, classification based on the operating mode of liquid crystal molecules includes phase change (PC), twisted nematic (TN), super twisted nematic (STN), electrically controlled birefringence (ECB), optically compensated bend (OCB), in-plane switching (IPS), vertical alignment (VA), fringe field switching (FFS), and field-induced photo-reactive alignment (FPA). Classification based on the driving method of the element includes passive matrix (PM) and active matrix (AM). PM is further classified into static and multiplex types, while AM ​​is classified into thin-film transistor (TFT) and metal-insulator-metal (MIM) types.

[0003] A liquid crystal composition is encapsulated within the element. The properties of this composition are related to the characteristics of the element. Examples of properties in the composition include thermal or light stability, temperature range of the nematic phase, viscosity, optical anisotropy, dielectric anisotropy, resistivity, and elastic constant. The composition is prepared by mixing many liquid crystal compounds. Desired properties of the liquid crystal compound include high stability to environments such as water, air, heat, and light; a wide temperature range of the liquid crystal phase; low viscosity; suitable optical anisotropy; large dielectric anisotropy; suitable elastic constant; and good compatibility with other liquid crystal compounds. Preferably, the compound has a high upper limit temperature for the nematic phase. As a liquid crystal compound, it is preferable to have a low lower limit temperature in liquid crystal phases such as nematic or smectic phases. Liquid crystal compounds with low viscosity contribute to a short response time of the element. A suitable value for optical anisotropy depends on the type of operating mode of the element. When driving the element with a low voltage, a liquid crystal compound with positive or negative and large dielectric anisotropy is preferred. When preparing liquid crystal compositions, compounds with good compatibility with other liquid crystal compounds are preferred. Since elements are sometimes used at temperatures below freezing, liquid crystal compounds with good compatibility at low temperatures are also preferred.

[0004] To date, several liquid crystal compounds having a benzothiophene skeleton have been synthesized. Compounds (A) and (B), etc., are shown in Patent Documents 1 and 2. However, for these compounds, there is a need to further optimize the type, number, and position of the substituents on the benzothiophene ring to improve their properties.

[0005] [Existing Technical Documents]

[0006] [Patent Literature]

[0007] [Patent Document 1] International Publication No. 2016 / 132998

[0008] [Patent Document 2] International Publication No. 2017 / 064892. Summary of the Invention

[0009] [The technical problem that the invention aims to solve]

[0010] The first technical problem is to provide a liquid crystal compound that satisfies at least one of the following properties: high thermal or optical stability, high clearing point (or high upper limit temperature of the nematic phase), low lower limit temperature of the nematic phase, low viscosity, suitable optical anisotropy, large positive or negative dielectric anisotropy, suitable elastic constant, and good compatibility with other liquid crystal compounds. Compared with similar compounds, a compound having large positive or negative dielectric anisotropy is provided. The second technical problem is to provide a liquid crystal composition containing the compound that satisfies at least one of the following properties: high thermal or optical stability, high upper limit temperature of the nematic phase, low lower limit temperature of the nematic phase, low viscosity, suitable optical anisotropy, large positive or negative dielectric anisotropy, high specific resistivity, and suitable elastic constant. This technical problem is to provide a liquid crystal composition having a suitable balance with respect to at least two of these properties. The third technical problem is to provide a liquid crystal display element comprising the composition, which satisfies at least one of the following characteristics for use: wide temperature range, short response time, high voltage retention rate, low threshold voltage, high contrast ratio, low flicker rate, and long lifespan.

[0011] [Methods for solving technical problems]

[0012] A compound represented by formula (1).

[0013] In equation (1),

[0014] R 1 and R 2 Independently, it is an alkyl group having 1 to 20 carbon atoms, wherein at least one -CH2- can be substituted with -O- or -S-, at least one -(CH2)2- can be substituted with -CH=CH-, and in these groups, at least one hydrogen atom can be substituted with a halogen, wherein R 2 Not methoxy;

[0015] Ring A 1 Independently, it is 1,4-cyclohexene, 1,4-cyclohexenyl, 1,4-phenylene, 1,3-cyclohexadiene-1,4-diyl, tetrahydropyran-2,5-diyl, 1,3-dioxane-2,5-diyl, pyrimidin-2,5-diyl, 2,6,7-trioxabicyclo[2.2.2]octane-1,4-diyl, naphthyl-2,6-diyl, or pyridine-2,5-diyl, wherein at least one hydrogen atom on these rings may be substituted with a halogen;

[0016] Z 1It is independently a single bond or an alkylene group having 1 to 4 carbon atoms, wherein at least one -CH2- can be substituted with -O- or -COO-, at least one -(CH2)2- can be substituted with -CH=CH- or -C≡C-, and at least one hydrogen atom in these groups can be substituted with a halogen;

[0017] a can be 0, 1, 2, or 3.

[0018] [The effects of the invention]

[0019] The first advantage is to provide a liquid crystal compound that satisfies at least one of the following properties: high thermal or optical stability, high clearing point (or high upper limit temperature of the nematic phase), low lower limit temperature of the nematic phase, low viscosity, suitable optical anisotropy, large positive or negative dielectric anisotropy, suitable elastic constant, and good compatibility with other liquid crystal compounds. Compared with similar compounds, a compound with large positive or negative dielectric anisotropy is provided. The second advantage is to provide a liquid crystal composition containing the compound that satisfies at least one of the following properties: high thermal or optical stability, high upper limit temperature of the nematic phase, low lower limit temperature of the nematic phase, low viscosity, suitable optical anisotropy, large positive or negative dielectric anisotropy, high specific resistivity, and suitable elastic constant. This advantage is to provide a liquid crystal composition that has a suitable balance with respect to at least two of these properties. The third advantage is to provide a liquid crystal display element comprising the composition, which fully satisfies at least one of the following characteristics: wide temperature range, short response time, large voltage retention rate, low threshold voltage, large contrast ratio, low flicker rate, and long lifespan. Detailed Implementation

[0020] The usage of terms in this specification is as follows. Sometimes, the terms "liquid crystal compound," "liquid crystal composition," and "liquid crystal display element" are abbreviated as "compound," "composition," and "element," respectively. "Liquid crystal compound" is a general term for compounds having liquid crystal phases such as nematic or lamellar phases, as well as compounds that, although not having a liquid crystal phase, are added to adjust the physical properties of the composition, such as upper and lower temperature limits, viscosity, and dielectric anisotropy. This compound has a six-membered ring, such as 1,4-cyclohexylene or 1,4-phenylene, and its molecular structure is rod-like. "Liquid crystal display element" is a general term for liquid crystal display panels and liquid crystal display modules. "Polymerizable compound" is a compound added for the purpose of forming polymers in the composition. Liquid crystal compounds containing alkenyl groups are not polymerizable in their meaning.

[0021] Liquid crystal compositions are prepared by mixing various liquid crystal compounds. Additives are added to the composition for further adjustment of physical properties. Additives such as polymerizable compounds, polymerization initiators, polymerization inhibitors, optically active compounds, antioxidants, UV absorbers, light stabilizers, heat stabilizers, pigments, and defoamers are added as needed. The liquid crystal compounds or additives are mixed in this order. Even when additives are added, the proportion (content) of the liquid crystal compound is expressed as a weight percentage (wt%) based on the weight of the liquid crystal composition without additives. The proportion (amount) of the additive is expressed as a weight percentage (wt%) based on the weight of the liquid crystal composition without additives. That is, the proportion of the liquid crystal compound or additive is calculated based on the total weight of the liquid crystal compound. Sometimes parts per million (ppm) are also used. The proportions of polymerization initiators and polymerization inhibitors are exceptionally expressed based on the weight of the polymerizable compound.

[0022] "Clearing point" refers to the transition temperature of the liquid crystal phase to the isotropic phase in a liquid crystal compound. "Lower limit temperature of the liquid crystal phase" refers to the transition temperature of the solid to the liquid crystal phase (laminar phase, nematic phase, etc.) in a liquid crystal compound. "Upper limit temperature of the nematic phase" refers to the transition temperature of the nematic phase to the isotropic phase in a mixture of the liquid crystal compound and the parent liquid crystal or in a liquid crystal composition; sometimes simply referred to as the "upper limit temperature." Sometimes, the "lower limit temperature of the nematic phase" is simply referred to as the "lower limit temperature." "Improved dielectric anisotropy" means a positive increase in dielectric anisotropy in a composition with positive dielectric anisotropy, and a negative increase in dielectric anisotropy in a composition with negative dielectric anisotropy. "High voltage retention rate" means that the element has a high voltage retention rate not only at room temperature in the initial stage, but also at temperatures close to the upper limit temperature, and after long-term use, it maintains a high voltage retention rate not only at room temperature but also at temperatures close to the upper limit temperature. In compositions or elements, characteristics are sometimes studied before and after time-varying tests (including accelerated degradation tests).

[0023] Sometimes the compound represented by formula (1) is simply referred to as compound (1). Sometimes at least one compound selected from the group consisting of compounds represented by formula (1) is simply referred to as compound (1). “Compound (1)” means a single compound, a mixture of two compounds, or a mixture of three or more compounds represented by formula (1). These rules also apply to compounds represented by other formulas. In formulas (1) to (15), N enclosed by a hexagon 1 B 1 C 1 The codes correspond to ring N respectively. 1 Ring B 1 , Ring C 1Isocyclic. Hexagons represent six-membered rings such as cyclohexane or benzene. Hexagons sometimes represent condensed rings such as naphthalene or cross-linked rings such as adamantane.

[0024] In the chemical formula of the component compound, the terminal group R 11 The code is used for a variety of compounds. In these compounds, any two R... 11 The two groups represented can be the same or different. For example, there is compound (2) with R 11 It is an ethyl group, and the R of compound (3) is... 11 In the case of an ethyl group. There is also compound (2) with R... 11 It is an ethyl group, and the R of compound (3) is... 11 For propyl. This rule also applies to R. 12 R 13 Z 11 The code is as follows. In compound (24), when i is 2, there are two rings E. 1 In this compound, two rings E 1 The two bases represented can be the same or different. When i is greater than 2, this also applies to any two rings E. 1 This rule also applies to other code.

[0025] The expression "at least one 'A'" means that the number of 'A's is arbitrary. The expression "at least one 'A' can be substituted by 'B'" means that when there is one 'A', the position of 'A' is arbitrary; when there are two or more 'A's, their positions can also be chosen without restriction. This rule also applies to the expression "at least one 'A' is substituted by 'B'". The expression "at least one 'A' can be substituted by 'B', 'C', or 'D'" includes cases where any 'A' is substituted by 'B', any 'A' is substituted by 'C', and any 'A' is substituted by 'D', and further cases where multiple 'A's are substituted by at least two of 'B', 'C', or 'D'. For example, "at least one -CH2- can be substituted by -O- or -CH=CH-" includes alkyl, alkoxy, alkoxyalkyl, alkenyl, alkoxyalkenyl, and alkenoxyalkyl. Furthermore, the case where two consecutive -CH2- are substituted by -O- to become -OO- is undesirable. In alkyl groups, the situation where the -CH2- of the methyl moiety (-CH2-H) is replaced by -O- to become -OH is also undesirable.

[0026] Sometimes use "R" 11 and R 12The expression “independently an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, wherein at least one -CH2- group can be substituted with -O-, and wherein at least one hydrogen atom can be substituted with fluorine”. In this expression, “in these groups” can be interpreted semantically. In this expression, “in these groups” refers to alkyl, alkenyl, alkoxy, alkenyloxy, etc. That is, “in these groups” means all the groups mentioned before the phrase “in these groups”. This common-sense interpretation also applies to the phrases “in these monovalent groups” or “in these divalent groups”. For example, “in these monovalent groups” means all the groups mentioned before the phrase “in these monovalent groups”.

[0027] Halogens refer to fluorine, chlorine, bromine, and iodine. Fluorine and chlorine are preferred halogens, with fluorine being the most desirable. Hydrogen refers to a hydrogen atom. The alkyl groups in liquid crystal compounds are either straight-chain or branched and do not contain cyclic alkyl groups. Straight-chain alkyl groups are generally preferred over branched alkyl groups. The same applies to terminal groups such as alkoxy and alkenyl groups. To increase the upper temperature limit, the stereoconfiguration associated with 1,4-cyclohexylene is trans preferred over cis. 2-Fluoro-1,4-phenylene refers to the two divalent groups described below. In the chemical formula, fluorine can be left-facing (L) or right-facing (R). This rule also applies to asymmetric divalent groups such as tetrahydropyran-2,5-diyl, which are formed by removing two hydrogens from the ring.

[0028] Equation (PN-4) for the ring PN can be in the direction of equation (PN-4-1) or in the direction of equation (PN-4-2). This rule also applies to equation (PN-5).

[0029] The present invention includes the following items, etc.

[0030] [1] A compound represented by formula (1).

[0031] In equation (1),

[0032] R 1 and R 2 Independently, it is an alkyl group having 1 to 20 carbon atoms, wherein at least one -CH2- can be substituted with -O- or -S-, at least one -(CH2)2- can be substituted with -CH=CH-, and in these groups, at least one hydrogen atom can be substituted with a halogen, wherein R 2 Not methoxy;

[0033] Ring A 1Independently, it is 1,4-cyclohexene, 1,4-cyclohexenyl, 1,4-phenylene, 1,3-cyclohexadiene-1,4-diyl, tetrahydropyran-2,5-diyl, 1,3-dioxane-2,5-diyl, pyrimidin-2,5-diyl, 2,6,7-trioxabicyclo[2.2.2]octane-1,4-diyl, naphthyl-2,6-diyl, or pyridine-2,5-diyl, wherein at least one hydrogen atom on these rings may be substituted with a halogen;

[0034] Z 1 It is independently a single bond or an alkylene group having 1 to 4 carbon atoms, wherein at least one -CH2- can be substituted with -O- or -COO-, at least one -(CH2)2- can be substituted with -CH=CH- or -C≡C-, and at least one hydrogen atom in these groups can be substituted with a halogen;

[0035] a can be 0, 1, 2, or 3.

[0036] [2] The compound as described in item [1], wherein, in the formula (1),

[0037] R 1 R is an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an alkyl group having 1 to 10 carbon atoms in which at least one hydrogen atom is substituted with fluorine. 2 It is an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 2 to 9 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an alkyl group having 1 to 10 carbon atoms in which at least one hydrogen atom is replaced by fluorine.

[0038] Ring A 1 Independently 1,4-cyclohexene, 1,4-cyclohexenyl, 1,4-phenylene, 1,4-phenylene with at least one hydrogen substituted by a halogen, or tetrahydropyran-2,5-diyl.

[0039] Z 1 Independently, it can be a single bond, -(CH2)2-, -CH=CH-, -CF=CF-, -C≡C-, -COO-, -OCO-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -(CH2)4-, -(CH2)2CF2O-, -(CH2)2OCF2-, -CF2O(CH2)2-, -OCF2(CH2)2-, -CH=CH-(CH2)2-, or -(CH2)2-CH=CH-;

[0040] a can be 0, 1, 2, or 3.

[0041] [3] The compound described in item [1] is represented by any one of formulas (1-1) to (1-4).

[0042] In equations (1-1) to (1-4),

[0043] R 1 It is an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an alkyl group having 1 to 10 carbon atoms in which at least one hydrogen atom is substituted with fluorine; R 2 It is an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 2 to 9 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an alkyl group having 1 to 10 carbon atoms in which at least one hydrogen atom is replaced by fluorine.

[0044] Ring A 2 Ring A 3 and Ring A 4 Independently 1,4-cyclohexene, 1,4-cyclohexenyl, 1,4-phenylene, 1,4-phenylene with at least one hydrogen substituted by a halogen, or tetrahydropyran-2,5-diyl.

[0045] Z 2 Z 4 and Z 5 Independently, it can be a single bond, -(CH2)2-, -CH=CH-, -CF=CF-, -C≡C-, -COO-, -OCO-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -(CH2)4-, -(CH2)2CF2O-, -(CH2)2OCF2-, -CF2O(CH2)2-, -OCF2(CH2)2-, -CH=CH-(CH2)2-, or -(CH2)2-CH=CH-.

[0046] [4] The compound as described in item [3], wherein, in formulas (1-1) to (1-4),

[0047] R 1 It is an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an alkyl group having 1 to 10 carbon atoms in which at least one hydrogen atom is substituted with fluorine; R 2 It is an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 2 to 9 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an alkyl group having 1 to 10 carbon atoms in which at least one hydrogen atom is replaced by fluorine.

[0048] Ring A 2 Ring A 3 and Ring A 4 Independently 1,4-cyclohexene, 1,4-cyclohexenyl, 1,4-phenylene, 1,4-phenylene with at least one hydrogen substituted by a halogen, or tetrahydropyran-2,5-diyl.

[0049] Z 2 Z 4 and Z 5It can be a single bond, -(CH2)2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, or -OCH2-.

[0050] [5] The compound described in item [4] is represented by any one of formulas (1-1-1) to (1-4-1).

[0051] In equations (1-1-1) to (1-4-1),

[0052] R 1 It is an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an alkyl group having 1 to 10 carbon atoms in which at least one hydrogen atom is substituted with fluorine; R 2 It is an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 2 to 9 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an alkyl group having 1 to 10 carbon atoms in which at least one hydrogen atom is replaced by fluorine.

[0053] Ring A 2 Ring A 3 and Ring A 4 Independently 1,4-cyclohexene, 1,4-cyclohexenyl, 1,4-phenylene, 1,4-phenylene with at least one hydrogen substituted by a halogen, or tetrahydropyran-2,5-diyl.

[0054] [6] A liquid crystal composition comprising at least one of the compounds described in any one of items [1] to [5].

[0055] [7] The liquid crystal composition as described in item [6] contains at least one compound selected from the group consisting of compounds represented by formulas (2) to (4).

[0056] In equations (2) to (4),

[0057] R 11 and R 12 Independently, it is an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, in this R 11 and R 12 In this configuration, at least one -CH2- can be substituted with -O-, and at least one hydrogen can be substituted with fluorine, wherein the hydrogen is not -CF3, -CHF2, -CH2F, -OCF3, -OCHF2, -OCF2CHF2, or -OCF2CHFCF3;

[0058] Ring B 1 Ring B 2 Ring B 3 and Ring B 4It is independently 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,5-difluoro-1,4-phenylene, or pyrimidin-2,5-diyl;

[0059] Z 11 Z 12 and Z 13 It can be a single bond, -COO-, -(CH2)2-, -CH=CH-, or -C≡C- independently.

[0060] [8] The liquid crystal composition as described in item [6] or item [7] further comprises at least one compound selected from the group consisting of compounds represented by formulas (5) to (13).

[0061] In equations (5) to (13),

[0062] R 13 and R 14 Independently, it is an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, in this R 13 and R 14 In this process, at least one -CH2- can be substituted with -O-, and at least one hydrogen atom can be substituted with fluorine.

[0063] R 15 It is hydrogen, fluorine, an alkyl group having 1 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms, in which R 15 In this process, at least one -CH2- can be substituted with -O-, and at least one hydrogen atom can be substituted with fluorine.

[0064] Ring C 1 , Ring C 2 , Ring C 3 and ring C 4 Independently 1,4-cyclohexene, 1,4-cyclohexenyl, 1,4-phenylene whose at least one hydrogen atom can be fluorinated, tetrahydropyran-2,5-diyl or decahydronaphthalene-2,6-diyl;

[0065] Ring C 5 and ring C 6 It is independently 1,4-cyclohexene, 1,4-cyclohexenyl, 1,4-phenylene, tetrahydropyran-2,5-diyl or decahydronaphthalene-2,6-diyl;

[0066] Z 14 Z 15 Z 16 and Z 17 Independently, it can be a single bond, -COO-, -CH2O-, -OCF2-, -(CH2)2-, or -OCF2-(CH2)2-;

[0067] L 11and L 12 Independently fluorine or chlorine;

[0068] S 11 It can be hydrogen or methyl;

[0069] X is -O-, -S-, -CH2-, -CHF-, -CF2-, -CH2CH2-, -CHFCH2-, -CH2CHF-, -CF2CH2-, -CH2CF2-, -CF2CHF-, -CHFCF2-, -CF2CF2-, -CH=CH-, -CF=CH-, -CH=CF- or -CF=CF-;

[0070] j, k, m, n, p, q, r, and s are independently 0 or 1, the sum of k, m, n, and p is 1 or 2, the sum of q, r, and s is 0, 1, 2, or 3, and t and h are independently 1, 2, or 3.

[0071] [9] The liquid crystal composition as described in item [6] or item [7] further comprises at least one compound selected from the group consisting of compounds represented by formulas (21) to (23).

[0072] In equations (21) to (23),

[0073] R 16 It is an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, in which R 16 In this process, at least one -CH2- can be substituted with -O-, and at least one hydrogen atom can be substituted with fluorine.

[0074] X 11 It can be fluorine, chlorine, -CF3, -CHF2, -CH2F, -OCF3, -OCHF2, -OCF2CHF2 or -OCF2CHFCF3;

[0075] Ring D 1 Ring D 2 and ring D 3 Independently 1,4-cyclohexylene, 1,4-phenylene whose at least one hydrogen atom may be fluorinated, tetrahydropyran-2,5-diyl, 1,3-dioxane-2,5-diyl or pyrimidin-2,5-diyl;

[0076] Z 18 Z 19 and Z 20 Independently, it can be a single bond, -COO-, -CH2O-, -CF2O-, -OCF2-, -(CH2)2-, -CH=CH-, -C≡C-, or -(CH2)4-;

[0077] L 13 and L 14It can be either hydrogen or fluorine.

[0078]

[0010] The liquid crystal composition as described in item [6] or item [7] further comprises at least one compound selected from the group consisting of compounds represented by formula (24).

[0079] In equation (24),

[0080] R 17 It is an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, in which R 17 In this process, at least one -CH2- can be substituted with -O-, and at least one hydrogen atom can be substituted with fluorine.

[0081] X 12 It can be -C≡N or -C≡CC≡N;

[0082] Ring E 1 It is 1,4-cyclohexylene, 1,4-phenylene whose at least one hydrogen can be substituted by fluorine, tetrahydropyran-2,5-diyl, 1,3-dioxane-2,5-diyl or pyrimidine-2,5-diyl;

[0083] Z 21 It can be a single bond, -COO-, -CH2O-, -CF2O-, -OCF2-, -(CH2)2-, or -C≡C-;

[0084] L 15 and L 16 Independently hydrogen or fluorine;

[0085] i can be 1, 2, 3 or 4.

[0086]

[0011] A liquid crystal display element comprising a liquid crystal composition as described in any one of [6] to

[0010] .

[0087] The present invention also includes the following: (a) the composition further comprising at least one optically active compound or polymerizable compound. (b) the composition further comprising at least one antioxidant or ultraviolet absorber.

[0088] The present invention also includes the following: (c) The composition further comprises at least one additive selected from the group consisting of polymerizable compounds, polymerization initiators, polymerization inhibitors, optically active compounds, antioxidants, ultraviolet absorbers, light stabilizers, heat stabilizers, pigments, and defoamers. (d) The composition has an upper limit temperature of 70°C or higher for its nematic phase, an optical anisotropy (measured at 25°C) of 0.08 or higher at a wavelength of 589 nm, and a dielectric anisotropy (measured at 25°C) of -2 or less at a frequency of 1 kHz.

[0089] The present invention also includes the following: (e) an element comprising the composition and having a PC, TN, STN, ECB, OCB, IPS, VA, FFS, FPA, or polymer-stable alignment (PSA) mode. (f) an AM element comprising the composition. (g) a transmissive element comprising the composition. (h) use of the composition as a composition having a nematic phase. (i) use of the composition as an optically active composition by adding an optically active compound.

[0090] The state of compound (1), the synthesis of compound (1), the liquid crystal composition and the liquid crystal display element are described in turn.

[0091] 1. The state of compound (1)

[0092] Compound (1) of the present invention will be described. Preferred examples of terminal groups, ring structures, bonding groups, etc. in compound (1) and the effects of these groups on physical properties also apply to the lower form of compound (1).

[0093] This compound is extremely stable in terms of physical and chemical properties under normal operating conditions and exhibits good compatibility with other liquid crystal compounds. Compositions containing this compound are stable under normal operating conditions. This compound possesses the general physical properties and suitable optical anisotropy required for the components of the composition.

[0094] In equation (1),

[0095] R 1 and R 2 Independently, it is an alkyl group having 1 to 20 carbon atoms, wherein at least one -CH2- can be substituted with -O- or -S-, at least one -(CH2)2- can be substituted with -CH=CH-, and in these groups, at least one hydrogen atom can be substituted with a halogen, wherein R 2 It is not methoxyl.

[0096] R 1 Or R 2 Preferred examples are alkyl, alkoxy, alkenyl, and alkenyloxy groups. 1 Further good examples are alkyl and alkenyl groups. R 2 Further preferred examples are alkyl, alkoxy, and alkenyl groups. R 1 Or R 2 It may be an alkoxyalkyl group, an alkyl group in which at least one hydrogen atom is substituted by a halogen, an alkoxy group in which at least one hydrogen atom is substituted by a halogen, or an alkenyl group in which at least one hydrogen atom is substituted by a halogen.

[0097] Examples of alkyl groups are -CH3, -C2H5, -C3H7, -C4H9, and -C5H. 11 -C6H 13 -C7H 15 -C8H 17 -C9H 19 -C 10 H 21 -C 11 H 23 -C 12 H 25 -C 13 H 27 -C 14 H 29 and -C 15 H 31 .

[0098] Examples of alkoxy groups are -OC2H5, -OC3H7, -OC4H9, and -OC5H. 11 -OC6H 13 -OC7H 15 -OC8H 17 -OC9H 19 -OC 10 H 21 -OC 11 H 23 -OC 12 H 25 -OC 13 H 27 and -OC 14 H 29 .

[0099] Examples of alkoxyalkyl groups are -CH2OCH3, -CH2OC2H5, -CH2OC3H7, -(CH2)2-OCH3, -(CH2)2-OC2H5, -(CH2)2-OC3H7, -(CH2)3-OCH3, -(CH2)4-OCH3 and -(CH2)5-OCH3.

[0100] Examples of alkenyl groups are -CH=CH2, -CH=CHCH3, -CH2CH=CH2, -CH=CHC2H5, -CH2CH=CHCH3, -(CH2)2-CH=CH2, -CH=CHC3H7, -CH2CH=CHC2H5, -(CH2)2-CH=CHCH3 and -(CH2)3-CH=CH2.

[0101] Examples of olefinic groups are -OCH2CH=CH2, -OCH2CH=CHCH3 and -OCH2CH=CHC2H5.

[0102] Examples of alkyl groups in which at least one hydrogen atom is substituted by a halogen include -CH2F, -CHF2, -CF3, -(CH2)2-F, -CF2CH3, -CF2CH2F, -CF2CHF2, -CH2CF3, -CF2CF3, -(CH2)3-F, -CF2CH2CH3, -CH2CHFCH3, -CH2CF2CH3, -(CF2)3-F, -CF2CHFCF3, -CHFCF2CF3, -(CH2)4-F, -CF2(CH2)2CH3, -(CF2)4-F, -(CH2)5-F, -(CF2 )5-F, -CH2Cl, -CHCl2, -CCl3, -(CH2)2-Cl, -CCl2CH3, -CCl2CH2Cl, -CCl2CHCl2, -CH2CCl3, -CCl2CCl3, -(CH2)3-Cl, -CCl2CH2 CH3, -(CCl2)3-Cl, -CCl2CHClCCl3, -CHClCCl2CCl3, -(CH2)4-Cl, -(CCl2)4-Cl, -CCl2(CH2)2CH3, -(CH2)5-Cl and -(CCl2)5-Cl.

[0103] Examples of alkoxy groups in which at least one hydrogen atom is substituted by a halogen are -O-(CH2)2-F, -OCF2CH2F, -OCF2CHF2, -OCH2CF3, -O-(CH2)3-F, -O-(CF2)3-F, -OCF2CHFCF3, -OCHFCF2CF3, -O(CH2)4-F, -O-(CF2)4-F, -O-(CH2)5-F, -O-(CF2)5-F, -OCH2CHFCH2CH3, -OCH2 Cl, -OCHCl2, -OCCl3, -O-(CH2)2-Cl, -OCCl2CH2Cl, -OCCl2CHCl2, -OCH2CCl3, -O-(CH2)3-Cl, -O-(CCl2) 3-Cl, -OCCl2CHClCCl3, -OCHClCCl2CCl3, -O(CH2)4-Cl, -O-(CCl2)4-Cl, -O-(CH2)5-Cl and -O-(CCl2)5-Cl.

[0104] Examples of alkenyl groups in which at least one hydrogen atom is substituted by a halogen are -CH=CHF, -CH=CF2, -CF=CHF, -CH=CHCH2F, -CH=CHCF3, -(CH2)2-CH=CF2, -CH2CH=CHCF3, -CH=CHCF2CF3, -CH=CHCl, -CH=CCl2, -CCl=CHCl, -CH=CHCH2Cl, -CH=CHCCl3, -(CH2)2-CH=CCl2, -CH2CH=CHCCl3 and -CH=CHCCl2CCl3.

[0105] In R 2 When the methoxy group is used, the compatibility with other liquid crystal compounds deteriorates significantly, resulting in poor performance.

[0106] In equation (1), ring A 1 Independently, it is 1,4-cyclohexene, 1,4-cyclohexenyl, 1,4-phenylene, 1,3-cyclohexadiene-1,4-diyl, tetrahydropyran-2,5-diyl, 1,3-dioxane-2,5-diyl, pyrimidin-2,5-diyl, 2,6,7-trioxabicyclo[2.2.2]octane-1,4-diyl, naphthalene-2,6-diyl, or pyridine-2,5-diyl, wherein at least one hydrogen atom on these rings may be substituted with a halogen.

[0107] Ring A 1 Preferred examples are 1,4-cyclohexene, 1,4-cyclohexenyl, 1,4-phenylene, 1,4-phenylene with at least one hydrogen substituted by fluorine, tetrahydropyran-2,5-diyl, and 5,5,6,6-tetrafluoro-1,3-cyclohexadiene-1,4-diyl. More preferred examples are 1,4-cyclohexene, 1,4-phenylene, 1,4-phenylene with at least one hydrogen substituted by fluorine, and tetrahydropyran-2,5-diyl. Both cis and trans stereoconfigurations exist in the 1,4-cyclohexene. From the viewpoint of higher upper temperature limits, the trans configuration is preferred.

[0108] Preferred examples of 1,4-phenylene compounds in which at least one hydrogen atom is substituted with a halogen are those represented by formulas (A-1) to (A-17). For having negative and large dielectric anisotropy, it is more preferably represented by formulas (A-1), (A-5), (A-6), (A-7), (A-8), (A-9), (A-10), or (A-11).

[0109] In equation (1), Z 1It is independently a single bond or an alkylene group having 1 to 4 carbon atoms, wherein at least one -CH2- can be substituted with -O- or -COO-, at least one -(CH2)2- can be substituted with -CH=CH- or -C≡C-, and at least one hydrogen atom in these groups can be substituted with a halogen.

[0110] Z 1 Preferred examples are single bonds, -(CH2)2-, -CH=CH-, -CF=CF-, -C≡C-, -COO-, -OCO-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -(CH2)4-, -(CH2)2CF2O-, -(CH2)2OCF2-, -CF2O(CH2)2-, -OCF2(CH2)2-, -CH=CH-(CH2)2-, and -(CH2)2-CH=CH-. More preferred examples are single bonds, -(CH2)2-, -CH=CH-, -COO-, -OCO-, -CF2O-, -OCF2-, -CH2O-, and -OCH2-. Even more preferred examples are single bonds, -(CH2)2-, -CH2O-, and -OCH2-.

[0111] In equation (1), a is 0, 1, 2, or 3. When considering compatibility with other liquid crystal compounds, compounds with a value of 2 or less are preferred. When a is 1 or 0, the viscosity is low. When a is 2, the balance between viscosity and upper limit temperature is excellent. When a is 3, the upper limit temperature is high.

[0112] Compound (1) exhibits high properties due to its benzothiophene skeleton, which has fluorine bonds at the 7 and 5 positions, oxygen bonds at the 6 position, and cyclic or alkyl bonds at the 2 position. The effects of this application cannot be fully achieved with skeletons having different substitution positions for these groups or skeletons with added or removed substituents. This structure results in a high clearing point, a low lower limit temperature of the liquid crystal phase, low viscosity, suitable optical anisotropy, large positive or negative dielectric anisotropy, suitable elastic constant, and excellent compatibility with other liquid crystal compounds.

[0113] As described above, by appropriately selecting the types of terminal groups, ring structures, and bonding groups, compounds with the target properties can be obtained. Since the physical properties of the compounds do not differ significantly, compound (1) can contain a greater amount than the natural abundance. 2 H (deuterium) 13 C isotopes.

[0114] By appropriately selecting the terminal group, ring, and bonding group of compound (1), physical properties such as optical anisotropy and dielectric anisotropy can be arbitrarily adjusted. The following explains the terminal group R. 1 and terminal group R 2, bonding group Z 1 The effect of the type of compound (1) on its physical properties.

[0115] In compound (1), when R 1 Or R 2 When the liquid crystal phase is linear, it has a wide temperature range and low viscosity. When R... 1 Or R 2 When it is a branched chain, it exhibits good compatibility with other liquid crystal compounds. R 1 Or R 2 Compounds with optically active groups are useful as chiral dopants. By adding such compounds to the composition, reverse twisted domains can be prevented from forming in the device. 1 Or R 2 Compounds that are not optically active groups are useful as components of a composition. When R 1 Or R 2 When the compound is alkenyl, the preferred stereoconfiguration depends on the position of the double bond. Alkenyl compounds with preferred stereoconfigurations have high upper temperature limits or wide temperature ranges for liquid crystal phases. These are explained in detail in "Molecular Crystals and Liquid Crystals" (1985, 131, 109) and "Molecular Crystals and Liquid Crystals" (1985, 131, 327).

[0116] In ring A 1 When the molecule is 1,4-phenylene, 1,4-phenylene with at least one hydrogen atom substituted by fluorine or chlorine, naphth-2,6-diyl, pyridin-2,5-diyl, or pyrimidine-2,5-diyl, the optical anisotropy is large. In ring A... 1 When the form is 1,4-cyclohexene, 1,4-cyclohexenyl, tetrahydropyran-2,5-diyl, dihydropyran-2,5-diyl, or 1,3-dioxane-2,5-diyl, the optical anisotropy is small.

[0117] When multiple rings A 1 When the cyclohexene group is 1,4-cyclohexene, the upper limit temperature is high, the optical anisotropy is small, and the viscosity is low. When at least two groups are 1,4-phenylene, the optical anisotropy is large, the temperature range of the liquid crystal phase is wide, and the upper limit temperature is high. When ring A... 1 When at least one of them is 1,4-phenylene, the optical anisotropy is relatively large, and the orientational order parameter is large.

[0118] When Z 1When the bond is a single bond, -CH2O-, -CF2O-, -OCF2-, -(CH2)2-, -CH=CH-, -CF=CF-, or -(CH2)4-, the viscosity is low. When Z 1 When the bond is a single bond, -OCF2-, -CF2O-, -(CH2)2-, or -CH=CH-, the viscosity is lower. When Z 1 When -CH=CH-, the liquid crystal phase has a wide temperature range and its elastic constant is greater than that of K. 33 / K 11 (K 33 : Bending elastic constant, K 11 (The elastic constant of the development is large). When Z 1 When -C≡C-, the optical anisotropy is large.

[0119] When compound (1) has one or two rings, it exhibits good compatibility with other liquid crystal compounds and has low viscosity. When compound (1) has three or four rings, it has a high upper temperature limit. When compound (1) has four rings, it has a wide temperature range for the liquid crystal phase. Here, a polycyclic structure, such as a benzothiophene ring, is also considered as a single ring. As described above, by appropriately selecting the type and number of terminal groups, rings, and bonding groups, compounds with desired physical properties can be obtained. Therefore, compound (1) is useful as a component of compositions used in elements having modes such as PC, TN, STN, ECB, OCB, IPS, and VA.

[0120] Preferred examples of compound (1) are compounds (1-1) to (1-4) as described in item 3. Further preferred examples are compounds (1-1-1) to (1-4-1) as described in item 5. Compound (1) is suitable for elements having modes such as VA, IPS, and PSA.

[0121] 2. Synthesis of compound (1)

[0122] The synthesis of compound (1) will be described. Compound (1) can be synthesized by appropriately combining methods of organic synthetic chemistry. Methods for introducing the desired terminal groups, rings and bonding groups into the starting material are described in books such as *Organic Syntheses* (John Wiley & Sons, Inc.), *Organic Reactions* (John Wiley & Sons, Inc.), *Comprehensive Organic Synthesis* (Pergamon Press), and *New Lectures on Experimental Chemistry* (Maruzen).

[0123] 2-1. Formation of bonding group Z

[0124] Regarding the formation of bonding groups Z 1 The method is described first, showing the process flow. Next, the reactions described in the process flow are explained using (1) to (11). In this process, MSG... 1 (or MSG) 2 () is a monovalent organic group having at least one ring. Multiple MSGs used in the process 1 (or MSG) 2 The monovalent organic groups represented by () may be the same or different. Compounds (1A) to (1J) are equivalent to compound (1).

[0125] (1) Formation of single bonds

[0126] Compound (1A) is synthesized by reacting arylboronic acid (31) synthesized by known methods with a halide (32) in the presence of a catalyst such as carbonate and tetra(triphenylphosphine)palladium. Compound (1A) can also be synthesized by reacting n-butyllithium with a halide (33) synthesized by known methods, followed by reacting zinc chloride, and then reacting the halide (32) in the presence of a catalyst such as dichlorobis(triphenylphosphine)palladium.

[0127] (2) Generation of -COO-

[0128] The carboxylic acid (34) is obtained by reacting n-butyllithium with a halide (33) and then with carbon dioxide. Compound (1B) is synthesized by dehydrating a compound (35) synthesized by a known method with the carboxylic acid (34) in the presence of 1,3-dicyclohexyl carbodiimide (DCC) and 4-dimethyl amino pyridine (DMAP).

[0129] (3) Generation of CF2O-

[0130] Thionoester (36) was obtained by treating compound (1B) with a sulfiding agent such as Lawstson's reagent. Compound (1C) was synthesized by fluorination of thioester (36) with a pyridine hydrofluoride complex and N-bromosuccinimide (NBS). See M. Kuroboshi et al., *Chem. Lett.* (1992, 827). Compound (1C) can also be synthesized by fluorination of thioester (36) with (diethyl amino)sulfur trifluoride (DAST). See WH. Bunnelle et al., *Journal of Organic Chemistry* (1990, 55, 768). The bonding group can also be generated by the method described in Peer. Kirsch et al.'s "Angew. Chem. Int. Ed." (2001, 40, 1480).

[0131] (4) Formation of -CH=CH-

[0132] After treating the halide (32) with n-butyllithium, it was reacted with N,N-dimethylformamide (DMF) to obtain the aldehyde (38). A phosphorus ylide was generated by treating a phosphonium salt (37) synthesized by known methods with a base such as potassium tert-butoxide. This phosphorus ylide was then reacted with the aldehyde (38) to synthesize compound (1D). The cis-iso was generated under the reaction conditions, and therefore, the cis-iso was isomerized to the trans-iso as needed using known methods.

[0133] (5) Generation of (CH2)2-

[0134] Compound (1E) is synthesized by hydrogenating compound (1D) in the presence of a catalyst such as palladium on carbon.

[0135] (6)-(CH2)4- formation

[0136] Using phosphonium salt (39) instead of phosphonium salt (37), a compound having the form -(CH2)2-CH=CH- was obtained according to method (4). This compound was then catalytically hydrogenated to synthesize compound (1F).

[0137] (7) Formation of -CH2CH=CHCH2-

[0138] Phosphorus salt (40) is used instead of phosphorus salt (37), and aldehyde (41) is used instead of aldehyde (38). The compound (1G) is synthesized according to method (4). The trans isomer is generated by the reaction conditions, and the trans isomer isomer isomerized to the cis isomer by known methods as needed.

[0139] (8) Generation of -C≡C-

[0140] Compound (42) was obtained by reacting halide (33) with 2-methyl-3-butyn-2-ol under alkaline conditions in the presence of palladium dichloro and copper halide catalysts. Compound (1H) was synthesized by reacting compound (42) with halide (32) in the presence of palladium dichloro and copper halide catalysts.

[0141] (9) Generation of -CF=CF-

[0142] Compound (43) was obtained by treating halide (33) with n-butyllithium and then reacting it with tetrafluoroethylene. Compound (1I) was synthesized by treating halide (32) with n-butyllithium and then reacting it with compound (43).

[0143] (10) Generation of -OCH2-

[0144] The aldehyde (38) was reduced by a reducing agent such as sodium borohydride to obtain compound (44). The compound (44) was brominated by hydrobromic acid to obtain bromide (45). Compound (1J) was synthesized by reacting bromide (45) with compound (46) in the presence of a base such as potassium carbonate.

[0145] Generation of (11)-(CF2)2-

[0146] According to the method described in the Journal of the American Chemical Society (J. Am. Chem. Soc.) (2001, 123, 5414.), diketones (-COCO-) are fluorinated with sulfur tetrafluoride in the presence of a hydrogen fluoride catalyst to obtain compounds with -(CF2)2-.

[0147] Examples of methods for synthesizing compound (1) are described below. In these compounds, R 1 R 2 Ring A 1 Z 1The definition of a is the same as that in item 1. Compound (b-1), synthesized by known methods, is lithlated using sec-butyllithium (sec-BuLi), and then reacted with sulfur and bromoacetaldehyde diethyl acetal to obtain compound (b-2). Compound (b-3) is obtained by reacting it with polyphosphoric acid in toluene or chlorobenzene. Compound (b-4) is prepared by lithiation of compound (b-3) with lithium diisopropylamide (LDA), and various intermediates are obtained by reacting it with various reagents. Compound (1) is derived using these intermediates and by known methods.

[0148] 3. Liquid crystal composition

[0149] 3-1. Component compounds

[0150] The liquid crystal composition of the present invention will be described. The composition contains at least one compound (1) as component (a). The composition may also contain two or more compounds (1). The composition may consist solely of compound (1). For good physical properties, it is preferable that the composition contains at least one compound (1) in the range of 1% to 99% by weight. In compositions with negative dielectric anisotropy, the preferred content of compound (1) is in the range of 5% to 60% by weight. In compositions with positive dielectric anisotropy, the preferred content of compound (1) is 30% by weight or less.

[0151] Table 1. Components of the composition

[0152] The composition preferably further contains a liquid crystal compound selected from components (b) to (e) shown in Table 1. When preparing the composition, components (b) to (e) are preferably selected taking into account the sign and magnitude of the dielectric anisotropy. The composition may contain a liquid crystal compound different from compounds (1) to (13) and compounds (21) to (24). The composition may also not contain such a liquid crystal compound.

[0153] Component (b) is a compound with two terminal groups being alkyl groups, etc. Preferred examples of component (b) include compounds (2-1) to (2-11), compounds (3-1) to (3-21), and compounds (4-1) to (4-7). In these compounds, R... 11 and R 12 Independently, it is an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, in this R 11 Or R12 In this, at least one -CH2- can be substituted with -O-, and at least one hydrogen can be substituted with fluorine, wherein -CF3, -CHF2, -CH2F, -OCF3, -OCHF2, -OCF2CHF2 or -OCF2CHFCF3 are not included.

[0154] Component (b) exhibits low dielectric anisotropy. Component (b) is nearly neutral. Compound (2) has the effect of reducing viscosity or adjusting optical anisotropy. Compounds (3) and (4) have the effect of expanding the temperature range of the nematic phase or adjusting optical anisotropy by increasing the upper limit temperature.

[0155] As the content of component (b) increases, although the viscosity of the composition decreases, the dielectric anisotropy also decreases. Therefore, a higher content is preferable as long as the critical voltage requirement of the device is met. In the case of preparing compositions for IPS, VA, and other modes, the content of component (b) is preferably 30% by weight or more, and more preferably 40% by weight or more, based on the weight of the liquid crystal composition.

[0156] Component (c) comprises compounds (5) to (13). These compounds, like 2,3-difluoro-1,4-phenylene, have phenylenes with two halogens substituted at the lateral positions. Preferred examples of component (c) include: compounds (5-1) to (5-10), compounds (6-1) to (6-23), compounds (7-1) and (7-2), compounds (8-1) to (8-3), compounds (9-1) to (9-3), compounds (10-1) to (10-11), compounds (11-1) to (11-13), compounds (12-1) to (12-3), and compound (13-1). In these compounds, R 13 and R 14 Independently, it is an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, in this R 13 Or R 14 In this context, at least one -CH2- can be substituted with -O-, at least one hydrogen can be substituted with fluorine, and R 15 It is hydrogen, fluorine, an alkyl group having 1 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms, in which R 15 In this process, at least one -CH2- can be substituted with -O-, and at least one hydrogen can be substituted with fluorine.

[0157] Component (c) exhibits a large and negative dielectric anisotropy. Component (c) can be used in the preparation of compositions for modes such as IPS, VA, and PSA. While the negative dielectric anisotropy of the composition increases with increasing component (c) content, the viscosity also increases. Therefore, a low content is preferable as long as the critical voltage requirement of the device is met. Considering a dielectric anisotropy of approximately -5, a content of 40% by weight or more is preferred for sufficient voltage drive.

[0158] Compound (5) in component (c) is a bicyclic compound, thus having the effect of reducing viscosity, adjusting optical anisotropy, or improving dielectric anisotropy. Compounds (6) and (7) are tricyclic compounds, and compound (8) is a tetracyclic compound, thus having the effect of increasing the upper temperature limit, improving optical anisotropy, or improving dielectric anisotropy. Compounds (9) to (13) have the effect of improving dielectric anisotropy.

[0159] When preparing compositions for IPS, VA, PSA, and other modes, the content of component (c) is preferably in the range of 1% to 99% by weight, based on the weight of the liquid crystal composition. When component (c) is added to a composition with positive dielectric anisotropy, the content of component (c) is preferably 30% by weight or less. By adding component (c), the elastic constant of the composition can be adjusted, and the voltage-transmittance profile of the element can be adjusted.

[0160] Component (d) is compounds (21) to (23), and is a compound having a halogenated or fluorine-containing group at the right end. Preferred examples of component (d) include: compounds (21-1) to (21-16), compounds (22-1) to (22-116), and compounds (23-1) to (23-59). In these compounds, R... 16 It is an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, in which R 16 In this configuration, at least one -CH2- can be substituted with -O-, and at least one hydrogen atom can be substituted with fluorine. X 11 It can be fluorine, chlorine, -CF3, -CHF2, -CH2F, -OCF3, -OCHF2, -OCF2CHF2 or -OCF2CHFCF3.

[0161] Component (d) exhibits positive dielectric anisotropy and excellent thermal and optical stability, making it suitable for use in compositions for IPS, FFS, and OCB modes. The content of component (d) is preferably in the range of 1% to 99% by weight, more preferably 10% to 97% by weight, and even more preferably 40% to 95% by weight, depending on the weight of the liquid crystal composition. When component (d) is added to a composition with negative dielectric anisotropy, its content is preferably 30% by weight or less. By adding component (d), the elastic constant of the composition can be adjusted, and the voltage-transmittance profile of the element can be modified.

[0162] Component (e) is a compound (24) with a right-terminal group of -C≡N or -C≡CC≡N. Preferred examples of component (e) include compounds (24-1) to (24-64). In these compounds, R... 17 It is an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, in which R 17 In this configuration, at least one -CH2- can be substituted with -O-, and at least one hydrogen atom can be substituted with fluorine. X 12 It can be -C≡N or -C≡CC≡N.

[0163] Component (e) has a positive and high dielectric anisotropy, making it suitable for preparing compositions for TN and other modes. Adding component (e) improves the dielectric anisotropy of the composition. Component (e) also has the effect of expanding the temperature range of the liquid crystal phase, adjusting viscosity, or adjusting optical anisotropy. Component (e) is also useful for adjusting the voltage-transmittance profile of the element.

[0164] When preparing compositions for TN and other modes, the content of component (e) is preferably in the range of 1% to 99% by weight, more preferably in the range of 10% to 97% by weight, and even more preferably in the range of 40% to 95% by weight, based on the weight of the liquid crystal composition. When component (e) is added to a composition with negative dielectric anisotropy, the content of component (e) is preferably 30% by weight or less. By adding component (e), the elastic constant of the composition can be adjusted, and the voltage-transmittance curve of the element can be adjusted.

[0165] By combining compounds appropriately selected from components (b) to (e) with compound (1), a liquid crystal composition can be prepared that satisfies at least one of the following properties: high thermal or optical stability, high upper temperature limit, low lower temperature limit, low viscosity, suitable optical anisotropy (i.e., large or small optical anisotropy), positive or negative and large dielectric anisotropy, large specific resistivity, and suitable elastic constant (i.e., large or small elastic constant). Components containing such compositions have a wide usable temperature range, short response time, high voltage retention rate, low critical voltage, high contrast ratio, low flicker rate, and long lifetime.

[0166] If the component is used for a long time, flicker may sometimes occur in the display screen. The flicker rate (%) can be expressed as (|brightness when a positive voltage is applied - brightness when a negative voltage is applied| / average brightness) × 100. Even with prolonged use, components with a flicker rate in the range of 0% to 1% are unlikely to produce flicker in the display screen. It is inferred that this flicker is related to image afterimage and is generated by the potential difference between positive and negative frames when driven by AC. Compositions containing compound (1) are also useful for reducing flicker.

[0167] 3-2. Additives

[0168] Liquid crystal compositions are prepared by known methods. For example, component compounds are mixed and dissolved together by heating. Additives may also be added to the composition depending on the intended use. Examples of additives include polymerizable compounds, polymerization initiators, polymerization inhibitors, optically active compounds, antioxidants, ultraviolet absorbers, light stabilizers, heat stabilizers, pigments, defoamers, etc. Such additives are well known to those skilled in the art and are described in the literature.

[0169] In liquid crystal display elements with PSA (polymer sustained alignment) mode, the composition contains a polymer. The polymerizable compound is added to generate the polymer in the composition. The polymerizable compound is polymerized by irradiating with ultraviolet light while a voltage is applied between the electrodes, thereby generating the polymer in the composition. This method allows for achieving a suitable pretilt, thus enabling the fabrication of elements with shortened response times and improved image retention.

[0170] Preferred examples of polymerizable compounds are acrylates, methacrylates, vinyl compounds, ethylene-oxygenated compounds, propylene ethers, epoxy compounds (oxetane, oxetane), and vinyl ketones. Further preferred examples are compounds having at least one acryloyloxy group and compounds having at least one methacryloyloxy group. Further preferred examples also include compounds having both acryloyloxy and methacryloyloxy groups.

[0171] Better examples are compounds (M-1) to (M-18). In these compounds, R 25 To R 31 Independently hydrogen or methyl; R 32 R 33 and R 34 Independently, it is a hydrogen or an alkyl group having 1 to 5 carbon atoms; v, w, and x are independently 0 or 1; u and y are independently integers from 1 to 10. L 21 To L 26 Independently hydrogen or fluorine; L 27 and L 28 It can be hydrogen, fluorine, or methyl independently.

[0172] Polymerizable compounds can be rapidly polymerized by adding polymerization initiators. The amount of residual polymerizable compound can be reduced by optimizing reaction conditions. Examples of photoradical polymerization initiators include TPO, 1173, and 4265 from BASF's Darocur series (Darocur is a registered trademark), and 184, 369, 500, 651, 784, 819, 907, 1300, 1700, 1800, 1850, and 2959 from Irgacure's series (IRGACURE and Irgacure are registered trademarks).

[0173] Examples of additional photoradical polymerization initiators include: 4-methoxyphenyl-2,4-bis(trichloromethyl)triazine, 2-(4-butoxystyryl)-5-trichloromethyl-1,3,4-oxadiazole, 9-phenylacridine, 9,10-benzophenone, a mixture of benzophenone and michler's ketone, a mixture of hexaarylbiimidazole and mercaptobenzimidazole, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropane-1-one, benzoyladium dimethyl ketal, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinylpropane-1-one, a mixture of 2,4-diethyloxanthone and methyl p-dimethylaminobenzoate, and a mixture of benzophenone and methyltriethanolamine.

[0174] After adding a photoradical polymerization initiator to the liquid crystal composition, polymerization can be carried out by irradiating ultraviolet light under an applied electric field. However, unreacted polymerization initiators or decomposition products of the polymerization initiators may cause display defects such as image retention. To prevent this, photopolymerization can also be carried out without adding a polymerization initiator. The preferred wavelength of the irradiated light is in the range of 150 nm to 500 nm. More preferably, the wavelength is in the range of 250 nm to 450 nm, and most preferably, the wavelength is in the range of 300 nm to 400 nm.

[0175] To prevent polymerization, polymerization inhibitors may be added when storing polymerizable compounds. Polymerizable compounds are typically added to the composition with the polymerization inhibitors still attached. Examples of polymerization inhibitors include hydroquinone, hydroquinone derivatives of methyl hydroquinone, 4-tert-butylcatechol, 4-methoxyphenol, and phenanthridine.

[0176] Optically active compounds have the following effects: they prevent reverse twisting by inducing a helical structure in liquid crystal molecules to impart the desired twist angle. The helical pitch can be adjusted by adding optically active compounds. For the purpose of adjusting the temperature dependence of the helical pitch, two or more optically active compounds can also be added. Preferred examples of optically active compounds include compounds (Op-1) to (Op-18). In compound (Op-18), ring F is 1,4-cyclohexylene or 1,4-phenylene, and R... 35 Alkyl groups having 1 to 10 carbon atoms. * indicates asymmetric carbon.

[0177] Antioxidants are effective in maintaining a high voltage retention rate. Preferred examples of antioxidants include compounds (AO-1) and (AO-2); Irganox 415, Irganox 565, Irganox 1010, Irganox 1035, Irganox 3114, and Irganox 1098 (trade names: BASF; Irganox is a registered trademark). Ultraviolet absorbers are effective in preventing a decrease in the upper temperature limit. Preferred examples of ultraviolet absorbers are benzophenone derivatives, benzoic acid ester derivatives, triazole derivatives, etc. Specific examples include: the following compounds (AO-3) and (AO-4); Tinuvin 329, Tinuvin P, Tinuvin 326, Tinuvin 234, Tinuvin 213, Tinuvin 400, Tinuvin 328 and Tinuvin 99-2 (trade names; BASF; TINUVIN and Tinuvin are registered trademarks); and 1,4-diazabicyclo[2.2.2]octane (DABCO).

[0178] Light stabilizers, such as sterically hindered amines, are preferred for maintaining high voltage retention rates. Preferred examples of light stabilizers include: compounds (AO-5), (AO-6), (AO-7), (AO-8), and (AO-9); Tinuvin 144, Tinuvin 765, Tinuvin 770DF, and Tinuvin 780 (trade name: BASF); LA-52, LA-57, LA-77Y, and LA-77G (trade name: ADEKA). Heat stabilizers are also effective for maintaining high voltage retention rates; a preferred example is Irgafos 168 (trade name: BASF; Irgafos is a registered trademark). To suit elements in a guest-host (GH) configuration, dichroic dyes such as azo dyes and anthraquinone dyes are added to the composition. Defoamers are effective in preventing foaming. Preferred examples of defoamers are dimethyl silicone oil and methylphenyl silicone oil.

[0179] In compound (AO-1), R 40 Alkyl groups having 1 to 20 carbon atoms, alkoxy groups having 1 to 20 carbon atoms, and -COOR 41 or -(CH2)2-COOR 41 Here, R 41 It is an alkyl group having 1 to 20 carbon atoms. In compounds (AO-2) and (AO-5), R 42 It is an alkyl group having 1 to 20 carbon atoms. In compound (AO-5), R 43 It is hydrogen, methyl or O · (Oxygen free radicals); Cyclic G 1 It is 1,4-cyclohexene or 1,4-phenylene; in compounds (AO-7) and (AO-8), the ring G 2 It is 1,4-cyclohexylene, 1,4-phenylene, or 1,4-phenylene with at least one hydrogen substituted by fluorine; in compounds (AO-5), (AO-7), and (AO-8), z is 1, 2, or 3.

[0180] 4. Liquid crystal display element

[0181] The liquid crystal composition can be used in liquid crystal display elements with operating modes such as PC, TN, STN, OCB, and PSA, and driven in an active matrix manner. The composition can also be used in liquid crystal display elements with operating modes such as PC, TN, STN, OCB, VA, and IPS, and driven in a passive matrix manner. These elements can be applied to any type of reflective, transmissive, or semi-transmissive display.

[0182] This composition is also suitable for nematic curvilinear aligned phase (NCAP) elements, where the composition is microencapsulated. This composition can also be used in polymer dispersed liquid crystal displays (PDLCDs) or polymer network liquid crystal displays (PNLCDs). In these compositions, a polymeric compound is added in large quantities. On the other hand, PSA-mode liquid crystal displays are manufactured when the proportion of the polymeric compound is 10% by weight or less based on the weight of the liquid crystal composition. A preferred proportion is in the range of 0.1% to 2% by weight. A more preferred proportion is in the range of 0.2% to 1.0% by weight. PSA-mode elements can be driven by methods such as active matrix or passive matrix driving. Such elements are also suitable for any type, including reflective, transmissive, and semi-transmissive types.

[0183] [Example]

[0184] 1. Examples of compound (1)

[0185] The present invention will be described in more detail by way of examples. The examples are typical examples, and therefore the present invention is not limited to the examples. Compound (1) is synthesized by the following sequence. The synthesized compound is identified by methods such as nuclear magnetic resonance (NMR) analysis. The physical properties of the compound or composition and the characteristics of the components are determined by the following methods.

[0186] NMR analysis: Bruker BioSpin DRX-500, Avance III HD 400, and Avance III 400 were used for the determination. 1 In the H-NMR determination, the sample is dissolved in a deuterated solvent such as CDCl3, and the determination is performed at room temperature, 500 MHz or 400 MHz, with a cumulative total of 16 determinations. Tetramethylsilane is used as an internal standard. 19 In F-NMR measurements, CFCl3 was used as an internal standard, and the measurements were performed with a cumulative count of 24. In the description of nuclear magnetic resonance spectra, s stands for singlet, d for doublet, t for triplet, q for quartet, quintet, sextet, m for multiplet, and br for broad.

[0187] Gas chromatography analysis: A Shimadzu GC-2010 gas chromatograph was used for the analysis. The column used was an Agilent Technologies DB-1 capillary column (60 m in length, 0.25 mm in inner diameter, 0.25 μm in film thickness). Helium (1 mL / min) was used as the carrier gas. The temperature of the sample vaporization chamber and the detector (flame ionization detector, FID) were both set to 300 °C. The sample was dissolved in acetone to prepare a 1% by weight solution, and 1 μL of the resulting solution was injected into the sample vaporization chamber. A Shimadzu GC solution system was used for recording.

[0188] Gas Chromatography Mass Spectrometry (hereinafter sometimes referred to as GC-MS): A Shimadzu QP-2010 Ultra gas chromatographic mass analyzer was used for the determination. A DB-1 capillary column (60 m in length, 0.25 mm in inner diameter, 0.25 μm in film thickness) manufactured by Agilent Technologies Inc. was used. Helium (1 mL / min) was used as the carrier gas. The temperature of the sample vaporization chamber was set to 300 °C, the temperature of the ion source was set to 200 °C, the ionization voltage was set to 70 eV, and the luminescence current was set to 150 μA. The sample was dissolved in acetone to prepare a 0.1 wt% solution, and 1 μL of the obtained solution was injected into the sample vaporization chamber. A Shimadzu GCMS Solution System was used as the recorder.

[0189] High Performance Liquid Chromatography (HPLC) analysis: A Prominence (LC-20AD; SPD-20A) column manufactured by Shimadzu Corporation was used for the determination. The column used was a YMC-Pack ODS-A (150 mm length, 4.6 mm inner diameter, 5 μm particle size) manufactured by YMC. The dissolution solution was a suitable mixture of acetonitrile and water. Suitable detectors included ultraviolet (UV) detectors, refractive index (RI) detectors, and corona detectors. When using a UV detector, the detection wavelength was set to 254 nm. The sample was dissolved in acetonitrile to prepare a 0.1% by weight solution, and 1 μL of this solution was introduced into the sample chamber. A Shimadzu C-R7Aplus recorder was used.

[0190] Ultraviolet-visible spectrophotometry: A Shimadzu PharmaSpec UV-1700 was used for the determination. The detection wavelength was set to 190 nm to 700 nm. The sample was dissolved in acetonitrile to prepare a 0.01 mmol / L solution, which was then placed in a quartz trough (1 cm optical path length) for determination.

[0191] Test samples: When determining phase structure and transition temperatures (clearing point, melting point, polymerization initiation temperature, etc.), the compound itself is used as the test sample. When determining the upper limit temperature, viscosity, optical anisotropy, dielectric anisotropy, and other physical properties of nematic phases, a mixture of the compound and the mother liquid crystal is used as the test sample.

[0192] When using a sample prepared by mixing the compound with the parent liquid crystal, the determination is performed as follows: A sample is prepared by mixing 15% by weight of the compound with 85% by weight of the parent liquid crystal. Based on the measured value of this sample, an extrapolated value is calculated according to the following equation and recorded: <Extrapolated value> = (100 × <Measured value of the sample> - <Weight % of parent liquid crystal> × <Measured value of parent liquid crystal>) / <Weight % of the compound>

[0193] When the crystallized (or lamellar phase) precipitates at 25°C under this ratio, the ratio of compound to parent liquid crystal is varied in the order of 10 wt%:90 wt%, 5 wt%:95 wt%, and 1 wt%:99 wt%, and the physical properties of the sample are determined according to the ratio at which the crystallized (or lamellar phase) no longer precipitates at 25°C. Furthermore, unless otherwise specified, the ratio of compound to parent liquid crystal is 15 wt%:85 wt%.

[0194] When the dielectric anisotropy of the compound is zero or positive, the following master liquid crystal (A) is used. The proportions of each component are expressed as weight % (%).

[0195] When the dielectric anisotropy of the compound is zero or negative, the following master liquid crystal (B) is used. The proportions of each component are expressed as weight % (%).

[0196] Master liquid crystal (C): Master liquid crystal (C) with the following fluorine compounds as components is also used. The proportion of components in master liquid crystal (C) is expressed as % by weight.

[0197] The ratio of compound to parent liquid crystal (C) was set at 20 wt%:80 wt%. When the crystallized (or laminar phase) precipitated at 25°C under this ratio, the ratio of compound to parent liquid crystal (C) was varied in the following order: 15 wt%:85 wt%, 10 wt%:90 wt%, 5 wt%:95 wt%, and 1 wt%:99 wt%. The physical properties of the sample were determined based on the ratio at which the crystallized (or laminar phase) no longer precipitated at 25°C. Furthermore, unless otherwise specified, the ratio of compound to parent liquid crystal (C) is 20 wt%:80 wt%.

[0198] Measurement Methods: The physical properties are measured using the following methods. Most of these methods are described in the JEITA Standard (JEITA·ED-2521B) formulated by the Japan Electronics and Information Technology Industries Association (JEITA). Modified versions of these standards are also used. Thin-film transistors (TFTs) are not installed in the TN element used for measurement.

[0199] (1) Phase structure: The sample was placed on a heating plate (Mettler FP-52 heating stage) of a melting point determination device including a polarizing microscope. The sample was heated at a rate of 3°C / min while the phase state and its changes were observed using a polarizing microscope to determine the type of phase.

[0200] (2) Transition Temperature (°C): The Diamond DSC system (Perkin Elmer) or the X-DSC7000 high-sensitivity differential scanning calorimeter (SII NanoTechnology) were used for measurement. The sample was heated and cooled at a rate of 3°C / min. The onset point of the endothermic or exothermic peak accompanying the phase change was determined by extrapolation, thus determining the transition temperature. The melting point and polymerization initiation temperature of the compound were also determined using this device. Sometimes, the temperature at which a compound transforms from a solid to a lamina, nematic, or other liquid crystal phase is simply referred to as the "lower limit temperature of the liquid crystal phase." Sometimes, the temperature at which a compound transforms from a liquid crystal phase to a liquid is simply referred to as the "clearing point."

[0201] Crystallization is represented by C. When crystallization can be divided into two types, they are represented as C1 or C2 respectively. Layered phases are represented by S, and nematic phases by N. When distinguishing phases such as layered A, layered B, layered C, and layered F phases, they are represented as S... A S B S C and S F The liquid (isotropic) phase is represented by I. The transition temperature is expressed, for example, as "C 50.0N 100.0I". This indicates that the temperature at which the crystalline phase transforms into the nematic phase is 50.0℃, and the temperature at which the nematic phase transforms into the liquid phase is 100.0℃.

[0202] (3) Compound compatibility: Samples were prepared by mixing the mother liquid crystal with the compound in proportions of 20 wt%, 15 wt%, 10 wt%, 5 wt%, 3 wt%, or 1 wt%. The samples were placed in glass vials and stored in a freezer at -10°C or -20°C for a certain period of time. The nematic phase of the sample was observed to be maintained or crystallized (or precipitated as a lamellae phase). The condition under which the nematic phase was maintained was used as a measure of compatibility. Sometimes the proportion of the compound or the temperature of the freezer may be changed as needed.

[0203] (4) Upper limit temperature of the nematic phase (T) NI Or NI; °C): The sample is placed on the heating plate of a melting point measuring device including a polarizing microscope and heated at a rate of 1 °C / min. The temperature at which a portion of the sample undergoes an autoneographic phase change to an isotropic liquid is measured. When the sample is a mixture of compound (1) and mother liquid crystal, the temperature is measured at T. NI The code is used to represent the sample. When the sample is a mixture of compound (1) and compounds selected from compounds (2) to (13) and compounds (21) to (24), the code NI is used. Sometimes the upper limit temperature of the nematic phase is simply referred to as the "upper limit temperature".

[0204] (5) Lower limit temperature of nematic phase (T) C (℃): Place the sample containing the nematic phase into a glass bottle and store it in a freezer at 0℃, -10℃, -20℃, -30℃, and -40℃ for 10 days, then observe the liquid crystal phase. For example, if the sample remains in the nematic phase at -20℃ but changes to a crystalline or lamellar phase at -30℃, then... C It is recorded as <-20℃. Sometimes the lower limit temperature of the nematic phase is simply referred to as the "lower limit temperature".

[0205] (6) Viscosity (volume viscosity; η; measured at 20°C; mPa·s): The E-type rotational viscometer manufactured by Tokyo Keiki Co., Ltd. was used for the measurement.

[0206] (7) Optical anisotropy (refractive index anisotropy; measured at 25°C; Δn): The measurement is performed using light with a wavelength of 589 nm via an Abbe refractometer with a polarizing plate mounted on the eyepiece. The sample is dropped onto the main prism after rubbing its surface in one direction. The refractive index (n∥) is measured when the direction of polarization is parallel to the direction of rubbing. The refractive index (n⊥) is measured when the direction of polarization is perpendicular to the direction of rubbing. The value of optical anisotropy (Δn) is calculated using the equation Δn = n∥ - n⊥.

[0207] (8) Specific resistance (ρ; measured at 25°C; Ωcm): 1.0 mL of the sample is injected into a container including the electrodes. A DC voltage (10V) is applied to the container, and the DC current is measured after 10 seconds. The specific resistance is calculated according to the following equation: (Specific resistance) = {(voltage) × (capacitance of the container)} / {(DC current) × (dielectric constant of vacuum)}.

[0208] (9) Voltage Retention Rate (VHR-1; measured at 25°C; %): The TN element used for the measurement has a polyimide alignment film, and the spacing (unit gap) between the two glass substrates is 5 μm. The element is sealed with an adhesive that is cured by ultraviolet light after the sample is placed in it. The element is charged by applying a pulsed voltage (5V, 60 μs). The decaying voltage is measured over a period of 16.7 milliseconds using a high-speed voltmeter, and the area A between the voltage curve per unit period and the horizontal axis is calculated. Area B is the area before decay. The voltage retention rate is expressed as a percentage of area A relative to area B.

[0209] (10) Voltage retention rate (VHR-2; measured at 80°C; %): The voltage retention rate is determined by the method described above, except that the measurement is performed at 80°C instead of at 25°C. The obtained result is indicated by the code VHR-2.

[0210] (11) Flicker rate (measured at 25°C; %): A Yokogawa Electric Corporation Multimedia Display Tester 3298F was used for the measurement. The light source was a Light Emitting Diode (LED). The sample was placed in an FFS element in normal black mode with a spacing (cell gap) of 3.5 μm between two glass substrates and an antiparallel rubbing direction. The element was sealed using an adhesive that hardens by ultraviolet light. A voltage was applied to the element, and the voltage at which the amount of light transmitted through the element is maximized was measured. While applying this voltage to the element, the sensor unit was brought close to the element, and the displayed flicker rate was read.

[0211] The methods for measuring the physical properties of samples with positive dielectric anisotropy and samples with negative dielectric anisotropy sometimes differ. The methods for measuring the properties when dielectric anisotropy is positive are described in measurements (12a) to (16a). The methods for measuring the properties when dielectric anisotropy is negative are described in measurements (12b) to (16b).

[0212] (12a) Viscosity (rotational viscosity; γ1; measured at 25°C; mPa·s; sample with positive dielectric anisotropy): The viscosity was measured according to the method described in M. Imai et al., “Molecular Crystals and Liquid Crystals” (Vol. 259, 37 (1995)). The sample was placed in a TN element with a torsion angle of 0 degrees and a spacing (cell gap) of 5 μm between the two glass substrates. A voltage was applied to the element in stages from 16 V to 19.5 V at 0.5 V increments. After 0.2 seconds without voltage applied, the voltage was repeatedly applied with only one rectangular pulse (rectangular pulse; 0.2 seconds) and no voltage applied (2 seconds). The peak current and peak time of the transient current generated by the application were measured. The rotational viscosity value was obtained based on these measured values ​​and equation (8) on page 40 of the paper by M. Imai et al. The value of dielectric anisotropy required in this calculation was obtained using the element on which the rotational viscosity was measured and by the method described below.

[0213] (12b) Viscosity (rotational viscosity; γ1; measured at 25°C; mPa·s; sample with negative dielectric anisotropy): The viscosity was measured according to the method described in M. Imai et al., “Molecular Crystals and Liquid Crystals” (Vol. 259, 37 (1995)). The sample was placed in a VA element with a spacing (cell gap) of 20 μm between two glass substrates. A voltage was applied to the element in stages from 39 V to 50 V, with each voltage applied 1 V. After 0.2 seconds without voltage applied, the voltage was repeatedly applied with only one rectangular pulse (rectangular pulse; 0.2 seconds) and no voltage applied (2 seconds). The peak current and peak time of the transient current generated by the application were measured. The value of rotational viscosity was obtained based on these measured values ​​and equation (8) on page 40 of the paper by M. Imai et al. The dielectric anisotropy required for this calculation was determined by the dielectric anisotropy term described below.

[0214] (13a) Dielectric anisotropy (Δε; measured at 25°C; for a sample with positive dielectric anisotropy): The sample is placed in a TN element with a spacing (cell gap) of 9 μm between two glass substrates and a twist angle of 80 degrees. A sine wave (10 V, 1 kHz) is applied to the element, and the dielectric constant (ε∥) along the long axis of the liquid crystal molecules is measured after 2 seconds. A sine wave (0.5 V, 1 kHz) is applied to the element, and the dielectric constant (ε⊥) along the short axis of the liquid crystal molecules is measured after 2 seconds. The value of dielectric anisotropy is calculated according to the equation Δε = ε∥ - ε⊥.

[0215] (13b) Dielectric anisotropy (Δε; measured at 25°C; for samples with negative dielectric anisotropy): The value of dielectric anisotropy is calculated according to the equation Δε = ε∥ - ε⊥. The dielectric constants (ε∥ and ε⊥) are determined as follows.

[0216] 1) Determination of dielectric constant (ε∥): A solution of 0.16 mL of octadecyltriethoxysilane in 20 mL of ethanol was coated onto a thoroughly cleaned glass substrate. After rotating the glass substrate using a rotator, it was heated at 150 °C for 1 hour. The sample was placed into a VA element with a 4 μm gap (cell gap) between two glass substrates, and the element was sealed using an adhesive that hardens under ultraviolet light. A sine wave (0.5 V, 1 kHz) was applied to the element, and the dielectric constant (ε∥) along the long axis of the liquid crystal molecules was measured after 2 seconds.

[0217] 2) Determination of dielectric constant (ε⊥): A polyimide solution was coated onto a thoroughly cleaned glass substrate. After calcining the glass substrate, the resulting alignment film was subjected to a rubbing treatment. The sample was placed into a TN element with a 9 μm gap (cell gap) and a twist angle of 80 degrees between two glass substrates. A sine wave (0.5 V, 1 kHz) was applied to the element, and the dielectric constant (ε⊥) along the short axis of the liquid crystal molecules was measured after 2 seconds.

[0218] (14a) Elastic constant (K; measured at 25°C; pN; for a sample with positive dielectric anisotropy): An HP4284A LCR meter manufactured by Yokogawa-Hewlett-Packard Co., Ltd. was used for the measurement. The sample was placed in a horizontal alignment element with a spacing (cell gap) of 20 μm between two glass substrates. A charge of 0 V to 20 V was applied to the element, and the electrostatic capacitance (C) and the applied voltage (V) were measured. The measured values ​​were fitted using equations (2.98) and (2.101) on page 75 of the "Liquid Crystal Device Handbook" (Nikkan Kogyo Shimbun), and K was obtained according to equation (2.99). 11 and K33 The value of K. Next, we will use the K we just calculated. 11 and K 33 The value is used in equation (3.18) on page 171 to calculate K. 22 The elastic constant K is obtained by calculating K in the following way. 11 K 22 and K 33 It is expressed as the average value.

[0219] (14b) Elastic constant (K) 11 and K 33 The test was conducted at 25°C. The sample was pN (with negative dielectric anisotropy). An EC-1 type elastic constant measuring instrument manufactured by TOYO Technica Co., Ltd. was used for the test. The sample was placed in a vertically aligned element with a 20 μm gap (unit spacing) between two glass substrates. A charge from 20 V to 0 V was applied to the element, and the electrostatic capacitance (C) and applied voltage (V) were measured. These values ​​were fitted using equations (2.98) and (2.101) on page 75 of the "Liquid Crystal Device Handbook" (Nikkan Kogyo Shimbun), and the value of the elastic constant was obtained according to equation (2.100).

[0220] (15a) Critical Voltage (Vth; measured at 25°C; V; for a sample with positive dielectric anisotropy): An LCD5100 luminance meter manufactured by Otsuka Electronics Co., Ltd. was used for the measurement. A halogen lamp was used as the light source. The sample was placed in a TN element in normal white mode with a spacing (cell gap) of 0.45 / Δn (μm) between two glass substrates and a twist angle of 80 degrees. The voltage (32Hz, rectangular wave) applied to the element was increased stepwise from 0V to 10V in units of 0.02V. Light was then irradiated onto the element from a vertical direction, and the amount of light transmitted through the element was measured. A voltage-transmittance curve was constructed with the transmittance at its maximum (100%) and at its minimum (0%). The critical voltage is expressed as the voltage at which the transmittance reaches 90%.

[0221] (15b) Critical Voltage (Vth; measured at 25°C; V; for samples with negative dielectric anisotropy): An LCD5100 luminance meter manufactured by Otsuka Electronics Co., Ltd. was used for the measurement. A halogen lamp was used as the light source. The sample was placed in a VA element with a 4 μm gap (unit gap) between two glass substrates and antiparallel rubbing directions, and the element was sealed with an adhesive that was cured by ultraviolet light. The voltage (60 Hz, rectangular wave) applied to the element was increased stepwise from 0 V to 20 V in units of 0.02 V. At this time, light was irradiated onto the element from a vertical direction, and the amount of light transmitted through the element was measured. A voltage-transmittance curve was prepared with the transmittance at the maximum of 100% and the transmittance at the minimum of 0%. The critical voltage is expressed as the voltage at which the transmittance reaches 10%.

[0222] (16a) Response time (τ; measured at 25°C; ms; for samples with positive dielectric anisotropy): An LCD5100 luminance meter manufactured by Otsuka Electronics Co., Ltd. was used for the measurement. A halogen lamp was used as the light source. The low-pass filter was set to 5 kHz. The sample was placed in a TN element in normally white mode with a spacing (cell gap) of 5.0 μm between two glass substrates and a twist angle of 80 degrees. A rectangular wave (60 Hz, 5 V, 0.5 s) was applied to the element. At this time, light was irradiated onto the element from a vertical direction, and the amount of light transmitted through the element was measured. The transmittance was considered to be 100% when the light amount reached its maximum and 0% when the light amount reached its minimum. Rise time (τr: rise time; milliseconds) is the time required for the transmittance to change from 90% to 10%. Fall time (τf: fall time; milliseconds) is the time required for the transmittance to change from 10% to 90%. The response time is represented by the sum of the rise time and fall time, calculated in the manner described above.

[0223] (16b) Response time (τ; measured at 25°C; ms; for samples with negative dielectric anisotropy): An LCD5100 luminance meter manufactured by Otsuka Electronics Co., Ltd. was used for measurement. A halogen lamp was used as the light source. The low-pass filter was set to 5 kHz. The sample was placed in a patterned vertical alignment (PVA) element with a spacing (cell gap) of 3.2 μm between two glass substrates and an antiparallel rubbing direction. The element was sealed using an adhesive that was cured by ultraviolet light. A voltage slightly exceeding the critical voltage was applied to the element for 1 minute, followed by irradiation at 23.5 mW / cm² for 8 minutes while applying a voltage of 5.6 V. 2 Ultraviolet light was applied to the element. A rectangular wave (60 Hz, 10 V, 0.5 seconds) was applied. Light was then irradiated onto the element from a vertical direction, and the amount of light transmitted through the element was measured. The transmittance was considered to be 100% when the light intensity reached its maximum and 0% when the light intensity reached its minimum. The response time was expressed as the time required for the transmittance to change from 90% to 10% (fall time; milliseconds).

[0224] [Synthesis example 1]

[0225] Synthesis of compound (No. 42)

[0226] Step 1: Synthesis of compound (S-2)

[0227] Under nitrogen atmosphere, compound (S-1) (50 g) and tetrahydrofuran (THF) (1000 ml) were added to a reactor and cooled to -60°C. Lithium n-butyl (1.6 M; hexane and cyclohexane solution; 220 ml) was added dropwise, and the mixture was stirred for 2 hours. Then, sulfur powder (10.6 g) was added, and the mixture was stirred for 2 hours while restoring the temperature to 25°C. Bromoacetaldehyde diethanolamide (65.4 g) was added, and the mixture was refluxed for 2 hours. The reaction mixture was injected into water and extracted with toluene. The organic layer was washed with water and dried with anhydrous magnesium sulfate. The solution was concentrated under reduced pressure, and the residue was purified by silica gel chromatography (toluene) to obtain compound (S-2) (84 g). Furthermore, compound (S-1) was sold and used by Combi-Blocks (Order Number: QJ-5097), etc.

[0228] Step 2: Synthesis of compound (S-3)

[0229] Under nitrogen atmosphere, compound (S-2) (75 g), polyphosphoric acid (100 g), and toluene (1000 ml) were added to a reactor and heated under reflux for 3 hours. The reaction mixture was then injected into water and extracted with toluene. The organic layer was washed with water and dried with anhydrous magnesium sulfate. The solution was concentrated under reduced pressure, and the residue was purified by silica gel chromatography (volume ratio, toluene:heptane = 2:3) to obtain compound (S-3) (42.0 g).

[0230] Step 3: Synthesis of compound (S-4)

[0231] Under nitrogen atmosphere, compound (S-3) (42 g) and THF (500 ml) were added to the reactor and cooled to -60°C. LDA (1 M; hexane, THF solution; 196 ml) was added dropwise, and the mixture was stirred for 2 hours. Iodine (54.7 g) was then added, and the mixture was stirred for 2 hours while restoring the temperature to 25°C. The reaction mixture was injected into water and extracted with toluene. The organic layer was washed with water and dried with anhydrous magnesium sulfate. The solution was concentrated under reduced pressure, and the residue was purified by silica gel chromatography (volume ratio, toluene:heptane = 2:3) to obtain compound (S-4) (60.0 g).

[0232] Step 4: Synthesis of compound (No. 42)

[0233] Under nitrogen atmosphere, compounds (S-4) (3g), (S-5) (2.8g), and toluene (80ml) were added to a reactor. Then, water (50ml), ethanol (50ml), Pd(PPh3)4 (0.3g), tetra-n-butyl ammonium bromide (TBAB) (0.28g), and potassium carbonate (2.4g) were added, and the mixture was heated to reflux for 6 hours. After the reaction, the mixture was extracted with toluene, washed with water, dried with anhydrous magnesium sulfate, and concentrated under reduced pressure to obtain a light brown solid. This solid was prepared into a solution, subjected to silica gel column chromatography (heptane:toluene = 3:2 by volume ratio), and recrystallized (with ethanol), thereby obtaining compound (No. 42) (3.9g) as colorless crystals. Furthermore, compound (S-5) was sold and used by Combi-Blocks (Order Number: FA-1772), etc.

[0234] 1H-NMR (δppm; CDCl3): 7.70(t,1H),7.64(d,1H),7.53(d,2H),7.44(d,1H),7.42(d,1H),7.3 1(d,1H),7.28(d,2H),4.27(q,2H),2.64(t,2H),1.69(sex,2H),1.44(t,3H),0.98(t,3H).

[0235] The physical properties of compound (No. 42) are as follows.

[0236] Transition temperature: C 36.1 S 257.4 I.

[0237] T NI =223.4℃; Δn=0.366; Δε=9.5; η=61.7mPa·s.

[0238] [Synthesis example 2]

[0239] Synthesis of compound (No. 43)

[0240] Under nitrogen atmosphere, compounds (S-4) (3g), (S-6) (2.8g), and toluene (80ml) were added to a reactor, followed by water (50ml), ethanol (50ml), Pd(PPh3)4 (0.3g), TBAB (0.28g), and potassium carbonate (2.4g). The mixture was heated under reflux for 6 hours. After the reaction, the mixture was extracted with toluene, washed with water, dried with anhydrous magnesium sulfate, and concentrated under reduced pressure to obtain a light brown solid. This solid was prepared into a solution, subjected to silica gel column chromatography (heptane:toluene = 3:2 by volume ratio), and recrystallized (with ethanol) to obtain compound (No. 43) (4.0g) as colorless crystals. Furthermore, compound (S-6) was sold and used by Aquila Pharmatech (Order Number: AN11274).

[0241] 1 H-NMR (δppm; CDCl3): 7.58(d,1H),7.55(d,1H),7.28(d,1H),7.24(d,1H),7.19(d,1H),6.23(t,1H),4.27(q,2H),2 .42(br,2H),2.35(d,1H),1.94(d,1H),1.9-1.8(m,1H),1.61(br,1H),1.42(t,3H),1.41-1.25(m,5H),0.93(t,3H).

[0242] The physical properties of compound (No. 43) are as follows.

[0243] Transition temperature: C 67.1 S 241.8 I.

[0244] T NI =228.7°C; Δn=0.320; Δε=7.5; eta=43.5mPa·s.

[0245] [Synthesis example 3]

[0246] Synthesis of compound (No. 52)

[0247] Under nitrogen atmosphere, compounds (S-4) (3g), (S-7) (2.8g), and toluene (80ml) were added to a reactor, followed by water (50ml), ethanol (50ml), Pd(PPh3)4 (0.3g), TBAB (0.28g), and potassium carbonate (2.4g). The mixture was heated under reflux for 6 hours. After the reaction, the mixture was extracted with toluene, washed with water, dried with anhydrous magnesium sulfate, and concentrated under reduced pressure to obtain a light brown solid. This solid was prepared into a solution, subjected to silica gel column chromatography (heptane:toluene = 3:2 by volume ratio), and recrystallized (with ethanol) to obtain compound (No. 52) (4.1g) as colorless crystals. Furthermore, compound (S-7) was purchased from A2B Chem (Order Number: AX54239) and used therein.

[0248] 1 H-NMR (δppm; CDCl3): 7.54(d,1H),7.53(d,1H),7.28(d,1H),7.04(d,1H),7.02(d,1H) ,4.26(q,2H),2.49(t,1H),1.89(t,4H),1.50-1.18(m,10H),1.05(q,2H),0.91(t,3H).

[0249] The physical properties of compound (No. 52) are as follows.

[0250] Transition temperatures: C 86.8, S 206.7, N 237.7, I.

[0251] T NI =220.7℃; Δn=0.253; Δε=6.8; η=57.8mPa·s.

[0252] [Synthesis Example 4]

[0253] Synthesis of compound (No. 44)

[0254] Under nitrogen atmosphere, compounds (S-4) (3g), (S-8) (2.8g), and toluene (80ml) were added to a reactor, followed by water (50ml), ethanol (50ml), Pd(PPh3)4 (0.3g), TBAB (0.28g), and potassium carbonate (2.4g). The mixture was heated under reflux for 6 hours. After the reaction, the mixture was extracted with toluene, washed with water, dried with anhydrous magnesium sulfate, and concentrated under reduced pressure to obtain a light brown solid. This solid was prepared into a solution, subjected to silica gel column chromatography (heptane:toluene = 3:2 by volume ratio), and recrystallized (with ethanol) to obtain compound (No. 44) (3.9g) as colorless crystals. Furthermore, compound (S-8) was sold and used by Aldrich (Order Number: AOBH99101C23), etc.

[0255] 1 H-NMR (δppm; CDCl3): 7.70(t,1H),7.64(d,1H),7.53(d,2H),7.44(d,1H),7.42(d, 1H),7.31(d,1H),7.28(d,2H),4.27(q,2H),2.71(q,2H),1.44(t,3H),1.29(t,3H).

[0256] The physical properties of compound (No. 44) are as follows.

[0257] Transition temperature: C 96.0 S 247.9 I.

[0258] T NI =220.4℃; Δn=0.356; Δε=9.5; η=82.7mPa·s.

[0259] [Synthesis example 5]

[0260] Synthesis of compound (No. 56)

[0261] Under nitrogen atmosphere, compounds (S-4) (3g), (S-9) (2.8g), and toluene (80ml) were added to a reactor, followed by water (50ml), ethanol (50ml), Pd(PPh3)4 (0.3g), TBAB (0.28g), and potassium carbonate (2.4g). The mixture was heated under reflux for 6 hours. After the reaction, the mixture was extracted with toluene, washed with water, dried with anhydrous magnesium sulfate, and concentrated under reduced pressure to obtain a light brown solid. This solid was prepared into a solution, subjected to silica gel column chromatography (heptane:toluene = 3:2 by volume ratio), and recrystallized (with ethanol) to obtain compound (No. 56) (4.1g) as colorless crystals. Furthermore, compound (S-9) was sold and used by Aldrich (Order Number: AMBH303C4B5C), etc.

[0262] 1 H-NMR (δppm; CDCl3): 7.70(t,1H),7.64(d,1H),7.53(d,2H),7.44(d,1H),7.42(d,1H),7.31(d,1H) ,7.28(d,2H),4.27(q,2H),2.66(t,2H),1.64(quint,2H),1.44(t,3H),1.39(sex,2H),0.95(t,3H).

[0263] The physical properties of compound (No. 56) are as follows.

[0264] Transition temperature: C 86.5 S 252.4 I.

[0265] T NI =215.4℃; Δn=0.336; Δε=8.5; η=63.7mPa·s.

[0266] [Synthesis example 6]

[0267] Synthesis of compound (No. 45)

[0268] Under nitrogen atmosphere, compound (S-4) (3g), compound (S-10) (2.8g), and toluene (80ml) were added to a reactor, followed by water (50ml), ethanol (50ml), Pd(PPh3)4 (0.3g), TBAB (0.28g), and potassium carbonate (2.4g). The mixture was heated to reflux for 6 hours. After the reaction was complete, the mixture was extracted with toluene, washed with water, dried with anhydrous magnesium sulfate, and concentrated under reduced pressure to obtain a light brown solid. This solid was prepared into a solution, subjected to silica gel column chromatography (heptane:toluene = 3:2 by volume ratio), and recrystallized (with ethanol) to obtain compound (No. 45) (4.0g) as colorless crystals. Furthermore, compound (S-10) was sold and used by Alfa Chemistry (Order Number: ACM163129144), etc.

[0269] 1 H-NMR (δppm; CDCl3): 7.70(t,1H),7.64(d,1H),7.53(d,2H),7.44(d,1H),7.42(d,1H),7.31(d,1H),7.28(d, 2H),4.27(q,2H),2.66(t,2H),1.64(quint,2H),1.44(t,3H),1.36(quint,2H),1.35(sex,2H),0.91(t,3H).

[0270] The physical properties of compound (No. 45) are as follows.

[0271] Transition temperature: C 78.6 S 253.6 I.

[0272] T NI =219.4℃; Δn=0.336; Δε=7.5; η=39.7mPa·s.

[0273] [Synthesis Example 7]

[0274] Synthesis of compound (No. 51)

[0275] Under nitrogen atmosphere, compound (S-4) (3g), compound (S-11) (2.8g), and toluene (80ml) were added to a reactor. Then, water (50ml), ethanol (50ml), Pd(PPh3)4 (0.3g), TBAB (0.28g), and potassium carbonate (2.4g) were added, and the mixture was heated to reflux for 6 hours. After the reaction, the mixture was extracted with toluene, washed with water, dried with anhydrous magnesium sulfate, and concentrated under reduced pressure to obtain a light brown solid. This solid was prepared into a solution, subjected to silica gel column chromatography (heptane:toluene = 3:2 by volume ratio), and recrystallized (with ethanol), thereby obtaining compound (No. 51) (4.1g) as colorless crystals. Furthermore, compound (S-11) was sold and used by A2B Chem (Order Number: BR63513), etc.

[0276] 1 H-NMR (δppm; CDCl3): 7.10(d,1H),7.53(d,2H),7.36(d,1H),7.30(d,2H),7.2 8(d,2H),4.29(q,2H),2.65(t,2H),1.69(sex,2H),1.45(t,3H),0.98(t,3H).

[0277] The physical properties of compound (No. 51) are as follows.

[0278] Transition temperature: C 83.0 S 229.2 I.

[0279] T NI =201.4℃; Δn=0.346; Δε=12.5; η=36.9mPa·s.

[0280] [Synthesis example 8]

[0281] Synthesis of compound (No. 8)

[0282] Under nitrogen atmosphere, compounds (S-4) (3g), (S-12) (2.3g), and toluene (80ml) were added to a reactor, followed by water (50ml), ethanol (50ml), Pd(PPh3)4 (0.3g), TBAB (0.28g), and potassium carbonate (2.4g). The mixture was heated under reflux for 6 hours. After the reaction, the mixture was extracted with toluene, washed with water, dried with anhydrous magnesium sulfate, and concentrated under reduced pressure to obtain a light brown solid. This solid was prepared into a solution, subjected to silica gel column chromatography (heptane:toluene = 3:2 by volume ratio), and recrystallized (with ethanol) to obtain compound (No. 8) (2.8g) as colorless crystals. Furthermore, compound (S-12) was purchased from Tokyo Chemical Industry (TCI) (Order Number: P1827) and used therein.

[0283] 1 H-NMR (δppm; CDCl3): 7.57(d,2H),7.37(d,1H),7.25(d,1H),7.23(d,2H),4.24(q,2H),2.61(t,2H),1.65(sex,2H),1.42(t,3H),0.96(t,3H).

[0284] The physical properties of compound (No. 8) are as follows.

[0285] Transition temperature: C 56.1 S 128.6 I.

[0286] T NI =81.4℃; Δn=0.246; Δε=12.5; η=25.9mPa·s.

[0287] [Synthesis Example 9]

[0288] Synthesis of compound (No. 46)

[0289] Step 1: Synthesis of compound (S-13)

[0290] Under nitrogen atmosphere, compound (S-1-1) (50 g) and THF (1000 ml) were added to a reactor and cooled to -60°C. Lithium n-butyl (1.6 M; n-hexane, cyclohexane solution; 222 ml) was added dropwise, and the mixture was stirred for 2 hours. Then, sulfur powder (11.0 g) was added, and the mixture was stirred for 2 hours while restoring the temperature to 25°C. Bromoacetaldehyde diethanolamide (66.4 g) was added, and the mixture was refluxed for 2 hours. The reaction mixture was injected into water and extracted with toluene. The organic layer was washed with water and dried with anhydrous magnesium sulfate. The solution was concentrated under reduced pressure, and the residue was purified by silica gel chromatography (toluene) to obtain compound (S-13) (84 g). Furthermore, compound (S-1-1) was sold and used by Combi-Blocks (Order Number: OR-3820), etc.

[0291] Step 2: Synthesis of compound (S-14)

[0292] Under nitrogen atmosphere, compound (S-13) (84 g), polyphosphoric acid (100 g), and toluene (1000 ml) were added to a reactor and heated under reflux for 3 hours. The reaction mixture was then injected into water and extracted with toluene. The organic layer was washed with water and dried with anhydrous magnesium sulfate. The solution was concentrated under reduced pressure, and the residue was purified by silica gel chromatography (volume ratio, toluene:heptane = 2:3) to obtain compound (S-14) (41.0 g).

[0293] Step 3: Synthesis of compound (S-15)

[0294] Under nitrogen atmosphere, compound (S-14) (41 g) and THF (500 ml) were added to the reactor and cooled to -60°C. LDA (1 M; hexane, THF solution; 196 ml) was added dropwise, and the mixture was stirred for 2 hours. Iodine (55.0 g) was then added, and the mixture was stirred for 2 hours while restoring the temperature to 25°C. The reaction mixture was injected into water and extracted with toluene. The organic layer was washed with water and dried with anhydrous magnesium sulfate. The solution was concentrated under reduced pressure, and the residue was purified by silica gel chromatography (volume ratio, toluene:heptane = 2:3) to obtain compound (S-15) (59.0 g).

[0295] Step 4: Synthesis of compound (No. 46)

[0296] Under nitrogen atmosphere, compounds (S-15) (3g), (S-5) (2.8g), and toluene (80ml) were added to a reactor, followed by water (50ml), ethanol (50ml), Pd(PPh3)4 (0.3g), TBAB (0.28g), and potassium carbonate (2.4g). The mixture was heated under reflux for 6 hours. After the reaction was complete, the mixture was extracted with toluene, washed with water, dried with anhydrous magnesium sulfate, and concentrated under reduced pressure to obtain a light brown solid. The solid was then dissolved and subjected to silica gel column chromatography (heptane:toluene = 3:2 by volume) and recrystallized (with ethanol) to obtain compound (No. 46) (3.8g) as colorless crystals.

[0297] 1 H-NMR (δppm; CDCl3): 7.69(t,1H),7.64(d,1H),7.53(d,2H),7.44(d,1H),7.42(d,1 H),7.31(d,1H),7.28(d,2H),4.04(s,3H),2.62(t,2H),1.67(sex,2H),0.98(t,3H).

[0298] The physical properties of compound (No. 46) are as follows.

[0299] Transition temperature: C 96.05 S 252.8 I.

[0300] T NI =214.4°C; Δn=0.376; Δε=10.5; η=64.7mPa·s.

[0301] [Synthesis Example 10]

[0302] Synthesis of compound (No. 47)

[0303] Step 1: Synthesis of compound (S-16)

[0304] Under nitrogen atmosphere, compound (No. 46) (10 g) and dichloromethane (200 ml) were added to a reactor and cooled to below 10°C. Boron tribromide (1 M; dichloromethane solution; 26 ml) was added dropwise, and the mixture was stirred for 2 hours. The reaction mixture was injected into water and extracted with ethyl acetate. The organic layer was washed with water and dried with anhydrous magnesium sulfate. The solution was concentrated under reduced pressure, and the residue was purified by silica gel chromatography (toluene: ethyl acetate = 9:1) to obtain compound (S-16) (8.5 g).

[0305] Step 2: Synthesis of compound (No. 47)

[0306] Under nitrogen atmosphere, compound (S-16) (3g), iodopropane (1.5g), potassium carbonate (K₂CO₃; 2g), and DMF (100ml) were added to a reactor and stirred at 60°C for 2 hours. The reaction mixture was injected into water and extracted with ethyl acetate. The organic layer was washed with water and dried with anhydrous magnesium sulfate. The solution was concentrated under reduced pressure, and the residue was purified by silica gel chromatography (toluene:heptane = 1:3) to obtain compound (No. 47) (2.8g).

[0307] 1 H-NMR (δppm; CDCl3): 7.69(t,1H),7.64(d,1H),7.53(d,2H),7.44(d,1H),7.42(d,1H),7.31(d,1H ),7.28(d,2H),4.16(t,2H),2.64(t,2H),1.82(sex,2H),1.69(sex,2H),1.09(t,3H),0.98(t,3H).

[0308] The physical properties of compound (No. 47) are as follows.

[0309] Transition temperature: C 81.53 S 246.7 I.

[0310] T NI =214.4°C; Δn=0.376; Δε=10.5; η=64.7mPa·s.

[0311] [Synthesis Example 11]

[0312] Synthesis of compound (No. 57)

[0313] Under nitrogen atmosphere, compound (S-16) (3g), allyl bromide (1.4g), potassium carbonate (K₂CO₃; 2g), and DMF (100ml) were added to a reactor and stirred at 60°C for 2 hours. The reaction mixture was injected into water and extracted with ethyl acetate. The organic layer was washed with water and dried with anhydrous magnesium sulfate. The solution was concentrated under reduced pressure, and the residue was purified by silica gel chromatography (toluene:heptane = 1:3) to obtain compound (No. 57) (2.7g).

[0314] 1H-NMR (δppm; CDCl3): 7.70(t,1H),7.64(d,1H),7.52(d,2H),7.43(d,1H),7.42(d,1H),7.31(d,1H),7.29 (d,2H),6.10(oct,1H),5.40(d,1H),5.29(d,1H),4.70(d,2H),2.64(t,2H),1.70(sex,2H),0.99(t,3H).

[0315] The physical properties of compound (No. 57) are as follows.

[0316] Transition temperature: C 60.56 S

[0317] T NI =214.4°C; Δn=0.376; Δε=10.5; η=64.7mPa·s.

[0318] [Synthesis Example 12]

[0319] Synthesis of compound (No. 60)

[0320] Step 1: Synthesis of compound (S-17)

[0321] Under nitrogen atmosphere, compound (S-20) (5g) and THF (100ml) were added to the reactor and cooled to -60°C. Lithium n-butyl (1.6M; n-hexane, cyclohexane solution; 24ml) was added dropwise, and the mixture was stirred for 2 hours. Then, sulfur powder (12g) was added, and the mixture was stirred for 2 hours while restoring the temperature to 25°C. Bromoacetaldehyde diethanolamide (7.4g) was added, and the mixture was refluxed for 2 hours. The reaction mixture was injected into water and extracted with toluene. The organic layer was washed with water and dried with anhydrous magnesium sulfate. The solution was concentrated under reduced pressure, and the residue was purified by silica gel chromatography (toluene) to obtain compound (S-17) (8.2g). Furthermore, compound (S-20) was sold and used by Combi-Blocks (Order Number: QC-7388), etc.

[0322] Step 2: Synthesis of compound (S-18)

[0323] Under nitrogen atmosphere, compound (S-17) (8.2 g), polyphosphoric acid (10 g), and toluene (100 ml) were added to a reactor and heated under reflux for 3 hours. The reaction mixture was then injected into water and extracted with toluene. The organic layer was washed with water and dried with anhydrous magnesium sulfate. The solution was concentrated under reduced pressure, and the residue was purified by silica gel chromatography (volume ratio, toluene:heptane = 2:3) to obtain compound (S-18) (4.2 g).

[0324] Step 3: Synthesis of compound (S-19)

[0325] Under nitrogen atmosphere, compound (S-18) (4.2 g) and THF (50 ml) were added to the reactor and cooled to -60°C. LDA (1 M; hexane, THF solution; 20 ml) was added dropwise, and the mixture was stirred for 2 hours. Iodine (5.7 g) was then added, and the mixture was stirred for 2 hours while restoring the temperature to 25°C. The reaction mixture was injected into water and extracted with toluene. The organic layer was washed with water and dried with anhydrous magnesium sulfate. The solution was concentrated under reduced pressure, and the residue was purified by silica gel chromatography (volume ratio, toluene:heptane = 2:3) to obtain compound (S-19) (6.1 g).

[0326] Step 4: Synthesis of compound (No. 60)

[0327] Under nitrogen atmosphere, compounds (S-19) (6.1 g), (S-5) (6.0 g), and toluene (160 ml) were added to a reactor, followed by water (100 ml), ethanol (100 ml), Pd(PPh3)4 (0.5 g), TBAB (0.7 g), and potassium carbonate (5.0 g). The mixture was heated under reflux for 6 hours. After the reaction was complete, the mixture was extracted with toluene, washed with water, dried with anhydrous magnesium sulfate, and concentrated under reduced pressure to obtain a light brown solid. The solid was then dissolved and subjected to silica gel column chromatography (heptane:toluene = 3:2 by volume) and recrystallized (with ethanol) to obtain compound (No. 60) (7.1 g) as colorless crystals.

[0328] 1 H-NMR (δppm; CDCl3): 7.72(t,1H),7.70(d,1H),7.54(d,2H),7.48(d,1H),7.4 4(d,1H),7.42(d,1H),7.29(d,2H),2.65(t,2H),1.70(sex,2H),0.99(t,3H).

[0329] The physical properties of compound (No. 60) are as follows.

[0330] Transition temperature: C 75.5 S 241.1 I.

[0331] T NI =167.4℃; Δn=0.285; Δε=23.5; η=29.1mPa·s.

[0332] [Synthesis Example 13]

[0333] Synthesis of compound (No. 134)

[0334] Under nitrogen atmosphere, compounds (S-4) (4g), (S-21) (5g), and toluene (90ml) were added to a reactor, followed by water (50ml), ethanol (50ml), Pd(PPh3)4 (0.4g), TBAB (0.3g), and potassium carbonate (3g). The mixture was heated under reflux for 6 hours. After the reaction was complete, the mixture was extracted with toluene, washed with water, dried with anhydrous magnesium sulfate, and concentrated under reduced pressure to obtain a light brown solid. The solid was then dissolved and subjected to silica gel column chromatography (heptane:toluene = 3:2 by volume) and recrystallization (ethanol), thereby obtaining compound (No. 134) (4.5g) as colorless crystals. Furthermore, the synthesis method of compound (S-21) is described in Chinese Patent Publication No. 105131972 and is based thereon.

[0335] 1 H-NMR (δppm; CDCl3): 7.69(t,1H),7.63(d,1H),7.52(d,2H),7.43(d,1H),7.42(d,1H),7.31(d,1H),7. 28(d,2H),5.88(m,1H),5.09(d,1H),5.01(d,1H),4.28(q,2H),2.75(t,2H),2.42(q,2H),1.44(t,3H).

[0336] The physical properties of compound (No. 134) are as follows.

[0337] Transition temperature: C 79.0 S 263.31 I.

[0338] T NI =231.4℃; Δn=0.366; Δε=7.5; η=39.1mPa·s.

[0339] [Synthesis Example 14]

[0340] Synthesis of compound (No. 135)

[0341] Under nitrogen atmosphere, compounds (S-4) (3.5 g), (S-22) (3.4 g), and toluene (90 ml) were added to a reactor, followed by water (50 ml), ethanol (50 ml), Pd(PPh3)4 (0.3 g), TBAB (0.35 g), and potassium carbonate (2.7 g). The mixture was heated under reflux for 6 hours. After the reaction was complete, the mixture was extracted with toluene, washed with water, dried with anhydrous magnesium sulfate, and concentrated under reduced pressure to obtain a light brown solid. The solid was then dissolved and subjected to silica gel column chromatography (heptane:toluene = 3:2 by volume) and recrystallized (with ethanol) to obtain compound (No. 135) (4.0 g) as colorless crystals.

[0342] 1 H-NMR (δppm; CDCl3): 7.57(d,1H),7.55(d,1H),7.28(d,1H),7.25(d,1H),7.19(d,1H),6.23(t,1H),4.27(q,2H),2 .42(br,2H),2.35(d,1H),1.95(d,1H),1.9-1.8(m,1H),1.61(br,1H),1.42(t,3H),1.40-1.30(m,3H),0.96(t,3H).

[0343] The physical properties of compound (No. 135) are as follows.

[0344] Transition temperature: C 89.6 S 217.3 I.

[0345] T NI =228.7°C; Δn=0.320; Δε=7.5; eta=43.5mPa·s.

[0346] [Comparative Example]

[0347] Compound (A) described in Patent Document 1 (International Publication No. 2016 / 132998) and compound (B) described in Patent Document 2 (International Publication No. 2017 / 064892) are designated as comparative examples.

[0348] [Physical properties of the examples and comparative examples]

[0349] The compound of this application (No. 42) synthesized in Synthesis Example 1 is used as an example. If the physical properties of the examples and comparative examples are summarized, it is as follows.

[0350] Compound (No. 42) exhibits a higher clarity (T) compared to compound (A) or compound (B). NIIt exhibits low viscosity (η), high dielectric anisotropy (Δε), and excellent values ​​for all physical properties. In particular, its viscosity (η) and clearing point (T) are both excellent. NI There is a trade-off relationship between dielectric anisotropy (Δε) and dielectric anisotropy (Δε), which usually makes it difficult to exhibit excellent properties. However, the compound of this application achieves this compared to the comparative compound, and can be said to have a very good balance of physical properties.

[0351] The following compounds can be synthesized by referring to the method described in the synthesis examples or the section "2. Synthesis of Compound (1)".

[0352] 2. Examples of the Composition

[0353] The invention is illustrated in more detail by way of examples of compositions. These examples are typical, and therefore the invention is not limited to these examples (use examples). For example, the invention includes, in addition to the compositions of use examples, mixtures of the compositions of use example 1 and use example 2. The invention also includes mixtures prepared by mixing at least two of the compositions of use examples. The compounds in the use examples are represented by codes based on the definitions in Table 2 below. In Table 2, the stereoconfiguration associated with 1,4-cyclohexylene is trans. The number in parentheses following the code in the use examples indicates the chemical formula to which the compound belongs. The code (-) refers to a liquid crystal compound that is different from compounds (1) to (13) and compounds (21) to (24). The proportion (percentage) of the liquid crystal compound is a weight percentage (wt%) based on the weight of the liquid crystal composition without additives. Finally, the physical properties of the compositions are summarized. The physical properties are determined according to the methods described above, and the measured values ​​are recorded directly (without extrapolation).

[0354] Table 2 shows the representation of compounds using codes.

[0355] R-(A1)-Z1-.....-Z n -(A n )-R′

[0356] [Usage Example 1]

[0357] NI=95.4°C; eta=16.7mPa·s; Δn=0.114; Δε=4.9.

[0358] [Usage Example 2]

[0359] NI = 105.7°C; η = 38.5 mPa·s; Δn = 0.128; Δε = 8.4.

[0360] [Usage example 3]

[0361] NI = 72.6°C; η = 24.8 mPa·s; Δn = 0.099; Δε = 8.1.

[0362] [Usage example 4]

[0363] NI = 82.0°C; η = 12.4 mPa·s; Δn = 0.132; Δε = 6.7.

[0364] [Usage example 5]

[0365] NI = 95.4°C; η = 16.2 mPa·s; Δn = 0.112; Δε = 4.9.

[0366] [Usage example 6]

[0367] NI = 107.5°C; η = 31.5 mPa·s; Δn = 0.128; Δε = 8.1.

[0368] [Usage example 7]

[0369] NI = 67.7°C; η = 24.2 mPa·s; Δn = 0.095; Δε = 8.0.

[0370] [Usage example 8]

[0371] NI = 82.3°C; η = 15.8 mPa·s; Δn = 0.138; Δε = 6.8.

[0372] [Usage example 9]

[0373] NI = 95.3°C; η = 18.2 mPa·s; Δn = 0.113; Δε = 4.9.

[0374] [Usage example 10]

[0375] NI = 105.7°C; η = 32.6 mPa·s; Δn = 0.126; Δε = 8.3.

[0376] [Usage Example 11]

[0377] NI=70.2°C; eta=24.4mPa·s; Δn=0.097; Δε=8.0.

[0378] [Usage Example 12]

[0379] NI=81.0°C; eta=11.4mPa·s; Δn=0.131; Δε=6.9.

[0380] [Usage Example 13]

[0381] NI=79.8℃; γ1=146mPa·s; Δn=0.108; Δε=-3.4.

[0382] [Usage Example 14]

[0383] NI=79.0℃; γ1=143mPa·s; Δn=0.120; Δε=-3.4. Industrial applicability

[0384] The liquid crystal compound of the present invention has excellent physical properties. Liquid crystal compositions containing this compound can be widely used in liquid crystal display elements such as personal computers and televisions.

Claims

A compound represented by formula (1); in the formula (1), R 1 and R 2 independently are alkyl having a carbon atom number of 1 to 20, in which alkyl at least one -CH2- can be replaced by -O- or -S-, at least one -(CH2)2- can be replaced by -CH=CH-, in which alkyl at least one hydrogen can be replaced by halogen, wherein, R 2 not methoxy; Ring A 1 independently 1,4-cyclohexylene, 1,4-cyclohexenylene, 1,4-phenylene, 1,3- cyclohexadiene-1,4-diyl, tetrahydropyran-2,5-diyl, 1,3-dioxane-2,5-diyl, pyrimidine-2,5-diyl, 2,6,7-trioxabicyclo[2.2.2]octane-1,4-diyl, naphthalene-2,6-diyl, or pyridine-2,5-diyl, at least one hydrogen on the rings being replaceable by halogen; Z 1 independently a single bond or an alkylene group having 1 to 4 carbon atoms, in which at least one -CH2- can be replaced by -O- or -COO-, and in which at least one -(CH2)2- can be replaced by -CH=CH- or -C≡C-, and in which at least one hydrogen can be replaced by halogen; a is 0, 1, 2 or 3. The compound of claim 1, wherein, in the formula (1), R 1 is an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms or an alkyl group having 1 to 10 carbon atoms in which at least one hydrogen is substituted with fluorine, R 2 is an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 2 to 9 carbon atoms, an alkenyl group having 2 to 10 carbon atoms or an alkyl group having 1 to 10 carbon atoms in which at least one hydrogen is substituted with fluorine; Ring A 1 independently 1,4-cyclohexylene, 1,4-cyclohexenylene, 1,4-phenylene, 1,4-phenylene substituted with at least one halogen, or tetrahydropyran-2,5-diyl; Z 1 independently a single bond, -(CH2)2-, -CH=CH-, -CF=CF-, -C≡C-, -COO-, -OCO-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -(CH2)4-, -(CH2)2CF2O-, -(CH2)2OCF2-, -CF2O(CH2)2-, -OCF2(CH2)2-, -CH=CH-(CH2)2-, or -(CH2)2-CH=CH-; a is 0, 1, 2 or 3. The compound of claim 1, represented by any one of formulae (1-1) to (1-4); in the formulae (1-1) to (1-4), R 1 is an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms or an alkyl group having 1 to 10 carbon atoms in which at least one hydrogen is substituted with fluorine; R 2 is an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 2 to 9 carbon atoms, an alkenyl group having 2 to 10 carbon atoms or an alkyl group having 1 to 10 carbon atoms in which at least one hydrogen is substituted with fluorine; Ring A 2 , Ring A 3 and Ring A 4 is independently 1,4-cyclohexylene, 1,4-cyclohexenylene, 1,4- phenylene, 1,4-phenylene substituted with at least one halogen, or tetrahydropyran-2,5-diyl; Z 2 , Z 4 and Z 5 is independently a single bond, -(CH2)2-, -CH=CH-, -CF=CF-, -C≡C-, -COO-, -OCO-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -(CH2)4-, -(CH2)2CF2O-, -(CH2)2OCF2-, -CF2O(CH2)2-, -OCF2(CH2)2-, -CH=CH-(CH2)2-, or -(CH2)2-CH=CH-. The compound of claim 3, wherein, in the formulae (1-1) to (1-4), R 1 is an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms or an alkyl group having 1 to 10 carbon atoms in which at least one hydrogen is substituted with fluorine; R 2 is an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 2 to 9 carbon atoms, an alkenyl group having 2 to 10 carbon atoms or an alkyl group having 1 to 10 carbon atoms in which at least one hydrogen is substituted with fluorine; Ring A 2 , Ring A 3 , and Ring A 4 is independently 1,4-cyclohexylene, 1,4-cyclohexenylene, 1,4- phenylene, 1,4-phenylene substituted with at least one halogen, or tetrahydropyran-2,5-diyl; Z 2 , Z 4 and Z 5 is independently a single bond, -(CH2)2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, or -OCH2-. The compound of claim 4, represented by any one of formula (1-1-1) to formula (1-4-1); in the formulae (1-1-1) to (1-4-1), R 1 is an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms or an alkyl group having 1 to 10 carbon atoms in which at least one hydrogen is substituted with fluorine; R 2 is an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 2 to 9 carbon atoms, an alkenyl group having 2 to 10 carbon atoms or an alkyl group having 1 to 10 carbon atoms in which at least one hydrogen is substituted with fluorine; ring A 2 , ring A 3 and ring A 4 independently 1,4-cyclohexylene, 1,4-cyclohexenylene, 1,4-phenylene, 1,4-phenylene substituted with at least one halogen, or tetrahydropyran-2,5-diyl. A liquid crystal composition having a negative dielectric anisotropy, comprising: at least one compound selected from the compound according to any one of claims 1 to 5; and at least one compound selected from the group consisting of compounds represented by formulae (5) to (13), in the formulae (5) to (13), R 13 and R 14 independently are an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, in which at least one -CH2- can be replaced by -O- and at least one hydrogen can be replaced by fluorine; and 13 and R 14 independently are an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, in which at least one -CH2- can be replaced by -O- and at least one hydrogen can be replaced by fluorine; and R 15 is hydrogen, fluorine, an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, in which at least one -CH2- can be replaced by -O-, and at least one hydrogen can be replaced by fluorine; 15 in which at least one -CH2- can be replaced by -O-, and at least one hydrogen can be replaced by fluorine; ring C 1 ring C 2 ring C 3 ring C 4 independently 1,4-cyclohexylene, 1,4-cyclohexenylene, 1,4-phenylene, tetrahydropyran-2,5-diyl or decahydronaphthalene-2,6-diyl; Ring C 5 and Ring C 6 is independently 1,4-cyclohexylene, 1,4-cyclohexenylene, 1,4-phenylene, tetrahydropyran-2,5-diyl, or decahydronaphthalene-2,6-diyl; Z 14 , Z 15 , Z 16 and Z 17 are independently a single bond, -COO-, -CH2O-, -OCF2-, -(CH2)2- or -OCF2-(CH2)2-; L 11 and L 12 is independently fluorine or chlorine; S 11 is hydrogen or methyl; X is -O-, -S-, -CH2-, -CHF-, -CF2-, -CH2CH2-, -CHFCH2-, -CH2CHF-, -CF2CH2-, -CH2CF2-, -CF2CHF-, -CHFCF2-, -CF2CF2-, -CH=CH-, -CF=CH-, -CH=CF- or -CF=CF-; j, k, m, n, p, q, r and s are independently 0 or 1, the sum of k, m, n and p is 1 or 2, the sum of q, r and s is 0, 1, 2 or 3, t and h are independently 1, 2 or 3. A liquid crystal display element comprising the liquid crystal composition according to claim 6.

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