Liquid crystal compound having chroman ring, liquid crystal composition comprising the compound and liquid crystal display device comprising the composition

A compound represented by any one of formulas (1-1) to (1-5):

• where Ra is hydrogen, C1-C10 alkyl, C1-C10 alkoxy or C2-C10 alkenyl;
• Rb is halogen, —CN, C1-C10 alkyl (at least one hydrogen of which is replaced by halogen), C2-C10 alkenyl (at least one hydrogen of which may be replaced by halogen), or C1-C10 alkoxy (at least one hydrogen of which may be replaced by halogen);
• each of A1, A2, A3 and A4 is independently 1,4-cyclohexylene, 1,3-dioxane-2,5-diyl, pyrimidine-2,5-diyl or 1,4-phenylene (any hydrogen of which may be replaced by fluorine);
• each of Z1, Z2, Z3 and Z4 is independently a single bond, —CH2CH2—, —CH2O—, —OCH2—, —CF2CH2—, —CH2CF2—, —CF2O— or —OCF2—;
• X1 is hydrogen or fluorine;
• and each of Y1, Y2, Y3, Y4 and Y5 is independently hydrogen, halogen or methyl.

A compound represented by any one of formulas (1-6) to (1-10):

• where Ra is hydrogen, C1-C10 alkyl, C1-C10 alkoxy or C2-C10 alkenyl;
• Rb is halogen, —CN, C1-C10 alkyl (at least one hydrogen of which is replaced by halogen), C1-C10 alkoxy (at least one hydrogen of which may be replaced by halogen), or C2-C10 alkenyl (at least one hydrogen of which may be replaced by halogen);
• each of A1, A2, A3 and A4 is independently 1,4-cyclohexylene, 1,3-dioxane-2,5-diyl, pyrimidine-2,5-diyl or 1,4-phenylene (any hydrogen of which may be replaced by fluorine);
• each of Z1, Z2, Z3 and Z4 is independently a single bond, —CH2CH2—, —CH2O—, —OCH2—, —CF2CH2—, —CH2CF2—, —CF2O— or —OCF2—;
• X1 is hydrogen or fluorine;
• and each of Y1, Y2, Y3, Y4 and Y5 is independently hydrogen, halogen or methyl.

A compound represented by any one of formulas (1-11) to (1-15):

• where Ra is hydrogen, C1-C10 alkyl, C1-C10 alkoxy or C2-C10 alkenyl;
• Rb is halogen, —CN, C1-C10 alkyl (at least one hydrogen of which is replaced by halogen), C1-C10 alkoxy (at least one hydrogen of which may be replaced by halogen), or C2-C10 alkenyl (at least one hydrogen of which may be replaced by halogen);
• each of A1, A2, A3 and A4 is independently 1,4-cyclohexylene, 1,3-dioxane-2,5-diyl, pyrimidine-2,5-diyl or 1,4-phenylene (any hydrogen of which may be replaced by fluorine);
• each of Z1, Z2, Z3 and Z4 is independently a single bond, —CH2CH2—, —CH2O—, —OCH2—, —CF2CH2—, —CH2CF2—, —CF2O— or —OCF2—;
• X1 is hydrogen or fluorine;
• and each of Y1, Y2, Y3, Y4 and Y5 is independently hydrogen, halogen or methyl.