Four-ring liquid crystal compound having tetrahydropyran and 2,2′,3,3′-tetrafluorobiphenyl, liquid crystal composition and liquid crystal display device

A compound represented by formula (1-1):

• wherein
• R1 and R2 are independently alkyl having 1 to 10 carbons or alkoxy having 1 to 9 carbons;
• the ring A2 is 1,4-cyclohexylene, 1,4-cyclohexenylene, 1,4-phenylene, tetrahydropyran-2,5-diyl, tetrahydropyran-3,6-diyl, 2-fluoro-1,4-phenylene, 3-fluoro-1,4-phenylene or 2,3-difluoro-1,4-phenylene;
• the ring G is tetrahydropyran-2,5-diyl or tetrahydropyran-3,6-diyl;
• and
• Z2 and Z3 are a single bond.

A compound represented by formula (1-2):

• wherein
• R1 and R2 are independently alkyl having 1 to 10 carbons or alkoxy having 1 to 9 carbons;
• the ring A1 is 1,4-cyclohexylene, 1,4-cyclohexenylene, 1,4-phenylene, tetrahydropyran-2,5-diyl, tetrahydropyran-3,6-diyl, 2-fluoro-1,4-phenylene, 3-fluoro-1,4-phenylene or 2,3-difluoro-1,4-phenylene;
• the ring G is tetrahydropyran-2,5-diyl or tetrahydropyran-3,6-diyl;
• and
• Z1 and Z2 are a single bond.

A compound represented by formula (1-3):

• wherein
• R1 and R2 are independently alkyl having 1 to 10 carbons or alkoxy having 1 to 9 carbons;
• the ring A3 is 1,4-cyclohexylene, 1,4-cyclohexenylene, 1,4-phenylene, tetrahydropyran-2,5-diyl, tetrahydropyran-3,6-diyl, 2-fluoro-1,4-phenylene, 3-fluoro-1,4-phenylene or 2,3-difluoro-1,4-phenylene;
• the ring G is tetrahydropyran-2,5-diyl or tetrahydropyran-3,6-diyl;
• and
• Z2 and Z4 are a single bond.