Piperidine derivative, liquid crystal composition and liquid crystal display device

A compound, represented by formula (1):

• wherein, in formula (1),
• R1, R2, R3 and R4 are independently hydrogen or alkyl having 1 to 4 carbons;
• ring A1 and ring A2 are independently 1,4-cyclohexylene, 1,4-cyclohexenylene, 1,2-phenylene, 1,3-phenylene, 1,4-phenylene, naphthalene-1,3-diyl, naphthalene-1,4-diyl, naphthalene-1,5-diyl, naphthalene-1,6-diyl, naphthalene-1,7-diyl, naphthalene-1,8-diyl, naphthalene-2,3-diyl, naphthalene-2,6-diyl, naphthalene-2,7-diyl, decahydronaphthalene-2,6-diyl, dihydropyrane-2,5-diyl, tetrahydropyran-2,5-diyl, 1,3-dioxane-2,5-diyl, pyrimidine-2,5-diyl or pyridine-2,5-diyl, and in the rings, at least one piece of hydrogen may be replaced by halogen, alkyl having 1 to 5 carbons, alkoxy having 1 to 5 carbons, or alkyl having 1 to 5 carbons in which at least one piece of hydrogen is replaced by halogen;
• Z1 and Z3 are independently a single bond, —O—, or alkylene having 2 to 10 carbons, and in the alkylene, at least one —CH2— may be replaced by —O—, at least one —CH2—CH2— may be replaced by —CH═CH— or —CH≡CH—, and at least one hydrogen may be replaced by fluorine,
• Z2 is a single bond, or alkylene having 1 to 10 carbons, and in the alkylene, at least one —CH2— may be replaced by —O—, at least one —CH2—CH2— may be replaced by —CH═CH— or —CH≡CH—, and at least one hydrogen may be replaced by fluorine;
• and
• n is 0, 1 or 2.