Cycloalkylurea derivative

A compound of formula (1):

• or a pharmaceutically acceptable salt thereof
• wherein
• R1 is optionally-substituted C6-10 aromatic carbocyclyl group, optionally-substituted 5- to 10-membered aromatic heterocyclyl group, optionally-substituted C3-6 saturated carbocyclyl group, optionally-substituted 4- to 10-membered saturated heterocyclyl group, or cyano;
• L1 is single bond, methylene (which may be optionally substituted with the same or different one or more C1-4 alky), —NR8—, —C(═O)—, —OC(═O)—, —SO—, —SO2—, —S—, or oxygen atom;
• R2 is hydrogen atom, hydroxy group, halogen atom, cyano, or optionally-substituted C1-4 alkyl;
• or
• when L1 is single bond, R1 and R2 may be combined together as a spiro ring to form optionally-substituted C3-6 saturated carbon ring or optionally-substituted 4- to 10-membered saturated heteroring;
• L2 is a single bond;
• R3 and R4 are each independently hydrogen atom, halogen atom, cyano, —(C═O)NR5R6, carboxy group, —(C═O)O—R7, optionally-substituted C1-4 alkyl, or optionally-substituted C1-4 alkoxy, wherein R3 and R4 may bind to the same carbon atom if chemically possible;
• or
• when R3 and R4 bind to different ring carbon atoms, R3 and R4 may be taken together via C1-6 alkylene to form a fused ring or a bridged ring;
• R5 to R7 are each independently hydrogen atom, halogen atom, or optionally-substituted C1-4 alkyl;
• R8 is each independently hydrogen atom or optionally-substituted C1-4 alkyl;
• n is an integer of 2;
• Ring G is optionally-substituted C6-10 aromatic carbocyclyl group, optionally-substituted 5- to 10-membered aromatic heterocyclyl group, optionally-substituted C3-6 saturated carbocyclyl group, or optionally-substituted 4- to 10-membered saturated heterocyclyl group;
• A1 is oxygen atom or sulfur atom;
• A2 is oxygen atom or —NR8—;
• A3 is nitrogen atom;
• and
• the bond accompanied with broken line is each independently single bond or double bond.