Patent ID: 7160894

Claim:
A compound represented by the following formula (1) or a salt thereof: wherein R 1 represents hydrogen atom, chlorine atom, or hydroxyl group; X 1 . . . X 2 represents —CH(R 2 )—CH(R 3 )—; R 2 , R 3 , and R 4 independently represent hydrogen atom, or an alkyl group; A 1 , A 11 , A 2 , and A 21 independently represent hydrogen atom, or an alkyl group; Y represents —CH(A 3 )—, —CH(A 3 )—C(A 4 )(A 41 )—, —CH(A 3 )—C(A 4 )(A 41 )—C—(A 5 )(A 51 )—, or a single bond; A 3 , A 4 , A 41 , A 5 , and A 51 independently represent hydrogen atom, or an alkyl group; Z represents hydroxyl group, or —N(A 6 )(A 61 ); A 6 represents hydrogen atom, or an alkyl group, A 61 represents hydrogen atom, an alkyl group, an aralkyl group, an alkyl group substituted with carboxyl group, an alkyl group substituted with cyano group, an alkyl group substituted with hydroxyl group, an alkyl group substituted with an alkoxyl group, an alkyl group substituted with an amino group, an alkyl group substituted with aminocarbonyl group, or an alkyl group of which end is substituted with N(A 7 )(—X 3 —A 71 ), where —X 3 — represents carbonyl group, A 7 represents hydrogen atom, or an alkyl group, and A 71 represents an alkyl group, an aralkyl group, or an aryl group, or A 7 and A 71 may together become an alkylene group, or an alkylene group substituted with an alkyl group to form a ring; and groups in each of one or more combinations selected from the group consisting of combinations of A 6 and A 3 , A 6 and A 4 , A 6 and A 1 , A 6 and A 2 , A 2 and A 3 , A 2 and A 4 , A 6 and A 5 , A 3 and A 1 , and A 5 and A 1 may bind to each other to form a 5- or 6-membered ring.