A compound of formula I: wherein, in the formula I, R represents a = 0, 1, 2, 3, 4, 5 or 6; R 1 represents C 2 -C 8 alkyl, C 2 -C 8 alkenyl, C 2 -C 8 alkynyl, (CH 2 )nO(CH 2 )m, aryl, substituted aryl, heteroaryl, or substituted heteroaryl, wherein in the group b, c = 0, 1, 2, 3, 4, 5 or 6, and in the group (CH 2 )nO(CH 2 )m, n, m = 1, 2, 3, 4, 5 or 6; R 2 represents hydrogen, halogen, trifluoromethyl, C 1 -C 8 alkoxy, C 1 -C 8 alkyl, nitro, sulfonamido, amino or nitrile; R 3 represents C 1 -C 8 alkyl, C 1 -C 8 alkoxy, C 2 -C 8 alkenyloxy, C 2 -C 8 alkynyloxy, (C 1 -C 6 )O(C 1 -C 6 ), phenyl, substituted phenyl, heteroaryl or substituted heteroaryl, wherein in the group b, c = 0, 1, 2, 3, 4, 5 or 6; R 4 represents aryl, substituted aryl, phenylsulfonyl, heteroaryl, substituted heteroaryl, nitrile, trifluoromethyl, C 1 -C 8 alkoxy, C 1 -C 8 nitrate group, or C 1 -C 8 alkyl; R 5 represents aryl, substituted aryl, heteroaryl, substituted heteroaryl, nitrile, trifluoromethyl, C 1 -C 8 alkoxy, C 1 -C 8 nitrate group, C 1 -C 8 alkyl, C 1 -C 8 alkenyl, C 1 -C 8 alkynyl, or (CH 2 )nO(CH 2 )m, wherein R 3 , R 4 , a, m, n are as defined above; R 6 and R 7 represent hydrogen, C 1 -C 8 alkoxy or C 1 -C 8 alkyl; R 8 and R 9 represent hydrogen, C 1 -C 8 alkoxy, C 1 -C 8 nitrate group, or C 1 -C 8 alkyl; the substituted aryl refers to an aryl substituted with one or more selected from the group consisting of hydroxy, C 1 -C 6 alkyl, C 1 -C 6 alkoxy, halogen, nitro, amino, nitrile, trifluoromethyl, -CH=CHCO 2 R 11 , and each substituent may be the same or different, wherein R 11 represents hydrogen or C 1 -C 6 alkyl; the substituted heteroaryl is a heteroaryl optionally substituted with one or more selected from the group consisting of C 1 -C 6 alkyl, C 1 -C 6 alkoxy, halogen, and each substituent may be the same or different. wherein, in the formula I, R represents a = 0, 1, 2, 3, 4, 5 or 6; R 1 represents C 2 -C 8 alkyl, C 2 -C 8 alkenyl, C 2 -C 8 alkynyl, (CH 2 )nO(CH 2 )m, aryl, substituted aryl, heteroaryl, or substituted heteroaryl, wherein in the group b, c = 0, 1, 2, 3, 4, 5 or 6, and in the group (CH 2 )nO(CH 2 )m, n, m = 1, 2, 3, 4, 5 or 6; R 2 represents hydrogen, halogen, trifluoromethyl, C 1 -C 8 alkoxy, C 1 -C 8 alkyl, nitro, sulfonamido, amino or nitrile; R 3 represents C 1 -C 8 alkyl, C 1 -C 8 alkoxy, C 2 -C 8 alkenyloxy, C 2 -C 8 alkynyloxy, (C 1 -C 6 )O(C 1 -C 6 ), phenyl, substituted phenyl, heteroaryl or substituted heteroaryl, wherein in the group b, c = 0, 1, 2, 3, 4, 5 or 6; R 4 represents aryl, substituted aryl, phenylsulfonyl, heteroaryl, substituted heteroaryl, nitrile, trifluoromethyl, C 1 -C 8 alkoxy, C 1 -C 8 nitrate group, or C 1 -C 8 alkyl; R 5 represents aryl, substituted aryl, heteroaryl, substituted heteroaryl, nitrile, trifluoromethyl, C 1 -C 8 alkoxy, C 1 -C 8 nitrate group, C 1 -C 8 alkyl, C 1 -C 8 alkenyl, C 1 -C 8 alkynyl, or (CH 2 )nO(CH 2 )m, wherein R 3 , R 4 , a, m, n are as defined above; R 6 and R 7 represent hydrogen, C 1 -C 8 alkoxy or C 1 -C 8 alkyl; R 8 and R 9 represent hydrogen, C 1 -C 8 alkoxy, C 1 -C 8 nitrate group, or C 1 -C 8 alkyl; the substituted aryl refers to an aryl substituted with one or more selected from the group consisting of hydroxy, C 1 -C 6 alkyl, C 1 -C 6 alkoxy, halogen, nitro, amino, nitrile, trifluoromethyl, -CH=CHCO 2 R 11 , and each substituent may be the same or different, wherein R 11 represents hydrogen or C 1 -C 6 alkyl; the substituted heteroaryl is a heteroaryl optionally substituted with one or more selected from the group consisting of C 1 -C 6 alkyl, C 1 -C 6 alkoxy, halogen, and each substituent may be the same or different. <EOS>