A compound of formula wherein A, B and D represent N, CH or CR 3, with the proviso that at least one of A, B or D are N; R 1 represents C 1 -C 4 alkyl substituted with from one up to the maximum number of fluorine or chlorine atoms; R 2 represents C1, CF 3, O(C 1 -C 3 alkyl), NH(C 1 -C 3 alkyl) or N(C 1 -C 3 alkyl) 2 in which each of the previous C 1 -C 3 alkyl groups is optionally substituted with from one up to the maximum number of fluorine atoms; R 3 represents H, F, Cl, Br, I, C 1 -C 3 alkyl or O(C 1 -C 3 alkyl) in which each of the previous C 1 -C 3 alkyl groups is optionally substituted with from one up to the maximum number of fluorine atoms; R 4 represents H, C 1 -C 3 alkyl (optionally substituted with alkoxy, benzyloxy or -OC R 7), or CO 2 R 6; R 5 represents H, C 1 -C 3 alkyl (optionally substituted with C 1 -C 3 alkoxy, F, CN or CO 2 R), OH, C 1 -C 3 alkoxy or CO 2 R 6, or R 4 and R 5 taken together represent -CH 2 CH 2 or -C CH 2 -; R 6 represents H or C 1 -C 3 alkyl; R 7 represents C 1 -C 3 alkyl; W represents O or S; Ar represents a phenyl group substituted with one to four substitutents independently selected from F, Cl, Br, I, NO 2, CN, SCF 3, SO 2 CF 3, C 1 -C 3 alkyl substituted with from one up to the maximum number of chlorine or fluorine atoms, or C 1 -C 3 alkoxy optionally substituted with from one up to the maximum number of chlorine or fluorine atoms; or represents and X and Y independently represent H, F, Cl, Br, I, NO 2, CN, SCF 3, SO 2 CF 3, C 1 -C 3 alkyl substituted with from one up to the maximum number of chlorine or fluorine atoms, or C 1 -C 3 alkoxy optionally substituted with from one up to the maximum number of chlorine or fluorine atoms. A, B and D represent N, CH or CR 3, with the proviso that at least one of A, B or D are N; R 1 represents C 1 -C 4 alkyl substituted with from one up to the maximum number of fluorine or chlorine atoms; R 2 represents C1, CF 3, O(C 1 -C 3 alkyl), NH(C 1 -C 3 alkyl) or N(C 1 -C 3 alkyl) 2 in which each of the previous C 1 -C 3 alkyl groups is optionally substituted with from one up to the maximum number of fluorine atoms; R 3 represents H, F, Cl, Br, I, C 1 -C 3 alkyl or O(C 1 -C 3 alkyl) in which each of the previous C 1 -C 3 alkyl groups is optionally substituted with from one up to the maximum number of fluorine atoms; R 4 represents H, C 1 -C 3 alkyl (optionally substituted with alkoxy, benzyloxy or -OC R 7), or CO 2 R 6; R 5 represents H, C 1 -C 3 alkyl (optionally substituted with C 1 -C 3 alkoxy, F, CN or CO 2 R), OH, C 1 -C 3 alkoxy or CO 2 R 6, or R 4 and R 5 taken together represent -CH 2 CH 2 or -C CH 2 -; R 6 represents H or C 1 -C 3 alkyl; R 7 represents C 1 -C 3 alkyl; W represents O or S; Ar represents a phenyl group substituted with one to four substitutents independently selected from F, Cl, Br, I, NO 2, CN, SCF 3, SO 2 CF 3, C 1 -C 3 alkyl substituted with from one up to the maximum number of chlorine or fluorine atoms, or C 1 -C 3 alkoxy optionally substituted with from one up to the maximum number of chlorine or fluorine atoms; or represents and X and Y independently represent H, F, Cl, Br, I, NO 2, CN, SCF 3, SO 2 CF 3, C 1 -C 3 alkyl substituted with from one up to the maximum number of chlorine or fluorine atoms, or C 1 -C 3 alkoxy optionally substituted with from one up to the maximum number of chlorine or fluorine atoms.