Patent ID: 7763661

Claim:
A compound of the formula I where R1 is NO 2 ; R2 is hydrogen, or; R3 is O-phenyl, and R4 is H; or R3 is H, and R4 is O-phenyl, in which the phenyl radical is unsubstituted or substituted by 1, 2, 3, 4 or 5 radicals selected from the group consisting of F, Cl, Br, I, NO 2 , alkyl having 1, 2, 3 or 4 carbon atoms, —SO qq CH 3 , —SO rr CF 3 , —CF 3 , —OCF 3 , —SF 5 , —CN or —COR13; qq is zero, 1 or 2; rr is zero, 1 or 2, ss is zero or 1; R5 is hydrogen; and salts thereof.