Patent ID: 7563820

Claim:
A compound of Formula I, or a salt thereof: wherein R 1 , R 2 and R 3 are each independently selected from H, OH, C 1-6 alkyl, C 1-6 alkoxy, NH 2 , NH—C 1-6 alkyl, N(C 1-6 alkyl)(C 1-6 alkyl), SH, S—C 1-6 alkyl, NO 2 , CF 3 , OCF 3 and halo; R 4 is unsubstituted Ar, or Ar substituted with 1-4 substituents, independently selected from C 1-6 alkyl, C 1-6 alkoxy and halo; X is selected from (CH 2 CH 2 O) n and (CH 2 ) n , and n=1-4.