Patent ID: RE44338

Claim:
A compound of Formula III: or a pharmaceutically acceptable salt thereof, wherein R 3 is Br, I, F, 125 I, 131 I, 123 I, 18 F, 76 Br, 77 Br of or Sn(alkyl) 3 ; and R 1 and R 2 are independently hydrogen, C 1-4 alkyl , C 2-4 aminoalkyl, C 1-4 haloalkyl, haloarylalkyl, or R 1 and R 2 are taken together with the nitrogen to which they are attached to form a 5- to 7-member heterocyclic ring optionally having O, S , or NR 5 in said ring, where R 5 is hydrogen or C 1-4 alkyl.