Patent ID: 7196220

Claim:
A compound of the formula wherein R 1 is hydrogen, lower alkyl, aryl lower alkyl, or aryl; R 2 is hydrogen, lower alkyl, aryl lower alkyl, or aryl; wherein at least one of R 1 and R 2 is aryl; R 3 is hydrogen or lower alkyl; R 4 is hydrogen, lower alkyl, aryl lower alkyl or aryl; R 5 and R 6 are independently hydrogen or lower alkyl, or R 5 and R 6 taken together with the carbon atoms to which they are attached form a ring containing up to 10 ring carbon atoms and up to a total of 18 carbon atoms; R 7 is hydroxy, lower alkoxy or NR 8 R 9 ; R 8 is hydrogen or lower alkyl; and R 9 is hydrogen or lower alkyl. wherein said compound has an affinity for bone.