A series of novel, highly potent alpha (v)beta (3) antagonists based on a t
hiophene scaffold and containing an acylguanidine as an Arg-mimetic is desc
ribed. A number of structural features, such as cyclic versus open guanidin
e and a variety of lipophilic side chains, carbamates, sulfonamides and bet
a -amino acids were explored with respect to inhibition of alpha (v)beta (3
) mediated cell adhesion and selectivity versus alpha (IIb)beta (3) binding
. In addition, compound 19 was found to be active in the TPTX model of oste
oporosis. (C) 2001 Published by Elsevier Science Ltd.