Synthesis and biological evaluation of nonpeptide integrin antagonists containing spirocyclic scaffolds.

Analogues of isoxazoline alpha(v)beta(3) antagonist 1 designed to further restrict the four carbon alkyl tether were prepared by incorporating two spirocyclic scaffolds, 1-oxa-2-azaspiro[4,5]dec-2-ene and 1-oxa-2,7-diazaspiro[4,4]non-2-ene. Additional optimization provided potent antagonists of both alpha(v)beta(3) and alpha(5)beta(1) which are selective over GPIIb/IIIa.