The synthesis and antiplatelet activity of a series of pyrazolopiperaz
inone nonpeptide fibrinogen receptor antagonists is reported. The sulf
onamide analog 6 (L-734,115), significantly inhibited ex vivo platelet
aggregation 24 h after oral administration at doses of 1.0 and 2.0 mg
/kg to dogs and rhesus monkeys, respectively. (C) 1997 Elsevier Scienc
e Ltd.