View all references ] They have general structural features characteristic of many natural substances and are important pharmacophores in the active ingredients of drugs. These include serine proteases inhibitor [ 2 2. Sielecki , TM ; Liu , J. ; Mousa , SA ; Racanelli , AL ; Hausner , EA ; Wexler , RR ; Olson , RE Synthesis and pharmacology of modified amidine isoxazoline glycoprotein IIb/IIIa receptor antagonists . Bioorg. Med. Chem. Lett. 2001 , 11 , 2201 – 2204 . [CrossRef], [ ...