Synthesis of novel 5-substituted pyrazole derivatives as cannabinoid antagonists

A facile seven-step sequence was developed from 4′-bromopropiophenone, utilizing a Suzuki-type coupling with an alkene, to give several novel 5-substituted pyrazole derivatives in overall yields of 11–31%. They are potent CB1 antagonists and have binding affinities similar to SR 141716A. Like SR 141716A, they may prove to be clinically useful for the treatment of obesity.