yields of 19% and 27%, respectively. Alkaline hydrolysis converts the 2-pentafluoroethyl group to trifluoroacetyl. The reaction mechanism, involving a diazafulvene intermediate, is analogous to that elucidated for (trifluoromethyl)imidazoles; however, the pentafluoroethyl group is markedly more reactive to hydrolysis than the trifluoromethyl group. For imidazole derivatives, the ratio of reactivities is
组胺和
L-组氨酸甲酯的N-三
氟乙酰基衍
生物被五
氟乙基自由基的光
化学环取代提供相应的2-和4-五
氟乙基化产物,产率分别为19%和27%。碱
水解将2-五
氟乙基转化为三
氟乙酰基。涉及二氮杂富烯中间体的反应机理类似于对(三
氟甲基)
咪唑的阐明。但是,五
氟乙基比三
氟甲基对
水解的反应性强。对于
咪唑衍
生物,反应性比率在C-2处为75,在C-4处为40。4-(五
氟乙基)
组胺的
水解得到双环产物4-(三
氟甲基)-6,7-二氢-
1H-咪唑并[4,5-c]-
吡啶,产率为65.4%。