Starting from the dimethyl acetal of acetone several 3-allyl-1,1,1-trifluoroacetylacetones (1) were synthesized in high yields by treatment with trifluoroacetic anhydride, ether exchange reaction of the resulting β-trifluoroacetyl-α-methylvinyl ether with allyl alcohols in the presence of silica gel, followed by Claisen rearrangement. Reaction of 1 with hydrazine hydrate gave an allyl-substituted pyrazole bearing a trifluoromethyl group in high yield.
以
丙酮的二甲基
缩醛为起点,通过
三氟乙酸酐处理,δ-三
氟乙酰基-δ-甲基
乙烯基醚与烯丙基醇在
硅胶存在下发生醚交换反应,然后进行克莱森重排,高产率地合成了几种 3-烯丙基-1,1,1-三
氟乙酰基
丙酮(1)。将 1 与
水合
肼反应,高产率地得到了带有三
氟甲基的烯丙基取代的
吡唑。