We report stereoselective five-step syntheses of cis-3-ethyl-3,5-dihydro-3,5-diphenyl-5-methyl-4H-pyrazol-4-one (cis-1b) and trans-3,5-diethyl-3,5-dihydro-3,5-diphenyl-4H-pyrazol-4-one (trans-1c). The key synthon was 1,3-diphenylpent-2-en-1-one (5b) synthesized in a new one-pot crossed aldol/dehydration reaction of acetophenone with propiophenone using titanium(IV) chloride/tributylamine, followed by treatment with methanesulfonyl chloride and triethylamine.
我们报告了立体选择性的五步合成cis-3-ethyl-3,5-dihydro-3,5-diphenyl-5-methyl-4H-pyrazol-4-one(cis-1b)和trans-3,5-diethyl-3,5-dihydro-3,5-diphenyl-4H-pyrazol-4-one(trans-1c)。关键合成单元是1,3-diphenylpent-2-en-1-one(5b),它是通过使用
氯化
钛(IV)/
三正丁胺的新的单锅交叉醇脱
水反应将
乙酰苯和
丙酮合成的,随后处理了甲
磺酰氯和
三乙胺。