Ring Transformation by Ring Chain Transfer VI<sup>1</sup>: Regioselective Synthesis of (ω-Aminoalkyl)pyrazoles from Semicyclic 3-Chloro-2-propeniminium Salts and Hydrazines
作者:Jörg Bohrisch、Michael Pätzel、C. Mügge、Jürgen Liebscher
DOI:10.1055/s-1991-28409
日期:——
Novel semicyclic 3-aryl-3-chloro-2-propeniminium perchlorates 6 are synthesized by treating semicyclic enaminones 1 (2-aroylmethylene-1-methylpyrrolidines, -piperidines and -azepanes) with phosphoryl chloride dimethylformamide. Reaction of these chloropropeniminium salts 6 with hydrazines 2 give regiospecifically either 3-(Ï-aminoalkyl)- or 5-(Ï-aminoalkyl)pyrazoles 5 or 10. The direction of these ring transformation reactions is governed by the nature of substituent of the hydrazine. The synthesis is especially useful in the preparation of 1-substituted 5-(Ï-aminoalkyl)pyrazoles 10.
新型半环 3-芳基-3-氯-2-丙烯亚胺高氯酸盐 6 是通过用二甲基甲酰胺磷酰氯处理半环烯酮 1(2-芳基亚甲基-1-甲基吡咯烷、-哌啶和-氮杂环庚烷)而合成的。这些氯丙烯亚胺盐 6 与肼 2 反应后,可以得到 3-(Ï-氨基烷基)- 或 5-(Ï-氨基烷基)吡唑 5 或 10。 这些环转化反应的方向受肼的取代基性质的影响。该合成方法尤其适用于制备 1-取代的 5-(Ï-氨基烷基)吡唑 10。