Study of the reactivity of α-acylenaminoketones. Synthesis of pyrazoles
作者:Giuseppina Negri、Concetta Kascheres
DOI:10.1002/jhet.5570380116
日期:2001.1
obtaining substituted pyrazoles and determining which of the carbonyls would preferentially be attacked by the nucleophile. The reactions of compounds 1–4 with hydrazine reagents led to the formation of the pyrazoles 5–7a-q. Small amounts of 4-methylamino-2-pentenones 10a-q, amides 11a-q and pyrazoles 12a-q were also obtained in these reactions. The unexpected formation of pyrazoles 15d,h,q was detected
4-(甲基氨基)-3-戊烯-2-酮与重氮酮的反应以良好的收率得到了α-酰基亚氨基酮1-3。α-酰基亚氨基酮4的制备是通过用苯甲酰氯处理4-(叔丁基氨基)-3-戊烯-2-酮,然后与甲胺进行氨基转移反应来进行的。反应在五种不同的溶剂中进行,并进行了气相色谱/质谱分析,目的是获得取代的吡唑并确定哪些羰基化合物将优先受到亲核试剂的攻击。化合物1-4与肼试剂的反应导致形成吡唑5-7a-q。在这些反应中也获得了少量的4-甲基氨基-2-戊烯酮10a-q,酰胺11a-q和吡唑12a-q。当在α-酰基氨基酮4与肼试剂的反应中使用甲醇和N,N-二甲基甲酰胺作为溶剂时,检测到吡唑15d,h,q的意外形成。