Reactions of mercury(II) acetate with nitrogen compounds. Part 9. Oxidations of the bis-(4-nitrophenylhydrazone)s of some 1,3-diketones with mercury(II) acetate and lead(IV) acetate
作者:Richard N. Butler、John P. James
DOI:10.1039/p19820000553
日期:——
Oxidation of bis-(4-nitrophenylhydrazone)s of 1,3-diketones containing an α-CH between the hydrazone chains resulted in cyclisation with fragmentation, giving pyrazoles. The reaction is considered to involve dehydrogenation of the conjugated tautomeric enamine form of the bis-hydrazone, giving a cis-azo-hydrazonoalkene intermediate. When the postulated azo-hydrazonoalkene intermediate had trans-stereochemistry
链之间含有α-CH的1,3-二酮的双-(4-硝基苯基hydr)氧化会导致环化并断裂,生成吡唑。该反应被认为涉及双-的共轭互变异构烯胺形式的脱氢,得到顺式-偶氮-hydr烯链中间体。当假定的偶氮-hydr氮烯中间体具有反式时-立体化学,不利于环化,如在环己-1,3-二酮双-(4-硝基苯基hydr)的氧化中,偶氮-烯烃是稳定的并且是主要产物。当1,3-双bis的共轭烯胺互变异构形式不存在时,与3,3-二甲基戊烷-2,4-二酮双-(4-硝基苯基hydr)一样,不形成吡唑,the链表现为分离的单hydr。