Formation and thermal reaction of O-(N-acetylbenzimidoyl)benzamidoxime: comparison with the formation of 3,5-disubstituted 1,2,4-oxadiazoles from O-acetylarylamidoximes and O-aroylacetamidoximes
作者:Ngan Sim Ooi、David A. Wilson
DOI:10.1039/p29800001792
日期:——
Acetylation of the free base gave the title compound, which underwent a thermal cyclisation, with loss of acetamide, to give 3,5-diphenyl-1,2,4-oxadiazole. The mechanism of this reaction, in diphenyl ether, closely paralleled the thermal cyclisation of O-acetylarylamidoximes and O-aroylacetamidoximes, and is thought to involve a polar cyclisation step followed by rate-determining proton transfer. 13C N.m.r.
通过N-氯-或N-溴-琥珀酰亚胺或卤素在苯甲酰胺肟上的作用,获得了O-(苯甲酰亚胺基)苯甲酰胺肟的盐。游离碱的乙酰化得到标题化合物,将其进行热环化,损失乙酰胺,得到3,5-二苯基-1,2,4-恶二唑。在二苯醚中,该反应的机理与O-乙酰基芳酰胺肟和O-芳酰基乙酰氨基肟的热环化非常相似,并且被认为涉及极性环化步骤,随后是速率确定质子转移。记录了32种肟,a胺肟和恶二唑衍生物的13 C Nmr光谱,并记录了肟,a胺肟的取代基化学位移,计算苯环上的O-乙酰基酰胺肟,5-甲基-1,2,4-恶二唑-3-基和3-甲基-1,2,4-恶二唑-5-基。