from substituted aldoximes (mixture of E and Z) and alkynes, using alkyl nitrites under conventional heating conditions. The key nitrile oxide intermediates that are required for the synthesis of isoxazoles are formed by treatment of substituted aldoxime with either tert-butyl nitrite or isoamyl nitrite. The generated nitrile oxides underwent in situ [3+2] dipolar cycloaddition to the substituted alkynes
3-chloropropyne. Another key intermediate product is 1,3-dipole, which can be obtained fromaromaticaldehyde. After treatment with hydroxylamine hydrochloride and then sodium carbonate solution, aromaticaldehyde is converted to aldehyde oxime, which reacts with N-chlorosuccinimide (NCS) to afford aryl hydroximino chloride. 1,3-Dipole is eventually formed in situ while triethylamine (TEA) in DMF is added dropwise
摘要 以青藤碱盐酸盐和芳香醛为原料合成了一种新型结构的青藤碱异恶唑衍生物,需要六个步骤。以良好的收率获得了19个目标化合物。青藤碱盐酸盐在与氨中和反应和与3-氯丙炔取代反应后转化为4-炔基青藤碱,这是合成目标青藤碱异恶唑化合物的关键中间产物。另一个关键的中间产物是 1,3-偶极子,它可以从芳香醛中获得。用盐酸羟胺和碳酸钠溶液处理后,芳香醛转化为醛肟,与 N-氯代琥珀酰亚胺 (NCS) 反应生成芳基羟氨基氯化物。1,3-偶极子最终原位形成同时滴加 DMF 中的三乙胺 (TEA)。然后加入4-炔基青藤碱,通过1,3-偶极环加成反应作为关键步骤提供青藤碱异恶唑衍生物。所有目标化合物均通过熔点、1 H NMR、13 C NMR、HRMS和FT-IR光谱进行表征。
TiCl3OTf-[bmim]Br: a novel and efficient catalyst system for chemoselective one-pot synthesis of thioamides from arylaldoximes
作者:Jalil Noei、Ahmad R. Khosropour
DOI:10.1016/j.tetlet.2008.09.084
日期:2008.12
The combination of TiCl3OTf with 1-butyl-3-methylimidazolium bromide is found to be an efficient and novel catalytic system for chemoselective one-pot transformation of arylaldoximes to their corresponding thioamides in high to excellent yields.
Rearrangement of aldoximes to amides in water under air atmosphere catalyzed by water-soluble iridium complex [Cp*Ir(H<sub>2</sub>O)<sub>3</sub>][OTf]<sub>2</sub>
作者:Chunlou Sun、Panpan Qu、Feng Li
DOI:10.1039/c3cy00934c
日期:——
[Cp*Ir(H2O)3][OTf]2, a variety of aldoximes, including aromatic, aliphatic, conjugatedunsaturated and non-conjugated unsaturated, were converted into their corresponding amides in water with good to excellent yields. Further, the one-pot synthesis of amides from aldehydes, hydroxylamine hydrochloride and sodium carbonate via a tandem condensation–rearrangement reaction in water was also accomplished. Compared