A convenient preparative method was developed for the synthesis of 4-amino-3-furoxancarboxylic acid azide, which is a universal synthon for the preparation of functional furoxan derivatives. This method was used for preparing new azo-, azoxy-, azido-, cyano-, nitro-, carbonylamino-, and hydroxylamino-substituted furoxan derivatives, which have earlier been difficultly accessible.
Conventional methods generate nitrile oxides from oxime halides in organic solvents under basic conditions. However, the present work revealed that water‐assisted generation of nitrile oxides proceeds under mild acidic conditions (pH 4–5). Cycloadditions of nitrile oxides with alkynes and alkenes easily occurred in water without using catalysts, thus yielding isoxazoles and isoxazolines, respectively
A thermal decomposition of dimethyl nitromalonate to bis(carbomethoxy)furoxan was observed at about 170 °C. In the presence of dipolarophiles, an intermediate, methyl carbonocyanidate N-oxide MeOCOC≡N→O, could be trapped as cycloadducts in good yields by the 1,3-dipolar cycloaddition. Treatment of dimethyl nitromalonate in mesitylene at the refluxing temperature resulted in a formation of methyl 2-(hydroxyimino)-2-(2,4,6-trimethylphenyl)acetate.
Catalyst-Free Formation of Nitrile Oxides and Their Further Transformations to Diverse Heterocycles
作者:Luca De Angelis、Alexandra M. Crawford、Yong-Liang Su、Daniel Wherritt、Hadi Arman、Michael P. Doyle
DOI:10.1021/acs.orglett.0c04130
日期:2021.2.5
transfer from tert-butyl nitriteundermildconditions and without the use of a catalyst or an additive is reported. This transformation is broadly applicable to the synthesis of furoxans by dimerization and isoxazoles and isoxazolines by cycloaddition. This methodology is also applied for the millimole-scale synthesis of two biologically active compounds. The formation of the nitrile oxide from a diazoacetamide
The formation of furoxan-3,4-dicarboxamides from nitroacetamides
作者:Philip A. Harris、Arthur Jackson、John A. Joule
DOI:10.1016/s0040-4039(00)99199-8
日期:——
Secondary and tertiary nitroacetamides are converted by treatment with thionyl chloride alone into furoxan-3,4-dicarboxamides.
通过单独用亚硫酰氯处理,将仲和叔硝基乙酰胺转化为呋喃喃-3,4-二甲酰胺。
Base- and Copper-Catalysed Condensation of Primary Activated Nitro Compounds with Enolisable Compounds
作者:Elena Trogu、Luca Cecchi、Francesco De Sarlo、Luca Guideri、Fabio Ponticelli、Fabrizio Machetti
DOI:10.1002/ejoc.200900802
日期:2009.12
Primarynitrocompounds have not been employed as nitrile oxide precursors in reactions with active methylene compounds because the reagents commonly used as dehydrating agents also react with these dipolarophiles. However, the CuII-catalysed cycloaddition/condensation procedure has been shown to be viable with these substrates, leading directly to the expected polyfunctional isoxazoles provided nitro