Selective transformation of nitriles into amides and carboxylic acids by an immobilized nitrilase
作者:Norbert Klempier、Anna de Raadt、Kurt Faber、Herfried Griengl
DOI:10.1016/s0040-4039(00)92623-6
日期:1991.1
Using an immobilized nitrilase from Rhodococcus sp. mild and selective hydrolysis of nitriles can be achieved even in the presence of acid or base sensitive groups under neutral conditions. This method is applicable to a broad range of substrates as exemplified by aliphatic, alicyclic, heterocyclic and carbohydrate type nitriles.
Michael Additions versus Cycloaddition Condensations with Ethyl Nitroacetate and Electron-Deficient Olefins
作者:Elena Trogu、Francesco De Sarlo、Fabrizio Machetti
DOI:10.1002/chem.200802652
日期:2009.8.10
nitroacetate (1) reacts with electron‐poor olefins in the presence of a base to give either the Michael adducts 3 or the isoxazoline cycloadducts 4, resulting from water elimination. The proportions of the two products depend on the reaction conditions and change in the course of the process. Kinetic profiles for the two reactions show that the cycloaddition‐condensations require long induction times that dramatically
Aromatic and aliphatic nitrile oxides are generated by the oxidation of α-hydroxyimino carboxylic acid with ammoniumhexanitratocerate(IV). They react with olefinic and acetylenic dipolarophiles to give the corresponding cycloaddition products in good yield. The oxidation of α-oxo aldoximes also affords α-oxo carbonitrile oxides.
Several improvements in the cycloaddition of carboethoxyformonitrile oxide (CEFNO) with different alkenes are observed in the ionic liquids [bmim][BF4] and [bmim][PF6]. The possibility of obtaining good yields of the corresponding isoxazolines opens the way towards parallel collections of glutamic acid (Glu) analogues. (C) 2003 Elsevier Science Ltd. All rights reserved.