نتایج جستجو برای: substituted nitrile oxide
تعداد نتایج: 216363 فیلتر نتایج به سال:
Alkylidenepyrrolidines 1, 21, 24 and 26 undergo reactions with nitrile oxides and nitrilimines or their precursors to give a range of novel heterocyclic compounds. With alkylidenepyrrolidine ester 1, nitrolic acids give products in which the liberated nitrous acid reacts with the alkylidenepyrrolidine, followed by two cycloadditions to give adducts 3. In contrast, hydroximoyl chlorides give iso...
Studies on the synthesis of macrosphelide B via an intramolecular nitrile oxide-olefin cycloaddition (INOC) is described. In particular, an asymmetric INOC approach using phase transfer catalysts seems to be a potentially efficient and versatile procedure for the construction of the macrolactone skeleton of macrosphelide B in terms of facial selectivity. Our preliminary and unprecedented stereo...
The [3 + 2] and [3 + 3] cyclodimerisation processes of small nitrile oxides, XCNO (X = F, Cl, Br, CN, CH(3)) are investigated by ab initio coupled cluster theory at the CCSD, CCSD(T) and MR-AQCC levels for the first time. The favoured dimerisation process is a multi-step reaction to furoxans (1,2,5-oxadiazole-2-oxides) involving dinitrosoalkene-like intermediates with diradical character. The r...
Simple Access to Isoxazole-Containing Heterocyclic Hybrids: Isoxazole/Oxazole and Isoxazole/Pyridine
Abstract The synthesis of substituted isoxazole–oxazole hybrids by the noncatalytic reaction methyl 2-diazo-2-(alkyl/aryl/hetarylisoxazol-5-yl)acetates with alkyl and aryl cyanides has been reported. According to DFT calculations, proceeds through intermediate formation a nitrile ylide its subsequent cyclization at carbonyl oxygen. acrylonitrile 2-diazo-2-(isoxazol-5-yl)acetate quite differentl...
In this article, we describe the process of binding riboflavin to a simple tetradents ligand substituted in α- position from TPAs types, by reacting bromotetraacetate with TPA one pyridine rings nitrile group and two other halogen atoms. This type ligands showed very important properties for activation transfer oxygen substrate presence iron salt. After were obtained, was reduced an amine where...
Abstract This thesis is concerned with the synthesis of -sultams and the development of new routes for the synthesis of bicyclic versions of these molecules as potential anti-bacterials. The synthesis of 1-azetines, 1,2-thiazetin-1,1-dioxides and isothiazol-1,1-dioxides as precursors of bicyclic heterocycles is described. 1-Azetines were synthesised from azetidin-2-ones prepared via the [2+2] c...
Decarbonylation-promoted Ru nanoparticle formation from Ru3(CO)12 on a basic K-doped Al2O3 surface was investigated by in situ FT-IR and in situ XAFS. Supported Ru3(CO)12 clusters on K-doped Al2O3 were converted stepwise to Ru nanoparticles, which catalyzed the selective hydrogenation of nitriles to the corresponding primary amines via initial decarbonylation, the nucleation of the Ru cluster c...
Precursors of 3-pyridylnitrene and 2- and 4-pyrimidinylcarbenes all afford mixtures of 2- and 3-cyanopyrroles on flash vacuum thermolysis, but 3-cyanopyrroles are the first-formed products. 3-Quinolylnitrenes and 4-quinazolinylcarbenes similarly afford 3-cyanoindoles. 2-Pyrimidinylcarbenes rearrange to 3-pyridylnitrenes, but 4-pyrimidinylcarbenes and 4-quinazolinylcarbenes do not necessarily re...
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