Isonitriles oxime

The following compounds are unaffected by bis(p-methoxyphenyl) telluroxide dithi-olanes, enamines, aldehydes, ketones, alcohols, pyrroles, indoles, amino acids, aromatic amines, monohydroxyarenes, esters, hindered thiocarbonates, isonitriles, oximes, arylhy-drazones, sulphides, and selenides. ... 

Nitriles, Isonitriles, Oximes, and Hydroxylamines Hydrazones, Osazones, and Derived Heterocycles Other Heterocyclic Derivatives... 

Pyrrolidines and pyrrolidinones can be synthesized on insoluble supports by intramolecular carbometallation of alkenes (Entry 1, Table 15.4) and by Ugi reaction of support-bound isonitriles with amines and 4-oxo acids (Entry 4, Table 15.4). In Entry 5 in Table 15.4, the pyrrolidinone ring is formed by intramolecular Diels-Alder reaction of a furan with a fumaric acid derivative. 2-Pyrrolidinones have also been prepared by treatment of resin-bound O-mesitylenesulfonyl cyclobutanone oximes with... 

Radical chemistry has witnessed remarkable progress since the mid 1980s [1], In addition to common radical C2 synthons such as alkenes and alkynes [2], several radical Cl synthons are also available, including carbon monoxide, isonitriles, and sulfonyl oxime ethers [3, 4]. As featured in Scheme 6.1, a variety of combinations of radical Cl and C2 synthons are now possible, which makes radical methodologies more attractive and permits the design and implementation of a wide range of multicomponent processes. 

Radical C1 synthons CO, isonitrile, sulfonyl oxime ether, etc. Scheme 6.1... 

Bis[4-methoxyphenyl] tellurium oxide was found to be a mild and highly selective oxidizing agent for the conversion of thiocarbonyl groups to carbonyl groups, thiols to disulfides, arylhydrazines to arenes, and 1,2- or 1,4-dihydroxyarenes to quinones. No reaction was observed with simple phenols, alcohols, enamines, amines (including pyrrole, indole, tryptophan, tyrosine, aniline, and dimethylaniline), oximes, dithiolanes, isonitriles, and 2,4-dinitrophenylhydrazones4. 

A synthesis of a set of 2-pyridylpyrroles has been described, involving annulation of 1,3-dicarbonyl compounds with 2-(aminomethyl)pyridine under acidic conditions, as illustrated by the construction of compound 437 (Equation 121) <20020L435>. Likewise, pyrroles have also been obtained from reactions between 1,3-diaryl-l,3-dicarbonyl compounds and imines or oximes promoted by the TiCU/Zn-system <2004SL2239>. Yet another approach involves rhodium-catalyzed reactions of isonitriles with 1,3-dicarbonyl synthons, which enables for instance preparation of fluorinated pyrroles <20010L421>. 

Oxidation. Bis(p-methoxyphenyl)telluroxide (1) is a mild and selective oxidant for conversion of xanthates, thiocarbamates, thioamides, and nonenolizable thiones into the corresponding oxo derivatives, and also of thiols into disulfides. Typically these reactions afford products in 70-100% yield. 1,2- and 1,4-Hydroquinones are oxidized by 1 to o- and p-quinones, respectively. Phenylhydroxylamine is oxidized to nitrosobenzene (90% yield). Phenols, amines, enamines, alcohols, oximes, dithiolanes, isonitriles, and 2,4-dinitrophenylhydrazones are unreactive. 

The condensation of organolithium reagents (2 equiv.) with glyoxylate-derived oxime ethers (182) provides a direct method for the synthesis of a- -hydroxy amino acids (equation 22). Both glyoxylic acid and glyoxylamide oxime ethers are compatible with this process. A(>hydroxyaminoacetamides are also product in low/moderate yields by the addition of isonitriles to oximes (oxime ethers) analogous to the four component condensation described by Ugi. ... 

Very recently, Kim and co-workers have reported a new useful radical acylation approach which uses a series of sulfonyl oxime ethers, some of which function as a viable radical Cl synthon. Unlike carbon monoxide and isonitriles, which operate as a radical acceptor/radical precursor type Cl synthon, sulfonyl oxime ethers... 

Isomers s. a. Oximes, Stereoisomers cw,trans-isomers s. Geospecificity, CIS- and trans-Oxido compounds Isonitrile dihalides... 

Nitrile carbon shifts are in the range of 115-125 ppm whereas in isonitriles the shifts are around 155-165 ppm. In oximes, the carbon in the C=N bond appears around 150-160 ppm and in isocyanates the carbon shift is in the region of 120-125 ppm. For hydrazones with the functionality C=N-N, the shifts are usually around 165 ppm. Methylene carbons adjacent to nitro groups generally appear near 70-80 ppm, and for methylene groups in nitrosoam-ines these appear around 45-55 ppm. 

The various classes of compounds featuring carbon-nitrogen multiple bonds that are substrates for organometallic addition comprise azomethines, immonium ions, nitrones, hydrazones, oxime ethers, amidinesimidoyl halides, nitriles, isonitriles, and cyanates. Dicyclohexylcarbodiimide is omitted here because it has been included in the carbonyl section (p.l 16) side by side with isocyanates and isothiocycanates. 

Isonitrile 19 was detected in ultraviolet (UV) and infrared (IR) studies at low temperatures. They speculated that azirine intermediate 21 may precede the formation of 19 and, indeed, LFP studies on 18 performed by Richard and co-workers allowed observation of an intermediate which was assigned to 21 on the basis of the similarity of its UV absorption spectra to that of the cyclohexadienone chro-mophore. The reaction was not quenchable by piperylene and is presumed to occur via the singlet manifold. The authors did not put forward a mechanism for the formation of 21, although it may be formed by initial ESIPT from the phenol to the cyano group to give tautomer 22, which can then rearrange to give 21. Similar products (substituted benzoxazoles) were observed via presumed initial ESIPT in structurally related o-hydroxy substituted aromatic oximes and oxime ethers. ... 

Included in this category are those weak bases usually considered as classical nitrogen compounds amines, amides, azo and azoxy compounds, imines, nitriles, oximes, nitro compounds, and isonitriles whether or not the nitrogen atom is necessarily the basic site in the molecules. 

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