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LH-Azirine

Oxirene (2) is one of a number of heterocycles in which the CH2 group of cyclopropene has been replaced by a group or element associated with Groups V or VI of the periodic table. Replacement of the CH2 group of cyclopropene by an NH group gives lH-azirine... [Pg.120]

A 13C-labeling study showed that an lH-azirine is also involved in the formation of 3-phenylindole by flash pyrolysis of l,5-diphenyl-l,2,3-triazole such an intermediate is not required, however, for the formation of the same product from 1,4-diphenyl-1,2,3-triazole (Scheme 14).75... [Pg.253]

Annular prototropy is not of great importance for small heterocycles. However, it should be mentioned that 1-azirine (2) is much more stable than its antiaromatic 2-isomer (3). By analogy, antiaromaticity is certainly a key factor determing instability of lH-azepines which have never been observed. Thus, demethoxycarbonylation of methyl-3,6-di-r-butylazepine-l-carboxylate (46) by DBU gives a mixture of the corresponding 2H-, 3H-, and 4//-azepines in the approximate ratio 13 56 1 (Scheme 9) (94JCS(P1)1753). The distribution of the azepine isomers is proportional to their relative thermal stabilities as they interconvert via allowed 1,5-hydrogen shifts. [Pg.162]

H-Azirin 2-(2,4-Dinitro-phenyl)-3-methyl- E16c, 323 (aus N-Sulfonyloxy-amidinen) lH-U-Benzodiazcpin 2,5-Dioxo-7-nitro-2,3,4,5-tetrahydro- E16d, 287 (Nitrierung)... [Pg.584]

Reports of pericyclic cyloadditions to other azepine systems are rare. Addition to the diene system of 6,7-dihydro-lH-azepines occurs readily with DMAD (72CPB1740) and with N-phenylmaleimide <73JA7320>. The 5,5a-dihydro-3-benzazepin-2-one (157), a suspected but non-isolable intermediate in the formation of l,2,4,5-tetrahydro-3H-3-benzazepine-2,4-diones by photoaddition of diphenylketen to amino-2i/-azirines, has been trapped in the photolysate by N-phenyl-l,3,4-triazoline-2,4-dione as the [4+2]ir adduct (158). Its structure was confirmed by X-ray analysis (80JOC2951). [Pg.522]

Die Photoumlagerung von lH-Pyrazolen bei 254-300 nm fiihrt gewohnlich in geringer Aus-beute zu Imidazolen (Bd. E8c, S.82)2355 2358 2361,2361a. Als Zwischenstufen der Reaktion werden Azirine bzw. 3-Amino-acrylnitrile2360 2360a b angcnommen (s.Lit.2359). [Pg.710]

IH-AzIrine, dihjrdro- DUiydro-lH-azlrlne Dimelhyl> neunlne Ethylimine... [Pg.221]


See other pages where LH-Azirine is mentioned: [Pg.157]    [Pg.33]    [Pg.97]    [Pg.1631]    [Pg.253]    [Pg.29]    [Pg.270]    [Pg.157]    [Pg.33]    [Pg.97]    [Pg.1631]    [Pg.253]    [Pg.29]    [Pg.270]    [Pg.79]    [Pg.4]    [Pg.272]    [Pg.133]    [Pg.282]    [Pg.91]   
See also in sourсe #XX -- [ Pg.2 ]




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Azirine

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