4388-29-8Relevant academic research and scientific papers
Formation and thermal decomposition of adducts of phthalimidonitrene with spiro(1-pyrazolinecyclopropanes)
Tomilov,Kostyuchenko,Shulishov,Averkiev,Antipin,Nefedov
, p. 1316 - 1322 (2007/10/03)
Oxidation of N-aminophthalimide with lead tetraacetate in the presence of spiro(1-pyrazolinecyclopropanes) at temperature from -20 °C to -30 °C resulted in the formal generation of phthalimidonitrene followed by its addition at the N=N bond of the pyrazoline ring to form 5(3)-substituted N-{spiro[1-pyrazolinio-3(5),1′-cyclopropane]}-N-phthalimidoamides (azimines), whose regioisomeric compositions were determined to a large extent by the nature of the substitueras in the pyrazoline ring. The structures of phthalimidoazimines were established based on the NMR spectra and X-ray diffraction data. Thermal conversions of the resulting adducts, which proceeded either with retention or with opening of the spiro-fused cyclopropane ring, were studied.
Free Radical Reactions of N-Heterocyclic Compounds, VI. - Radical Reactions of Cyclic 2,2-Diacyl-1-arylhydrazyls. - A New N-N Bond Cleavage Reaction
Schulz, Manfred,Kluge, Ralph,Willscher, Sabine
, p. 671 - 678 (2007/10/02)
Diacylhydrazyl radicals 5 are generated from N-(phenylamino)dicarboximides 1, 2a, b, 3a-f, and 4 by oxidation with different oxidants.The intermediates 5 react in two ways depending on the substituents in the anilino group.Dimerization of the hydrazyl radikals 5 to stable tetrazanes 8 is favoured by acceptor substituents in the Ar group.N-N bond dissoziation (α-decomposition) of the hydrazyl radicals 5 is favoured by donor substituents in the phenyl ring of the anilino group.The fragments of such reactions are imide radicals 22 and phenylnitrenes 23.The formation of these fragmentation products is proven by analysis of the reaction products.The formation of benzoxazole (25) (15percent yield) is an evidence for an intramolecular insertion reaction of the o-methoxyphenylnitrene, generated by oxidation of 3e.The hydrazyl radicals 5 are also trapped by the stable free radical 2,4,6-tri-tert-butylphenoxyl (9).The thermal decomposition of the isolated radical adducts was studied.
1-Aryl- und 1-Alkyl-2-phthalimido-diazen-1-oxide, diacylierte Vertreter von trisubstituierten Triazen-1-oxiden: Bildung, Eigenschaften, Stereoisomerisierung und Fragmentierung
Hoesch, Lienhard,Koppel, Bruno
, p. 864 - 889 (2007/10/02)
Oxidatively generated phthalimido-nitrene (1) reacts with nitrosobenzene (8a), p-nitrosotoluene (8b), o-nitrosotoluene (8c), p-dimethylamino-nitrosobenzene (8d), p-methoxycarbonyl-nitrosobenzene (8e), 1,1-dimethyl-1-nitrosoethane (8f) and nitrosocyclohexane (8g) to give the respective 1-substituted (Z)-2-phthalimidodiazene-1-oxides 14a-g.The constitution of the 2-imidodiazene-1-oxides 14 is deduced from their spectroscopic properties.The UV. spectra of 14a-e are similar with those of the corresponding nitrobenzenes 18, thus supporting the concept of comparibility of the phthalimido-N group with an O-atom and indicating that the phthalimido group is not in conjugation with the diazene-oxide function.This is in contrast to situation in the non-acylated trisubstituted triazene-1-oxides 12, where conjugation is extended over the chain of all three N-atoms as exhibited by the UV. spectra of (Z)-1,3,3-triphenyl-, (Z)-3,3-dimethyl-1-phenyl-, (Z)-3-methyl-1,3-diphenyl-, (Z)-1-(1,1-dimethylethyl)-3,3-diphenyl-, and (Z)-1-(1,1-dimethylethyl)-3,3-dimethyltriazene-1-oxide (12a-e).These triazene-1-oxides are formed by the reaction of 1,1-disubstituted hydrazines 11 with three mol-equiv. of nitroso compounds 8 or from equimolar amounts of 11 and 8 in the presence of mercury oxide.Over 90percent of 1,2-diphenyldiazeneoxide (19, R=C6H5) are isolated by the reaction 11+3 8a.Possible mechanisms of the reaction of 11 with 8, and of the formation of 12 via triazanols D and of 19 (R=C6H5) via N-phenyl-hydroxylamine (20, R=C6H5) are given in Scheme 6 (in the latter case with experimental evidence).An independent synthesis of 12c confirms the constitutional assignment for 12.The (Z)-configuration of the 2-imidodiazene-1-oxides 14 follows from comparison of their UV. and 1H-NMR. spectra with those of the corresponding (E)-isomers 31, obtained by irradiation of 14 above 300 nm.Only (E)-1-phenyl- and (E)-1-(p-tolyl)-2-phthalimido-diazene-1-oxide (31a and 31b, respectively) could be isolated.The (E)-isomer 31a isomerizes back thermally to its thermodinamically more stable isomer 14a.This reaction is accompanied by thermal fragmentation into phthalimido-phthalimide (35) and phthalimide (36).The same products, together with N-phenylphthalimide (38), are also obtained by thermolysis of 14a in boiling decaline.A radical mechanism is proposed for this reaction.Irradiation of 14 below 300 nm splits the molecule into 1 and the corresponding nitroso compound 8.The nitrene 1 can be trapped by cyclohexene to give 7-phthalimido-7-azabicycloheptane (32) in 60percent yield.In the absence of a trapping agent, the nitrene 1 furnishes 35 (18percent) and 36 (35percent), presumably via its dimer 1,4-bis(phthaloyl)-2-tetrazene (33), which is photolytically cleaved to nitrogen and two molecules of phthalimido radical (34), the precursor of 35 and 36.Hydrazinolyses of 12a, 12b and 12f generates the corresponding N-substituted hydroxylamines 20 (R=C6H5 or p-CH3C6H4 or (CH3)3C, resp.) in more than 95percent yield.A mechanism for the formation of 20 is proposed.
