4388-29-8Relevant articles and documents
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.
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.
