N photolysis

N.S. Allen, A. Chirinos-Padron, and J.H. Appleyard, Photo-stabilizing action of metal chelates in polypropylene. Part n. Photolysis versus photosensitized oxidation under monochromatic irradiation, Polym. Degrad. Stab. 1983, 5, 29—41. 

Noma Y Takigami H, Kajiwara N. Photolysis studies of technical Decabromodiphenyl ether (DecaBDE) and ethane (DeBDethane) in plastics under natural sunlight. Environ Sci Technol 2008 42 (12) 4404 09. 

Miyasaka H, Hagihara M, Okada T and Malaga N 1992 Femtoseoond laser photolysis studies on the oooling prooess of ohrysene in the vibrationally hot S., state in solution Chem. Phys. Lett. 188 259-64... 

The reactivity of the amino radical has not yet been investigated. Alkaline hypochlorite oxidation, known in the pyridine series to yield azo derivatives (155,156). and photolysis of N,N-dichloro derivatives, which may be obtained by action of sodium hypochlorite on amino derivatives in acidic medium (157). should provide interesting insight on this reactivitv. 

Ug2/)) (n 2p) (Tig 2p) ground electron configuration. Photolysis by radiation from the sun, at wavelengths below about 310 nm, produces O2 almost exclusively in the a state whereas a wavelength as low as 193nm produces about 23% of O2 in the b state. 

Irradiation of ethyleneimine (341,342) with light of short wavelength ia the gas phase has been carried out direcdy and with sensitization (343—349). Photolysis products found were hydrogen, nitrogen, ethylene, ammonium, saturated hydrocarbons (methane, ethane, propane, / -butane), and the dimer of the ethyleneimino radical. The nature and the amount of the reaction products is highly dependent on the conditions used. For example, the photoproducts identified ia a fast flow photoreactor iacluded hydrocyanic acid and acetonitrile (345), ia addition to those found ia a steady state system. The reaction of hydrogen radicals with ethyleneimine results ia the formation of hydrocyanic acid ia addition to methane (350). Important processes ia the photolysis of ethyleneimine are nitrene extmsion and homolysis of the N—H bond, as suggested and simulated by ab initio SCF calculations (351). The occurrence of ethyleneimine as an iatermediate ia the photolytic formation of hydrocyanic acid from acetylene and ammonia ia the atmosphere of the planet Jupiter has been postulated (352), but is disputed (353). 

The effects of uv radiation on V/-nitroso compounds depend on the pH and the medium. Under neutral conditions and ia the absence of radical scavengers, these compounds often appear chemically stable, although the E—Z equiUbrium, with respect to rotation around the N—N bond, can be affected (70). This apparent stabiUty is due to rapid recombination of aminyl radicals and nitric oxide [10102-43-9] formed duting photolysis. In the presence of radical scavengers nitrosamines decay rapidly (71). At lower pH, a variety of photoproducts are formed, including compounds attributed to photoelimination, photoreduction, and photo-oxidation (69). Low concentrations of most nitrosamines, even at neutral pH, can be eliminated by prolonged kradiation at 366 nm. This technique is used ki the identification of /V-nitrosamines that are present ki low concentrations ki complex mixtures (72). 

The pyrazole ring is resistant to oxidation and reduction. Only ozonolysis, electrolytic oxidations, or strong base can cause ring fission. On photolysis, pyrazoles undergo an unusual rearrangement to yield imidazoles via cleavage of the N —N2 bond, followed by cyclization of the radical iatermediate to azirine (27). 

There are various photochemical transformations of pyridazines, their corresponding benzo analogs, N-oxides and N-imides. Gas-phase photolysis of pyridazine affords nitrogen and vinylacetylene as the main products. Perfluoropyridazine gives first perfluoropyrazine, which isomerizes slowly into perfluoropyrimidine. 

Photolysis of 3-methyl-1,2-benzisoxazole in n-hexane/acetonitrile produced a salicyl-amide. In contrast, photolysis in acetonitrile/methanol (95 5) gave an iminoester which subsequently hydrolyzed to methyl salicylate (Scheme 11) (74HCA376). 

Methyl-l,2-benzisoxazol-3-one on photolysis yielded AC-methylbenzoxazole and N-methylsalicylamide (Scheme 15) <71DIS(B)4483, 71JOCIO88,77Ml4l6ii). 

Flash photolysis of a 4-enamino-5-one at 650 °C generated ethylnylamine, which was stable at -196 °C and its IR spectrum was examined. Warming caused tautomerization to N-phenylketenimine (Scheme 66) (80AG743). 

In contrast to the well-defined photochemical behavior of 1-azirines the thermal reactions of these compounds have been studied less thoroughly (68TL3499). The products formed on photolysis of azirines can best be rationalized in terms of an equilibration of the heterocyclic ring with a transient vinylnitrene. Thus, products formed from the thermolysis of azirines are generally consistent with C—N cleavage. For example, the vinylnitrene generated from the thermolysis of azirine (149) can be trapped with phosphines (72CCS6S). 

The isomerization of oxaziridines (1) to acid amides with migration of a substituent from C to N is a general reaction and is always observed when no other reactions predominate under the relatively harsh conditions (heating to above 150 °C or photolysis). Even then one can make acid amide formation the main reaction by working at 300 °C (57JA5739) and by dilution techniques. For example, caprolactam (63) is formed in 88% yield by flash pyrolysis of oxaziridine (52) at about 300 °C, whereas decomposition of (52) at lower temperatures gives almost no (63) (77JPR274). 

Direct proof of an oxaziridine intermediate was achieved in photolysis experiments in an organic glass at 77 K (80JA5643). Oxaziridine (75), formed by photolysis of A/-oxide (74) and evidenced by UV spectroscopy under the above conditions, decomposed at higher temperature to form the imino ether (76) by N—O bond cleavage and C -> O migration of an aryl group. 

Photolysis of phenacylamines (32) gives azetidin-3-ols (33) as minor products (66CC289). Higher and more consistent yields are obtained from photolyses of a-N-alkylamidoaceto-phenones (34), which gives N-tosylazetidines (35) in 74-95% yield (71JA2793). The key step... 

The first benzazetidine (243) was isolated from the photolysis of 3-phenyldihydroben-zotriazine (242) (66JA1580). Another route to benzazetidines involving formation of the N to aryl-C bond utilizes intramolecular nucleophilic substitution via aryne (287). It is not general, however, and is only satisfactory when R and/or are alkoxy groups. The reaction also fails for iV-alkylamines (78LA608). 

Isoxazolines bromination, 6, 78 chemical potentials, 6, 7 melting and boiling points, 6, 9 oxidation, 6, 37 photolysis, 6, 37-38 N-oxides... 

Pyridazine N-ethoxycarbonylimide photolysis, 3, 13 Pyridazine, 4-gJycosyloxy-rearrangement, 3, 15 Pyridazine, halo-applications, 3, 56 Pyridazine, hexahydro-, 3, 40 photoelectron spectra, 2, 20-21 Pyridazine, hydrazino-reductive cleavage, 3, 34 synthesis, 3, 35 Pyridazine, hydroxy-acidity, 3, 4 Pyridazine, 3-hydroxyl-oxide... 

S-N rearrangement, 3, 36 ionization constants, 3, 4 oxidation, 3, 37 quatemization, 3, 17 Pyridazine-3 (2 H) - thiones analysis, 3, 2 tautomerism, 3, 5 Pyridazinium betaine, 3-oxido-photolysis, 3, 11 Pyridazinium betaine, 5-oxido-photolysis, 3, 11 Pyridazinium dicyanomethylide photolysis, 3, 12... 

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