4-Nitrosoquinoline 1-oxide

The title compound has been synthesized by the oxidation of 4-hydroxylaminoquinoline 1-oxide with silver carbonate on celite. Some of its chemical properties have been studied and compared with those of 4-nitrosopyridine 1-oxide. Its mass spectrum and those of related compounds are discussed.     

The photochemistry of 4-azidopyridine-1-oxide

Laser flash photolysis of 4-azidopyridine-1-oxide at 266 or 308 nm yields triplet 4-nitrenopyridine-1-oxide as the dominant reactive intermediate species, with k(ISC) of approximately 2 x 10(7) s(-1). No evidence of products arising from the singlet nitrene was observed, indicating a slow rate of cyclization to the benzazirine and didehydroazepine species. The slow rate of cyclization is postulated to be due to the aminoxyl-like electronic configuration of this species, which withdraws spin density from sites for potential cyclization.     

Lanthanide perchlorate complexes of 4-nitroquinoline-1-oxide and 5-nitroisoquinoline-2-oxide

Novel complexes of lanthanide perchlorates with 4-nitroquinoline-1-oxide (NQNO) and 5-nitroisoquinoline-2-oxide (NIQNO) have been prepared and characterized. The complexes have the general formulaeLn(NQNO)₈(ClO₄)₃ (whereLn=La-Nd), Ln(NQNO)₇(ClO₄)₃ (whereLn=Gd-Yb),Ln(NIQNO)₉(ClO₄)₃ (whereLn=La-Nd), andLn(NIQNO)₇(ClO₄)₃ (whereLn=Gd-Yb). The IR, proton NMR spectral data indicate the coordination of the N—O group of the ligands to he lanthanide ions.de|Es wurden neue Komplexe von Lanthanidperchloraten mit 4-Nitrochinolin-1-oxid (NQNO) und 5-Nitroisochinolin-2-oxid (NIQNO) dargestellt und charakterisiert. Die Komplexe haben die allgemeinen FormelnLn(NQNO)₈(ClO₄)₃ (mitLn=La-Nd),Ln(NQNO)₇(ClO₄)₃ (mitLn=Gd-Yb),Ln(NIQNO)₉(ClO₄)₃ (mitLn=La-Nd) undLn(NIQNO)₇(ClO₄)₃ (mitLn=Gd-Yb). Die IR- und NMR-Daten zeigen die Koordination der N—O-Gruppe der Liganden zum Lanthanidenion an.

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Lanthanid-Perchlorat-Komplexe von 4-Nitrochinolin-1-oxid und 5-Nitroisochinolin-2-oxid

     

Computational study of conformations and of sulfinyl oxygen-induced pentacoordination at silicon in 4-chloro-4-silathiacyclohexane 1-oxide and 4,4-dichloro-4-silathiacyclohexane 1-oxide

Second-order Møller-Plesset theory (MP2) and density functional theory (B3LYP) with the 6-311G(d,p) and 6-311+G(d,p) basis sets have been used to calculate the equilibrium geometries and relative energies of the chair, twist, and boat conformations of 4-chloro-4-silathiacyclohexane 1-oxide and 4,4-dichloro-4-silathiacyclohexane 1-oxide. The chair conformers of the axial sulfoxides are lower in energy than the chair conformers of the corresponding equatorial sulfoxides. MP2/6-311+G(d,p) predicted the chair conformer of axial trans-4-chloro-4-silathiacyclohexane 1-oxide (4a) to be 6.12, 0.44, and 0.45 kcal/mol, respectively, more stable than the corresponding 1,4-twist (4b), 2,5-twist (4c) and 1,4-boat (4d) conformers and 6.93 kcal/mol more stable than the 2,5-boat transition state ([4e]^‡). Structures 4c and 4d are stabilized by intramolecular coordination of the sulfinyl oxygen with silicon that results in trigonal bipyramidal geometry at silicon. The 1,4-boat conformer (7d) of axial 4,4-dichloro-4-silathiacyclohexane 1-oxide is also stabilized by transannular coordination of the sulfinyl oxygen with silicon. The energy difference (E_rel = 4.23 kcal/mol) between the chair conformer (7a) and 7d is larger than that between 4a and 4d. The relatively lower stability of the 1,4-boat conformer (7d) of axial 4,4-dichloro-4-silathiacyclohexane 1-oxide (7a) may be due to repulsive interactions of the axial halogen and sulfinyl oxygen atoms. The relative energies and structures of the conformers and transition states of cis- and trans-4-chloro-4-silathiacyclohexane 1-oxide and 4,4-dichloro-4-silathiacyclohexane 1-oxide are discussed in terms of hyperconjugative interactions, orbital interactions, nonbonded interactions, and intramolecular sulfinyl oxygen-silicon coordination.     

4-硝基氮氧化吡啶在酸性水溶液中的电化学还原历程探讨

综述了4-硝基氮氧化吡啶在酸性溶液中的电化学还原反应历程。参考文献31篇。     

Free radicals in the electrochemical reduction of 1,2-dihydro-3-nitropyridine derivatives

The formation of primary radical anions of N-substituted 1, 2-dihydro-3-nitropyridines was confirmed by the ESR method under conditions of electrochemical generation of free radicals, and their structure was established. The causes of the different ability of 1,2- and 1,4-dihydro-3-nitropyridines to form free radicals during electrochemical reduction that are stable enough to be studied by the ESR method are examined.Latvian Institute of Organic Synthesis, Riga LV-1006.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1222–1227, September, 1996. Original article submitted May 20, 1996.