Kinetic study of the thermal decomposition of (Z)-N-tert-butyl-.alpha.-phenylnitrone

Increasing the index of covalent oxygen bonding at nitrogen attached to carbon

“…Although further oxidation of the amidyls 343, 344, and 345 was not reported, the radicals dimerized into hydrazine derivatives and cyclized onto the nearby aromatic ring. 261 These properties together with the ease of dehydrogenation tend to support an earlier isolated report of a peroxide oxidation of a sulfonamide (346) into the N-hydroxy sulfonamide (347) which upon hydrolysis gave a-(hydroxylamino)pyridine (348; eq 256) Oxidation of mesidine (349) with Fremy's salt and basecatalyzed oxygenation (section V.D.1) of 4-substituted 2,6-difert-butylanilines (351) in toluene or tetrahydrofuran stopped at the nitroso stage (eq 257,258). 264 An inhibition to further oxidation at nitrogen was attributed to steric factors.…”

N-alkenyl nitrone dipolar cycloaddition routes to piperidines and indolizidines. Part 7. Hydroxylamine–alkyne cyclisations. Formation of cyclic nitrones and application to the synthesis of the proposed structure for (±)-acacialactam

“…The combined organic layers were dried (MgSO,) and the solvent was evaporated under reduced pressure. The compound was purified by flash chromatography on silica, eluting with hexane-ethyl acetate (19 : 1) to give the silylated alkyne 9 as a colourless oil (1.36 4); m/z (EI) 211 (39%), 127 (loo), 99 (54), 83 (12), 73 (24) and 55 (27); m/z (CI) 267 (MH',5773,223 (loo), 21 1 (52), 151 (23), 133 (21), 127 (loo), 117 (43), 99 (50) and 90 (100) [Found: MH' 267.1780 (CI). C, ,H,,O,Si requires MH 267.17801.…”

“…C,,H,, NO requires C,72.9;H,10.6; N, 7.7%); v,,,(CCl,)/cm-' 361 0s (0-H) and 3260brm (0-H); 6,( 250MHz; CDCl,) 2.78-2.62 (2 H, m, CHN), 2.16-2.09 (2 H, m, CH,C=C), 1.98-1.77 (3 H, m), 1.75 (3 H, t, J2.6, C S M e ) , 1. 53-1.21 (5 H, m) and 1 .18 (3 H,d,J 6.2,CHMe); 6,-(100 MHz; CDCl,) 79.1 (s), 75.6 (s), 67.9 (d), 63.6 (d), 33.5 (t), 27.2 (t), 26.2 (t), 25.3 (t), 19.0 (q), 18.8 (t) and 3.5 (9); m/z (EI) 164 (13%), 126 (40), 100 (1 00), 82 (1 7), 79 (1 3), 77 (1 l), 67 (24), 53 (28) and 41 (35); m/z (CI) 182 (MH+, 100%) and 100 (14) [Found: M + 181.1467 (EI). C11H19N0 requires M 181.14671; and the transpyrrolidine 21 as a pale yellow oil (68 mg, 58%), R, 0.15, 1 : 1 ether-hexane (Found: C,73.0;H,10.6;N,7.6.…”

Radical Formation in Sugar-Derived Acetals under Solvent-Free Conditions

“…The EPR spectra of the adducts are characterized by the isotropic g-value ( g iso ), isotropic hyperfine couplings of the nitroxide nitrogen ( A N iso ), the α -proton ( A H α iso ), and in some cases also other protons, which are dependent on the spin-trapped radical. The mixtures were only heated to 140 °C because the concerted thermal decomposition of PBN at this temperature is still relatively slow [ 18 ]. A clear room temperature EPR signal was observed for the heated GalXH/PBN mixture that was subsequently dissolved in toluene, while, under the same conditions, no signals were observed for the heated GalXMe/PBN mixture or PBN alone ( Figure 2 ).…”