92241-75-3Relevant academic research and scientific papers
Design of a hyperpolarized 15N NMR probe that induces a large chemical-shift change upon binding of calcium ions
Hata, Ryunosuke,Nonaka, Hiroshi,Takakusagi, Yoichi,Ichikawa, Kazuhiro,Sando, Shinsuke
supporting information, p. 12290 - 12292 (2015/07/27)
Ca2+ is a fundamental metal ion for physiological functioning. Therefore, molecular probes for Ca2+ analysis are required. Recently, a hyperpolarized NMR probe has emerged as a promising tool. Here, we report a new design of a hyperp
15N-CIDNP during Photonitration of Phenol with Tetranitromethane and Reactions with Nitric and Nitrous Acid
Lehnig, Manfred,Schürmann, Klaus
, p. 913 - 918 (2007/10/03)
During the irradiation of phenol (1) with 15N-enriched tetranitromethane in acetonitrile, and during the reaction of 1 with 15N-enriched nitric acid and nitrous acid, emission due to the nitration products o- and p-nitrophenol (2a, 2b) is observed in the 15N-NMR spectra. The CIDNP effects are built up by radical pairs formed by the encounters of the radicals NO2? and 1+? or PhO?. During the reaction of 1 with nitrous acid, 2b is formed, in part due to a non-radical reaction, via oxidation of p-nitrosophenol (3).
The Mechanism of Nitration by 4-Methyl-4-nitro-2,3,5,6-tetrabromocyclohexa-2,5-dienone
Coombes, Robert G.,Ridd, John H.
, p. 174 - 175 (2007/10/02)
Nitration of phenol by 4-methyl-4-nitro-2,3,5,6-tetrabromocyclohexa-2,5-dienone in diethyl ether is a radical process involving reaction between the phenoxyl radical and NO2 radical that has escaped from a radical pair in which it was formed by homolytic
Benzidine Rearrangements. 19. The Concerted Nature of the One-Proton Rearrangement of 2,2'-Dimethoxyhydrazobenzene
Shine, Henry J.,Park, Koon Ha,Brownawell, Marilyn L.,Filippo, Joseph San
, p. 7077 - 7082 (2007/10/02)
Kinetic isotope effects (KIE) in the acid-catalyzed, one-proton rearrangement of 2,2'-dimethoxyhydrazobenzene (1) into 3,3'-dimethoxybenzidine (2) have been measured.Nitrogen KIE were determined on the bis(trifluoroacetyl) derivative of 2 which was isolated from low and 100percent conversions of mixtures of 1 and 1 under kinetic conditions.The ratio of masses M(438)/M(436) as determined by whole-ion mass spectrometric techniques led to the result k(14N)/k(15N)=1.0289 (for two nitrogens).Similar measurements on the derivative of 2 isolated from conversions of mixtures of 1 and 1 led to the result k(12C)/k(13C)=1.0286 (for two carbons).These results show that the formation of 2 is a concerted process and, thus, that the acid-cytylyzed rearrangement of 1 is a 5,5-sigmatropic shift.Rearrangement via a ?-complex intermediate or a solvent-caged, radical/radical-ion pair is excluded.That bonding in the 4,4' positions of 1 is part of the rate-determining step in this rearrangement was confirmed by measurement of an inverse secondary deuterium KIE (kH/kD=0.929 for two deuteriums).This result was obtained from ratios of M(244)/M(242) which were measured on 2,2'-dimethoxyazobenzene (3), obtained by oxidizing the hydrazo substrate remaining after high conversions of mixtures of 1 and 1.
