22776-71-2Relevant articles and documents
Oxidative C-H bond functionalization and ring expansion with TMSCHN2: A copper(I)-catalyzed approach to dibenzoxepines and dibenzoazepines
Stopka, Tobias,Marzo, Leyre,Zurro, Mercedes,Janich, Simon,Würthwein, Ernst-Ulrich,Daniliuc, Constantin G.,Alemán, José,Manche?o, Olga García
supporting information, p. 5049 - 5053 (2015/04/27)
Tricyclic dibenzoxepines and dibenzazepines are important therapeutic agents for the pharmaceutical industry and academic research. However, their syntheses are generally rather tedious, requiring several steps that involve a Wagner-Meerwein-type rearrangement under harsh conditions. Herein, we present the first copper(I)-catalyzed oxidative C-H bond functionalization and ring expansion with TMSCHN2 to yield these important derivatives in a facile and straightforward way. Cut a long story short: Tricyclic dibenzoxepines and dibenzazepines are important therapeutic agents for pharmaceuticals, but their syntheses are generally rather tedious. A copper(I)-catalyzed oxidative C-H bond functionalization and ring expansion sequence with TMSCHN2 has been developed to yield these important derivatives in a facile and straightforward way.
Uncatalyzed Transfer Hydrogenation of α-Methylstyrene by 9,10-Dihydroacridine and N-Methyl-9,10-dihydroacridine
Friebolin, Heike,Ruechardt, Christoph
, p. 1339 - 1342 (2007/10/02)
Hydrogen is transferred from acridane (1c) and N-methylacridane (1d) to α-methl-styrene (2) in a bimolecular uncatalyzed reaction at 260-300 deg C.On the basis of the activation parameters (for 1c: ΔH(excit) = 29.0 kcal/mol, ΔS(excit) = -23.5 e.u. in triglyme) the kinetic isotope effect (kH/kD = 2.0, in triglyme at 300 deg C) as well as the small solvent effects and from the observation of an EPR signal of N-methylhydroacridyl radicals a three-step radical mechanism is proposed which is initiated by a retrodisproportionation between 1 and 2. - Key Words: Hydrogen transfer / Molecule-induced formation of radicals / Retrodisproportionation / Acridines, dihydro-
Electron-transfer oxidation of 9-substituted 10-methyl-9,10-dihydroacridines. Cleavage of the C-H vs C-C bond of the radical cations
Fukuzumi, Shonichi,Tokuda, Yoshihiro,Kitano, Toshiaki,Okamoto, Toshihiko,Otera, Junzo
, p. 8960 - 8968 (2007/10/02)
Electron-transfer oxidation of various 9-substituted 10-methyl-9,10-dihydroacridines (AcrHR) by Fe(ClO4)3 and [Fe(phen)3](PF6)3 (phen = 1,10-phenanthroline) results in cleavage of the C(9)-H or C(9)-C bond of AcrHR?+ depending on the substituent R. Transient electronic absorption spectra as well as electron spin resonance (ESR) spectra of AcrHR?+ have been detected by using a stopped-flow spectrophotometer and a rapid mixing flow ESR technique, respectively. The hyperfine splitting constants (hfs) are determined by comparing the observed ESR spectra with those from the computer simulation. Comparison of the hfs values with those expected from the molecular orbital calculations indicates the structural change of AcrHR?+ with the substituent R, which is reflected in the selectivity of the C-H vs C-C bond cleavage of AcrHR?+ depending on the substituent R. The decay rates of AcrHR?+ obey the mixture of first-order and second-order kinetics due to the deprotonation (or the C-C bond cleavage) and disproportionation reactions, respectively. Both the first-order and bimolecular second-order decay rate constants of AcrHR?+ are reported. The first-order decay rate constant for the deprotonation of AcrHR?+ by the C-H bond cleavage decreases with the substitution in order R = primary > secondary > tertiary alkyl groups, while the first-order decay due to the C-C bond cleavage becomes dominant with tertiary alkyl groups. The one-electron oxidation potentials of various AcrHR have been determined directly by applying fast cyclic voltammetry. The pKa values of AcrHR?+ (R = H and Me) have also been evaluated by analyzing the dependence of the first-order deprotonation rate constants on the concentrations of HClO4.
