1379326-22-3Relevant academic research and scientific papers
Synthesis of 4H-1,3-Benzoxazines via Metal- and Oxidizing Reagent-Free Aromatic C-H Oxygenation
Xu, Fan,Qian, Xiang-Yang,Li, Yan-Jie,Xu, Hai-Chao
supporting information, p. 6332 - 6335 (2017/12/08)
An unprecedented electrochemical aromatic C-H oxygenation reaction for the synthesis of 4H-1,3-benzoxazines from easily available N-benzylamides is reported. These oxidative cyclization reactions proceed in a transition metal- and oxidizing reagent-free fashion and produce H2 as only theoretical byproduct. Adapting the C-H oxygenation reaction in an electrochemical microreactor has been demonstrated.
Solvolysis of 2-chloro-2(3,4-disubstituted) phenylpropanes: Validity of Hammett-Brown σ+ constants in assessing additive effects of substituents
Taha, Ahmed A.
scheme or table, p. 514 - 523 (2012/07/28)
The objective of this study is to test the suitability of the extended Hammett-Brown equation, log (kXX/kHH) = ρ+∑σ+, in depicting satisfactorily additive effects of electronegative atom-bearing substituents, which are known to possess diverse and multicomponent influences on the side chain reactions of polysubstituted benzenes. The equation has been used to correlate, for the first time, the additive effect of substituents in the specific rates of solvolysis of 2-chloro-2-phenylpropanes (3b-3f) having 3-F,4-Me, 3-Br,4-Me, 3-I,4-Me, 3-Me,4-Me, or 3-MeO,4-Me substituents. The rates were determined titrimetrically at 288, 298, and 308 K using 90% aqueous acetone as solvent. Measured additive effects of these substituents on the solvolysis rate and activation parameters of the parent cumyl chloride (2-chloro-2-phenylpropane) are found to be well correlated using the equation given above. Plots of log (kXX/k HH) of 3b-3f together with mainly di-, but also tri- and mono-substituted cumyl chlorides from previous studies against ∑σ+ give a linear correlation coefficient of 0.990 as a measure of the validity of the equation to depict such systems. The halogen substituents' extent of conformity with additivity reflected in their relative (kobsd/kcalcd) rate ratios is found to correlate with the steric size of substituents. Plots of rate ratios against Taft's steric factor of each halogen give a linear correlation coefficient of 0.994 for the 3-halo substituents. The 3,4-dimethyl substituents' relative rate ratio of 1.03 shows excellent additivity, whereas the 3-methoxy-4-methyl ratio of 1.43 shows the methoxy group to be far less deactivating than predicted. Similar trends were found for the free energy of activation (δG? - δG 0?) differences, which correlated linearly with a coefficient of 0.983 with Taft's steric factor of halogen atoms.
