73607-90-6Relevant academic research and scientific papers
Reversible Generation of Labile Secondary Carbocations from Alcohols in the Nanospace of H-Mordenite and Their Long-Lasting Preservation at Ambient Temperature
Masui, Yoichi,Hattori, Taiki,Onaka, Makoto
, p. 8612 - 8620 (2017)
Secondary carbocations are rarely observed spectrometrically for prolonged durations at ambient temperatures because of their instability. In this study, when 4,4′-difluorobenzhydrol (1) was mixed with H-mordenite (H-Mor), the 4,4′-difluorodiphenylmethyl cation (2) was generated as the main product, identified by UV-vis and 13C-MAS NMR spectroscopies, and was preserved for over 1 week at ambient temperature. Surprisingly, the polymerization and disproportionation of 1 barely proceeded within the micropores of H-Mor. However, these side reactions prevailed in TfOH and formation of 2 was not observed. Preservation of other secondary carbocations from benzhydrol, 4,4′-dichlorobenzhydrol, and 9-fluorenol was also realized in H-Mor. It was confirmed that the generation of 2 from 1 was controlled by thermodynamic equilibrium rather than kinetic regulations. The equilibrium between 2 and 1 was accompanied by reversible chromism, which could be easily controlled by altering the moisture content in H-Mor. Moreover, novel insights into specific acid catalysis in zeolites densely populated with acid sites on the inner surface of micropores are described herein.
Atorvastatin, an HMG-CoA reductase inhibitor and effective lipid-regulating agent. Part III. Syntheses of [2H5]-, [13C8], and [13C7,15N]atorvastatin and their application in metabolic and pharmacokinetic studies
Woo, Peter W. K.,Hartman, Jon,Hicks, James,Hayes, Roger
, p. 135 - 145 (2007/10/03)
Three stable-isotope-labeled forms of atorvastatin, [2H5], [13C8], and [13C7,15N], were synthesized. They were utilized primarily for metabolic mapping and pharmacokinetic studies of bioequivalence. Analytical assays were performed by using LC/MS/MS methodologies.
Transition-State Polarization in Cleavage of C-C Bonds in Radical Anions
Maslak, Przemyslaw,Narvaez, Javier N.,Kula, Jozef,Malinski, David S.
, p. 4550 - 4559 (2007/10/02)
The substituent effect on the rate of C-C bond cleavage in radical anions of 1-(4-nitrophenyl)-2-(substituted-phenyl)-1,1,2,2-tetraethylethanes has been explored.The data provide evidence for two distinctive modes of bond scission.One mode is characterized by a significant negative charge transfer across the scissile bond in the transition state.Such polarization of the transition state is in contradiction to the prediction based on the fragments' stability.The second mode, dominant in cases where the charge shift leads to negative charge accumulation on an already electron-rich fragment, involves a ?* radical anion.Both modes point to a general kinetic preference for a cleavage of radical anions that allows for charge delocalization across the scissile bond.
