852026-60-9Relevant academic research and scientific papers
Effect of substituent on regioselectivity and reaction mechanism in aminolysis of 2,4-dinitrophenyl X-substituted benzenesulfonates
Um, Ik-Hwan,Hong, Jin-Young,Seok, Jin-Ah
, p. 1438 - 1444 (2007/10/03)
(Chemical Equation Presented) We report on a kinetic study for the nucleophilic substitution reactions of 2,4-dinitrophenyl X-substituted benzensulfonates (X = 4-MeO, 1a, and X = 4-NO2, 1c) with a series of primary amines in 80 mol % H2O/20 mol % DMSO at 25.0 °C. The reactions proceed through S-O and C-O bond fission pathways competitively. The fraction of the S-O bond fission increases as the attaching amine becomes more basic and the substituent X changes from 4-MeO to 4-NO2, indicating that the regioselectivity is governed by the electronic nature of the substituent X as well as the basicity of amines. The S-O bond fission has been suggested to proceed through an addition intermediate with a change in the rate-determining step (RDS) at pK°a = 8.9 ± 0.1. The electronic nature of the substituent X influences kNS-O and k1 values, but not the k2/k-1 ratios and the pK°a value significantly. Stabilization of the ground state (GS) through resonance interaction between the electron-donating substituent and the electrophilic center has been suggested to be responsible for the decreased reactivity of 1a compared to 1c. The second-order rate constants for the C-O bond fission exhibit no correlation with the electronic nature of the substituent X. The distance effect and the nature of the reaction mechanism have been suggested to be responsible for the absence of the correlation.
Discovery of CGS 27023A, a non, peptidic, potent, and orally active stromelysin inhibitor that blocks cartilage degradation in rabbits
MacPherson, Lawrence J.,Bayburt, Erol K.,Capparelli, Michael P.,Carroll, Brian J.,Goldstein, Robert,Justice, Michael R.,Zhu, Lijuan,Hu, Shou-Ih,Melton, Richard A.,Fryer, Lynn,Goldberg, Ron L.,Doughty, John R.,Spirito, Salvatore,Blancuzzi, Vincent,Wilson, Doug,O'Byrne, Elizabeth M.,Ganu, Vishwas,Parker, David T.
, p. 2525 - 2532 (2007/10/03)
Structure-activity relationships of a lead hydroxamic acid inhibitor of recombinant human stromelysin were systematically defined by taking advantage of a concise synthesis that allowed diverse functionality to be explored at each position in a template. An ex vivo rat model and an in vivo rabbit model of stromelysin-induced cartilage degradation were used to further optimize these analogs for oral activity and duration of action. The culmination of these modifications resulted in CGS 27023A, a potent, orally active stromelysin inhibitor that blocks the erosion of cartilage matrix.
