39889-69-5Relevant articles and documents
Ultrafast UV-Vis and IR studies of p-biphenylyl acetyl and carbomethoxy carbenes
Wang, Jin,Burdzinski, Gotard,Kubicki, Jacek,Platz, Matthew S.
, p. 11195 - 11209 (2008)
The photochemistry of a p-biphenylyl diazo ester (BpCN2CO 2CH3) and diazo ketone (BpCN2COCH3) were studied by ultrafast time-resolved UV-vis and IR spectroscopies. The excited states of these diazo compounds were detected and found to decay with lifetimes of less than 300 fs. The diazo ester produces singlet carbene with greater quantum efficiency than the ketone analogue due to competing Wolff rearrangement (WR) in the excited state of the diazo ketone. Carbene BpCCO 2CH3 has a singlet-triplet gap that is close to zero in cyclohexane, but the triplet is the ground state. The two spin states are in rapid equilibrium in this solvent relative to reaction with cyclohexane. There is (for a carbene) a slow rate of singlet to triplet intersystem crossing (isc) in this solvent because the orthogonal singlet must rotate to a higher energy orientation prior to isc. In acetonitrile and in dichloromethane BpCCO 2CH3 has a singlet ground state. Ketocarbene BpCCOCH 3 has a singlet ground state in cyclohexane, in dichloromethane, and in acetonitrile and decays by WR to form a ketene detected by ultrafast IR spectroscopy in these solvents. Ketocarbenes have more stable singlet states, relative to carbene esters, because of the superior conjugation of the filled hybrid orbital of the carbene with the π system of the carbonyl group, the same factor that makes methyl ketones more acidic than the analogous esters. The rate of WR of BpCCOCH3 is faster in cyclohexane than in dichloromethane and acetonitrile because of intimate solute-solvent interactions between the empty p orbital of the carbene and nonbonding electron pairs of heteroatoms of the solvent. These interactions stabilize the carbene and retard the rate of WR.
Base-catalyzed deuterium and tritium labelling of 1-biphenyl-4-ylpropane-1, 2-dione and deuteration of aryl methyl ketones
Berthelette, Carl,Scheigetz, John
, p. 891 - 894 (2004)
A synthesis and a base-catalyzed exchange reaction was developed under mild conditions to deuterate and subsequently tritiate the methyl group of the base sensitive diketone 1-biphenyl-4-ylpropane-1,2-dione depicted in Figure 1. Using Et3N as b
CEPHALOSPORIN CIPROFLOXACIN HYBRID COMPOUNDS
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Page/Page column 35; 39; 41, (2020/06/05)
A compound of formula (Ia) and related aspects.
N-monoarylacetothioureas as potent urease inhibitors: synthesis, SAR, and biological evaluation
Fang, Hai-Lian,He, Jie-Ling,Li, Wei-Yi,Liu, Shan-Shan,Ni, Wei-Wei,Pan, Xing-Ming,Xiao, Zhu-Ping,Ye, Ya-Xi,Yi, Juan,Zhou, Mi,Zhou, Tian-Li,Zhu, Hai-Liang
, p. 404 - 413 (2020/01/03)
A urease inhibitor with good in vivo profile is considered as an alternative agent for treating infections caused by urease-producing bacteria such as Helicobacter pylori. Here, we report a series of N-monosubstituted thioureas, which act as effective urease inhibitors with very low cytotoxicity. One compound (b19) was evaluated in detail and shows promising features for further development as an agent to treat H. pylori caused diseases. Excellent values for the inhibition of b19 against both extracted urease and urease in intact cell were observed, which shows IC50 values of 0.16 ± 0.05 and 3.86 ± 0.10 μM, being 170- and 44-fold more potent than the clinically used drug AHA, respectively. Docking simulations suggested that the monosubstituted thiourea moiety penetrates urea binding site. In addition, b19 is a rapid and reversible urease inhibitor, and displays nM affinity to urease with very slow dissociation (koff=1.60 × 10?3 s?1) from the catalytic domain.
