129716-12-7Relevant academic research and scientific papers
Hydrogen Atom Transfer vs. Electron Transfer in Iron(III) Porphyrin catalysed Benzylic Oxidations
Baciocchi, Enrico,Crescenzi, Manuela,Lanzalunga, Osvaldo
, p. 687 - 688 (1990)
The scope of hydrogen atom transfer and electron transfer mechanisms has been established for the benzylic oxidations of alkylaromatic compounds and benzyltrimethylsilanes induced by an iron(III) porphyrin complex.
Benzylimidazolines as h5-HT(1B/1D) serotonin receptor ligands: A structure-affinity investigation
Law, Ho,Dukat, Malgorzata,Teitler, Milt,Lee, David K. H.,Mazzocco, Lucia,Kamboj, Raj,Rampersad, Vik,Prisinzano, Thomas,Glennon, Richard A.
, p. 2243 - 2251 (2007/10/03)
Benzylimidazolines may represent a class of 5-HT(1D) ligands that has yet to be exploited. On the basis of a previous report that the 2- (substituted-benzyl)imidazoline α-adrenergic agonist oxymetazoline (8) binds with high affinity at calf brain 5-HT(1D) receptors, we explored the structure-affinity relationships of a series of related derivatives. Each of the aromatic substituents was removed and then reinstated in a systematic manner to determine the influence of the individual substituents on binding. It was found that all of the aromatic substituents of 8 act in concert to impart high affinity. However, although the 3-hydroxy group could be removed without significantly reducing affinity for h5-HT(1D) (i.e., human 5- HT(1Dα)) receptors, this modification reduced h5-HT(1B) (i.e., human 5- HT(1Dβ)) receptor affinity by nearly 50-fold. The 2,6-dimethyl groups also contribute to binding but seem to play a greater role for h5-HT(1B) binding than h5-HT(1D) binding. With the appropriate structural modifications, several compounds were identified that display 20- to > 100-fold selectivity for h5-HT(1D) versus h5-HT(1B) receptors. Preliminary functional data suggest that these compounds behave as agonists. Given that 5-HT(1D) agonists are currently being explored for their antimigraine action and that activation of h5-HT(1B) receptors might be associated with cardiovascular side effects, h5- HT(1D)selective agents may offer a new lead for the development of therapeutically efficacious agents.
SELECTIVITY AND MECHANISM IN THE SIDE-CHAIN HALOGENATION OF METHYLBENZENES PROMOTED PHOTOCHEMICALLY AND BY METAL COMPLEXES IN THE PRESENCE OF HALIDE IONS
Baciocchi, Enrico,Crescenzi, Manuela
, p. 6525 - 6536 (2007/10/02)
The intramolecular selectivity in a variety of side-chain halogenations of alkyl-aromatics has been determined in AcOH by measuring the isomeric distribution in the reactions of 4-t-butyl- and 4-chloro-1,2-dimethylbenzene (1 and 2, respectively) with: Br2/hν, CAN/Br-, CAN=cerium(IV) ammonium nitrate, cobalt(III) acetate/Br-, S2O8=/Br-, N-bromosuccinimide (in CCl4), Cl2/hν, CAN/Cl-, cobalt(III) acetate/Cl-.In the bromination reactions selectivity is independent of the reaction conditions, thus suggesting that in all brominating systems Br. is the actual reacting species.Very surprisingly, with 1 as the substrate, Cl2/hν is a more selective system than Br2/hν.With 2 the two systems display similar selectivity.It has been suggested that in AcOH the transition state for photochlorination has an electron transfer character which increases as the substrate becomes more electron rich.The idea of a "variable" transition state for the photochlorination in AcOH is supported by data of relative reactivity of substituted toluenes indicating that the effect on the rate increases as the substituent becomes more electron donor.AcOH must have an essential role in this respect since in CCl4 situation returns to be "normal" with chlorination less selective than bromination.Selectivity of CAN/Cl- is very similar to that of Cl2/hν, whereas significant differences are observed with cobalt(III) acetate/Cl-.Probably Cl. and a cobalt(III) chloride complex are the reacting species in CAN/Cl- and cobalt(III) acetate/Cl-, respectively.
