65-64-5Relevant articles and documents
Extending the Scope of the B(C6F5)3-Catalyzed C=N Bond Reduction: Hydrogenation of Oxime Ethers and Hydrazones
Mohr, Jens,Porwal, Digvijay,Chatterjee, Indranil,Oestreich, Martin
, p. 17583 - 17586 (2015/12/05)
The B(C6F5)3-catalyzed hydrogenation is applied to aldoxime triisopropylsilyl ethers and hydrazones bearing an easily removable phthaloyl protective group. The C=N reduction of aldehyde-derived substrates (oxime ethers and hydrazones) is enabled by using 1,4-dioxane as the solvent known to participate as the Lewis-basic component in FLP-type heterolytic dihydrogen splitting. More basic ketone-derived hydrazones act as Lewis bases themselves in the FLP-type dihydrogen activation and are therefore successfully hydrogenated in nondonating toluene. The difference in reactivity between aldehyde- and ketone-derived substrates is also reflected in the required catalyst loading and dihydrogen pressure.
ADENOSINE A2A RECEPTOR ANTAGONISTS
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Page/Page column 9, (2008/12/04)
Compounds having the structural formula I or a pharmaceutically acceptable salt thereof, wherein: X1 and X2 are 1-3 substituents independently selected from the group consisting of H, alkyl, halo, —CF3, —OCF3, alkoxy, —OH and —CN;n is 0, 1 or 2; andR and R1 are H or alkyl; also disclosed is the use of the compounds in the treatment of CNS diseases such as Parkinson's disease, alone or in combination with other agents for treating CNS diseases, pharmaceutical compositions comprising them and kits comprising the components of the combinations.
Limitations in the synthesis of high molecular weight polymers via nitroxide-mediated controlled radical polymerization: Experimental studies
Gray, Maisha K.,Zhou, Hongying,Nguyen, SonBinh T.,Torkelson, John M.
, p. 5792 - 5797 (2007/10/03)
Limitations associated with preparing high molecular weight polystyrene (PS) by nitroxide-mediated controlled radical polymerization have been tested by considering the role of unimolecular initiator concentration on active polymer radical concentration and thus degree of polymerization. Recent theories ignoring autopolymerization effects lead to the conclusion that, at low monomer conversion, the number-average molecular weight, Mn, scales with the -2/3 power of unimolecular initiator concentration. Bulk polymerizations were done using either α-methylstyryl di-tert-butyl nitroxide (A-T) as unimolecular initiator or PS macroinitiator made from A-T. These initiators allow relatively low reaction temperature (77, 87, or 97 °C) and moderate, but not eliminate, the contribution of autopolymerization or thermal initiation of polymerization. By varying unimolecular initiator concentration over nearly 4 orders of magnitude, well-controlled PS, with polydispersity index ≤ 1.4, can be made with Mn values in the range 114 000-238 000 g/mol using either A-T as initiator or a PS macroinitiator. For conditions yielding controlled PS, in general the experimental Mn-initiator concentration data afforded good agreement with the -2/3 power-law expression and allowed estimation of the equilibrium constant for the capping-uncapping reaction. However, attempts to make controlled, higher molecular weight PS by further reducing initiator concentration resulted in loss of control due to autopolymerization effects. The impact of autopolymerization in producing well-controlled PS was evident from studies yielding a nearly constant conversion as a function of macroinitiator concentration.
