16771-89-4Relevant academic research and scientific papers
RUTHENIUM-CATALYZED HYDROAMINATION OF OLEFINS
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Page/Page column 20-21; 30, (2010/02/13)
Applicants have unexpectedly discovered that catalysts made from a ruthenium catalyst precursor or preformed ruthenium catalysts as otherwise described in the present specification are capable of effecting the addition of a N-H bond across an olefin C=C (olefinic) bond of a substrate with a high degree of regioselectivity and enantioselectivity in high yield. These addition reactions proceed in an anti-Markovnikov or Markovnikov fashion depending upon the catalyst precursor used to generate the ruthenium catalyst which actually participates in the addition reaction. The present invention relates to methods of adding N-H bonds across an olefinic bond in a substrate, using a ruthenium catalyst precursor or catalyst I comprising a compound according to the general structure I: Formula (I) where Ru is a ruthenium atom; L1 represents one or more coordinated ancillary ligands, which may be all the same ligand or which may be a combination of different ligands, each of which may be neutral or formally charged, and each of which may be monodentate and coordinated to ruthenium through a single atom or which may be linked or chelated and bound through more than one atom; L2 represents one or more formally charged ligands which are the same or different and which are optionally susceptible to removal with a strong acid; and x is 0-6, preferably 1, y is 0-6, preferably 2 and n is 1-4, preferably 1.
Ruthenium-Catalyzed Anti-Markovnikov Hydroamination of Vinylarenes
Utsunomiya, Masaru,Hartwig, John F.
, p. 2702 - 2703 (2007/10/03)
A ruthenium-catalyzed intermolecular, anti-Markovnikov hydroamination of vinylarenes with secondary aliphatic and benzylic amines is reported. The combination of Ru(cod)(2-methylallyl)2, 1,5-bis(diphenylphosphino)pentane, and triflic acid was the most effective catalyst of those tested. Control reactions conducted without ligand or acid did not form the amine. The reaction of morpholine, piperidine, 4-phenylpiperazine, 4-BOC-piperazine, 4-piperidone ethylene ketal, and tetrahydroisoquinoline with styrene in the presence of 5 mol % of this catalyst formed the corresponding β-phenethylamine products in 64?96% yield, with 99% regioselectivity, and without enamine side products. Acyclic amines such as n-hexylmethylamine and N-benzylmethylamine reacted with styrene in 63 and 50% yields, respectively. Alkyl-, methoxy-, and trifluoromethyl-substituted styrenes reacted with morpholine in the presence of this catalyst or a related one containing 1,1′-bis(diisopropylphosphino)ferrocene as ligand to give the products in 51?91%. Further, the hydroamination of α-methyl styrene was observed for the first time with a homogeneous transition metal catalyst. Preliminary mechanistic studies showed that the reaction occurred by direct, irreversible, anti-Markovnikov hydroamination and that the mechanism of the ruthenium-catalyzed hydroamination is likely to be distinct from that of the recently reported rhodium-catalyzed reaction. Copyright
Structure-activity relationship studies of novel 4-[2-[bis(4- fluorophenyl)methoxy]ethyl]-1-(3-phenylpropyl)piperidine analogs: Synthesis and biological evaluation at the dopamine and serotonin transporter sites
Dutta,Xu,Reith
, p. 749 - 756 (2007/10/03)
Several analogs of the potent dopamine (DA) transporter ligand 4-[2- [bis(4-fluorophenyl)-methoxy]ethyl]-1-(3-phenylpropyl)piperidine, 1b, were made and biologically evaluated for their binding at the DA and serotonin (5HT) transporters in rat striatal membranes. Different alkyl chain lengths and substitutions were introduced in these molecules to generate an optimum activity and selectivity for the DA transporter. In general, unsubstituted and fluoro-substituted compounds were the most active and selective for the DA transporter. The compound 4-[2(diphenylmethoxy)ethyl]-1-benzylpiperidine, 9a, showed high potency and was the most selective for the DA transporter (5HT/DA = 49) in this series of compounds. Some of these novel analogs were found to be more selective in binding at the DA transporter than the original GBR 12909 molecule, 1-[2-[bis(4-fluorophenyl)methoxy]ethyl]-4-(3- phenylpropyl)piperidine.
New antihistaminic N-heterocyclic 4-piperidinamines. 1. Synthesis and antihistaminic activity of N-(4-piperidinyl)-1H-benzimidazol-2-amines
Janssens,Torremans,Janssen,Stokbroekx,Luyckx
, p. 1925 - 1933 (2007/10/02)
The synthesis of a series N-(4-piperidinyl)-1H-benzimidazol-2-amines and the preliminary evaluation of their in vitro and in vivo antihistaminic activity are described. Cyclodesulfurization of (2-aminophenyl) thioureas with mercury(II) oxide resulted in 2-aminobenzimidazole intermediates, which were monoalkylated on the endo-nitrogen atom. After deprotection of the piperideine nitrogen atom with 48% aqueous hydrobromic acid solution, the title compounds were obtained by three different methods, viz. alkylation, reductive amination, or oxirane ring-opening reactions. The in vivo antihistaminic activity was evaluated by the compound 48/80 induced lethality test in rats and histamine-induced lethality test in guinea pigs after oral and/or subcutaneous administration. The duration of action, for a selected number of compounds, was studied in the guinea pig. The phenylethyl derivatives showed the most potent antihistamine properties after oral administration in both animal species.
