75659-06-2Relevant articles and documents
Resolution of racemic amines via lipase-catalyzed benzoylation: Chemoenzymatic synthesis of the pharmacologically active isomers of labetalol
Sanfilippo, Claudia,Paternò, Alfio Adriano,Patti, Angela
, p. 79 - 84 (2018/04/30)
Lipase-catalyzed benzoylation of amines was shown to be feasible, in some cases with high enantioselectivity, and the best results were obtained using immobilized lipase from Candida antarctica (Novozym 435) and methyl benzoate as acyl donor in the presence of molecular sieves. The procedure was optimized for the resolution of (±)-1-methyl-3-phenylpropylamine, a key intermediate in the synthesis of antihypertensive drug labetalol, and the enantiopure (R)-benzamide was then converted into the pharmacologically active isomers of the drug. In comparison with the reported synthesis of chiral isomers of labetalol, this chemoenzymatic route offers the advantage in the lack of any chiral stoichiometric auxiliary.
C1-symmetric rare-earth-metal aminodiolate complexes for intra- and intermolecular asymmetric hydroamination of alkenes
Reznichenko, Alexander L.,Hultzsch, Kai C.
, p. 1394 - 1408 (2013/05/21)
A series of novel C1-symmetric aminodiolate rare-earth-metal complexes have been prepared via arene elimination from [Ln(o-C 6H4CH2NMe2)3] (Ln = Y, Lu) and the corresponding aminodiol proligand. The NOBIN-derived aminodiolate ligands feature sterically demanding triphenylsilyl and methyldiphenylsilyl ortho substituents on the naphtholate moiety and substituents of varying steric demand ranging from tert-butyl to tris(3,5-xylyl)silyl on the phenolate moiety. Complexes with a triphenylsilyl substituent on the naphtholate moiety displayed good catalytic activity in the hydroamination/cyclization of aminoalkenes, while complexes with a methyldiphenylsilyl substituent exhibited somewhat lower reactivity. The highest enantioselectivities for five- and six-membered-ring formation were observed utilizing complex 9c-Lu (R1 = Ph, R 2 = Me, R3 = SiPh3) in the cyclization of (2,2-diphenylpent-4-enyl)amine (92% ee, Nt = 200 h-1 at 25 C) and (2,2-diphenylhex-5-enyl)amine (73% ee, Nt = 20 h-1 at 25 C). The complexes can be applied in asymmetric intermolecular hydroaminations of 1-heptene and 4-phenyl-1-butene with benzylamine with enantioselectivities of up to 40% ee using complex 9b-Y (R1 = Ph, R2 = Me, R3 = SiPh2Me). Here the higher catalytic activities are achieved with catalysts having a methyldiphenylsilyl substituent on the naphtholate moiety. Lanthanum aminodiolate catalysts generated in situ from [La{CH(C6H5)NMe2} 3] did not exhibit improved catalytic activity in the intermolecular hydroamination in comparison to the corresponding yttrium and lutetium catalysts. The overall catalytic activities of the aminodiolate complexes are somewhat diminished in comparison to previously studied binaphtholate complexes due to the presence of the additional amine donor site in the ligand framework.
Towards a practical br?nsted acid catalyzed and hantzsch ester mediated asymmetric reductive amination of ketones with benzylamine
Wakchaure, Vijay N.,Nicoletti, Marcello,Ratjen, Lars,List, Benjamin
supporting information; experimental part, p. 2708 - 2710 (2011/02/16)
We report the use of benzylamine as the amine component in Hantzsch ester mediated and chiral Br?nsted acid catalyzed enantioselective reductive aminations of ketones. The method is noteworthy because the benzyl group is easily removable, and amine product purification is achieved through Hantzsch ester oxidation product removal via basic hydrolysis.
