752956-46-0Relevant academic research and scientific papers
BETA-AMINO ACIDS AND METHODS AND INTERMEDIATES FOR MAKING SAME
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Page/Page column 17, (2011/10/02)
Disclosed are β-amino acids that are unsubstituted in the β position; that are substituted in the β position with an aryl group; that are substituted in the α position with an aryl group; that bear two substituents in the α position; and/or that are substituted in the α and β positions with groups which, together with the carbon atoms at the α and β positions, form a ring. Also disclosed are methods for making the above-mentioned β-amino acids and other β-amino acids which involve providing an α,β-unsaturated imide; converting the α,β-unsaturated imide to a 2-substituted-isoxazolidin-5-one; and converting the 2-substituted-isoxazolidin-5-one to a β-amino acid.
A 4-hydroxypyrrolidine-catalyzed mannich reaction of aldehydes: Control of anti-selectivity by hydrogen bonding assisted by bronsted acids
Gomez-Bengoa, Enrique,Maestro, Miguel,Mielgo, Antonia,Otazo, Itziar,Palomo, Claudio,Velilla, Irene
experimental part, p. 5333 - 5342 (2010/10/03)
An anti-selective Mannich reaction of aldehydes with N-sulfonyl imines has been developed by using a 4-hydroxypyrrolidine in combination with an external Bronsted acid. The catalyst design is based on three elements: the ct-substituent of the pyrrolidine, the 4-hydroxy group, and the Bronsted acid, the combination of which is essential for high chemical and stereochemical efficiency. The reaction works with aromatic aldehydederived imines, which have rarely been employed in previously reported enamine-based anti-Mannich reactions. Additionally, both N-tosyl and N-nosyl imines can be successfully used and the Mannich adducts can be easily reduced or oxidized, and after N-deprotection the corresponding ss-amino acids and ss-amino alcohols can be obtained with good yields. The results also show that this ternary catalytic system may be practical in other enamine-based reactions.
Enantioselective synthesis of α,β-disubstituted-β-amino acids
Sibi, Mukund P.,Prabagaran, Narayanasamy,Ghorpade, Sandeep G.,Jasperse, Craig P.
, p. 11796 - 11797 (2007/10/03)
Highly diastereoselective and enantioselective addition of N-benzylhydroxylamine to imides 17 and 20-30 produces α,β-trans-disubstituted N-benzylisoxazolidinones 19 and 31-41. These reactions proceed in 60-96% ee with 93-99% de's using 5 mol % of Mg(NTf2)2 and ligand 18. The product isoxazolidinones can be hydrogenolyzed directly to provide ∞,β-disubstituted-β-amino acids. Copyright
Asymmetric Syntheses of β-Phenylalanine, α-Methyl-β-phenylalanines and Derivatives
Davies, Stephen G.,Garrido, Narciso M.,Ichihara, Osamu,Walters, Iain A. S.
, p. 1153 - 1155 (2007/10/02)
A strategy of highly stereoselective conjugate additions of lithium (R)-(α-methylbenzyl)benzylamide to tert-butyl cinnamate and its 2-methyl derivative combined with appropriate tandem or sequential electrophilic quenches allows the asymmetric syntheses of β-phenylalanyl (95percent enantiomeric excess) and homochiral (2R,3S)- and (2S,3S)-α-methyl-β-phenylalanine and the corresponding β-lactams (3R,4S)- and (3S,4S)-3-methyl-4-phenylazetidinones.
