129446-42-0Relevant academic research and scientific papers
Photo aldol reactions with 5-methoxyoxazoles: Highly regio- and diastereoselective synthesis of α-amino β-hydroxy carboxylic acid derivatives
Griesbeck, Axel G.,Bondock, Samir
, p. 555 - 559 (2003)
A versatile route to derivatives of α-amino β-hydroxy carboxylic acids, either with tertiary (from a corresponding glycine equivalent) or a quaternary α-carbon center is described. The key reaction is the cycloaddition of electronically excited carbonyl c
Photocycloaddition of 5-methoxyoxazoles to aldehydes and α-keto esters: A comprehensive view on stereoselectivity, triplet biradical conformations, and synthetic applications of paternbchi adducts
Griesbeck, Axel G.,Bondock, Samir
, p. 573 - 580 (2008)
The photocycloaddition of carbonyl compounds (aldehydes and keto esters, respectively) with 5-methoxyoxazoles bearing substituents at C2 and C4 is described with respect to regio- and diastereoselectivity. In all cases the reactions proceed with excellent regioselectivity and with high to moderate (exo) diastereoselectivity independent of the nature of the excited carbonyl compound. The products can be easily ring-opened to give α-amino, θ-hydroxy carboxylic acid derivatives. CSIRO 2008.
Synthesis of erythro-α-Amino β-hydroxy Carboxylic Acid Esters by Diastereoselective Photocycloaddition of 5-Methoxyoxazoles with Aldehydes
Griesbeck, Axel G.,Bondock, Samir,Lex, Johann
, p. 9899 - 9906 (2007/10/03)
A new photoaldol route to α-amino-β-hydroxy carboxylic acid esters is initiated by the photocycloaddition of aromatic or aliphatic aldehydes to 5-methoxyoxazoles. The 4-unsubstituted 5-methyloxazole 1 gave the cycloadducts 8a-f in high yields and excellent exo-diastereoselectivities. Hydrolysis of 8a-f gives the N-acetyl α-amino-β-hydroxy esters 9a-f, which could be subsequently converted into the corresponding Z-didehydro α-amino acids 10a-f. Quartenary α-amino-β-hydroxy esters 12, 14, 16, 18, and 20, which are stable against dehydration, were obtained from the 4-alkylated 5-methoxyoxazoles 2-6, in most cases highly erythro-selective due to the high degree of stereocontrol (exo) at the photocycloaddition (to give 11, 13, 15, 17, and 19) level. The relative configurations of the N-acetyl α-amino-β-hydroxy esters were determined by NMR spectroscopy and comparison with chiral pool-derived compounds as well as by X-ray structure determination of the ester 23, formed by hydrolysis of the cycloadduct 22, derived from photocycloaddition of propionaldehyde to the isoleucine-derived oxazole 21.
Peptide inhibitors of CDK2-cyclin A that target the cyclin recruitment-Site: Structural variants of the C-Terminal Phe
Atkinson, Gail E.,Cowan, Angela,McInnes, Campbell,Zheleva, Daniella I.,Fischer, Peter M.,Chan, Weng C.
, p. 2501 - 2505 (2007/10/03)
A focused series of octapeptides based on the lead compound H-His-Ala-Lys-Arg-Arg-Leu-Ile-Phe-NH2 1, in which the C-terminal phenylalanine residue was replaced by α and/or β-modified variants, was synthesized using solid-phase chemistry. Both the L-threo-β-hydroxy-phenylalanine (β-phenylserine, Pse) and (2S)-phenylalaninol derivatives, as competitive binders at the cyclin-recruitment site, displayed potent inhibitory activity towards the CDK2-cyclin A complex. Unexpectedly, the D-threo-Pse derivatives also showed inhibitory activity.
Synthesis of functionalized phenylalanine derivatives by ring opening reactions of 3-arylaziridine-2-carboxylic esters
Legters, Johan,Thijs, Lambertus,Zwanenburg, Binne
, p. 16 - 21 (2007/10/02)
Ring-opening reactions of 3-arylaziridine-2-carboxylic esters with various nucleophiles are described.Racemic methyl 3-(4-methoxyphenyl)-, 3-phenyl- and 3-(4-nitrophenyl)aziridine-2-carboxylate (1a, 1b and 1c, respectively) were selected as substrates.In the absence of acid, no ring opening occurred.On treatment with ethereal hydrogen chloride, 1a gave a mixture of diastereomers 2a, whereas 1b and 1c gave mixtures of regioisomers 2b/3b and 2c/3c, respectively.Boron-trifluoride etherate catalyzed reaction of 1a with benzenethiol and indole also resulted in the formation of diastereomeric ring-opened products 4a and 6a, respectively, due to the electron-releasing properties of the p-methoxy group.Only C3 attack was observed.Under the same conditions, 1b and 1c gave a clean SN2-type ring opening, leading to diastereomerically pure products 4b, 4c, 6b and 6c.Reaction of 1b with acetic acid gave 7 in an SN2-type ring opening at C3, followed by an O->N acyl shift.Treatment of enantiopure (+)-(2S,3R)-1b with benzenethiol, indole and acetic acid gave the corresponding enantiomerically pure β-functionalized α-amino acid derivatives.Functionalization of 1b at nitrogen strongly increased the reactivity: N-acylaziridine 8 isomerized to trans-oxazoline 11 when treated with boron trifluoride etherate in acetonitrile.
Resolution of β-hydroxy-α-amino acids by the action of proteases on their N-acyl methyl esters
Chenevert, Robert,Letourneau, Martin,Thiboutot, Sonia
, p. 960 - 963 (2007/10/02)
Methyl N-acetyl phenylserinates (1, 2), methyl N-acetyl nitrophenylserinates (3, 4), and methyl N-benzoyl threoninates (5, 6) were resolved conveniently into the enantiomers with high optical purities by enzymatic hydrolysis in the presence of α-chymotryp
