29618-17-5Relevant academic research and scientific papers
Asymmetric hydroazidation of α-substituted vinyl ketones catalyzed by chiral primary amine
Xue, Zai-Kun,Fu, Nian-Kai,Luo, San-Zhong
, p. 1083 - 1086 (2017)
We report herein the first example of asymmetric hydroazidation of α-substituted vinyl ketones by using chiral primary amines as the catalysts. A simple chiral primary-tertiary diamine catalyst derived from L-phenylalanine was found to readily promote this aza-Michael addition reaction with enamine protonation as the key stereogenic step, thus enabling the effective synthesis of α-chiral β-azido ketones with good yields and moderate enantioselectivities.
Protecting-Group-Free Amidation of Amino Acids using Lewis Acid Catalysts
Sabatini, Marco T.,Karaluka, Valerija,Lanigan, Rachel M.,Boulton, Lee T.,Badland, Matthew,Sheppard, Tom D.
supporting information, p. 7033 - 7043 (2018/05/04)
Amidation of unprotected amino acids has been investigated using a variety of ‘classical“ coupling reagents, stoichiometric or catalytic group(IV) metal salts, and boron Lewis acids. The scope of the reaction was explored through the attempted synthesis of amides derived from twenty natural, and several unnatural, amino acids, as well as a wide selection of primary and secondary amines. The study also examines the synthesis of medicinally relevant compounds, and the scalability of this direct amidation approach. Finally, we provide insight into the chemoselectivity observed in these reactions.
Novel bifunctional thiourea-ammonium salt catalysts derived from amino acids: Application to highly enantio- and diastereoselective aza-Henry reaction
Wang, Hong-Yu,Chai, Zhuo,Zhao, Gang
supporting information, p. 5104 - 5111 (2013/06/27)
The development of new efficient and easily accessible catalysts has been one of the focuses in asymmetric phase-transfer catalysis. In this paper, a novel class of chiral bifunctional thiourea-ammonium phase-transfer catalysts were synthesized from commercially available α-amino acids. The structural modularity of these catalysts permits facile tunings to achieve optimum results, which was demonstrated in catalyzing the aza-Henry reaction with excellent enantioselectivities (up to 99.5% ee) and diastereoselectivities (up to >25:1 dr).
Synthesis of a new class of bis(thiourea)hydrazide pseudopeptides as potential inhibitors of β-sheet aggregation
Klein, Jan J.,Hecht, Stefan
supporting information; experimental part, p. 330 - 333 (2012/02/04)
The modular synthesis of a novel pseudopeptide scaffold based on a bis(thiourea)hydrazide motif is reported. This compound class is designed to display "amphifinity", i.e. association with a peptide strand on one but not the other face of the scaffold, and hence could potentially inhibit β-sheet aggregation.
SULTAM DERIVATIVES
-
Page/Page column 26, (2011/06/19)
The present invention relates to compounds according to formula 1, which exhibit cytotoxic activity. The compounds may be used in the treatment of cancer.
Ring-Opening polymerization of lactides catalyzed by natural Amino-Acid based zinc catalysts
Darensbourg, Donald J.,Karroonnirun, Osit
experimental part, p. 2360 - 2371 (2010/05/14)
A series of chiral NNO-tridentate Schiff base ligands derived from natural amino acids were reacted with zinc(bis-trimethylsilylamide)2 to provide metal complexes which have been fully characterized. One of these derivatives was further reacted
Novel bifunctional chiral urea and thiourea derivatives as organocatalysts: Enantioselective nitro-Michael reaction of malonates and diketones
Andres, Jose M.,Manzano, Ruben,Pedrosa, Rafae
supporting information; experimental part, p. 5116 - 5119 (2009/05/27)
A modular synthesis of novel bifunctional urea and thiourea organocatalysts derived from cheap, easily accessible natural and non-natural amino acids was reported. The generality of the synthesis was demonstrated in the preparation of catalysts 4a-i in th
Structure-activity study of endomorphin-2 analogs with C-terminal modifications by NMR spectroscopy and molecular modeling
Wang, Chang-lin,Yao, Jin-long,Yu, Ye,Shao, Xuan,Cui, Yun,Liu, Hong-mei,Lai, Lu-hao,Wang, Rui
, p. 6415 - 6422 (2008/12/21)
Endomorphin-2 (EM-2) is a putative endogenous μ-opioid receptor ligand. To get insight into the important role of C-terminal amide group of EM-2, we investigated herein a series of EM-2 analogs by substitution of the C-terminal amide group with -NHNH2, -NHCH3, -N(CH3)2, -OCH3, -OCH2CH3, -OC(CH3)3, and -CH2-OH. Their binding affinity and bioactivity were determined and compared. Despite similar (analogs 1, 4, and 7) or decreased (analogs 2, 3,5, and 6) μ affinity in binding assays, all analogs showed low guinea pig ileum (GPI) and mouse vas deferens (MVD) potencies compared to their parent peptide. Interestingly, as for analogs 2 and 3 (a single and double N-methylation of C-terminal amide), the potency order with the Ki (μ) values was 2 > 3; for the C-terminal esterified analogs 4-6, the potency order with the Ki (μ) values was 4 > 5 > 6. Thus, we concluded that the steric hindrance of C-terminus might play an important role in opioid receptor affinity. We further investigated the conformational properties of these analogs by 1D and 2D 1H NMR spectroscopy and molecular modeling. Evaluating the ratios of cis- and trans-isomers, aromatic interactions, dihedral angles, and stereoscopic views of the most convergent conformers, we found that modifications at the C-terminal amide group of EM-2 affected these analog conformations markedly, therefore changed the opioid receptor affinity and in vitro bioactivity.
Structure-activity relationships of the peptide deformylase inhibitor BB-3497: Modification of the P2′ and P3′ side chains
Davies, Stephen J.,Ayscough, Andrew P.,Beckett, R. Paul,Clements, John M.,Doel, Sheila,Pratt, Lisa M.,Spavold, Zoe M.,Thomas, S. Wayne,Whittaker, Mark
, p. 2715 - 2718 (2007/10/03)
Structural modifications to the peptide deformylase inhibitor BB-3497 are described. In this paper, we describe the initial SAR around this lead for modifications to both the P2′ and P3′ side chains. Enzyme inhibition and antibacterial activity data revealed that a variety of substituents are tolerated at the P2′ and P3′ positions of the inhibitor backbone. The data from this study highlights the potential for modification at the P2′ and P3′ positions to optimise the physicochemical properties.
New auxiliaries for copper-catalyzed asymmetric Michael reactions: Generation of quaternary stereocenters at room temperature
Christoffers, Jens,Mann, Alexander
, p. 1014 - 1027 (2007/10/03)
Dialkyl amides of L-valine, L-isoleucine, and L-tert-leucine (2) are excellent chiral auxiliaries for the construction of quaternary stereocenters at ambient temperature. Enaminoesters 3, prepared from these auxiliaries 2 and Michael donors 1. undergo a copper-catalyzed asymmetric Michael reaction with methyl vinyl ketone (MVK, 4) to afford products 5 in 70-90% yield and 90-99% ee (enantiomeric excess). The exclusion of moisture or oxygen is not necessary. The auxiliaries 2 are readily available by standard procedures. After workup they can be recovered almost quantitatively.
