53296-34-7Relevant articles and documents
Enantioselective Deaminative Alkylation of Amino Acid Derivatives with Unactivated Olefins
Cai, Yue-Ming,Martin, Ruben,Rui, Xi-Yan,Shang, Ming,Sun, Shang-Zheng,Wang, Jia-Bao,Yao, Hong-Qing,Zhang, De-Liang
supporting information, p. 1130 - 1137 (2022/02/05)
Herein, we report the first Ni-catalyzed enantioselective deaminative alkylation of amino acid and peptide derivatives with unactivated olefins. Key for success was the discovery of a new sterically encumbered bis(oxazoline) ligand backbone, thus offering a de novo technology for accessing enantioenriched sp3-sp3 linkages via sp3 C-N functionalization. Our protocol is distinguished by its broad scope and generality across a wide number of counterparts, even in the context of late-stage functionalization. In addition, an enantioselective deaminative remote hydroalkylation reaction of unactivated internal olefins is within reach, thus providing a useful entry point for forging enantioenriched sp3-sp3 centers at remote sp3 C-H sites.
The microenvironment and pKaperturbation of aminoacyl-tRNA guided the selection of cationic amino acids
Hazra, Bibhas,Prasad, Mahesh,Roy, Rajat,Tarafdar, Pradip K.
supporting information, p. 8049 - 8056 (2021/10/04)
The proteinogenic lysine (Lys) and arginine (Arg) have multiple methylene groups between α-carbon and the terminal charged centre. Why nature did not select ornithine (Orn), 2,4-diamino butyric acid (Dab) and 2,3-diamino propionic acid (Dpr) with fewer methylene groups in the side chain remains an important question! The propensity of aminoacyl-tRNA (aa-tRNA) model substrates towards self-degradationviaintramolecular lactamization was studied using UV spectroscopy and1H-NMR titration, which showed that Lys and Arg remain stable, and Orn and Dab cyclize to lactam. Hydrophobicity-assisted surface mediated model peptide formation highlighted that the microenvironment and pKaperturbation led to poor regioselectivity (α-aminevs.terminal amine) in Dpr and other non-proteinogenic analogues. The α-selectivity became even poorer in the presence of phosphate, making them ill-suited for peptide synthesis. Superior regioselectivity of the Lys aa-tRNA model substrate suggests that the extra methylene bridge helped nature to separate the microenvironments of the α-amine and ε-amine to synthesize the peptide backbone.
Elucidation of absolute configuration of ophiorrhiside a by comparison of ecd spectra with that of model chiral compound having a 1,2,3,4-tetrahydro-β-carbolin-3-one skeleton
Onozawa, Tadayoshi,Kogure, Noriyuki,Takayama, Hiromitsu,Kitajima, Mariko
, p. 35 - 43 (2021/02/12)
A chiral 1,2,3,4-tetrahydro-β-carbolin-3-one having a substituent at C-1 was synthesized from L-leucine and used to elucidate the absolute configuration at C-3 of ophiorrhiside A, a monoterpenoid glucoindole alkaloid.
Preparation method of N-trimethyl silicon ethoxycarbonyl-N-methyl-L/D-leucine
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Paragraph 0078-0080; 0096-0098, (2021/06/02)
The invention relates to a preparation method of N-(trimethylsilyl) ethoxycarbonyl group-N-methyl-L/D-leucine. The preparation method comprises the following steps: adding N-methyl-L/D-leucine hydrochloride, a trimethylsilylethoxycarbonyl protecting group reagent and alkali into a mixed solution of a polar solvent and water, and carrying out a reaction, so as to obtain the N-trimethylsilylethoxycarbonyl-N-methyl-L/D-leucine. According to the preparation method, the N-trimethyl silicon ethoxycarbonyl-N-methyl-L/D-leucine with high chiral purity, high chemical purity and high yield can be obtained, the chiral purity and the chemical purity can reach 99% or above, the yield can reach 60% or above, and the preparation method is simple in process, mild in condition and suitable for being applied to large-scale industrial production.
α-Amino Acids and α,β-Dipeptides Intercalated into Hydrotalcite: Efficient Catalysts in the Asymmetric Michael Addition Reaction of Aldehydes to N-Substituted Maleimides
Landeros, José M.,Cruz-Hernández, Carlos,Juaristi, Eusebio
supporting information, p. 5117 - 5126 (2021/09/13)
In this work, a series of α-amino acids (L-Phe, D-Phe, L-Trp) and several α,β-dipeptides (H2N-L-Val-N-Bn-β-Ala-COOH and H2N-L-Leu-N-Bn-β-Ala-COOH) intercalated into hydrotalcite (Mg/Al, x=0.333) were prepared by high speed ball milling (HSBM) assisted rehydration/reconstruction methods, followed by sonication and mechanical stirring. All organic-inorganic hybrid samples were characterized by powder X-ray diffraction (XRD) and FTIR-ATR spectroscopy. The catalytic activity of the resulting hydrotalcite-supported materials (natural and hybrid) was evaluated in the asymmetric Michael addition reaction of α,α-disubstituted-aldehydes to N-substituted-maleimides. Pristine (HTS), calcined (HTC) and water-reconstructed (HTR-l) hydrotalcite-derived materials exhibited very low catalytic activities, affording racemic mixtures of the anticipated Michael adduct. By contrast, hybrid materials showed better activities, especially HTR-α-amino acid catalysts afforded Michael products in up to 94 % yield and with rather high enantioselectivity (enantiomeric ratio (e.r.) up to 99 : 1) at room temperature under neat reaction conditions. The effect of solvents and Br?nsted basic or acidic additives was evaluated using the best hybrid catalyst, HTR-L-Phe. In addition, recycling and reuse of the catalyst (up to 4 cycles) and large-scale experiments was successfully carried out.
INHIBITORS OF CORONAVIRUS PROTEASE
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Paragraph 00147; 00149; 00150; 00157-00158; 00167-00169, (2021/11/26)
The present document describes compounds that are inhibitors of coronavirus proteases, and more particularly to compounds that are inhibitors of SARS-CoV-2 viral proteases. Also, the present document describes methods and uses of the compounds for the treatment or prevention of viral infection, such as SARS-CoV-2 infections, in a subject in need of treatment.
Design and preparation of a novel prolinamide-based organocatalyst for the solvent-free asymmetric aldol reaction
Martins, Rafaela de S.,Pereira, Mathias P.,de Castro, Pedro P.,Bombonato, Fernanda I.
, (2019/12/24)
The preparation of four novel organocatalysts as highly diastereo and enantioselective catalysts for the solvent-free asymmetric aldol reaction was described. These organocatalysts were synthesized in eight steps applying simple and commercially available starting materials. The best results were obtained for the proline-derived catalyst, providing access to the desired adducts in up to 95% yield, 1:19 syn/anti and 98% e.e. Moreover, even sterically bulky aldehydes and substituted cyclohexanones were well tolerated. DFT calculations and control experiments indicated that several hydrogen bonding interactions between the aldehyde and the enamine intermediate are responsible for the stereoselective chiral induction process and that the trifluoroacetate counter-anion is crucial for the attainment of higher stereoselectivities.
Cytotoxic activity of synthetic chiral amino acid derivatives
de Castro, Pedro P.,Siqueira, Raoni P.,Conforte, Luiza,Franco, Chris H.J.,Bressan, Gustavo C.,Amarante, Giovanni W.
, p. 193 - 200 (2019/12/28)
Cancer is a chronic degenerative disease considered one of the most important causes of death worldwide. In this context, a series of dual-protected amino acid derivatives was synthesized and evaluated as potential novel anticancer agents. The 40 derivatives were prepared in up to three reaction steps. The cytotoxic activities were screened in vitro against a panel of tumor and non-tumor cells using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Among the synthesized derivatives, three of them showed promising activity against cancer cells with half-maximal inhibitory concentration (IC50) ranging between 1.7-6.1 μM. The most promising derivative, bearing both a lipophilic N-alkyl diamine moiety and a protected amino acid scaffold showed a selectivity index of 3.4 towards tumor cells. The N-alkyl diamine moiety seems to play a crucial role in the enhancement of the anticancer activity. On the other hand, the incorporation of an amino acid scaffold resulted in increase in the selectivity towards cancer cell lines.
Synthesis, in vitro and in vivo biological evaluation of dihydroartemisinin derivatives with potential anti-Toxoplasma gondii agents
Deng, Hao,Huang, Xing,Jin, Chun-Mei,Jin, Chunmei,Quan, Zhe-Shan
, (2019/12/26)
In this study, four series of dihydroartemisinin derivatives were designed, synthesized, and evaluated for anti-toxoplasma gondii activity, and calculated the selectivity index (SI). It was the higher the SI, the better the effect of this compound against Toxoplasma gondii. Our goal was to filter out compounds that were bigger SI than the lead compound. The compound with the highest SI was selected for the anti-toxoplasmosis test in mice in vivo. Among the synthesized compounds, the (3R,5aS,6R,8aS,9R,12R,12aR)-3,6,9-trimethyl-decahydro-12H-3,12-epoxy[1,2]di-oxepino[4,3 -i]isochromen-10-yl-(te-rt-butoxycarbonyl)-L-alaninate (A2) exhibited the most potent anti-T. gondii activity and low cytotoxicity (SI: 6.44), yielding better results than the lead compound DHA (SI: 1.00) and the clinically used positive-control drug spiramycin (SI: 0.72) in vitro. Furthermore, compound A2 had better growth inhibitory effects on T. gondii in vivo than spiramycin did and significantly reduced the number of tachyzoites in the peritoneal cavity of mice (P 0.01). The evaluation of the data generated in the T. gondii mouse infection model indicates that compound A2 treatment was a good inhibitor of T. gondii in vivo and that it was effective in relieving the liver damage induced by T. gondii. In addition, the results of a docking study revealed that A2 could become a better T. gondii calcium-dependent protein kinase1 (TgCDPK1) inhibitor. For this reason, compound A2 has potential as an anti-parasitic drug. Further studies are required to elucidate the mechanism of the action of compound A2, as well as to develop drug delivery systems for patients.
Synthesis, antimicrobial potency with in silico study of Boc-leucine-1,2,3-triazoles
Ghule, Vikas D.,Kumar, Ashwani,Lal, Kashmiri,Naveen,Tittal, Ram Kumar,Yadav, Pinki
supporting information, (2020/07/02)
A library of N-Boc protected Leucine-linked 1,4-disubstituted 1,2,3-triazoles was synthesized and fully characterized, in high yield via copper-catalyzed alkyne-azide cycloaddition (CuAAC) reaction. In vitro antibacterial activity showed that compound 4h found to be more potent than the reference drug Ciprofloxacin (MIC: 0.0196 μmol/mL) against tested bacterial strains S. entrica, B. subtilis, S. aureus, E. coli and P. auroginosa with MIC: 0.0148, 0.0074, 0.0148, 0.0074, and 0.0074 μmol/mL, respectively and antifungal activity with MIC: 0.0148 μmol/mL as compared to reference drug Fluconazole (MIC: 0.0102 μmol/mL) against A. niger and C. albicans fungal strains. Further, the molecular docking study on 4h and its predecessor alkyne 3 by choosing E. coli topoisomerase II, DNA Gyrase (PDB ID: 1KZN) showed better binding with triazole than alkyne and these results were supported by DFT study using B3LYP/6-311G(d,p) basis set.
