68858-20-8Relevant articles and documents
Self-assembly and anion-response of azobenzene-based L-valinamide derivative
Li, Kechang,Xue, Pengchong
, p. 206 - 212 (2018)
An azobenzene-based L-valinamide derivative was synthesized, and its gelation ability and self-assembly in organic solvents were investigated. Results suggested that it is an excellent gelator and formed organogels in many solvents, such as 3-pentanone, aniline, o-dichlorobenzene (ODCB), CH2Cl2, THF, ethanol, DMSO, and DMF. Its self-assembly in ODCB gel was studied. Transmission electron microscopic observation suggested that the gelator can self-assemble into one-dimensional nanofibers in the gel, and this phenomenon is driven by hydrogen bonding between amide units and π-π interaction between azobenzene moieties. With the increase in gelator concentration, the gel-to-sol phase transition temperature increased and the gelation time of the solvent shortened. Moreover, the gel exhibit anion response. A gel-to-sol phase transition was found after fluoride anion was added, exhibiting selective response to F?.
Fungal Dioxygenase AsqJ Is Promiscuous and Bimodal: Substrate-Directed Formation of Quinolones versus Quinazolinones
Einsiedler, Manuel,Jamieson, Cooper S.,Maskeri, Mark A.,Houk, Kendall N.,Gulder, Tobias A. M.
supporting information, p. 8297 - 8302 (2021/03/01)
Previous studies showed that the FeII/α-ketoglutarate dependent dioxygenase AsqJ induces a skeletal rearrangement in viridicatin biosynthesis in Aspergillus nidulans, generating a quinolone scaffold from benzo[1,4]diazepine-2,5-dione substrates. We report that AsqJ catalyzes an additional, entirely different reaction, simply by a change in substituent in the benzodiazepinedione substrate. This new mechanism is established by substrate screening, application of functional probes, and computational analysis. AsqJ excises H2CO from the heterocyclic ring structure of suitable benzo[1,4]diazepine-2,5-dione substrates to generate quinazolinones. This novel AsqJ catalysis pathway is governed by a single substituent within the complex substrate. This unique substrate-directed reactivity of AsqJ enables the targeted biocatalytic generation of either quinolones or quinazolinones, two alkaloid frameworks of exceptional biomedical relevance.
COMPOUNDS, COMPOSITIONS, METHODS, AND USES FOR TREATING CANCER AND IMMUNOLOGICAL DISORDERS
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Paragraph 0546; 0551-0552, (2020/02/06)
The present disclosure provides novel polypeptide-therapeutic compound or hormone-therapeutic compound conjugates using cleavable or non-cleavable linkers, whereby the polypeptide or hormone serves to target specific cells using receptor expression on the targeted cell to bind the ligand (polypeptide or hormone) carrying the therapeutic compound unlike antibody drug conjugates. Upon binding, the ligand and the therapeutic compound (multiples of the therapeutic compound in some embodiments) enter the cell by receptor-mediated endocytosis, and release drugs conjugated to the ligand by linkers, to interact with intracellular components to enhance, restore, or block a signal transduction process. The ligands for the polypeptide-therapeutic compound or hormone-therapeutic compound conjugates include, but are not limited to: cytokines, growth factors and hormones among other proteins with corresponding cell surface specific receptors. The disorders targeted by such polypeptide-therapeutic compound or hormone-therapeutic compound conjugates include, but are not limited to: immunological disorders (e.g., allergy and autoimmune disorders) and cancer.
Novel chiral stationary phases based on 3,5-dimethyl phenylcarbamoylated β-cyclodextrin combining cinchona alkaloid moiety
Zhu, Lunan,Zhu, Junchen,Sun, Xiaotong,Wu, Yaling,Wang, Huiying,Cheng, Lingping,Shen, Jiawei,Ke, Yanxiong
, p. 1080 - 1090 (2020/05/25)
Novel chiral selectors based on 3,5-dimethyl phenylcarbamoylated β-cyclodextrin connecting quinine (QN) or quinidine (QD) moiety were synthesized and immobilized on silica gel. Their chromatographic performances were investigated by comparing to the 3,5-dimethyl phenylcarbamoylated β-cyclodextrin (β-CD) chiral stationary phase (CSP) and 9-O-(tert-butylcarbamoyl)-QN-based CSP (QN-AX). Fmoc-protected amino acids, chiral drug cloprostenol (which has been successfully employed in veterinary medicine), and neutral chiral analytes were evaluated on CSPs, and the results showed that the novel CSPs characterized as both enantioseparation capabilities of CD-based CSP and QN/QD-based CSPs have broader application range than β-CD-based CSP or QN/QD-based CSPs. It was found that QN/QD moieties play a dominant role in the overall enantioseparation process of Fmoc-amino acids accompanied by the synergistic effect of β-CD moiety, which lead to the different enantioseparation of β-CD-QN-based CSP and β-CD-QD-based CSP. Furthermore, new CSPs retain extraordinary enantioseparation of cyclodextrin-based CSP for some neutral analytes on normal phase and even exhibit better enantioseparation than the corresponding β-CD-based CSP for certain samples.
Determination of Chemical and Enantiomeric Purity of α-Amino Acids and their Methyl Esters as N-Fluorenylmethoxycarbonyl Derivatives Using Amylose-derived Chiral Stationary Phases
Islam, Md. Fokhrul,Adhikari, Suraj,Paik, Man-Jeong,Lee, Wonjae
, p. 332 - 338 (2019/04/13)
Liquid chromatographic enantiomer separation and simultaneous determination of chemical and enantiomeric purity of α-amino acids and their methyl esters as N-fluorenylmethoxycarbonyl (FMOC) derivatives was performed on three covalently bonded type chiral stationary phases (CSPs) derived from amylose derivatives. The enantiomer separation of α-amino acid esters as N-FMOC derivatives was better than that of the corresponding acids, especially for CSP 1 and 2. Chemical impurities as the corresponding racemic acids present in several commercially available racemic amino acid methyl esters were observed to be 0.49–17.50%. Enantiomeric impurities of several commercially available L-amino acid methyl esters were found to be 0.03–0.58%, whereas chemical impurities as the corresponding racemic acids present in the same analytes were found to be 0.13–13.62%. This developed analytical method will be useful for the determination of chemical and enantiomeric purity of α-amino acids and/or esters as N-FMOC derivatives using amylose-derived CSPs.
Unwanted hydrolysis or α/β-peptide bond formation: How long should the rate-limiting coupling step take?
Goldschmidt G?z, Viktória,Nagy, Adrienn,Farkas, Viktor,Keszei, Ern?,Perczel, András
, p. 30720 - 30728 (2019/10/28)
Nowadays, in Solid Phase Peptide Synthesis (SPPS), being either manual, automated, continuous flow or microwave-assisted, the reaction with various coupling reagents takes place via in situ active ester formation. In this study, the formation and stability of these key active esters were investigated with time-resolved 1H NMR by using the common PyBOP/DIEA and HOBt/DIC coupling reagents for both α- and β-amino acids. Parallel to the amide bond formation, the hydrolysis of the α/β-active esters, a side reaction that is a considerable efficacy limiting factor, was studied. Based on the chemical nature/constitution of the active esters, three amino acid categories were determined: (i) the rapidly hydrolyzing ones (t 24 h) in solution. The current insight into the kinetics of this key hydrolysis side reaction serves as a guide to optimize the coupling conditions of α- and β-amino acids, thereby saving time and minimizing the amounts of reagents and amino acids to be used-all key factors of more environmentally friendly chemistry.
Chiral oxazoline NNP type ligands as well as synthesis method and application thereof
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Paragraph 0092; 0093; 0094; 0095, (2017/08/28)
The invention relates to chiral oxazoline NNP type ligands as well as a synthesis method and an application thereof. The ligands adopt the structure shown in general formula 1 or 2. During preparation, a chiral ligand 1 and a chiral ligand 2 are prepared from Fmoc-Cl and a chiral amino acid compound 3 used as initial raw materials through multi-step reactions. The ligands can be applied to catalytic synthesis of chiral beta ketone ester fluoride and synthesis of propanedione derivatives and chiral malonate derivatives through palladium-catalyzed asymmetric allyl substitution reactions. Compared with the prior art, the reaction condition is mild, operation is easy, repeatability is good, mass preparation can be realized, and the prepared catalyst has higher ee value and yield when applied to beta ketone ester fluoridation and palladium-catalyzed asymmetric allyl substitution reactions.
Fmoc-Amox, A Suitable Reagent for the Introduction of Fmoc
Kumar, Ashish,Sharma, Anamika,Haimov, Elvira,El-Faham, Ayman,De La Torre, Beatriz G.,Albericio, Fernando
, p. 1533 - 1541 (2017/10/25)
Synthesis of most peptides is achieved using solid-phase peptide synthesis employing the Fmoc/tert-butyl strategy. However, the introduction of Fmoc in N-unprotected amino acids seems to be challenging due to the formation of dipeptides and sometimes tripeptides as impurities and β-alanyl impurities when Fmoc-OSu is used as well. Herein, we report an efficient and successful method using Fmoc-Amox, which is an oxime based derivative, toward the synthesis of Fmoc-glycine with no traces of side reactions. Fmoc-Amox is inexpensive, and Amox can be easily removed after the reaction, thus affording pure Fmoc-Gly-OH devoid of any detrimental impurities or contamination, mainly dipeptide or Amox itself, as shown by high-performance liquid chromatography and NMR, respectively.
Fmoc-OPhth, the reagent of Fmoc protection
Yoshino, Ryo,Tokairin, Yoshinori,Kikuchi, Mari,Konno, Hiroyuki
supporting information, p. 1600 - 1603 (2017/04/03)
Fmoc-OSu has been widely used for Fmoc protection of amino groups, especially amino acids, in solid phase peptide synthesis. However, it has been recognized that Fmoc-βAla-OH is formed as a by-product via the Lossen rearrangement during the reaction. Since we reconfirmed the formation of Fmoc-βAla-OH during the preparation of Fmoc-AA-OH by Fmoc-OSu, Fmoc-OPhth was designed and synthesized as a new Fmoc reagent to avoid the formation of Fmoc-βAla-OH. Furthermore, Fmoc protection by Fmoc-OPhth and Fmoc-SPPS were evaluated. The various Fmoc-amino acids prepared by Fmoc-OPhth were carried out in good yields and these are applicable in Fmoc-SPPS.
Total Synthesis and Biological Evaluation of Natural and Designed Tubulysins
Nicolaou,Yin, Jun,Mandal, Debashis,Erande, Rohan D.,Klahn, Philipp,Jin, Michael,Aujay, Monette,Sandoval, Joseph,Gavrilyuk, Julia,Vourloumis, Dionisios
supporting information, p. 1698 - 1708 (2016/02/20)
A streamlined total synthesis of N14-desacetoxytubulysin H (Tb1) based on a C-H activation strategy and a short total synthesis of pretubulysin D (PTb-D43) are described. Applications of the developed synthetic strategies and technologies to the synthesis of a series of tubulysin analogues (Tb2-Tb41 and PTb-D42) are also reported. Biological evaluation of the synthesized compounds against an array of cancer cells revealed a number of novel analogues (e.g., Tb14), some with exceptional potencies against certain cell lines [e.g., Tb32 with IC50 = 12 pM against MES SA (uterine sarcoma) cell line and 2 pM against HEK 293T (human embryonic kidney) cell line], and a set of valuable structure-activity relationships. The highly potent cytotoxic compounds discovered in this study are highly desirable as payloads for antibody-drug conjugates and other drug delivery systems for personalized targeted cancer chemotherapies.
