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Search for "cysteine" in Full Text gives 122 result(s) in Beilstein Journal of Organic Chemistry.
Recent advances in transition-metal-free arylation reactions involving hypervalent iodine salts
Beilstein J. Org. Chem. 2024, 20, 2891–2920, doi:10.3762/bjoc.20.243
- therapeutics, particularly in antibody–drug conjugates (ADCs). Cysteine (Cys) holds a special place in this context due to the distinctive nucleophilicity of its thiol side chain. The cysteine thiol group offers a reactive handle for site-selective modifications, allowing for the attachment of various
- functional entities. In 2021, Byrne et al. published an impressive report detailing a novel protocol for the chemoselective late-stage variation of proteins and peptides at cysteine residues 91 and 94 in an aqueous buffer in the presence of suitably functionalized diaryliodonium salts 92 and 95 (Scheme 38
Improved deconvolution of natural products’ protein targets using diagnostic ions from chemical proteomics linkers
Beilstein J. Org. Chem. 2024, 20, 2323–2341, doi:10.3762/bjoc.20.199
- by high percentage of organic solvent, for example 80% acetonitrile. Yan et al. showed that such biotin–probe–peptides afforded characteristic fragmentation of the biotin linker, thus improving the identification of probe–peptide conjugates in cysteine-profiling experiments [102]. The biotin linker
- ion was the dehydrobiotin ion with occurrence in >80% of the spectra. The detailed list of all identified biotin and cysteine reactive probe related ions can be found in reference [102]. A plethora of biotin–azide linkers is commercially available, with the main difference lying in the length or
- , in this case, the cysteine thiols were derivatized and the cysteine C–S bond was previously described to be susceptible to fragmentation, the fragments containing the thiol provide the information on the structure of the modified amino acid side chain [107][108]. Although the study was focused on the
Discovery of antimicrobial peptides clostrisin and cellulosin from Clostridium: insights into their structures, co-localized biosynthetic gene clusters, and antibiotic activity
Beilstein J. Org. Chem. 2024, 20, 1800–1816, doi:10.3762/bjoc.20.159
- resulting peptides exhibit unique structural features due to thioether bridges between dehydrated serine or threonine (Dha/Dhb) and cysteine (Cys). These thioether bridges lead to cyclic peptides with the modified amino acid lanthionine (Dha-Cys) or methyllanthionine (Dhb-Cys). The strong antimicrobial
- times dehydrated was identified. Cyclization reactions introduced thioether cross-links between dehydrated Thr/Ser residues and specific cysteine thiol groups. However, due to identical masses of dehydrated linear peptides (lacking thioether rings) and cyclic forms (containing Dhb and Dha rings), a
- of 57u due to cysteine alkylation (Figure 4C and Table S8 in Supporting Information File 1). These analyses confirm the activity of the CloM2 enzyme, with the dehydratase domain activity forming a mixture of six and five times dehydrated lantipeptides, and the cyclase domain activity demonstrated by
Methyltransferases from RiPP pathways: shaping the landscape of natural product chemistry
Beilstein J. Org. Chem. 2024, 20, 1652–1670, doi:10.3762/bjoc.20.147
- involved in RiPP maturation, all C-MTs described in the following section are classified as rSAM C-MTs. Radical SAM C-methyltransferases Radical SAM enzymes typically contain a conserved CxxxCxxC motif. The cysteine residues of this motif coordinate a [4Fe-4S] cluster. rSAM MTs can be classified based on
- factor. The MT PtyS is part of a proteusin BGC pty and catalyses the S-methylation of up to four out of five cysteine residues in the precursor PtyA. In heterologous co-expressions of PtyA and PtyS, methylations were localised via LC–MS analysis to Cys9 and Cys15, with Cys9 being the preferred target. In
- the heterologous expression system, S-methylation of the cysteine residues can co-occur with lanthionine formation. When PtyM and PtyS are co-expressed, only one methylation of cysteine and three dehydrations could be observed. This may be due to the installed modifications inhibiting each other or
Activity assays of NnlA homologs suggest the natural product N-nitroglycine is degraded by diverse bacteria
Beilstein J. Org. Chem. 2024, 20, 830–840, doi:10.3762/bjoc.20.75
- formation of propionate 3-nitronate (P3N) as a conjugate base (Scheme 2) [39]. It is P3N that directly reacts with a cysteine in the ICL1 active site, forming a thiohydroxamate adduct that inhibits ICL1 turnover [40]. Additionally, the nitronate form of nitro acids has been proposed to behave as a
Synthesis of new representatives of A3B-type carboranylporphyrins based on meso-tetra(pentafluorophenyl)porphyrin transformations
Beilstein J. Org. Chem. 2024, 20, 767–776, doi:10.3762/bjoc.20.70
- has become one of the most popular route for the site-selective modification of cysteine residues in bioconjugation technology. We suppose that the maleimide group in porphyrin 11 is a useful target for thiol conjugation via Michael addition reactions [44]. This also concerns biotin-conjugated organic
- cytoprotective and therapeutic actions. It is synthesized from cysteine and is excreted without any further metabolism [47]. The reaction of taurine (25) with porphyrin 6 proceeded in DMSO at 20 °C for 72 h to afford taurine-containing conjugate 26 in 78% yield (Scheme 6). Conjugates 19, 23, 24, and 26 can be
Switchable molecular tweezers: design and applications
Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45
Green and sustainable approaches for the Friedel–Crafts reaction between aldehydes and indoles
Beilstein J. Org. Chem. 2024, 20, 379–426, doi:10.3762/bjoc.20.36
- inspired by the use of ʟ-proline-modified magnetic nanoparticles reported by Khalafi-Nezhad et al., synthesized nano-Fe3O4@ʟ-cysteine for the green synthesis of BIMs, employing microwave irradiation to avoid long reaction times [117]. A mixture of the reagents and 100 mg of nano-Fe3O4@ʟ-cysteine per 1
- the nano-Fe3O4@ʟ-cysteine particles being magnetically recoverable in a facile manner. The reaction could also be realized with conventional heating at 80 °C, however, the reaction rates were more than 20 times lower, and ketones displayed unappealing conversion rates. The mechanism of action follows
Decarboxylative 1,3-dipolar cycloaddition of amino acids for the synthesis of heterocyclic compounds
Beilstein J. Org. Chem. 2023, 19, 1677–1693, doi:10.3762/bjoc.19.123
- 6) [75]. One-pot double annulations for the synthesis of tetrahydropyrrolothiazoles The unique tetrahydropyrrolothiazole and spiro[indole-tetrahydropyrrolothiazole] scaffolds are found in bioactive compounds such as those shown in Figure 7 [76][77]. Using cysteine as a key reactant, we developed a
- pseudo-four-component reaction for the synthesis of tetrahydropyrrolothiazole derivatives. The reaction of cysteine with two equiv of arylaldehydes and one equiv of maleimides in EtOH at 90 °C for 12 h afforded tetrahydropyrrolothiazoles 29 in 66–79% yields with up to 7:1 dr (Scheme 17) [76]. Using
- olefinic oxindoles to replace maleimides, the reactions gave spiro[indoline-tetrahydropyrrolothiazole] products 30 in 55–70% with greater than 4:1 dr [76]. The reaction mechanism suggests that the reaction of cysteine with arylaldehydes gives N,S-acetals 27 which convert to AMYs 28 after decarboxlyation
Sulfur-containing spiroketals from Breynia disticha and evaluations of their anti-inflammatory effect
Beilstein J. Org. Chem. 2023, 19, 1604–1614, doi:10.3762/bjoc.19.117
- electrospray ionization HRESIMS analysis, and quantum chemical electronic CD calculations. Furthermore, the absolute configurations of sugar residues were determined by derivatization of the hydrolysates with ʟ-cysteine methyl ester and o-tolyl isothiocyanate followed by HPLC analysis. The anti-inflammatory
- by acid hydrolysis of 1 using the method developed by Tanaka et al. [16], in which the hydrolysates are derivatized with ʟ-cysteine methyl ester and o-tolyl isothiocyanate followed by HPLC analysis. For compound 1, peaks were observed at retention times of 13.96, 20.83, and 22.16 min. The peaks at
- residue was added a solution of ʟ-cysteine methyl ester hydrochloride (2 mg) in pyridine (200 μL), and the mixture was stirred at 65 °C for 1 h. Then, a solution of o-tolyl isothiocyanate (2.2 μL) in pyridine (200 μL) was added and the resulting mixture was stirred at 65 °C for 1 h. The final mixture was
Enabling artificial photosynthesis systems with molecular recycling: A review of photo- and electrochemical methods for regenerating organic sacrificial electron donors
Beilstein J. Org. Chem. 2023, 19, 1198–1215, doi:10.3762/bjoc.19.88
Intermediates and shunt products of massiliachelin biosynthesis in Massilia sp. NR 4-1
Beilstein J. Org. Chem. 2023, 19, 909–917, doi:10.3762/bjoc.19.69
- 4), the biosynthesis starts from hexanoic acid which, upon its thioesterification, is elongated by three decarboxylative Claisen condensations with malonyl-CoA to a 6-pentylsalicyl thioester. A condensation with cysteine and a subsequent cyclization generate a 6-pentylsalicyl-thiazolinyl thioester
- intermediate (1’). In massiliachelin biosynthesis this intermediate is further processed and elongated with another cysteine-derived thiazoline, which is eventually reduced [18]. A premature hydrolytic release of 1’ from the assembly line would give 1, which could be further modified to 2–5. Some corresponding
A new oxidatively stable ligand for the chiral functionalization of amino acids in Ni(II)–Schiff base complexes
Beilstein J. Org. Chem. 2023, 19, 566–574, doi:10.3762/bjoc.19.41
- complex. Solubility of the t-Bu-containing ligand and its Schiff base complexes is increased, facilitating scaling-up the reaction procedure and isolation of the functionalized amino acid. Keywords: asymmetric synthesis; chiral auxiliaries; cysteine derivatives; Ni–Schiff base complexes; voltammetry
- . Results and Discussion Synthesis The synthetic approach to the chiral ligand L7 as well as to its Ni–Schiff base derivatives containing glycine, serine, dehydroalanine, and cysteine is given in Scheme 2. Commercially available (S)-proline was used as the starting material. To obtain the starting t-Bu
- techniques; for details, see Supporting Information File 1); [α]D20 = 2127 (MeOH). To test the stereocontrolling efficiency of the new ligand L7 and to obtain new cysteine Ni–Schiff base derivatives (RCysNi)L7 which are of practical interest, complex (ΔAlaNi)L7 was involved in a nucleophilic addition as
Dipeptide analogues of fluorinated aminophosphonic acid sodium salts as moderate competitive inhibitors of cathepsin C
Beilstein J. Org. Chem. 2023, 19, 434–439, doi:10.3762/bjoc.19.33
- development of fluorinated aminophosphonate-based inhibitors. Keywords: aminophosphonates; cathepsin C; dipeptide; fluorine; solvolysis; Introduction Cathepsin C, also known as dipeptidyl peptidase I (DPPI) belongs to the family of lysosomal cysteine proteases encompassing 11 human enzymes (cathepsins B, C
- in chemotherapies to support traditional anticancer drugs. Moreover, there is a growing interest in the topic of cathepsin C inhibition, which directly affects serine protease activity [5][6]. Inhibitors of cathepsin C can be cystatins that show activity against a large group of cysteine proteases [7
- the catalytic cysteine Cys234 [10]. Phosphonates, as well as their analogues phosphonic acids, can be modified in a number of ways, one of which is the introduction of a fluorine atom into their molecules by fluorination or alkylfluorination [11][12][13][14]. However, the reaction of β-aminoalcohols
Asymmetric synthesis of a stereopentade fragment toward latrunculins
Beilstein J. Org. Chem. 2023, 19, 428–433, doi:10.3762/bjoc.19.32
- of an unsaturated fourteen- or sixteen-membered macrolactone decorated by an ʟ-cysteine-derived 2-oxo-1,3-thiazolidin-4-yl substitutent, and the presence of five stereogenic centers forming a 1,2,4,6,9-stereopentade (Figure 1). In latrunculins A (1) and B (2) three of them are embedded in a lactol
- (13,14)-bond of 1 and 2, respectively. Conversely, we envisaged an alternative disconnection to form the (16,17)- or the (14,15)-bond of 1 and 2, through an aldol reaction of aldehyde 8 readily available from ʟ-cysteine, leading to aldol adduct 7 (Figure 2, route B). The methyl ketone partner 9 could be
- partner (8) for the aldol reaction brings the thiazolidinone heterocycle of the natural product. It was synthesized in four steps from ʟ-cysteine ester derivative 16, first reacting with carbonyldiimidazole (CDI) to afford thiazolidinone 17 in 85% yield (Scheme 2). The nitrogen atom was protected with a
One-pot double annulations to confer diastereoselective spirooxindolepyrrolothiazoles
Beilstein J. Org. Chem. 2022, 18, 1607–1616, doi:10.3762/bjoc.18.171
- 10.3762/bjoc.18.171 Abstract A novel four-component reaction in one pot as an atom- and step-economic process was developed to synthesize diastereoselectively spirooxindolepyrrolothiazoles through sequential N,S-acetalation of aldehydes with cysteine and decarboxylative [3 + 2] cycloaddition with olefinic
- PASE reactions of making spirooxindolepyrrolothiazoles are even more rare, which only involves three-component reactions with isatins and thioproline (Scheme 2A and 2B) [75][76]. Four-component double annulations through 2-substituted thioprolines formed in N,S-acetalation of aldehyde and cysteine was
- 2C). Results and Discussion The optimized reaction conditions of stepwise, one-pot and cascade (two-step with one operational step) processes for N,S-acetalation and decarboxylative 1,3-dipolar cycloaddition were developed by using two equivalents of 4-bromobenzaldehyde (1a), ʟ-cysteine (2) and
Microelectrode arrays, electrosynthesis, and the optimization of signaling on an inert, stable surface
Beilstein J. Org. Chem. 2022, 18, 1488–1498, doi:10.3762/bjoc.18.156
- array, a scenario that would make it unavailable for binding to the integrin receptor in the subsequent analytical experiment. The PEG-6-linker was selected because it was effective and readily available from commercial sources. This linker was functionalized with a cysteine on the end opposite the
- used for the placement reaction, the full binding curve for the interaction between R6A and its Gαi1-target could not be observed. A method was needed to further reduce the concentration of the R6A peptide on the surface of the electrodes. To this end, cysteine methyl ester was selected as a molecule
- with which to dilute the R6A peptide because cysteine methyl ester does not show any background binding to Gαi1, and it can be efficiently placed onto the arylbromide-based surface using the same Cu(I)-catalyzed cross-coupling reaction used to place the R6A-PEG-C substrate on the array (Scheme 3). The
Synthesis of C6-modified mannose 1-phosphates and evaluation of derived sugar nucleotides against GDP-mannose dehydrogenase
Beilstein J. Org. Chem. 2022, 18, 1379–1384, doi:10.3762/bjoc.18.142
- enzymatic coupling to complete the sugar nucleotide [7][8]. With this capability in place, we wished to explore the synthesis of further tools, targeting the active site cysteine residue (Figure 1c). We envisaged that access to C6–amino or C6–sulfhydryl species of type 8 would offer prospect to establish
- active site thiohemiaminal (amine to imine oxidation) or disulfide formation, respectively. Additionally, C6–Cl derivative 9 could probe cysteine alkylation. Reported herein is our exploration of this synthesis and the evaluation of GDP 6-chloro-6-deoxy-ᴅ-mannose 18 against GMD. Results and Discussion
Cytochrome P450 monooxygenase-mediated tailoring of triterpenoids and steroids in plants
Beilstein J. Org. Chem. 2022, 18, 1289–1310, doi:10.3762/bjoc.18.135
- system as well as a cysteine thiolate ligand from the protein backbone (Figure 1B). The generally accepted catalytic cycle for hydroxylations is shown in Figure 1C. In the resting state A, the central ferric ion is coordinated by six ligands, four from the porphyrin ring system, one cysteine thiolate
Polymer and small molecule mechanochemistry: closer than ever
Beilstein J. Org. Chem. 2022, 18, 1225–1235, doi:10.3762/bjoc.18.128
- the covalent capsule 5 (made from resorcinarene caps connected by four dihydrazone units of ʟ-cysteine) with C60 and C70 fullerenes upon neat ball milling in a planetary ball mill (Figure 6). The mechanochemical complexation is remarkable since the porous capsule does not possess large enough openings
Reductive opening of a cyclopropane ring in the Ni(II) coordination environment: a route to functionalized dehydroalanine and cysteine derivatives
Beilstein J. Org. Chem. 2022, 18, 1166–1176, doi:10.3762/bjoc.18.121
- acids. One-pot combination of the reductive ring opening and subsequent addition of thiols allows obtaining the cysteine derivatives in practical yields and with high stereoselectivity at the removed β-stereocenter. Keywords: amino acids; cathodic cyclopropane opening; cysteine derivatives; Ni–Schiff
- cyclopropane ring in α,α-cyclopropanated amino acids yielding the cysteine derivatives in practical yields and with high stereoselectivity at the removed β-stereocenter. Thus, the present paper is a further development of the extended research on electrochemically induced stereoselective transformations in the
- , alanine, serine and cysteine derivatives are formed as an antibonding combination of the Ni dx²-y² orbital with the group orbitals of the ligands; the π* orbital of the imine and the π orbital of the phenylene fragments are also partially involved. Reduction occurs at similar potential values and is
Terpenoids from Glechoma hederacea var. longituba and their biological activities
Beilstein J. Org. Chem. 2022, 18, 555–566, doi:10.3762/bjoc.18.58
- hydrolysis, was dissolved in pyridine (0.5 mL), then ʟ-cysteine methyl ester hydrochloride (2 mg) was added. The reaction mixture was stirred at 60 °C for 1 h. Then O-tolyl isothiocyanate (30 μL) was added and stirred at 60 °C for 1 h. The reaction mixture was analyzed without purification by LC–MS analysis
- using GC–MS. Monosaccharides (1, 0.4 mg; 2, 0.3 mg; 3, 0.4 mg; 4, 0.4 mg), obtained by hydrolysis, were dissolved in pyridine (0.5 mL), then ʟ-cysteine methyl ester hydrochloride (2 mg) was added. The reaction mixtures were then stirred at 60 °C for 2 h. After adding 1-trimethylsilylimidazole (0.1 mL
Menadione: a platform and a target to valuable compounds synthesis
Beilstein J. Org. Chem. 2022, 18, 381–419, doi:10.3762/bjoc.18.43
Glycosylated coumarins, flavonoids, lignans and phenylpropanoids from Wikstroemia nutans and their biological activities
Beilstein J. Org. Chem. 2022, 18, 200–207, doi:10.3762/bjoc.18.23
- and sugar, respectively. The aqueous residue was concentrated to dryness under N2. The aqueous residue, ᴅ-glucose (2 mg), and ᴅ-xylose standard (2 mg) were separately dissolved in 0.5 mL anhydrous pyridine, and ʟ-cysteine methyl ester hydrochloride (2.0 mg) was then added. Each reaction mixture was
Peptide stapling by late-stage Suzuki–Miyaura cross-coupling
Beilstein J. Org. Chem. 2022, 18, 1–12, doi:10.3762/bjoc.18.1
- of biomolecules [35][36][37]. The approaches by Buchwald and Pentelute are suitable for selective, bioorthogonal labelling of cysteine- [38][39][40] and lysine-containing [41][42] peptides and proteins using stochiometric amounts of pre-formed Pd(II)-aryl complexes. They can further be applied for
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