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Search for "amino acid" in Full Text gives 550 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Tandem diazotization/cyclization approach for the synthesis of a fused 1,2,3-triazinone-furazan/furoxan heterocyclic system
Beilstein J. Org. Chem. 2024, 20, 2342–2348, doi:10.3762/bjoc.20.200
- , furoxancarboxamides 2f–h bearing aliphatic substituents or amino acid residues also smoothly underwent the studied tandem protocol and the corresponding biheterocyclic compounds 1f–h were obtained in yields of 45–77%. After having developed a general method for the synthesis of target furoxanotriazinones 1a–h, we
- found to be suitable for the preparation of a library of new biheterocyclic molecules bearing aromatic and aliphatic substituents as well as incorporating amino acid residues. The obtained furoxanotriazinones have demonstrated a moderate NO-releasing ability across a wide range of concentrations under
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
- and amino acid remain unknown. In contrast, the peptide-level identification is focused on the characterization of the actual probe-modified peptides. It might be more challenging as a larger protein amount to start with is necessary and the fragments of the probe-modified peptides may not be trivial
- , 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
Stereoselective mechanochemical synthesis of thiomalonate Michael adducts via iminium catalysis by chiral primary amines
Beilstein J. Org. Chem. 2024, 20, 2313–2322, doi:10.3762/bjoc.20.198
- planetary mill. Further variations of system A concerned the acid’s role. However, no impact of the acid was noted while using the amino acid derivative AC-2, but the dramatic loss of selectivity was observed in the case of chiral phosphoric acid’s application AC-3. Thus, it is rather unlikely the iminium
Deuterated reagents in multicomponent reactions to afford deuterium-labeled products
Beilstein J. Org. Chem. 2024, 20, 2270–2279, doi:10.3762/bjoc.20.195
- Strecker reaction [44][45] where a cyanide, aldehyde, and amine react to afford α-aminonitriles. Compound 5c was converted to the deuterated amino acid 5d under acidic conditions. This finding opens up the possibility of scale-production of deuterium-labeled α-amino acids. Deuterated Strecker products are
Cell-free protein synthesis with technical additives – expanding the parameter space of in vitro gene expression
Beilstein J. Org. Chem. 2024, 20, 2242–2253, doi:10.3762/bjoc.20.192
- used to establish a reference CFPS synthesis under standard conditions containing 2% PEG-8000. A concentration of 1.77 mg/mL sfGFP was obtained after 4 hours. The calculated fractional yield of 114% based on the added amino acid concentration is higher than expected, which can be explained either by
Computational toolbox for the analysis of protein–glycan interactions
Beilstein J. Org. Chem. 2024, 20, 2084–2107, doi:10.3762/bjoc.20.180
- -translational modifications, including glycosylation, in which a carbohydrate chain is directly attached to a specific amino acid to generate glycoproteins and proteoglycans [27]. Based on the amino acid involved in the link with the carbohydrates chain, it is possible to classify different types of
- its amino acid sequence and the structure of a related protein that is already known. However, also template-free PSP has obtained significant progress recently via machine learning and search-based optimisation approaches [87]. There are several software programs and tools available for homology
- effective drug design. Moreover, ab initio prediction of a protein's structure only from its amino acid sequence remains unsolved. Accessing Rosetta molecular modelling software tools (https://www.rosettacommons.org/software) has traditionally required expertise in the Unix command line environment
Negishi-coupling-enabled synthesis of α-heteroaryl-α-amino acid building blocks for DNA-encoded chemical library applications
Beilstein J. Org. Chem. 2024, 20, 1922–1932, doi:10.3762/bjoc.20.168
- applicable to a broad range of substrates, however, it utilizes a catalyst that is not commercially available and small heteroaromatic rings are underrepresented in the scope. Recognizing the importance of small heteroaromatic rings and the amino acid motif in medicinal chemistry [30][31][32][33], and aiming
Access to 2-oxoazetidine-3-carboxylic acid derivatives via thermal microwave-assisted Wolff rearrangement of 3-diazotetramic acids in the presence of nucleophiles
Beilstein J. Org. Chem. 2024, 20, 1894–1899, doi:10.3762/bjoc.20.164
- derivatives (mainly amides) exhibit various types of biological activity, among which the following can be highlighted: inhibition of β-lactamases [4][5], antitubercular properties [6], antiproliferative and antibacterial activity [7], herbicidal properties [8][9], inhibition of neutral amino acid transporter
2-Heteroarylethylamines in medicinal chemistry: a review of 2-phenethylamine satellite chemical space
Beilstein J. Org. Chem. 2024, 20, 1880–1893, doi:10.3762/bjoc.20.163
- -heteroarylethylamine chemical space is constituted by the biogenic amine histamine (43). In a similar fashion as dopamine and epinephrine produced from ʟ-phenylalanine along the catecholamine pathway, histamine is generated from the amino acid ʟ-histidine (42) via enzymatic decarboxylation promoted by ʟ-histidine
- diffusion features related to these changes. The amino acid ʟ-histidine has attracted the attention of the medicinal chemistry community due to its properties not only in the aforementioned histaminergic system, but also as metal-ion chelator, proton buffering modulator, and antioxidant. Considering the
- originally synthesized by Palazzo et al. [76] and several other derivatives were developed based on ethylamine-chain homologation [77]. Triazoles: Hall and co-workers [78] developed 1,2,3-triazolyl analogues 111 of ʟ-histidine for ʟ-type amino acid transporter 1 (LAT1) activity, a sodium-independent membrane
The Groebke–Blackburn–Bienaymé reaction in its maturity: innovation and improvements since its 21st birthday (2019–2023)
Beilstein J. Org. Chem. 2024, 20, 1839–1879, doi:10.3762/bjoc.20.162
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
- localize novel evolutive clades This study used 28 amino acid sequences of LanM enzymes from MIBiG [38] whose activity has been experimentally proven [24] to identify homologous sequences using BLASTP [39] (in BV-BRC [40]). They are considered our reference sequences. Two of these reference sequences are
- enzymes amino acid sequences from MIBiG and the homologs identified in our study. The taxonomy of the bacteria to which they belong is indicated in the figure. The selected superclade highlighted in Figure 1, containing sequences that mainly belong to Bacilli and Clostridia, was of particular interest
Syntheses and medicinal chemistry of spiro heterocyclic steroids
Beilstein J. Org. Chem. 2024, 20, 1713–1745, doi:10.3762/bjoc.20.152
Chemo-enzymatic total synthesis: current approaches toward the integration of chemical and enzymatic transformations
Beilstein J. Org. Chem. 2024, 20, 1693–1712, doi:10.3762/bjoc.20.151
- pentacyclic core scaffold of 5. Overall, the single NRPS module SfmC is responsible for the construction of the highly functionalized scaffold 93 from the two simple amino acid derivatives 86 and 88. After NRPS-catalyzed scaffold assembly, SfmM1-mediated N-methylation at N12, and subsequent SfmO2/O4-promoted
- synthesis of the bis-THIQ alkaloid family, Oguri and Oikawa utilized the NRPS module SfmC to construct a highly functionalized scaffold from amino acid derivatives (Scheme 10) [102]. The total synthesis of 5 from original biosynthetic intermediate 93 requires regioselective amide bond cleavage to remove the
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
- the specialised metabolism of bacteria and fungi. Each NRPS module is minimally composed of a condensation (C) domain, an adenylation (A) domain, and a peptidyl carrier protein (PCP or thiolation/T domain), and one module typically incorporates one amino acid into the final natural product. In
- [34]. In reductive amination, the substrate is usually an aldehyde or amine. After the formation of the iminium ion, it is reduced with the appropriate reagent to form the N-methylated amino acid. Different methods have been established using for example benzaldehyde as a protection group, sodium
- intermediate is then reduced with H2 [37]. When synthesising via a reductive ring opening, typically, an N-Fmoc-protected amino acid is condensed with formaldehyde in the presence of p-toluic acid in refluxing toluene to yield the 5-oxazolidinone. Reductive ring opening can be achieved by using an excess of
Mining raw plant transcriptomic data for new cyclopeptide alkaloids
Beilstein J. Org. Chem. 2024, 20, 1548–1559, doi:10.3762/bjoc.20.138
- biosynthetic enzymes. Ultimately proteolysis releases the modified core peptide as the mature RiPP natural product [5][6]. In the case of the newly described burpitide family of RiPPs, the defining feature is the presence of amino acid side-chain crosslinks installed by a copper-dependent burpitide cyclase [4
- ]. These RiPP natural products encompass a wide range of structural scaffolds including cyclopeptide alkaloids that contain a phenolic ether-linkage and the lyciumin-type peptides that are composed of a crosslink between the Trp-indole-N and the carbon in another amino acid side chain or peptide backbone
- were prepared to match the core amino acids of the predicted ceanothine B and CAM603 cyclopeptide alkaloids. To make each amino acid standard, 0.2 mg of the ʟ- and ᴅ-amino acid was aliquoted into separate reaction vials. To each vial, 50 µL of water, 20 µL of 1 M NaHCO3, and 100 µL 1% Marfey’s reagent
Benzylic C(sp3)–H fluorination
Beilstein J. Org. Chem. 2024, 20, 1527–1547, doi:10.3762/bjoc.20.137
- FAT with Selectfluor to produce the desired benzyl fluoride. Increasing amino acid and Selectfluor loadings achieved difluorination of the benzylic substrates. This procedure was demonstrated predominately on primary benzylic substrates, but could be used to effect the fluorination of several
- radical benzylic C(sp3)–H fluorination using Selectfluor. Silver and amino acid-mediated benzylic fluorination. Copper-catalysed radical benzylic C(sp3)–H fluorination using NFSI. Copper-catalysed C(sp3)–H fluorination of benzylic substrates with electrochemical catalyst regeneration. Yields are NMR
Towards an asymmetric β-selective addition of azlactones to allenoates
Beilstein J. Org. Chem. 2024, 20, 1504–1509, doi:10.3762/bjoc.20.134
- -selective manner with moderate levels of enantioselectivities (up to 83:17 er). Furthermore, the obtained products can be successfully engaged in nucleophilic ring opening reactions, thus giving highly functionalized α-amino acid derivatives. Keywords: allenoates; amino acids; azlactones; organocatalysis
- -functionalizations by reacting them with suited C- or heteroatom electrophiles. α-Amino acid-derived azlactones 1 are amongst the most commonly utilized starting materials to access more diverse chiral α,α-disubstituted amino acids (Scheme 1A) [20][21][22]. More specifically, these compounds can be engaged in a
- thus wondering if we could extend this ammonium salt-catalyzed β-selective allenoate functionalization strategy to other amino acid classes. Azlactones 1 have previously been used for γ-selective additions to allenoates under chiral phosphine catalysis [28]. In addition, glycine Schiff base derivatives
Bioinformatic prediction of the stereoselectivity of modular polyketide synthase: an update of the sequence motifs in ketoreductase domain
Beilstein J. Org. Chem. 2024, 20, 1476–1485, doi:10.3762/bjoc.20.131
- , deepening our understanding of the stereocontrol of PKSs. Results and Discussion Preparation of KR sequence dataset We first curated the amino acid sequences of KR domains from characterized bacterial cis-AT PKSs recorded in MIBiG database [20] and by manual literature review. In total, 1,762 KRs whose
- observed in the KRC tree of actinobacterial β-modules, we next carried out sequence logo analyses to identify key amino acid residues associated with stereoselectivity. Comparison of sequence logos among different types of KRCs revealed that the previously reported motifs [8][9], such as LDD (2) for B-type
- bioinformatics perspective, and will facilitate accurate stereochemical prediction and genome mining of complex polyketides. Experimental Sequence collection and screening All cis-AT PKS and PKS-NRPS amino acid sequences recorded in MIBiG, as well as the PKS sequences reported in literatures we have curated were
Novel analogues of a nonnucleoside SARS-CoV-2 RdRp inhibitor as potential antivirotics
Beilstein J. Org. Chem. 2024, 20, 1029–1036, doi:10.3762/bjoc.20.91
- ], and thus avoiding the use of base, leading to the desired intermediate 14 in good yield. Compound 14 was then coupled with ʟ-tyrosine methyl ester followed by deprotection of the amino acid carboxyl group by LiOH⋅H2O. As in the previous base-mediated saponification, here we also received a product of
- synthetic strategy leading to pyridones bearing different aryl substituents is described in Scheme 2. During the Suzuki–Miyaura cross-coupling reaction, which introduced the substituents in the C-5 position, the methyl ester protection of the amino acid moiety was also cleaved, leading directly to the final
Auxiliary strategy for the general and practical synthesis of diaryliodonium(III) salts with diverse organocarboxylate counterions
Beilstein J. Org. Chem. 2024, 20, 1020–1028, doi:10.3762/bjoc.20.90
- in organic chemistry and other scientific fields. The potential of diaryliodonium(III) carboxylates obtained in this study (i.e., Scheme 6B,C) and the related amino acid derivatives [46][47][48][49] as new arylating reagents will be further explored by conducting reactions with various nucleophiles
(Bio)isosteres of ortho- and meta-substituted benzenes
Beilstein J. Org. Chem. 2024, 20, 859–890, doi:10.3762/bjoc.20.78
- reduction. Deprotection of the alcohol followed by two-step oxidation to the carboxylic acid yielded the non-natural β-amino acid (±)-50, which could then be transformed into diamine (±)-51 by Curtius rearrangement. Recently, Mykhailiuk and co-workers also reported the synthesis of 1,2-BCHs using an
- , respectively (Scheme 12B) [58]. Saponification of the ester moieties in these species followed by Curtius rearrangements then led to amines 114 and 116. Non-natural amino acid derivatives 113 and 117 are intermediates prepared using these methods that could be of interest to medicinal chemistry. Alcohol 111
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
- physiological function of NNG are discussed below. Results Screening of Vs NnlA homologs for NNG degradation activity To select Vs NnlA homologs to test for NNG degradation activity, we performed a BLAST search of the Vs NnlA amino acid sequence in the NCBI database. This search resulted in retrieval of 99
- homologous amino acid sequences with an E-value of less than 1 × 10−10. A subset of 55 of these sequences was selected with a query cover of greater than 88%. From these sequences, we selected five homologs of the nnlA gene [Pseudovibrio denitrificans JCM 1230 (Pd), Pseudovibrio japonicus strain KCTC 12861
- (Pj), Pseudonocardia spinosispora DSM 44797 (Ps), Mycobacterium sp. 1465703.0 (Ms), Microbispora rosea subsp. nonnitritogenes strain NRRL B-2631 (Mr)], which were synthesized and cloned into E. coli recombinant expression vectors. These homologs ranged in amino acid sequence identity from 46 to 76
Synthesis and characterization of water-soluble C60–peptide conjugates
Beilstein J. Org. Chem. 2024, 20, 777–786, doi:10.3762/bjoc.20.71
- 1). Results and Discussion Syntheses of C60–oligopeptides 5a–c The oligopeptides 2a–c were synthesized on resin using Fmoc-protected amino acids with a standard SPPS method (Figure 1a) [43]. A moderate loading (0.4 mmol⋅g−1) of the initial amino acid was used. After synthesizing the pentamer of Lys
- acid-substituted C60 derivative 3 and the peptides on resin 2a–c were performed by SPPS to provide the C60–oligopeptides on resin 4a–c (Figure 1a). Subsequently, the last step of the reaction – the cleavage of the C60–peptide conjugate from the resin and the simultaneous deprotection of the amino acid
- the C60–peptide conjugates on resin 4a–c from 2a–c. The C60–oligopeptides 5a–c were obtained by cleavage from resin and simultaneous deprotection of the PGs on the amino acid side chains through the addition of by the addition of a mixture of TFA and TIPS in water. The most soluble conjugate, C60
Substrate specificity of a ketosynthase domain involved in bacillaene biosynthesis
Beilstein J. Org. Chem. 2024, 20, 734–740, doi:10.3762/bjoc.20.67
- understanding of polyketide biosynthesis has been reached, including a detailed knowledge of the extender unit selection and the stereochemical implications that are predictable from amino acid sequences [5][6]. The polyene antibiotic bacillaene was first isolated from Bacillus subtilis [7]. This soil-dwelling
- , showing that the amino acid sequences of these KSs correlate with the structures of the processed PKS intermediates up to the β-carbon [20]. 13C NMR spectra of (R)-11 incubated with BaeJ-KS2 and BaeJ-KS2-C222A. A) Free 11 dissolved in incubation buffer; B) (R)-11 bound to BaeJ-KS2 after incubation and
Chemoenzymatic synthesis of macrocyclic peptides and polyketides via thioesterase-catalyzed macrocyclization
Beilstein J. Org. Chem. 2024, 20, 721–733, doi:10.3762/bjoc.20.66
- several positions and also form 6–14 residue cyclic peptides [37][38]. It should be noted that TycC TE was more sensitive to the amino acid changes near the site of ring closure. The alkyne-containing analogs were conjugated to a variety of azido sugars via copper(I)-catalyzed cycloaddition to obtain the
- developed to address this challenge to produce daptomycin and its derivatives. These approaches include biosynthetic [49], chemoenzymatic [50], solid-phase [51], and solution-phase methods [52], but most only encompass modifications of the lipid chain and specific amino acid mutations. Learning from the
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