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Search for "methylation" in Full Text gives 270 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

New synthesis of a late-stage tetracyclic key intermediate of lumateperone

  • Mátyás Milen,
  • Bálint Nyulasi,
  • Tamás Nagy,
  • Gyula Simig and
  • Balázs Volk

Beilstein J. Org. Chem. 2022, 18, 653–659, doi:10.3762/bjoc.18.66

Graphical Abstract
  • to the hydrazine derivative 4, followed by a Fischer indole synthesis with ethyl 4-oxopiperidine-1-carboxylate (5) provided tetracyclic compound 6. Its reduction with sodium cyanoborohydride in trifluoroacetic acid (TFA) to cis-indoline derivative (±)-7, followed by N-methylation [(±)-8] and
  • reaction steps [8][9][10], e.g., because of the use of chloroacetamide instead of N-methylchloroacetamide, necessitating an additional N-methylation. The tetracycle 8 was finally subjected to the same reaction sequence as the corresponding racemate (see also Scheme 1), lumateperone (1) was thus prepared
  • , which would have been based on the 1-methyl-4-amino-1,2,3,4-tetrahydroquinoxaline (23) intermediate (Scheme 4). We planned to convert the latter into (±)-9a via compound 22a by known methods. The synthesis of compound 23 was attempted as follows. N-Methylation of quinoxaline (24) with methyl p
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Published 10 Jun 2022

A study of the photochemical behavior of terarylenes containing allomaltol and pyrazole fragments

  • Constantine V. Milyutin,
  • Andrey N. Komogortsev,
  • Boris V. Lichitsky and
  • Valeriya G. Melekhina

Beilstein J. Org. Chem. 2022, 18, 588–596, doi:10.3762/bjoc.18.61

Graphical Abstract
  • Discussion The starting pyrazoles 12 containing the 3-hydroxypyran-4-one fragment were obtained by a literature method [33]. The methoxy derivative 16 was synthesized by methylation of the corresponding pyrazole 12a according to the standard procedure [24][26] (Scheme 2). Initially, based on the previously
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Published 27 May 2022

BINOL as a chiral element in mechanically interlocked molecules

  • Matthias Krajnc and
  • Jochen Niemeyer

Beilstein J. Org. Chem. 2022, 18, 508–523, doi:10.3762/bjoc.18.53

Graphical Abstract
  • ]. Macrocycle (S)-61, featuring two iodotriazole units, was reacted with bis-iodoalkyne 62 and azides 63a/b in order to establish the mechanical bond in an active metal template approach (using the conformational flexibility of the iodotriazole groups for copper N-ligation). Subsequent N-methylation of the
  • the thread (see Figure 16). The stereoselective binding of chiral anions by rotaxanes 64a/b was studied by 1H NMR titration experiments, using the dicationic macrocycle (S)-61-Me22+ (obtained by methylation of the triazole units in (S)-61) as a reference system. As guest molecules, the Boc-protected
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Published 06 May 2022

Menadione: a platform and a target to valuable compounds synthesis

  • Acácio S. de Souza,
  • Ruan Carlos B. Ribeiro,
  • Dora C. S. Costa,
  • Fernanda P. Pauli,
  • David R. Pinho,
  • Matheus G. de Moraes,
  • Fernando de C. da Silva,
  • Luana da S. M. Forezi and
  • Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 381–419, doi:10.3762/bjoc.18.43

Graphical Abstract
  • -methyl-1,4-dimethoxynaphthalene, the construction of the naphthoquinone ring, the methylation of 1,4-naphthoquinone, and the electrochemical synthesis from 2-methyl-1,4-dihydroxynaphthalene. The works discussed in this section are grouped according to the synthetic approach that was employed to prepare
  • dichloromethane and tert-butyl hydroperoxide at 80 °C (Table 2, entry 12). Methylation of 1,4-naphthoquinone Another route to prepare menadione (10) involves the methylation of 1,4-naphthoquinone. Because of their electron-deficient character, quinones are highly reactive with nucleophilic radicals [75]. The most
  • -workers synthetized 10 using a much simpler way (Scheme 1) [80]. These authors reported the methylation and alkylation of 1,4-naphthoquinone (1) in the presence of (NH4)2S2O8 and AgNO3 as catalyst to obtain 10 in 60% yield. Recently, Onuki and co-workers conducted dimerization reactions of 10, exploring
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Published 11 Apr 2022

Amamistatins isolated from Nocardia altamirensis

  • Till Steinmetz,
  • Wolf Hiller and
  • Markus Nett

Beilstein J. Org. Chem. 2022, 18, 360–367, doi:10.3762/bjoc.18.40

Graphical Abstract
  • -type siderophores. Structurally, compounds 1–5 are closely related to formobactin [10], brasilibactin [23], nocardimicin [24], and terpenibactins [15]. While the core scaffold of these natural products is conserved, they differ in the length of their fatty acid residues, their methylation pattern, and
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Published 30 Mar 2022

Bifunctional thiourea-catalyzed asymmetric [3 + 2] annulation reactions of 2-isothiocyanato-1-indanones with barbiturate-based olefins

  • Jiang-Song Zhai and
  • Da-Ming Du

Beilstein J. Org. Chem. 2022, 18, 25–36, doi:10.3762/bjoc.18.3

Graphical Abstract
  • oxidized to compound 4 with m-chloroperbenzoic acid under mild conditions, and compound 4 can basically maintain the original excellent stereoselectivity (Scheme 5a). Meanwhile, we are pleased that methylation of 3ah took place easily to afford product 5 in 95% chemical yield with 99% ee and >20:1 dr under
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Published 04 Jan 2022

Efficient N-arylation of 4-chloroquinazolines en route to novel 4-anilinoquinazolines as potential anticancer agents

  • Rodolfo H. V. Nishimura,
  • Thiago dos Santos,
  • Valter E. Murie,
  • Luciana C. Furtado,
  • Leticia V. Costa-Lotufo and
  • Giuliano C. Clososki

Beilstein J. Org. Chem. 2021, 17, 2968–2975, doi:10.3762/bjoc.17.206

Graphical Abstract
  • N-methylation [15]. The microwave-mediated reaction of 4-chloro-6-halo-2-phenylquinazolines 8a or 8b with o-toluidine (14a) in THF/H2O could be accomplished within 2 h and afforded the corresponding quinazoline derivatives 15a and 15b in 74% and 78% isolated yields, respectively. In addition, when
  • and 8b. Conditions: a) NBS, CH3CN, 30 min, 25 °C; b) H2O, H2O2, I2, 24 h, 50 °C. N-Arylation reactions using ortho-, meta-, and para-substituted primary anilines of type 14 followed by methylation of ortho-derivatives 15a–d, to obtain the desired 4-anilinoquinazolines of type 10. N-Arylation reactions
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Published 22 Dec 2021

α-Ketol and α-iminol rearrangements in synthetic organic and biosynthetic reactions

  • Scott Benz and
  • Andrew S. Murkin

Beilstein J. Org. Chem. 2021, 17, 2570–2584, doi:10.3762/bjoc.17.172

Graphical Abstract
  • subsequent ring-contracting α-ketol rearrangement would form 89. From here, a series of oxidation, cyclization, methylation, and/or reduction steps yield 92 and 93 (each representing two isolated products, one with R = Me and the other with R = Et). Oxidation at C1 and α-ketol rearrangement to 91, on the
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Published 15 Oct 2021

Synthesis of O6-alkylated preQ1 derivatives

  • Laurin Flemmich,
  • Sarah Moreno and
  • Ronald Micura

Beilstein J. Org. Chem. 2021, 17, 2295–2301, doi:10.3762/bjoc.17.147

Graphical Abstract
  • cofactor for methyl group transfer resulting in cytosine methylation. This recently discovered riboswitch-ribozyme activity opens new avenues for the development of RNA labeling tools based on tailored O6-alkylated preQ1 derivatives. Here, we report a robust synthesis for this class of pyrrolo[2,3-d
  • scaffold. Keywords: deazapurines; heterocycles; pyrrolopyrimidines; queuosine; RNA cofactors; RNA methylation; Introduction Methylated preQ1 has attracted much attention recently because this compound has been found to function as cofactor for the conserved fold of a non-coding RNA, namely the preQ1
  • class-I riboswitch [1]. This riboswitch acts as a ribozyme by using 7-aminomethyl-O6-methyl-7-deazaguanine (m6preQ1) as methyl group donor; it catalyzes self-methylation of a specific cytidine in the aptamer binding pocket, yielding N3-methyl cytidine (m3C) under release of 7-aminomethyl-7-deazaguanine
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Published 02 Sep 2021

Photoredox catalysis in nickel-catalyzed C–H functionalization

  • Lusina Mantry,
  • Rajaram Maayuri,
  • Vikash Kumar and
  • Parthasarathy Gandeepan

Beilstein J. Org. Chem. 2021, 17, 2209–2259, doi:10.3762/bjoc.17.143

Graphical Abstract
  • methylation of C–H bonds because it would provide a convenient access to structures that might not otherwise be available for biological testing [89][90][91]. Hence, Doyle and co-workers realized an elegant approach for the methylation of (hetero)aryl chlorides 8 using trimethyl orthoformate as a methyl
  • cycle involving the generation of methyl radicals via β-scission of a tertiary radical which in turn was generated from trimethyl orthoformate by a photogenerated chlorine radical-mediated HAT process (Figure 14) [92]. Recently, Stahl devised a photoredox nickel-catalyzed methylation of benzylic and α
  • . Proposed catalytic cycle for the nickel/photoredox-catalyzed methylation of (hetero)aryl chlorides using trimethyl orthoformate. Proposed mechanism for the photoredox nickel-catalyzed hydroalkylation of internal alkynes. Proposed mechanism for the photoredox nickel-catalyzed acylation of α-amino C(sp3)–H
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Published 31 Aug 2021

Progress and challenges in the synthesis of sequence controlled polysaccharides

  • Giulio Fittolani,
  • Theodore Tyrikos-Ergas,
  • Denisa Vargová,
  • Manishkumar A. Chaube and
  • Martina Delbianco

Beilstein J. Org. Chem. 2021, 17, 1981–2025, doi:10.3762/bjoc.17.129

Graphical Abstract
  • compounds with the same degree but different pattern of substitution, underscoring the importance of pure and well-defined polysaccharides for proper structure–property characterization. For example, compounds with an alternated methylation pattern resulted in quasi-linear structures, whereas more bent
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Published 05 Aug 2021

On the application of 3d metals for C–H activation toward bioactive compounds: The key step for the synthesis of silver bullets

  • Renato L. Carvalho,
  • Amanda S. de Miranda,
  • Mateus P. Nunes,
  • Roberto S. Gomes,
  • Guilherme A. M. Jardim and
  • Eufrânio N. da Silva Júnior

Beilstein J. Org. Chem. 2021, 17, 1849–1938, doi:10.3762/bjoc.17.126

Graphical Abstract
  • , and the introduction of methyl groups has an attractive effect on the properties of medicinal compounds [135]. However, the selective late-stage methylation has a limited scope due to the lack of suitable methodologies [136]. The insertion of methyl groups at positions adjacent to heteroatoms often
  • has a further effect improvement, however, it is even more challenging. In front of this, White and co-workers (2020) adopted a strategy consisting of an initial hydroxylation of the C(sp3)–H bonds adjacent to N- or O-heteroatoms followed by a methylation step (Scheme 19B and C) [137]. The
  • ′-bipyrrolidine) controls the site- and chemoselectivity in the hydroxylating step of the methylene C(sp3)–H bond while milder oxidation conditions help to increase the chemoselectivity. The methylation step is accomplished using a modestly nucleophilic organoaluminium reagent (AlMe3) to activate the hemiaminal
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Published 30 Jul 2021

Natural products in the predatory defence of the filamentous fungal pathogen Aspergillus fumigatus

  • Jana M. Boysen,
  • Nauman Saeed and
  • Falk Hillmann

Beilstein J. Org. Chem. 2021, 17, 1814–1827, doi:10.3762/bjoc.17.124

Graphical Abstract
  • the GT concentration at sub-lethal levels via redox cycling and S-methylation of active disulfides in GT, respectively [117][118]. Furthermore, in terms of exogenous factors, not only GT itself but several other biotic and abiotic factors, including neutrophilic granulocytes, media composition, pH
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Published 28 Jul 2021

Sustainable manganese catalysis for late-stage C–H functionalization of bioactive structural motifs

  • Jongwoo Son

Beilstein J. Org. Chem. 2021, 17, 1733–1751, doi:10.3762/bjoc.17.122

Graphical Abstract
  • electron-rich benzylic position, rationalizing the involvement of electrophilic metallonitrene intermediate 18A. Manganese-catalyzed late-stage C–H methylation The incorporation of methyl groups has the potential to manipulate absorption, distribution, metabolism, and excretion (ADME), solubility, and
  • protein–ligand binding properties as well as biological activities of small molecules, potentially leading to dramatic increases in potency, and thus has been widely explored in drug discovery [54][55][56]. Late-stage C–H methylation has recently been investigated using iron and cobalt catalysts as
  • sustainable 3d metal catalysts [57][58], while manganese-catalyzed C–H methylations are scarce [59][60]. This disparity is due to the challenges in functional group tolerance of Mn-mediated late-stage transformations. The White group reported a late-stage Mn-catalyzed C–H methylation protocol that utilizes an
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Published 26 Jul 2021

A systems-based framework to computationally describe putative transcription factors and signaling pathways regulating glycan biosynthesis

  • Theodore Groth,
  • Rudiyanto Gunawan and
  • Sriram Neelamegham

Beilstein J. Org. Chem. 2021, 17, 1712–1724, doi:10.3762/bjoc.17.119

Graphical Abstract
  • acetylation, methylation, and phosphorylation, which alter TF access; and iii) methylation of CpG islands in promoter regions that inhibit gene expression [4][5]. There are currently several isolated studies of TF–glycogene interactions, but a systematic “systems-level analysis” is absent. Many of these
  • selecting 1 million TF–gene pairs. Linear regression and statistical analysis are then performed on the top 5% hits (positive and negative coefficients) to establish TF–gene correlations. This analysis accounts for target gene copy number, tumor purity, and promoter methylation extent; and iii) TF–gene
  • glycosylation flux in cancer. Some TFs were found to interact with methyl CpG-binding TFs when regulating glycosaminoglycan proteins, implicating methylation as a possible modulator of glycosylation in cancer. Our TF–glycogene relationships, mined from Cistrome Cancer DB, represent a starting point for
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Published 22 Jul 2021

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

  • Guido Gambacorta,
  • James S. Sharley and
  • Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

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Published 18 May 2021

N-tert-Butanesulfinyl imines in the asymmetric synthesis of nitrogen-containing heterocycles

  • Joseane A. Mendes,
  • Paulo R. R. Costa,
  • Miguel Yus,
  • Francisco Foubelo and
  • Camilla D. Buarque

Beilstein J. Org. Chem. 2021, 17, 1096–1140, doi:10.3762/bjoc.17.86

Graphical Abstract
  • N-methylation led to (−)-angustureine (107) in high overall yield (Scheme 31). The same methodology was applied to the synthesis of (−)-cuspareine (108), starting in this case from enantiomeric imine (RS)-104b, and using 2-(3,4-dimethoxyphenyl)ethylmagnesium bromide as Grignard reagent. A
  • , which after desulfination and N-methylation led to expected (+)-sedamine (125) in 30% overall yield from ketone derivative 124. The stereoselective synthesis of trans-5-hydroxy-6-substituted-2-piperidinones was also reported by the group of Wei, taking advantage of the addition of Grignard reagents to N
  • -sulfinyl imine 160. A subsequent base promoted cyclization of chloroamides (158 and 162) and the products 165 and 163 were obtained in 91% and 93% yields respectively. The N-methylation of alkaloids 163 and 165 using 37% formaldehyde and sodium borohydride formed the tetrahydroisoquinoline 164 and 166 in
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Published 12 May 2021

Synthesis of 10-O-aryl-substituted berberine derivatives by Chan–Evans–Lam coupling and investigation of their DNA-binding properties

  • Peter Jonas Wickhorst,
  • Mathilda Blachnik,
  • Denisa Lagumdzija and
  • Heiko Ihmels

Beilstein J. Org. Chem. 2021, 17, 991–1000, doi:10.3762/bjoc.17.81

Graphical Abstract
  • berberrubine and berberine derivatives were synthesized by the Cu2+-catalyzed Chan–Evans–Lam coupling of berberrubine with arylboronic acids and subsequent 9-O-methylation. The reaction is likely introduced by the Cu2+-induced demethylation of berberrubine and subsequent arylation of the resulting 10-oxyanion
  • conditions to give the corresponding 9-methoxy-substituted derivatives 5a–e in moderate to good yields of 40–77% (Scheme 1). During the methylation of derivative 5f a transesterification occurred and a 2:1 mixture of the ethyl and methyl ester was formed that could not be further separated. The novel
  • methylation. The straightforward synthetic route enables the synthesis of a new class of berberine derivatives from easily accessible starting materials. The derivatives bind with slightly higher affinity to G4-DNA as compared to the parent berberine (1a) and induce a moderate stabilization of telomeric
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Published 04 May 2021

Beyond ribose and phosphate: Selected nucleic acid modifications for structure–function investigations and therapeutic applications

  • Christopher Liczner,
  • Kieran Duke,
  • Gabrielle Juneau,
  • Martin Egli and
  • Christopher J. Wilds

Beilstein J. Org. Chem. 2021, 17, 908–931, doi:10.3762/bjoc.17.76

Graphical Abstract
  • backbone modification occurs in ribosomal RNA (rRNA) of both pro- and eukaryotes [6]. A very common natural modification that concerns the ribose moiety is 2'-O-methylation (2'-OMe). 2'-OMe nucleotides are scattered throughout all types of RNA, including mRNA, tRNA, rRNA, snRNA, snoRNA, miRNA and viral RNA
  • ) (TIPDS) protected uridine, protection of N3 was needed in order to prevent methylation at this position (Scheme 4). The N3-benzoylated derivative could then be treated with methyl iodide in the presence of silver oxide in order to methylate the 2'-OH. A similar strategy was employed to synthesize 3',5'-O
  • -TIPDS-N4-benzoyl-2'-O-methylcytidine. Next, 3',5'-O-TIPDS-N6-benzoyladenosine suffered from methylation at the nucleobase and thus, 6-chloro-9-β-ᴅ-ribofuranosylpurine was instead used as the starting material. Once TIPDS protected, the 2'-OH could, once again, be selectively methylated with methyl
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Published 28 Apr 2021

Breakdown of 3-(allylsulfonio)propanoates in bacteria from the Roseobacter group yields garlic oil constituents

  • Anuj Kumar Chhalodia and
  • Jeroen S. Dickschat

Beilstein J. Org. Chem. 2021, 17, 569–580, doi:10.3762/bjoc.17.51

Graphical Abstract
  • -(allyldisulfanyl)propanoate (26) were observed. While the presence of 24 can be explained by the O-methylation of the DmdA product 37 with S-adenosylmethionine (SAM, Scheme 4E), compounds 25 and 26 require a second deallylation of 37 to 3-mercaptopropanoic acid (38) possibly by DmdA, the reaction with a
  • corresponding thiol MeSH or 13, and O-methylation (Scheme 4F). Very similar patterns of volatiles were obtained in the feeding experiments of DAllSP with D. shibae and O. indolifex (Figure 2B,C, Table 1 and Figures S2 and S3 in Supporting Information File 1). An additionally observed compound in one analysis of
  • ). While compound 23 can arise from AllMSP by deallylation to 3-(methylsulfanyl)propanoic acid (36), potentially through DmdA, and O-methylation, the derivative 24 may be formed analogously through intermediate 37 (Scheme 4A and E). The higher production of 23 in comparison to 24 suggests that the
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Published 26 Feb 2021

Benzothiazolium salts as reagents for the deoxygenative perfluoroalkylthiolation of alcohols

  • Armin Ariamajd,
  • Nils J. Gerwien,
  • Benjamin Schwabe,
  • Stefan Dix and
  • Matthew N. Hopkinson

Beilstein J. Org. Chem. 2021, 17, 83–88, doi:10.3762/bjoc.17.8

Graphical Abstract
  • observed within 16 h at rt, and the heteroaromatic compounds 1a–e could be isolated in good yields. Subsequent N-methylation with methyl trifluoromethanesulfonate in CH2Cl2 also proceeded smoothly with the BT-SRF reagents each being obtained after 48 h at rt in high yields upon precipitation with Et2O. As
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Published 08 Jan 2021

Progress in the total synthesis of inthomycins

  • Bidyut Kumar Senapati

Beilstein J. Org. Chem. 2021, 17, 58–82, doi:10.3762/bjoc.17.7

Graphical Abstract
  • inthomycins [36]. These triene moieties are a sub-unit of the oxazolomycin class of antibiotics. To prepare the phenyl analogue of racemic inthomycin C (rac-3), at first, the phosphonate 28 was prepared using a Claisen condensation of ethyl propionate (25) followed by methylation of 26a, treatment with
  • benzoate to give (−)-141 in good yield. Next, the benzoate-protected ynoate (−)-141 was converted into aldehyde (Z)-(+)-143a by employing a copper-catalyzed methylation of the alkyne moiety to the corresponding enoate (Z)-(+)-142 followed by an ester reduction–oxidation sequence using DIBAL-H and TPAP
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Published 07 Jan 2021

All-carbon [3 + 2] cycloaddition in natural product synthesis

  • Zhuo Wang and
  • Junyang Liu

Beilstein J. Org. Chem. 2020, 16, 3015–3031, doi:10.3762/bjoc.16.251

Graphical Abstract
  • -catalyzed intermolecular carboxylatve TMM [3 + 2] cycloaddition [36] of enone 65 and TMM donor 62 to forge the highly-substituted spirocyclic cyclopentane 66a [38] (Scheme 4A). Methylation of the resultant cyclopentane 66a gave methyl ester 66b in 93% yield over two steps. A six-step synthesis from ester
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Published 09 Dec 2020

Anion exchange resins in phosphate form as versatile carriers for the reactions catalyzed by nucleoside phosphorylases

  • Julia N. Artsemyeva,
  • Ekaterina A. Remeeva,
  • Tatiana N. Buravskaya,
  • Irina D. Konstantinova,
  • Roman S. Esipov,
  • Anatoly I. Miroshnikov,
  • Natalia M. Litvinko and
  • Igor A. Mikhailopulo

Beilstein J. Org. Chem. 2020, 16, 2607–2622, doi:10.3762/bjoc.16.212

Graphical Abstract
  • phosphate [28][29]) and moderate or low yields, on the one hand, and the need to obtain N7Me-Gua [30][32][33][34][35] and N7Me-dGua [31][34][36][37][38] by chemical methylation, the failure of Ara-1P synthesis [34], and the need to utilize N7-methylguanine, on the other. In a recently published work by
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Published 22 Oct 2020

NMR Spectroscopy of supramolecular chemistry on protein surfaces

  • Peter Bayer,
  • Anja Matena and
  • Christine Beuck

Beilstein J. Org. Chem. 2020, 16, 2505–2522, doi:10.3762/bjoc.16.203

Graphical Abstract
  • shifts for both 1H and 13C nuclei. Methylation of Lys and Arg occurs as posttranslational modification (PTM) of proteins in nature, often used as a switch to regulate protein interactions and thus their function [112][113]. The Crowley lab has used this advantage to study the binding of sulfonatocalix[4
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Published 09 Oct 2020
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