Flow synthesis of a versatile fructosamine mimic and quenching studies of a fructose transport probe

• Matthew B. Plutschack,
• D. Tyler McQuade,
• Giulio Valenti and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2013, 9, 2022–2027, doi:10.3762/bjoc.9.238

• , methionine and histidine. As expected, the amino acids lacking functionality known to quench fluorophores (alanine, glutamine and lysine) did not quench NBDM at concentrations as high as 50 mM. Interestingly, tyrosine did not quench NBDM fluorescence even at concentrations as high as 2 mM (solubility limit

• for tyrosine). Methionine and histidine, however, did quench NBDM via a dynamic mechanism (Figure 4). Carbohydrate–carbohydrate and carbohydrate–aromatic ring interactions are well-known [29][30]. Based on these interactions, we hypothesized that abnormal fluorescence behavior may be exhibited at high

• fitted using a polynomial fit (order = 2) with direct weighting. Comparison of quenching 2 µM NBDM, as measured by fluorescence intensity of methionine and histidine. Each data set was plotted in OriginPro 8.6 and fitted using a linear fit with direct weighting. Batch synthesis of NBDM. a) NaNO2

Isotopically labeled sulfur compounds and synthetic selenium and tellurium analogues to study sulfur metabolism in marine bacteria

• Nelson L. Brock,
• Christian A. Citron,
• Claudia Zell,
• Martine Berger,
• Irene Wagner-Döbler,
• Jörn Petersen,
• Thorsten Brinkhoff,
• Meinhard Simon and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2013, 9, 942–950, doi:10.3762/bjoc.9.108

• further corroborated the proposed second demethylation activity in R. pomeroyi. Isotopically labeled [2H3]methionine and 34SO42−, synthesized from elemental 34S8, were tested to identify alternative sulfur sources besides DMSP for the MeSH production in P. gallaeciensis. Methionine proved to be a viable

• genome only encodes DddP as a single DMSP lyase, while no conclusions can be drawn on the participation of DddW. Exploring the source of methanethiol Two possible sources for MeSH production from MB2216 medium are sulfate via reduction to sulfide and methylation, or methionine via γ-lysis. The

• participation of both mechanisms was explored by feeding of isotopically labeled sulfate, thiosulfate and methionine. The volatiles released by agar-plate cultures of P. gallaeciensis fed with NaH34SO4 or Na34SSO3, both synthesized from elemental 34S8 (Scheme 3), were collected by using a CLSA and analyzed by

Chemical–biological characterization of a cruzain inhibitor reveals a second target and a mammalian off-target

• Jonathan W. Choy,
• Clifford Bryant,
• Claudia M. Calvet,
• Patricia S. Doyle,
• Shamila S. Gunatilleke,
• Siegfried S. F. Leung,
• Kenny K. H. Ang,
• Steven Chen,
• Jiri Gut,
• Juan A. Oses-Prieto,
• Jonathan B. Johnston,
• Michelle R. Arkin,
• Alma L. Burlingame,
• Jack Taunton,
• Matthew P. Jacobson,
• James M. McKerrow,
• Larissa M. Podust and
• Adam R. Renslo

Beilstein J. Org. Chem. 2013, 9, 15–25, doi:10.3762/bjoc.9.3

• tryptic peptide S264-R281 from mouse cathepsin B, identified in pull-down experiments employing compound 9 in C2C12 cells. Observed sequence ions are labeled (m = oxidized methionine). In vitro biochemical and cellular activities of test compounds and controls. (n.a. = not active (cruzain IC50 > 50 μM

Flow photochemistry: Old light through new windows

• Jonathan P. Knowles,
• Luke D. Elliott and
• Kevin I. Booker-Milburn

Beilstein J. Org. Chem. 2012, 8, 2025–2052, doi:10.3762/bjoc.8.229

• degradations, dual-channel reactors have been used for synthetically useful transformations. Returning to the oxidation of α-terpinene, moderate yields of ascaridole were obtained by using a silica-supported fullerene promoter [38]. Similarly, L-methionine was efficiently oxidised to the corresponding

• sulphoxide in the same reactor [38]. Again, an issue with the reactor was the low productivity: in the case of the oxidation of α-terpinene, productivities were in the order of 10 mg/h, whilst the oxidation of methionine proved less productive at 4.5 mg/h. Neither of these seems likely to be of synthetic use

Intramolecular carbenoid ylide forming reactions of 2-diazo-3-keto-4-phthalimidocarboxylic esters derived from methionine and cysteine

• Marc Enßle,
• Stefan Buck,
• Roland Werz and
• Gerhard Maas

Beilstein J. Org. Chem. 2012, 8, 433–440, doi:10.3762/bjoc.8.49

• Marc Enssle Stefan Buck Roland Werz Gerhard Maas Institute of Organic Chemistry I, University of Ulm, Albert-Einstein-Allee 11, D-89081 Ulm, Germany 10.3762/bjoc.8.49 Abstract Methionine, S-benzylcysteine and S-allylcysteine were converted into 2-diazo-3-oxo-4-phthalimidocarboxylic esters 8a–c in

• rearrangement. The short-lived carbonyl ylides derived from methionine and S-benzylcysteine formed head-to-tail dimers by a [3 + 3]-cycloaddition and could be trapped with external dipolarophiles, while the S-allyl derivative 14c yielded the pentacyclic compound 17 by an intramolecular [3 + 2]-cycloaddition

• -β-ketoesters 1, stable four- to seven-membered cyclic ylides 2 were obtained (Scheme 1); in the case of R2 = allyl, however, the ylides underwent a spontaneous [2,3]-sigmatropic rearrangement. On the other hand, the conversion of methionine-derived diazoketone 3 into the cyclic sulfonium ylide 4 was

Novel fatty acid methyl esters from the actinomycete Micromonospora aurantiaca

• Jeroen S. Dickschat,
• Hilke Bruns and
• Ramona Riclea

Beilstein J. Org. Chem. 2011, 7, 1697–1712, doi:10.3762/bjoc.7.200

• with isotopically labelled [2H10]leucine, [2H10]isoleucine, [2H8]valine, [2H5]sodium propionate, and [methyl-2H3]methionine demonstrated that the responsible fatty acid synthase (FAS) can use different branched and unbranched starter units and is able to incorporate methylmalonyl-CoA elongation units

• for internal methyl branches in various chain positions, while the methyl ester function is derived from S-adenosyl methionine (SAM). Keywords: actinomycetes; FAMEs; fatty acid biosynthesis; GC–MS; volatiles; Introduction Lipids in general, and particularly fatty acids (FAs), belong to the most

• building blocks for the biosynthesis of these methyl esters are highlighted in bold and by use of a colour code in Figure 1. For the methyl 2-methylalkanoates and -alk-2-enoates from Chitinophaga, the origin of the methyl group from S-adenosyl methionine (SAM, purple) and of the 2-methyl groups from

Natural product biosyntheses in cyanobacteria: A treasure trove of unique enzymes

• Jan-Christoph Kehr,
• Douglas Gatte Picchi and
• Elke Dittmann

Beilstein J. Org. Chem. 2011, 7, 1622–1635, doi:10.3762/bjoc.7.191

• ]. Unique features of the cluster include a putative GCN5-related transferase, which is suggested to transfer three methyl groups from S-adenosyl-methionine (SAM) to malonyl-CoA to yield the tert-butyl terminus of apratoxin. The cluster further encodes a series of proteins resembling an HCS-like gene

Ratiometric fluorescent probe for enantioselective detection of D-cysteine in aqueous solution

• Xiao-bo Zhou,
• Wing-Hong Chan,
• Albert W. M. Lee and
• Chi-Chung Yeung

Beilstein J. Org. Chem. 2011, 7, 1508–1515, doi:10.3762/bjoc.7.176

• -mercaptoamino group present in Cys. When the thiol group in Hcy is methylated, as in methionine, its power to bind to the sensor is completely lost. As none of the bifunctional α-amino acids caused any fluorescence quenching of the probe, the presence of β-mercaptoamino moiety in cysteine may confer a

A novel high-yield synthesis of aminoacyl p-nitroanilines and aminoacyl 7-amino-4-methylcoumarins: Important synthons for the synthesis of chromogenic/fluorogenic protease substrates

• Xinghua Wu,
• Yu Chen,
• Herve Aloysius and
• Longqin Hu

Beilstein J. Org. Chem. 2011, 7, 1030–1035, doi:10.3762/bjoc.7.117

• removal of the Boc protecting group and oxidation of the free amino group to the nitro group [13]. This method, however, is not applicable to methionine, tyrosine, tryptophan and cysteine, all of which are sensitive to the oxidation conditions used. As an alternative, Nα-protected amino acids were used to

Photoinduced electron-transfer chemistry of the bielectrophoric N-phthaloyl derivatives of the amino acids tyrosine, histidine and tryptophan

• Axel G. Griesbeck,
• Jörg Neudörfl and
• Alan de Kiff

Beilstein J. Org. Chem. 2011, 7, 518–524, doi:10.3762/bjoc.7.60

•  1). For example, the glutamic acid derivative 3 resulted in the formation of a diastereoisomeric mixture of benzopyrrolizidinones 4 [6]. For a specific system, N-phthaloyl methionine (5), we have detected bielectrophoric behavior in that the electron transfer from the thioether group competes

Synthesis of new C^α-tetrasubstituted α-amino acids

• Andreas A. Grauer and
• Burkhard König

Beilstein J. Org. Chem. 2009, 5, No. 5, doi:10.3762/bjoc.5.5

• structure, because of their ability to rigidify the peptide backbone. Recently our group reported a new class of cyclic Cα-tetrasubstituted tetrahydrofuran α-amino acids prepared from methionine and aromatic aldehydes. We now report the extension of this methodology to aliphatic aldehydes. Although such

• from commercially available racemic methionine in a four step synthesis. TAAs show the ability to induce stable β-turns in solid state and solution when incorporated into natural peptide sequences [20]. The key step of the TAA synthesis is the ring formation, which is an aldol type reaction between the

• sulfonium salt 1 and an aldehyde. Applying strongly basic conditions leads to the abstraction of the α-proton of the methionine, the aldehyde undergoes nucleophilic attack by the ester enolate and the displacement of the sulfonium salt substituent by the alkoxy group gives the target TAA. To avoid undesired

The first preparative solution phase synthesis of melanotan II

• Vladimir V. Ryakhovsky,
• Georgy A. Khachiyan,
• Nina F. Kosovova,
• Elena F. Isamiddinova and
• Andrey S. Ivanov

Beilstein J. Org. Chem. 2008, 4, No. 39, doi:10.3762/bjoc.4.39

• . Hruby at University of Arizona [12][13][14][15][16][17][18][19] and other research groups [20][21][22][23]. Modification of the α-MSH structure, including replacement of the oxidizable L-methionine with isosteric L-norleucine, replacement of L-phenylalanine with its enantiomer D-phenylalanine, and