Silyl-protective groups influencing the reactivity and selectivity in glycosylations

• Mikael Bols and
• Christian Marcus Pedersen

Beilstein J. Org. Chem. 2017, 13, 93–105, doi:10.3762/bjoc.13.12

• glycosylation with a TES-protected glycosyl donor has also been performed in a case where the target contained a 6-O-acylglucoside and hence protective groups that could be removed under mild acidic conditions were needed [9]. This was for example used for the synthesis of the serine protease inhibitor

Phosphated cyclodextrins as water-soluble chiral NMR solvating agents for cationic compounds

• Cira Mollings Puentes and
• Thomas J. Wenzel

Beilstein J. Org. Chem. 2017, 13, 43–53, doi:10.3762/bjoc.13.6

• )cyclohexanemethanol (13), alanine methyl ester (14), 2-phenylglycine methyl ester (15), phenylalanine methyl ester (16), tyrosine (17), 4-chlorophenylalanine methyl ester (18), 4-chlorophenylalanine ethyl ester (19), carbobenzyloxy serine (20), 2-methylindoline (21), trans-1-amino-2-indanol (22), cis-1-amino-2

First DMAP-mediated direct conversion of Morita–Baylis–Hillman alcohols into γ-ketoallylphosphonates: Synthesis of γ-aminoallylphosphonates

• Marwa Ayadi,
• Haitham Elleuch,
• Emmanuel Vrancken and
• Farhat Rezgui

Beilstein J. Org. Chem. 2016, 12, 2906–2915, doi:10.3762/bjoc.12.290

• have been exploited as valuable building blocks in natural product syntheses, e.g., calyculins A and B as potent serine-threonine protein phosphatase inhibitors [6], as well as ligands in enantioselective reactions [7]. Furthermore, allylphosphonates are important bioactive compounds that exhibit

Biochemical and structural characterisation of the second oxidative crosslinking step during the biosynthesis of the glycopeptide antibiotic A47934

• Veronika Ulrich,
• Clara Brieke and
• Max J. Cryle

Beilstein J. Org. Chem. 2016, 12, 2849–2864, doi:10.3762/bjoc.12.284

• serine residue of the PCP-domain using the R4-4 mutant of the promiscuous phosphopantetheinyl transferase Sfp. The substrate peptide is attached to the PCP-domain via a coenzyme A-derived phosphopantetheine moiety. Excess of substrate is removed via centrifugation using centrifugal filter units with an

Inhibition of peptide aggregation by means of enzymatic phosphorylation

• Kristin Folmert,
• Malgorzata Broncel,
• Hans v. Berlepsch,
• Christopher H. Ullrich,
• Mary-Ann Siegert and
• Beate Koksch

Beilstein J. Org. Chem. 2016, 12, 2462–2470, doi:10.3762/bjoc.12.240

• group. We explored a 26-residue coiled-coil peptide which undergoes a conformational transition to amyloid fibrils in 24 hours under physiological conditions [41], but remains random coil if one of three serine residues carries a phosphate group [27]. The aggregation process could be restored by

• between glutamates and lysines. Intermolecular coulombic interactions between e and g direct the monomers into a parallel dimeric orientation. The solvent-exposed position f is occupied by serine for better solubility. One site of each position b, c, and f contains valine, making the system prone to

• cells [50]. The serine/threonine kinase PKA uses ATP as phosphate donor. It has to be activated from its natural species with cAMP which leads to dissociation of PKA in two regular and two catalytic subunits [51]. We used the preactivated catalytic subunit of PKA to perform the reactions. The structural

Enduracididine, a rare amino acid component of peptide antibiotics: Natural products and synthesis

• Darcy J. Atkinson,
• Briar J. Naysmith,
• Daniel P. Furkert and
• Margaret A. Brimble

Beilstein J. Org. Chem. 2016, 12, 2325–2342, doi:10.3762/bjoc.12.226

• synthetically broken down into tripeptides 78 and 79 (Scheme 15). Tripeptide 78 was further disconnected into protected serine 80 and protected β-hydroxyenduracididine residues 81 and 82. The synthesis of key amino acids 81 and 82 was based on an aldol reaction between protected aldehyde 83 and glycine 84

p-Nitrophenyl carbonate promoted ring-opening reactions of DBU and DBN affording lactam carbamates

• Madhuri Vangala and
• Ganesh P Shinde

Beilstein J. Org. Chem. 2016, 12, 2086–2092, doi:10.3762/bjoc.12.197

• containing substrates such as the p-nitrophenyl carbonate of 9-fluorenemethanol 16a and N-Cbz-L-serine methyl ester 17a, resulted in the dibenzofulvene product 16b in the former, and a mixture of products in the latter, with DBN acting as a base. Even though the γ-lactam products were the only major

Synthesis of the C8’-epimeric thymine pyranosyl amino acid core of amipurimycin

• Pramod R. Markad,
• Navanath Kumbhar and
• Dilip D. Dhavale

Beilstein J. Org. Chem. 2016, 12, 1765–1771, doi:10.3762/bjoc.12.165

• D-serine as a starting material [6]. In this regard, our group has recently reported the synthesis of the C3’-branched carbohydrate core of amipurimycin starting from D-glucose [15]. In the continuation of this area, we now report the synthesis of the amipurimycin pyranose core comprising of (a) a

TMSBr-mediated solvent- and work-up-free synthesis of α-2-deoxyglycosides from glycals

• Mei-Yuan Hsu,
• Yi-Pei Liu,
• Sarah Lam,
• Su-Ching Lin and
• Cheng-Chung Wang

Beilstein J. Org. Chem. 2016, 12, 1758–1764, doi:10.3762/bjoc.12.164

• -butanol (16), 5-azidopentanol (17), cyclohexanol (18) and 2-adamantanol (19), to give O-2-deoxyglucosides in high yields (74–90%) and α-selectivities (α:β = 7–10:1, Table 3, entries 2–8). Regarding the glycosylation with amino acid derivatives, L-serine 20 and threonine derivative 21, increased ratio of β

• -Serine and threonine derivatives 20 and 21 reacted with galactal 4 to give the glycosylated amino acids 59 and 60 (Table 4, entries 9 and 10) in excellent selectivities (59, α only; 60, α:β = 9:1) but in different yields (59, 50%; 60, 97%). In Table 4, entry 11, disaccharide 61 was acquired in the

Biosynthesis of oxygen and nitrogen-containing heterocycles in polyketides

• Franziska Hemmerling and
• Frank Hahn

Beilstein J. Org. Chem. 2016, 12, 1512–1550, doi:10.3762/bjoc.12.148

Cyclisation mechanisms in the biosynthesis of ribosomally synthesised and post-translationally modified peptides

• Andrew W. Truman

Beilstein J. Org. Chem. 2016, 12, 1250–1268, doi:10.3762/bjoc.12.120

• -translationally modified into the final product, and a heterotrimeric complex that is responsible for both heterocyclisation of serine and cysteine residues, and subsequent oxidation of (ox/thi)azolines into (ox/thi)azoles (Figure 3A). This catalytic complex consists of “C” and “D” proteins (annotated as McbB and

• McbD, respectively, for microcin B17) that cooperate to catalyse heterocyclisation of specific serine and cysteine residues in McbA, and a flavin-dependent dehydrogenase (the “B-protein”, McbC for microcin B17) that oxidises these heterocycles. These early in vitro studies indicated that the “C-protein

• then be attacked by an adjacent serine or cysteine side chain, thus releasing phosphate/AMP and generating the heterocycle. This order of steps was not advocated by either the Naismith or Mitchell groups as it requires a disfavoured 5-endo-trig cyclisation, although this mode of cyclisation is

NeoPHOX – a structurally tunable ligand system for asymmetric catalysis

• Jaroslav Padevět,
• Marcus G. Schrems,
• Robin Scheil and
• Andreas Pfaltz

Beilstein J. Org. Chem. 2016, 12, 1185–1195, doi:10.3762/bjoc.12.114

• Jaroslav Padevet Marcus G. Schrems Robin Scheil Andreas Pfaltz Department of Chemistry, University of Basel, St. Johanns-Ring 19, CH-4056 Basel, Switzerland 10.3762/bjoc.12.114 Abstract A synthesis of new NeoPHOX ligands derived from serine or threonine has been developed. The central

• the substantially higher ee values induced by the analogous catalyst Ir-1a [28] lacking substituents at C(5). Based on these negative results we chose a new approach based on serine or threonine as starting materials (Figure 4). The carboxyl group of these amino acids serves as surrogate for the tert

• protecting group, the steric properties of the ligand can be optimized for a specific application. PHOX ligands of this type have been previously prepared from serine and successfully used in iridium-catalyzed hydrogenation [29][30]. Synthesis of serine- and threonine-derived NeoPHOX ligands The synthesis

One-pot synthesis of enantiomerically pure N-protected allylic amines from N-protected α-amino esters

• Gastón Silveira-Dorta,
• Sergio J. Álvarez-Méndez,
• Víctor S. Martín and
• José M. Padrón

Beilstein J. Org. Chem. 2016, 12, 957–962, doi:10.3762/bjoc.12.94

• better Z-(dia)stereoselectivity was observed when compared to the previous one-pot method. The (dia)stereoselectivity of the process was affected neither by the reaction solvent nor by the amount of DIBAL-H employed. The method is compatible with the presence of free hydroxy groups as shown with serine

• -protected α-amino esters requires three chemical steps, i.e. reduction, oxidation and olefination (Figure 1) [9][10]. When the benzyl group is used as protecting group for the nitrogen functionality, the method represents a variation of the well-known Reetz protocol [11]. In the particular case of serine

• aldehydes. It comprises the one-pot sequential reduction to aldehyde with DIBAL-H at −78 °C and subsequent in situ addition of Grignard reagents. Remarkably, our method is friendly with serine and threonine derivatives without the requisite to protect the β-hydroxy group. With this tool in hand, we thought

Muraymycin nucleoside-peptide antibiotics: uridine-derived natural products as lead structures for the development of novel antibacterial agents

• Daniel Wiegmann,
• Stefan Koppermann,
• Marius Wirth,
• Giuliana Niro,
• Kristin Leyerer and
• Christian Ducho

Beilstein J. Org. Chem. 2016, 12, 769–795, doi:10.3762/bjoc.12.77

• . synthesised the hydroxyleucine moiety found in naturally occurring muraymycins of classes A to C (Scheme 8) [107]. Adapting a strategy developed by Zhu et al., D-serine (59) was stereoselectively converted into the protected amino alcohol 60 [108]. Key intermediate 60 was then Cbz- and acetonide protected to

Gold-catalyzed direct alkynylation of tryptophan in peptides using TIPS-EBX

• Gergely L. Tolnai,
• Jonathan P. Brand and
• Jerome Waser

Beilstein J. Org. Chem. 2016, 12, 745–749, doi:10.3762/bjoc.12.74

• under mild conditions and could be applied to peptides containing other nucleophilic and aromatic amino acids, such as serine, phenylalanine or tyrosine. Keywords: alkynes; C–H functionalization; gold catalysis; hypervalent iodine; peptides; Introduction Alkynes have always been important building

• other aromatic amino acids, such as phenylalanine or tyrosine (products 5c and 5d). Serine and proline containing dipeptides 5e and 5f could also be obtained in 64% and 53% yield, respectively. The reaction was therefore general for dipeptides bearing tryptophan at the C-terminus. On the other hand

Unconventional application of the Mitsunobu reaction: Selective flavonolignan dehydration yielding hydnocarpins

• Guozheng Huang,
• Simon Schramm,
• Jörg Heilmann,
• David Biedermann,
• Vladimír Křen and
• Michael Decker

Beilstein J. Org. Chem. 2016, 12, 662–669, doi:10.3762/bjoc.12.66

• alcohols and bulky acids: Cherney and Wang observed an elimination of a serine derivative during esterification experiments [23]. During conversion of substituted benzyl alcohols to amines under Mitsunobu conditions, elimination also occurred [24]. Dehydration under Mitsunobu conditions has been applied in

Antibiotics from predatory bacteria

• Juliane Korp,
• María S. Vela Gurovic and
• Markus Nett

Beilstein J. Org. Chem. 2016, 12, 594–607, doi:10.3762/bjoc.12.58

• , requires a tight regulatory network in predatory myxobacteria [80]. This is also reflected in the genome of M. xanthus DK1622, which features an unusual high duplication frequency of genes encoding regulatory proteins like serine-threonine kinases and enhancer binding proteins (EBPs) [43]. EBPs are

Natural products from microbes associated with insects

• Christine Beemelmanns,
• Huijuan Guo,
• Maja Rischer and
• Michael Poulsen

Beilstein J. Org. Chem. 2016, 12, 314–327, doi:10.3762/bjoc.12.34

• D-serine. Due to the presence in conidia, serinocyclines have also been hypothesized to play a role in the virulence of M. anisopliae. Chemical analysis of the entomopathogenic fungus B. bassiana yielded beauvericin (43), a depsipeptide with alternating methylphenylalanyl and hydroxyisovaleryl

Pyridinoacridine alkaloids of marine origin: NMR and MS spectral data, synthesis, biosynthesis and biological activity

• Louis P. Sandjo,
• Victor Kuete and
• Maique W. Biavatti

Beilstein J. Org. Chem. 2015, 11, 1667–1699, doi:10.3762/bjoc.11.183

• phosphatase B (PtpB) [31] and serine protease [32]. The focus of this review is on pyridoacridine-related metabolites as one of the many interesting groups of alkaloids produced from marine sources. They are generally produced by marine sponges, ascidians [33] and tunicates [34] and they are structurally

Orthogonal dual-modification of proteins for the engineering of multivalent protein scaffolds

• Michaela Mühlberg,
• Michael G. Hoesl,
• Christian Kuehne,
• Jens Dernedde,
• Nediljko Budisa and
• Christian P. R. Hackenberger

Beilstein J. Org. Chem. 2015, 11, 784–791, doi:10.3762/bjoc.11.88

• amino acids like glycine, alanine or serine in the native process of N-terminal methionine excision (NME) [43]. This process exposes Ser2 at the N-terminus for subsequent N-terminal oxime ligation. It has to be noted that the incorporation of Aha, as known [42][44], can hamper NME and therefore delivers

Regulation of integrin and growth factor signaling in biomaterials for osteodifferentiation

• Qiang Wei,
• Theresa L. M. Pohl,
• Anja Seckinger,
• Joachim P. Spatz and
• Elisabetta A. Cavalcanti-Adam

Beilstein J. Org. Chem. 2015, 11, 773–783, doi:10.3762/bjoc.11.87

• higher bioactivity compared to their corresponding homodimers [57]. BMP receptors (BMPRs) belong to the group of serine/threonine kinase transmembrane receptors and are subdivided into type I and II receptors [64][65]. There are three type I receptors, namely BMPR-IA (also known as ALK-3, activin

Chemoselective O-acylation of hydroxyamino acids and amino alcohols under acidic reaction conditions: History, scope and applications

• Tor E. Kristensen

Beilstein J. Org. Chem. 2015, 11, 446–468, doi:10.3762/bjoc.11.51

• derivatives of many amino acids often become annoyingly strenuous due to the necessity of employing protecting groups, on one or more of the amino acid functionalities, during the synthetic sequence. However, in the case of hydroxyamino acids such as hydroxyproline, serine, threonine, tyrosine and 3,4

• ; organocatalysis; serine; threonine; tyrosine; Introduction Any adept researcher within the field of organic synthetic chemistry will be mindful of the outstanding importance of amino acids as inexpensive chiral starting materials in the synthesis of a nearly infinite variety of synthetic end products. This

• the copper salt with hydrogen sulfide. This methodology has subsequently been employed in a more generic sense as a preparative method for synthesis of acrylic side-chain derivatives of amino acids such as lysine, ornithine, tyrosine and serine [6][7][8], having modified the original technique by

Versatile synthesis of amino acid functionalized nucleosides via a domino carboxamidation reaction

• Vicky Gheerardijn,
• Jos Van den Begin and
• Annemieke Madder

Beilstein J. Org. Chem. 2014, 10, 2566–2572, doi:10.3762/bjoc.10.268

• functionalities on the nucleoside. As proof of principle and with the catalytic serine–histidine–aspartate catalytic triad of serine proteases in mind, we illustrate the preparation of three different nucleosides equipped with three functional amino acids containing hydroxy, imidazole, amine and carboxylate

• assembly of the desired chain without DNA damage. In the current study, we have chosen to couple three amino acids, which contain functional groups commonly used in SELEX approaches to modify DNA or RNA, to 5-iodo-2’-deoxyuridine. We describe the direct and linker-less introduction of histidine, serine and

• accomplished under standard conditions and the corresponding derivative 5 was isolated and purified without problems. As a second example we decided to employ serine as amino acid for introduction onto the nucleoside. In view of the earlier illustrated need for imidazole protection during introduction of

Towards the sequence-specific multivalent molecular recognition of cyclodextrin oligomers

• Michael Kurlemann and
• Bart Jan Ravoo

Beilstein J. Org. Chem. 2014, 10, 2428–2440, doi:10.3762/bjoc.10.253

• Supporting Information File 1). The di- and trivalent guest strands 8–14 (Figure 1C, D) were synthesized by solid phase peptide synthesis using a standard Fmoc-protocol (Figure 3). Therefore the serine derivatives 15 and 16 (Figure 1E) and a water-soluble linker molecule were used. The purity of the guest

• strands is estimated to be >95% based on 1H NMR spectra (see Supporting Information File 1). The syntheses of the multivalent host and guest strands are described in detail in Supporting Information File 1. First of all, the selectivity of the complexation of the unprotected serine derivatives 17 and 18

• towards α- and β-CD was investigated by ITC experiments. The structures of the host–guest complexes were elucidated by NMR spectroscopy. The 1-adamantane-functionalized serine 17 shows complexation of α- and β-CD, forming 1:1 complexes. In both cases the adamantane moiety binds into the CD cavity, which

Application of cyclic phosphonamide reagents in the total synthesis of natural products and biologically active molecules

• Thilo Focken and
• Stephen Hanessian

Beilstein J. Org. Chem. 2014, 10, 1848–1877, doi:10.3762/bjoc.10.195

• -workers led to a reassignment of its structure and that of the parent molecules, such as polyoxin A (69) [24][25][26]. The synthesis of the E-isomer of polyoximic acid started from protected D-serine 70, which was converted into diazoketone 71 by reacting a mixed anhydride with diazomethane (Scheme 10