DNA functionalization by dynamic chemistry

• Zeynep Kanlidere,
• Oleg Jochim,
• Marta Cal and
• Ulf Diederichsen

Beilstein J. Org. Chem. 2016, 12, 2136–2144, doi:10.3762/bjoc.12.203

• libraries of reversibly interconverting building blocks. The syntheses of phosphoramidite building blocks derived from D-threoninol are presented in two variants with protected amino or thiol groups. The threoninol building blocks were successfully incorporated via automated solid-phase synthesis into 13mer

• ][26][27][28]. Similarly, a thiol functionality can be introduced by substitution of the amine group of threoninol and incorporated into the oligonucleotide backbone. The amine and thiol groups can be used for further oligonucleotide functionalization reacting these sites with functional molecules like

• template-directed selection of one nucleobase from the reaction mixture with the amine or thiol functional group was investigated [44][45][46][47]. In our studies, dynamic chemistry is applied for post-synthetic functionalization of the threoninol based modified oligonucleotides in a reversible manner

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

• , entries 2–6). For per-O-benzylated glucal (3) and per-O-acetylated rhamnal (5), the corresponding thiol-2-deoxyglycosides 7 (61%, α:β = 2:1) and 10 (76%, α:β = 2:1) were produced in good yields with moderate stereoselectivity (Table 1, entry 2 and 5). Interestingly, as shown in Table 1, entries 1 and 2

• sequential steps (Scheme 1). Monosaccharide acceptor 64 underwent the TMSBr-mediated nucleophilic addition to glucal 1 to produce exclusively disaccharide 65 (97%, α:β = 7:1) in an excellent yield with high α-selectivity. Remarkably, the 1-thiol group remained intact after the formation of disaccharide 65

From N-vinylpyrrolidone anions to modified paraffin-like oligomers via double alkylation with 1,8-dibromooctane: access to covalent networks and oligomeric amines for dye attachment

• Daniela Obels,
• Melanie Lievenbrück and
• Helmut Ritter

Beilstein J. Org. Chem. 2016, 12, 1395–1400, doi:10.3762/bjoc.12.133

• paraffin-like oligomeric chains bearing polymerizable vinyl moieties. These oligomers were radically crosslinked in bulk with N-VP as co-monomer yielding swellable polymer disks. The vinylic side groups of the N-VP oligomers allow thiol–ene click reactions with 2-aminoethanethiol hydrochloride to obtain

• poly(ethylene glycol) side chains. Keywords: double alkylation; modified N-vinylpyrrolidone; oligomeric anthraquinone dye; paraffin-like oligomer; radical thiol-ene click reaction; Introduction Poly(N-vinylpyrrolidone) (PVP) is established in daily life due to its high water solubility and

• present the synthesis of paraffin-like oligomers via double alkylation of N-VP with 1,8-dibromooctane. Additionally, this work focuses on the use of the free double bonds for radical crosslinking as well as thiol-ene modification for subsequent dye attachment. Results and Discussion N-Vinylpyrrolidone (1

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

• oxidise the cysteine. A mechanistic proposal based on structural data involves the oxidation of the thiol to a thioaldehyde, which then functions as an electron sink to facilitate decarboxylation to generate the double bond between Cα and Cβ [66] (Figure 5A). The functional characterisation of EpiD led to

• generate a 5’-deoxyadenosyl radical (5’-dA•). The formation of 5’-dA• is common to all radical SAM proteins. The second [4Fe-4S] cluster coordinates the peptide substrate via a deprotonated thiol group of a cysteine. The 5’-dA• abstracts a hydrogen from a specific α-carbon, which then attacks the thiol

Conjugate addition–enantioselective protonation reactions

• James P. Phelan and
• Jonathan A. Ellman

Beilstein J. Org. Chem. 2016, 12, 1203–1228, doi:10.3762/bjoc.12.116

• to the enantioselective addition of aromatic thiols to 2-phthalimidoacrylates 29 in high yield and good enantioselectivity (Scheme 7) [24]. A variety of electron rich, neutral, and poor thiols coupled efficiently. Impressively, the aromatic thiol 28 could be substituted with hydroxy and amino groups

• (Scheme 23c). Following Tan’s work on the conjugate addition–enantioselective protonation of cyclic itaconimide 95, both the Singh and Chen groups investigated the addition of thiol nucleophiles to acyclic imides. Utilizing thiourea catalyst 102a, Singh and co-workers reported the catalytic

• in high yield and enantioselectivity. Only when R1 was phenyl did the enantioselectivity of the thiol addition drop below 91.5:8.5 er to 85:15 er. The addition of a variety of α-substituted malononitriles 126e also proceeded in high yield and enantioselectivity. During the exploration of different

A cross-metathesis approach to novel pantothenamide derivatives

• Jinming Guan,
• Matthew Hachey,
• Lekha Puri,
• Vanessa Howieson,
• Kevin J. Saliba and
• Karine Auclair

Beilstein J. Org. Chem. 2016, 12, 963–968, doi:10.3762/bjoc.12.95

• pantothenamides may mimic pantetheine and are extended into a thiol-lacking coenzyme A (CoA) derivative by some of the natural CoA biosynthetic enzymes (pantothenate kinase or PanK, phosphopantetheine adenylyltransferase and dephosphocoenzyme A kinase). The resulting inactive CoA analog affects downstream

1H-Imidazol-4(5H)-ones and thiazol-4(5H)-ones as emerging pronucleophiles in asymmetric catalysis

• Antonia Mielgo and
• Claudio Palomo

Beilstein J. Org. Chem. 2016, 12, 918–936, doi:10.3762/bjoc.12.90

• for the preparation of organosulfur compounds render thioether derivatives [96][97], this approach provides products with a free thiol group such as the α-mercaptocarboxylic acid derivative 67 (Scheme 11). Additionally, these mercapto derivatives can also be S-alkylated by treatment with the

Interactions between 4-thiothymidine and water-soluble cyclodextrins: Evidence for supramolecular structures in aqueous solutions

• Vito Rizzi,
• Sergio Matera,
• Paola Semeraro,
• Paola Fini and
• Pinalysa Cosma

Beilstein J. Org. Chem. 2016, 12, 549–563, doi:10.3762/bjoc.12.54

• -mediated hydrogen bonds, involving the thiol moiety [61]. In other words when DIMEB CD was used, the presence of both CH3 and OH moieties induced a tight host–guest interaction in which the C=S group is coordinated outside the cavity through hydroxy groups via H bonds. Conclusions With the prospect to

(Thio)urea-mediated synthesis of functionalized six-membered rings with multiple chiral centers

• Giorgos Koutoulogenis,
• Nikolaos Kaplaneris and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2016, 12, 462–495, doi:10.3762/bjoc.12.48

• loading. The authors proposed a bifunctional mode of activation. More specifically, the thiourea moiety activates the maleimide through hydrogen-bonding and the tertiary amine recognizes the thiol group, again through hydrogen-bonding, and orients the thiol attacking from the Si-face of the maleimides 52

• were obtained in good to excellent yields (up to 96%) and moderate to excellent selectivities. In 2010, Chen, Xiao and co-workers described a domino sulfa-Michael–Michael reaction catalyzed by the novel multifunctional thiourea 171 (Scheme 56) [77]. The cascade is initiated by the addition of thiol 173

Optimized methods for preparation of 6^I-(ω-sulfanyl-alkylene-sulfanyl)-β-cyclodextrin derivatives

• Eva Bednářová,
• Simona Hybelbauerová and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2016, 12, 349–352, doi:10.3762/bjoc.12.38

• Prague, Hlavova 8, 128 43, Prague 2, Czech Republic 10.3762/bjoc.12.38 Abstract A general high-yielding method for the preparation of monosubstituted β-cyclodextrin derivatives which have attached a thiol group in position 6 is described. The thiol group is attached through linkers of different lengths

• disulfide can be used directly for functionalization of a gold surface, but its reduction to thiol was not described. In any case, the amide-containing derivative might not be stable enough under basic conditions needed for the polydopamine derivatization by the thiol. Besides, the common problem with the

• (disulfides 6a–g) are quite stable compounds and were prepared in quantitative yield just by bubbling air through the water/methanol solution of the thiol which was basified by addition of aqueous ammonia. The disulfides 6 can be used, as well as the thiols, for the attachment of the cyclodextrin cavity to a

Mycothiol synthesis by an anomerization reaction through endocyclic cleavage

• Shino Manabe and
• Yukishige Ito

Beilstein J. Org. Chem. 2016, 12, 328–333, doi:10.3762/bjoc.12.35

• occurrence of multiple-drug-resistant (MDR), extensive-drug-resistant (EDR), and totally drug-resistant (TDR) pathogens has increased the need for new drug candidates for treating tuberculosis. Mycothiol (MSH) 1 is the main low-molecular-weight thiol found in most actinomycetes, including Mycobacteria and

• analyses and computational calculations [11][12]. Recently, N-acyl variants of MSH homologs, such as formyl, propanoyl, and succinoyl, have been reported [13][14][15]. Gram-negative bacteria and most Eukaryotes utilize glutathione as a low-molecular-weight thiol for maintaining a reducing environment in

• the cytosol. Gram-positive bacteria including actinomycetes lack glutathione, instead, MSH is found as the major low-molecular-weight thiol. It is considered that MSH is required for maintaining a reducing intracellular environment in Gram-positive bacteria, similar to glutathione in eukaryotes and

Active site diversification of P450cam with indole generates catalysts for benzylic oxidation reactions

• Paul P. Kelly,
• Anja Eichler,
• Susanne Herter,
• David C. Kranz,
• Nicholas J. Turner and
• Sabine L. Flitsch

Beilstein J. Org. Chem. 2015, 11, 1713–1720, doi:10.3762/bjoc.11.186

• histidine were not among the active site residues of the parent (or wild type) enzyme but appeared in several of the new variants, thus introducing a thiol, polar or basic group where previously none existed. More bulky aromatic side chains in libraries I and II were often substituted for smaller side

Preparative semiconductor photoredox catalysis: An emerging theme in organic synthesis

• David W. Manley and
• John C. Walton

Beilstein J. Org. Chem. 2015, 11, 1570–1582, doi:10.3762/bjoc.11.173

• . Recently Greaney and co-workers discovered that thiols 45 were also suitable donors with photoactivated TiO2 [67]. The thiol radical cations, formed on hole capture by the thiols, lost protons and generated thiyl radicals (Scheme 10). Benzenethiol, thiophenols and n-alkylthiols all afforded reduced alkene

One-pot odourless synthesis of thioesters via in situ generation of thiobenzoic acids using benzoic anhydrides and thiourea

• Mohammad Abbasi and
• Reza Khalifeh

Beilstein J. Org. Chem. 2015, 11, 1265–1273, doi:10.3762/bjoc.11.141

• many uses in organic synthesis as intermediates, mild acyl transfer agents and thiol sources [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Thioesters can be synthesized in the laboratory by means of different methods using diverse reagents and substrates [20][21][22][23][24][25

• ][26]. The reaction of active carboxylic acid derivatives with thiols [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41] and the coupling of thiols with carboxylic acids using activating agents [42][43][44][45] have been mainly used for the synthesis of thioesters in organic synthesis. Thiol

Advances in the synthesis of functionalised pyrrolotetrathiafulvalenes

• Luke J. O’Driscoll,
• Sissel S. Andersen,
• Marta V. Solano,
• Dan Bendixen,
• Morten Jensen,
• Troels Duedal,
• Jess Lycoops,
• Cornelia van der Pol,
• Rebecca E. Sørensen,
• Karina R. Larsen,
• Kenneth Myntman,
• Christian Henriksen,
• Stinne W. Hansen and
• Jan O. Jeppesen

Beilstein J. Org. Chem. 2015, 11, 1112–1122, doi:10.3762/bjoc.11.125

• bearing a 2-cyanoethyl-protected thiol The 2-cyanoethyl protecting group offers a convenient means of synthesising MPTTFs where one or both of R1 and R2 are thioethers. When only simple alkyl thioethers are targeted, it is often more effective to incorporate these moieties prior to the cross-coupling step

• ) (EtO)3P, 120–135 °C, 1–4 h, 70–87%. Deprotection and methylation of cyanoethyl-protected thiol moieties on MPTTFs as reported by Jeppesen et al. [25]. Reagents and conditions: a) (i) 1 equiv CsOH·H2O, MeOH, THF, rt, 1 h, (ii) MeI, THF, rt, 30 min; b) (i) 1 equiv CsOH·H2O, MeOH, THF, rt, 1 h, (ii) MeI

• , THF, rt, 45 min, (iii) 1 equiv CsOH·H2O, MeOH, THF, rt, 1 h, (iv) MeI, THF, rt, 30 min. Deprotection and alkylation of cyanoethyl-protected thiol moieties on MPTTFs using CsOH·H2O or DBU. Reagents and conditions are detailed in Table 2. Deprotection and N-arylation of tosylated MPTTFs. Reagents and

Single-molecule conductance of a chemically modified, π-extended tetrathiafulvalene and its charge-transfer complex with F₄TCNQ

• Raúl García,
• M. Ángeles Herranz,
• Edmund Leary,
• M. Teresa González,
• Gabino Rubio Bollinger,
• Marius Bürkle,
• Linda A. Zotti,
• Yoshihiro Asai,
• Fabian Pauly,
• Juan Carlos Cuevas,
• Nicolás Agraït and
• Nazario Martín

Beilstein J. Org. Chem. 2015, 11, 1068–1078, doi:10.3762/bjoc.11.120

• wire using two thioacetate anchoring groups [13], most of the TTF derivatives synthesized for this purpose have been functionalized with sulfur atoms as alligator clips. These belong either to a fused ring on the TTF [14], or to a chain covalently connected to the TTF core bearing a thiol group at the

• complex and one of the terminal thiol groups. We observed a similar feature for the neutral molecule (see Figure 4b and Figure 4c) although for the neutral molecule, this signal was never very reproducible. The low group, on the other hand, fits well with conductance taking place across the whole molecule

• (i.e., thiol to thiol). We calculate an S–S distance of 2.4 nm for the CT complex (substituting the dihydroanthracene core of compound 5 for anthracene). We estimate the amount of gold retraction to be 0.5 nm, which then gives a real Au–Au separation of 1.64 ± 0.30 nm for the mean breaking distance of

Mechanical stability of bivalent transition metal complexes analyzed by single-molecule force spectroscopy

• Manuel Gensler,
• Christian Eidamshaus,
• Maurice Taszarek,
• Hans-Ulrich Reissig and
• Jürgen P. Rabe

Beilstein J. Org. Chem. 2015, 11, 817–827, doi:10.3762/bjoc.11.91

• gold coated SFM cantilever probes and surfaces using thiol chemistry (for details see Experimental section below). The interaction between gold and SH-groups is known to withstand rupture forces in the range of 1 to 2 nN [38], followed by the formation of a monoatomic gold nanowire that finally leads

DNA display of glycoconjugates to emulate oligomeric interactions of glycans

• Alexandre Novoa and
• Nicolas Winssinger

Beilstein J. Org. Chem. 2015, 11, 707–719, doi:10.3762/bjoc.11.81

• ]. The first method reported was leveraged on a nucleophilic coupling between readily available glycosyl thiol (obtained in one step by treatment of a native carbohydrate with Lawesson’s reagent [37]) and a chloroacetamide-functionalized PNA (Scheme 7) [38][39]. Using this method, we have shown that

Synthesis of 1,2-cis-2-C-branched aryl-C-glucosides via desulfurization of carbohydrate based hemithioacetals

• Henok H. Kinfe,
• Fanuel M. Mebrahtu,
• Mandlenkosi M. Manana,
• Kagiso Madumo and
• Mokela S. Sokamisa

Beilstein J. Org. Chem. 2015, 11, 583–588, doi:10.3762/bjoc.11.64

• defensive low molecular weight thiol [7]. 2-C-acetamide and 2-C-acetonyl carbohydrate derivatives have also been reported to serve as inhibitors of the biosynthesis of lipids [8][9] and cell surface engineering [10], respectively. The main synthetic protocols for the synthesis of 2-C-branched sugars involve

Diastereoselective and enantioselective conjugate addition reactions utilizing α,β-unsaturated amides and lactams

• Katherine M. Byrd

Beilstein J. Org. Chem. 2015, 11, 530–562, doi:10.3762/bjoc.11.60

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

• related compounds, such as various amino alcohols and the thiol-functional amino acid cysteine. While the basic methodology underlying this approach has been known for decades, it has evolved through recent developments connected to amino acid-derived chiral organocatalysts to become a more widely

Natural phenolic metabolites with anti-angiogenic properties – a review from the chemical point of view

• Qiu Sun,
• Jörg Heilmann and
• Burkhard König

Beilstein J. Org. Chem. 2015, 11, 249–264, doi:10.3762/bjoc.11.28

• basic condition. 4-Amino-2-sulfanylphenol derivatives The class of 4-amino-2-sulfanylphenols is obviously an outlier among the reviewed compounds, as the 2-sulfanylphenol substructure is not a structural element in natural products. The vast majority of thiol groups in secondary metabolites derive from

• the amino acid cysteine, producing aliphatic secondary metabolites with thiol functionalities instead of phenolic ones. Nevertheless, this class contains thio-analogs of the naturally occurring o-catechol substructure, and thus, it has been included in this review. Zhang and Xu et al. [51] have

An improved procedure for the preparation of Ru(bpz)₃(PF₆)₂ via a high-yielding synthesis of 2,2’-bipyrazine

• Danielle M. Schultz,
• James W. Sawicki and
• Tehshik P. Yoon

Beilstein J. Org. Chem. 2015, 11, 61–65, doi:10.3762/bjoc.11.9

• is an effective photocatalyst in oxidatively induced photoredox transformations where less strongly oxidizing complexes (e.g., 1) are not successful. For instance, we have reported that 2 is uniquely capable of promoting radical cation mediated Diels–Alder cycloadditions [12], radical thiol–ene

Organic chemistry on surfaces: Direct cyclopropanation by dihalocarbene addition to vinyl terminated self-assembled monolayers (SAMs)

• Malgorzata Adamkiewicz,
• David O’Hagan and
• Georg Hähner

Beilstein J. Org. Chem. 2014, 10, 2897–2902, doi:10.3762/bjoc.10.307

• including azide–alkyne cycloadditions [9][10], Diels–Alder reactions [11][12], maleimide–thiol reactions [13], thiol–ene additions [14], and imine/oxime conjugations [15]. In this article we demonstrate that dihalocarbenes can be used to generate dihalocyclopropanes on olefin terminated SAMs. We recently

Copper-promoted hydration and annulation of 2-fluorophenylacetylene derivatives: from alkynes to benzo[b]furans and benzo[b]thiophenes

• Yibiao Li,
• Liang Cheng,
• Xiaohang Liu,
• Bin Li and
• Ning Sun

Beilstein J. Org. Chem. 2014, 10, 2886–2891, doi:10.3762/bjoc.10.305

• nucleophilic annulation process (Scheme 1b) [24]. But this method involves a two-step process and the usage of two different metal salts may complicate further processing. The direct design of a Pd or Cu-catalyzed one-pot synthesis of benzo[b]thiophenes from 2-bromoalkynylbenzenes and a thiol derivative has