A novel approach to oxoisoaporphine alkaloids via regioselective metalation of alkoxy isoquinolines

• Benedikt C. Melzer and
• Franz Bracher

Beilstein J. Org. Chem. 2017, 13, 1564–1571, doi:10.3762/bjoc.13.156

• the presence of silver oxide), phenols 4 and 5 were converted into the alkaloids 2 and 3 in 33 and 49% yields (Scheme 9). In accordance to Kunitomo’s observations, the isomeric methoxy compounds 18 and 19 were obtained as byproducts in significant yields (Scheme 9). In order to find a more convenient

Grip on complexity in chemical reaction networks

• Albert S. Y. Wong and
• Wilhelm T. S. Huck

Beilstein J. Org. Chem. 2017, 13, 1486–1497, doi:10.3762/bjoc.13.147

• ], copyright 2006 Nature Publishing Group. (b) Minimal network motifs that describe the dynamics of minimal bistable or oscillatory systems using mass-action kinetics [49]. Belousov–Zhabotinsky (BZ) reaction. (a) Classical example of pattern formation in the BZ reaction when perturbed with a silver thread

Sugar-based micro/mesoporous hypercross-linked polymers with in situ embedded silver nanoparticles for catalytic reduction

• Qing Yin,
• Qi Chen,
• Li-Can Lu and
• Bao-Hang Han

Beilstein J. Org. Chem. 2017, 13, 1212–1221, doi:10.3762/bjoc.13.120

• reduction of 4-nitrophenol (4-NP) with an activity factor ka = 51.4 s−1 g−1, which is higher than some reported AgNP-containing composite materials. Keywords: catalytic reduction; hypercross-linking; porous polymers; silver nanoparticles; sugar; Introduction Hypercross-linked polymers (HCPs) are

• functionalization of the materials. Silver nanoparticles (AgNPs) have received extensive attention because of their unique properties and applications in catalysis [18], antibacterial use [19], phase separation [20], surface-enhanced Raman scattering (SERS) [21], etc. Compared with bulk silver, AgNPs have a more

•  3f). The weight percentage of carbon, oxygen, and silver is 85.33%, 7.21% and 7.46%, respectively. The atomic percentage of carbon, oxygen and silver is 93.18%, 5.91% and 0.91%, respectively. The as-synthesized AgNPs/SugPOP-1 composite was also characterized by X-ray diffraction (XRD) with the

Glyco-gold nanoparticles: synthesis and applications

• Federica Compostella,
• Olimpia Pitirollo,
• Alessandro Silvestri and
• Laura Polito

Beilstein J. Org. Chem. 2017, 13, 1008–1021, doi:10.3762/bjoc.13.100

• . Moreover, by using an immobilized antibody microarray, it was possible to design a highly sensitive lectin detection, enhanced by silver addition, by easy naked eye. Plasmon resonance spectroscopy and naked eye have been used by Long et al. (Figure 4) to study the interaction of galactoside-AuNPs with

Aggregation behaviour of a single-chain, phenylene-modified bolalipid and its miscibility with classical phospholipids

• Simon Drescher,
• Vasil M. Garamus,
• Christopher J. Garvey,
• Annette Meister and
• Alfred Blume

Beilstein J. Org. Chem. 2017, 13, 995–1007, doi:10.3762/bjoc.13.99

• with a wavelength λ = 1 Å. The sample-to-detector distance was 4 m, allowing for measurements in the q-range interval from 0.75 Å−1 to 5 Å−1. The q-range was calibrated using the diffraction patterns of silver behenate. The experimental data were normalized to the incident beam intensity, corrected for

Expression, purification and structural analysis of functional GABA transporter 1 using the baculovirus expression system

• Jing Hu,
• Chris Weise,
• Christoph Böttcher,
• Hua Fan and
• Jian Yin

Beilstein J. Org. Chem. 2017, 13, 874–882, doi:10.3762/bjoc.13.88

• microscopy (Figure 1B). The expression of GAT1/GFP in insect cells was further determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis SDS-PAGE, followed by Western blotting with either anti-GFP pAb (Figure 1C) or anti-GAT1 pAb (Figure 1D) and silver staining (Figure 1E) after

• fraction) from 8.8 to 11.8 mL after SE-FPLC were further analyzed by SDS-PAGE (7.5%), followed with silver staining and Western blotting (Figure 4C and 4D). The results indicated that peak 1, which should correspond to a tetrameric GAT1/GFP with a molecular weight of 320 kDa, appeared at 8.8–10.6 mL (lanes

• 2–8). Peak 2 should correspond to a dimeric form with a molecular weight of 162 kDa, but despite its strong ultraviolet (UV) absorption, it contained very little GAT1/GFP protein according to the results of silver staining, Western blot and bicinchoninic acid (BCA) assay. To prevent the protein from

Nucleophilic and electrophilic cyclization of N-alkyne-substituted pyrrole derivatives: Synthesis of pyrrolopyrazinone, pyrrolotriazinone, and pyrrolooxazinone moieties

• Işıl Yenice,
• Sinan Basceken and
• Metin Balci

Beilstein J. Org. Chem. 2017, 13, 825–834, doi:10.3762/bjoc.13.83

• presence of silver nitrate. The synthesized acetylenes 10a,b and commercially available acetylenes 10c,d were converted into bromoalkyne derivatives 11a–d according to the literature procedure (Scheme 1) [29][30]. After the successful generation of alkynyl bromides 11a–d, the next step was the synthesis of

A practical and efficient approach to imidazo[1,2-a]pyridine-fused isoquinolines through the post-GBB transformation strategy

• Taofeng Shao,
• Zhiming Gong,
• Tianyi Su,
• Wei Hao and
• Chao Che

Beilstein J. Org. Chem. 2017, 13, 817–824, doi:10.3762/bjoc.13.82

• acetylene unit may then undergo a sequential 6-exo-dig cyclization/retro-ene reaction to form the desired imidazo[1,2-a]pyridine-fused isoquinoline 6a. The cyclization reaction could be realized with the aid of silver or gold catalysts [51][52]. With this idea in mind, we commenced our studies by

Ultrasound-promoted organocatalytic enamine–azide [3 + 2] cycloaddition reactions for the synthesis of ((arylselanyl)phenyl-1H-1,2,3-triazol-4-yl)ketones

• Gabriel P. Costa,
• Natália Seus,
• Juliano A. Roehrs,
• Raquel G. Jacob,
• Ricardo F. Schumacher,
• Thiago Barcellos,
• Rafael Luque and
• Diego Alves

Beilstein J. Org. Chem. 2017, 13, 694–702, doi:10.3762/bjoc.13.68

• most attractive way for their preparation is the thermal 1,3-dipolar cycloaddition of alkynes and azides, introduced by Huisgen which usually gives rise to a mixture of 1,4 and 1,5-isomers [16][17][18][19]. More recently, transition metal catalysts based on copper, ruthenium, silver and iridium salts

Effect of the ortho-hydroxy group of salicylaldehyde in the A³ coupling reaction: A metal-catalyst-free synthesis of propargylamine

• Sujit Ghosh,
• Kinkar Biswas,
• Suchandra Bhattacharya,
• Pranab Ghosh and
• Basudeb Basu

Beilstein J. Org. Chem. 2017, 13, 552–557, doi:10.3762/bjoc.13.53

• known as A3 coupling reaction, remains the most common and straightforward method for the synthesis of propargylamine. The A3 coupling reaction is reported under transition-metal-catalyzed conditions using copper [12][17][18][19], gold [17][20][21], silver [17][22], zinc [17][23], nickel [24], iron [25

Adsorption of RNA on mineral surfaces and mineral precipitates

• Elisa Biondi,
• Yoshihiro Furukawa,
• Jun Kawai and
• Steven A. Benner

Beilstein J. Org. Chem. 2017, 13, 393–404, doi:10.3762/bjoc.13.42

• contaminants [28], aragonite is not formed. We easily reproduced this general result, establishing the structure of the precipitated phases that we obtained by both staining with Feigl’s stain (silver sulfate and manganese sulfate) [29] and by powder X-ray diffraction. To complete our analysis of the CaCO3

• clean tubes and radioactive counts in each slide were read at the scintillation counter with the Cherenkov method. Feigl’s staining and X-ray powder diffraction Feigl’s stain [29] is a solution of silver and manganese sulfates. The stain colors orthorhombic and hexagonal carbonates black, but does not

• stain trigonal carbonates, in the first 30–60 minutes. The reagent was made with 1% silver sulfate (w/v) and 12% manganese sulfate in H2O. In the staining experiments, samples were obtained by double decomposition reaction by mixing aqueous solutions of Na2CO3 (200 µL, 1 M) and CaCl2 (200 µL, 1 M

Decarboxylative and dehydrative coupling of dienoic acids and pentadienyl alcohols to form 1,3,6,8-tetraenes

• Ghina’a I. Abu Deiab,
• Mohammed H. Al-Huniti,
• I. F. Dempsey Hyatt,
• Emma E. Nagy,
• Kristen E. Gettys,
• Sommayah S. Sayed,
• Christine M. Joliat,
• Paige E. Daniel,
• Rupa M. Vummalaneni,
• Andrew T. Morehead Jr,
• Andrew L. Sargent and
• Mitchell P. Croatt

Beilstein J. Org. Chem. 2017, 13, 384–392, doi:10.3762/bjoc.13.41

• ], nitro [26][27], or alkyne [21][28][29][30][31][32], Scheme 1), or use an aryl carboxylate [33][34] which typically requires the assistance of silver or copper(I) salts for the decarboxylative step. It is rare to use a pentadienyl electrophile [35], or to have a diene or simple alkene adjacent to the

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

• found that the 3,5-DTBS-protected L-arabinosyl donor 69 upon reaction with acceptor 70 and activation with NIS/silver triflate gave exclusively the β-glycoside in a yield of 94% (Scheme 14). Similarly, the reaction of 70 with the corresponding perbenzylated donor only gave a 2:1 β:α-ratio of 71 [60]. It

Symmetry-based approach to oligostilbenoids: Rapid entry to viniferifuran, shoreaphenol, malibatol A, and diptoindonesin G

• Youngeun Jung,
• Dileep Kumar Singh and
• Ikyon Kim

Beilstein J. Org. Chem. 2016, 12, 2689–2693, doi:10.3762/bjoc.12.266

• -dimethoxybenzaldehyde, and 3,5-dimethoxybenzyl alcohol under the influence of either I2/silver trifluoroacetate or N-iodosuccinimide afforded 1 [32][33][34], 2 [35], and 7 [36][37], respectively (Scheme 2). The hydroxy group of 7 was protected as an acetate, providing 3 in 96% yield. Sonogashira coupling of the

Facile synthesis of a 3-deazaadenosine phosphoramidite for RNA solid-phase synthesis

• Elisabeth Mairhofer,
• Elisabeth Fuchs and
• Ronald Micura

Beilstein J. Org. Chem. 2016, 12, 2556–2562, doi:10.3762/bjoc.12.250

• procedures [32] unfortunately failed. We encountered these problems already in our previously published synthesis for N6-benzoyl protected c3A phosphoramidite [16], and therefore, we decided to apply triisopropylsilyl chloride (TIPS-Cl) and silver nitrate which resulted in the desired 2’-O-TIPS protected

A new protocol for the synthesis of 4,7,12,15-tetrachloro[2.2]paracyclophane

• Donghui Pan,
• Yanbin Wang and
• Guomin Xiao

Beilstein J. Org. Chem. 2016, 12, 2443–2449, doi:10.3762/bjoc.12.237

• sodium hydroxide solution instead of silver oxide for anion exchange, results in a significant improvement in product yield. Furthermore, four substituted [2.2]paracyclophanes were also prepared in this convenient way. Keywords: bromination; dimerization; H2O2–HBr system; paracyclophane; polymerization

• with silver oxide for anion exchange was used [17], and it was comparable to the commercial synthetic protocol with 36.5% yield [20]. Although two isomers from the dimerization reaction could be formed, only the 4,7,12,15-tetrachloro isomer was obtained. The structure of the product was confirmed by 1H

• with silver oxide used for anion exchange reported by Chow [17]. We speculated that the replacement of silver oxide by aqueous sodium hydroxide solution might promote the formation of substituted (4-methylbenzyl)trimethylammonium hydroxide, but we are unable to provide any conclusive evidence at

Silica-supported sulfonic acids as recyclable catalyst for esterification of levulinic acid with stoichiometric amounts of alcohols

• Raimondo Maggi,
• N. Raveendran Shiju,
• Veronica Santacroce,
• Giovanni Maestri,
• Franca Bigi and
• Gadi Rothenberg

Beilstein J. Org. Chem. 2016, 12, 2173–2180, doi:10.3762/bjoc.12.207

• catalysts. In the literature, methods that use solid heteropolyacids, such as ammonium or mixed ammonium and silver-doped phosphotungstic acid, sulfated metal oxides (such as sulfated titania, sulfated zirconia), zeolites and hydrotalcites have been reported [24][25][26][27][28][29][30]. These solid

Stereo- and regioselectivity of the hetero-Diels–Alder reaction of nitroso derivatives with conjugated dienes

• Lucie Brulíková,
• Aidan Harrison,
• Marvin J. Miller and
• Jan Hlaváč

Beilstein J. Org. Chem. 2016, 12, 1949–1980, doi:10.3762/bjoc.12.184

• the corresponding hydroxamic acids using, for example, periodate [14], Dess–Martin periodinane [64], Swern oxidation conditions [65], lead and silver oxide [66], and transition-metal oxidation with peroxide as the oxidant [67]. In a recent work by Tusun dirhodium caprolactamate [68], and the aerobic

Synthesis and characterization of fluorinated azadipyrromethene complexes as acceptors for organic photovoltaics

• Forrest S. Etheridge,
• Roshan J. Fernando,
• Sandra Pejić,
• Matthias Zeller and
• Geneviève Sauvé

Beilstein J. Org. Chem. 2016, 12, 1925–1938, doi:10.3762/bjoc.12.182

• 40 mg/mL, 1:0.8 donor-to-acceptor ratio, were spun coat at 800 rpm for 40 s and 2000 rpm for 2 s and annealed at 120 °C for 15 min. Molybdenum oxide (10 nm) and silver (80 nm) were thermally evaporated in sequence under a vacuum pressure of ≈3 × 10−6 Torr using an Angstrom Engineering Evovac thermal

Practical synthetic strategies towards lipophilic 6-iodotetrahydroquinolines and -dihydroquinolines

• David R. Chisholm,
• Garr-Layy Zhou,
• Ehmke Pohl,
• Roy Valentine and
• Andrew Whiting

Beilstein J. Org. Chem. 2016, 12, 1851–1862, doi:10.3762/bjoc.12.174

• in much lower yield and only negligible amounts (1–2%) of the iPr adduct were isolated. Alkylation using silver(I) oxide was also possible, but with similarly low yields. The ortho-methyl group had originally been incorporated as protection to block the ortho-amino centre against oxidation [14], and

• detector. Apodization = Happ General. Probe: Prob A DiComp (Diamond) connected via KAgX 9.5 mm × 2 m Fiber (Silver Halide); Sampling 2000–650 at 8 cm−1 resolution; Scan option: auto select, gain 1X. X-ray crystallography Single-crystal diffraction experiments were conducted on a Bruker APEX-II CCD

On the cause of low thermal stability of ethyl halodiazoacetates

• Magnus Mortén,
• Martin Hennum and
• Tore Bonge-Hansen

Beilstein J. Org. Chem. 2016, 12, 1590–1597, doi:10.3762/bjoc.12.155

• highly solvent dependent (Table 1, entries 2, 8–11). One obvious reason for the lower stability in CDCl3 could be the presence of trace amounts of acid in the used CDCl3. However, newly purchased CDCl3 that was stored in the fridge over silver foil and 4 Å molecular sieves in order to remove any trace of

Methylpalladium complexes with pyrimidine-functionalized N-heterocyclic carbene ligands

• Dirk Meyer and
• Thomas Strassner

Beilstein J. Org. Chem. 2016, 12, 1557–1565, doi:10.3762/bjoc.12.150

• = Cl, CF3COO, CH3) has been prepared by transmetalation reactions from the corresponding silver complexes and chloro(methyl)(cyclooctadiene)palladium(II). The dimethyl(1-(2-pyrimidyl)-3-(2,6-diisopropylphenyl)imidazolin-2-ylidene)palladium(II) complex was synthesized via the free carbene route. All

• reported the synthesis of the imidazolium salts 1–4 and their corresponding silver complexes 5–8. The reaction with dichloro(cyclooctadiene)-palladium(II) [(COD)PdIICl2] allowed for the isolation and characterization of the [((pym)^(NHC-R))PdIICl2]-complexes [34]. For the synthesis of the corresponding

• silver complexes 5–8 by transmetalation with chloro(methyl)(cyclooctadiene)palladium(II) [(COD)PdII(CH3)Cl] either in dichloromethane (A) or acetonitrile (B, Scheme 1). Although two isomers could be formed we only observed the isomer B, where the methyl group is located cis to the carbene carbon atom

Development of chiral metal amides as highly reactive catalysts for asymmetric [3 + 2] cycloadditions

• Yasuhiro Yamashita,
• Susumu Yoshimoto,
• Mark J. Dutton and
• Shū Kobayashi

Beilstein J. Org. Chem. 2016, 12, 1447–1452, doi:10.3762/bjoc.12.140

• developed asymmetric [3 + 2] cycloadditions [4][5][6][7][8] and asymmetric Mannich-type reactions [9] by using chiral silver or copper amides as catalysts. In these reactions, it has been revealed that the metal amides have higher activity than typical silver or copper acid/base catalysts, and that less

Multicomponent reactions: A simple and efficient route to heterocyclic phosphonates

• Mohammad Haji

Beilstein J. Org. Chem. 2016, 12, 1269–1301, doi:10.3762/bjoc.12.121

• phosphorylated quinazoline 203 through reductive elimination. A silver-catalyzed three-component reaction of α-isocyanophosphonates 206, ketones 205 and amines 204 under microwave irradiation to afford (2-imidazolin-4-yl)phosphonates 210 has recently been reported (Scheme 43) [81]. The yields of the products

• under optimized conditions were 53–89%. This process involved a Mannich-type addition of a silver-activated α-isocyanophosphonate anion 208 to an iminium salt 207, resulting from reaction of amine 204 and ketone 205, to give intermediate 209 which cyclizes to afford (2-imidazolin-4-yl)phosphonates 210

• -component reaction of acylphosphonates, isocyanides and dialkyl acetylenedicarboxylate to afford 2-phosphonofuran derivatives. Synthesis of (4-imino-3,4-dihydroquinazolin-2-yl)phosphonates via an isocyanide-based three-component reaction. Silver-catalyzed three-component synthesis of (2-imidazolin-4-yl

Efficient syntheses of climate relevant isoprene nitrates and (1R,5S)-(−)-myrtenol nitrate

• Sean P. Bew,
• Glyn D. Hiatt-Gipson,
• Graham P. Mills and
• Claire E. Reeves

Beilstein J. Org. Chem. 2016, 12, 1081–1095, doi:10.3762/bjoc.12.103

• 7TJ, UK 10.3762/bjoc.12.103 Abstract Here we report the chemoselective synthesis of several important, climate relevant isoprene nitrates using silver nitrate to mediate a ’halide for nitrate’ substitution. Employing readily available starting materials, reagents and Horner–Wadsworth–Emmons chemistry

• the C=C derived O-nitrates focuses on a report by Scheinbaum and Dines who established that alkenes in the presence of acetonitrile and 22 undergo a Ritter reaction affording vicinal nitro acetamido species [29]. Silver nitrate reacts with alkyl, benzyl or acyl halides affording the corresponding

• alkyl [30], benzyl [31][32] or acyl nitrates [33]. By way of example and relevant to the work reported here Ogawa et al. [34] transformed bromoacetone to 2-oxopropyl nitrate (component of climate mediated IPN decomposition [35]) using silver nitrate in acetonitrile. Initiating the synthesis of ‘test