Solid-phase enrichment and analysis of electrophilic natural products

• Frank Wesche,
• Yue He and
• Helge B. Bode

Beilstein J. Org. Chem. 2017, 13, 405–409, doi:10.3762/bjoc.13.43

• dehydroalanine [6][7], ketones, aldehydes [8][9], carboxylic acids [8][9], amines [8][9][10], thiols [8][9], alcohols [11], epoxides [12], terminal alkynes [13][14] and azides [15] can be targeted to introduce a label. Such labels might increase the visibility in UV or MS detection in liquid chromatography

Polyketide stereocontrol: a study in chemical biology

• Kira J. Weissman

Beilstein J. Org. Chem. 2017, 13, 348–371, doi:10.3762/bjoc.13.39

• product structures by gas-chromatography/mass spectrometry (GC–MS) and liquid chromatography (LC)–MS. Review Biosynthesis of complex polyketides by modular PKSs and stereochemical considerations The reduced or complex class of polyketides is assembled in bacteria by gigantic multienzymes called polyketide

NMR reaction monitoring in flow synthesis

• M. Victoria Gomez and
• Antonio de la Hoz

Beilstein J. Org. Chem. 2017, 13, 285–300, doi:10.3762/bjoc.13.31

• in which the WET sequence is incorporated into the end of the mix delay. NMR spectroscopy can be coupled to most separation techniques, including gas chromatography (GC), supercritical fluid chromatography (SFC), gel-permeation chromatography (GPC), high-performance liquid chromatography (HPLC

Total synthesis of a Streptococcus pneumoniae serotype 12F CPS repeating unit hexasaccharide

• Peter H. Seeberger,
• Claney L. Pereira and
• Subramanian Govindan

Beilstein J. Org. Chem. 2017, 13, 164–173, doi:10.3762/bjoc.13.19

• -dimethylformamide; EtOAc: ethyl acetate; GlcA: glucouronic acid; HPLC: high-performance liquid chromatography; Lev: levulinoyl; MALDI–TOF MS: matrix-assisted laser desorption/ionization–time of flight mass spectrometry; NAP: 2-naphthylmethyl; TBS: tert-butyldimethylsilyl; THF: tetrahydrofuran; TMSOTf

3D printed fluidics with embedded analytic functionality for automated reaction optimisation

• Andrew J. Capel,
• Andrew Wright,
• Matthew J. Harding,
• George W. Weaver,
• Yuqi Li,
• Russell A. Harris,
• Steve Edmondson,
• Ruth D. Goodridge and
• Steven D. R. Christie

Beilstein J. Org. Chem. 2017, 13, 111–119, doi:10.3762/bjoc.13.14

• to fully utilise this flexibility, parts were designed which could be integrated with existing flow and analytical instrumentation. An ideal choice for this application is high-performance liquid chromatography (HPLC). HPLC instrumentation is widely available in most modern chemistry laboratories

Formose reaction controlled by boronic acid compounds

• Toru Imai,
• Tomohiro Michitaka and
• Akihito Hashidzume

Beilstein J. Org. Chem. 2016, 12, 2668–2672, doi:10.3762/bjoc.12.263

• recovered by freeze-drying, and characterized by high-performance liquid chromatography (HPLC) using an amino column and a mixed solvent of water and acetonitrile, as can be seen in Figure 2. As reference, this figure also contains an HPLC chart for standard samples, i.e., two-, three-, four-, five-, and

Formose reaction accelerated in aerosol-OT reverse micelles

• Makoto Masaoka,
• Tomohiro Michitaka and
• Akihito Hashidzume

Beilstein J. Org. Chem. 2016, 12, 2663–2667, doi:10.3762/bjoc.12.262

• reverse micelles. However, it was not possible to purify the product because the reaction mixture contained a large amount of AOT. After a large fraction of AOT was removed, the mixture obtained was measured by high-performance liquid chromatography, NMR spectroscopy, and mass spectrometry, but no signals

Methylenelactide: vinyl polymerization and spatial reactivity effects

• Judita Britner and
• Helmut Ritter

Beilstein J. Org. Chem. 2016, 12, 2378–2389, doi:10.3762/bjoc.12.232

• copolymerization parameters of MLA with styrene and MMA, respectively were evaluated through the method of Kelen and Tüdös [18]. For this, the residual monomer ratio was determined by high performance liquid chromatography (see execution, characterization methods and Figures S14 and S15 in Supporting Information

Determination of the absolute stereostructure of a cyclic azobenzene from the crystal structure of the precursor containing a heavy element

• Reji Thomas and
• Nobuyuki Tamaoki

Beilstein J. Org. Chem. 2016, 12, 2211–2215, doi:10.3762/bjoc.12.212

• ionization time-of-flight mass spectrometry (MALDI–TOFMS) was performed with an Applied Biosystems Voyager-DE pro instrument. Absorption spectra were recorded with an Agilent 8453 spectrophotometer and the CD spectra were recorded with a JASCO J-S720 CD spectrophotometer. High-performance liquid

• chromatography (HPLC) was conducted with a Hitachi Elite La Chrome HPLC system using CHIRALPAK IA (DAICEL Chemical Industries Ltd.) column with solvent mixtures of ethyl acetate in hexane, 10:90 as eluent for the HPLC experiments at a flow rate of 3 mL/min. Reductive debromination of compound (E)-1B To a

Rh-Catalyzed reductive Mannich-type reaction and its application towards the synthesis of (±)-ezetimibe

• Motoyuki Isoda,
• Kazuyuki Sato,
• Yurika Kunugi,
• Satsuki Tokonishi,
• Atsushi Tarui,
• Masaaki Omote,
• Hideki Minami and
• Akira Ando

Beilstein J. Org. Chem. 2016, 12, 1608–1615, doi:10.3762/bjoc.12.157

• on JEOL JMS-700T spectrometers. IR spectra were recorded on a Hitachi 270-30 infrared spectrophotometer. Melting points were measured on a Yanagimoto micro melting point apparatus MP-S3. Analytical gas–liquid chromatography (GLC) was carried out on a Hitachi G-3500 gas chromatograph (column; TC-5

Separation and identification of indene–C₇₀ bisadduct isomers

• Bolong Zhang,
• Jegadesan Subbiah,
• David J. Jones and
• Wallace W. H. Wong

Beilstein J. Org. Chem. 2016, 12, 903–911, doi:10.3762/bjoc.12.88

• –C70 bisadduct (IC70BA) mixture, we report the full fractionation and identification of the bisadduct species in the material. Eleven fractions of IC70BA isomers were separated by high-performance liquid chromatography. A number of fractions contained relatively pure isomer species and their

• device performance. In a previous communication [9], an isomer of IC70BA was obtained by chromatographic separation using both flash chromatography and high pressure liquid chromatography (HPLC). X-ray crystallography revealed that this sample contained the 2 o’clock-B isomer (Figure 2b). This material

Three new trixane glycosides obtained from the leaves of Jungia sellowii Less. using centrifugal partition chromatography

• Luíse Azevedo,
• Larissa Faqueti,
• Marina Kritsanida,
• Antonia Efstathiou,
• Despina Smirlis,
• Gilberto C. Franchi Jr,
• Grégory Genta-Jouve,
• Sylvie Michel,
• Louis P. Sandjo,
• Raphaël Grougnet and
• Maique W. Biavatti

Beilstein J. Org. Chem. 2016, 12, 674–683, doi:10.3762/bjoc.12.68

• been used in a semi-empirical mode [20] as a replacement of vacuum liquid chromatography (VLC) or reversed-phase medium pressure liquid chromatography (MPLC), permitting specially the isolation of several terpene glycosides [27], such as a geranyl disaccharide [28], natural [29][30], semisynthetic

Physical properties and biological activities of hesperetin and naringenin in complex with methylated β-cyclodextrin

• Waratchada Sangpheak,
• Jintawee Kicuntod,
• Roswitha Schuster,
• Thanyada Rungrotmongkol,
• Peter Wolschann,
• Nawee Kungwan,
• Helmut Viernstein,
• Monika Mueller and
• Piamsook Pongsawasdi

Beilstein J. Org. Chem. 2015, 11, 2763–2773, doi:10.3762/bjoc.11.297

• to appropriate concentration, and analyzed for absorbance at 286 nm by high-performance liquid chromatography (HPLC, Waters 600, USA). The dissolution studies were performed in triplicate. Determination of biological activity of flavanones Preparation of free compound and their complexes: Stock

Synthesis of cyclic N¹-pentylinosine phosphate, a new structurally reduced cADPR analogue with calcium-mobilizing activity on PC12 cells

• Ahmed Mahal,
• Stefano D’Errico,
• Nicola Borbone,
• Brunella Pinto,
• Agnese Secondo,
• Valeria Costantino,
• Valentina Tedeschi,
• Giorgia Oliviero,
• Vincenzo Piccialli and
• Gennaro Piccialli

Beilstein J. Org. Chem. 2015, 11, 2689–2695, doi:10.3762/bjoc.11.289

• 13C NMR. 31P NMR experiments were carried out on a Varian Unity INOVA 500 MHz instrument in CD3OD solvent using 85% H3PO4 as an external standard (0 ppm). High performance liquid chromatography (HPLC) was performed using a Jasco UP-2075 Plus pump equipped with a Jasco UV-2075 Plus UV detector and a

Bromotyrosine-derived alkaloids from the Caribbean sponge Aplysina lacunosa

• Qun Göthel,
• Thanchanok Sirirak and
• Matthias Köck

Beilstein J. Org. Chem. 2015, 11, 2334–2342, doi:10.3762/bjoc.11.254

• vacuum liquid chromatography using silica gel with a stepwise gradient eluent from 100:0 to 80:20 (CH2Cl2/MeOH, v/v). The two fractions eluting with 97:3 and 94:6 (CH2Cl2/MeOH, v/v) were further purified by HPLC and yielded the three new bromotyrosine derivatives 14-debromo-11-deoxyfistularin-3 (1

• partitioned between EtOAc and H2O. The EtOAc fraction was further purified by vacuum liquid chromatography using silica gel eluting with stepwise gradient from 100:0 to 80:20 (CH2Cl2/MeOH, v/v). The fraction eluted with 97:3 (CH2Cl2/MeOH, v/v) was concentrated and further purified by HPLC using an RP C18

Co-solvation effect on the binding mode of the α-mangostin/β-cyclodextrin inclusion complex

• Chompoonut Rungnim,
• Sarunya Phunpee,
• Manaschai Kunaseth,
• Supawadee Namuangruk,
• Kanin Rungsardthong,
• Thanyada Rungrotmongkol and
• Uracha Ruktanonchai

Beilstein J. Org. Chem. 2015, 11, 2306–2317, doi:10.3762/bjoc.11.251

• shaking incubator (Vision Scientific Co., Ltd., Korean) at 25 °C for 48 h to ensure equilibrium was reached. The samples were then passed through a 0.45 µm Nylon filter, and the concentration of dissolved α-mangostin was determined by high-performance liquid chromatography, HPLC, (Waters, model e2695, USA

Qualitative evaluation of regioselectivity in the formation of di- and tri-6-O-tritylates of α-cyclodextrin

• Keisuke Yoshikiyo,
• Yoshihisa Matsui and
• Tatsuyuki Yamamoto

Beilstein J. Org. Chem. 2015, 11, 1530–1540, doi:10.3762/bjoc.11.168

• ,6C-di-O-trityl-α-CD’s. Keywords: 1H and 13C NMR spectroscopy; quantitative analysis; regioselectivity; tritylation; ultra-fast liquid chromatography (UFLC); Introduction Regioselective modification and deprotection on the primary hydroxy side of cyclodextrins (CDs) are of great importance in

• direction of literature [9], and separated by means of reversed-phase column chromatography. Three regioisomers of di-6-O-trityl-α-CD obtained gave well-separated peaks in UFLC (ultra-fast liquid chromatography) experiment (Figure 1), details of which will be described in the Experimental part. Four

• pyridine was dried over CaH2 and distilled in the presence of CaH2 before use. N,N-Dimethylformamide (DMF) was also dried over CaH2 and distilled before use. Acetonitrile for high performance liquid chromatography was purchased from Wako Pure Chemical Industries Ltd. DMSO-d6 containing 0.05% v/v

Synthesis and evaluation of the biostability and cell compatibility of novel conjugates of nucleobase, peptidic epitope, and saccharide

• Dan Yuan,
• Xuewen Du,
• Junfeng Shi,
• Ning Zhou,
• Abdulgader Ahmed Baoum,
• Khalid Omar Al Footy,
• Khadija Omar Badahdah and
• Bing Xu

Beilstein J. Org. Chem. 2015, 11, 1352–1359, doi:10.3762/bjoc.11.145

• chain from the resin with 95% trifluoroacetic acid (TFA) without N-protecting groups. Later, NAS was obtained by reacting D-glucosamine hydrochloride with the fully protected NA. After cleaving the protecting group on amino acids with 95% TFA, we used reversed-phase high-performance liquid

• chromatography (HPLC) to purify the target conjugates. Gelation properties Supramolecular hydrogels [18][19][20][21][22][23][24] formed by self-assembly of small molecules in water, as demonstrated previously by us and other researchers, have numerous potential applications, such as encapsulation and delivery of

Stereoselective cathodic synthesis of 8-substituted (1R,3R,4S)-menthylamines

• Carolin Edinger,
• Jörn Kulisch and
• Siegfried R. Waldvogel

Beilstein J. Org. Chem. 2015, 11, 294–301, doi:10.3762/bjoc.11.34

• applications reported so far, are the uses as building blocks in supramolecular receptors [29][30][31][32][33][34] or the synthesis of high-performance stationary phases for liquid chromatography [35][36][37][38]. (−)-Menthone (2) can be converted to menthylamine by different methods: A general way to convert

First chemoenzymatic stereodivergent synthesis of both enantiomers of promethazine and ethopropazine

• Paweł Borowiecki,
• Daniel Paprocki and
• Maciej Dranka

Beilstein J. Org. Chem. 2014, 10, 3038–3055, doi:10.3762/bjoc.10.322

• liquid chromatography (HPLC) analysis using a Chiralcel OD-H column. The products could be analyzed directly from the crude mixture since the conditions of the HPLC chiral stationary phases were adjusted to the needs of both resolution products (peaks of the alcohol and the acetate enantiomers were well

A small azide-modified thiazole-based reporter molecule for fluorescence and mass spectrometric detection

• Stefanie Wolfram,
• Hendryk Würfel,
• Stefanie H. Habenicht,
• Christine Lembke,
• Phillipp Richter,
• Eckhard Birckner,
• Rainer Beckert and
• Georg Pohnert

Beilstein J. Org. Chem. 2014, 10, 2470–2479, doi:10.3762/bjoc.10.258

• samples. Several probes have been designed for use with liquid chromatography–mass spectrometry (LC–MS). The probes attach covalently to target functional groups like amines, aldehydes/ketones, carboxylic acids and enhance their detection limit in LC–electrospray ionization (ESI) MS. This can be achieved

• ., for biological applications. In contrast, the quantum yield of BNS (6) in 80% water/20% THF (v/v) was below 0.03 and rendering it inappropriate for this purpose. The UV properties allow UV detection after LC separation as could be shown by ultra-performance liquid chromatography (UPLC) coupled to a

New highlights of the syntheses of pyrrolo[1,2-a]quinoxalin-4-ones

• Emilian Georgescu,
• Alina Nicolescu,
• Florentina Georgescu,
• Florina Teodorescu,
• Daniela Marinescu,
• Ana-Maria Macsim and
• Calin Deleanu

Beilstein J. Org. Chem. 2014, 10, 2377–2387, doi:10.3762/bjoc.10.248

• are uncorrected. The IR spectra were recorded on a Nicolet Impact 410 spectrometer, in KBr pellets. The high performance liquid chromatography (HPLC) analyses were performed with an Agilent Chromatograph 1200 Series at room temperature by isocratic elution of acrylonitrile on an Agilent Zorbax SB-C18

Expanding the scope of cyclopropene reporters for the detection of metabolically engineered glycoproteins by Diels–Alder reactions

• Anne-Katrin Späte,
• Verena F. Schart,
• Julia Häfner,
• Andrea Niederwieser,
• Thomas U. Mayer and
• Valentin Wittmann

Beilstein J. Org. Chem. 2014, 10, 2235–2242, doi:10.3762/bjoc.10.232

• and, when feasible, assignments were supported by two-dimensional 1H,1H and 1H,13C correlation spectroscopy (COSY, HMBC and HSQC). HRMS mass spectra were obtained with a micrOTOF II instrument from Bruker Daltonics. Semi-preparative high performance liquid chromatography (HPLC) was conducted on a LC

Photoswitchable precision glycooligomers and their lectin binding

• Daniela Ponader,
• Sinaida Igde,
• Marko Wehle,
• Katharina Märker,
• Mark Santer,
• David Bléger and
• Laura Hartmann

Beilstein J. Org. Chem. 2014, 10, 1603–1612, doi:10.3762/bjoc.10.166

• File 1). Characterization of the photoswitchable properties The photochromic behavior of the newly synthesized AZO-glycooligomers was investigated by UV–vis absorption spectroscopy and ultraperformance liquid chromatography (UPLC). Aqueous solutions of Azo-Gal(1,3)-3 and Azo-Gal(1,3,5)-5 (the compounds

Glycosystems in nanotechnology: Gold glyconanoparticles as carrier for anti-HIV prodrugs

• Fabrizio Chiodo,
• Marco Marradi,
• Javier Calvo,
• Eloisa Yuste and
• Soledad Penadés

Beilstein J. Org. Chem. 2014, 10, 1339–1346, doi:10.3762/bjoc.10.136

• containing ABC or 3TC (around 10%) in 1 N HCl at different times by liquid chromatography–mass spectrometry (LC–MS, Figure 2). A solution of drugs-GNPs (2 mg/mL) in water was treated with 1 N HCl and 1:1000 dilution aliquots (10 μL) of the GNP solutions were injected into the chromatograph. The free drugs