Synthesis of the tetracyclic core of Illicium sesquiterpenes using an organocatalyzed asymmetric Robinson annulation

• Lynnie Trzoss,
• Jing Xu,
• Michelle H. Lacoske and
• Emmanuel A. Theodorakis

Beilstein J. Org. Chem. 2013, 9, 1135–1140, doi:10.3762/bjoc.9.126

• under Meerwein’s conditions to afford β-ketoester 17. Treatment of 17 with TMSOTf/Et3N followed by enolate alkylation [82] under TBAF/MeI conditions afforded the desired C-5 quaternary center of 18 as a single isomer (35% over four steps). Global reduction of 18 with lithium aluminium hydride produced

C–C Bond formation catalyzed by natural gelatin and collagen proteins

• Dennis Kühbeck,
• Basab Bijayi Dhar,
• Eva-Maria Schön,
• Carlos Cativiela,
• Vicente Gotor-Fernández and
• David Díaz Díaz

Beilstein J. Org. Chem. 2013, 9, 1111–1118, doi:10.3762/bjoc.9.123

• , 4.6 × 250 mm, 5 μm. TLC was facilitated by the use of the following stains in addition to UV light (254 nm) with fluorescent-indicating plates (aluminium sheets precoated with silica gel 60 F254, Merck): phosphomolybdic acid, vanillin, iodine. Analytical-grade solvents and commercially available

Preparation and ring-opening reactions of N-diphenylphosphinyl vinyl aziridines

• Ashley N. Jarvis,
• Andrew B. McLaren,
• Helen M. I. Osborn and
• Joseph Sweeney

Beilstein J. Org. Chem. 2013, 9, 852–859, doi:10.3762/bjoc.9.98

• or Fluka Kieselgel 60 silica. Analytical thin-layer chromatography (TLC) was performed on precoated Merck Kieselgel 60 F254 aluminium backed plates and was visualised under UV conditions at 254 nm and by staining with an acidic ammonium molybdate spray. General procedures for the synthesis of N

Quantification of N-acetylcysteamine activated methylmalonate incorporation into polyketide biosynthesis

• Stephan Klopries,
• Uschi Sundermann and
• Frank Schulz

Beilstein J. Org. Chem. 2013, 9, 664–674, doi:10.3762/bjoc.9.75

• out using Acros silica gel 60 (35–70 µm mesh). Thin-layer chromatography (TLC) was performed on aluminium-backed, precoated silica gel (60 F245) from Merck with cyclohexane/EtOAc or DCM/MeOH mixtures as mobile phases. Spots were detected by staining with KMnO4 solution (5.0 g KMnO4, 33 g K2CO3, 10 mL

Synthesis and stability study of a new major metabolite of γ-hydroxybutyric acid

• Ida Nymann Petersen,
• Jesper Langgaard Kristensen,
• Christian Tortzen,
• Torben Breindahl and
• Daniel Sejer Pedersen

Beilstein J. Org. Chem. 2013, 9, 641–646, doi:10.3762/bjoc.9.72

• . Thin-layer chromatography (TLC) was carried out on commercially available precoated aluminium sheets (Merck 60 F254). The quoted Rf values are rounded to the nearest 0.05. 1H and 13C NMR was run on a Varian Mercury 300 MHz, a Varian Gemini 300 MHz and a Bruker 500 MHz Avance III Fourier transform NMR

Thermotropic and lyotropic behaviour of new liquid-crystalline materials with different hydrophilic groups: synthesis and mesomorphic properties

• Alexej Bubnov,
• Miroslav Kašpar,
• Věra Hamplová,
• Ute Dawin and
• Frank Giesselmann

Beilstein J. Org. Chem. 2013, 9, 425–436, doi:10.3762/bjoc.9.45

• stabilisation within ±0.1 K. Phase-transition temperatures and enthalpies were determined by differential scanning calorimetry (DSC - Pyris Diamond Perkin-Elmer 7) on samples of 3–6 mg hermetically sealed in aluminium pans in cooling/heating runs in a nitrogen atmosphere at a heating/cooling rate of 5 K min−1

Asymmetric Diels–Alder reaction with >C=P– functionality of the 2-phosphaindolizine-η¹-P-aluminium(O-menthoxy) dichloride complex: experimental and theoretical results

• Rajendra K. Jangid,
• Nidhi Sogani,
• Neelima Gupta,
• Raj K. Bansal,
• Moritz von Hopffgarten and
• Gernot Frenking

Beilstein J. Org. Chem. 2013, 9, 392–400, doi:10.3762/bjoc.9.40

• , Germany 10.3762/bjoc.9.40 Abstract The Diels–Alder reaction of the 2-phosphaindolizine-η1-P-aluminium(O-menthoxy) dichloride complex with dimethylbutadiene was investigated experimentally and computationally. The >C=P– functionality of the complex reacts with 2,3-dimethylbutadiene with complete

• diastereoselectivity to afford [2 + 4] cycloadducts. Calculation of the model substrate, 3-methoxycarbonyl-1-methyl-2-phosphaindolizine-P-aluminium(O-menthoxy) dichloride (7a), at the DFT (B3LYP/6-31+G*) level reveals that the O-menthoxy moiety blocks the Re face of the >C=P– functionality, due to which the activation

• barrier of the Diels–Alder reaction of 7a with 1,3-butadiene, involving its attack from the Si face, is lower. It is found that in this case, the exo approach of the diene is slightly preferred over the endo approach. Keywords: aluminium(O-menthoxy) dichloride; asymmetric synthesis; >C=P– functionality

De novo synthesis of D- and L-fucosamine containing disaccharides

• Daniele Leonori and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2013, 9, 332–341, doi:10.3762/bjoc.9.38

• -controlled addition [49][50] of commercially available propynylmagnesium bromide to L-1 (Scheme 2A) [51][52] The following E-selective alkyne reduction was accomplished by using diluted RedAl in Et2O [53]. This reaction proved to be highly dependent on the quality of the aluminium reagent obtained from

Inclusion of the insecticide fenitrothion in dimethylated-β-cyclodextrin: unusual guest disorder in the solid state and efficient retardation of the hydrolysis rate of the complexed guest in alkaline solution

• Dyanne L. Cruickshank,
• Natalia M. Rougier,
• Raquel V. Vico,
• Susan A. Bourne,
• Elba I. Buján,
• Mino R. Caira and
• Rita H. de Rossi

Beilstein J. Org. Chem. 2013, 9, 106–117, doi:10.3762/bjoc.9.14

• differential scanning calorimetric trace was recorded on a DSC-Q200 calorimeter, TA instruments. For both techniques, a heating rate of 10 K min−1 and dry nitrogen purge gas flowing at a rate of 30 mL min−1 were employed. Crystals were transferred to an open alumina or aluminium crucible in the case of TG

• measurements and closed vented aluminium pans for DSC measurements. Sample masses were between 0.5 and 2.0 mg for DSC measurements and between 2 and 8 mg for the TG runs. Kinetic procedures The kinetic procedures were described previously [6]. The DIMEB molecule has hydroxy groups that can be deprotonated by

Iron-containing mesoporous aluminosilicate catalyzed direct alkenylation of phenols: Facile synthesis of 1,1-diarylalkenes

• Satyajit Haldar and
• Subratanath Koner

Beilstein J. Org. Chem. 2013, 9, 49–55, doi:10.3762/bjoc.9.6

• established from the small-angle XRD patterns (see Supporting Information File 1). The BET surface area and the pore width of Fe-Al-MCM-41 were found to be 753 m2/g and 25.83 Å, respectively. The aluminium and iron contents of the Fe-Al-MCM-41 catalyst were estimated by AAS method and found to be 5.5 wt % and

• alumina support “Al-MCM-41” itself was used as catalyst, the conversion recorded was only 2% (Table 2, entry 7). The aluminium-free pure mesoporous silica, MCM-41, displayed no catalytic activity, as expected (Table 2, entry 8). This clearly indicates that the presence of iron in the catalyst Fe-Al-MCM-41

• is directly related to its superior performance in the catalytic reaction. Iron probably has some role in lowering the activation energy of the reaction in synergy with the aluminium moiety present in Al-MCM-41. The short reaction time is probably due to the mesoporous structure of Fe-Al-MCM-41 (pore

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

• needle and nitrogen stream). For safety, the cooling water should be connected to a flow sensor in order to shut down the lamp should the water pressure drop. The whole apparatus can be shielded in a cabinet to avoid exposure to powerful UV radiation. Alternatively aluminium foil can be wrapped around

Synthesis of 5-oxyquinoline derivatives for reversal of multidrug resistance

• Torsten Dittrich,
• Nils Hanekop,
• Nacera Infed,
• Lutz Schmitt and
• Manfred Braun

Beilstein J. Org. Chem. 2012, 8, 1700–1704, doi:10.3762/bjoc.8.193

• spectroscopy was carried out on Bruker FT-ICR APEX III (7.0 T) (MALDI) at the University of Bielefeld. Column chromatography was performed with Fluka silica gel 60 (230–400 mesh), and thin-layer chromatography was carried out by using Merck TLC silicagel 60 F254 aluminium sheets. Toluene was freshly distilled

Enantioselective total synthesis of (R)-(−)-complanine

• Krystal A. D. Kamanos and
• Jonathan M. Withey

Beilstein J. Org. Chem. 2012, 8, 1695–1699, doi:10.3762/bjoc.8.192

• turned to its conversion to amino alcohol 4. It was envisioned that such conversion could be effected in a one-pot reaction by employing lithium aluminium hydride reduction of an aldoximine [5], formed in situ by condensation of a suitably oxygenated aldehyde 5 with hydroxylamine hydrochloride (Scheme 3

The Amadori rearrangement as glycoconjugation method: Synthesis of non-natural C-glycosyl type glycoconjugates

• Katharina Gallas,
• Gerit Pototschnig,
• Florian Adanitsch,
• Arnold E. Stütz and
• Tanja M. Wrodnigg

Beilstein J. Org. Chem. 2012, 8, 1619–1629, doi:10.3762/bjoc.8.185

• were measured on a Perkin Elmer 341 polarimeter at a wavelength of 589 nm and a path length of 10 cm at 20 °C. Analytical TLC was performed on precoated aluminium plates Silica Gel 60 F254 (E. Merck 5554), detected with UV light (254 nm), 10% vanillin/sulfuric acid and ceric ammonium molybdate (100 g

Synthesis of trifunctional cyclo-β-tripeptide templates

• Frank Stein,
• Tahir Mehmood,
• Tilman Plass,
• Javid H. Zaidi and
• Ulf Diederichsen

Beilstein J. Org. Chem. 2012, 8, 1576–1583, doi:10.3762/bjoc.8.180

• aluminium sheets silica gel 60 F254. Detection was performed under UV light (254 nm) or by dipping into a solution of ninhydrin (3% in ethanol) followed by heating with a heat gun. Eluents and the appropriate Rf values are indicated. The columns for flash chromatography were packed with silica gel 60 from

Synthesis and evaluation of new guanidine-thiourea organocatalyst for the nitro-Michael reaction: Theoretical studies on mechanism and enantioselectivity

• Tatyana E. Shubina,
• Matthias Freund,
• Sebastian Schenker,
• Timothy Clark and
• Svetlana B. Tsogoeva

Beilstein J. Org. Chem. 2012, 8, 1485–1498, doi:10.3762/bjoc.8.168

• over sodium/benzophenone and by distillation prior to use. Solvents for chromatography were distilled prior to use. TLC chromatography was performed on precoated aluminium silica gel ALUGRAM SIL G/UV254 plates (Macherey-Nagel GmbH & Co.). Flash chromatography was performed on silica gel 60 Å (Acros

A novel asymmetric synthesis of cinacalcet hydrochloride

• Veera R. Arava,
• Laxminarasimhulu Gorentla and
• Pramod K. Dubey

Beilstein J. Org. Chem. 2012, 8, 1366–1373, doi:10.3762/bjoc.8.158

• were recorded on a Perkin-Elmer spectrophotometer as KBr pellets or neat. Analytical TLC is conducted on E-Merck 60 F254 aluminium-packed silica gel plates (0.2 mm). Developed plates were visualized under UV light or in an iodine chamber. Chiral HPLC analyses were recorded with on a Waters Alliance

Synthesis of new pyrrole–pyridine-based ligands using an in situ Suzuki coupling method

• Matthias Böttger,
• Björn Wiegmann,
• Steffen Schaumburg,
• Peter G. Jones,
• Wolfgang Kowalsky and
• Hans-Hermann Johannes

Beilstein J. Org. Chem. 2012, 8, 1037–1047, doi:10.3762/bjoc.8.116

• the coupling gave 1 in 93% yield. Compound 2 was directly isolated as Boc-deprotected product, but in a much lower yield. We believe the lower yield is caused by the workup procedure, because TLC indicated nearly full consumption of 19. During column purification with aluminium oxide or silica (both

• were tried) we noticed smearing of the blue fluorescent product under UV irradiation. Even deactivated aluminium oxide provides enough acidity to split the Boc-moiety, which probably causes the generated amine to partly remain on the column. In the case of 6, using an excess of 19 lead to better yields

• are rounded to 0.1 Hz. Mass spectrometry: Thermofinnigan MAT95XL (EI). TLC: Silica plates (Polygram SIL G/UV 254), aluminium oxide plates (Polygram N/UV 254). Flash chromatography: Silica (Kieselgel 60, Fluka), aluminium oxide (aluminium oxide 90 neutral, Merck). Aluminium oxide, activity III, was

On the bromination of the dihydroazulene/vinylheptafulvene photo-/thermoswitch

• Virginia Mazzanti,
• Martina Cacciarini,
• Søren L. Broman,
• Christian R. Parker,
• Magnus Schau-Magnussen,
• Andrew D. Bond and
• Mogens B. Nielsen

Beilstein J. Org. Chem. 2012, 8, 958–966, doi:10.3762/bjoc.8.108

• ) with fluorescence indicator; color change of the spot from yellow (DHA) to red (VHF) upon irradiation by UV light indicated the presence of a DHA. For column chromatographic purification of DHAs, the column was covered by aluminium foil to exclude light; the isolated fractions were also kept in the

Low-generation dendrimers with a calixarene core and based on a chiral C₂-symmetric pyrrolidine as iminosugar mimics

• Marco Marradi,
• Stefano Cicchi,
• Francesco Sansone,
• Alessandro Casnati and
• Andrea Goti

Beilstein J. Org. Chem. 2012, 8, 951–957, doi:10.3762/bjoc.8.107

• , 80% overall yield). The amide coupling was then performed by reaction of 9 with pyrrolidine 4 using DIPEA as a base, and this afforded the branched tripyrrolidine 10 in 77% yield after column chromatography over neutral aluminium oxide. The tert-butoxycarbonyl group was then removed in the presence

Formation of carbohydrate-functionalised polystyrene and glass slides and their analysis by MALDI-TOF MS

• Martin J. Weissenborn,
• Johannes W. Wehner,
• Christopher J. Gray,
• Robert Šardzík,
• Claire E. Eyers,
• Thisbe K. Lindhorst and
• Sabine L. Flitsch

Beilstein J. Org. Chem. 2012, 8, 753–762, doi:10.3762/bjoc.8.86

• analysed directly on these minimally conducting surfaces by MALDI-TOF mass spectrometry analysis after aluminium tape was attached to the underside of the slides. Furthermore, the trityl group appeared to act as an internal matrix and no additional matrix was necessary for the MS analysis. Thus, trityl

• address these issues, we have investigated a simple and cheap method to enable MALDI-TOF MS analysis on minimally conductive supports by applying a commercially available aluminium tape to the underside of glass and polystyrene slides. This has allowed us to make standard microscope slides suitable for

• , successful MS analysis on such surfaces has not been reported. In order to circumvent this issue, commercially available aluminium tape was applied to the underside of a polystyrene microscope slide. The tape significantly enhanced both the signal intensity and resolution of MALDI-TOF MS analysis of the Man

Thiophene-based donor–acceptor co-oligomers by copper-catalyzed 1,3-dipolar cycloaddition

• Stefanie Potratz,
• Amaresh Mishra and
• Peter Bäuerle

Beilstein J. Org. Chem. 2012, 8, 683–692, doi:10.3762/bjoc.8.76

• chemicals were used as received without further purification unless otherwise specified. Thin-layer chromatography (TLC) was carried out on silica gel 60 F254 aluminium plates (Merck). Developed plates were dried and examined under a UV lamp. Preparative-column chromatography was carried out on glass

Sonogashira–Hagihara reactions of halogenated glycals

• Dennis C. Koester and
• Daniel B. Werz

Beilstein J. Org. Chem. 2012, 8, 675–682, doi:10.3762/bjoc.8.75

• SN2-type reaction takes place leading to the α-gluco-configured C-glycoside 15a in a moderate yield of 30% (Table 4). The aluminium centre coordinates the epoxide oxygen allowing the hydride to attack from the same side, leading to β-configured alkyl-C-glycosides. The epoxidation/ring-opening sequence

Facile synthesis of nitrophenyl 2-acetamido-2-deoxy-α-D-mannopyranosides from ManNAc-oxazoline

• Karel Křenek,
• Petr Šimon,
• Lenka Weignerová,
• Barbora Fliedrová,
• Marek Kuzma and
• Vladimír Křen

Beilstein J. Org. Chem. 2012, 8, 428–432, doi:10.3762/bjoc.8.48

• from Sigma-Aldrich, except for 2-acetamido-2-deoxy-D-mannose, which was purchased from BIOSYNTH AG, Staad, CH. The reactions were monitored by TLC with precoated silica gel 60 F254 aluminium sheets from Merck, detected with UV light and/or charred with sulfuric acid (5% in EtOH). The compounds were

Synthesis, solid-state fluorescence properties, and computational analysis of novel 2-aminobenzo[4,5]thieno[3,2-d]pyrimidine 5,5-dioxides

• Kenichirou Yokota,
• Masayori Hagimori,
• Naoko Mizuyama,
• Yasuhisa Nishimura,
• Hiroshi Fujito,
• Yasuhiro Shigemitsu and
• Yoshinori Tominaga

Beilstein J. Org. Chem. 2012, 8, 266–274, doi:10.3762/bjoc.8.28

• )aluminium (Alq3) was used as the standard for fluorescence spectrum measurements [17]. We analyzed the solid-state fluorescence emission spectra of 3a–g, 6 and 7 at room temperature. The fluorescence maxima (λem,max) and relative fluorescence intensities (RI) of these compounds are listed in Table 2. The