AuBr₃-catalyzed azidation of per-O-acetylated and per-O-benzoylated sugars

• Jayashree Rajput,
• Srinivas Hotha and
• Madhuri Vangala

Beilstein J. Org. Chem. 2018, 14, 682–687, doi:10.3762/bjoc.14.56

• and 100 MHz spectrometer, respectively using CDCl3 as the solvent. Chemical shifts (δ) are given in ppm. For perbenzoate compounds 10–15, tetramethyl silane was used as internal standard. Electrospray ionization (ESI) was used for high resolution mass spectrometry (HRMS). An FTIR spectrometer was used

Synthesis of a sucrose-based macrocycle with unsymmetrical monosaccharides "arms"

• Karolina Tiara,
• Mykhaylo A. Potopnyk and
• Sławomir Jarosz

Beilstein J. Org. Chem. 2018, 14, 634–641, doi:10.3762/bjoc.14.50

• -Ar), 119.07 (C-6), 115.51 (2 × C-Ar), 82.30 (C-3), 78.61 (C-2), 77.54 (C-4), 70.74 (C-1), 61.20 (OMe), 59.09 (OMe), 59.08 (OMe) ppm; HRMS (ESI) [M + Na]+: calcd for C15H21NO6Na, 334.1257; found, 334.1256; anal. calcd for C15H21NO6 (311.33): C, 57.87; H, 6.80; N, 4.50; found: C, 57.65; H, 6.79; N

• ), 3.49 (s, 3H, OMe), 3.43 (m, 4H, OMe, H-3), 3.34 (s, 3H, OMe) ppm; 13C NMR δ 163.82 (C-Ar), 141.61 (C-Ar), 135.54 (C-5), 125.89 (2 × C-Ar), 118.71 (C-6), 114.58 (2 × C-Ar), 82.59 (C-3), 81.81 (C-4), 78.81 (C-2), 67.56 (C-1), 61.25, 58.45, 56.72 (3 × OMe) ppm; HRMS (ESI) [M + Na]+: calcd for C15H21NO6Na

• -11), 70.37 (C-1’), 69.51 (C-5), 65.46 (C-6’), 61.10, 59.05, 59.05 (3 × OMe), 50.50 (C-6), 26.93 [3C, SiC(CH3)3], 22.90 (CH3CO2), 19.27 (Cquat-t-Bu) ppm; HRMS (ESI) [M + Na]+ calcd for C87H99O15SiNa, 1448.6669; found, 1448.6682; anal. calcd for C87H99NO15Si (1426.83): C, 73.24; H, 6.99; N, 0.98; found

An air-stable bisboron complex: a practical bidentate Lewis acid catalyst

• Longcheng Hong,
• Sebastian Ahles,
• Andreas H. Heindl,
• Gastelle Tiétcha,
• Andrey Petrov,
• Zhenpin Lu,
• Christian Logemann and
• Hermann A. Wegner

Beilstein J. Org. Chem. 2018, 14, 618–625, doi:10.3762/bjoc.14.48

• ), 7.69 (br s, 2H), 7.28 (dd, 3J = 5.2 Hz, 3.2 Hz, 4H), 6.71 (dd, 3J = 5.2 Hz, 3.2 Hz, 4H), 0.95 (s, 6H); 13C NMR (100 MHz, THF-d8) δ 147.2, 133.7, 128.1, 124.2 (C atoms next to boron are not observable due to quadrupole coupling); 11B NMR (128 MHz, THF-d8) δ 2.4 (s)M; mp 252–253 °C; HRMS–ESI (m/z): [M

Synthesis of fluoro-functionalized diaryl-λ³-iodonium salts and their cytotoxicity against human lymphoma U937 cells

• Prajwalita Das,
• Etsuko Tokunaga,
• Hidehiko Akiyama,
• Hiroki Doi,
• Norimichi Saito and
• Norio Shibata

Beilstein J. Org. Chem. 2018, 14, 364–372, doi:10.3762/bjoc.14.24

• white solid (430 mg) in 72% yield. mp: 163.7–164.7 °C; HRMS (ESI–TOF) m/z [M − OTf]+: calcd for C15H15F5SI, 448.9859; found, 448.9865; 1H NMR ((CD3)2CO), 300 MHz) δ 2.44 (s, 3H), 2.69 (s, 6H), 7.42 (s, 2H), 7.64 (d, J = 6 Hz, 1H), 7.73 (t, J = 9 Hz, 1H), 7.96 (t, J = 9 Hz, 1H), 8.36 (dd, J = 9 Hz, 1.5

• as a white solid (604 mg) in 86% yield. mp: 106.6–107.9 °C; HRMS (ESI–TOF) m/z [M − OTf]+: calcd for C21H27F5SI, 533.0798; found, 533.0798; 1H NMR ((CD3)2CO, 300 MHz) δ 1.31 (t, J = 9 Hz, 18H), 3.14 (q, J = 9 Hz, 1H), 3.30 (q, J = 6 Hz, 2H), 7.45 (d, J = 9 Hz, 1H), 7.58 (s, 2H), 7.77 (t, J = 6 Hz, 1H

• room temperature for 18 h to give 5a as a white solid (600 mg) in 81% yield. mp: 108.7–110.4 °C; HRMS (ESI–TOF) m/z [M − OTf]+: calcd for C13H11OF5SI, 436.9495; found, 436.9499; 1H NMR ((CD3)2CO, 300 MHz) δ 3.90 (s, 3H), 7.16 (d, J = 9 Hz, 2H), 7.86 (t, J = 9 Hz, 1H), 8.03 (t, J = 9 Hz, 1H), 8.29 (d, J

Transition-metal-free [3 + 3] annulation of indol-2-ylmethyl carbanions to nitroarenes. A novel synthesis of indolo[3,2-b]quinolines (quindolines)

• Michał Nowacki and
• Krzysztof Wojciechowski

Beilstein J. Org. Chem. 2018, 14, 194–202, doi:10.3762/bjoc.14.14

• expressed in parts per million (ppm) referred to TMS, coupling constants in hertz (Hz). Electron impact mass spectra (EI, 70 eV) were obtained on an AutoSpec Premier spectrometer. Electrospray mass spectra (ESI) were obtained on 4000 Q-TRAP and SYNAPT G2-S HDMS. Silica gel (Merck 60, 230–400 mesh) was used

• , 117.53, 121.99, 123.55, 124.35, 124.38, 127.16, 128.99, 131.53, 140.73, 142.28, 143.37, 149.70, 150.50, 154.09, 163.93. HRMS (ESI) m/z: calcd for C24H26N3O4+, 420.1923.; found, 420.1917. Selected indolo[3,2-b]quinolines (quindolines) with biological activity. Selected starting materials for the

From dipivaloylketene to tetraoxaadamantanes

• Gert Kollenz and
• Curt Wentrup

Beilstein J. Org. Chem. 2018, 14, 1–10, doi:10.3762/bjoc.14.1

• derivatives were prepared from 3 in order to examine their host–guest properties by ESI mass spectrometry and NMR spectroscopy. Some tetraoxaadamantanes were also examined in this way. For example, compound 30 (Figure 1) was found to have a particular affinity for complexation with choline [26][36], and the

Position-dependent impact of hexafluoroleucine and trifluoroisoleucine on protease digestion

• Susanne Huhmann,
• Anne-Katrin Stegemann,
• Kristin Folmert,
• Damian Klemczak,
• Johann Moschner,
• Michelle Kube and
• Beate Koksch

Beilstein J. Org. Chem. 2017, 13, 2869–2882, doi:10.3762/bjoc.13.279

• of substrate degradation, integration of the corresponding HPLC peak was conducted. Cleavage products were identified by ESI–ToF mass spectrometry (see Supporting Information File 1, Tables S4–S7). Figure S2 (Supporting Information File 1) shows the time course of all of the digestion experiments. A

• . Full length P2’-HfLeuFA and P2’-TfIleFA are present at percentages up to 44% and 24%, respectively, while substitution by Leu and Ile in P2’ position leads to accelerated proteolysis compared to FA. Thus, both HfLeu and TfIle have a protective effect towards proteolysis in this position. ESI–ToF mass

• -terminal to uncharged non-aromatic amino acids and mainly between Ala–Ala and Ala–Gly bonds [56][73]. Since Ala is the main residue present in the peptides studied here, we observed various cleavage products in the ESI–ToF analysis (Figure 7, see Supporting Information File 1, Table S6). For none of the

Reagent-controlled regiodivergent intermolecular cyclization of 2-aminobenzothiazoles with β-ketoesters and β-ketoamides

• Irwan Iskandar Roslan,
• Kian-Hong Ng,
• Gaik-Khuan Chuah and
• Stephan Jaenicke

Beilstein J. Org. Chem. 2017, 13, 2739–2750, doi:10.3762/bjoc.13.270

• , 125.0, 123.6, 118.3, 117.6, 51.6, 16.9; HRMS–ESI (m/z): [M + H]+: calcd for C12H11N2O2S, 247.0536; found, 247.0533. Representative procedure for the synthesis of benzo[d]imidazo[2,1-b]thiazole: A 10 mL round-bottomed flask was charged with 2-aminobenzothiazole (1a, 150 mg, 1.0 mmol), methyl acetoacetate

• , 95%); mp 202–204 °C; 1H NMR (300 MHz, CDCl3) δ 8.94 (d, J = 7.5 Hz, 1H), 7.57 (d, J = 7.2 Hz, 1H), 7.44–7.33 (m, 2H), 6.16 (s, 1H), 2.30 (s, 3H); 13C NMR (75 MHz, CDCl3) δ 162.6, 161.1, 160.8, 135.8, 126.7, 126.6, 123.8, 121.5, 119.7, 106.9, 23.5; HRMS–ESI (m/z): [M + H]+ calcd for C11H9N2OS

An efficient synthesis of 1,6-anhydro-N-acetylmuramic acid from N-acetylglucosamine

• Matthew B. Calvert,
• Christoph Mayer and
• Alexander Titz

Beilstein J. Org. Chem. 2017, 13, 2631–2636, doi:10.3762/bjoc.13.261

• ); HRMS (ESI–TOF) m/z: [M + H]+ calcd for C30H32NO7, 518.21788; found, 518.21596. 1,6-Anhydro-N-acetylmuramic acid (1) A solution of 13 (720 mg, 1.4 mmol) in chloroform (20 mL) was treated with trifluoroacetic acid (1.0 mL) at 0 °C. The reaction mixture was allowed to warm to room temperature, stirred

• data in agreement with literature values [8]. HRMS (ESI–TOF) m/z: [M + H]+ calcd for C11H18NO7, 276.10833; found, 276.10892. 4-O-Triphenylmethyl-1,6-anhydro-N-acetylmuramic acid (13) and 4-O-triphenylmethyl-1,6-anhydro-N-acetylisomuramic acid (14) A solution of 12 (224 mg, 0.5 mmol) in dioxane (2.5 mL

• ), 170.91 (C=O, Ac), 101.81 (CH, C-1), 80.20 (CH, C-3), 77.16 (CH, C-5), 74.58 (CH, α-Lac), 70.94 (CH, C-4), 65.97 (CH2, C-6), 50.97 (CH, C-2), 23.05 (Me, Ac), 19.23 (Me, Lac-Me); HRMS (ESI–TOF) m/z: [M + H]+ calcd for C11H18NO7, 276.10833; found, 276.10713. AnhydroMurNAc and derivatives. 2D NMR

Synthesis of 1,3-cis-disubstituted sterically encumbered imidazolidinone organocatalysts

• Jan Wallbaum and
• Daniel B. Werz

Beilstein J. Org. Chem. 2017, 13, 2577–2583, doi:10.3762/bjoc.13.254

• were made by combination of H,H-COSY, HSQC, HMBC and NOESY experiments. In some cases signals in the 13C NMR spectrum are missing because of bad relaxation of the respective signals. ESI high-resolution mass spectrometry was carried out on a FTICR instrument. IR spectra were measured on an ATR

• , 122.7, 125.1, 125.1, 126.0, 126.6, 126.7, 128.8, 137.2, 137.3, 137.8 (the carbonyl signal as well as one aliphatic, one aromatic CH and one aromatic Cq-signal are missing); (c 1.0, CHCl3) +38.0°; IR (ATR) (cm−1): 3349, 2922, 1683, 1261, 1159; HRMS (ESI) m/z: calcd for C19H20N4O, 343.1529; found

• , 180.3 (one aliphatic CH and one aromatic CH are missing); (c 1.0, CHCl3) −6.0°; IR (ATR) (cm−1): 3404, 3280, 1681, 1435, 1097; HRMS (ESI) m/z: calcd for C23H21N3O, 378.1577; found, 378.1578. (2S,5S)-5-((N-Benzylindol-3-yl)methyl)-3-methyl-2-(naphthalen1-yl)imidazolidin-4-one (7d). (S)-N

A novel synthetic approach to hydroimidazo[1,5-b]pyridazines by the recyclization of itaconimides and HPLC–HRMS monitoring of the reaction pathway

• Dmitry Yu. Vandyshev,
• Khidmet S. Shikhaliev,
• Andrey Yu. Potapov,
• Michael Yu. Krysin,
• Fedor I. Zubkov and
• Lyudmila V. Sapronova

Beilstein J. Org. Chem. 2017, 13, 2561–2568, doi:10.3762/bjoc.13.252

• probable routes of the cascade recyclization process, because ions of the protonable substances are only fixed in the given ESI–MS conditions, and precipitation of the product is observed as the reaction proceeds. The latter causes a decreased content of the imidazopyridazine 9d in the liquid phase is

• observed, whose peak is identified by the retention time (4.13 min) determined for the pure substance. The long retention time (5.6 min) and the insignificant content (less than 1%) of the initial itaconimide 1d found under ESI conditions in the reaction mixture are due to its extremely low proton affinity

A concise flow synthesis of indole-3-carboxylic ester and its derivatisation to an auxin mimic

• Marcus Baumann,
• Ian R. Baxendale and
• Fabien Deplante

Beilstein J. Org. Chem. 2017, 13, 2549–2560, doi:10.3762/bjoc.13.251

• ), 1324 (s), 1257 (s), 1182 (s), 1138 (s), 1090 (s), 1012 (m), 866 (m), 825 (m), 698 (m); LC–MS (TOF+) 302.1 (M + H); HRMS (ESI) m/z: calcd for C12H8N2O4F3, 301.0436; found, 301.0452 (Δ = 5.3 ppm); melting range: 60.5–61.6 °C; X-ray crystal data: CCDC 1572810. Ethyl 6-(trifluoromethyl)-1H-indole-3

• ), 1328 (s), 1228 (s), 1191 (m), 1160 (s), 1117 (s), 1055 (s), 826 (m), 745 (m), 674 (m), 615 (m), 524 (m); LC–MS (TOF+) 258.1 (M + H); HRMS (ESI) m/z: calcd for C12H11NO2F3, 258.0742; found, 258.0753 (Δ = 4.3 ppm); melting range: 197.3–200.0 °C; X-ray crystal data: CCDC 1572811. Ethyl 2-amino-6

• ), 1070 (s), 1052 (s), 856 (m), 812 (s), 671 (m), 530 (m); LC–MS (TOF+) 273.1 (M + H); HRMS (ESI) m/z: calcd for C12H12N2O2F3, 273.0851; found, 273.0860 (Δ = 3.3 ppm); melting range: >140 °C (decomposition); X-ray crystal data: CCDC 1572812. Ethyl 2-amino-1-hydroxy-6-(trifluoromethyl)-1H-indole-3

Pyrene–nucleobase conjugates: synthesis, oligonucleotide binding and confocal bioimaging studies

• Artur Jabłoński,
• Yannic Fritz,
• Hans-Achim Wagenknecht,
• Rafał Czerwieniec,
• Tytus Bernaś,
• Damian Trzybiński,
• Krzysztof Woźniak and
• Konrad Kowalski

Beilstein J. Org. Chem. 2017, 13, 2521–2534, doi:10.3762/bjoc.13.249

• residual DMSO (1H δ 2.50 ppm, 13C δ 39.70) or CHCl3 (1H δ 7.26 ppm, 13C δ 77.00) as reference. Infrared spectra were recorded with a FTIR Nexus Nicolet apparatus. Mass spectra were recorded with a Varian 500-MS iT mass spectrometer (ESI) or with a Finnigan Mat95 mass spectrometer (EI). Microanalyses were

A permutation approach to the assignment of the configuration to diastereomeric tetrads by comparison of experimental and ab initio calculated differences in NMR data

• Przemysław J. Boratyński

Beilstein J. Org. Chem. 2017, 13, 2478–2485, doi:10.3762/bjoc.13.245

• , 128.00, 122.5, 119.9, 115.0, 100.7, 59.2 (br.), 58.4, 55.8, 49.4, 47.6, 39.2, 27.8, 26.5, 26.0, −1.0 ppm. HRMS–ESI–TOF (m/z): [M + H]+ calcd for C25H34N5OSi, 448.2527; found, 448.2521. 9S- and 9R-(1,2,3-triazol-1-yl)-9-deoxyquinidine (1d and 1c): 9R-(4-Trimethylsilyl-1,2,3-triazol-1-yl)-9-deoxyquinidine

• (329 mg, 0.77 mmol) was dissolved in THF (10 mL), then a solution of TBAF (1.1 mL, 1 M in THF, 1.4 equiv) was added, and the mixture was stirred at 60 °C for 28 h and evaporated. HRMS–ESI–TOF (m/z): [M + H]+ calcd for C22H24N5O, 376.2132; found, 376.2126. Chromatography on silica gel (CHCl3/MeOH, 20:1

• , 132.1, 128.0, 122.25, 122.20, 119.9, 114.9, 100.4, 61.4, 57.4, 56.0, 55.8, 41.5, 39.5, 27.7, 27.2, 25.2 ppm; HRMS–ESI–TOF (m/z): [M + H]+ calcd for C22H26N5O, 376.2132; found, 376.2141. 9R-Phenyl-9-deoxyquinine (2b): Under inert gas (Ar), a sodium hydride dispersion (60% in mineral oil, 195 mg, 4.9 mmol

Hydrolysis, polarity, and conformational impact of C-terminal partially fluorinated ethyl esters in peptide models

• Vladimir Kubyshkin and
• Nediljko Budisa

Beilstein J. Org. Chem. 2017, 13, 2442–2457, doi:10.3762/bjoc.13.241

• , δ-CH2), 29.2 (s, β-CH2), 24.2 (s, γ-CH2), 21.2 (s, CH3); s-cis, 174.6 (s, CO2), 173.4 (s, N-C=O), 60.7 (s, α-CH), 53.2 (s, OCH3), 46.6 (s, δ-CH2), 30.6 (s, β-CH2), 22.3 (s, γ-CH2), 21.2 (s, CH3); HRMS (ESI-orbitrap): [M + H]+ calcd for C8H14NO3, 172.0968; found, 172.0968; [α]D25 −83 (c 2.0, CHCl3

• -CH2), 29.3 (s, β-CH2), 24.3 (s, γ-CH2), 21.2 (s, CH3), 13.2 (s, CH3); s-cis, 174.2 (s, CO2), 173.3 (s, N-C=O), 63.0 (s, OCH2), 60.8 (s, α-CH), 46.7 (s, δ-CH2), 30.7 (s, β-CH2), 22.3 (s, γ-CH2), 21.2 (s, CH3), 13.2 (s, CH3); HRMS (ESI-orbitrap): [M + H]+ calcd for C9H16NO3, 186.1125; found, 186.1120

• ), 30.6 (s, β-CH2), 22.3 (s, γ-CH2), 21.2 (s, CH3); 19F NMR (D2O, 471 MHz) δ −224.3 (tt, JFH = 47, 30 Hz, s-trans), −224.6 (tt, J = 47, 30 Hz, s-cis); HRMS (ESI-orbitrap): [M + H]+ calcd for C9H15FNO3, 204.1030; found, 204.1028; [α]D25 −45 (c 2.0, CHCl3), er 74:26. 2,2-Difluoroethyl N-acetylprolinate (4

Structural diversity in the host–guest complexes of the antifolate pemetrexed with native cyclodextrins: gas phase, solution and solid state studies

• Magdalena Ceborska,
• Magdalena Zimnicka,
• Aneta Aniela Kowalska,
• Kajetan Dąbrowa and
• Barbara Repeć

Beilstein J. Org. Chem. 2017, 13, 2252–2263, doi:10.3762/bjoc.13.222

• order of stability to be obtained [16]. Similarly to the CDs/FA complexes, PTX with α-CD, β-CD, and γ-CD forms stable noncovalent associates (1:1 host–guest) in the gas phase, which are detected as doubly negatively charged ions ([CD + PTX − 2H]2−) in the negative-ESI mass spectra (see Supporting

• electrospray ion source operated in the standard negative ESI mode, i.e., without additional drying gas. The three solutions containing PTX sodium salt (0.04 mM) and α-CD, β-CD, and γ-CD (0.04 mM) were prepared in water/methanol (1:1 v/v). Analyte solutions were introduced into the ion source with a syringing

An efficient synthesis of a C₁₂-higher sugar aminoalditol

• Łukasz Szyszka,
• Anna Osuch-Kwiatkowska,
• Mykhaylo A. Potopnyk and
• Sławomir Jarosz

Beilstein J. Org. Chem. 2017, 13, 2146–2152, doi:10.3762/bjoc.13.213

• (C-2), 79.71 (C-10), 79.18 (C-11), 78.55 (C-4), 78.45 (C-6), 77.54 (C-7), 77.34 (C-8), 77.11 (C-9), 75.39, 74.65, 74.36, 73.33, 73.29, 73.01, 72.38, 72.08, 71.73 (9 × OCH2Ph), 69.64 (C-5), 55.01 (OCH3), 51.83 (C-12) ppm; HRMS (ESI) m/z: [M + Na]+ calcd for C76H79N3O11Na, 1232.5590; found, 1232.5612

• (C-6), 82.26 (C-3), 79.62 (C-10), 79.06 (C-2), 78.90 (C-11), 77.79 (C-4), 77.63, 77.39, 77.34 (C-7, C-8, C-9), 75.32, 74.70, 74.54, 73.16, 73.10, 72.84, 72.61, 72.22, 72.14 (9 × OCH2Ph), 72.61 (C-5), 51.78 (C-12), 20.94 (CH3) ppm; HRMS (ESI) m/z: [M + Na]+ calcd for C77H79N3O12Na: 1260.5537; found

• –3.26 (m, 2H, H-1’, H-12’) ppm; 13C NMR (150 MHz) δ 128.42–127.25 (m, 45 × C-Ph), 79.78, 79.74, 79.35, 79.15, 79.12, 78.87, 78.68, 77.76, 77.67, 74.69, 74.03, 73.74, 73.47, 73.16, 72.82, 72.73, 72.04, 72.04 (9 × OCH2Ph), 70.74 (C-5), 61.60 (C-1), 51.88 (C-12) ppm; HRMS (ESI) m/z: [M + Na]+ calcd for

Preparation of imidazo[1,2-a]-N-heterocyclic derivatives with gem-difluorinated side chains

• Layal Hariss,
• Kamal Bou Hadir,
• Mirvat El-Masri,
• Thierry Roisnel,
• René Grée and
• Ali Hachem

Beilstein J. Org. Chem. 2017, 13, 2115–2121, doi:10.3762/bjoc.13.208

• , 4J = 1.1 Hz), 128.8, 128.7 (2C), 128.5 (2C), 128.3 (2C), 126.5, 126.3, 125.9, 114.1 (t, 1J = 233.4 Hz), 87.0 (t, 3J = 6.8 Hz), 79.1 (t, 2J = 40.9 Hz), 64.0 (t, 4J = 1.8 Hz), 40.8 (t, 2J = 26.1 Hz), 28.9 (t, 3J = 4.0 Hz); 19F NMR (CDCl3, 282 MHz) δ −83.45 (td, JFH = 14.6, 3.9 Hz); HRMS (ESI) m/z [M

• = 240.4 Hz), 38.9 (t, 2J = 25.9 Hz), 28.2 (t, 3J = 4.3 Hz); 19F NMR (CDCl3, 282 MHz) δ −98.84 (m); HRMS (ESI) m/z [M + Na]+: calcd. for C18H16OF2Na, 309.10614; found, 309.1059 (1 ppm). Synthesis of (2-(1,1-difluoro-3-phenylpropyl)imidazo[1,2-a]pyridin-3-yl)(phenyl)methanone (7a) A mixture of 2

• ); HRMS (ESI) m/z [M + Na]+: calcd. for C23H18N2OF2Na, 399.12794; found, 399.1279 (0 ppm); m/z [M + H]+: calcd. for C23H19N2OF2, 377.14599; found, 377.1454 (2 ppm); m/z [M – HF + Na]+: calcd. for C23H17N2OFNa, 379.12171; found, 379.1216 (0 ppm). One pot synthesis of (2-(1,1-difluoro-3-phenylpropyl)imidazo

Enzymatic separation of epimeric 4-C-hydroxymethylated furanosugars: Synthesis of bicyclic nucleosides

• Neha Rana,
• Manish Kumar,
• Vinod Khatri,
• Jyotirmoy Maity and
• Ashok K. Prasad

Beilstein J. Org. Chem. 2017, 13, 2078–2086, doi:10.3762/bjoc.13.205

• recorded on a JEOL Alpha-400 spectrometer at 400 and 100.6 MHz, respectively, using TMS as internal standard. The chemical shift values are on δ scale and the coupling constants (J) are in Hz. The HRMS analysis was done on a Q-TOF mass spectrometer using ESI positive mode. The optical rotations were

• , 62.25, 26.45, 26.22, 20.85; HR-ESI-TOF-MS m/z: [M + Na]+ calcd. for [C11H18O7Na]+ 285.0945, found: 285.0947, 5-O-Acetyl-4-C-hydroxymethyl-1,2-O-isopropylidene-α-D-xylofuranose (4b). It was obtained as colourless oil (1.10 g, 46% yield). Rf = 0.3 (5.0% methanol in chloroform); [α]D22 −13.85 (c 0.1, MeOH

• , 100.6 MHz) δ 170.76, 113.56, 104.64, 86.87, 79.44, 72.84, 65.70, 62.23, 26.43, 26.20, 20.84; HR-ESI-TOF-MS m/z: [M + H]+ calcd. for [C11H19O7]+ 263.1125, found 263.1130. General procedure for the tosylation of monoacetylated sugar derivatives 4a and 4b: synthesis of compounds 5 and 10. Similar as

A novel application of 2-silylated 1,3-dithiolanes for the synthesis of aryl/hetaryl-substituted ethenes and dibenzofulvenes

• Grzegorz Mlostoń,
• Paulina Pipiak,
• Róża Hamera-Fałdyga and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2017, 13, 1900–1906, doi:10.3762/bjoc.13.185

• , CDCl3) δ 119.3, 124.8, 126.6, 127.4, 128.1, 128.5, 129.2 (14 CHarom), 137.7, 138.4, 140.6, 144.6 (6 Carom, 2 C=) ppm; HRMS–ESI+ (TOF): [M]+ calcd for C22H14S2, 342.0537; found, 342.0527. Preparation of 1,3-dithiolanes 13a,b: Both compounds were prepared from commercial methyl (trimethylsilyl) ketone or

Pd(OAc)₂/Ph₃P-catalyzed dimerization of isoprene and synthesis of monoterpenic heterocycles

• Dominik Kellner,
• Maximilian Weger,
• Andrea Gini and
• Olga García Mancheño

Beilstein J. Org. Chem. 2017, 13, 1807–1815, doi:10.3762/bjoc.13.175

• ), 34.1 (C-7), 32.7 (C-8), 22.4 (Me-6), 21.4 (Me-16), 13.8 (Me-10); HRMS (ESI+): calcd. for [C17H24NO2S]+: 306.1528; found: 306.1529. Isoprene as chemical building block in nature and organic synthesis. Pd-catalyzed dimerization of isoprene. Putative mechanism for the Pd(OAc)2-catalyzed dimerization of

An efficient Pd–NHC catalyst system in situ generated from Na₂PdCl₄ and PEG-functionalized imidazolium salts for Mizoroki–Heck reactions in water

• Nan Sun,
• Meng Chen,
• Liqun Jin,
• Wei Zhao,
• Baoxiang Hu,
• Zhenlu Shen and
• Xinquan Hu

Beilstein J. Org. Chem. 2017, 13, 1735–1744, doi:10.3762/bjoc.13.168

• standard. Mass spectrometry data (MALDI–TOF) of the three imidazolium salts L1–L3 were collected on a Bruker ultrafleXtreme mass spectrometer. Low-resolution mass analyses were performed on a Thermo Trace ISQ GC–MS instrument in EI mode (70 eV) or a Thermo Scientific ITQ 1100TM mass spectrometer in ESI

1-Imidoalkylphosphonium salts with modulated C_α–P⁺ bond strength: synthesis and application as new active α-imidoalkylating agents

• Jakub Adamek,
• Roman Mazurkiewicz,
• Anna Węgrzyk and
• Karol Erfurt

Beilstein J. Org. Chem. 2017, 13, 1446–1455, doi:10.3762/bjoc.13.142

• , respectively, as zero ppm. All chemical shifts (δ) are reported in ppm, and coupling constants (J) are given in hertz (Hz). High-resolution mass spectrometry (HRMS) analyses were performed on a Waters Xevo G2 Q-TOF mass spectrometer equipped with an ESI source operating in the positive ion mode. The accurate

A speedy route to sterically encumbered, benzene-fused derivatives of privileged, naturally occurring hexahydropyrrolo[1,2-b]isoquinoline

• Olga Bakulina,
• Alexander Ivanov,
• Vitalii Suslonov,
• Dmitry Dar’in and
• Mikhail Krasavin

Beilstein J. Org. Chem. 2017, 13, 1413–1424, doi:10.3762/bjoc.13.138

• HRMS-ESI-qTOF spectrometer (electrospray ionization mode). X-ray single crystal analyses were performed with monochromated Mo Kα or Cu Kα radiation, respectively. Column chromatography was performed on silica gel 60 (230–400 mesh). For TLC analysis UV254 silica gel coated plates were used. MeCN was

An improved preparation of phorbol from croton oil

• Alberto Pagani,
• Simone Gaeta,
• Andrei I. Savchenko,
• Craig M. Williams and
• Giovanni Appendino

Beilstein J. Org. Chem. 2017, 13, 1361–1367, doi:10.3762/bjoc.13.133

• of a colorless powder. The major diterpene polyols from croton oil [phorbol (1a), 4α-phorbol (2), 4-deoxy-4α-phorbol (3a)] and their derivatives. Supporting Information Supporting Information File 168: ESI-HRMS and 1H and 13C NMR spectra of compounds 1d and 1e. Acknowledgements We acknowledge