Formation of an unexpected 3,3-diphenyl-3H-indazole through a facile intramolecular [2 + 3] cycloaddition of the diazo intermediate

• Andrew T. King,
• Hugh G. Hiscocks,
• Lidia Matesic,
• Mohan Bhadbhade,
• Roger Bishop and
• Alison T. Ung

Beilstein J. Org. Chem. 2019, 15, 1347–1354, doi:10.3762/bjoc.15.134

• presence of benzyltriethylammonium chloride (BTEAC) and CuCl2 gave a crude product which was purified by crystallisation from dichloromethane/hexane to give a pale yellow crystalline material in 27% yield. HRMS–ESI analysis produced [M + H]+ m/z 467.2126 corresponding to the formula of C33H27N2O

• Spectrometer (ESI). The infrared spectra were recorded on an Agilent Cary 630 FTIR with a diamond window using 16 background and sample scans. Melting points were measured on a Gallenkamp Melting Point Apparatus equipment and were uncorrected. Synthesis of 7-benzhydryl-5-methoxy-3,3-diphenyl-3H-indazole (8

• ), 126.6 (2CH), 115.9 (CH), 107.7 (CH), 101.5 (C(Ph)2), 55.8 (CH3), 51.3 (HC(Ph)2); HRMS–ESI (m/z): [M + H]+ calcd for C33H27N2O, 467.2118; found, 467.2126. Direct preparation of compound 8 - method a Under a nitrogen atmosphere, compound 5 (0.23 g, 0.505 mmol, 1 equiv) was dissolved in acetonitrile (20 mL

Bambusuril analogs based on alternating glycoluril and xylylene units

• Tomáš Lízal and
• Vladimír Šindelář

Beilstein J. Org. Chem. 2019, 15, 1268–1274, doi:10.3762/bjoc.15.124

• ESI/APCI as an ion source and a manual pump for sampling. Matrix-assisted laser desorption ionization–time-of-flight mass spectra (MALDI–TOF MS) were measured on a MALDI–TOF MS UltrafleXtreme (Bruker Daltonics) and samples were ionized with the aid of a Nd:YAG laser (355 nm) from α-cyano-4

Self-assembly behaviors of perylene- and naphthalene-crown macrocycle conjugates in aqueous medium

• Xin Shen,
• Bo Li,
• Tiezheng Pan,
• Jianfeng Wu,
• Yangxin Wang,
• Jie Shang,
• Yan Ge,
• Lin Jin and
• Zhenhui Qi

Beilstein J. Org. Chem. 2019, 15, 1203–1209, doi:10.3762/bjoc.15.117

• final compounds were carefully characterized by 1H and 13C NMR spectroscopy and electrospray ionization mass spectroscopy (ESI-MS, Supporting Information File 1, Figures S1–S8). UV–vis absorption and fluorescence spectra of 1 in different solvents, including CHCl3, MeCN, MeOH, H2O, and mixed solvent

Unexpected polymorphism during a catalyzed mechanochemical Knoevenagel condensation

• Sebastian Haferkamp,
• Andrea Paul,
• Adam A. L. Michalchuk and
• Franziska Emmerling

Beilstein J. Org. Chem. 2019, 15, 1141–1148, doi:10.3762/bjoc.15.110

• spectra were recorded with electrospray ionization time of flight mass spectrometry. A Q-TOF Ultima ESI-TOF mass spectrometer (Micromass, Germany) running at 4 kV capillary voltage and a cone voltage of 35 V was used. The collision energy was set to 5 eV. The source temperature was 120 °C whereas the

Diaminoterephthalate–α-lipoic acid conjugates with fluorinated residues

• Leon Buschbeck,
• Aleksandra Markovic,
• Gunther Wittstock and
• Jens Christoffers

Beilstein J. Org. Chem. 2019, 15, 981–991, doi:10.3762/bjoc.15.96

• spectra were recorded on a Bruker Avance DRX 500 instrument. Multiplicities of carbon signals were determined with DEPT experiments. HRMS spectra of products were obtained with Waters Q-TOF Premier (ESI) or Thermo Scientific DFS (EI) spectrometers. IR spectra were recorded on a Bruker Tensor 27

• ; HRMS (ESI, pos. mode): [M + H+] calcd for C31H41F3N3O5S2+, 656.2434; found, 656.2440; UV–vis (CH2Cl2): λmax (lg ε) = 514 nm (3.58); fluorescence (CH2Cl2): λem = 514 nm, λex = 566 nm, Φ = 0.04; C31H40F3N3O5S2 (655.79 g·mol−1). Preparation of SAMs of compounds 3 and 7: Gold surfaces were prepared onto

Efficient synthesis of pyrazolopyridines containing a chromane backbone through domino reaction

• Razieh Navari,
• Saeed Balalaie,
• Saber Mehrparvar,
• Fatemeh Darvish,
• Frank Rominger,
• Fatima Hamdan and
• Sattar Mirzaie

Beilstein J. Org. Chem. 2019, 15, 874–880, doi:10.3762/bjoc.15.85

• -resolution mass spectra and were recorded on Mass-ESI-POS(FT-ICR-Qe) spectrometer. General procedure for the synthesis of compounds 1a–g In a 25 mL flask containing 3 mL ethanol, 3-formylchromone derivatives (1 mmol) and hydrazine derivatives (1 mmol) were added and the mixture stirred for three hours at

Photochemical generation of the 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) radical from caged nitroxides by near-infrared two-photon irradiation and its cytocidal effect on lung cancer cells

• Ayato Yamada,
• Manabu Abe,
• Yoshinobu Nishimura,
• Shoji Ishizaka,
• Masashi Namba,
• Taku Nakashima,
• Kiyofumi Shimoji and
• Noboru Hattori

Beilstein J. Org. Chem. 2019, 15, 863–873, doi:10.3762/bjoc.15.84

• ), 126.43 (C), 125.01 (CH), 124.33 (CH), 124.07 (CH), 121.22 (CH), 110.42 (CH), 105.12 (CH), 29.25 (CH2), 15.84 (CH3); HRMS–ESI (m/z): [M−] calcd. for C16H13NO3, 267.09009; found, 267.09064. 2,2,6,6-Tetramethyl-1-(1-(2-(4-nitrophenyl)benzofuran-6-yl)ethoxy)piperidine (2a). Under air, TEMPO (0.23 g, 1.5 mmol

• ), 109.47 (CH), 105.13 (CH), 83.28 (CH), 59.79 (C), 40.43 (CH2), 34.23 (CH3) , 23.82 (CH2), 20.40 (CH3), 17.24 (CH3); HRMS–ESI (m/z): [M + H]+ calcd. for C25H30N2O4, 423.22783; found, 423.22754. 5-Ethyl-2-(4-nitrophenyl)benzofuran (5b). 4-Nitro-1-iodobenzene (16.8 g, 67.5 mmol), Pd(dppf)Cl2 (1.0 g, 1.3 mmol

• ); 13C NMR (100 MHz, CDCl3) δ (ppm) 154.12 (C), 153.38 (C), 147.21 (C), 139.74 (C), 136.47 (C), 128.79 (C), 126.24 (CH), 125.12 (CH), 124.29 (CH), 120.14 (CH), 111.12 (CH), 105.04 (CH), 28.83 (CH2), 16.15 (CH3); HRMS–ESI (m/z): [M−] calcd. for C16H13NO3, 267.09009; found, 267.09030. 2,2,6,6-Tetramethyl-1

Strong hyperconjugative interactions limit solvent and substituent influence on conformational equilibrium: the case of cis-2-halocyclohexylamines

• Camila B. Francisco,
• Cleverton S. Fernandes,
• Ulisses Z. de Melo,
• Roberto Rittner,
• Gisele F. Gauze and
• Ernani A. Basso

Beilstein J. Org. Chem. 2019, 15, 818–829, doi:10.3762/bjoc.15.79

• ), 52.80 (C1), 30.84 (C3, C6), 20.85 (C4), 24.88 (C5); HRMS (ESI/QTOF) m/z: [M + H]+ calcd for C6H12FN, 118.0953; found, 118.0991. cis-2-Chlorocyclohexylamine: 1H NMR (500.13 MHz, dichloromethane-d2) δ 4.30 (ddd, 1H, H2), 2.80 (ddd, 1H, H1), 2.04 (m, 1H, 1H3), 1.78 (m, 1H, 1H3), 1.70–1.60 (m, 2H, 1H5, 1H4

• ), 1,54 (m, 2H, 2H6), 1.40 (m, 1H, 1H4), 1.30 (m, 1H, 1H5); 13C NMR (125.77 MHz, dichlorotmethane-d2) δ 68.47 (C2), 53.22 (C1), 33.16 (C3), 31.30 (C6), 23.76 (C5), 21.10 (C4); HRMS (ESI/QTOF) m/z: [M + H]+ calcd for C6H12ClN, 134.0658; found, 134.0692. cis-2-Bromocyclohexylamine: 1H NMR (500.13 MHz

• , dichloromethane-d2) δ 4.68 (ddd, 1H, H2), 2.97 (ddd, 1H, H1), 2.18 (m, 1H, H3), 1.93 (m, 1H, H3), 1.77–1.63 (m, 4H, 1H4, 1H5, 2H6), 1.50 (m, 1H, H4), 1.37 (m, 1H, H5); 13C NMR (125.77 MHz, dichlorotmethane-d2) δ 62.19 (C1), 53.42 (C2), 33.67 (C3), 30.08 (C5), 23.87 (C6), 21.28 (C4); HRMS (ESI/QTOF) m/z: [M + H

Polyaminoazide mixtures for the synthesis of pH-responsive calixarene nanosponges

• Antonella Di Vincenzo,
• Antonio Palumbo Piccionello,
• Alberto Spinella,
• Delia Chillura Martino,
• Marco Russo and
• Paolo Lo Meo

Beilstein J. Org. Chem. 2019, 15, 633–641, doi:10.3762/bjoc.15.59

• Avance III (600 MHz) spectrometer; the solid-state spectra were acquired with a 15 kHz rotating MAS probe. High resolution ESI mass spectra were acquired in positive mode on an AGILENT Technologies 6540 UHD Accurate Mass Q-TOF LC–MS apparatus (1 kV nozzle voltage, 175 V fragmentor voltage). Synthesis of

Synthesis of the aglycon of scorzodihydrostilbenes B and D

• Katja Weimann and
• Manfred Braun

Beilstein J. Org. Chem. 2019, 15, 610–616, doi:10.3762/bjoc.15.56

• apparatus. NMR spectra were recorded with Bruker DXR 600 and DXR 300 spectrometers. Mass spectra were recorded on ion-trap API mass spectrometer Finnigan LCQ Deca (ESI), triple-quadrupole-mass spectrometer Finnigan TSQ 7000, and sector field mass spectrometer Finnigan MAT 8200 (EI, 70 eV), Thermo Finnigan

• ); 13C NMR (CDCl3, 150 MHz) δ 30.8, 32.6, 36.3, 55.9, 56.1, 70.3, 70.1, 110.8, 111.3, 112.0, 112.7, 120.5, 127.3, 127.3, 127.5, 127.5, 128.1, 128.1, 128.5, 128.7, 128.7, 133.7, 135.2, 137.0, 137.4, 147.3, 148.9, 149.2, 151.5, 205.4; HRMS (ESI): [M + H]+ calcd for C32H33O5, 497.2328; found, 497.2321. 1

• ), 7.45 (m, 2H); 13C NMR (CDCl3, 150 MHz) δ 30.8, 32.6, 36.3, 55.9, 70.3, 70.1, 110.8, 111.3, 112.0, 112.7, 120.5, 127.3, 127.3, 127.5, 127.5, 128.1, 128.1, 128.5, 128.7, 128.7, 128.7, 128.7, 133.7, 135.2, 137.0, 137.4, 147.3, 148.9, 149.2, 151.5, 205.4; HRMS (ESI): [M + H]+ calcd for C31H31O4, 467.2222

Cyclopropene derivatives of aminosugars for metabolic glycoengineering

• Jessica Hassenrück and
• Valentin Wittmann

Beilstein J. Org. Chem. 2019, 15, 584–601, doi:10.3762/bjoc.15.54

• , HSQC, and HMBC). Analytical RP-HPLC-MS was performed on an LCMS2020 prominence system (pumps LC-20AD, column oven CTO-20AC, UV–vis detector SPD-20A, RF-20A Prominence fluorescence detector (λex = 372 nm, λem = 456 nm), controller CBM-20A, ESI detector, software LC-solution) from Shimadzu under the

• negative mode. The ionization method was electrospray (ESI) and for detection the time of flight (TOF) method was used. Analysis of recorded mass spectra was performed using the software Xcalibur by Thermo Fischer Scientific. 2,5-Dioxopyrrolidin-1-yl 2-methylcyclopropane-1-carboxylate (3): N

Synthesis and selected transformations of 2-unsubstituted 1-(adamantyloxy)imidazole 3-oxides: straightforward access to non-symmetric 1,3-dialkoxyimidazolium salts

• Grzegorz Mlostoń,
• Małgorzata Celeda,
• Katarzyna Urbaniak,
• Marcin Jasiński,
• Vladyslav Bakhonsky,
• Peter R. Schreiner and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2019, 15, 497–505, doi:10.3762/bjoc.15.43

• −1; HRMS (ESI+): calcd. for [C15H23N2O]+, 247.1810; found, 247.1811. Sulfur-transfer reactions; Preparation of 3H-imidazole-2-thiones 10 – general procedure: A solution of the corresponding imidazole N-oxide 7 (1 mmol) in 3 mL of CH2Cl2 was treated with 103 mg (0.6 mmol) of dithione 11a and the

• =), 157.4 (C=S) ppm; IR υ: 3065 (m), 2907 (vs), 2853 (m), 1493 (vs), 1428 (m), 1399 (m), 1367 (m), 1248 (s), 1046 (vs), 889 (s), 900 (s), 773 (s), 743 (vs), 698 (vs), 577 (m) cm−1; HRMS (ESI+): calcd. for [C15H23N2OS]+, 279.1531; found, 279.1532. Preparation of non-symmetric 1,3-dialkoxyimidazolium bromides

• , HC(2)) ppm; 13C NMR δ 7.3, 8.8, 13.9 (3CH3), 22.4, 27.5, 27.8 (3CH2(p)), 31.2 (3CH(ad)), 35.4, 40.7 (6CH2(ad)), 83.9 (CH2-O), 91.5 (Cq(ad)-O), 120.0, 123.8 (2C=), 131.3 (HC(2)) ppm; IR υ: 2952 (s), 2911 (s), 1628 (m), 1373 (m), 1356 (m), 1039 (s), 958 (s), 877 (s), 593 (s) cm−1; HRMS (ESI+): calcd

Synthesis and fluorescent properties of N(9)-alkylated 2-amino-6-triazolylpurines and 7-deazapurines

• Andrejs Šišuļins,
• Jonas Bucevičius,
• Yu-Ting Tseng,
• Irina Novosjolova,
• Kaspars Traskovskis,
• Ērika Bizdēna,
• Huan-Tsung Chang,
• Sigitas Tumkevičius and
• Māris Turks

Beilstein J. Org. Chem. 2019, 15, 474–489, doi:10.3762/bjoc.15.41

• Dual-ESI Q-TOF 6520 (Agilent Technologies) mass spectrometer and Agilent 1290 Infinity series UPLC system equipped with column Extend C18 RRHD 2.1 × 50 mm, 1.8 µm connected to an Agilent 6230 TOF LC/MS masspectrometer. For HPLC analysis we used an Agilent Technologies 1200 Series chromatograph equipped

• , CDCl3) δ 153.3, 152.9, 151.7, 145.9, 130.8, 44.7, 31.6, 29.8, 28.6, 26.6, 22.5, 14.0 ppm; HRMS–ESI (m/z): [M + H]+ calcd for C12H17Cl2N4, 287.0825; found, 287.0826. Azidation: NaN3 (5.88 g, 90.5 mmol, 3.0 equiv) was added to a solution of 9-alkyl-2,6-dichloro-9H-purine (30 mmol, 1.0 equiv) in acetone

• , 26.6, 22.6, 14.1 ppm; HRMS–ESI (m/z): [M + H]+ calcd for C12H17N10, 301.1632; found, 301.1646. Synthesis of 9-alkyl-6-azido-2-pyrrolidino-9H-purine or 9-alkyl-6-azido-2-piperidino-9H-purine derivatives 6a,b: 9-Alkyl-2,6-diazido-9H-purine 2 (8.3 mmol, 1.0 equiv) was dissolved in DMF (30 mL), pyrrolidine

Synthesis of C₃-symmetric star-shaped molecules containing α-amino acids and dipeptides via Negishi coupling as a key step

• Sambasivarao Kotha and
• Saidulu Todeti

Beilstein J. Org. Chem. 2019, 15, 371–377, doi:10.3762/bjoc.15.33

• resonance (13C NMR, 100 MHz and 125 MHz) spectra were recorded on a Bruker spectrometer. The high-resolution mass measurements were carried out by using electrospray ionization (ESI) spectrometer. Melting points were recorded on a Veego melting point apparatus. Negishi coupling product 10 Zinc (Zn) dust was

• 7.75 (s, 3H), 7.64 (d, J = 8.0 Hz, 6H), 7.28 (d, J = 8.0 Hz, 6H), 5.14 (d, J = 8.0 Hz, 3H), 4.67 (d, J = 6.8 Hz, 3H), 3.77 (s, 9H), 3.24–3.11 (m, 6H), 1.45 (s, 27H) ppm; 13C NMR (100 MHz, CDCl3) δ 172.4, 155.2, 141.9, 139.8, 135.5, 129.9, 127.4, 124.9, 80.0, 54.5, 52.3, 38.0, 28.3 ppm; HRMS–ESI (Q-Tof

• , 127.6, 125.0, 53.6, 52.6, 37.7 ppm; HRMS–ESI (Q-Tof, m/z): [M + H]+ calcd for C51H46N3O9S3, 940.2391; found, 940.2392; IR (neat) : 3769, 3327, 2932, 1664, 1169, 759 cm−1. Dipeptide 12 Colorless solid; yield 73% (97 mg, starting from 100 mg of 10); Rf = 0.59 (6:4 ethyl acetate/petroleum ether); mp <230

First synthesis of cryptands with sucrose scaffold

• Patrycja Sokołowska,
• Michał Kowalski and
• Sławomir Jarosz

Beilstein J. Org. Chem. 2019, 15, 210–217, doi:10.3762/bjoc.15.20

• ), 72.7 (C6’), 72.4, 71.4, 71.3, 71.0, 70.8, 70.5, 70.5 (C-7, C-8, C-9, C-7’, C-8’, C9’, C1’), 70.6 (C-5), 69.7 (C-6), 42.8, 42.7 (2 × CH2Cl) ppm; HRMS (ESI) [M + Na]+ calcd for C62H72O13Cl2Na, 1117.4248; found, 1117.4211; anal. calcd for C62H72O13Cl2 (1096.15): C, 67.94; H, 6.62; Cl, 6.47; found: C

• , 72.9, 72.3 (5 × OCH2Ph), 72.7 (C6’), 72.4, 72.0, 71.9, 70.8, 70.8, 70.1, 70.1 (C-7, C-8, C-9, C-7’, C-8’, C9’, C1’), 70.6 (C-5), 69.7 (C-6), 3.1, 2.9 (2 × CH2I) ppm; HRMS (ESI) [M + Na]+ calcd for C62H72O13I2Na, 1301.2960; found, 1301.2955; anal. calcd for C62H72O13I2 (1279.05): C, 58.22; H, 5.67; I

• (C-5’), 77.7 (C-4), 74.9, 74.2, 73.0, 72.7, 72.0, 71.5 (6 × OCH2Ph), 72.4 (C-1’), 71.37 (C-7’), 71.06 (C-6’), 70.7 (C-5), 69.9 (C-7), 69.7 (C-6), 58.4, 53.9, 53.6, 53.0, 52.9, 49.8 (6 × CH2N) ppm; HRMS (ESI) [M + H]+ calcd for C74H97N2O17, 1285.6787; found, 1285.6803. 1’,6,6’-Tri-O-allyl-2,3,3’,4,4

Silanediol versus chlorosilanol: hydrolyses and hydrogen-bonding catalyses with fenchole-based silanes

• Falco Fox,
• Jörg M. Neudörfl and
• Bernd Goldfuss

Beilstein J. Org. Chem. 2019, 15, 167–186, doi:10.3762/bjoc.15.17

• , 21.49, 20.63, 19.33, 19.18; 29Si NMR (60 MHz, CDCl3, 25 °C, TMS) δ −21.93; MS (HRMS ESI) m/z: [M + Na]+ calcd for C32H41O3ClNaSi, 559.2405; found, 559.2404 (−0.1 ppm). Synthesis BIFOXSi(OH)2 (9): In a dried Schlenk flask BIFOXSiCl2 (7, 1 g, 1.8 mmol, 1 equiv) was solved in THF (25 mL) and H2O (25 mL

• ), 0.59 (s, 6H), 0.45 (s, 6H); 13C NMR (75 MHz, CDCl3, 25 °C, TMS) δ 144.28, 141.97, 135.16, 128.80, 124.70, 124.17, 90.24, 55.04, 50.08, 48.11, 43.98, 35.33, 29.01, 23.65, 20.85, 19.76; MS (HRMS ESI) m/z: [M + Na]+ calcd for C32H42O4NaSi, 541.2744; found, 541.2742 (−0.4 ppm); 29Si NMR (60 MHz, CDCl3, 25

Synthesis of a tubugi-1-toxin conjugate by a modulizable disulfide linker system with a neuropeptide Y analogue showing selectivity for hY1R-overexpressing tumor cells

• Rainer Kufka,
• Robert Rennert,
• Goran N. Kaluđerović,
• Lutz Weber,
• Wolfgang Richter and
• Ludger A. Wessjohann

Beilstein J. Org. Chem. 2019, 15, 96–105, doi:10.3762/bjoc.15.11

• conjugate 8 was characterized by ESI–FTICR–MS measurements (see Supporting Information File 1). All signals for [M + nH]n+ with n = 4–8 could be identified. After NPY Y1 receptor-mediated, endocytotic accumulation of the respective peptide–toxin conjugate 8 in the targeted tumor cells, the cytotoxic tubugi

Fabrication of supramolecular cyclodextrin–fullerene nonwovens by electrospinning

• Hiroaki Yoshida,
• Ken Kikuta and
• Toshiyuki Kida

Beilstein J. Org. Chem. 2019, 15, 89–95, doi:10.3762/bjoc.15.10

• downsizing C60 with bowl milling [26] and high-speed vibration milling [27]. We confirmed that a simple grinding process by an agate mortar is sufficient for the HFIP system (Figure S2 in Supporting Information File 1). ESI mass spectrometry of the purple solution indicates the presence of the γ-CD–C60 (2:1

• detected even after the nonwovens were stored in toluene for three days (Figure S10 in Supporting Information File 1). The other aimed examined the solution of the nonwovens re-dissolved with HFIP. The resulting purple solution clearly provides the same UV–vis absorption and ESI mass results as the

• spectroscopy (V-730, JASCO, Japan), ESI mass spectroscopy (Autoflex III, Bruker), and small sample viscometry (m-VROCTM, RheoSense, USA). γ-CD/HFIP (15 w/v %; 500 μL) and C60/toluene (0, 0.14, 0.29, 0.43, 0.58, 0.72 mM; 25 μL) were mixed and measured by UV–vis spectrometry. The calibration curve was prepared

Mechanistic studies of an L-proline-catalyzed pyridazine formation involving a Diels–Alder reaction with inverse electron demand

• Anne Schnell,
• J. Alexander Willms,
• S. Nozinovic and
• Marianne Engeser

Beilstein J. Org. Chem. 2019, 15, 30–43, doi:10.3762/bjoc.15.3

• charge-tagged proline catalyst. The charge-tagging technique strongly increases the ESI response of the respective species and therefore enables to capture otherwise undetected reaction components. With the first two reaction variants, only small intensities of intermediates were found, but the temporal

• ; L-proline; reaction mechanism; Introduction Electrospray (ESI) mass spectrometry (MS) [1] is well suited for studying reaction mechanisms as it is a soft ionization method leaving most species intact [1][2][3]. In addition, it is a fast analytical method [3] making it possible to study transient

• with liquid or gas chromatography. Further, ESI signal intensities do not directly correlate to concentrations in solution, but to the ESI response of the pertaining molecules [3][22]. The ESI response is influenced by a variety of factors like chargeability and surface activity of a given analyte and

A simple and effective preparation of quercetin pentamethyl ether from quercetin

• Jin Tatsuzaki,
• Tomohiko Ohwada,
• Yuko Otani,
• Reiko Inagi and
• Tsutomu Ishikawa

Beilstein J. Org. Chem. 2018, 14, 3112–3121, doi:10.3762/bjoc.14.291

• the solvent peak for the 1H and 13C NMR spectra. The following abbreviations are used: s = singlet, d = doublet, t = triplet, q = quartet, dd = double doublet. Electron spray ionization time-of-flight mass spectra (ESI–TOF MS) were recorded on a Bruker micrOTOF-05 to give high-resolution mass spectra

Thermophilic phosphoribosyltransferases Thermus thermophilus HB27 in nucleotide synthesis

• Ilja V. Fateev,
• Ekaterina V. Sinitsina,
• Aiguzel U. Bikanasova,
• Maria A. Kostromina,
• Elena S. Tuzova,
• Larisa V. Esipova,
• Tatiana I. Muravyova,
• Alexei L. Kayushin,
• Irina D. Konstantinova and
• Roman S. Esipov

Beilstein J. Org. Chem. 2018, 14, 3098–3105, doi:10.3762/bjoc.14.289

• sequence). Mass spectra were measured on an Agilent 6224, ESI-TOF, LC/MS (USA) in positive ion mode (ESI), LCQ Fleet ion trap mass spectrometer (Thermo Electron, USA) and Agilent 1100 LC/MSD VL (Agilent Technologies) equipped an APCI and ESI source (positive and negative mode of ionization), 1100 DAD and

• ; 37%) of 9-(β-D-ribofuranosyl)-2-chloroadenine 5'-monophosphate of 99% purity (HPLC). HRMS (ESI+): m/z [M + H]+ calcd for C10H13N5O7P1Cl1: 382.0315; found, 382.0353; [2M + H]+, found, 763.0606; [Base + H]+, found, 170.0244; 1Н NMR (DMSО-d6) δ ppm) 8.52 (s, 1Н, H8), 7.78 (br. s., 2H, NH2), 5.83 (d, J1

• -ribofuranosyl)pyrazolo[3,4-d]pyrimidine-4-one 5'-monophosphate of 97% purity (HPLC). HRMS (ESI+): m/z [M + H]+ calcd for C10H13N4O8P1: 349.0545; found, 349.0520; [2M + H]+, found, 697.0952; [3M + H]+, found, 1045.1374; [Base + H]+ found, 137.0453; 1Н NMR (DMSО-d6) δ 12.44 (br. s, 1H, NH), 8.15 (s, 1H, H3), 8.13

N-Acylated amino acid methyl esters from marine Roseobacter group bacteria

• Hilke Bruns,
• Lisa Ziesche,
• Nargis Khakin Taniwal,
• Laura Wolter,
• Thorsten Brinkhoff,
• Jennifer Herrmann,
• Rolf Müller and
• Stefan Schulz

Beilstein J. Org. Chem. 2018, 14, 2964–2973, doi:10.3762/bjoc.14.276

• and ESI mass spectra revealed fragmentation patterns helpful for the detection of similar compounds derived from other amino acids. Some of these compounds showed antimicrobial activity. The structural similarity of N-acylated amino acid methyl esters and similar lipophilicity to AHLs might indicate a

• :1-NAVME. The extract of Roseovarius sp. D12_1.68 was also investigated by HPLC/ESI+–MS to detect more polar compounds compared to GC. The NAMEs, NABMEs and NAVMEs reported here were detected by MS2 analyses based on their characteristic fragmentation (see below). The only oxygenated derivative

• the three strains. Mass spectrometry The analysis of the mass spectra of NAMEs, NABMEs, NAVMEs, and NAGMEs revealed the typical fragmentation of N-acylated amino acid methyl esters under both EI (Figure 7) and ESI ionization (Figure 8). Detailed structural information can be obtained by EI-MS. A

Olefin metathesis catalysts embedded in β-barrel proteins: creating artificial metalloproteins for olefin metathesis

• Daniel F. Sauer,
• Johannes Schiffels,
• Takashi Hayashi,
• Ulrich Schwaneberg and
• Jun Okuda

Beilstein J. Org. Chem. 2018, 14, 2861–2871, doi:10.3762/bjoc.14.265

• nm indicated the presence of the GH-type catalyst. Finally, the peak for the biohybrid conjugate was observed in ESI–TOF–MS suggesting successful covalent anchoring. Beside ring-closing metathesis (RCM) of 2,2-diallylpropane-1,3-diol to yield the corresponding cyclopentane derivative, the synthesized

Unprecedented nucleophile-promoted 1,7-S or Se shift reactions under Pummerer reaction conditions of 4-alkenyl-3-sulfinylmethylpyrroles

• Takashi Go,
• Akane Morimatsu,
• Hiroaki Wasada,
• Genzoh Tanabe,
• Osamu Muraoka,
• Yoshiharu Sawada and
• Mitsuhiro Yoshimatsu

Beilstein J. Org. Chem. 2018, 14, 2722–2729, doi:10.3762/bjoc.14.250

• with p-methoxybenzenethiol/TBAH, which exclusively produced 9a (the diol 24a was not detected by ESI mass spectroscopy). A similar result was obtained from the reaction of 5a with p-chlorobenzenethiol/TBAH. These results support the hypothesis that the reaction proceeds via the initial formation of the

Domino ring-opening–ring-closing enyne metathesis vs enyne metathesis of norbornene derivatives with alkynyl side chains. Construction of condensed polycarbocycles

• Ritabrata Datta and
• Subrata Ghosh

Beilstein J. Org. Chem. 2018, 14, 2708–2714, doi:10.3762/bjoc.14.248

• (s, 6H); 13C NMR (125 MHz) δ 144.3, 139.8, 136.4, 136.1, 117.0, 113.1, 71.9, 68.6, 63.4, 61.2, 52.2, 52.0, 45.8, 36.8, 36.0, 33.8, 28.8, 26.0 (× 3), 18.4, −5.4, −5.6; HRMS–ESI m/z: [M + Na]+ calcd for C23H38O2SiNa 397.2539; found, 397.2537. Diels–Alder reaction of diene 11. Synthesis of adduct 14. A

• , 9H), 0.08 (s, 6H); 13C NMR (75 MHz) δ 169.0, 168.7, 136.4, 135.8, 133.6, 132.4, 132.2, 117.9, 72.0, 68.8, 63.1, 61.2, 52.3 (× 2), 52.1 (× 2), 45.7, 41.1, 36.8, 33.6, 30.9, 28.9, 28.6, 26.0 (× 3), 18.4, −5.4, −5.6; IR: 2952, 1728, 1471 cm−1; HRMS–ESI m/z: [M + Na]+ calcd for C29H44O6SiNa 539.2805

• , 1249 cm−1; HRMS–ESI m/z: [M + Na]+ calcd for C31H46O7SiNa 581.2911; found, 581.2914. Synthesis of the tetracycle 20. The dienyne 18 (100 mg, 0.25 mmol) in degassed anhydrous toluene (7 mL) was treated with Grubbs’ catalyst G-II (22 mg, 0.025 mmol) at 65 °C for 5 h. On completion of the reaction (TLC