The use of 4,4,4-trifluorothreonine to stabilize extended peptide structures and mimic β-strands

• Yaochun Xu,
• Isabelle Correia,
• Tap Ha-Duong,
• Nadjib Kihal,
• Jean-Louis Soulier,
• Julia Kaffy,
• Benoît Crousse,
• Olivier Lequin and
• Sandrine Ongeri

Beilstein J. Org. Chem. 2017, 13, 2842–2853, doi:10.3762/bjoc.13.276

• activity [3][4]. Fluorinated amino acids can also be used as powerful 19F NMR probes for the study of protein–ligand interactions and enzymatic activities [5][6][7][8]. However, the development of fluorinated peptides as drug candidates seems to be largely under-exploited. Investigation on the influence of

• straightforward methodology and we have adapted Zeng’s synthesis starting from the (R)-Garner’s aldehyde. (2S,3R)-Boc-CF3-Thr(Bzl) was obtained with satisfactory yields (Scheme 1). In this synthetic pathway, the key intermediate 6 was obtained, as a mixture of two diastereoisomers (9:1, evaluated by 19F NMR) via

• release of free (2S,3S)-CF3-threonine whose diastereoselectivity was determined to be about 96% by 19F NMR. Although in most of the reported cases, the free amino acid was released into the aqueous phase, and then purified by ion-exchange chromatography, we purified the free (2S,3S)-CF3-threonine by

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation. Part 1: Use of CF₃SO₂Na

• Hélène Guyon,
• Hélène Chachignon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2764–2799, doi:10.3762/bjoc.13.272

• allowing access to various β-trifluoromethyl ketones 24 featuring aryl, alkyl, functionalised alkyl, alkenyl, acetal, silylated alcohol, pyran, and piperidine functionalities (R group in 24). Mechanistic studies by 19F NMR allowed to identify CF3 complexes of copper(I) and copper(III) and the predominance

Development of a fluorogenic small substrate for dipeptidyl peptidase-4

• Futa Ogawa,
• Masanori Takeda,
• Kanae Miyanaga,
• Keita Tani,
• Ryuji Yamazawa,
• Kiyoshi Ito,
• Atsushi Tarui,
• Kazuyuki Sato and
• Masaaki Omote

Beilstein J. Org. Chem. 2017, 13, 2690–2697, doi:10.3762/bjoc.13.267

• (4 Å). All commercially available materials were used as received without further purification. 1H NMR, 13C NMR and 19F NMR spectra were measured on a JEOL ECZS 400S spectrometer (1H: 400MHz, 13C: 100 MHz, 19F: 376 MHz). Chemical shifts of 1H NMR and 13C NMR are reported in parts per million from

• tetramethylsilane (TMS), used as an internal standard at 0 ppm. Chemical shifts of 19F NMR are reported in parts per million from trichlorofluoromethane (CFCl3), used as an internal standard at 0 ppm. All dates are reported as follows: chemical shifts, relative integration value, multiplicity (s = singlet, d

• = 2.1, 15.8 Hz, 1H), 7.30 (dd, J = 1.8, 8.2 Hz, 1H), 7.36 (d, J = 1.8 Hz, 1H); 13C NMR (CDCl3) δ 112.9 (q, J = 33.7 Hz), 116.8, 117.9 (q, J = 33.7 Hz), 119.2, 123.3 (q, J = 269.4 Hz), 123.9 (q, J = 269.4 Hz), 124.4, 127.9, 132.7 (q, J = 6.7 Hz), 136.8 (q, J = 6.7 Hz), 146.3; 19F NMR (CDCl3) δ 89.84 (dd

Ring-size-selective construction of fluorine-containing carbocycles via intramolecular iodoarylation of 1,1-difluoro-1-alkenes

• Takeshi Fujita,
• Ryo Kinoshita,
• Tsuyoshi Takanohashi,
• Naoto Suzuki and
• Junji Ichikawa

Beilstein J. Org. Chem. 2017, 13, 2682–2689, doi:10.3762/bjoc.13.266

• . Experimental General: 1H NMR, 13C NMR, and 19F NMR spectra were recorded on a Bruker Avance 500 or a JEOL ECS-400 spectrometer. Chemical shift values are given in ppm relative to internal Me4Si (for 1H NMR: δ = 0.00 ppm), CDCl3 (for 13C NMR: δ = 77.0 ppm), C6F6 (for 19F NMR: δ = 0.0 ppm), and (4-MeC6H4)2C(CF3

• )2 (for 19F NMR: δ = 97.9 ppm). IR spectra were recorded on a Horiba FT-300S spectrometer using the attenuated total reflectance (ATR) method. Mass spectra were measured on a JEOL JMS-T100GCV spectrometer. X-ray diffraction studies were performed on a Bruker APEXII ULTRA instrument equipped with a

• , 134.6, 136.8; 19F NMR (470 MHz, CDCl3) δ 124.7 (br s); IR (neat): 3068, 1489, 1454, 1126, 1147, 1097, 964, 850, 742, 696, 592 cm−1; HRMS–EI (m/z): [M]+ calcd for C21H15F2I, 432.0186; found: 432.0166. Typical procedure for the iodoarylation of 2-(3,3-difluoroallyl)biaryls 5: To a HFIP (2.5 mL) and

Electrophilic trifluoromethylselenolation of terminal alkynes with Se-(trifluoromethyl) 4-methylbenzenesulfonoselenoate

• Clément Ghiazza,
• Anis Tlili and
• Thierry Billard

Beilstein J. Org. Chem. 2017, 13, 2626–2630, doi:10.3762/bjoc.13.260

• reaction was stirred at 25 °C for 15–18 hours (conversion was checked by 19F NMR with PhOCF3 as internal standard). The crude residue was purified by chromatography to afford the desired products 3–5. Single-crystal X-ray structure of 3a. Electrophilic addition of 1a to alkynes. Yields shown are those of

• isolated products; yields determined by 19F NMR spectroscopy with PhOCF3 as an internal standard are shown in parentheses. Mechanism proposal. Perfluoroalkylselenolation of alkynes. Yields shown are those of isolated products; yields determined by 19F NMR spectroscopy with PhOCF3 as an internal standard

Regioselective decarboxylative addition of malonic acid and its mono(thio)esters to 4-trifluoromethylpyrimidin-2(1H)-ones

• Sergii V. Melnykov,
• Andrii S. Pataman,
• Yurii V. Dmytriv,
• Svitlana V. Shishkina,
• Mykhailo V. Vovk and
• Volodymyr A. Sukach

Beilstein J. Org. Chem. 2017, 13, 2617–2625, doi:10.3762/bjoc.13.259

• Organofluorine compounds now play an essential role in the development of new materials for solar cells [1][2][3], radiotracers for PET imaging [4], agrochemicals [5][6], sensitive chemical probes for 19F nuclear magnetic resonance investigation of biological experiments [7][8], and are most widely used in the

• Michael-type regioisomer 5a (Table 1, entry 1). The reaction course and the ratio of the regioisomers formed were conveniently monitored by 19F NMR spectroscopy. Acid 4a precipitated in pure form on evaporating toluene and treating the residue with diluted hydrochloric acid. Performing the reaction in a

• reaction in toluene in the presence of TEA (1 equiv) at 80 °C for 4 hours gave the best result in terms of regioselectivity and yield of 6a (Table 3, entry 1), virtually the only product formed in all the solvents used here (as evidenced by 19F NMR monitoring). The addition of malonic acid monophenyl ester

Palladium-catalyzed Heck-type reaction of secondary trifluoromethylated alkyl bromides

• Tao Fan,
• Wei-Dong Meng and
• Xingang Zhang

Beilstein J. Org. Chem. 2017, 13, 2610–2616, doi:10.3762/bjoc.13.258

• Pd-catalyzed cross-coupling between 1a and 2-bromo-1,1,1-trifluorohexane (2a)a. Supporting Information Supporting Information File 400: General experimental information, experimental details on the synthesis of compounds 2–4 and 6; full characterization data as well as 1H/ 19F/ 13C NMR spectra of

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

• = triplet, q = quartet, p = pentet, m = multiplet, br. s = broad singlet, app = apparent. Data for 13C NMR are reported in terms of chemical shift (δ ppm) and multiplicity (C, CH, CH2 or CH3). Data for 19F NMR were recorded on the above instruments at a frequency of 376 MHz using CFCl3 as external standard

• 162.8 (C), 147.6 (C), 133.3 (q, J = 35 Hz, C), 132.4 (CH), 131.0 (q, J = 4 Hz, CH), 128.9 (C), 123.7 (q, J = 4 Hz, CH), 122.2 (q, J = 273 Hz, C), 113.8 (C), 64.4 (CH2), 41.2 (CH), 13.9 (CH3); 19F NMR (376 MHz, CDCl3) δ −63.2; IR (neat) ν/cm−1: 3092 (w), 2925 (w), 1732 (m), 1537 (m), 1502 (m), 1357 (m

• 164.4 (C), 135.8 (d, J = 3 Hz, CH), 128.7 (C), 125.4 (q, J = 273 Hz, C), 123.3 (q, J = 34 Hz, C), 121.75 (CH), 118.0 (q, J = 4 Hz, CH), 117.6 (C), 110.3 (q, J = 4 Hz, CH), 107.5 (C), 59.8 (CH2), 14.9 (CH3); 19F NMR (376 MHz, DMSO-d6) δ −59.3; IR (neat) ν/cm−1: 3196 (m), 1667 (s), 1514 (m), 1440 (m

¹⁵N-Labelling and structure determination of adamantylated azolo-azines in solution

• Sergey L. Deev,
• Alexander S. Paramonov,
• Tatyana S. Shestakova,
• Igor A. Khalymbadzha,
• Oleg N. Chupakhin,
• Julia O. Subbotina,
• Oleg S. Eltsov,
• Pavel A. Slepukhin,
• Vladimir L. Rusinov,
• Alexander S. Arseniev and
• Zakhar O. Shenkarev

Beilstein J. Org. Chem. 2017, 13, 2535–2548, doi:10.3762/bjoc.13.250

• spin–spin interactions (see below). The 13C assignment procedure for 19-15N2, 20-15N2, and 21a,b-15N2 was aided by the data from a previous study of unlabelled derivatives of compound 19 [12]. The 13C-19F J-coupling constants (nJCF, Table 2) observed in the 1D 13C spectra facilitated the assignment of

• , 13C-15N and 13C-19F J-coupling constants (Hz) of the studied compoundsa. Supporting Information Supporting Information File 470: Detailed experimental procedures, the synthesis of labelled compounds, crystallographic information for 15a-15N2 and 15b-15N2, computational data, and 1D 1H, 13C and 2D 15N

One-pot three-component route for the synthesis of S-trifluoromethyl dithiocarbamates using Togni’s reagent

• Azim Ziyaei Halimehjani,
• Martin Dračínský and
• Petr Beier

Beilstein J. Org. Chem. 2017, 13, 2502–2508, doi:10.3762/bjoc.13.247

• using IR, 1H NMR, 13C NMR, 19F NMR and HRMS analysis. The dithiocarbamate moiety in S-trifluoromethyl dithiocarbamates appeared at 180–185 ppm in the 13C NMR spectra, while this group usually can be found at 190–200 ppm for S-alkyl dithiocarbamates [4][5][6][7][8][9][10][11][12]. Also the carbon of the

• CF3 group was observed at around 128 ppm as quartet with a coupling constant of ≈308 Hz. In addition, a singlet at −40 ppm in the 19F NMR spectra was assigned to the CF3 group. The one-pot reaction of benzylamine with CS2 and Togni's reagent I under optimal reaction conditions was also investigated

• , and 19F NMR spectra of all compounds. Acknowledgements We are grateful to the faculty of chemistry of Kharazmi University for supporting this work. This work was also supported by the Academy of Sciences of the Czech Republic (Research Plan RVO: 61388963) and Ministry of Education of the Czech

Syntheses, structures, and stabilities of aliphatic and aromatic fluorous iodine(I) and iodine(III) compounds: the role of iodine Lewis basicity

• Tathagata Mukherjee,
• Soumik Biswas,
• Andreas Ehnbom,
• Subrata K. Ghosh,
• Ibrahim El-Zoghbi,
• Nattamai Bhuvanesh,
• Hassan S. Bazzi and
• John A. Gladysz

Beilstein J. Org. Chem. 2017, 13, 2486–2501, doi:10.3762/bjoc.13.246

• analogous reaction at room temperature gave Rf15CH2OTf in 22% yield. The triflates were white solids with some solubility in acetone. They were characterized by IR and NMR (1H, 13C{1H}, 19F{1H}) spectroscopy and microanalyses as summarized in the experimental section. The triflates were treated with NaI in

• , 67.46; S, 4.38; found: C, 21.44; H, 0.31; F, 67.21; S, 4.15; 1H NMR (500 MHz, acetone-d6) δ 5.55 (t, 3JHF = 13 Hz, 2H, CH2); 19F{1H} NMR (470 MHz, acetone-d6) δ −75.5 (s, 3F, SO2CF3), −81.7 (t, 4JFF = 10 Hz [60][61][62], 3F, CF3), −120.2 (m, 2F, CF2), −122.2 (m, 12F, 6CF2), −123.2 (m, 4F, 2CF2), −126.7

• , acetone-d6) δ 4.06 (t, 3JHF = 19 Hz, 2H, CH2); 19F{1H} NMR (470 MHz, acetone-d6) δ −81.6 (t, 4JFF = 10 Hz [60][61][62], 3F, CF3), −107.0 (m, 2F, CF2), −122.2 (m, 14F, 7CF2), −123.2 (m, 2F, CF2), −126.7 (m, 2F, CF2); 13C{1H} NMR (125 MHz, acetone-d6, partial) δ −3.8 (t, 2JCF = 25 Hz, CH2); IR (powder film

Diastereoselective Mannich reactions of pseudo-C₂-symmetric glutarimide with activated imines

• Tatsuya Ishikawa,
• Tomoko Kawasaki-Takasuka,
• Toshio Kubota and
• Takashi Yamazaki

Beilstein J. Org. Chem. 2017, 13, 2473–2477, doi:10.3762/bjoc.13.244

• % yield as determined by 19F NMR (Table 1, entry 3). NaHMDS (Table 1, entry 4) or LiHMDS (Table 1, entry 5) instead of LDA worked properly affording 3a in a yield of 59 or 80%, respectively. The product 3a theoretically consists of 8 diastereomers and usually 2 isomers predominated with a couple of minor

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

• Vladimir Kubyshkin Nediljko Budisa Biocatalysis group, Institute of Chemistry, Technical University of Berlin, Müller-Breslau-Strasse 10, Berlin 10623, Germany 10.3762/bjoc.13.241 Abstract Fluorinated moieties are highly valuable to chemists due to the sensitive NMR detectability of the 19F

• background in spectroscopic observations of biological samples. This feature is especially beneficial for NMR applications because the sole stable fluorine isotope (19F) has the third largest magnetogyric ratio among the nuclei measured by NMR (after 3H and 1H hydrogen isotopes); as a result, 19F NMR

• experiments are remarkably sensitive [4]. Fluorine-containing groups can be incorporated into biopolymers by various approaches, including those that utilize biosynthesis [5][6][7], enzymatic conversion [8], chemical synthesis [9][10], and ligation reactions [11]. Depending on the research target, 19F NMR

Fluorination of some highly functionalized cycloalkanes: chemoselectivity and substrate dependence

• Attila Márió Remete,
• Melinda Nonn,
• Santos Fustero,
• Matti Haukka,
• Ferenc Fülöp and
• Loránd Kiss

Beilstein J. Org. Chem. 2017, 13, 2364–2371, doi:10.3762/bjoc.13.233

• 60 F254 was purchased from Merck. The NMR spectra were acquired at room temperature on a Bruker Avance 400 spectrometer with 11.75 T magnetic field strength (1H frequency: 400.13 MHz, 19F frequency: 376.50 MHz, 13C frequency: 100.76 MHz, respectively) in CDCl3 or DMSO-d6 solution, using the deuterium

• signal of the solvent to lock the field. The 1H and 13C chemical shifts are given relative to TMS and 19F chemical shifts are referenced to CFCl3 (0.00 ppm). General procedures for fluorination Method A: To a solution of dihydroxylated compound (0.50 mmol) in 10 mL anhydrous CH2Cl2 under an Ar atmosphere

Homologated amino acids with three vicinal fluorines positioned along the backbone: development of a stereoselective synthesis

• Raju Cheerlavancha,
• Ahmed Ahmed,
• Yun Cheuk Leung,
• Aggie Lawer,
• Qing-Quan Liu,
• Marina Cagnes,
• Hee-Chan Jang,
• Xiang-Guo Hu and
• Luke Hunter

Beilstein J. Org. Chem. 2017, 13, 2316–2325, doi:10.3762/bjoc.13.228

• ketones [31]. However, 1H NMR and 19F NMR analysis of the crude reaction mixture revealed that the only identifiable product was the undesired gem-difluorinated compound 25 (Scheme 2), which was obtained along with a significant amount of unreacted starting material 21a (see Supporting Information File 1

• -scale final fluorination reaction was attempted (Scheme 3) because this was anticipated to converge some of the compounds into a simpler product mixture. Analysis of the crude reaction mixture by 19F NMR revealed that the desired product 29 may have been formed in small quantity. However, there was

• final compounds, which were of low molecular weight and very polar. Nevertheless, the first synthesis of a δ-amino acid containing three vicinal fluorines on the backbone had been successfully completed. The all-syn target 6b was then obtained in a similar fashion from 40b (Scheme 4). The 1H and 19F NMR

Comparative profiling of well-defined copper reagents and precursors for the trifluoromethylation of aryl iodides

• Peter T. Kaplan,
• Jessica A. Lloyd,
• Mason T. Chin and
• David A. Vicic

Beilstein J. Org. Chem. 2017, 13, 2297–2303, doi:10.3762/bjoc.13.225

• , we monitored the reactions of the iodotoluenes by quantitative 19F NMR spectroscopy. Using the same solvent systems employed for the reactions in Figure 2, conversions were measured over a 22 hour period (Figure 3). In this case, [(SIMes)Cu(CF3)] performed just as well as the [(phen)Cu(CF3

• by 1H NMR and 19F NMR for purity. Copper salt precursors were purchased from Sigma-Aldrich. Trimethyl(trifluoromethyl)silane (99% purity) was purchased from SynQuest Labs, Inc. and used without further purification. All other chemicals were verified by 1H NMR for purity and used without further

• glovebox. The quantitative NMR analyses were accomplished using a Bruker Ascend 400 MHz spectrometer by 19F NMR spectra referenced to internal standard of fluorobenzene. Solution 1H NMR spectra were recorded at ambient temperature on a Bruker Ascend 400 MHz spectrometer and referenced to residual proton

Synthesis and application of trifluoroethoxy-substituted phthalocyanines and subphthalocyanines

• Satoru Mori and
• Norio Shibata

Beilstein J. Org. Chem. 2017, 13, 2273–2296, doi:10.3762/bjoc.13.224

• TFEO-ZnPc 4 and fluorinated polymer 22 were condensed by a click reaction between azide and alkyne groups (Scheme 8). The graft ratio of the TFEO-ZnPc-supported fluoropolymer was calculated from the area ratio of 19F NMR, and the resulting fluorinated copolymers showed different grafting ratios (from

Curcuminoid–BF₂ complexes: Synthesis, fluorescence and optimization of BF₂ group cleavage

• Henning Weiss,
• Jeannine Reichel,
• Helmar Görls,
• Kilian Rolf Anton Schneider,
• Mathias Micheel,
• Michael Pröhl,
• Michael Gottschaldt,
• Benjamin Dietzek and
• Wolfgang Weigand

Beilstein J. Org. Chem. 2017, 13, 2264–2272, doi:10.3762/bjoc.13.223

• water. Because most of the compounds were partially hydrolysed when heated to 80 °C in aqueous acetone solution, we carried out the purification at room temperature. The final compounds were characterized by 1H, 11B{1H}, 13C{1H} and 19F{1H} NMR spectroscopy, EI mass spectrometry, elemental analyses as

• well as UV–vis absorption and fluorescence spectroscopy. The proton NMR spectra of all compounds exhibit the characteristic AB spin systems (J = approx. 16 Hz) occurring from the trans-olefinic protons in combination with a singlet at around 6.5 ppm. Signals in 19F{1H} NMR appeared as sharp singlets at

• around −140 ppm, while 11B{1H} NMR signals appear as up to 3 ppm broad singlets at about +0.9 ppm. No coupling between 19F and 11B nuclei was observed because of the high quadrupole moment of the 11B nucleus. Due to the high relative mass difference between both naturally occurring boron isotopes

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

• (4 mL), then DBU (0.42 mL, 2.82 mmol, 1.5 equiv) was added and the reaction mixture was stirred at room temperature. After 2 h, 19F NMR showed 100% conversion and the reaction mixture was neutralized with a saturated solution of NH4Cl. After extraction with ethyl acetate, the organic phases were

• = 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

One-pot multistep mechanochemical synthesis of fluorinated pyrazolones

• Joseph L. Howard,
• William Nicholson,
• Yerbol Sagatov and
• Duncan L. Browne

Beilstein J. Org. Chem. 2017, 13, 1950–1956, doi:10.3762/bjoc.13.189

• electron-withdrawing trifluoromethyl substituent was an exception to this (7) [31]. For this case, crude 19F NMR after the first step shows a 41% conversion, suggesting that the pyrazolone formation is the limiting factor in this example. An alkyl β-ketoester (ethyl acetoacetate) was also used, affording

Conformational impact of structural modifications in 2-fluorocyclohexanone

• Francisco A. Martins,
• Josué M. Silla and
• Matheus P. Freitas

Beilstein J. Org. Chem. 2017, 13, 1781–1787, doi:10.3762/bjoc.13.172

• 1H and TFA for 19F) in vacuum. Supporting Information Supporting Information File 158: Computational data. Acknowledgements The authors are thankful to CNPq, CAPES and FAPEMIG for the financial support of this research, as well as for the scholarship (to F.A.M.) and fellowships (to J.M.S. and M.P.F.).

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

• , 31P and 19F NMR spectroscopy, as well as IR spectroscopy and HRMS spectrometry. Next the phosphonium salts were used in the Tscherniac–Einhorn–type imidoalkylation of aromatic hydrocarbons of diverse reactivity. The reaction was carried out without a catalyst, using a considerable excess of the

• ). 1H and 13C NMR spectra were recorded at operating frequencies of 400 and 100 MHz, respectively, using TMS as internal standard. 31P and 19F NMR spectra were recorded at operating frequencies of 161.9 and 376 MHz, respectively, without the resonance shift standard, with respect to H3PO4 and CFCl3

• mass and composition for the molecular ion adducts were calculated using the MassLynx software incorporated within the instrument. Spectroscopic properties of all synthesized compounds as well as 1H NMR, 13C NMR, 31P NMR and 19F NMR spectra of all new compounds are given in Supporting Information File

Synthesis and enzymatic ketonization of the 5-(halo)-2-hydroxymuconates and 5-(halo)-2-hydroxy-2,4-pentadienoates

• Tyler M. M. Stack,
• William H. Johnson Jr. and
• Christian P. Whitman

Beilstein J. Org. Chem. 2017, 13, 1022–1031, doi:10.3762/bjoc.13.101

• comparable. Composition of the equilibrium mixture for 5b–d Dienols 5b–d were allowed to equilibrate in 100 mM Na2HPO4 buffer (final pH 6.8–7.2) in the presence of Pp 4-OT, and the identities of the components of the mixture were determined by 1H NMR spectroscopy. The 1H, 13C, and 19F NMR data are presented

• mixture stirred at ambient temperature for 16 h. The reaction mixture was filtered and the filtrate was adjusted to pH 1 by the addition of concentrated HCl. The precipitate was collected by filtration and crystallized in ethyl acetate (3c: 1.18 g and 3d: 1.56 g). The 1H, 13C, and 19F NMR data are

• azeotrope any water that is present in the methanol. The resulting solution was evaporated to dryness under reduced pressure at room temperature to yield the monoacid (5c or 5d). Titration with hexanes yields a sticky yellow solid (≈100 mg). The compounds are stored at −20 °C. The 1H, 13C, and 19F NMR data

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

• [105]. In another recent study on the development of synthetic nanosystems as potential carbohydrate-based vaccine, GAuNPs were loaded with synthetic oligosaccharide fragments corresponding to the repeating units of S. pneumoniae (Pn) CPS type 19F and 14 [106]. This new approach has explored the effect

Synthesis of ribavirin 2’-Me-C-nucleoside analogues

• Fanny Cosson,
• Aline Faroux,
• Jean-Pierre Baltaze,
• Jonathan Farjon,
• Régis Guillot,
• Jacques Uziel and
• Nadège Lubin-Germain

Beilstein J. Org. Chem. 2017, 13, 755–761, doi:10.3762/bjoc.13.74

• (triazole), 128.6, 128.2, 127.7 (Ph), 100.8 (d, J = 190 Hz, C2), 82.2 (C4), 79.7 (d, J = 39 Hz, C1), 73.9 (d, J = 23 Hz, C3), 61.3 (C5), 53.0 (-CH2Ph), 17.2 (d, J = 26 Hz, CH3); 19F NMR (376.2 MHz, MeOD) −158.2 (m); HRMS calcd for C16H20FN4O4, 351.1469; found, 351.1468. Debenzylation proceeded in ethanol (5

• ), 101.2 (d, J = 174 Hz, C2), 81.5 (C4), 78.5 (d, J = 39 Hz, C1), 72.6 (d, J = 23 Hz, C3), 60.6 (C5), 16.3 (d, J = 26 Hz, CH3); 19F NMR (376.2 MHz, MeOD) −160.8 (m); HRMS calcd for C9H14FN4O4, 261.0999; found, 261.1006. Targeted compounds. Retrosynthesis of compound 1. X-ray spectrum of compound 10b