Attempted synthesis of a meta-metalated calix[4]arene

• Christopher D. Jurisch and
• Gareth E. Arnott

Beilstein J. Org. Chem. 2019, 15, 1996–2002, doi:10.3762/bjoc.15.195

• functional group. General approach by Albrecht for MIC directed cyclometalation via C–H activation; M = Ru(II), Ir(III) or Rh(III). Concept of cyclometalated calix[4]arene target. High-resolution mass spectrum (ESI+) of putative ruthenacycle calix[4]arene 13. Synthesis of model mesoionic carbene 5. Attempted

Synthesis and anion binding properties of phthalimide-containing corona[6]arenes

• Meng-Di Gu,
• Yao Lu and
• Mei-Xiang Wang

Beilstein J. Org. Chem. 2019, 15, 1976–1983, doi:10.3762/bjoc.15.193

• investigate their anion binding behaviour. Taking compound 3a as a representative, we examined the interaction of macrocycles 3 with anions of tetra-n-butylammonium salts by means of electron spray ionization (ESI) mass spectrometry. It was found that the mass spectra of mixed samples of 3a with n-Bu4NX gave

Complexation of 2,6-helic[6]arene and its derivatives with 1,1′-dimethyl-4,4′-bipyridinium salts and protonated 4,4'-bipyridinium salts: an acid–base controllable complexation

• Jing Li,
• Qiang Shi,
• Ying Han and
• Chuan-Feng Chen

Beilstein J. Org. Chem. 2019, 15, 1795–1804, doi:10.3762/bjoc.15.173

• -polar solvent, acetone hampers or competes the intermolecular non-covalent interactions between the hosts and the guests, and thus resulted in a decrease of the host–guest complexation. ESIMS studies of the formation of host–guest complexes The electrospray ionization (ESI) mass spectra also confirmed

Synthesis, photophysical and electrochemical properties of pyridine, pyrazine and triazine-based (D–π–)₂A fluorescent dyes

• Keiichi Imato,
• Toshiaki Enoki,
• Koji Uenaka and
• Yousuke Ooyama

Beilstein J. Org. Chem. 2019, 15, 1712–1721, doi:10.3762/bjoc.15.167

• , 124.50, 124.79, 129.58, 130.62, 133.57, 139.41, 141.56, 142.95, 147.31, 148.55, 153.55, 167.62 ppm (one aromatic carbon signal was not observed due to overlapping resonances); HRMS–ESI (m/z): [M + H] + calcd. for C67H56N7S2, 1022.40331; found, 1022.40344. Chemical structures of the (D–π–)2A fluorescent

Synthesis, enantioseparation and photophysical properties of planar-chiral pillar[5]arene derivatives bearing fluorophore fragments

• Guojuan Li,
• Chunying Fan,
• Guo Cheng,
• Wanhua Wu and
• Cheng Yang

Beilstein J. Org. Chem. 2019, 15, 1601–1611, doi:10.3762/bjoc.15.164

• TMS as an internal standard. Due to the poor solubility, NMR spectra of P5A-DPA were recorded at room temperature on a Bruker AMX-600 spectrometer (operating at 600 MHz for 1H NMR and 151 MHz 13C NMR) in CDCl3. High-resolution mass spectra (HRMS) were measured using a Waters-Q-TOF Premiers (ESI

Synthesis and conformational preferences of short analogues of antifreeze glycopeptides (AFGP)

• Małgorzata Urbańczyk,
• Michał Jewgiński,
• Joanna Krzciuk-Gula,
• Jerzy Góra,
• Rafał Latajka and
• Norbert Sewald

Beilstein J. Org. Chem. 2019, 15, 1581–1591, doi:10.3762/bjoc.15.162

• purified by preparative RP-HPLC and identified by Accurate Mass Measurements performed on Agilent Techn. 6220 ToF LCMS; ionisation method: ESI. Ac-ʟ-Ala-ʟ-Thr(α-ᴅ-GalNAc)-ʟ-Ala-NH-Me (1) (27.7 mg, 79.0%); C21H37N5O10; exact mass: 519.25 g/mol; ESIMS: [M + H]+ 520.2618; 1H NMR (600 MHz, DMSO-d6) δ [ppm

An azobenzene container showing a definite folding – synthesis and structural investigation

• Abdulselam Adam,
• Saber Mehrparvar and
• Gebhard Haberhauer

Beilstein J. Org. Chem. 2019, 15, 1534–1544, doi:10.3762/bjoc.15.156

• , 1458, 1188, 1110, 761, 715 cm−1; UV–vis (CH3CN) λmax (log ε): 202 (4.69), 229 (4.69), 328 (4.50), 445 nm (2.99); HRMS (ESI–TOF) m/z: [M + H]+ calcd for C92H115N22O10, 1687.9161; found, 1687.9103; [M + Na]+ calcd for C92H114N22O10Na, 1709.8980; found, 1709.8929. Calculations. All calculations were

2,3-Dibutoxynaphthalene-based tetralactam macrocycles for recognizing precious metal chloride complexes

• Li-Li Wang,
• Yi-Kuan Tu,
• Huan Yao and
• Wei Jiang

Beilstein J. Org. Chem. 2019, 15, 1460–1467, doi:10.3762/bjoc.15.146

• isolated with yields of 22% and 19%, respectively. Electrospray ionization (ESI) mass spectra support the isolated products to be the [2 + 2] macrocycles (see Supporting Information File 1). As shown in Figure 1, the 1H NMR spectra are consistent with high-symmetry structures. There are slight differences

• supported by the ESI mass spectrum (Figure 4). The peak at m/z 1257.3140 was assigned to AuCl4−@1. The experimental isotopic pattern is consistent with the calculated one. In addition, precious metal chloride complexes PdCl42− and PtCl42− with TBA+ as counter ion can be bound by 1 as well (Figures S3 and S4

• values for (TBA)2[PtCl4] and (TBA)2[PdCl4] were 189 ± 36 M−1 and 198 ± 15 M−1, respectively. It should be noted that PdCl42− is relatively labile at high concentrations and is in equilibrium with the palladate dimer (Pd2Cl62−) and chloride ions [32][39]. The formation of Pd2Cl62− was supported by an ESI

Fluorine-containing substituents: metabolism of the α,α-difluoroethyl thioether motif

• Andrea Rodil,
• Alexandra M. Z. Slawin,
• Nawaf Al-Maharik,
• Ren Tomita and
• David O’Hagan

Beilstein J. Org. Chem. 2019, 15, 1441–1447, doi:10.3762/bjoc.15.144

• , J = 8.6 Hz, 2H), 3.91 (s, 3H), 2.02 (t, J = 18.3 Hz, 3H); 19F NMR (471 MHz, chloroform-d) δF −97.3 (s); 13C NMR (126 MHz, chloroform-d) δC 165.2, 133.1, 122.9, 114.7, 55.8, 16.6 (t, J = 22.2 Hz); HMRS (ESI) m/z: [M + H]+ calcd for C9H11F2O3S, 236.0310; found, 236.0390; [M + Na]+ calcd, 259.0211

• ), 135.1 (s, C-Ar), 133.6 (t, J = 218.8 Hz, CF2), 129.3 (s, C-Ar), 128.8 (s, C-Ar), 128.5 (s, C-Ar), 128.1 (s, C-Ar), 127.5 (s, C-Ar), 126.8 (s, C-Ar), 121.0 (s, C-Ar), 111.7 (C-Ar, visible in HMBC), 16.5 (t, J = 22.1 Hz, CF2CH3); HRMS (ESI+) m/z: [M + H]+ calcd for C12H11OF2S, 241.0420; found, 241.0491

• accurate mass spectrometry. 19F{1H} and 13C{1H}) NMR spectra were recorded on Bruker Avance III 500 or Bruker Avance III 500 HD spectrometers (500 MHz 1H, 476 MHz 19F, 126 MHz 13C). High-resolution mass spectrometry was acquired using electrospray ionisation (ESI), on a ThermoFisher Excalibur Orbitrap

Selenophene-containing heterotriacenes by a C–Se coupling/cyclization reaction

• Pierre-Olivier Schwartz,
• Sebastian Förtsch,
• Astrid Vogt,
• Elena Mena-Osteritz and
• Peter Bäuerle

Beilstein J. Org. Chem. 2019, 15, 1379–1393, doi:10.3762/bjoc.15.138

• interfaced to an Apollo II Dual ESI/MALDI source. Single crystals were analysed on a Bruker SMART APEX-II CCD diffractometer (λ(Mo Kα)-radiation, graphite monochromator, ω and 4 scan mode) and corrected for absorption using the SADABS program [53]. The structures were solved by direct methods and refined by

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