Synthesis and characterization of water-soluble C₆₀–peptide conjugates

• Yue Ma,
• Lorenzo Persi and
• Yoko Yamakoshi

Beilstein J. Org. Chem. 2024, 20, 777–786, doi:10.3762/bjoc.20.71

• a charged state of 3+ (Figure S2, Supporting Information File 1), C60–oligo-Glu (5b) was confirmed by HRMS–MALDI (Figure S11, Supporting Information File 1) due to insolubility in the acidic eluent generally used for HRESIMS (a mixture of MeOH and water containing 0.1% formic acid). C60–oligo-Arg

• . C60–oligo-Glu (5b) was obtained in a yield of 36% for the total peptide synthesis and characterized by HRMS–MALDI. HRMS–MALDI (m/z): [M + H]+ calcd for C125H96N13O36, 2354.6075; found, 2354.6008. C60–oligo-Arg (5c) was obtained in a crude yield of 66% for the total peptide synthesis and characterized

Synthesis of new representatives of A₃B-type carboranylporphyrins based on meso-tetra(pentafluorophenyl)porphyrin transformations

• Victoria M. Alpatova,
• Evgeny G. Rys,
• Elena G. Kononova and
• Valentina A. Ol'shevskaya

Beilstein J. Org. Chem. 2024, 20, 767–776, doi:10.3762/bjoc.20.70

• carborane A3B-porphyrin were also synthesized based on the amino-substituted A3B-porphyrin. The structures of the prepared carboranylporphyrins were determined by UV–vis, IR, 1H, 19F, 11B NMR spectroscopic data and MALDI mass spectrometry. Keywords: bioconjugation; carboranes; fluorine; porphyrin; SNAr

• functionality was supported by the design of conjugates containing maleimide and biotin substituents. The structures of prepared carboranylporphyrins were determined by UV–vis, IR, 1H 19F, 11B NMR spectroscopic data and MALDI mass spectrometry. Synthesis of porphyrins 2 and 3. Synthesis of carborane

Enhanced reactivity of Li⁺@C₆₀ toward thermal [2 + 2] cycloaddition by encapsulated Li⁺ Lewis acid

• Hiroshi Ueno,
• Yu Yamazaki,
• Hiroshi Okada,
• Fuminori Misaizu,
• Ken Kokubo and
• Hidehiro Sakurai

Beilstein J. Org. Chem. 2024, 20, 653–660, doi:10.3762/bjoc.20.58

• , external standard), and carbon of the solvent for 13C (53.84 ppm, CD2Cl2). High-resolution matrix-assisted laser desorption ionization (HR-MALDI) mass spectra were obtained on a Bruker solariX 12T mass spectrometer with dithranol as a matrix. UV–vis absorption spectra were measured on a JASCO V-670 and a

• , 146.12, 146.66, 146.72, 147.48, 147.85, 153.12, 153.33, 156.27, 156.48, 160.24; 7Li NMR (155 MHz, CD2Cl2) δ −12.4; HRMS–MALDI–TOF, positive ion mode, dithranol (m/z): [M]+ calcd for C70H12OLi, 875.10427; found, 875.10431. Synthesis of Li+@C60{(4-MeOC6H4)CH=CH2} TFSI− (5b) To 2.5 mL of a chlorobenzene

• , 145.02, 145.14, 145.22, 145.29, 145.43, 145.57, 145.61, 145.63, 145.67, 145.72, 145.77, 145.82, 145.90, 146.51, 146.69, 146.85, 153.12, 155.45, 155.75, 155.85, 159.84; 7Li NMR (272 MHz, CD2Cl2) δ −13.3; HRMS–MALDI–TOF, positive ion mode, dithranol (m/z): [M]+ calcd for C69H10OLi, 861.08862; found

Synthesis of the 3’-O-sulfated TF antigen with a TEG-N₃ linker for glycodendrimersomes preparation to study lectin binding

• Mark Reihill,
• Hanyue Ma,
• Dennis Bengtsson and
• Stefan Oscarson

Beilstein J. Org. Chem. 2024, 20, 173–180, doi:10.3762/bjoc.20.17

• treated with 1 M Bu4NF/THF and after 2 hours, full consumption of the starting material was observed by TLC. However, MALDI–TOF mass spectrometry (super-DHB matrix) revealed that only the Troc group had been removed, with the DTBS substituent proving to be stable under these conditions. Addition of a

• electrospray ionisation (ESI) in positive mode. MALDI–TOF mass spectrometry data were recorded on a Scientific Analysis Instruments MALDI–TOF mass spectrometer in reflectron mode for oligosaccharides and in linear mode for glycoconjugates. Samples were prepared by pre-mixing 1 µL of a solution containing the

Multi-redox indenofluorene chromophores incorporating dithiafulvene donor and ene/enediyne acceptor units

• Christina Schøttler,
• Kasper Lund-Rasmussen,
• Line Broløs,
• Philip Vinterberg,
• Ema Bazikova,
• Viktor B. R. Pedersen and
• Mogens Brøndsted Nielsen

Beilstein J. Org. Chem. 2024, 20, 59–73, doi:10.3762/bjoc.20.8

• synthesis of compound 23 (Scheme 4). A compound that may tentatively be assigned to 28 was observed by MALDI–MS analysis of the reaction mixture, but less than needed for an NMR sample was isolated. Furthermore, the isolated compound proved quite insoluble in all investigated deuterated solvents, and

• are referenced to the ppm scale and coupling constants are expressed in Hertz (Hz). HRMS analysis was performed on a Bruker SolariX XR MALDI-FT-ICR instrument with dithranol as matrix. Melting points are not corrected. UV–vis absorption spectroscopy UV–vis absorption spectra were recorded on a Varian

• , 121.0, 123.4, 121.6, 120.0, 119.7, 119.6, 115.7, 114.5, 52.7, 52.6, 35.4, 35.2, 31.9, 31.4, 21.8 ppm; five sp2 signals missing, presumably due to overlap. HRMS (MALDI+, FT-ICR, dithranol, m/z) [M + H+] calcd for C40H38NO3S3+, 676.2008; found, 676.2019. Compound 13 A solution of 4 (62.0 mg, 92.0 μmol

Controlling the reactivity of La@C₈₂ by reduction: reaction of the La@C₈₂ anion with alkyl halide with high regioselectivity

• Yutaka Maeda,
• Saeka Akita,
• Mitsuaki Suzuki,
• Michio Yamada,
• Takeshi Akasaka,
• Kaoru Kobayashi and
• Shigeru Nagase

Beilstein J. Org. Chem. 2023, 19, 1858–1866, doi:10.3762/bjoc.19.138

• -electron reduction of Gd@C2v-C82 for the addition reaction to occur at room temperature [22]. Supporting Information File 1, Figure S1 depicts the three HPLC separation steps including recycling for the isolation. The matrix-assisted laser desorption/ionization time-of-flight (MALDI–TOF) mass spectra of 2a

• were calculated using the Gaussian 03 program with DFT at the B3LYP/3-21G for C and H [33], and the LanL2DZ basis set and effective core potential (ECP) for La [29][32]. La@C2v-C82(CH2C6H4CH3) (2a): vis–NIR (CS2): λmax = 572, 741, 1304 nm; MALDI–TOF MS (m/z): [MH]+ calcd for LaC90H9, 1228.98; found

• , 1229.04. La@C2v-C82(CH2C6H4CH3) (3a): vis–NIR (CS2): λmax = 560, 851, 991, 1271 nm; MALDI–TOF MS (m/z): [MH]+ calcd for LaC90H9, 1228.98; found, 1228.99. La@C2v-C82(CH2C6H4CH3) (4a): vis–NIR (CS2): λmax = 525, 986, 1410 nm; MALDI–TOF MS (m/z): [MH]+ calcd for LaC90H9, 1228.98; found, 1229.15. La@C2v-C82

A deep-red fluorophore based on naphthothiadiazole as emitter with hybridized local and charge transfer and ambipolar transporting properties for electroluminescent devices

• Suangsiri Arunlimsawat,
• Patteera Funchien,
• Pongsakorn Chasing,
• Atthapon Saenubol,
• Taweesak Sudyoadsuk and
• Vinich Promarak

Beilstein J. Org. Chem. 2023, 19, 1664–1676, doi:10.3762/bjoc.19.122

• MALDI-TOF-MS techniques. To examine the electronic properties of D–A TPECNz, density functional theory (DFT) calculations at the B3LYP level of theory with the 6-31G(d,p) basis set were performed. It has been previously reported that the twist angle of the D–A segment has a significant role in

• performed using either a Bruker LC-Quadrupole-Time-of Flight tandem mass spectrometer or a Bruker Autoflex MALDI-TOF mass spectrometer. UV–vis spectra were recorded using a Perkin Elmer Lambda 1050 UV–vis–NIR spectrometer. Luminescence emission spectra and lifetimes were analyzed using an Edinburgh

• , 129.14, 128.16, 127.87, 127.81, 127.72, 127.43, 126.78, 126.71, 126.63, 126.22, 126.17, 123.56, 123.35, 123.21, 120.53, 120.11, 110.03, 109.89; HMRS–MALDI–TOF (m/z): [M]+ calcd for C86H56N4S, 1176.4226; found, 1176.4221. a) The optimized structure and HOMO/LUMO distributions calculated by B3LYP/6-31G(d,p

The effect of dark states on the intersystem crossing and thermally activated delayed fluorescence of naphthalimide-phenothiazine dyads

• Liyuan Cao,
• Xi Liu,
• Xue Zhang,
• Jianzhang Zhao,
• Fabiao Yu and
• Yan Wan

Beilstein J. Org. Chem. 2023, 19, 1028–1046, doi:10.3762/bjoc.19.79

• , 130.6, 130.4, 130.3, 123.8, 123.6, 123.1, 116.8, 116.7, 116.5; HRMS–MALDI (m/z): [M + H]+ calcd for C30H17FN2O3S, 505.0944; found, 505.0973. Electrochemical studies The cyclic voltammetry curves were recorded with a CHI610D electrochemical workstation (CHI instruments, Inc., Shanghai, China) in N2

Eschenmoser coupling reactions starting from primary thioamides. When do they work and when not?

• Lukáš Marek,
• Jiří Váňa,
• Jan Svoboda and
• Jiří Hanusek

Beilstein J. Org. Chem. 2023, 19, 808–819, doi:10.3762/bjoc.19.61

• solutions (DMSO-d6, MeOD-d4, D2O), it was impossible to measure its NMR spectra and the only characterization involves MALDI–MS, IR, and melting point. The salt 6a was then treated in various solvents with or without additive (thiophile, base/acid) to give diverse products of cyclization (8a or 8a-Me), ECR

• recorded on a Bruker Avance III 400 MHz or on a Bruker Ascend 500 MHz instrument. Chemical shifts (δ) are referenced to TMS (δ = 0) or solvent residual peaks δ(CDCl3) = 7.24 ppm (1H) and 77.0 ppm (13C), δ(DMSO-d6) = 2.50 ppm (1H) and 39.6 ppm (13C). High-resolution mass spectra were recorded on a MALDI LTQ

• Orbitrap XL equipped with nitrogen UV laser (337 nm, 60 Hz, 8–20 μJ) in positive ion mode. For the CID experiment using the linear trap quadrupole (LTQ) helium was used as the collision gas and 2,5-dihydroxybenzoic acid (DHB) or (2-methylprop-2-en-1-yliden)malononitrile (DCTB) as the MALDI matrix

Phenanthridine–pyrene conjugates as fluorescent probes for DNA/RNA and an inactive mutant of dipeptidyl peptidase enzyme

• Josipa Matić,
• Tana Tandarić,
• Marijana Radić Stojković,
• Filip Šupljika,
• Zrinka Karačić,
• Ana Tomašić Paić,
• Lucija Horvat,
• Robert Vianello and
• Lidija-Marija Tumir

Beilstein J. Org. Chem. 2023, 19, 550–565, doi:10.3762/bjoc.19.40

• (multiplet). High-resolution mass spectra (HRMS) were obtained using a MALDI–TOF/TOF mass spectrometer 4800 Plus MALDI TOF/TOF analyzer (Applied Biosystems Inc., Foster City, CA, USA). The electronic absorption spectra of newly prepared compounds, UV–vis titration and thermal melting experiments were

Investigation of cationic ring-opening polymerization of 2-oxazolines in the “green” solvent dihydrolevoglucosenone

• Solomiia Borova and
• Robert Luxenhofer

Beilstein J. Org. Chem. 2023, 19, 217–230, doi:10.3762/bjoc.19.21

• ). Obtained data were processed with Win-GPC software. Matrix-assisted laser desorption/ionization time-of-flight mass spectra (MALDI-TOF MS) were recorded on an Autoflex II (Bruker Daltonics, Bremen, Germany) using an N2 laser (λ = 337 nm). All spectra were recorded in positive reflector mode. Detection was

• obtained after precipitation from cold Et2O and lyophilization were analyzed by MALDI-TOF mass spectrometry (Figure 3, Figure 4, and Figures S9–S11 in Supporting Information File 1). The resulting MALDI-TOF mass spectra clearly confirm the presence of the desired polymer. The mass difference (Δm/z) between

• distributions (ε) and (δ) of low intensity can be attributed to a methyl-initiated and proton-initiated PEtOx formed after termination at position C2 with the final fragmentation of the formed ester group during the MALDI-TOF MS assay carrying Na+ and H+ ions, respectively. It is well known that water and

A study of the DIBAL-promoted selective debenzylation of α-cyclodextrin protected with two different benzyl groups

• Naser-Abdul Yousefi,
• Morten L. Zimmermann and
• Mikael Bols

Beilstein J. Org. Chem. 2022, 18, 1553–1559, doi:10.3762/bjoc.18.165

• in Table 1. Firstly, reaction with DIBAL in toluene at 0.3 M concentration and at 50 °C gave after 24 h almost complete conversion of the starting material to a symmetrical compound 8 that according to MALDI–TOF MS has lost two DCB groups and not any benzyl group. The compound was analyzed with 1H

• ), 75.66 (ArCH2), 72.93 (ArCH2), 71.62 (C-5), 69.94 (ArCH2) 69.91 (C-6) ppm; HRMS–MALDI+ (m/z): [M + Na]+ calcd for C162H156Cl12O30Na+, 3030.6782; found, 3030.67364. General procedure for the reactions of 7 with DIBAL: A sample of compound 7 (65 mg, 22 μmol) was dissolved in 0 to 6 mL anhydrous toluene in

• –MALDI (m/z): for 8 [M + Na]+ calcd for C141H142Cl8O30Na+, 2712.7431; found: 2712.74127. for 9 [M + K]+ calcd for C162H156Cl12O30K+, 2638.6701; found, 2638.71363. 6B,C,E,F-Tetra-O-(2,4-dichlorobenzyl)-2A–F,3B,C,E,F-dodeca-O-benzyl-α-cyclodextrin (10): Compound 7 (59 mg, 20 μmol) was dissolved in

Naphthalimide-phenothiazine dyads: effect of conformational flexibility and matching of the energy of the charge-transfer state and the localized triplet excited state on the thermally activated delayed fluorescence

• Kaiyue Ye,
• Liyuan Cao,
• Davita M. E. van Raamsdonk,
• Zhijia Wang,
• Jianzhang Zhao,
• Daniel Escudero and
• Denis Jacquemin

Beilstein J. Org. Chem. 2022, 18, 1435–1453, doi:10.3762/bjoc.18.149

• , 126.37, 125.31, 125.01, 124.16, 122.85, 119.77, 44.36, 37.97, 30.77, 29.70, 28.71, 24.08, 23.10, 10.66; HRMS–MALDI (m/z): [M + H]+ calcd for C32H30N2O2S, 506.2028; found, 506.2023. Synthesis of NI-PTZ-O Compound NI-PTZ-O was synthesized in a manner similar to [59]. Compound NI-PTZ (200 mg, 0.4 mmol) was

• , 20.81, 10.66; HRMS–MALDI (m/z): [M + H]+ calcd for C32H30N2O3S, 522.1977; found, 523.2050. Synthesis of NI-PTZ2 Compound NI-PTZ2 was synthesized in a manner similar to [21]. Under N2 atmosphere, compound 1 (190.0 mg, 0.409 mmol), phenothiazine (294.5 mg, 1.478 mmol), Pd(OAc)2 (36 mg, 0.160 mmol), and

• ); 13C NMR (CDCl3, 125 MHz) δ 163.94, 142.79, 135.00, 127.96, 127.82, 126.96, 126.23, 124.62, 123.50, 121.13, 44.52, 37.95, 30.75, 29.70, 28.72, 24.06, 23.10, 10.66; HRMS–MALDI (m/z): [M + H]+ calcd for C44H37N3O2S2, 703.2327; found, 703.2322. Synthesis of NI-Ph-PTZ Compound NI-Ph-PTZ was synthesized in

Synthesis of protected precursors of chitin oligosaccharides by electrochemical polyglycosylation of thioglycosides

• Md Azadur Rahman,
• Kana Kuroda,
• Hirofumi Endo,
• Norihiko Sasaki,
• Tomoaki Hamada,
• Hiraku Sakai and
• Toshiki Nokami

Beilstein J. Org. Chem. 2022, 18, 1133–1139, doi:10.3762/bjoc.18.117

• obtained at T1 = −60 °C and T2 = −30 °C, although heptasaccharide 7a was not produced. MALDI–TOF MS spectra indicated the formation of byproducts derived from longer oligosaccharides at T1 = −30 °C and T2 = −30 °C (Figure 5). The relative intensity of the molecular ion peaks of hydroxy-substituted sugars

• (T2) on the yield of oligosaccharides. Influence of temperatures of anodic oxidation (T1) and glycosylation (T2). MALDI–TOF MS spectra of oligosaccharides. Proposed structures of byproducts of electrochemical polyglycosylation. Proposed mechanisms of electrochemical polyglycosylation. Oxidative

Introducing a new 7-ring fused diindenone-dithieno[3,2-b:2',3'-d]thiophene unit as a promising component for organic semiconductor materials

• Valentin H. K. Fell,
• Joseph Cameron,
• Alexander L. Kanibolotsky,
• Eman J. Hussien and
• Peter J. Skabara

Beilstein J. Org. Chem. 2022, 18, 944–955, doi:10.3762/bjoc.18.94

• refluxed overnight [43]. The result was a dark violet/black material, which was not soluble in common organic solvents, thereby preventing NMR spectroscopy. Also, sublimation failed. However, the mass could be measured with MALDI mass spectrometry, and microanalysis results matched the theoretical values

Thiophene/selenophene-based S-shaped double helicenes: regioselective synthesis and structures

• Mengjie Wang,
• Lanping Dang,
• Wan Xu,
• Zhiying Ma,
• Liuliu Shao,
• Guangxia Wang,
• Chunli Li and
• Hua Wang

Beilstein J. Org. Chem. 2022, 18, 809–817, doi:10.3762/bjoc.18.81

• obtained using an FTIR instrument. MS analysis was carried out on mass spectrometers equipped with EI (70 eV). HRMS analysis was carried out on a mass spectrometer equipped with DART-FT-ICR and MALDI-TOF-CHCA. Melting-point determination was taken on a Melt-Temp apparatus and mp are uncorrected. The X-ray

• ); HRMS-MALDI (m/z): [M]+ calcd for C32H30S6Si2, 662.0216; found, 662.0205. 1,3-Bis(2-(5-(trimethylsilyl)diselenopheno[2,3-b:3',2'-d]thiophen-2-yl)vinyl)benzene (5b) was synthesized according to the procedure described for compound 5a. 5b: yellow solid in yield of 64% (46.2 mg); mp > 300 °C; 1H NMR (300

• , 141.6, 141.4, 141.3, 141.1, 135.0, 133.4, 130.6, 129.8, 129.0, 128.5, 127.53, 127.46, 127.3, 127.0, 126.7, 126.4, 124.3, 123.7, 121.5, 119. 7, 0.0, −0.4; IR (KBr): 3045, 2952, 2860, 1645, 1487, 1410, 972, 837 cm−1; EIMS (70 eV) m/z: [M]+ 657.87 (30); HRMS-MALDI (m/z): [M]+ calcd for C32H26S6Si2 657.9897

Synthesis of a new water-soluble hexacarboxylated tribenzotriquinacene derivative and its competitive host–guest interaction for drug delivery

• Man-Ping Li,
• Nan Yang and
• Wen-Rong Xu

Beilstein J. Org. Chem. 2022, 18, 539–548, doi:10.3762/bjoc.18.56

• recorded using either the ultrafleXtreme MALDI-TOF mass spectrometer (Bruker) with α-cyano-4-hydroxycinnamic acid (HCCA) as a matrix, or by electrospray ionization (ESI) on a Waters G2-XS QTOF instrument connected to a Waters H-class UPLC equipped with a Waters BEH C18 column using an eluent consisting of

• , 3H); 13C NMR (100 MHz, DMSO-d6, 25 °C) δ 168.55, 148.01, 143.23, 137.64, 126.25, 110.44, 62.71, 62.63, 62.26, 50.89, 27.58; MALDI-TOF MS (m/z) [M + H]+ calcd for C53H49N18O18, 1225.3467; found, 1225.3449 (Δ = −1.5 ppm). Synthesis of compound TBTQ-CB6. Compound 3 (0.27 g, 0.22 mmol) was dissolved in a

• solid (0.28 g, 97%). Mp 198.2–199.4 °C; 1H NMR (400 MHz, D2O, 25 °C) δ 7.89 (s, 6H), 7.21 (s, 6H), 5.25 (s, 12H), 4.97, 4.91 (ABq, J = 17.2 Hz, 12H), 4.31 (s, 3H), 1.57 (s, 3H); 13C NMR (100 MHz, D2O, 25 °C) δ 172.58, 147.37, 143.07, 138.51, 126.22, 110.74, 63.11, 62.15, 61.82, 52.77, 24.69; MALDI-TOF

Peptide stapling by late-stage Suzuki–Miyaura cross-coupling

• Hendrik Gruß,
• Rebecca C. Feiner,
• Ridhiwan Mseya,
• David C. Schröder,
• Michał Jewgiński,
• Kristian M. Müller,
• Rafał Latajka,
• Antoine Marion and
• Norbert Sewald

Beilstein J. Org. Chem. 2022, 18, 1–12, doi:10.3762/bjoc.18.1

• macrocyclisation product, which was confirmed by MALDI-ToF-MS of the crude reaction mixture after test cleavage (see Supporting Information File 1, Figure S1). However, deboronation and dehalogenation were observed as side reactions to some extent as well as oxidation, most likely of methionine (Met) [79]. The

Recent advances in the application of isoindigo derivatives in materials chemistry

• Andrei V. Bogdanov and
• Vladimir F. Mironov

Beilstein J. Org. Chem. 2021, 17, 1533–1564, doi:10.3762/bjoc.17.111

• photoelectrochemical reduction of water, as matrix for MALDI spectrometry and in photothermal cancer therapy are also shown. Data published over the past 5 years, including works published at the beginning of 2021, are given. Keywords: isoindigo; OFET; photoactive polymers; photovoltaics; solar cells; Introduction

• matrix (in positive and negative modes), which is a rarity for the MALDI method. The detection limits were below 164 pmol for reserpine and below 245 pmol for cholic acid. More recently, another new application of polyisoindigos was discovered as a new conductive binder inside electrodes containing

A new glance at the chemosphere of macroalgal–bacterial interactions: In situ profiling of metabolites in symbiosis by mass spectrometry

• Marine Vallet,
• Filip Kaftan,
• Veit Grabe,
• Fatemeh Ghaderiardakani,
• Simona Fenizia,
• Aleš Svatoš,
• Georg Pohnert and
• Thomas Wichard

Beilstein J. Org. Chem. 2021, 17, 1313–1322, doi:10.3762/bjoc.17.91

• algal surfaces and their metabolic activities can be monitored in situ or using an imprinting method by desorption electrospray ionisation mass spectrometry [17][18]. In U. mutabilis gametophytes, matrix-assisted laser desorption ionisation mass spectrometry imaging (MALDI-MSI) was used to identify cell

• differentiation markers [19]. However, there has yet to be a thorough investigation of associated-mutualistic bacteria. MALDI-MSI has been shown to have high sensitivity and spatial resolution at the microscale in plant tissues, plankton, and other microbes [20][21]. The application of a MALDI matrix to a sample

• is an important part of the MALDI-MSI experiment. MALDI-MS can be used to identify proteins and metabolic signatures [22][23][24] from bacteria and microalgae, as well as biofilms [25]. The primary function of the applied matrix is to improve the quality of the MS spectra, particularly the signal

Structural effects of meso-halogenation on porphyrins

• Keith J. Flanagan,
• Maximilian Paradiz Dominguez,
• Zoi Melissari,
• Hans-Georg Eckhardt,
• René M. Williams,
• Dáire Gibbons,
• Caroline Prior,
• Gemma M. Locke,
• Alina Meindl,
• Aoife A. Ryan and
• Mathias O. Senge

Beilstein J. Org. Chem. 2021, 17, 1149–1170, doi:10.3762/bjoc.17.88

• were measured with a Stuart SP-10 melting point apparatus. A Bruker Advance III 400 MHz spectrometer was employed for 1H (400.13 MHz), and 13C (100.61 MHz) NMR spectra. All NMR experiments were performed at room temperature. Mass spectrometry analysis was performed with a Q-Tof Premier Waters MALDI

• quadrupole time-of-flight (Q-TOF) mass spectrometer equipped with Z-spray electrospray ionization (ESI) and matrix-assisted laser desorption ionization (MALDI) sources either in a positive or negative mode with DCTB (trans-2-[3-(4-tert-butylphenyl)-2-methyl-2-propenylidene]malononitrile) as the matrix. UV

• , 134.8, 137.7, 138.9, 142.1 ppm; UV–vis (DCM) λmax (log ε) 420 (5.30), 519 (3.91), 555 (3.68), 596 (3.38) nm; HRMS−MALDI (m/z): [M+] calcd for C40H29ClN4, 600.2081; found, 600.2050. Note on synthesis of chloro derivatives of porphyrins The reaction entailed an attempt to prepare a meso–meso linked

Enhanced target cell specificity and uptake of lipid nanoparticles using RNA aptamers and peptides

• Roslyn M. Ray,
• Anders Højgaard Hansen,
• Maria Taskova,
• Bernhard Jandl,
• Jonas Hansen,
• Citra Soemardy,
• Kevin V. Morris and
• Kira Astakhova

Beilstein J. Org. Chem. 2021, 17, 891–907, doi:10.3762/bjoc.17.75

• chromatography utilizing gradient elution (2–50% MeOH in DCM). The desired modified T7 peptide was characterized via MALDI-TOF spectrometry (Bruker, MA, Supporting Information File 1, Figure S1B) and isolated as a colorless powder (9 mg, 6 μmol, 6% yield). MS (m/z): [M + H]+ calcd, 1455.00; found, 1455.20. The

• crude Tat–lipid conjugate was precipitated from DMF as a white power and used without further purification. The modified Tat peptide was characterized via MALDI–TOF spectrometry (Supporting Information File 1, Figure S1C, 31 mg, 14 μmol, 15% yield). MS (m/z): [M + H]+ calcd, 2121.48; found, 2121.17

Synthesis and properties of oligonucleotides modified with an N-methylguanidine-bridged nucleic acid (GuNA[Me]) bearing adenine, guanine, or 5-methylcytosine nucleobases

• Naohiro Horie,
• Takao Yamaguchi,
• Shinji Kumagai and
• Satoshi Obika

Beilstein J. Org. Chem. 2021, 17, 622–629, doi:10.3762/bjoc.17.54

• , CDCl3 (δ = 77.0 ppm) for 13C NMR, and 5% H3PO4 (δ = 0 ppm) for 31P NMR. Infrared (IR) spectra were recorded using a JASCO FT/IR-4200 spectrometer. The optical rotation was recorded using a JASCO P-2200 instrument. A MALDI–TOF mass spectrometer (SpiralTOF JMS-S3000) was used to measure the mass spectra

• , 128.84, 129.94, 130.01, 132.87, 133.31, 135.21, 135.47, 140.48, 144.26, 149.38, 150.80, 152.55, 158.52, 164.76; HRMS–MALDI (m/z): [M + Na]+ calcd for C43H42N8O7Na, 805.3069; found, 805.3063. (1R,3R,4R,7S)-5-(N'-Acetyl-N-methylcarbamimidoyl)-1-(4,4'-dimethoxytrityl)oxymethyl-3-(O6-diphenylcarbamoyl-N2

• , 127.90, 128.02, 129.18, 129.94, 129.99, 135.31, 135.52, 141.55, 144.34, 150.26, 151.60, 153.12, 156.07, 158.50, 162.61, 174.91; HRMS (MALDI) (m/z): [M + Na]+ calcd. for C53H53N9O9Na, 982.3858; found, 982.3856. (1R,3R,4R,7S)-5-(N'-Acetyl-N-methylcarbamimidoyl)-1-(4,4'-dimethoxytrityl)oxymethyl-3-(O6

Synthesis of (Z)-3-[amino(phenyl)methylidene]-1,3-dihydro-2H-indol-2-ones using an Eschenmoser coupling reaction

• Lukáš Marek,
• Lukáš Kolman,
• Jiří Váňa,
• Jan Svoboda and
• Jiří Hanusek

Beilstein J. Org. Chem. 2021, 17, 527–539, doi:10.3762/bjoc.17.47

• ) and 39.6 ppm (13C). High-resolution mass spectra were recorded on a MALDI LTQ Orbitrap XL equipped with a nitrogen UV laser (337 nm, 60 Hz, 8–20 μJ) in the positive ion mode. For the CID experiment using the linear trap quadrupole (LTQ) helium was used as the collision gas and 2,5-dihydroxybenzoic

• acid (DHB) or (2-methylprop-2-en-1-yliden)malononitrile (DCTB) as the MALDI matrix. Elemental analyses were performed on a Flash 2000 Organic Elemental Analyser (Thermofisher). For samples containing chlorine mercurimetric titration was used. IR spectra were recorded on a Nicolet iS50 equipped with an

The synthesis of chiral β-naphthyl-β-sulfanyl ketones via enantioselective sulfa-Michael reaction in the presence of a bifunctional cinchona/sulfonamide organocatalyst

• Deniz Tözendemir and
• Cihangir Tanyeli

Beilstein J. Org. Chem. 2021, 17, 494–503, doi:10.3762/bjoc.17.43

• by chiral HPLC chromatography using Agilent instrument. All new products were further analyzed by LC/MS–HRMS–TOF or MALDI–ESI–TOFMS. Synthesis of organocatalyst 5 A solution of quinineamine 2 (226.40 mg, 0.70 mmol) and triethylamine (107 μL, 0.77 mmol) in CH2Cl2 was added to a screw-capped reaction