Avance neo 500

All commercially available materials and reagents were used without purification unless otherwise indicated. Purification via column chromatography was performed using silica gel (200–300 mesh). The melting points of the target compounds 10a–10l and 14a–14n were determined using an x-5 micro melting point apparatus, which was uncorrected. The purity and characterization of the target compounds were established using a combination of high-performance liquid chromatography and NMR analytical techniques, and the purity was >95% for all test compounds. NMR spectra (500 MHz for ¹H NMR and 125 MHz for ¹³C NMR spectra) were recorded on a Bruker AVANCE NEO 500 instrument, and were to be determined in CDCl₃ or DMSO-d₆. Chemical shifts were reported in ppm relative to tetramethylsilane (0.00 ppm) or solvent peaks as the internal reference. Splitting patterns are indicated as follows: s, singlet; d, doublet; t, triplet; m, multiplet. Coupling constants (J values) are given in hertz (Hz). High resolution mass spectrometry was conducted using a UPLC G2-XS QTOF spectrometer (Waters) with the electrospray ionization Fourier transform ion cyclotron resonance technique. The NMR and HRMS spectra of compounds 10a–10l and 14a-14n are presented in Figures S3–S80.

NMR spectra were obtained at the Institut für Anorganische und Analytische Chemie (Universität Münster), using Bruker Avance Neo 500 and Bruker Avance III 400. All measurements were performed at room temperature unless otherwise specified. The ¹H-NMR and ¹³C-NMR chemical shifts (δ) of the signals are given in parts per million and are referenced to the residual proton signal in the deuterated solvent DCM-d₂ (¹H: 5.32 ppm/¹³C: 54.0 ppm) or DMSO-d₆ (¹H: 2.50 ppm/¹³C: 39.52 ppm). The signal multiplicities are abbreviated as follows: s, singlet; d, doublet; t, triplet; q, quartet; br, broad; m, multiplet.
Exact mass (EM) determination by mass spectrometry (MS) was carried out at the Organisch-Chemisches Institut (Universität Münster) using a LTQ Orbitap LTQ XL (Thermo-Fisher Scientific, Bremen, Germany) with electrospray ionization (ESI). MALDI-TOF mass spectra were taken on Autoflex Speed MALDI-TOF spectrometer with 2-[(2E)-3-(4-tert-butylphenyl)-2-methylprop-2-enylidene]malonitrile (DCTB) as the matrix.

The ¹³C nuclear magnetic resonance (¹³C-NMR) spectra were measured using a Bruker AVANCE NEO 500 spectrometer (Bruker Corporation, Zurich, Switzerland). The ¹³C-NMR samples were prepared by dissolving 300 µL of samples in 100 µL of acetone-d6. The spectra were recorded with a pulse angle of 90 degrees (12 µs) and a relaxation delay of 2 s. The spectra were taken at 150 MHz with 400 accumulated scans.

CH₂Cl₂ was dried by distillation over CaH₂, and n-hexane by distillation over Na, benzophenone and tetraglyme. For NMR, deuterated solvents were dried by adding 3 Å molecular sieves to freshly opened bottles. All dry solvents were stored over 3 Å molecular sieves in a glovebox. Pyridine was redistilled prior to use. All other chemicals were used without further purification. For all synthesis performed in a glovebox, glassware had been dried at 150 °C in an oven, or in vacuo, at least overnight. NMR spectra were recorded on a Bruker Avance Neo 500 MHz spectrometer equipped with a TXO cryogenic probe, or an Agilent MR-400 equipped with an OneNMR probe. Chemical shifts are reported on the δ scale (ppm), with the residual solvent signal as an internal reference; CD₂Cl₂ (δ_H 5.32, δ_C 53.84), CDCl₃ (δ_H 7.26, δ_C 77.16). Nitromethane (δ_N 0.0 ppm) was used as an external standard for ¹⁵N. To assign the ¹H NMR resonances chemical shift (δ), multiplicity, coupling constants (J Hz) and number of hydrogens were considered. 2D spectra (¹H,¹⁵N HMBC, ¹H,¹³C HSQC, ¹H,¹³C HMBC, TOCSY, and COSY) also aided correct assignment. Multiplicities are denoted as s (singlet), d (doublet), t (triplet), q (quartet), h (heptet), and m (multiplet). MestReNova 12.0.2. was used to process the NMR spectra.

The five powders were measured with a Bruker Avance NEO 500 wide bore system (Bruker BioSpin, Rheinstetten, Germany) solid state ¹³C–NMR spectrometer at the NMR center of the faculty of chemistry University of Vienna. A 4 mm triple resonance magic angle spinning (MAS) probe was used with a resonance frequency for ¹³C of 125.78 MHz, the MAS rotor spinning was set to 14 kHz. Cross polarization (CP) was achieved by a ramped contact pulse with a contact time of 2 ms. During acquisition ¹H was high power decoupled using SPINAL (Bruker BioSpin, Rheinstetten, Germany) with 64 phase permutations. The chemical shifts for ¹³C are reported in ppm and are referenced external to adamantane by setting the low field signal to 38.48 ppm. The data elaboration was done with the software Top-spin 4.0.6 (Bruker, Billerica, MA, USA) while the calculations of the theoretical chemical shifts were done with the software NMR-Predict developed by the University of Lausanne (Luc Patiny) and the University of del Valle (Julien Wist) [46 (link),47 (link),48 (link)].

Xylan (2.00 g), DCC (6.24 g), and DMAP (1.76 g) were dissolved in DMSO (80 mL). 4.31 g of Sa dissolved in DMSO (40 mL) was added dropwise, and then the mixture was stirred at room temperature (RT) for 24 h. Next, the resulting solution was added dropwise to 95% ethanol (2 L) under ice bath conditions, then the precipitate was collected by centrifugation (6000 g, 5 min) at 4 °C. Finally, the precipitate was resuspended in ethanol (30 mL) and dried in vacuum at 45 °C. Sxy was obtained as white oily solid.
Cap (359.35 mg), Sa (853.44 mg), DCC (680.89 mg), and DMAP (36.65 mg) were dissolved in dichloromethane (20 mL), stirring for 24 h at RT. Then the reaction mixture was filtered by filter paper, and the filtrate was washed and dried in vacuum. Scap was obtained as white powder.
Both compounds were strored at −20 °C until use. The structures of Sxy and Scap were confirmed via ¹H NMR (AVANCE NEO 500, Bruker, USA), and the Mw were measured through MALDI-TOF MS (ThermoFisher Scientific, AB SCIEX 5800, USA).