NMR Analysis of Organic Compounds

NMR experiments for the compounds were performed in acetone-d₆ or MeOH-d₄. NMR spectra were acquired on a Bruker Biospin (Billerica, MA) Avance 360 MHz instrument with a room-temperature probe or an Avance 500 MHz spectrometer equipped with a 5 mm Triple Resonance Inverse (TCI) ¹H/¹³C/¹⁵N cryoprobe with inverse geometry (proton coils closest to the sample). The central acetone or MeOH solvent peaks were used as the internal reference (δ_C 29.8 and δ_H 2.04 ppm for acetone; δ_C 49.0 and δ_H 3.30 ppm for MeOH). Typical standard Bruker implementations of the traditional suite of one-dimensional (1D; ¹H and ¹³C) and two-dimensional (2D) NMR experiments [multiplicity-edited 13C, Distortionless Enhancement by Polarization Transfer (DEPT-135), homonuclear COrrelation SpectroscopY (COSY), Heteronuclear Single-Quantum Coherence (HSQC), and Heteronuclear Multiple-Bond Correlation (HMBC)] were used to elucidate/validate the structures. A small exponential multiplication line-broadening value (0.1 Hz) and zero-filling to a processed spectrum size (SI) of 256 K datapoints were applied to see the clear splitting of A3, A5, and Aα peaks from the DDC moiety, as well as the glucoside 1′ peak.