Construction of Meldonium (3-(1,1,1-Trimethylhydrazin-1-ium-2-yl)propanoate) Crystals: An X-ray View

Protein NMR Spectroscopy at 150 kHz Magic‐Angle Spinning Continues To Improve Resolution and Mass Sensitivity

“…We investigated the homogeneous linewidth of NH and CH x protons of the organic drug molecule meldonium ( Figure 3E and F), for which proton spectra and their assignment are given in Figure 5A. [44] In contrast to the investigated protein amide protons, meldonium protons show a very different correlation between homogeneous linewidth and MAS frequency, with linear fit components c (2) = 13 � 5, 12 � 1, and 47 � 4 kHz 2 for NH, CH 3 , and CH 2 values, respectively ( Figure 3E), and with nonvanishing quadratic contributions c (3) (Tables 1 and S3) , thus indicating significantly stronger proton-proton couplings. Although the spectral lines are thus significantly broader than the protein NH resonances at all spinning frequencies, their width decreases even more spectacularly with increasing spinning frequency ( Figure 5A).…”

“…We note that in particular the CH 2 proton resonances are very broad and of relatively low amplitude compared to the 9 : 4 abundance of methyl to methylene protons, even at 150 kHz MAS. To verify that these broader lines are indeed caused by a stronger dipolar-coupling network, we calculated the coherent linewidths at this spinning frequency from the crystal structure [44] and the observed chemical shifts by using a second-moment approach. [35] We obtain homogeneous linewidths of 415 Hz for the CH 2 , 228 Hz for the CH 3 , and 398 Hz for the NH groups, thus indicating that the homogeneous line broadening is again the dominant contribution.…”