PubMed · 8107793
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B D Gomperts. 1994-02-03. Adrenocentenary.. https://doi.org/10.1038/367405b0
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Periodic acid and its salts have been widely used for the quantitative oxidation of vic-diol containing compounds including carbohydrates and catecholamine drugs. The advantage of using a polymeric resin (periodate form) over free periodate ions is that the resin quantitatively retains both unconsumed periodate ions and the iodate ions produced in the oxidation and, hence, enables one to undertake further studies on the structural, synthetic or preparative work. The resin (periodate form) was found to be a clean and sensitive chromogenic reagent for the spectrophotometric determination of some catecholamine drugs. The calibration graphs of absorption versus concentration in the range studied (5-50 ppm) were linear.
Proton NMR measurements of the spectrum, second moment, spin-lattice relaxation time T1 and dipolar relaxation time T1D were carried out on polycrystalline L-adrenaline at 14 and 25 MHz between 55 and 400 K. Between 70 K and 250 K relaxation is dominated by C3 reorientation of the single methyl group in each molecule, characterized by an activation energy 8.3+/-0.3 kJ/mole. Below 70 K tunnelling assisted relaxation is significant, characterized by an excitation energy of 1.9+/-0.2 kJ/mole. Above 250 K an additional molecular motion becomes significant, with activation energy above 28 kJ/mole, attributed to conformational motion of the methylene group in the ethylamine side chain.