Synthesis of Water Soluble Spin Labeled Glucose Derivatives as Potential NMR Contrast Enhancing Agents

Abstract

<jats:title>Abstract</jats:title><jats:p>Synthetic methodologies for the preparation of nitroxyl labeled derivatives of D -(+)-glucose, α -D -(+)-m ethylglycoside, 2-amino-2-deoxy-D -(+)-glucose, and D -(+)-glucuronic acid are presented. The spin labels in these compounds are attached variably at the 1, 2, 3, and 6 positions of the glucose framework. These new compounds, being water soluble and producing marked en­hancement of spin-lattice (T ,) and spin-spin (T2) proton relaxation in deionized water and human plasma have potential utility as contrast altering pharmaceuticals for magnetic resonance imaging and as spin probes in biomolecular research. These spin labeled carbohydrates may demonstrate in vivo biodistribution characteristics reflecting tissue-specific differences in glucose metabolism .</jats:p>

A numerical prediction of spin-lattice relaxation enhancement of water protons by paramagnetic metal ions and free radicals. A contribution to the basic principles of relaxometry in MRI

“…The methodical factors F ~ 1.07 of Abragam [39] and Wehrli [40], and F-1.2 of Bennett et al [41] present the best match with experimental results which were obtained at 10.7 MHz (0.251 T) and 23.5+1~ [15,16,18,19,27,28]. The factors F --2.4 [33], F = 2.02 [41] and the factor F = 2.7 derived in the present work tend to result, under these experimental conditions, in somewhat shorter relaxation times, while the larger factors F = 3.6 and F = 4.0 result in more severe underestimates.…”

“…It was experimentally found [15,28] that the longitudinal relaxation times (T1) of water protons in the presence of 10 mM mononitroxyl radicals at 10.7 MHz (0.251 T) and 23.5_+1~ were on the average around 290 ras, fluctuating with structure. Pure water itself under the chosen conditions hada relaxation time of 2150 ms [15,16,18,27,28]. In human plasma and blood in vitro the relaxation times of protons tended to be, on the average, shorter, fluctuating around 260 ms [15,18].…”

“…Pure water itself under the chosen conditions hada relaxation time of 2150 ms [15,16,18,27,28]. In human plasma and blood in vitro the relaxation times of protons tended to be, on the average, shorter, fluctuating around 260 ms [15,18]. In the presence of diradicals, disregarding the effect of exchange interactions because of lack of reliable data, the proton relaxation times fluctuated around 130 ms, agaln depending on structure.…”

“…Analogous relaxation effects can be achieved with radicals, i.e. with organic species possessing one or more [15,[18][19]21,24,28,29] odd electrons, although the detailed relaxation mechanisms induced by radicals and metal ions may not be identical. The va¡ factors to be considered in the longitudinal relaxation phenomena of water proton can be pictorially presented (Fig.1), and were, in part, mathematically expressed by Solomon and Bloembergen in their equation, and by other equations [23,[36][37][38][39][40][41].…”