Arend Hoekstra

On the stereoselectivity of the reaction of [18F]acetylhypofluorite with glucals☆

Abstract The reaction of acetylhypofluorite with tri-O-acetyl- D -glucal results in products, besides the proposed 2-deoxy-2-fluoro-tetra-O-acetyl- D -glucose, formed by a trans- or a reversed-addition, as analysed by 1H-NMR. Consequently, the resulting end-product FDG (2-deoxy-2-fluoro- D -glucose) is contaminated with 15–20% of the corresponding mannose derivative. Reaction of acetylhypofluorite with D -glucal gives 2-deoxy-2-fluoro- D -mannose (FDM) as the main product, especially when this reaction is performed in acetic acid. A TLC-system was developed to separate FDG and FDM on monosodium-phosphate impregnated silica plates.

Manganese-52m for direct application: A new 52Fe/52mMn generator based on a hydroxamate resin

A new generator system has been developed using the 52Fe/52mMn parent-daughter pair. A polymeric hydroxamate resin is used for the fixation of 52Fe, and the short-lived positron-emitter 52mMn is eluted in physiological saline. Preliminary animal studies in rats gave similar results with respect to biodistribution as are obtained for [54Mn] manganous chloride.

N-succinyldesferrioxamine B: a potential radiopharmaceutical for assessing renal function

N-Succinyldesferrioxamine B was found to be cleared very fast by the kidneys. Since this compound can strongly chelate several metals, including the generator-produced isotopes 113mIn and 68Ga, 67Ga-N-succinyldesferrioxamine B (SDF) was tested as a substitute for 131I-o-iodohippuric acid (OIH) in the measurement of renal tubular secretion. In rats both compounds showed similar biodistribution patterns with a greater excretion rate of SDF. In rabbits, however, the excretion rate of OIH was superior to that of SDF. Inhibition of tubular secretion by probenecid was nearly ineffective in the renal clearance of both OIH and SDF.

A simplified synthesis of 18F-labelled cytosine- and uracil-nucleosides

Abstract 18 F-labelled cytosine- and uracil- nucleosides are synthesized starting from their unprotected parent nucleosides by reaction with acetylhypofluorite in acetic acid in an overall radiochemical yield of 20 and 30% respectively.

Reaction of acetyl hypofluorite with aromatic mercury compounds: a new selective fluorination method

Aromatic fluorine compounds are prepared in acetic acid from the corresponding mercury compounds and acetyl hypofluorite.

Synthesis and tumour-localizing properties of [18F]-5-fluorocytosine-arabinoside and [18F]-5-fluorocyclocytidine.

Abstract[18F]-5-fluorocytosine-arabinoside (2) and [18F]-5-fluorocyclocytidine (4) were prepared by reaction of [18F]-acetylhypofluorite with cytosine-arabinoside (1) or cyclocytidine (3) in acetic acid and were isolated in an overall radiochemical yield of 20% and 9%, respectively. The biodistribution of both radiopharmaceuticals was determined in melanoma bearing Syrian golden hamsters. It was found that 2 is a good tumour-localizing agent for pigmented and non-pigmented Greene melanoma.

Evaluation of the renal scanning agent N-succinyldesferrioxamine B in dogs

The mechanism of the excretion of 67Ga-N-succinyldesferrioxamine B (SDF) was investigated in five healthy dogs. Comparison of the SDF clearance rates for whole blood and plasma as well as SDF renograms with those of 131I-o-iodohippuric acid (OIH) and 111In-diethy-lenetriamine-pentaacetic acid (DTPA) revealed that SDF is cleared by glomerular filtration and not by an active tubular transport mechanism.

On the mechanism of gallium accumulation in tumours. Isolation of N-hydroxypeptides

With the use of A SEP-PAK Alumina N cartridge, peptide fractions containing the hydroxamate moiety have been isolated from tumour-tissue homogenate. It is therefore postulated that N-hydroxypeptides might play a role in the accumulation of gallium-67 in tumours. The biodistribution of several 67Ga-labelled hydroxamate peptide fractions is determined. Although their biodistribution differs from that of 67Ga-citrate no enhancement in tumour accumulation is observed indicating that they do not act like tumour-specific siderophores.