Prosthetic iodination methods for radiolabeling of carbonyl moieties

Thesis/Dissertation · Thu Jan 01 00:00:00 EST 1987

OSTI ID:6977623

Barakat, B M.A.

The demonstrable need for an indirect, prosthetic-group, radioiodination of carbonyl-containing biomolecules such as ketosteroids, carbohydrates, gangliosides, glycoproteins and aldehydo- and keto-drugs. This need has been addressed by developing a route to iodinated (radioiodination) aryl hydrazides which are subsequently condensed with carbonyl-containing moieties. This dissertation is directed at improving the utility of this reaction and at comparing the hydrolytic stability of the resulting hydrazones to that of similar tyramine imines, a type presently employed in indirect radioiodinations. The aryl carboxylic acid hydrazones were virtually inert to hydrolysis under simulated physiological conditions which caused imine bond rupture. Further improvements to this new prosthetic labeling method were sought in simplifying its two-step, acid-catalyzed cleavage of triazenooxadiazoles (the protected, pre-labeling form of the aryl carboxylic acid hydrazides) to the iodinated hydrazide. Synthetic procedures were explored which might yield non-conjugated aryl oxadiazoles--bearing methylenes inserted between the phenyl and the heterocyclic ring--in the expectation that these substances would be less stable and would hydrolyze in a single-acid-catalyzed step. Four synthetic pathways to amino (or nitro) aryl-methyl oxadiazoles could not be advanced beyond the open-chain precursors of the heterocyclics. Pyrolysis, thermolysis, and catalyzed cyclization reagents could not effect ring closure. A method was developed, however, to an oxadiazolone which can serve as a protective functionality for the iodinated aryl acid hydrazides.

• Research Organization: Lehigh Univ., Bethlehem, PA (USA)
• OSTI ID: 6977623
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
62 RADIOLOGY AND NUCLEAR MEDICINE
CARBOHYDRATES
IODINATION
GANGLIOSIDES
GLUCOPROTEINS
URINARY KETOSTEROIDS
ALDEHYDES
IODINE
KETONES
LABELLED COMPOUNDS
RADIOISOTOPES
RADIOPHARMACEUTICALS
CHEMICAL REACTIONS
DRUGS
ELEMENTS
GLYCOLIPIDS
GLYCOPROTEINS
HALOGENATION
HALOGENS
ISOTOPES
LIPIDS
NONMETALS
ORGANIC COMPOUNDS
PROTEINS
SACCHARIDES
400202* - Isotope Effects
Isotope Exchange
& Isotope Separation
550604 - Medicine- Unsealed Radionuclides in Therapy- (1980-)