Synthesis and biologic evaluation of 1-(/sup 11/C)-3,3-dimethylheptadecanoic acid
1-(/sup 11/C)-3,3-dimethylheptadecanoic acid ((/sup 11/C)DMHDA) has been prepared for evaluation as a potential myocardial metabolism indicator based on an expected intrinsic stability toward beta-oxidative metabolic processes. Synthesis of this novel branched-chain fatty acid was accomplished by copper-catalyzed addition of tetradecylmagnesium bromide to diethylisopropylidenemalonate. Subsequent saponification and decarboxylation afforded 3,3-dimethylheptadecanoic acid (DMHDA) that was converted to the corresponding alkyl bromide by means of a modified Hunsdiecker reaction. Carboxylation of 2,2-dimethylhexadecylmagnesium bromide with /sup 11/CO/sub 2/ gave (/sup 11/C)DMHDA. Carbon-11 DMHDA showed moderate myocardial uptake in fasted rats, albeit lower than that reported for the 3-monomethyl analog. Considerable washout of radioactivity from the heart was also observed over the first 30 min postinjection. Imaging in dogs likewise showed disappointing heart uptake with much higher localization in the lung. These data suggest that gem-dimethyl substitution of the beta-position in long chain fatty acids is not only insufficient for enhanced myocardial uptake and retention, but also, may be deleterious when compared with beta-monomethylation.
- Research Organization:
- Massachusetts General Hospital, Boston
- OSTI ID:
- 5400893
- Journal Information:
- J. Nucl. Med.; (United States), Vol. 29:1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
RADIOPHARMACEUTICALS
CHEMICAL PREPARATION
TISSUE DISTRIBUTION
CARBON 11
DECANOIC ACID
DOGS
METABOLISM
MYOCARDIUM
RATS
TRACER TECHNIQUES
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BODY
CARBON ISOTOPES
CARBOXYLIC ACIDS
CARDIOVASCULAR SYSTEM
DISTRIBUTION
DRUGS
EVEN-ODD NUCLEI
HEART
ISOTOPE APPLICATIONS
ISOTOPES
LABELLED COMPOUNDS
LIGHT NUCLEI
MAMMALS
MINUTES LIVING RADIOISOTOPES
MONOCARBOXYLIC ACIDS
MUSCLES
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
RADIOISOTOPES
RODENTS
SYNTHESIS
VERTEBRATES
550601* - Medicine- Unsealed Radionuclides in Diagnostics