Stereo and regioselectivity in ''Activated'' tritium reactions
To investigate the stereo and positional selectivity of the microwave discharge activation (MDA) method, the tritium labeling of several amino acids was undertaken. The labeling of L-valine and the diastereomeric pair L-isoleucine and L-alloisoleucine showed less than statistical labeling at the ..cap alpha..-amino C-H position mostly with retention of configuration. Labeling predominated at the single ..beta.. C-H tertiary (methyne) position. The labeling of L-valine and L-proline with and without positive charge on the ..cap alpha..-amino group resulted in large increases in specific activity (greater than 10-fold) when positive charge was removed by labeling them as their sodium carboxylate salts. Tritium NMR of L-proline labeled both as its zwitterion and sodium salt showed also large differences in the tritium distribution within the molecule. The distribution preferences in each of the charge states are suggestive of labeling by an electrophilic like tritium species(s). 16 refs., 5 tabs.
- Research Organization:
- Brookhaven National Lab., Upton, NY (USA); Pennsylvania Univ., Philadelphia (USA). Cerebrovascular Research Center; Columbia Univ., New York (USA). Coll. of Physicians and Surgeons
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 7095249
- Report Number(s):
- BNL-41770; CONF-880787-2; ON: DE89001099; TRN: 88-035761
- Resource Relation:
- Conference: 3. international symposium on the synthesis and applications of isotopically labeled compounds, Innsbruck, Austria, 17 Jul 1988; Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
LEUCINE
LABELLING
PROLINE
VALINE
AMINO ACIDS
CHEMICAL BONDS
ISOMERS
MOLECULAR STRUCTURE
STEREOCHEMISTRY
TRITIUM
AMINES
AZOLES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBOXYLIC ACIDS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HYDROGEN ISOTOPES
ISOTOPES
LIGHT NUCLEI
NUCLEI
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PYRROLES
PYRROLIDINES
RADIOISOTOPES
YEARS LIVING RADIOISOTOPES
550601* - Medicine- Unsealed Radionuclides in Diagnostics
550200 - Biochemistry