Sterochemical consequences of hydrogen exchange as a result of tritium atom reactions on solid aliphatic amino acids

Journal Article · Wed Jul 20 04:00:00 EDT 1977 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00457a019· OSTI ID:7295139

Ehrenkaufer, R L.E. ^[1]; Hembree, W C; Lieberman, S; Wolf, A P

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1. Brookhaven National Lab., Upton, NY

The products of stereochemistry resulting from radicals generated by the interaction of tritium atoms with L-isoleucine and L-alloisoleucine in the solid phase were determined. Among the four possible tritiated stereoisomers for each amino acid the major product was the parent L-amino acid (approximately 70 percent in each case) with the major fraction of the labeling being in positions other than the ..cap alpha.. position. Approximately 30 percent of the labeling resulted in the diastereomeric product by reaction at either the ..cap alpha.. or ..beta.. position, with the major pathway being ..beta..-inversion. The yield of products from ..cap alpha..-carbon attack of L-isoleucine was minor (7.9 percent) and occurred with net retention. Labeling at the ..cap alpha..-carbon of alloisoleucine was less than 1 percent. Tritiated glycine was formed from both amino acids by cleavage of the alkyl side chain. This may result from the excitation decomposition of the intermediates formed from recombination of ..cap alpha.. (or ..beta..) amino acid radicals with tritium. Determination of the stereochemical and chemical consequences of radical formation at chiral centers provides a sensitive probe for studying the consequences of tritium (hydrogen or deuterium) atom reactions.

• OSTI ID: 7295139
• Journal Information: J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 99:15; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400303* -- Organic Chemistry-- Isotope Exchange & Isotope Separation-- (-1987)
AMINO ACIDS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBOXYLIC ACIDS
CHEMICAL REACTION KINETICS
CHEMICAL REACTION YIELD
GLYCINE
HYDROGEN ISOTOPES
ISOTOPES
ISOTOPIC EXCHANGE
KINETICS
LIGHT NUCLEI
NUCLEI
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
RADIOISOTOPES
REACTION KINETICS
STEREOCHEMISTRY
TRITIUM
YEARS LIVING RADIOISOTOPES
YIELDS