SYNTHESIS OF [C-14] N-[(TRIMETHYLAMINEBORYL)CARBONYL]-PHENYLALANINE-METHYL ESTER

Reported is the synthesis of [C-14]-L-N-[(trimethylamineboryl)carbonyl]-phenylalanine methyl ester, a boron containing alpha-amino acid dipeptide analog with anti-neoplastic, anti-inflammatory, and hypolipidemic activities. The C-14 label is universally distributed among all carbon positions of the phenylalanine portion of the molecule. Briefly, the dipeptide is prepared by reacting the phenylalanine methyl ester hydrochloride salt with trimethylamine-carboxyborane, triphenylphospine (TPP), CCl4, and triethylamine (TEA) in acetonitrile, for 24 hours. The final product afforded a specific activity of 5.71 mCi/mmol.